Patent Application
20250101310
The present disclosure relates to coke ovens, and more particularly, to a system and method for monitoring and manipulating a coke oven battery to control its exhaust stack opacity and to maintain battery temperatures to increase coke oven battery energy efficiency and structural longevity.
Coke is typically produced by heating coal in a coke oven. Coke ovens are assembled together in a slotted arrangement in a coke oven battery, which may have anywhere from 40 to over 100 side-by-side cooking or coking chambers or ovens separated from each other by heating walls. Gas is burned within the walls to heat the coal arranged in the ovens. The floor bricks of each oven rest upon corbels. Below the corbels is an area called the regenerator, which acts at least in part as a heat-exchanger. The regenerator is filled with bricks that have a relatively large amount of surface area per unit volume, generally due to slots formed in the bricks. In the regenerator, exhaust waste heat is used to pre-heat incoming combustion air as well as cool the exhaust waste prior to discharge. The regenerator supports the corbels. In turn, the corbels support the coke oven floor bricks and the heating walls. The heating walls, floor bricks, and corbels have traditionally been made of silica brick due to its high heat conductivity, high temperature resistance, and stable thermal expansion characteristics at operating temperature.
Due to current regulations, for example the 1990 Clean Air Act Amendment, waste exhaust from coke ovens being expelled into the air is monitored, and failure to comply with regulations can be punishable by significant fines. Compliance with such regulations causes operators to manipulate the coke oven battery in a manner that is detrimental to both the energy efficiency and the longevity of the coke oven battery, eventually leading to failure of coke oven components, such as the heating walls.
Thus, there has been a long-felt need for a system and method of monitoring and manipulating a coke oven or coke oven battery that improves compliance with opacity regulations but does not jeopardize the energy efficiency or longevity of the coke oven walls and/or of the whole battery.
The present disclosure is directed to one or more exemplary embodiments of a coke oven battery modulation system.
In an exemplary embodiment, the coke oven battery modulation system comprises a coke oven battery, a combustion air supply fluidly connected to the coke oven battery via a first conduit, a fuel supply fluidly connected to the coke oven battery via a second conduit, a stack fluidly connected to the coke oven battery via a third conduit, the stack forming a fluid flow including a flow rate, a damper arranged in the third conduit, a first actuator operatively arranged to adjust the damper, at least one sensor, and a controller operatively arranged to receive data from the at least one sensor and communicate with the first actuator to adjust the damper.
In an exemplary embodiment, the at least one sensor comprises a temperature sensor. In an exemplary embodiment, the temperature sensor is operatively arranged to detect a temperature of the fluid flow. In an exemplary embodiment, the temperature sensor is operatively arranged to detect a temperature of at least one component of the coke oven battery. In an exemplary embodiment, the at least one sensor comprises an opacity monitor operatively arranged to detect an opacity of the stack. In an exemplary embodiment, the at least one sensor comprises a pressure sensor operatively arranged to detect a pressure (or draft) of the fluid flow. In an exemplary embodiment, the at least one sensor comprises an oxygen sensor operatively arranged to detect an oxygen level in the fluid flow. In an exemplary embodiment, the at least one sensor comprises an opacity sensor, a temperature sensor arranged in the third conduit, a pressure (or draft) sensor arranged in the third conduit, and an oxygen sensor arranged in the third conduit. In an exemplary embodiment, a draft sensor measures the amount of vacuum or suction pressure generated by air moving or expanding through an air duct, ventilation shaft, flue, or chimney.
In an exemplary embodiment, the second conduit comprises a valve, the valve being connected to a second actuator, the second actuator is operatively arranged to adjust the valve, and the controller is operatively arranged to receive data from the at least one sensor and communicate with the second actuator to adjust the valve. In an exemplary embodiment, the at least one sensor comprises a pressure sensor operatively arranged to detect the pressure of the fuel supply. In an exemplary embodiment, the fluid flow includes exhaust gasses flowing from the coke oven battery to an outlet of the stack. In an exemplary embodiment, the fluid flow includes fluid flowing from the combustion air supply, through the coke oven battery, and to an outlet of the stack.
The present disclosure is directed to one or more exemplary embodiments of method for modulating a coke oven battery system.
In an exemplary embodiment, the method for monitoring a coke oven battery system including a coke oven battery, a stack, a fuel supply, and a combustion air supply comprises receiving an input from one or more sensors, determining that an opacity of the stack is less than a first predetermined threshold, and decreasing a flow rate of fluid through the stack and/or increasing the fuel supply to the coke oven battery.
In an exemplary embodiment, the method further comprises determining that the opacity of the stack is greater than or equal to the first predetermined threshold, determining that the opacity of the stack is greater than a second predetermined threshold, the second predetermined threshold being greater than the first predetermined threshold, and determining if an oxygen level of exhaust fluid from the coke oven battery is less than a third predetermined threshold. In an exemplary embodiment, the method further comprises determining that the oxygen level of exhaust fluid from the coke oven battery is less than the third predetermined threshold, and decreasing the fuel supply to the coke oven.
In an exemplary embodiment, the method further comprises determining that the opacity of the stack is greater than or equal to the first predetermined threshold, determining that the opacity of the stack is greater than a second predetermined threshold, the second predetermined threshold being greater than the first predetermined threshold, and determining if a temperature of the exhaust fluid from the coke oven battery is greater than a fourth predetermined threshold. In an exemplary embodiment, the method further comprises determining that the temperature of exhaust fluid from the coke oven battery is greater than the fourth predetermined threshold, and increasing the fluid flow rate of the fluid through the stack.
In an exemplary embodiment, the step of determining that the opacity of the stack is less than a first predetermined threshold comprises receiving opacity data from the one or more sensors, and calculating the opacity as a rolling average of the opacity data. In an exemplary embodiment, the step of determining that the opacity of the stack is less than a first predetermined threshold comprises receiving opacity data from the one or more sensors, removing opacity readings from the opacity data that exceed a fifth predetermined threshold, and calculating the opacity as a rolling average of the opacity data without the opacity readings that exceed the fifth predetermined threshold. In an exemplary embodiment, the method further comprises calculating a rolling average level of oxygen of exhaust fluid from the coke oven battery, and a rolling average temperature of exhaust fluid from the coke oven battery.
These and other objects, features, and advantages of the present disclosure will become readily apparent upon a review of the following detailed description of the disclosure, in view of the drawings and appended claims.
The accompanying drawings are incorporated herein as part of the specification. The drawings described herein illustrate embodiments of the presently disclosed subject matter and are illustrative of selected principles and teachings of the present disclosure, in which corresponding reference symbols indicate corresponding parts. However, the drawings do not illustrate all possible implementations of the presently disclosed subject matter and are not intended to limit the scope of the present disclosure in any way.
It is to be understood that the invention may assume various alternative orientations and step sequences, except where expressly specified to the contrary. It is also to be understood that the specific assemblies and systems illustrated in the attached drawings and described in the following specification are simply exemplary embodiments of the inventive concepts defined herein. Hence, specific dimensions, directions, or other physical characteristics relating to the embodiments disclosed are not to be considered as limiting, unless expressly stated otherwise. Also, although they may not be, like elements in various embodiments described herein may be commonly referred to with like reference numerals within this section of the application.
Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the claims.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the example embodiments.
Where used herein, the terms “first,” “second,” and so on, do not necessarily denote any ordinal, sequential, or priority relation, but are simply used to more clearly distinguish one element or set of elements from another, unless specified otherwise.
Where used herein, the term “about” when applied to a value is intended to mean within the tolerance range of the equipment used to produce the value, or, in some examples, is intended to mean plus or minus 10%, or plus or minus 5%, or plus or minus 1%, unless otherwise expressly specified.
It should be appreciated that the term “substantially” is synonymous with terms such as “nearly,” “very nearly,” “about,” “approximately,” “around,” “bordering on,” “close to,” “essentially,” “in the neighborhood of,” “in the vicinity of,” etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term “proximate” is synonymous with terms such as “nearby,” “close,” “adjacent,” “neighboring,” “immediate,” “adjoining,” etc., and such terms may be used interchangeably as appearing in the specification and claims. The term “substantially” is intended to mean values within ten percent of the specified value.
Where used herein, the term “exemplary” is intended to mean “an example of,” “serving as an example,” or “illustrative,” and does not denote any preference or requirement with respect to a disclosed aspect or embodiment.
It should be understood that use of “or” in the present application is with respect to a “non-exclusive” arrangement, unless stated otherwise. For example, when saying that “item x is A or B,” it is understood that this can mean one of the following: (1) item x is only one or the other of A and B; (2) item x is both A and B. Alternately stated, the word “or” is not used to define an “exclusive or” arrangement. For example, an “exclusive or” arrangement for the statement “item x is A or B” would require that x can be only one of A and B. Furthermore, as used herein, “and/or” is intended to mean a grammatical conjunction used to indicate that one or more of the elements or conditions recited may be included or occur. For example, a device comprising a first element, a second element and/or a third element, is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or a device comprising a second element and a third element.
Moreover, as used herein, the phrases “comprises at least one of” and “comprising at least one of” in combination with a system or element is intended to mean that the system or element includes one or more of the elements listed after the phrase. For example, a device comprising at least one of: a first element; a second element; and a third element, is intended to be construed as any one of the following structural arrangements: a device comprising a first element; a device comprising a second element; a device comprising a third element; a device comprising a first element and a second element; a device comprising a first element and a third element; a device comprising a first element, a second element and a third element; or a device comprising a second element and a third element. A similar interpretation is intended when the phrase “used in at least one of:” is used herein.
Referring now to the figures,
Regenerator 20 comprises a plurality of piers or pillars 22, which are spaced apart to form regenerator regions 24. In an exemplary embodiment, each of pillars 22 comprises a plurality of bricks or blocks. Pillars 22 support corbels 40. In an exemplary embodiment, each of corbels 40 comprises a plurality of blocks. In an exemplary embodiment, each of corbels 40 comprises a plurality of blocks arranged in a plurality of tiers.
Corbels 40 are arranged on top of pillars 22 and support the oven section of coke oven battery 10. Specifically, corbels 40 support floor 28, heating walls 30, and coal 190 placed in ovens 34. Corbels 40 further allow fluid (e.g., gasses, air, etc.) to flow between flues 32 and regenerator 20. In an exemplary embodiment, corbels 40 allow gas to be injected into flues 32. For example, gas or fuel is injected into corbels 40 horizontally via hole 42 and flows vertically through holes 46 and into flues 32. Air flows upwardly through holes 48 and into flues 32 where it mixes with the fuel and combusts to heat heating walls 30, thus cooking the coal arranged in ovens 34 transforming it into coke. Exhaust gasses or fluids are created from such combustion within flues 32 and these hot exhaust gasses may flow down through holes 48 and into regenerator regions 24, thereby preheating the incoming gas and/or air. In an exemplary embodiment, air flows upwardly through holes 48 and exhaust gasses created from the combustions flow down through hole 50 (see
Floor 28 is arranged on and/or engaged with corbels 40. Floor 28 is operatively arranged to support the coal in ovens 34. Floor 28 may comprise a plurality of blocks. In an exemplary embodiment, the plurality of blocks are arranged in tiers. Heating walls 30 are arranged on corbels 40 and/or floor 28 and comprise flues 32 arranged therein, respectively. In an exemplary embodiment, heating walls 30 comprise bricks, blocks and/or modules. Flues 32 are in fluid communication with holes 46, holes 48, and/or holes 50 (see
In an exemplary embodiment, the transformation of coal into coke results in the production of coke oven gas (COG) within oven chambers 34. COG is recycled, processed, and used as fuel. As such, each oven 34 is equipped with duct or passageway 52 through which COG travels to be collected by COG collecting main 54. The COG is then refined and injected as fuel into holes 42. As such, coke oven battery 10 is in essence energy self-sustaining (although as a preliminary step coke oven battery 10 must be first ignited via an alternative fuel source). In an exemplary embodiment, the COG collected by COG collecting main 54 may be sent to a by-product plant for processing, refining, and/or treatment prior to being injected into gas gun 110 through holes 42. The COG may be refined to remove crude coal tar, remove crude benzol and light oils, scrub out ammonia, etc.
It is essential that the temperature TI of the air and/or exhaust gasses (i.e., the fluid) in stack 100 be greater than the temperature TO of the ambient air outside of stack 100. It is this temperature gradient AT that creates the natural draft that in turn facilitates the natural flow of fluid through system 12 (i.e., the fluid flow), and as such no fans or pumps are required to establish this fluid flow. In an exemplary embodiment, the temperature TI of the fluid in stack 100 is 200° F. to 500° F. higher than the temperature TO of the ambient air outside of stack 100 (i.e., a AT of 200° F. to 500° F.).
It is important thus to monitor the temperature of the fluid within stack 100 since, a reduction of AT will result in a decreased natural draft and a decreased potential fluid flow rate, and an increase in AT will result in an increased natural draft and increased potential fluid flow rate. In an exemplary embodiment, the temperature of the fluid is measured by temperature sensor 82. Temperature sensor 82 may be any sensor suitable for detecting the temperature of the fluid in conduit 184 and/or stack 100, for example, a negative temperature coefficient (NTC) thermistor, resistance temperature detector (RTD), thermocouple, or semiconductor-based integrated circuit (IC) sensor. In an exemplary embodiment, waste heat or exhaust tunnel 80 is fluidly arranged in conduit 184 between coke oven battery 10 and stack 100. Waste heat boxes 70 are each fluidly connected to waste heat tunnel 80, and as such, exhaust gasses and fluid from flues 32 travel to waste heat boxes 70 and empty into waste heat tunnel 80. In an exemplary embodiment, temperature sensor 82 is arranged on or in waste heat tunnel 80, stack 100, or conduit 184. In an exemplary embodiment, since fluid flowing from flues 32 through conduit 184 are the source of the heat in stack 100, their temperatures are likewise proportional to the temperature TI of stack 100.
Likewise, it is important to monitor the draft because it is proportional to the flow rate of the fluid. For example, increasing the draft may result in an increased flow rate of the fluid and a decreased AT, and decreasing the draft may result in a decreased flow rate of the fluid and an increased AT. In an exemplary embodiment, the draft is measured by sensor 86. In an exemplary embodiment, sensor 86 is a pressure transmitter (PT) that measures the pressure differential (i.e., draft) in waste heat tunnel 80 and/or conduit 184, as compared to atmospheric pressure. In an exemplary embodiment, controller 130 utilizes the pressure from sensor 86 to determine a pressure differential or draft, which is proportional to the flow rate of the fluid flowing through system 12 (e.g., through waste heat tunnel 80 and/or conduit 184). In an exemplary embodiment, sensor 86 is a draft sensor. Coke oven battery modulation system 12 further comprises damper or valve 90 arranged in conduit 184. Damper 90 comprises one or more valves or plates that regulate (i.e., stop or slow) the flow of fluid inside of conduit 184. Damper 90 may be a volume control damper used to control the flow of fluid within conduit 184. In an exemplary embodiment, damper 90 is arranged fluidly between waste heat tunnel 80 and stack 100. Damper 90 may be adjusted in order to increase or decrease the fluid flow rate (i.e., by adjusting the pressure differential or draft). For example, if the temperature TI is too low, damper 90 can be adjusted toward a closed or partially closed position to decrease the opening therein, which results in a decrease in the fluid flow rate which may increase fluid temperature TI. If the temperature TI is too high, damper 90 can be adjusted toward an open or partially open position to increase the opening therein, which results in an increase in the fluid flow rate which may decrease fluid temperature TI. In an exemplary embodiment, damper 90 is adjusted via actuator 92. In an exemplary embodiment, actuator 92 comprises a motor such as a direct current (DC) motor, synchronous or asynchronous motor, alternating current (AC) motor, stepper motor, or servomotor, an electric actuator, a hydraulic actuator, a pneumatic actuator, or the like for the purposes of adjusting the opening of damper 90.
In an exemplary embodiment, coke oven battery modulation system 12 further comprises oxygen sensor 84 operatively arranged to detect an amount of oxygen in the fluid flow (i.e., the air and/or exhaust gasses moving through conduit 184). The amount of oxygen in the fluid flow is indicative of the energy efficiency at which coke oven battery 10 is operating. Since oxygen is a key component in the combustion that occurs in flues 32 of heating walls 30, it is desired that as much oxygen as possible is consumed in the reaction (i.e., oxygen consumed correlates to reaction temperature). As such, a high amount of oxygen in the post-combustion fluid flow indicates poor combustion efficiency in coke oven battery 10, which may be due to, for example, the fluid flow rate being too high (i.e., the flow of air through coke oven battery 10 is moving too quickly and thus does not have enough time to react therein), or not enough fuel being supplied to coke oven battery 10 (i.e., a low fuel pressure in the fuel-gas mains). In an exemplary embodiment, it is desired that the fluid flow contain less than 12-18% oxygen.
In an exemplary embodiment, coke oven battery modulation system 12 further comprises waste heat or exhaust box 70 fluidly arranged in conduit 184 between coke oven battery 10 and stack 100. In an exemplary embodiment, waste heat box 70 is fluidly arranged in conduit 184 between coke oven battery 10 and waste heat tunnel 80. In an exemplary embodiment, there is one or more waste heat boxes 70 for each wall 30 in coke oven battery 10 (e.g., each flue 32 is fluidly connected to a waste heat box 70). Waste heat box 70 may comprise one or more valves, for example, valve 72 and valve 74. In an exemplary embodiment, valve 72 is a quadrant valve. In an exemplary embodiment, valve 74 is a mushroom or poppet valve. Valves 72 and 74 are operatively arranged to control the draft and affect flow rate of the fluid flow from each flue or zone of flues 32 to conduit 184. In an exemplary embodiment, valve 72, 74 in waste heat box 70 is operatively arranged to control (i.e., start and stop) the fluid flow from each individual zone of a heating wall 30.
As shown in
In an exemplary embodiment, coke oven battery modulation system 12 may further comprise valve 62 operatively arranged to modulate the COG supplied to gas gun 110. In an exemplary embodiment, valve 62 is controlled by actuator 64. In an exemplary embodiment, coke oven battery modulation system 12 further comprises fuel pressure sensor 66. Fuel pressure sensor 66 is operatively arranged to detect fuel pressure being supplied to gas gun 110 and communicate with actuator 64 to adjust valve 62 such that the correct fuel pressure and thus fuel flow is being supplied to gas gun 110.
In an exemplary embodiment, coke oven battery modulation system 12 may further comprise temperature sensor 88 operatively arranged to detect a temperature of heating walls 30. In an exemplary embodiment, temperature sensor 88 comprises a pyrometer. In an exemplary embodiment, coke oven battery modulation system 12 may further comprise one or more flue pressure sensors FP operatively arranged to detect a pressure in flue 32. The differential of pressure between flue 32 and oven 34 is important to regulate since a high pressure in oven 34 and a low pressure in flue 32 may drive COG through heating walls 30 and into flue 32, which could lead to an increase in opacity. It should be appreciated that, in exemplary embodiments, if managed and balanced effectively this pressure differential between flue 32 and oven 34 may also be used to drive methane through the slightly permeable heating walls 30 to produce wall carbon which could, over time, lead to a decrease is average opacity.
Coke oven battery modulation system 12 further comprises opacity sensor or monitor 102 operatively arranged to measure the opacity within stack 100. In an exemplary embodiment, sensor 102 is a continuous opacity monitoring system (COMS). Opacity is the fraction of light lost in crossing through the inside of stack 100 due to lack of transparency. Variable fluid flow and composition in stack 100 causes the opacity therein to fluctuate. For various reasons, over time the opacity of the stack tends to increase when the flow rate of the fluid flow decreases. The opacity of the stack decreases over time when the flow rate of the fluid flow increases. Thus, the opacity can be modulated by increasing and decreasing the flow rate of the fluid flow, for example, via damper 90.
Regulations (e.g., the Clean Air Act) set certain requirements on emissions in order to reduce and control air pollution. One type of requirement is that the opacity of stack 100 be less than a first predetermined threshold (e.g., 20%), or a fine may be issued to the operator of that coke oven battery. The opacity requirement may be measured as an average over a period of time. For example, if the 24-hour average opacity in stack 100 is greater than or equal to 20%, a first fine is issued. Additionally, if the average (or an instantaneous or a 6-minute rolling) opacity for a period of time is greater than a second predetermined threshold (e.g., 60%), which is greater than the first predetermined threshold, an additional fine may be issued. For example, if a 6-minute rolling average opacity in stack 100 is greater than or equal to 60%, both a first fine for exceeding the first 20% threshold and a second fine for exceeding the second 60% threshold may be issued. The second fine may be exponentially higher than the first fine.
Controller 130 may be a hardware device that receives data from one or more sensors and modulates the coke oven battery system using coke oven battery modulation program 132. In an exemplary embodiment, controller 130 may include a computer. In an exemplary embodiment, controller 130 may include internal and external hardware components, as depicted and described in further detail with respect to
Coke oven battery modulation program 132 can receive input from one or more sensors, for example, opacity sensor 102, temperature sensors 82 and 88, oxygen sensor 84, and sensor 86, determine one or more necessary actions to modulate the coke oven battery system, and send signals to one or more actuators to carry out the one or more necessary actions, based on the various methods disclosed herein. Coke oven battery modulation program 132 can generally include any software capable of modulating a coke oven battery system to maintain a tolerable opacity without adversely impacting proper fluid flow rate (i.e., draft with respect to stack 100) or proper heating in coke oven battery 10. In an exemplary embodiment, coke oven battery modulation system 14 further comprises a database (not shown). Coke oven battery modulation program 132 is capable of storing historical data in the database such that, over a period of time (e.g., 10 years), coke oven battery modulation program 132 can view the long-term effects of its decision making in an effort to learn, for example through the use of artificial intelligence (AI). For example, coke oven battery modulation program 132 may track the long-term average trend in waste oxygen (i.e., in the fluid flow or exhaust), which may be indicative of inefficient combustion in coke oven battery 10 and/or damage to components of coke oven battery 10 (i.e., cracks in heating walls 30 leading to leakage of battery gasses into flues 32).
In an exemplary embodiment, controller 130 receives data from opacity sensor 102 and based thereon, sends a signal to actuator 92 to open or close damper 90. In an exemplary embodiment, coke oven battery modulation system 14 further comprises draft controller 140 which operates actuator 92 to open and close damper 90. In an exemplary embodiment, damper 90 comprises set point 144 which is the predetermined value of the draft (e.g., a pressure differential of 20 mm of water column). As previously described, the value of the draft is proportional to the potential flow rate of the fluid flow. The predetermined value of the draft is the desired draft as induced by the position of damper 90 (e.g., 20° open). In an exemplary embodiment, set point 144 comprises bias 142 which is the allowable modulation of set point 144. For example, if set point 144 is 20 mm of water column and bias 142 is 10%, then the allowable system modulation of the draft is 2 mm of water column (+1 mm of water column). In an exemplary embodiment, draft controller 140 comprises a single loop controller or PLC. For example, if the rolling average baseline opacity of stack 100 is greater than a second predetermined threshold (e.g., 15%), coke oven battery modulation program 132 increases the opening of damper 90 to increase the fluid flow rate. While this action will decrease the opacity, it may also result in a less efficient combustion in coke oven battery 10. A less efficient combustion in coke oven battery 10 may eventually lead to failure of various components thereof, for example, the heating walls 30, which may allow COG to leak into flues 32 and into the fluid flow of conduit 184, therefore leading to an increase in opacity. Coke oven battery modulation program 132 interprets all of this data, and may factor in long term effects of its modulation decision making, in order to maintain the longevity of coke oven battery 10 and comply with opacity regulations simultaneously. In an exemplary embodiment, coke oven battery modulation system 14 further comprises finger bars 122. Finger bars 122 are operatively arranged to control how much air gets pulled into air box 120. Combustion air flows around the obstructing finger bars 122 and into air box(es) 120, and into coke oven battery 10 via hole 48.
In an exemplary embodiment, coke oven battery modulation program 132 receives an input setting a base level or range for rolling average baseline stack opacity (e.g., 10-15%), the period defining the rolling average baseline opacity (e.g., 6 hours), and a bias applied to the draft set point (e.g., 5-15%). In an exemplary embodiment, the draft set point bias is set to 10%. Coke oven battery modulation program 132 receives data and determines: 1) the percent of time the 6-hour rolling average of the baseline opacity was within the base range, 2) the percent of time the 6-hour rolling average was above the base range, 3) the percentage of time the 6-hour rolling average was below the base range, and 4) the current bias applied to the draft set point based on its present rolling average at any given time. Coke oven battery modulation program 132 utilizes this and other data to minimize opacity without adversely affecting required waste heat or fluid flow temperature (e.g., preferably 350-600° F.) and without exceeding a desired combustion efficiency limit (i.e., control excess air to avoid wasting too much heat and cooling coke oven battery 10 or the fluid flow).
In an exemplary embodiment, coke oven battery modulation program 132 receives an input setting a base level or range for rolling average baseline stack opacity (e.g., 10-15%), the period of rolling average baseline opacity (e.g., 2-10 hours), a bias to be applied to the draft set point (e.g., 5-15%), and a fuel bias (e.g., 0-10%). In an exemplary embodiment, draft set point bias is set to 10%. Coke oven battery modulation program 132 receives data and determines: 1) the percent of time the rolling average was within the base range, 2) the percent of time the rolling average was above the base range, 3) the percent of time the rolling average was below the base range, 4) the current bias applied to the draft set point based on that rolling average, and 5) the current bias applied to the fuel pressure set-point based on that rolling average. Coke oven battery modulation program 132 utilizes this and other data to minimize opacity without adversely affecting required waste heat temperature (e.g., preferably 350-600° F.) and without exceeding a desired combustion efficiency limit (i.e., control excess air to avoid wasting too much heat and cooling coke oven battery 10 down), and reduce fuel to coke oven battery 10 when combustion is rich without cutting so much as to reduce grand average temperatures of coke oven battery 10.
In an exemplary embodiment, coke oven battery modulation program 132 receives an input setting a base range for rolling average baseline stack opacity (e.g., 10-15%), a period of the rolling average baseline opacity (e.g., 2-10 hours), a bias applied to the draft set point (e.g., 5-15%), a fuel bias (e.g., 0-10%), and an overall maximum bias allowed depending on temperatures and fluid flow oxygen levels. In an exemplary embodiment, draft set point bias is set to 10%. Coke oven battery modulation program 132 receives data and determines: 1) the percent of time the rolling average was within the base range, 2) the percent of time the rolling average was above the base range, 3) the percent of time the rolling average below the base range, 4) the current bias applied to the draft set point based on that rolling average, 5) the current bias applied to the fuel pressure set-point based on that rolling average, 6) the fluid flow temperature, 7) the fluid flow oxygen level, 8) the desired grand average battery temperature, 9) the most recent actual measured grand average battery temperatures, 10) system bias adjustment based on these three temperatures and the oxygen level, and 11) the overall biases applied. Coke oven battery modulation program 132 utilizes this and other data to minimize opacity without adversely affecting required fluid flow temperature (e.g., preferably 350-600° F.) and without exceeding a desired combustion efficiency limit (i.e., control excess air to avoid wasting too much heat and cooling coke oven battery 10 down), and reduce fuel to coke oven battery 10 when combustion is rich without cutting so much as to reduce grand average temperatures of coke oven battery 10.
It should be appreciated that coke oven battery modulation system 12, 14, 16, 18 attempts to modulate the coke oven battery system to maintain desirable levels, namely, a fluid flow temperature ranging from 300-600° F., a fluid flow oxygen level of 12-18%, a fluid flow pressure of 18-28 mm of water column and preferably 22 mm of water column, a draft set point bias range of approximately 10%, a fuel pressure bias range of approximately 5%, a AT of at least 300° F., and a rolling-average baseline opacity of 5-15% and preferably a 24-hour rolling average opacity of less than 18%.
In step 202, coke oven battery modulation program 132 receives an input. As previously described, the input may comprise data from one or more sensors, for example, fluid flow temperature sensor 82, fluid flow oxygen sensor 84, fluid flow pressure or flow rate sensor 86, heating wall 30 or coke oven battery 10 temperature sensor 88, opacity sensor 102, fuel pressure sensor 160, or an operator via input 170. In an exemplary embodiment, data received in step 202 is a rolling average value over a period of time (e.g., temperature, oxygen level, opacity, fuel pressure, etc.). In an exemplary embodiment, data received in step 202 is in real time, and coke oven battery modulation program 132 calculates the rolling average over a period of time, for example, six hours.
In step 204, coke oven battery modulation program 132 calculates a baseline opacity. In an exemplary embodiment, the baseline opacity is calculated by filtering out all the opacity data greater than a threshold (e.g., 40%). This removes any “opacity spikes” from the rolling average opacity in an effort to modulate coke oven battery 10 in a more gradual fashion (i.e., by specifically controlling the battery baseline heating combustion efficiency and not by controlling either total instantaneous opacity or by controlling total rolling average opacity). Specifically, opacity sensor 102 may send opacity data to coke oven battery modulation program 132 every period of time (e.g., 2 minutes). Some of that opacity data may include a data point that is either outside of the norm, or an outlier data point (e.g., 60%). Since modulating a coke oven system based on such spikes or outliers may be ineffective or trigger unnecessary or unwanted modulation, coke oven battery modulation program 132 may remove such outliers prior to performing subsequent modulation decision making. Periods of high opacity above the baseline threshold are likely to be caused by events or operational conditions that are not amenable to continuous long-term control by fuel flow modulation and/or draft modulation. Modulating combustion under these circumstances, in a manner proportional to the spiked opacity, is not likely to have any effect, positive or negative, on either the spike opacity or its causes. It is instead likely to cause negative side effects on other parameters including, but not limited to, fluid flow temperature, fluid flow oxygen levels, fluid flow pressure, available draft, and battery temperatures.
In step 206, coke oven battery modulation program 132 determines whether the opacity (e.g., baseline opacity) in stack 100 is less than a first predetermined threshold. In an exemplary embodiment, the first predetermined threshold is 10%.
If, in step 206, coke oven battery modulation program 132 determines that the opacity in stack 100 is less than the first predetermined threshold, then in step 208 coke oven battery modulation program 132 increases the fuel pressure or supply and/or decreases the fluid flow rate. In an exemplary embodiment, coke oven battery modulation program 132 sends one or more signals to actuator 152 to bias valve 150 toward a more open or partially opened position thus increasing the opening in conduit 180. As previously described, increasing fuel pressure, under such circumstances, increases the combustion efficiency and heat within coke oven battery 10. In an exemplary embodiment, coke oven battery modulation program 132 sends one or more signals to actuator 92 to bias damper 90 toward a more closed or partially closed position thus decreasing the opening in conduit 184. As previously described, decreasing fluid flow rate, under such circumstances, increases the combustion efficiency and heat within coke oven battery 10. The method then proceeds back to step 202. It should be appreciated that, in exemplary embodiments, coke oven battery modulation program 132 further ensures that draft set point bias does not exceed a predetermined range (e.g., +5%) and that fuel set point bias does not exceed a predetermined range (e.g., +2.5%). %) as demonstrated in
If, in step 206, coke oven battery modulation program 132 determines that the opacity in stack 100 is not less than the first predetermined threshold, then in step 210 coke oven battery modulation program 132 determines if the opacity in stack 100 is greater than (or equal to) a second predetermined threshold. In an exemplary embodiment, the second predetermined threshold is 15%.
If, in step 210, coke oven battery modulation program 132 determines that the opacity in stack 100 is not greater than the second predetermined threshold, then the method continues back to step 202 and essentially coke oven battery modulation program 132 determines that the opacity in stack 100 is within an acceptable operational level (vs. regulatory level).
If, in step 210, coke oven battery modulation program 132 determines that the opacity in stack 100 is greater than the second predetermined threshold, then in step 212 coke oven battery modulation program 132 determines if the oxygen level of the waste exhaust gas or fluid flow is less than a third predetermined threshold. In an exemplary embodiment, the third predetermined threshold is 12-18%. In an exemplary embodiment, in step 212, coke oven battery modulation program 132 determines if the average oxygen level of the waste exhaust gas or fluid flow is less than a third predetermined threshold.
If, in step 212, coke oven battery modulation program 132 determines that the oxygen level of the fluid flow is less than the third predetermined threshold, then in step 214 coke oven battery modulation program 132 decreases the fuel pressure or supply. As previously described, decreasing the fuel supply may reduce opacity levels in stack 100. In an exemplary embodiment, coke oven battery modulation program 132 sends one or more signals to actuator 152 to bias valve 150 toward a more closed or partially closed position thus decreasing the opening in conduit 180. It should be appreciated that, in exemplary embodiments, coke oven battery modulation program 132 further ensures that fuel set point bias does not exceed a predetermined range (e.g., +2.5%) as demonstrated in
If, in step 212, coke oven battery modulation program 132 determines that the oxygen level is not less than the third predetermined threshold, then the method continues back to step 202.
If, in step 210, coke oven battery modulation program 132 determines that the opacity in stack 100 is greater than the second predetermined threshold, then in step 216 coke oven battery modulation program 132 determines if the temperature of the fluid flow is greater than a fourth predetermined threshold. In an exemplary embodiment, the fourth predetermined threshold is 350° F. In an exemplary embodiment, in step 216, coke oven battery modulation program 132 determines if the average temperature of the fluid flow is greater than a fourth predetermined threshold.
If, in step 216, coke oven battery modulation program 132 determines that the temperature of the fluid flow is not greater than the fourth predetermined threshold, then the method proceeds back to step 202.
If, in step 216, coke oven battery modulation program 132 determines that the temperature of the fluid flow is greater than the fourth predetermined threshold, then in step 218 coke oven battery modulation program 132 increases the fluid flow rate. As previously discussed, increasing the fluid flow rate may reduce the opacity within stack 100. It should be appreciated that, in exemplary embodiments, coke oven battery modulation program 132 further ensures that draft set point bias does not exceed a predetermined range (e.g., +5%) as demonstrated in
In an exemplary embodiment, coke oven battery modulation program 132 modulates the coke oven battery system when opacity is at low points. That is, coke oven battery modulation program 132 biases damper 90 toward a closed or partially closed position when opacity is below the first threshold (or, for example, biases damper 90 toward an open or partially open position when opacity is above the second threshold) in order to maintain better efficiency within coke oven battery 10. While this may result in a temporary increased opacity average, the long-term effect of this method is higher energy and combustion efficiency and an increased lifespan of the coke oven battery and the components therein and in a preservation of coke oven wall integrity which improves the probability of achieving opacity regulatory limits in the future.
In step 252, coke oven battery modulation program 132 receives an input. For example, coke oven battery modulation program 132 may receive opacity data (e.g., rolling average opacity data) from opacity sensor 102.
In step 254, coke oven battery modulation program 132 determines a set point bias for the draft. In an exemplary embodiment, coke oven battery modulation program 132 uses chart 258 to determine the set point bias for the draft from the opacity data received in step 252. As shown, chart 258 may comprise a graph or step function correlating opacity data to preferred draft set point bias. In an exemplary embodiment, chart 258 comprises a predetermined step function.
In step 256, coke oven battery modulation program 132 communicates with actuator 92 to adjust damper 90. In an exemplary embodiment, in step 256, coke oven battery modulation program 132 communicates the determined set point bias to draft controller 140. Damper 90 is then adjusted to the proper setting to achieve the newly biased set point.
In step 260, coke oven battery modulation program 132 determines a set point bias for fuel. In an exemplary embodiment, coke oven battery modulation program 132 uses chart 264 to determine the set point bias for fuel from the opacity data received in step 252. As shown, chart 264 may comprise a graph or step function correlating opacity data to preferred fuel set point bias. In an exemplary embodiment, chart 264 comprises a predetermined step function.
In step 262, coke oven battery modulation program 132 communicates with actuator 152 to adjust valve 150. In an exemplary embodiment, in step 262, coke oven battery modulation program 132 communicates the determined set point bias to fuel pressure controller 154. Valve 150 is then adjusted to the proper setting to achieve the newly biased set point. It should be appreciated that steps 254-256, and steps 260-262 may occur simultaneously or sequentially with respect to each other.
Computing device 300 includes communications fabric 302, which provides for communications between one or more processing units 304, memory 306, persistent storage 308, communications unit 310, and one or more input/output (I/O) interfaces 312. Communications fabric 302 can be implemented with any architecture designed for passing data and/or control information between processors (such as microprocessors, communications and network processors, etc.), system memory, peripheral devices, and any other hardware components within a system. For example, communications fabric 302 can be implemented with one or more buses.
Memory 306 and persistent storage 308 are computer readable storage media. In this embodiment, memory 306 includes random access memory (RAM) 316 and cache memory 318. In general, memory 306 can include any suitable volatile or non-volatile computer readable storage media. Software is stored in persistent storage 308 for execution and/or access by one or more of the respective processors 304 via one or more memories of memory 306.
Persistent storage 308 may include, for example, a plurality of magnetic hard disk drives. Alternatively, or in addition to magnetic hard disk drives, persistent storage 308 can include one or more solid state hard drives, semiconductor storage devices, read-only memories (ROM), erasable programmable read-only memories (EPROM), flash memories, or any other computer readable storage media that is capable of storing program instructions or digital information.
The media used by persistent storage 308 can also be removable. For example, a removable hard drive can be used for persistent storage 308. Other examples include optical and magnetic disks, thumb drives, and smart cards that are inserted into a drive for transfer onto another computer readable storage medium that is also part of persistent storage 308.
Communications unit 310 provides for communications with other computer systems or devices via a network. In this exemplary embodiment, communications unit 310 includes network adapters or interfaces such as a TCP/IP adapter cards, wireless Wi-Fi interface cards, or 3G, 4G, or 5G wireless interface cards or other wired or wireless communications links. The network can comprise, for example, copper wires, optical fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. Software and data used to practice embodiments of the present disclosure can be downloaded to computing device 300 through communications unit 310 (i.e., via the Internet, a local area network, or other wide area network). From communications unit 310, the software and data can be loaded onto persistent storage 308.
One or more I/O interfaces 312 allow for input and output of data with other devices that may be connected to computing device 300. For example, I/O interface 312 can provide a connection to one or more external devices 320 such as a keyboard, computer mouse, touch screen, virtual keyboard, touch pad, pointing device, or other human interface devices. External devices 320 can also include portable computer readable storage media such as, for example, thumb drives, portable optical or magnetic disks, and memory cards. I/O interface 312 also connects to display 322.
Display 322 provides a mechanism to display data to a user and can be, for example, a computer monitor. Display 322 can also be an incorporated display and may function as a touch screen, such as a built-in display of a tablet computer.
The present disclosure may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present disclosure.
The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire.
Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device.
Computer readable program instructions for carrying out operations of the present disclosure may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present disclosure.
Aspects of the present disclosure are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the disclosure. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions.
These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks.
The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks.
The flowchart and block diagrams in the figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions.
It will be appreciated that various aspects of the disclosure above and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.
This application claims the benefit under 35 U.S.C. § 119 (e) of U.S. Provisional Application No. 63/585,051, filed Sep. 25, 2023, which application is incorporated herein by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63585051 | Sep 2023 | US |
