Patent Grant
10947455
The present invention relates generally to the field of coke plants for producing coke from coal. Coke is an important raw material used to make steel. Coke is produced by driving off the volatile fraction of coal, which is typically about 25% of the mass. Hot exhaust gases generated by the coke making process are ideally recaptured and used to generate electricity. One style of coke oven which is suited to recover these hot exhaust gases are Horizontal Heat Recovery (HHR) ovens which have a unique environmental advantage over chemical byproduct ovens based upon the relative operating atmospheric pressure conditions inside the oven. HHR ovens operate under negative pressure whereas chemical byproduct ovens operate at a slightly positive atmospheric pressure. Both oven types are typically constructed of refractory bricks and other materials in which creating a substantially airtight environment can be a challenge because small cracks can form in these structures during day-to-day operation. Chemical byproduct ovens are kept at a positive pressure to avoid oxidizing recoverable products and overheating the ovens. Conversely, HHR ovens are kept at a negative pressure, drawing in air from outside the oven to oxidize the coal volatiles and to release the heat of combustion within the oven. These opposite operating pressure conditions and combustion systems are important design differences between HHR ovens and chemical byproduct ovens. It is important to minimize the loss of volatile gases to the environment so the combination of positive atmospheric conditions and small openings or cracks in chemical byproduct ovens allow raw coke oven gas (“COG”) and hazardous pollutants to leak into the atmosphere. Conversely, the negative atmospheric conditions and small openings or cracks in the HHR ovens or locations elsewhere in the coke plant simply allow additional air to be drawn into the oven or other locations in the coke plant so that the negative atmospheric conditions resist the loss of COG to the atmosphere.
One embodiment of the invention relates to a coke oven including an oven chamber, an uptake duct in fluid communication with the oven chamber, the uptake duct being configured to receive exhaust gases from the oven chamber, an uptake damper in fluid communication with the uptake duct, the uptake damper being positioned at any one of multiple positions including fully opened and fully closed, the uptake damper configured to control an oven draft, an actuator configured to alter the position of the uptake damper between the positions in response to a position instruction, a sensor configured to detect an operating condition of the coke oven, wherein the sensor includes one of a draft sensor configured to detect the oven draft, a temperature sensor configured to detect an uptake duct temperature or a sole flue temperature, and an oxygen sensor configured to detect an uptake duct oxygen concentration in the uptake duct, and a controller in communication with the actuator and with the sensor, the controller being configured to provide the position instruction to the actuator in response to the operating condition detected by the sensor.
Another embodiment of the invention relates to a method of operating a coke plant including the steps of operating multiple coke ovens to produce coke and exhaust gases, wherein each coke oven includes an uptake damper adapted to control an oven draft in the coke oven, directing the exhaust gases from each coke oven to a common tunnel, fluidly connecting multiple heat recovery steam generators to the common tunnel, operating all of the heat recovery steam generators and dividing the exhaust gases such that a portion of the exhaust gases flows to each of the heat recovery steam generators, and automatically controlling the uptake damper of each coke oven to maintain the oven draft of each coke oven at or above a targeted oven draft.
Another embodiment of the invention relates to a method of operating a coke plant including the steps of operating multiple coke ovens to produce coke and exhaust gases, wherein each coke oven includes an uptake damper adapted to control a flow of exhaust gases exiting the coke oven, directing the exhaust gases from each coke oven to a common tunnel, fluidly connecting multiple heat recovery steam generators to the common tunnel via multiple crossover ducts, wherein each heat recovery steam generator includes a heat recovery steam generator damper adapted to control a flow of exhaust gases through the heat recovery steam generator and wherein each crossover duct is connected to one of the heat recovery steam generators and connected to the common tunnel at an intersection, fluidly connecting a draft fan to the heat recovery steam generators, wherein the draft fan is located downstream of the heat recovery steam generators, operating all of the heat recovery steam generators and dividing the exhaust gases such that a portion of the exhaust gases flows to each of the heat recovery steam generators, exhausting the exhaust gases from the coke plant through a main stack, wherein the main stack is located downstream of the draft fan, detecting an operating condition downstream of the coke ovens with a sensor, and automatically controlling at least one of the uptake dampers, the heat recovery steam generator dampers, and the draft fan in response to the detected operating condition.
Another embodiment of the invention relates to a method of operating a coke oven including the steps of operating a coke oven to produce coke and exhaust gases, detecting an oven draft in the coke oven, adjusting a position of a first uptake damper fluidly connected to a first sole flue labyrinth and a position of a second uptake damper fluidly connected to a second sole flue labyrinth to maintain the detected oven draft at least at a targeted oven draft, detecting a first sole flue temperature in the first sole flue labyrinth, detecting a second sole flue temperature in the second sole flue labyrinth, comparing the first sole flue temperature to the second sole flue temperature, and biasing the position of the first uptake damper relative to the position of the second uptake damper in response to the comparison of the first sole flue temperature to the second sole flue temperature to maintain the first sole flue temperature and the second sole flue temperature within a specified temperature range.
Referring to
More structural detail of each oven 105 is shown in
In order to provide the ability to control gas flow through the uptake ducts 225 and within ovens 105, each uptake duct 225 also includes an uptake damper 230. The uptake damper 230 can be positioned at number of positions between fully open and fully closed to vary the amount of oven draft in the oven 105. As used herein, “draft” indicates a negative pressure relative to atmosphere. For example a draft of 0.1 inches of water indicates a pressure 0.1 inches of water below atmospheric pressure. Inches of water is a non-SI unit for pressure and is conventionally used to describe the draft at various locations in a coke plant. If a draft is increased or otherwise made larger, the pressure moves further below atmospheric pressure. If a draft is decreased, drops, or is otherwise made smaller or lower, the pressure moves towards atmospheric pressure. By controlling the oven draft with the uptake damper 230, the air flow into the oven from the air inlets 190, 215, 227 as well as air leaks into the oven 105 can be controlled. Typically, an oven 105 includes two uptake ducts 225 and two uptake dampers 230, but the use of two uptake ducts and two uptake dampers is not a necessity, a system can be designed to use just one or more than two uptake ducts and two uptake dampers.
In operation, coke is produced in the ovens 105 by first loading coal into the oven chamber 185, heating the coal in an oxygen depleted environment, driving off the volatile fraction of coal and then oxidizing the volatiles within the oven 105 to capture and utilize the heat given off. The coal volatiles are oxidized within the ovens over a 48-hour coking cycle, and release heat to regeneratively drive the carbonization of the coal to coke. The coking cycle begins when the front door 165 is opened and coal is charged onto the oven floor 160. The coal on the oven floor 160 is known as the coal bed. Heat from the oven (due to the previous coking cycle) starts the carbonization cycle. Preferably, no additional fuel other than that produced by the coking process is used. Roughly half of the total heat transfer to the coal bed is radiated down onto the top surface of the coal bed from the luminous flame and radiant oven crown 180. The remaining half of the heat is transferred to the coal bed by conduction from the oven floor 160 which is convectively heated from the volatilization of gases in the sole flue 205. In this way, a carbonization process “wave” of plastic flow of the coal particles and formation of high strength cohesive coke proceeds from both the top and bottom boundaries of the coal bed at the same rate, preferably meeting at the center of the coal bed after about 45-48 hours.
Accurately controlling the system pressure, oven pressure, flow of air into the ovens, flow of air into the system, and flow of gases within the system is important for a wide range of reasons including to ensure that the coal is fully coked, effectively extract all heat of combustion from the volatile gases, effectively controlling the level of oxygen within the oven chamber 185 and elsewhere in the coke plant 100, controlling the particulates and other potential pollutants, and converting the latent heat in the exhaust gases to steam which can be harnessed for generation of steam and/or electricity. Preferably, each oven 105 is operated at negative pressure so air is drawn into the oven during the reduction process due to the pressure differential between the oven 105 and atmosphere. Primary air for combustion is added to the oven chamber 185 to partially oxidize the coal volatiles, but the amount of this primary air is preferably controlled so that only a portion of the volatiles released from the coal are combusted in the oven chamber 185 thereby releasing only a fraction of their enthalpy of combustion within the oven chamber 185. The primary air is introduced into the oven chamber 185 above the coal bed through the primary air inlets 190 with the amount of primary air controlled by the primary air dampers 195. The primary air dampers 195 can be used to maintain the desired operating temperature inside the oven chamber 185. The partially combusted gases pass from the oven chamber 185 through the downcomer channels 200 into the sole flue 205 where secondary air is added to the partially combusted gases. The secondary air is introduced through the secondary air inlet 215 with the amount of secondary air controlled by the secondary air damper 220. As the secondary air is introduced, the partially combusted gases are more fully combusted in the sole flue 205 extracting the remaining enthalpy of combustion which is conveyed through the oven floor 160 to add heat to the oven chamber 185. The nearly fully combusted exhaust gases exit the sole flue 205 through the uptake channels 210 and then flow into the uptake duct 225. Tertiary air is added to the exhaust gases via the tertiary air inlet 227 with the amount of tertiary air controlled by the tertiary air damper 229 so that any remaining fraction of uncombusted gases in the exhaust gases are oxidized downstream of the tertiary air inlet 227.
At the end of the coking cycle, the coal has carbonized to produce coke. The coke is preferably removed from the oven 105 through the rear door 170 utilizing a mechanical extraction system. Finally, the coke is quenched (e.g., wet or dry quenched) and sized before delivery to a user.
As shown in
In the HRSG 120, the latent heat from the exhaust gases expelled from the ovens 105 is recaptured and preferably used to generate steam. The steam produced in the HRSGs 120 is routed via steam lines 150 to the cogeneration plant 155, where the steam is used to generate electricity. After the latent heat from the exhaust gases has been extracted and collected, the cooled exhaust gases exit the HRSG 0.120 and enter the cooled gas duct 125. All of the HRSGs 120 are fluidly connected to the cooled gas duct 125. With this structure, all of the components between the ovens 105 and the cooled gas duct 125 including the uptake ducts 225, the common tunnel 110, the crossover duct 115s, and the HRSGs 120 form the hot exhaust system. The combined cooled exhaust gases from all of the HRSGs 120 flow to the FGD system 130, where sulfur oxides (SOO are removed from the cooled exhaust gases the cooled, desulfurized exhaust gases flow from the FGD system 130 to the baghouse 135, where particulates are removed, resulting in cleaned exhaust gases. The cleaned exhaust gases exit the baghouse 135 through the draft fan 140 and are dispersed to the atmosphere via the main gas stack 145. The draft fan 140 creates the draft required to cause the described flow of exhaust gases and depending upon the size and operation of the system, one or more draft fans 140 can be used. Preferably, the draft fan 140 is an induced draft fan. The draft fan 140 can be controlled to vary the draft through the coke plant 100. Alternatively, no draft fan 140 is included and the necessary draft is produced due to the size of the main gas stack 145.
Under normal operating conditions, the entire system upstream of the draft fan 140 is maintained at a draft. Therefore, during operation, there is a slight bias of airflow from the ovens 105 through the entire system to the draft fan 140. For emergency situations, a bypass exhaust stack 240 is provided for each oven block 235. Each bypass exhaust stack 240 is located at an intersection 245 between the common tunnel 110 and a crossover duct 115. Under emergency situations, hot exhaust gases emanating from the oven block 235 associated with a crossover duct 115 can be vented to atmosphere via the related bypass exhaust stack 240. The release of hot exhaust gas through the bypass exhaust stack 240 is undesirable for many reasons including environmental concerns and energy consumption. Additionally, the output of the cogeneration plant 155 is reduced because the offline H.RSG 120 is not producing steam.
In a conventional HHR coke plant when a HRSG is offline due to scheduled maintenance, an unexpected emergency, or other reason, the exhaust gases from the associated oven block can be vented to atmosphere through the associated bypass exhaust stack because there is nowhere else for the exhaust gases to go due to gas flow limitations imposed by the common tunnel design and draft. If the exhaust gases were not vented to atmosphere through the bypass exhaust stack, they would cause undesired outcomes (e.g., positive pressure relative to atmosphere in an oven or ovens, damage to the offline HRSG) at other locations in the coke plant.
In the HHR coke plant 100 described herein, it is possible to avoid the undesirable loss of untreated exhaust gases to the environment by directing the hot exhaust gases that would normally flow to an offline HRSG to one or more of the online HRSGs 120. In other words, it is possible to share the exhaust or flue gases of each oven block 235 along the common tunnel 110 and among multiple HRSGs 120 rather than a conventional coke plant where the vast majority of exhaust gases from an oven block flow to the single HRSG associated with that oven block. While some amount of exhaust gases may flow along the common tunnel of a conventional coke plant (e.g., from a first oven block to the HRSG associated with the adjacent oven block), a conventional coke plant cannot be operated to transfer all of the exhaust gases from an oven block associated with an offline HRSG to one or more online HRSGs. In other words, it is not possible in a conventional coke plant for all of the exhaust gases that would typically flow to a first offline HRSG to be transferred or gas shared along the common tunnel to one or more different online HRSGs. “Gas sharing” is possible by implementing an increased effective flow area of the common tunnel 110, an increased draft in the common tunnel 110, the addition of at least one redundant HR.SG 120R, as compared to a conventional HHR coke plant, and by connecting all of the HRSGs 120 (standard and redundant) in parallel with each other. With gas sharing, it is possible to eliminate the undesirable expulsion of hot gases through the bypass exhaust stacks 240. In an example of a conventional HHR coke plant, an oven block of twenty coke ovens and a single HRSG are fluidly connected via a first common tunnel, two oven blocks totaling forty coke ovens and two HRSGs are connected by a second common tunnel, and two oven blocks totaling forty coke ovens and two HRSGs are connected by a third common tunnel, but gas sharing of all of the exhaust gases along the second common tunnel and along the third common tunnel from an oven block associated with an offline HRSG to the remaining online HRSG is not possible.
Maintaining drafts having certain minimum levels or targets with the hot exhaust gas sharing system is necessary for effective gas sharing without adversely impacting the performance of the ovens 105. The values recited for various draft targets are measured under normal steady-state operating conditions and do not include momentary, intermittent, or transient fluctuations in the draft at the specified location. Each oven 105 must maintain a draft (“oven draft”), that is, a negative pressure relative to atmosphere. Typically, the targeted oven draft is at least 0.1 inches of water. In some embodiments, the oven draft is measured in the oven chamber 185. During gas sharing along the common tunnel 110, the “intersection draft” at one or more of the intersections 245 between the common tunnel. 110 and the crossover ducts 115 and/or the “common tunnel draft” at one or more locations along the common tunnel 110 must be above a targeted draft (e.g., at least 0.7 inches of water) to ensure proper operation of the system. The common tunnel draft is measured upstream of the intersection draft (i.e., between an intersection 245 and the coke ovens 105) and is therefore typically lower than the intersection draft. In some embodiments the targeted intersection draft and/or the targeted common tunnel draft during gas sharing can be at least 1.0 inches of water and in other embodiments the targeted intersection draft and/or the targeted common tunnel draft during gas sharing can be at least 2.0 inches of water. Hot exhaust gas sharing eliminates the discharge of hot exhaust gases to atmosphere and increases the efficiency of the cogeneration plant 155. It is important to note that a hot exhaust gas sharing HHR coke plant 100 as described herein can be newly constructed or an existing, conventional HHR coke plant can be retrofitted according to the innovations described herein.
In an exhaust gas sharing system in which one or more HRSG 120 is offline, the hot exhaust gases ordinarily sent to the offline HRSGs 120 are not vented to atmosphere through the related bypass exhaust stack 240, but are instead routed through the common tunnel 110 to one or more different HRSGs 120. To accommodate the increased volume of gas flow through the common tunnel 110 during gas sharing, the effective flow area of the common tunnel 110 is greater than that of the common tunnel in a conventional HHR coke plant. This increased effective flow area can be achieved by increasing the inner diameter of the common tunnel 110 or by adding one or more additional common tunnels 110 to the hot exhaust system in parallel with the existing common tunnel 110 (as shown in
Hot exhaust gas sharing also requires that during gas sharing the common tunnel 110 be maintained at a higher draft than the common tunnel of a conventional HHR coke plant. In a conventional HHR coke plant, the intersection draft and the common tunnel draft are below 0.7 inches of water under normal steady-state operating conditions. A conventional HHR coke plant has never been operated such that the common tunnel operates at a high intersection draft or a high common tunnel draft (at or above 0.7 inches of water) because of concerns that the high intersection draft and the high common tunnel draft would result in excess air in the oven chambers. To allow for gas sharing along the common tunnel 110, the intersection draft at one or more intersections 245 must be maintained at least at 0.7 inches of water. In some embodiments, the intersection draft at one or more intersections 245 is maintained at least at 1.0 inches of water or at least at 2.0 inches of water. Alternatively or additionally, to allow for gas sharing along the common tunnel 110, the common tunnel draft at one or more locations along the common tunnel 110 must be maintained at least at 0.7 inches of water. In some embodiments, the common tunnel draft at one or more locations along the common tunnel 110 is maintained at least at 1.0 inches of water or at least at 2.0 inches of water. Maintaining such a high draft at one or more intersections 245 or at one or more locations along the common tunnel 110 ensures that the oven draft in all of the ovens 105 will be at least 0.1 inches of water when a single HSRG 120 is offline and provides sufficient draft for the exhaust gases from the oven block 235 associated with the offline HRSG 120 to flow to an online HSRG 120. While in the gas sharing operating mode (i.e., when at least one HRSG 120 is offline), the draft along the common tunnel 110 and at the different intersections 245 will vary. For example, if the HRSG 120 closest to one end of the common tunnel 110 is offline, the common tunnel draft at the proximal end of the common tunnel 110 will be around 0.1 inches of water and the common tunnel draft at the opposite, distal end of the common tunnel 11.0 will be around 1.0 inches of water. Similarly, the intersection draft at the intersection 245 furthest from the offline HRSG 120 will be relatively high (i.e., at least 0.7 inches of water) and the intersection draft at the intersection 245 associated with the offline HRSG 120 will be relatively low (i.e., lower than the intersection draft at the previously-mentioned intersection 245 and typically below 0.7 inches of water).
Alternatively, the HHR coke plant 100 can be operated in two operating modes: a normal operating mode for when all of the HRSGs 120 are online and a gas sharing operating mode for when at least one of the HRSGs 120 is offline. In the normal operating mode, the common tunnel 110 is maintained at a common tunnel draft and intersection drafts similar to those of a conventional HHR coke plant (typically, the intersection draft is between 0.5 and 0.6 inches of water and the common tunnel draft at a location near the intersection is between 0.4 and 0.5 inches of water). The common tunnel draft and the intersection draft can vary during the normal operating mode and during the gas sharing mode. In most situations, when a HRSG 120 goes offline, the gas sharing mode begins and the intersection draft at one or more intersections 245 and/or the common tunnel draft at one or more locations along the common tunnel 110 is raised. In some situations, for example, when the HRSG 120 furthest from the redundant HRSG 120R is offline, the gas sharing mode will begin and will require an intersection draft and/or a common tunnel draft of at least 0.7 inches of water (in some embodiments, between 1.2 and 1.3 inches of water) to allow for gas sharing along the common tunnel 110. In other situations, for example, when a HRSG 120 positioned next to the redundant HRSG 120R which is offline, the gas sharing mode may not be necessary, that is gas sharing may be possible in the normal operating mode with the same operating conditions prior to the HRSG 120 going offline, or the gas sharing mode will begin and will require only a slight increase in the intersection draft and/or a common tunnel draft. In general, the need to go to a higher draft in the gas sharing mode will depend on where the redundant HRSG 120R is located relative to the offline HRSG 120. The further away the redundant HRSG 1120R fluidly is form the tripped HRSG 120, the higher the likelihood that a higher draft will be needed in the gas sharing mode.
Increasing the effective flow area and the intersection draft and/or the common tunnel draft to the levels described above also allows for more ovens 105 to be added to an oven block 235. In some embodiments, up to one hundred ovens form an oven block (i.e., are associated with a crossover duct).
The HR.SGs 120 found in a conventional HHR coke plant at a ratio of twenty ovens to one HRSG are referred to as the “standard HRSGs.” The addition of one or more redundant HRSGs 120R results in an overall oven to HRSG ratio of less than 20:1. Under normal operating conditions, the standard HRSGs 120 and the redundant HRSG 120R are all in operation. It is impractical to bring the redundant HRSG 120R online and offline as needed because the start-up time for a HRSG would result in the redundant HRSG 120R only being available on a scheduled basis and not for emergency purposes. An alternative to installing one or more redundant HRSGs would be to increase the capacity of the standard FIRSGs to accommodate the increased exhaust gas flow during gas sharing. Under normal operating conditions with all of the high capacity HRSGs online, the exhaust gases from each oven block are conveyed to the associated high capacity HRSGs. In the event that one of the high capacity HRSGs goes offline, the other high capacity HRSGs would be able to accommodate the increased flow of exhaust gases.
In a gas sharing system as described herein, when one of the HRSGs 120 is offline the exhaust gases emanating from the various ovens 105 are shared and distributed among the remaining online HRSGs 120 such that a portion of the total exhaust gases are routed through the common tunnel 110 to each of the online HRSGs 120 and no exhaust gas is vented to atmosphere. The exhaust gases are routed amongst the various HRSGs 120 by adjusting a HRSG valve 250 associated with each HRSG 120 (shown in
In general, a larger common tunnel 110 can correlate to larger allowable mass flow rates relative to a conventional common tunnel for the same given desired pressure difference along the length of the common tunnel 110. The converse is also true, the larger common tunnel 110 can correlate to smaller pressure differences relative to a conventional common tunnel for the same given desired mass flow rate along the length of the common tunnel 110. Larger means larger effective flow area and not necessarily larger geometric cross sectional area. Higher common tunnel drafts can accommodate larger mass flow rates through the common tunnel 110. In general, higher temperatures can correlate to lower allowable mass flow rates for the same given desired pressure difference along the length of the tunnel. Higher exhaust gas temperatures should result in volumetric expansion of the gases. Since the total pressure losses can be approximately proportional to density and proportional to the square of the velocity, the total pressure losses can be higher for volumetric expansion because of higher temperatures. For example, an increase in temperature can result in a proportional decrease in density. However, an increase in temperature can result in an accompanying proportional increase in velocity which affects the total pressure losses more severely than the decrease in density. Since the effect of velocity on total pressure can be more of a squared effect while the density effect can be more of a linear one, there should be losses in total pressure associated with an increase in temperature for the flow in the common tunnel 110. Multiple, parallel, fluidly connected common tunnels (dual, multiple, or hybrid dual/multiple configurations) may be preferred for retrofitting existing conventional HHR coke plants into the gas sharing HHR coke plants described herein.
Although the sample gas-sharing HHR coke plant 100 illustrated in
As shown in
As shown in
As shown in
An oven draft sensor or oven pressure sensor 310 detects a pressure that is indicative of the oven draft and the oven draft sensor 310 can be located in the oven crown 180 or elsewhere in the oven chamber 185. Alternatively, the oven draft sensor 310 can be located at either of the automatic uptake dampers 305, in the sole flue 205, at either oven door 165 or 170, or in the common tunnel 110 near above the coke oven 105. In one embodiment, the oven draft sensor 310 is located in the top of the oven crown 180. The oven draft sensor 310 can be located flush with the refractory brick lining of the oven crown 180 or could extend into the oven chamber 185 from the oven crown 180. A bypass exhaust stack draft sensor 315 detects a pressure that is indicative of the draft at the bypass exhaust stack 240 (e.g., at the base of the bypass exhaust stack 240). In some embodiments, the bypass exhaust stack draft sensor 315 is located at the intersection 245. Additional draft sensors can be positioned at other locations in the coke plant 100. For example, a draft sensor in the common tunnel could be used to detect a common tunnel draft indicative of the oven draft in multiple ovens proximate the draft sensor. An intersection draft sensor 317 detects a pressure that is indicative of the draft at one of the intersections 245.
An oven temperature sensor 320 detects the oven temperature and can be located in the oven crown 180 or elsewhere in the oven chamber 185. A sole flue temperature sensor 325 detects the sole flue temperature and is located in the sole flue 205. In some embodiments, the sole flue 205 is divided into two labyrinths 205A and 205B with each labyrinth in fluid communication with one of the oven's two uptake ducts 225. A flue temperature sensor 325 is located in each of the sole flue labyrinths so that the sole flue temperature can be detected in each labyrinth. An uptake duct temperature sensor 330 detects the uptake duct temperature and is located in the uptake duct 225. A common tunnel temperature sensor 335 detects the common tunnel temperature and is located in the common tunnel 110. A HRSG inlet temperature sensor 340 detects the HR.SG inlet temperature and is located at or near the inlet of the HRSG 120. Additional temperature sensors can be positioned at other locations in the coke plant 100.
An uptake duct oxygen sensor 345 is positioned to detect the oxygen concentration of the exhaust gases in the uptake duct 225. An HRSG inlet oxygen sensor 350 is positioned to detect the oxygen concentration of the exhaust gases at the inlet of the HRSG 120. A main stack oxygen sensor 360 is positioned to detect the oxygen concentration of the exhaust gases in the main stack 145 and additional oxygen sensors can be positioned at other locations in the coke plant 100 to provide information on the relative oxygen concentration at various locations in the system.
A flow sensor detects the gas flow rate of the exhaust gases. For example, a flow sensor can be located downstream of each of the HRSGs 120 to detect the flow rate of the exhaust gases exiting each HRSG 120. This information can be used to balance the flow of exhaust gases through each HRSG 120 by adjusting the HRSG dampers 250 and thereby optimize gas sharing among the HRSGs 120. Additional flow sensors can be positioned at other locations in the coke plant 100 to provide information on the gas flow rate at various locations in the system.
Additionally, one or more draft or pressure sensors, temperature sensors, oxygen sensors, flow sensors, and/or other sensors may be used at the air quality control system 130 or other locations downstream of the HRSGs 120.
It can be important to keep the sensors clean. One method of keeping a sensor clean is to periodically remove the sensor and manually clean it. Alternatively, the sensor can be periodically subjected to a burst, blast, or flow of a high pressure gas to remove build up at the sensor. As a further alternatively, a small continuous gas flow can be provided to continually clean the sensor.
The automatic uptake damper 305 includes the uptake damper 230 and an actuator 365 configured to open and close the uptake damper 230. For example, the actuator 365 can be a linear actuator or a rotational actuator. The actuator 365 allows the uptake damper 230 to be infinitely controlled between the fully open and the fully closed positions. The actuator 365 moves the uptake damper 230 amongst these positions in response to the operating condition or operating conditions detected by the sensor or sensors included in the automatic draft control system 300. This provides much greater control than a conventional uptake damper. A conventional uptake damper has a limited number of fixed positions between fully open and fully closed and must be manually adjusted amongst these positions by an operator.
The uptake dampers 230 are periodically adjusted to maintain the appropriate oven draft (e.g., at least 0.1 inches of water) which changes in response to many different factors within the ovens or the hot exhaust system. When the common tunnel 110 has a relatively low common tunnel draft (i.e., closer to atmospheric pressure than a relatively high draft), the uptake damper 230 can be opened to increase the oven draft to ensure the oven draft remains at or above 0.1 inches of water. When the common tunnel 110 has a relatively high common tunnel draft, the uptake damper 230 can be closed to decrease the oven draft, thereby reducing the amount of air drawn into the oven chamber 185.
With conventional uptake dampers, the uptake dampers are manually adjusted and therefore optimizing the oven draft is part art and part science, a product of operator experience and awareness. The automatic draft control system 300 described herein automates control of the uptake dampers 230 and allows for continuous optimization of the position of the uptake dampers 230 thereby replacing at least some of the necessary operator experience and awareness. The automatic draft control system 300 can be used to maintain an oven draft at a targeted oven draft (e.g., at least 0.1 inches of water), control the amount of excess air in the oven 105, or achieve other desirable effects by automatically adjusting the position of the uptake damper 230. The automatic draft control system 300 makes it easier to achieve the gas sharing described above by allowing for a high intersection draft at one or more of the intersections 245 and/or a high common tunnel draft at one or more locations along the common tunnel 110 while maintaining oven drafts low enough to prevent excess air leaks into the ovens 105. Without automatic control, it would be difficult if not impossible to manually adjust the uptake dampers 230 as frequently as would be required to maintain the oven draft of at least 0.1 inches of water without allowing the pressure in the oven to drift to positive. Typically, with manual control, the target oven draft is greater than 0.1 inches of water, which leads to more air leakage into the coke oven 105. For a conventional uptake damper, an operator monitors various oven temperatures and visually observes the coking process in the coke oven to determine when to and how much to adjust the uptake damper. The operator has no specific information about the draft (pressure) within the coke oven.
The actuator 365 positions the uptake damper 230 based on position instructions received from a controller 370. The position instructions can be generated in response to the draft, temperature, oxygen concentration, or gas flow rate detected by one or more of the sensors discussed above, control algorithms that include one or more sensor inputs, or other control algorithms. The controller 370 can be a discrete controller associated with a single automatic uptake damper 305 or multiple automatic uptake dampers 305, a centralized controller (e.g., a distributed control system or a programmable logic control system), or a combination of the two. In some embodiments, the controller 370 utilizes proportional-integral-derivative (“PID”) control.
The automatic draft control system 300 can, for example, control the automatic uptake damper 305 of an oven 105 in response to the oven draft detected by the oven draft sensor 310. The oven draft sensor 310 detects the oven draft and outputs a signal indicative of the oven draft to the controller 370. The controller 370 generates a position instruction in response to this sensor input and the actuator 365 moves the uptake damper 230 to the position required by the position instruction. In this way, the automatic control system 300 can be used to maintain a targeted oven draft (e.g., at least 0.1 inches of water). Similarly, the automatic draft control system 300 can control the automatic uptake dampers 305, the HRSG dampers 250, and the draft fan 140, as needed, to maintain targeted drafts at other locations within the coke plant 100 (e.g., a targeted intersection draft or a targeted common tunnel draft). For example, for gas sharing as described above, the intersection draft at one or more intersections 245 and/or the common tunnel draft at one or more locations along the common tunnel 110 needs to be maintained at least at 0.7 inches of water. The automatic draft control system 300 can be placed into a manual mode to allow for manual adjustment of the automatic uptake dampers 305, the HRSG dampers, and/or the draft fan 140, as needed. Preferably, the automatic draft control system 300 includes a manual mode timer and upon expiration of the manual mode timer, the automatic draft control system 300 returns to automatic mode.
In some embodiments, the signal generated by the oven draft sensor 310 that is indicative of the detected pressure or draft is time averaged to achieve a stable pressure control in the coke oven 105. The time averaging of the signal can be accomplished by the controller 370. Time averaging the pressure signal helps to filter out normal fluctuations in the pressure signal and to filter out noise. Typically, the signal could be averaged over 30 seconds, 1 minute, 5 minutes, or over at least 10 minutes. In one embodiment, a rolling time average of the pressure signal is generated by taking 200 scans of the detected pressure at 50 milliseconds per scan. The larger the difference in the time-averaged pressure signal and the target oven draft, the automatic draft control system 300 enacts a larger change in the damper position to achieve the desired target draft. In some embodiments, the position instructions provided by the controller 370 to the automatic uptake damper 305 are linearly proportional to the difference in the time-averaged pressure signal and the target oven draft. In other embodiments, the position instructions provided by the controller 370 to the automatic uptake damper 305 are non-linearly proportional to the difference in the time-averaged pressure signal and the target oven draft. The other sensors previously discussed can similarly have time-averaged signals.
The automatic draft control system 300 can be operated to maintain a constant time-averaged oven draft within a specific tolerance of the target oven draft throughout the coking cycle. This tolerance can be, for example, +/−0.05 inches of water, +/−0.02 inches of water, or +/−0.01 inches of water.
The automatic draft control system 300 can also be operated to create a variable draft at the coke oven by adjusting the target oven draft over the course of the coking cycle. The target oven draft can be stepwise reduced as a function of the elapsed time of the coking cycle. In this manner, using a 48-hour coking cycle as an example, the target draft starts out relatively high (e.g., 0.2 inches of water) and is reduced every 12 hours by 0.05 inches of water so that the target oven draft is 0.2 inches of water for hours 1-12 of the coking cycle, 0.15 inches of water for hours 12-24 of the coking cycle, 0.01 inches of water for hours 24-36 of the coking cycle, and 0.05 inches of water for hours 36-48 of the coking cycle. Alternatively, the target draft can be linearly decreased throughout the coking cycle to a new, smaller value proportional to the elapsed time of the coking cycle.
As an example, if the oven draft of an oven 105 drops below the targeted oven draft (e.g., 0.1 inches of water) and the uptake damper 230 is fully open, the automatic draft control system 300 would increase the draft by opening at least one HRSG damper 250 to increase the oven draft. Because this increase in draft downstream of the oven 105 affects more than one oven 105, some ovens 105 might need to have their uptake dampers 230 adjusted (e.g., moved towards the fully closed position) to maintain the targeted oven draft (i.e., regulate the oven draft to prevent it from becoming too high). If the IMSG damper 250 was already fully open, the automatic damper control system 300 would need to have the draft fan 140 provide a larger draft. This increased draft downstream of all the HRSGs 120 would affect all the HRSG 120 and might require adjustment of the HRSG dampers 250 and the uptake dampers 230 to maintain target drafts throughout the coke plant 100.
As another example, the common tunnel draft can be minimized by requiring that at least one uptake damper 230 is fully open and that all the ovens 105 are at least at the targeted oven draft (e.g., 0.1 inches of water) with the HRSG dampers 250 and/or the draft fan 140 adjusted as needed to maintain these operating requirements.
As another example, the coke plant 100 can be run at variable draft for the intersection draft and/or the common tunnel draft to stabilize the air leakage rate, the mass flow, and the temperature and composition of the exhaust gases (e.g., oxygen levels), among other desirable benefits. This is accomplished by varying the intersection draft and/or the common tunnel draft from a relatively high draft (e.g., 0.8 inches of water) when the coke ovens 105 are pushed and reducing gradually to a relatively low draft (e.g., 0.4 inches of water), that is, running at relatively high draft in the early part of the coking cycle and at relatively low draft in the late part of the coking cycle. The draft can be varied continuously or in a step-wise fashion.
As another example, if the common tunnel draft decreases too much, the HRSG damper 250 would open to raise the common tunnel draft to meet the target common tunnel draft at one or more locations along the common tunnel 110 (e.g., 0.7 inches water) to allow gas sharing. After increasing the common tunnel draft by adjusting the HRSG damper 250, the uptake dampers 230 in the affected ovens 105 might be adjusted (e.g., moved towards the fully closed position) to maintain the targeted oven draft in the affected ovens 105 (i.e., regulate the oven draft to prevent it from becoming too high).
As another example, the automatic draft control system 300 can control the automatic uptake damper 305 of an oven 105 in response to the oven temperature detected by the oven temperature sensor 320 and/or the sole flue temperature detected by the sole flue temperature sensor or sensors 325. Adjusting the automatic uptake damper 305 in response to the oven temperature and or the sole flue temperature can optimize coke production or other desirable outcomes based on specified oven temperatures. When the sole flue 205 includes two labyrinths 205A and 205B, the temperature balance between the two labyrinths 205A and 205B can be controlled by the automatic draft control system 300. The automatic uptake damper 305 for each of the oven's two uptake ducts 225 is controlled in response to the sole flue temperature detected by the sole flue temperature sensor 325 located in labyrinth 205A or 205B associated with that uptake duct 225. The controller 370 compares the sole flue temperature detected in each of the labyrinths 205A and 205B and generates positional instructions for each of the two automatic uptake dampers 305 so that the sole flue temperature in each of the labyrinths 205A and 205B remains within a specified temperature range.
In some embodiments, the two automatic uptake dampers 305 are moved together to the same positions or synchronized. The automatic uptake damper 305 closest to the front door 165 is known as the “push-side” damper and the automatic uptake damper closet to the rear door 170 is known as the “coke-side” damper. In this manner, a single oven draft pressure sensor 310 provides signals and is used to adjust both the push- and coke-side automatic uptake dampers 305 identically. For example, if the position instruction from the controller to the automatic uptake dampers 305 is at 60% open, both push- and coke-side automatic uptake dampers 305 are positioned at 60% open. If the position instruction from the controller to the automatic uptake dampers 305 is 8 inches open, both push- and coke-side automatic uptake dampers 305 are 8 inches open. Alternatively, the two automatic uptake dampers 305 are moved to different positions to create a bias. For example, for a bias of 1 inch, if the position instruction for synchronized automatic uptake dampers 305 would be 8 inches open, for biased automatic uptake dampers 305, one of the automatic uptake dampers 305 would be 9 inches open and the other automatic uptake damper 305 would be 7 inches open. The total open area and pressure drop across the biased automatic uptake dampers 305 remains constant when compared to the synchronized automatic uptake dampers 305. The automatic uptake dampers 305 can be operated in synchronized or biased manners as needed. The bias can be used to try to maintain equal temperatures in the push-side and the coke-side of the coke oven 105. For example, the sole flue temperatures measured in each of the sole flue labyrinths 205A and 205B (one on the coke-side and the other on the push-side) can be measured and then corresponding automatic uptake damper 305 can be adjusted to achieve the target oven draft, while simultaneously using the difference in the coke- and push-side sole flue temperatures to introduce a bias proportional to the difference in sole flue temperatures between the coke-side sole flue and push-side sole flue temperatures. In this way, the push- and coke-side sole flue temperatures can be made to be equal within a certain tolerance. The tolerance (difference between coke- and push-side sole flue temperatures) can be 250° Fahrenheit, 1000 Fahrenheit, 50° Fahrenheit, or, preferably 250 Fahrenheit or smaller. Using state-of-the-art control methodologies and techniques, the coke-side sole flue and the push-side sole flue temperatures can be brought within the tolerance value of each other over the course of one or more hours (e.g., 1-3 hours), while simultaneously controlling the oven draft to the target oven draft within a specified tolerance (e.g., +1-0.01 inches of water). Biasing the automatic uptake dampers 305 based on the sole flue temperatures measured in each of the sole flue labyrinths 205A and 205B, allows heat to be transferred between the push side and coke side of the coke oven 105. Typically, because the push side and the coke side of the coke bed coke at different rates, there is a need to move heat from the push side to the coke side. Also, biasing the automatic uptake dampers 305 based on the sole flue temperatures measured in each of the sole flue labyrinths 205A and 205B, helps to maintain the oven floor at a relatively even temperature across the entire floor.
The oven temperature sensor 320, the sole flue temperature sensor 325, the uptake duct temperature sensor 330, the common tunnel temperature sensor 335, and the HRSG inlet temperature sensor 340 can be used to detect overheat conditions at each of their respective locations. These detected temperatures can generate position instructions to allow excess air into one or more ovens 105 by opening one or more automatic uptake dampers 305. Excess air (i.e., where the oxygen present is above the stoichiometric ratio for combustion) results in uncombusted oxygen and uncombusted nitrogen in the oven 105 and in the exhaust gases. This excess air has a lower temperature than the other exhaust gases and provides a cooling effect that eliminates overheat conditions elsewhere in the coke plant 100.
As another example, the automatic draft control system 300 can control the automatic uptake damper 305 of an oven 105 in response to uptake duct oxygen concentration detected by the uptake duct oxygen sensor 345. Adjusting the automatic uptake damper 305 in response to the uptake duct oxygen concentration can be done to ensure that the exhaust gases exiting the oven 105 are fully combusted and/or that the exhaust gases exiting the oven 105 do not contain too much excess air or oxygen. Similarly, the automatic uptake damper 305 can be adjusted in response to the HRSG inlet oxygen concentration detected by the HRSG inlet oxygen sensor 350 to keep the HRSG inlet oxygen concentration above a threshold concentration that protects the HRSG 120 from unwanted combustion of the exhaust gases occurring at the HRSG 120. The HRSG inlet oxygen sensor 350 detects a minimum oxygen concentration to ensure that all of the combustibles have combusted before entering the HRSG 120. Also, the automatic uptake damper 305 can be adjusted in response to the main stack oxygen concentration detected by the main stack oxygen sensor 360 to reduce the effect of air leaks into the coke plant 100. Such air leaks can be detected based on the oxygen concentration in the main stack 145.
The automatic draft control system 300 can also control the automatic uptake dampers 305 based on elapsed time within the coking cycle. This allows for automatic control without having to install an oven draft sensor 310 or other sensor in each oven 105. For example, the position instructions for the automatic uptake dampers 305 could be based on historical actuator position data or damper position data from previous coking cycles for one or more coke ovens 105 such that the automatic uptake damper 305 is controlled based on the historical positioning data in relation to the elapsed time in the current coking cycle.
The automatic draft control system 300 can also control the automatic uptake dampers 305 in response to sensor inputs from one or more of the sensors discussed above. Inferential control allows each coke oven 105 to be controlled based on anticipated changes in the oven's or coke plant's operating conditions (e.g., draft/pressure, temperature, oxygen concentration at various locations in the oven 105 or the coke plant 100) rather than reacting to the actual detected operating condition or conditions. For example, using inferential control, a change in the detected oven draft that shows that the oven draft is dropping towards the targeted oven draft (e.g., at least 0.1 inches of water) based on multiple readings from the oven draft sensor 310 over a period of time, can be used to anticipate a predicted oven draft below the targeted oven draft to anticipate the actual oven draft dropping below the targeted oven draft and generate a position instruction based on the predicted oven draft to change the position of the automatic uptake damper 305 in response to the anticipated oven draft, rather than waiting for the actual oven draft to drop below the targeted oven draft before generating the position instruction. Inferential control can be used to take into account the interplay between the various operating conditions at various locations in the coke plant 100. For example, inferential control taking into account a requirement to always keep the oven under negative pressure, controlling to the required optimal oven temperature, sole flue temperature, and maximum common tunnel temperature while minimizing the oven draft is used to position the automatic uptake damper 305. Inferential control allows the controller 370 to make predictions based on known coking cycle characteristics and the operating condition inputs provided by the various sensors described above. Another example of inferential control allows the automatic uptake dampers 305 of each oven 105 to be adjusted to maximize a control algorithm that results in an optimal balance among coke yield, coke quality, and power generation. Alternatively, the uptake dampers 305 could be adjusted to maximize one of coke yield, coke quality, and power generation.
Alternatively, similar automatic draft control systems could be used to automate the primary air dampers 195, the secondary air dampers 220, and/or the tertiary air dampers 229 in order to control the rate and location of combustion at various locations within an oven 105. For example, air could be added via an automatic secondary air damper in response to one or more of draft, temperature, and oxygen concentration detected by an appropriate sensor positioned in the sole flue 205 or appropriate sensors positioned in each of the sole flue labyrinths 205A and 205B.
As utilized herein, the terms “approximately,” “about,” “substantially,” and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and are considered to be within the scope of the disclosure.
It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples).
It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure.
It is also important to note that the constructions and arrangements of the apparatus, systems, and methods as described and shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present disclosure.
The present disclosure contemplates methods, systems and program products on any machine-readable media for accomplishing various operations. The embodiments of the present disclosure may be implemented using existing computer processors, or by a special purpose computer processor for an appropriate system, incorporated for this or another purpose, or by a hardwired system. Embodiments within the scope of the present disclosure include program products comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. Such machine-readable media can be any available media that can be accessed by a general purpose or special purpose computer or other machine with a processor. By way of example, such machine-readable media can comprise RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a general purpose or special purpose computer or other machine with a processor. When information is transferred or provided over a network or another communications connection (either hardwired, wireless, or a combination of hardwired or wireless) to a machine, the machine properly views the connection as a machine-readable medium. Thus, any such connection is properly termed a machine-readable medium. Combinations of the above are also included within the scope of machine-readable media. Machine-executable instructions include, for example, instructions and data which cause a general purpose computer, special purpose computer, or special purpose processing machines to perform a certain function or group of functions.
The present application is a divisional of U.S. patent application Ser. No. 13/589,009, filed Aug. 17, 2012, the disclosure of which is incorporated herein by reference in its entirety.
| Number | Name | Date | Kind |
|---|---|---|---|
| 425797 | Hunt | Apr 1890 | A |
| 469868 | Osbourn | Mar 1892 | A |
| 845719 | Schniewind | Feb 1907 | A |
| 976580 | Krause | Jul 1909 | A |
| 1140798 | Carpenter | May 1915 | A |
| 1424777 | Schondeling | Aug 1922 | A |
| 1430027 | Plantinga | Sep 1922 | A |
| 1486401 | Van Ackeren | Mar 1924 | A |
| 1530995 | Geiger | Mar 1925 | A |
| 1572391 | Kiaiber | Feb 1926 | A |
| 1677973 | Marquard | Jul 1928 | A |
| 1705039 | Thornhill | Mar 1929 | A |
| 1721813 | Geipert | Jul 1929 | A |
| 1757682 | Palm | May 1930 | A |
| 1818370 | Wine | Aug 1931 | A |
| 1818994 | Kreisinger | Aug 1931 | A |
| 1830951 | Lovett | Nov 1931 | A |
| 1848818 | Becker | Mar 1932 | A |
| 1947499 | Schrader et al. | Feb 1934 | A |
| 1955962 | Jones | Apr 1934 | A |
| 2075337 | Burnaugh | Mar 1937 | A |
| 2141035 | Daniels | Dec 1938 | A |
| 2195466 | Otto | Apr 1940 | A |
| 2394173 | Harris et al. | Feb 1946 | A |
| 2424012 | Bangham et al. | Jul 1947 | A |
| 2649978 | Such | Aug 1953 | A |
| 2667185 | Beavers | Jan 1954 | A |
| 2723725 | Keiffer | Nov 1955 | A |
| 2756842 | Chamberlin et al. | Jul 1956 | A |
| 2813708 | Frey | Nov 1957 | A |
| 2827424 | Homan | Mar 1958 | A |
| 2873816 | Emil et al. | Feb 1959 | A |
| 2902991 | Whitman | Sep 1959 | A |
| 2907698 | Schulz | Oct 1959 | A |
| 3015893 | McCreary | Jan 1962 | A |
| 3033764 | Hannes | May 1962 | A |
| 3224805 | Clyatt | Dec 1965 | A |
| 3462345 | Kernan | Aug 1969 | A |
| 3511030 | Brown et al. | May 1970 | A |
| 3542650 | Kulakov | Nov 1970 | A |
| 3545470 | Paton | Dec 1970 | A |
| 3592742 | Thompson | Jul 1971 | A |
| 3616408 | Hickam | Oct 1971 | A |
| 3623511 | Levin | Nov 1971 | A |
| 3630852 | Nashan et al. | Dec 1971 | A |
| 3652403 | Knappstein et al. | Mar 1972 | A |
| 3676305 | Cremer | Jul 1972 | A |
| 3709794 | Kinzler et al. | Jan 1973 | A |
| 3710551 | Sved | Jan 1973 | A |
| 3746626 | Morrison, Jr. | Jul 1973 | A |
| 3748235 | Pries | Jul 1973 | A |
| 3784034 | Thompson | Jan 1974 | A |
| 3806032 | Pries | Apr 1974 | A |
| 3811572 | Tatterson | May 1974 | A |
| 3836161 | Pries | Oct 1974 | A |
| 3839156 | Jakobi et al. | Oct 1974 | A |
| 3844900 | Schulte | Oct 1974 | A |
| 3857758 | Mole | Dec 1974 | A |
| 3875016 | Schmidt-Balve | Apr 1975 | A |
| 3876143 | Rossow et al. | Apr 1975 | A |
| 3876506 | Dix et al. | Apr 1975 | A |
| 3878053 | Hyde | Apr 1975 | A |
| 3894302 | Lasater | Jul 1975 | A |
| 3897312 | Armour et al. | Jul 1975 | A |
| 3906992 | Leach | Sep 1975 | A |
| 3912091 | Thompson | Oct 1975 | A |
| 3917458 | Polak | Nov 1975 | A |
| 3928144 | Jakimowicz | Dec 1975 | A |
| 3930961 | Sustarsic et al. | Jan 1976 | A |
| 3933443 | Lohrmann | Jan 1976 | A |
| 3957591 | Riecker | May 1976 | A |
| 3959084 | Price | May 1976 | A |
| 3963582 | Helm et al. | Jun 1976 | A |
| 3969191 | Bollenbach | Jul 1976 | A |
| 3975148 | Fukuda et al. | Aug 1976 | A |
| 3984289 | Sustarsic et al. | Oct 1976 | A |
| 4004702 | Szendroi | Jan 1977 | A |
| 4004983 | Pries | Jan 1977 | A |
| 4025395 | Ekholm et al. | May 1977 | A |
| 4040910 | Knappstein et al. | Aug 1977 | A |
| 4045299 | MacDonald | Aug 1977 | A |
| 4059885 | Oldengott | Nov 1977 | A |
| 4067462 | Thompson | Jan 1978 | A |
| 4083753 | Rogers et al. | Apr 1978 | A |
| 4086231 | Ikio | Apr 1978 | A |
| 4093245 | Connor | Jun 1978 | A |
| 4100033 | Holter | Jul 1978 | A |
| 4111757 | Carimboli | Sep 1978 | A |
| 4124450 | MacDonald | Nov 1978 | A |
| 4135948 | Mertens et al. | Jan 1979 | A |
| 4141796 | Clark et al. | Feb 1979 | A |
| 4145195 | Knappstein et al. | Mar 1979 | A |
| 4147230 | Ormond et al. | Apr 1979 | A |
| 4162546 | Shortell et al. | Jul 1979 | A |
| 4181459 | Price | Jan 1980 | A |
| 4189272 | Gregor et al. | Feb 1980 | A |
| 4194951 | Pries | Mar 1980 | A |
| 4196053 | Grohmann | Apr 1980 | A |
| 4211608 | Kwasnoski et al. | Jul 1980 | A |
| 4211611 | Bocsanczy | Jul 1980 | A |
| 4213489 | Cain | Jul 1980 | A |
| 4213828 | Calderon | Jul 1980 | A |
| 4222748 | Argo et al. | Sep 1980 | A |
| 4222824 | Flockenhaus et al. | Sep 1980 | A |
| 4224109 | Flockenhaus et al. | Sep 1980 | A |
| 4225393 | Gregor et al. | Sep 1980 | A |
| 4235830 | Bennett et al. | Nov 1980 | A |
| 4239602 | La Bate | Dec 1980 | A |
| 4248671 | Belding | Feb 1981 | A |
| 4249997 | Schmitz | Feb 1981 | A |
| 4263099 | Porter | Apr 1981 | A |
| 4268360 | Tsuzuki et al. | May 1981 | A |
| 4271814 | Lister | Jun 1981 | A |
| 4284478 | Brommel | Aug 1981 | A |
| 4285772 | Kress | Aug 1981 | A |
| 4287024 | Thompson | Sep 1981 | A |
| 4289584 | Chuss et al. | Sep 1981 | A |
| 4289585 | Wagener et al. | Sep 1981 | A |
| 4296938 | Offermann et al. | Oct 1981 | A |
| 4299666 | Ostmann | Nov 1981 | A |
| 4302935 | Cousimano | Dec 1981 | A |
| 4303615 | Jarmell et al. | Dec 1981 | A |
| 4307673 | Caughey | Dec 1981 | A |
| 4314787 | Kwasnik et al. | Feb 1982 | A |
| 4330372 | Cairns et al. | May 1982 | A |
| 4334963 | Stog | Jun 1982 | A |
| 4336843 | Petty | Jun 1982 | A |
| 4340445 | Kucher et al. | Jul 1982 | A |
| 4342195 | Lo | Aug 1982 | A |
| 4344820 | Thompson | Aug 1982 | A |
| 4344822 | Schwartz et al. | Aug 1982 | A |
| 4353189 | Thiersch et al. | Oct 1982 | A |
| 4366029 | Bixby et al. | Dec 1982 | A |
| 4373244 | Mertens et al. | Feb 1983 | A |
| 4375388 | Hara et al. | Mar 1983 | A |
| 4391674 | Velmin et al. | Jul 1983 | A |
| 4392824 | Struck et al. | Jul 1983 | A |
| 4394217 | Holz et al. | Jul 1983 | A |
| 4395269 | Schuler | Jul 1983 | A |
| 4396394 | Li et al. | Aug 1983 | A |
| 4396461 | Neubaum et al. | Aug 1983 | A |
| 4431484 | Weber et al. | Feb 1984 | A |
| 4439277 | Dix | Mar 1984 | A |
| 4440098 | Adams | Apr 1984 | A |
| 4445977 | Husher | May 1984 | A |
| 4446018 | Cerwick | May 1984 | A |
| 4448541 | Lucas | May 1984 | A |
| 4452749 | Kolvek et al. | Jun 1984 | A |
| 4459103 | Gieskieng | Jul 1984 | A |
| 4469446 | Goodboy | Sep 1984 | A |
| 4474344 | Bennett | Oct 1984 | A |
| 4487137 | Horvat et al. | Dec 1984 | A |
| 4498786 | Ruscheweyh | Feb 1985 | A |
| 4506025 | Kleeb et al. | Mar 1985 | A |
| 4508539 | Nakai | Apr 1985 | A |
| 4527488 | Lindgren | Jul 1985 | A |
| 4564420 | Spindeler et al. | Jan 1986 | A |
| 4568426 | Orlando | Feb 1986 | A |
| 4570670 | Johnson | Feb 1986 | A |
| 4614567 | Stahlherm et al. | Sep 1986 | A |
| 4643327 | Campbell | Feb 1987 | A |
| 4645513 | Kubota et al. | Feb 1987 | A |
| 4655193 | Blacket | Apr 1987 | A |
| 4655804 | Kercheval et al. | Apr 1987 | A |
| 4666675 | Parker et al. | May 1987 | A |
| 4680167 | Orlando | Jul 1987 | A |
| 4704195 | Janicka et al. | Nov 1987 | A |
| 4720262 | Durr et al. | Jan 1988 | A |
| 4724976 | Lee | Feb 1988 | A |
| 4726465 | Kwasnik et al. | Feb 1988 | A |
| 4793931 | Doyle et al. | Dec 1988 | A |
| 4824614 | Jones et al. | Apr 1989 | A |
| 4889698 | Moller et al. | Dec 1989 | A |
| 4919170 | Kallinich et al. | Apr 1990 | A |
| 4929179 | Breidenbach et al. | May 1990 | A |
| 4941824 | Holter et al. | Jul 1990 | A |
| 5052922 | Stokman et al. | Oct 1991 | A |
| 5062925 | Durselen et al. | Nov 1991 | A |
| 5078822 | Hodges et al. | Jan 1992 | A |
| 5087328 | Wegerer et al. | Feb 1992 | A |
| 5114542 | Childress | May 1992 | A |
| 5213138 | Presz | May 1993 | A |
| 5227106 | Kolvek | Jul 1993 | A |
| 5228955 | Westbrook, III | Jul 1993 | A |
| 5234601 | Janke et al. | Aug 1993 | A |
| 5318671 | Pruitt | Jun 1994 | A |
| 5370218 | Johnson et al. | Dec 1994 | A |
| 5423152 | Kolvek | Jun 1995 | A |
| 5447606 | Pruitt | Sep 1995 | A |
| 5480594 | Wilkerson et al. | Jan 1996 | A |
| 5542650 | Abel et al. | Aug 1996 | A |
| 5622280 | Mays et al. | Apr 1997 | A |
| 5659110 | Herden et al. | Aug 1997 | A |
| 5670025 | Baird | Sep 1997 | A |
| 5687768 | Albrecht et al. | Nov 1997 | A |
| 5715962 | McDonnell | Feb 1998 | A |
| 5752548 | Matsumoto et al. | May 1998 | A |
| 5787821 | Bhat et al. | Aug 1998 | A |
| 5810032 | Hong et al. | Sep 1998 | A |
| 5816210 | Yamaguchi | Oct 1998 | A |
| 5857308 | Dismore et al. | Jan 1999 | A |
| 5913448 | Mann et al. | Jun 1999 | A |
| 5928476 | Daniels | Jul 1999 | A |
| 5968320 | Sprague | Oct 1999 | A |
| 6017214 | Sturgulewski | Jan 2000 | A |
| 6059932 | Sturgulewski | May 2000 | A |
| 6139692 | Tamura et al. | Oct 2000 | A |
| 6152668 | Knoch | Nov 2000 | A |
| 6187148 | Sturgulewski | Feb 2001 | B1 |
| 6189819 | Racine | Feb 2001 | B1 |
| 6290494 | Barkdoll | Sep 2001 | B1 |
| 6412221 | Emsbo | Jul 2002 | B1 |
| 6596128 | Westbrook | Jul 2003 | B2 |
| 6626984 | Taylor | Sep 2003 | B1 |
| 6699035 | Brooker | Mar 2004 | B2 |
| 6758875 | Reid et al. | Jul 2004 | B2 |
| 6907895 | Johnson et al. | Jun 2005 | B2 |
| 6946011 | Snyder | Sep 2005 | B2 |
| 6964236 | Schucker | Nov 2005 | B2 |
| 7056390 | Fratello | Jun 2006 | B2 |
| 7077892 | Lee | Jul 2006 | B2 |
| 7314060 | Chen et al. | Jan 2008 | B2 |
| 7331298 | Barkdoll et al. | Feb 2008 | B2 |
| 7433743 | Pistikopoulos et al. | Oct 2008 | B2 |
| 7497930 | Barkdoll et al. | Mar 2009 | B2 |
| 7611609 | Valia et al. | Nov 2009 | B1 |
| 7644711 | Creel | Jan 2010 | B2 |
| 7722843 | Srinivasachar | May 2010 | B1 |
| 7727307 | Winkler | Jun 2010 | B2 |
| 7785447 | Eatough et al. | Aug 2010 | B2 |
| 7803627 | Hodges et al. | Sep 2010 | B2 |
| 7823401 | Takeuchi et al. | Nov 2010 | B2 |
| 7827689 | Crane | Nov 2010 | B2 |
| 7998316 | Barkdoll | Aug 2011 | B2 |
| 8071060 | Ukai et al. | Dec 2011 | B2 |
| 8079751 | Kapila et al. | Dec 2011 | B2 |
| 8080088 | Srinivasachar | Dec 2011 | B1 |
| 8152970 | Barkdoll et al. | Apr 2012 | B2 |
| 8236142 | Westbrook | Aug 2012 | B2 |
| 8266853 | Bloom et al. | Sep 2012 | B2 |
| 8398935 | Howell et al. | Mar 2013 | B2 |
| 8409405 | Kim et al. | Apr 2013 | B2 |
| 8647476 | Kim et al. | Feb 2014 | B2 |
| 8800795 | Hwang | Aug 2014 | B2 |
| 8956995 | Masatsugu et al. | Feb 2015 | B2 |
| 8980063 | Kim et al. | Mar 2015 | B2 |
| 9039869 | Kim | May 2015 | B2 |
| 9057023 | Reichelt et al. | Jun 2015 | B2 |
| 9193915 | West et al. | Nov 2015 | B2 |
| 9243186 | Quanci et al. | Jan 2016 | B2 |
| 9249357 | Quanci et al. | Feb 2016 | B2 |
| 10323192 | Quanci et al. | Jun 2019 | B2 |
| 20020134659 | Westbrook | Sep 2002 | A1 |
| 20020170605 | Shiraishi et al. | Nov 2002 | A1 |
| 20030014954 | Ronning et al. | Jan 2003 | A1 |
| 20030015809 | Carson | Jan 2003 | A1 |
| 20030057083 | Eatough et al. | Mar 2003 | A1 |
| 20050087767 | Fitzgerald et al. | Apr 2005 | A1 |
| 20060102420 | Huber et al. | May 2006 | A1 |
| 20060149407 | Markham et al. | Jul 2006 | A1 |
| 20070116619 | Taylor et al. | May 2007 | A1 |
| 20070251198 | Witter | Nov 2007 | A1 |
| 20080028935 | Andersson | Feb 2008 | A1 |
| 20080179165 | Chen et al. | Jul 2008 | A1 |
| 20080257236 | Green | Oct 2008 | A1 |
| 20080271985 | Yamasaki | Nov 2008 | A1 |
| 20080289305 | Girondi | Nov 2008 | A1 |
| 20090007785 | Kimura et al. | Jan 2009 | A1 |
| 20090152092 | Kim et al. | Jun 2009 | A1 |
| 20090162269 | Barger et al. | Jun 2009 | A1 |
| 20090217576 | Kim et al. | Sep 2009 | A1 |
| 20090283395 | Hippe | Nov 2009 | A1 |
| 20100095521 | Kartal et al. | Apr 2010 | A1 |
| 20100106310 | Grohman | Apr 2010 | A1 |
| 20100113266 | Abe et al. | May 2010 | A1 |
| 20100115912 | Worley | May 2010 | A1 |
| 20100181297 | Whysail | Jul 2010 | A1 |
| 20100196597 | Di Loreto | Aug 2010 | A1 |
| 20100276269 | Schuecker et al. | Nov 2010 | A1 |
| 20100287871 | Bloom et al. | Nov 2010 | A1 |
| 20100300867 | Kim et al. | Dec 2010 | A1 |
| 20100314234 | Knoch et al. | Dec 2010 | A1 |
| 20110048917 | Kim | Mar 2011 | A1 |
| 20110088600 | McRae | Apr 2011 | A1 |
| 20110120852 | Kim | May 2011 | A1 |
| 20110144406 | Masatsugu et al. | Jun 2011 | A1 |
| 20110168482 | Merchant et al. | Jul 2011 | A1 |
| 20110174301 | Haydock et al. | Jul 2011 | A1 |
| 20110192395 | Kim | Aug 2011 | A1 |
| 20110198206 | Kim et al. | Aug 2011 | A1 |
| 20110223088 | Chang et al. | Sep 2011 | A1 |
| 20110253521 | Kim | Oct 2011 | A1 |
| 20110291827 | Baldocchi et al. | Dec 2011 | A1 |
| 20110313218 | Dana | Dec 2011 | A1 |
| 20110315538 | Kim et al. | Dec 2011 | A1 |
| 20120024688 | Barkdoll | Feb 2012 | A1 |
| 20120030998 | Barkdoll et al. | Feb 2012 | A1 |
| 20120125709 | Merchant et al. | May 2012 | A1 |
| 20120152720 | Reichelt et al. | Jun 2012 | A1 |
| 20120180133 | Al-Harbi et al. | Jul 2012 | A1 |
| 20120228115 | Westbrook | Sep 2012 | A1 |
| 20120247939 | Kim et al. | Oct 2012 | A1 |
| 20120305380 | Wang et al. | Dec 2012 | A1 |
| 20130020781 | Kishikawa | Jan 2013 | A1 |
| 20130045149 | Miller | Feb 2013 | A1 |
| 20130216717 | Rago et al. | Aug 2013 | A1 |
| 20130220373 | Kim | Aug 2013 | A1 |
| 20130306462 | Kim et al. | Nov 2013 | A1 |
| 20140033917 | Rodgers et al. | Feb 2014 | A1 |
| 20140039833 | Sharpe, Jr. et al. | Feb 2014 | A1 |
| 20140048402 | Quanci et al. | Feb 2014 | A1 |
| 20140061018 | Sarpen et al. | Mar 2014 | A1 |
| 20140083836 | Quanci et al. | Mar 2014 | A1 |
| 20140182195 | Quanci et al. | Jul 2014 | A1 |
| 20140182683 | Quanci et al. | Jul 2014 | A1 |
| 20140183023 | Quanci et al. | Jul 2014 | A1 |
| 20140183024 | Chun et al. | Jul 2014 | A1 |
| 20140183026 | Quanci et al. | Jul 2014 | A1 |
| 20140208997 | Alferyev et al. | Jul 2014 | A1 |
| 20140224123 | Walters | Aug 2014 | A1 |
| 20140262139 | Choi et al. | Sep 2014 | A1 |
| 20140262726 | West et al. | Sep 2014 | A1 |
| 20150122629 | Freimuth et al. | May 2015 | A1 |
| 20150219530 | Li et al. | Aug 2015 | A1 |
| 20150247092 | Quanci et al. | Sep 2015 | A1 |
| 20150328576 | Quanci et al. | Sep 2015 | A1 |
| 20150287026 | Quanci et al. | Oct 2015 | A1 |
| 20150361346 | West et al. | Dec 2015 | A1 |
| 20150361347 | Ball et al. | Dec 2015 | A1 |
| 20160026193 | Rhodes et al. | Jan 2016 | A1 |
| 20160032193 | Sarpen et al. | Feb 2016 | A1 |
| 20160048139 | Samples et al. | Feb 2016 | A1 |
| 20160060532 | Quanci | Mar 2016 | A1 |
| 20160060533 | Quanci et al. | Mar 2016 | A1 |
| 20160060534 | Quanci et al. | Mar 2016 | A1 |
| 20160060536 | Quanci et al. | Mar 2016 | A1 |
| 20160149944 | Obermeier et al. | May 2016 | A1 |
| 20160319198 | Quanci | Nov 2016 | A1 |
| 20170015908 | Quanci et al. | Jan 2017 | A1 |
| Number | Date | Country |
|---|---|---|
| 1172895 | Aug 1984 | CA |
| 2775992 | May 2011 | CA |
| 2822841 | Jul 2012 | CA |
| 2822857 | Jul 2012 | CA |
| 87212113 | Jun 1988 | CN |
| 87107195 | Jul 1988 | CN |
| 2064363 | Oct 1990 | CN |
| 2139121 | Jul 1993 | CN |
| 1092457 | Sep 1994 | CN |
| 1255528 | Jun 2000 | CN |
| 1270983 | Oct 2000 | CN |
| 2528771 | Feb 2002 | CN |
| 1358822 | Jul 2002 | CN |
| 2521473 | Nov 2002 | CN |
| 1468364 | Jan 2004 | CN |
| 1527872 | Sep 2004 | CN |
| 2668641 | Jan 2005 | CN |
| 1957204 | May 2007 | CN |
| 101037603 | Sep 2007 | CN |
| 101058731 | Oct 2007 | CN |
| 101157874 | Apr 2008 | CN |
| 201121178 | Sep 2008 | CN |
| 101395248 | Mar 2009 | CN |
| 100510004 | Jul 2009 | CN |
| 101486017 | Jul 2009 | CN |
| 201264981 | Jul 2009 | CN |
| 101497835 | Aug 2009 | CN |
| 101509427 | Aug 2009 | CN |
| 102155300 | Aug 2011 | CN |
| 2509188 | Nov 2011 | CN |
| 202226816 | May 2012 | CN |
| 202265541 | Jun 2012 | CN |
| 102584294 | Jul 2012 | CN |
| 202415446 | Sep 2012 | CN |
| 103468289 | Dec 2013 | CN |
| 105189704 | Dec 2015 | CN |
| 106661456 | May 2017 | CN |
| 201729 | Sep 1908 | DE |
| 212176 | Jul 1909 | DE |
| 1212037 | Mar 1966 | DE |
| 3231697 | Jan 1984 | DE |
| 3315738 | Mar 1984 | DE |
| 3329367 | Nov 1984 | DE |
| 3328702 | Feb 1985 | DE |
| 3407487 | Jun 1985 | DE |
| 19545736 | Jun 1997 | DE |
| 19803455 | Aug 1999 | DE |
| 10122531 | Nov 2002 | DE |
| 10154785 | May 2003 | DE |
| 102005015301 | Oct 2006 | DE |
| 102006004669 | Aug 2007 | DE |
| 102006026521 | Dec 2007 | DE |
| 102009031436 | Jan 2011 | DE |
| 102011052785 | Dec 2012 | DE |
| 0126399 | Nov 1984 | EP |
| 0208490 | Jan 1987 | EP |
| 0903393 | Mar 1999 | EP |
| 1538503 | Jun 2005 | EP |
| 2295129 | Mar 2011 | EP |
| 2339664 | Aug 1977 | FR |
| 364236 | Jan 1932 | GB |
| 368649 | Mar 1932 | GB |
| 441784 | Jan 1936 | GB |
| 606340 | Aug 1948 | GB |
| 611524 | Nov 1948 | GB |
| 725865 | Mar 1955 | GB |
| 871094 | Jun 1961 | GB |
| 923205 | May 1963 | GB |
| S50148405 | Nov 1975 | JP |
| S59019301 | Feb 1978 | JP |
| 54054101 | Apr 1979 | JP |
| S5453103 | Apr 1979 | JP |
| 57051786 | Mar 1982 | JP |
| 57051787 | Mar 1982 | JP |
| 57083585 | May 1982 | JP |
| 57090092 | Jun 1982 | JP |
| 58091788 | May 1983 | JP |
| 59051978 | Mar 1984 | JP |
| 59053589 | Mar 1984 | JP |
| 59071388 | Apr 1984 | JP |
| 59108083 | Jun 1984 | JP |
| 59145281 | Aug 1984 | JP |
| 60004588 | Jan 1985 | JP |
| 61106690 | May 1986 | JP |
| 62011794 | Jan 1987 | JP |
| 62285980 | Dec 1987 | JP |
| 01103694 | Apr 1989 | JP |
| 01249886 | Oct 1989 | JP |
| H0319127 | Mar 1991 | JP |
| 03197588 | Aug 1991 | JP |
| 04159392 | Jun 1992 | JP |
| H04178494 | Jun 1992 | JP |
| H0649450 | Feb 1994 | JP |
| H0654753 | Jul 1994 | JP |
| 06264062 | Sep 1994 | JP |
| 07188668 | Jul 1995 | JP |
| 07216357 | Aug 1995 | JP |
| H07204432 | Aug 1995 | JP |
| H08104875 | Apr 1996 | JP |
| 08127778 | May 1996 | JP |
| H10273672 | Oct 1998 | JP |
| H11-131074 | May 1999 | JP |
| 2000204373 | Jul 2000 | JP |
| 2001200258 | Jul 2001 | JP |
| 2002106941 | Apr 2002 | JP |
| 2003041258 | Feb 2003 | JP |
| 2003071313 | Mar 2003 | JP |
| 2003292968 | Oct 2003 | JP |
| 2003342581 | Dec 2003 | JP |
| 2005503448 | Feb 2005 | JP |
| 2005263983 | Sep 2005 | JP |
| 2006188608 | Jul 2006 | JP |
| 2007063420 | Mar 2007 | JP |
| 4101226 | Jun 2008 | JP |
| 2008231278 | Oct 2008 | JP |
| 2009073864 | Apr 2009 | JP |
| 2009073865 | Apr 2009 | JP |
| 2009144121 | Jul 2009 | JP |
| 2010229239 | Oct 2010 | JP |
| 2010248389 | Nov 2010 | JP |
| 2012102302 | May 2012 | JP |
| 2013006957 | Jan 2013 | JP |
| 2013510910 | Mar 2013 | JP |
| 2013189322 | Sep 2013 | JP |
| 2014040502 | Mar 2014 | JP |
| 1019960008754 | Oct 1996 | KR |
| 1019990054426 | Jul 1999 | KR |
| 20000042375 | Jul 2000 | KR |
| 100296700 | Oct 2001 | KR |
| 1020050053861 | Jun 2005 | KR |
| 100737393 | Jul 2007 | KR |
| 100797852 | Jan 2008 | KR |
| 1020110010452 | Feb 2011 | KR |
| 101314288 | Apr 2011 | KR |
| 20130050807 | May 2013 | KR |
| 101318388 | Oct 2013 | KR |
| 2083532 | Jul 1997 | RU |
| 2441898 | Feb 2012 | RU |
| 1535880 | Jan 1990 | SU |
| 201241166 | Oct 2012 | TW |
| 201245431 | Nov 2012 | TW |
| 505080 | Oct 2002 | UA |
| WO9012074 | Oct 1990 | WO |
| WO2005023649 | Mar 2005 | WO |
| WO2005115583 | Dec 2005 | WO |
| WO2007103649 | Sep 2007 | WO |
| WO2008034424 | Mar 2008 | WO |
| WO2011000447 | Jan 2011 | WO |
| WO2012029979 | Mar 2012 | WO |
| WO2012031726 | Mar 2012 | WO |
| WO2013023872 | Feb 2013 | WO |
| WO2010107513 | Sep 2013 | WO |
| WO2014021909 | Feb 2014 | WO |
| WO2014043667 | Mar 2014 | WO |
| WO2014105064 | Jul 2014 | WO |
| WO2014153050 | Sep 2014 | WO |
| WO2016004106 | Jan 2016 | WO |
| Entry |
|---|
| Forum post by user “wireaddict” on AllAboutCircuits.com message board titled “What is dead-band control”, Feb. 8, 2007, avilable online at: https://forum.allaboutcircuits.com/threads/what-is-dead-band-control.4728/ (Year: 2007). |
| Astrom, Karl Johan, Richard, Murray M., “Feedback Systems: An Introduction for Scientists and Engineers”, Sep. 16, 2006, Available Online at: http://people.duke.edu/˜hpgavin/SystemID/References/Astrom-Feedback-2006.pdf (Year: 2006). |
| B. Joseph, “A tutorial on inferential control and its applications,” Proceedings of the 1999 American Control Conference (Cat. No. 99CH36251), San Diego, CA, 1999, pp. 3106-3118 vol.5. doi: 10.1109/ACC.1999.782334 (Year: 1999). |
| U.S. Appl. No. 15/392,942, filed Dec. 28, 2016, Quanci et al. |
| Canadian Office Action in Canadian Application No. 2,881,879, dated Oct. 13, 2016, 3 pages. |
| Chinese Office Action in Chinese Application No. 201380054404.2, dated Sep. 14, 2016. |
| U.S. Appl. No. 15/322,176, filed Dec. 27, 2016, West et al. |
| U.S. Appl. No. 15/443,246, filed Feb. 27, 2017, Quanci et al. |
| U.S. Appl. No. 15/511,036, filed Mar. 14, 2017, West et al. |
| Beckman et al., “Possibilities and limits of cutting back coking plant output,” Stahl Und Eisen, Verlag Stahleisen, Dusseldorf, DE, vol. 130, No. 8, Aug. 16, 2010, pp. 57-67. |
| Kochanski et al., “Overview of Uhde Heat Recovery Cokemaking Technology,” AISTech Iron and Steel Technology Conference Proceedings, Association for Iron and Steel Technology, U.S., vol. 1, Jan. 1, 2005, pp. 25-32. |
| U.S. Appl. No. 14/952,267, filed Nov. 25, 2015, Quanci et al. |
| U.S. Appl. No. 14/959,450, filed Dec. 4, 2015, Quanci et al. |
| U.S. Appl. No. 14/983,837, filed Dec. 30, 2015, Quanci et al. |
| U.S. Appl. No. 14/984,489, filed Dec. 30, 2015, Quanci et al. |
| U.S. Appl. No. 14/986,281, filed Dec. 31, 2015, Quanci et al. |
| U.S. Appl. No. 14/987,625, filed Jan. 4, 2016, Quanci et al. |
| U.S. Appl. No. 15/014,547, filed Feb. 3, 2016, Choi et al. |
| ASTM D5341-99(2010)e1, Standard Test Method for Measuring Coke Reactivity Index (CRI) and Coke Strength After Reaction (CSR), ASTM International, West Conshohocken, PA, 2010. |
| Basset, et al., “Calculation of steady flow pressure loss coefficients for pipe junctions,” Proc Instn Mech Engrs., vol. 215, Part C. IMechIE 2001. |
| Chinese Office Action in Chinese Application No. 201380054404.2, dated Mar. 21, 2016. |
| Clean coke process: process development studies by USS Engineers and Consultants, Inc., Wisconsin Tech Search, request date Oct. 5, 2011, 17 pages. |
| Costa, et al., “Edge Effects on the Flow Characteristics in a 90 deg Tee Junction,” Transactions of the ASME, Nov. 2006, vol. 128, pp. 1204-1217. |
| Crelling, et al., “Effects of Weathered Coal on Coking Properties and Coke Quality”, Fuel, 1979, vol. 58, Issue 7, pp. 542-546. |
| Database WPI, Week 199115, Thomson Scientific, Lond, GB; AN 1991-107552. |
| Diez, et al., “Coal for Metallurgical Coke Production: Predictions of Coke Quality and Future Requirements for Cokemaking”, International Journal of Coal Geology, 2002, vol. 50, Issue 1-4, pp. 389-412. |
| Extended Examination Report for European Patent Application No. 13829740.3, dated Feb. 23, 2016, 10 pages. |
| International Search Report and Written Opinion of International Application No. PCT/US2013/054703; dated Nov. 21, 2013; 11 pages. |
| JP 03-197588, Inoue Keizo et al., Method and Equipment for Boring Degassing Hole in Coal Charge in Coke Oven, Japanese Patent (Abstract Only) Aug. 28, 1991. |
| JP 04-159392, Inoue Keizo et al., Method and Equipment for Opening Hole for Degassing of Coal Charge in Coke Oven, Japanese Patent (Abstract Only) Jun. 2, 1992. |
| Rose, Harold J., “The Selection of Coals for the Manufacture of Coke,” American Institute of Mining and Metallurgical Engineers, Feb. 1926, 8 pages. |
| Waddell, et al., “Heat-Recovery Cokemaking Presentation,” Jan. 1999, pp. 1-25. |
| Westbrook, “Heat-Recovery Cokemaking at Sun Coke,” AISE Steel Technology, Pittsburg, PA, vol. 76, No. 1, Jan. 1999, pp. 25-28. |
| Yu et al., “Coke Oven Production Technology,” Lianoning Science and Technology Press, first edition, Apr. 2014, pp. 356-358. |
| “Resources and Utilization of Coking Coal in China,” Mingxin Shen ed., Chemical Industry Press, first edition, Jan. 2007, pp. 242-243, 247. |
| U.S. Appl. No. 15/614,525, filed Jun. 5, 2017, Quanci et al. |
| Examination Report in European Application No. 13829740.3, dated Apr. 4, 2017. |
| “Conveyor Chain Designer Guild”, Mar. 27, 2014 (date obtained from wayback machine), Renold.com, Section 4, available online at: http://www.renold/com/upload/renoldswitzerland/conveyor_chain_-_designer_guide.pdf. |
| Practical Technical Manual of Refractories, Baoyu Hu, etc., Bejing: Metallurgical Industry Press, Chapter 6; 2004, 6-30. |
| Refractories for Ironmaking and Steelmaking: A History of Battles over High Temperatures; Kyoshi Sugita (Japan, Shaolin Zhang), 1995, p. 160, 2004, 2-29. |
| “Middletown Coke Company HRSG Maintenance BACT Analysis Option 1—Individual Spray Quenches Sun Heat Recovery Coke Facility Process Flow Diagram Middletown Coke Company 100 Oven Case #1-24.5 VM”, (Sep. 1, 2009), URL: http://web.archive.org/web/20090901042738/http://epa.ohio.gov/portals/27/transfer/ptiApplication/mcc/new/262504.pdf, (Feb. 12, 2016), XP055249803 [X] 1-13 * p. 7 * * pp. 8-11 *. |
| Walker D N et al, “Sun Coke Company's heat recovery cokemaking technology high coke quality and low environmental impact”, Revue De Metallurgie—Cahiers D'Informations Techniques, Revue De Metallurgie. Paris, FR, (Mar. 1, 2003), vol. 100, No. 3, ISSN 0035-1563, p. 23. |
| Bloom, et al., “Modular cast block—The future of coke oven repairs,” Iron & Steel Technol, AIST, Warrendale, PA, vol. 4, No. 3, Mar. 1, 2007, pp. 61-64. |
| U.S. Appl. No. 16/026,363, filed Jul. 3, 2018, Chun et al. |
| U.S. Appl. No. 16/047,198, filed Jul. 27, 2018, Quanci et al. |
| U.S. Appl. No. 15/987,860, filed May 23, 2018, Crum et al. |
| U.S. Appl. No. 16/000,516, filed Jun. 5, 2018, Quanci. |
| Boyes, Walt. (2003), Instrumentation Reference Book (3rd Edition)—34.7.4.6 Infrared and Thermal Cameras, Elsevier. Online version available at: https://app.knovel.com/hotlink/pdf/id:kt004QMGV6/instrumentation-reference-2/ditigal-video. |
| Kerlin, Thomas (1999), Practical Thermocouple Thermometry—1.1 The Thermocouple. ISA. Online version available at https:app.knovel.com/pdf/id:kt007XPTM3/practical-thermocouple/the-thermocouple. |
| Madias, et al., “A review on stamped charging of coals” (2013). Available at https://www.researchgate.net/publicatoin/263887759_A_review_on_stamped_charging_of_coals. |
| Metallurgical Coke MSDS, ArcelorMittal, May 30, 2011, available online at http://dofasco.arcelormittal.com/-/media/Files/A/Arcelormittal-Canada/material-safety/metallurgical-coke.pdf. |
| Chinese Office Action in Chinese Application No. 201610146824.9; dated May 3, 2018; 5 pages. |
| U.S. Appl. No. 13/830,971, filed Mar. 14, 2013, titled Non-Perpendicular Connections Between Coke Oven Uptakes and a Hot Common Tunnel, and Associated Systems and Methods now U.S. Pat. No. 10,047,295. |
| U.S. Appl. No. 16/026,363, filed Jul. 3, 2018, title Non-Perpendicular Connections Between Coke Oven Uptakes and a Hot Common Tunnel, and Associated Systems and Methods. |
| U.S. Appl. No. 14/952,267, filed Nov. 25, 2015, titled Systems and Methods for Improving Quenched Coke Recovery. |
| U.S. Appl. No. 15/830,320, filed Dec. 4, 2017, titled Systems and Methods for Improving Quenched Coke Recovery. |
| U.S. Appl. No. 14/959,450, filed Dec. 4, 2015, titled Coke Plant Including Exhaust Gas Sharing, now U.S. Pat. No. 10,041,002. |
| U.S. Appl. No. 13/598,394, now U.S. Pat. No. 9,169,439, filed Aug. 29, 2012, titled Method and Apparatus for Testing Coal Coking Properties. |
| U.S. Appl. No. 14/865,851, filed Sep. 25, 2015, titled Method and Apparatus for Testing Coal Coking Properties, now U.S. Pat. No. 10,053,627. |
| U.S. Appl. No. 14/983,837, filed Dec. 30, 2015, titiled Multi-Modal Beds of Coking Material. |
| U.S. Appl. No. 14/986,281, filed Dec. 31, 2015, titled Multi-Modal Beds of Coking Material. |
| U.S. Appl. No. 14,839,493, filed Aug. 28, 2015, titled Method and System for Optimizing Coke Plant Operation and Output. |
| U.S. Appl. No. 14/839,551, filed Aug. 28, 2015, titled Burn Profiles for Coke Operations. |
| U.S. Appl. No. 15/614,525, filed Jun. 5, 2017, titled Methods and Systems for Automatically Generating a Remedial Action in an Industrial Facility. |
| U.S. Appl. No. 15/987,860, filed May 23, 2018, titled System and Method for Repairing a Coke Oven. |
| U.S. Appl. No. 08/914,140, filed on Aug. 19, 1997, now U.S. Pat. No. 5,928,476, titled Nonrecovery Coke Oven Door. |
| U.S. Appl. No. 13/830,971, filed Mar. 14, 2013, titled Non-Perpendicular Connections Between Coke Oven Uptakes and a Hot Common Tunnel, and Associated Systems and Methods. |
| U.S. Appl. No. 14/959,450, filed Dec. 4, 2015, titled Coke Plant Including Exhaust Gas Sharing. |
| U.S. Appl. No. 14/865,581, filed Sep. 25, 2015, titled Method and Apparatus for Testing Coal Coking Properties. |
| U.S. Appl. No. 15/443,246, filed Feb. 27, 2017, titled Coke Oven Charging System. |
| U.S. Appl. No. 14/987,625, filed on Jan. 4, 2016, titled Integrated Coke Plant Automation and Optimization Using Advanced Control and Optimization Techniques. |
| U.S. Appl. No. 16/251,352, filed Jan. 18, 2019, Quanci et al. |
| U.S. Appl. No. 13/631,215, filed Sep. 28, 2012, titled Methods and Handling Coal Processing Emissions and Associated Systems and Devices. |
| U.S. Appl. No. 14/839,588, filed Aug. 28, 2015, titled Method and System for Optimizing Coke Plant Operation and Output. |
| U.S. Appl. No. 14/655,204, filed June 24, 2015, titled Systems and Methods for Removing Mercury From Emissions. |
| U.S. Appl. No. 14/839,493, filed Aug. 28, 2015, now U.S. Pat. No. 10,233,392, titled Method and System for Optimizing Coke Plant Operation and Output. |
| U.S. Appl. No. 13/588,996, now U.S. Pat. No. 9,243,186, filed August 17, 2012, titled Coke Plant Including Exhaust Gas Sharing. |
| U.S. Appl. No. 13/631,215, filed Sep. 28, 2012, titled Methods for Handling Coal Processing Emissions and Associated Systems and Devices. |
| Astrom, et al., “Feedback Systems: An Introduction for Scientists and Engineers,” Sep. 16, 2006, available on line at http://people/duke.edu/-hpgavin/SystemID/References/Astrom-Feedback-2006.pdf ; 404 pages. |
| Industrial Furnace Design Handbook, Editor-in-Chief: First Design Institute of First Ministry of Machinery Industry, Beijing: Mechanical Industry Press, pp. 180-183, Oct. 1981. |
| “What is dead-band control,” forum post by user “wireaddict” on AllAboutCircuits.com message board, Feb. 8, 2007, accessed Oct. 24, 2018 at https:/forum.allaboutcircuits.com/threads/what-is-dead-band-control.4728/; 8 pages. |
| U.S. Appl. No. 16/428,014, filed May 31, 2019, Quanci et al. |
| Knoerzer et al. “Jewell-Thompson Non-Recovery Cokemaking”, Steel Times, Fuel & Metallurgical Journals Ltd. London, GB, vol. 221, No. 4, Apr. 1, 1993, pp. 172-173,184. |
| U.S. Appl. No. 07/587,742, filed Sep. 25, 1990, now U.S. Pat. No. 5,114,542, titled Nonrecovery Coke Oven Battery and Method of Operation. |
| U.S. Appl. No. 07/878,904, filed May 6, 1992, now U.S. Pat. No. 5,318,671, titled Method of Operation of Nonrecovery Coke Oven Battery. |
| U.S. Appl. No. 09/783,195, filed Feb. 14, 2001, now U.S. Pat. No. 6,596,128, titled Coke Oven Flue Gas Sharing. |
| U.S. Appl. No. 07/886,804, filed May 22, 1992, now U.S. Pat. No. 5,228,955, titled High Strength Coke Oven Wall Having Gas Flues Therein. |
| U.S. Appl. No. 08/059,673, filed May 12, 1993, now U.S. Pat. No. 5,447,606, titled Method of and Apparatus for Capturing Coke Oven Charging Emissions. |
| U.S. Appl. No. 08/914,140, filed Aug. 19, 1997, now U.S. Pat. No. 5,928,476, titled Nonrecovery Coke Oven Door. |
| U.S. Appl. No. 09/680,187, filed Oct. 5, 2000, now U.S. Pat. No. 6,290,494, titled Method and Apparatus for Coal Coking. |
| U.S. Appl. No. 10/933,866, filed Sep. 3, 2004, now U.S. Pat. No. 7,331,298, titled Coke Oven Rotary Wedge Door Latch. |
| U.S. Appl. No. 11/424,566, filed Jun. 16, 2006, now U.S. Pat. No. 7,497,930, titled Method and Apparatus for Compacting Coal for a Coal Coking Process. |
| U.S. Appl. No. 12/405,269, filed Mar. 17, 2009, now U.S. Pat. No. 7,998,316, titled Flat Push Coke Wet Quenching Apparatus and Process. |
| U.S. Appl. No. 13/205,960, filed Aug. 9, 2011, now U.S. Pat. No. 9,321,965, titled Flat Push Coke Wet Quenching Apparatus and Process. |
| U.S. Appl. No. 11/367,236, filed Mar. 3, 2006, now U.S. Pat. No. 8,152,970, titled Method and Apparatus for Producing Coke. |
| U.S. Appl. No. 12/403,391, filed Mar. 13, 2009, now U.S. Pat. No. 8,172,930, titled Cleanable in Situ Spark Arrestor. |
| U.S. Appl. No. 12/849,192, filed Aug. 3, 2010, now U.S. Pat. No. 9,200,225, titled Method and Apparatus for Compacting Coal for a Coal Coking Process. |
| U.S. Appl. No. 13/631,215, filed Sep. 28, 2012, now U.S. Pat. No. 9,683,740, titled Methods for Handling Coal Processing Emissions and Associated Systems and Devices. |
| U.S. Appl. No. 13/730,692, filed Dec. 28, 2012, now U.S. Pat. No. 9,193,913, titled Reduced Output Rate Coke Oven Operation With Gas Sharing Providing Extended Process Cycle. |
| U.S. Appl. No. 14/921,723, filed Oct. 23, 2015, titled Reduced Output Rate Coke Oven Operation With Gas Sharing Providing Extended Process Cycle. |
| U.S. Appl. No. 14/655,204, filed Jun. 24, 2015, titled Systems and Methods for Removing Mercury From Emissions. |
| U.S. Appl. No. 16/000,516, filed Jun. 5, 2018, titled Systems and Methods for Removing Mercury From Emissions. |
| U.S. Appl. No. 13/830,971, filed Mar. 14, 2013, now U.S. Pat. No. 10,047,296, titled Non-Perpendicular Connections Between Coke Oven Uptakes and a Hot Common Tunnel, and Associated Systems and Methods, now U.S. Pat. No. 10,047,295. |
| U.S. Appl. No. 16/026,363, filed Jul. 3, 2018, titled Non-Perpendicular Connections Between Coke Oven Uptakes and a Hot Common Tunnel, and Associated Systems and Methods. |
| U.S. Appl. No. 13/730,796, filed Dec. 28, 2012, titled Methods and Systems for Improved Coke Quenching. |
| U.S. Appl. No. 13/730,598, filed Dec. 28, 2012, now U.S. Pat. No. 9,238,778, titled Systems and Methods for Improving Quenched Coke Recovery. |
| U.S. Appl. No. 14/952,267, filed Nov. 25, 2015, now U.S. Pat. No. 9,862,888, titled Systems and Methods for Improving Quenched Coke Recovery. |
| U.S. Appl. No. 15/830,320, filed Dec. 4, 2017, now U.S. Pat. No. 10,323,192, titled Systems and Methods for Improving Quenched Coke Recovery. |
| U.S. Appl. No. 13/730,735, filed Dec. 28, 2012, now U.S. Pat. No, 9,273,249, titled Systems and Methods for Controlling Air Distribution in a Coke Oven. |
| U.S. Appl. No. 14/655,013, filed Jun. 23, 2015, titled Vent Stack Lids and Associated Systems and Methods. |
| U.S. Appl. No. 13/843,166, now U.S. Pat. No. 9,273,250, filed Mar. 15, 2013, titled Methods and Systems for Improved Quench Tower Design. |
| U.S. Appl. No. 15/014,547, filed Feb. 3, 2016, titled Methods and Systems for Improved Quench Tower Design. |
| U.S. Appl. No. 14/655,003, filed Jun. 23, 2015, titled Systems and Methods for Maintaining a Hot Car in a Coke Plant. |
| U.S. Appl. No. 13/829,588, now U.S. Pat. No. 9,193,915, filed Mar. 14, 2013, titled Horizontal Heat Recovery Coke Ovens Having Monolith Crowns. |
| U.S. Appl. No. 15/322,176, filed Dec. 27, 2016, titled Horizontal Heat Recovery Coke Ovens Having Monolith Crowns. |
| U.S. Appl. No. 15/511,036, filed Mar. 14, 2017, titled Coke Ovens Having Monolith Component Construction. |
| U.S. Appl. No. 13/589,009, filed Aug. 17, 2012, titled Automatic Draft Control System for Coke Plants. |
| U.S. Appl. No. 13/588,996, now U.S. Pat. No. 9,243,186, filed Aug. 17, 2012, titled Coke Plant Including Exhaust Gas Sharing. |
| U.S. Appl. No. 14/959,450, filed Dec. 4, 2015, now U.S. Pat. No. 10,041,002, titled Coke Plant Including Exhaust Gas Sharing, now U.S. Pat. No. 10,041,002. |
| U.S. Appl. No. 16/047,198, filed Jul. 27, 2018, titled Coke Plant Including Exhaust Gas Sharing. |
| U.S. Appl. No. 13/589,004, now U.S. Pat. No. 9,249,357, filed Aug. 17, 2012, titled Method and Apparatus for Volatile Matter Sharing in Stamp-Charged Coke Ovens. |
| U.S. Appl. No. 13/730,673, filed Dec. 28, 2012, titled Exhaust Flow Modifier, Duct Intersection Incorporating the Same, and Methods Therefor. |
| U.S. Appl. No. 15/281,891, filed Sep. 30, 2016, titled Exhaust Flow Modifier, Duck Intersection Incorporating the Same, and Methods Therefor. |
| U.S. Appl. No. 13/598,394, now U.S. Pat. No. 9,169,439, filed Aug. 29, 2012, titled Method and Appartus for Testing Coal Coking Properties. |
| U.S. Appl. No. 14/865,581, filed Sep. 25, 2015, now U.S. Pat. No. 10,053,627, titled Method and Apparatus for Testing Coal Coking Properties, now U.S. Pat. No. 10,053,627. |
| U.S. Appl. No. 14/839,384, filed Aug. 28, 2015, titled Coke Oven Charging System. |
| U.S. Appl. No. 15/443,246, now U.S. Pat. No. 9,976,089, filed Feb. 27, 2017, titled Coke Oven Charging System. |
| U.S. Appl. No. 14/587,670, filed Dec. 31, 2014, titled Methods for Decarbonizing Coking Ovens, and Associated Systems and Devices. |
| U.S. Appl. No. 14/984,489, filed Dec. 30, 2015, titled Multi-Modal Beds of Coking Material. |
| U.S. Appl. No. 14/983,837, filed Dec. 30, 2015, titled Multi-Modal Beds of Coking Material. |
| U.S. Appl. No. 14/986,281, filed Dec. 31, 2015, title Multi-Modal Beds of Coking Material. |
| U.S. Appl. No. 14/987,625, filed Jan. 4, 2016, titled Integrated Coke Plant Automation and Optimization Using Advanced Control and Optimization Techniques. |
| U.S. Appl. No. 14/839,493, filed Aug. 28, 2015, now U.S. Pat. No. 10,233,392, title Method and System for Optimizing Coke Plant Operation and Output. |
| U.S. Appl. No. 16/251,352, filed Jan. 18, 2019, titled Method and System for Optimizing Coke Plant Operation and Output. |
| U.S. Appl. No. 14/839,551, filed Aug. 28, 2015, now U.S. Pat. No. 10,308,876, titled Burn Profiles for Coke Operations. |
| U.S. Appl. No. 16/428,014, filed May 31, 2019, titled Improved Burn Profiles for Coke Operations. |
| U.S. Appl. No. 14/839,588, filed Aug. 28, 2015, now U.S. Pat. No. 9,708,542, titled Method and System for Optimizing Coke Plant Operation and Output. |
| U.S. Appl. No. 15/392,942, filed Dec. 28, 2016, titled Method and System for Dynamically Charging a Coke Oven. |
| U.S. Appl. No. 15/614,525, filed Jun. 5, 2017, title Methods and Systems for Automatically Generating a Remedial Action in an Industrial Facility. |
| U.S. Appl. No. 15/987,860, filed May 23, 2018, title System and Method for Repairing a Coke Oven. |
| U.S. Appl. No. 16/704,689, filed Dec. 5, 2019, West et al. |
| U.S. Appl. No. 16/729,036, filed Dec. 27, 2019 Quanci et at. |
| U.S. Appl. No. 16/729,053, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,057, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,068, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,122, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,129, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,157, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,170, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,201, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,212, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/729,219, filed Dec. 27, 2019, Quanci et at. |
| U.S. Appl. No. 16/735,103, filed Jan. 6, 2020, Quanci et al. |
| Chinese Notice of Reexamination in Chinese Application No. 201280077986.1; dated Nov. 21, 2019; 14 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20160319197 A1 | Nov 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 13589009 | Aug 2012 | US |
| Child | 15139568 | US |
