Patent Application
20240384870
The present invention relates to the purification of fluids. In particular, the present invention relates to a fluid purification system and a method for fluid purification.
Process gases that contain combustible constituents such as combustible gases, vapors, solvents, other volatile organic components, combustible pollutants and/or mixtures thereof may be disposed of thermally via various methods. For example, combustion in directly fired combustion chambers is possible. In doing so, a burner heats up the combustion chamber and the process gases are introduced into the combustion chamber via appropriate injection devices (e.g. lances), used as combustion air or mixed with the combustion air. At the appropriate temperature and dwell time, the process gases and/or their combustible constituents oxidize completely in the combustion chamber. Subsequently, the hot gases are cooled and, if no further treatment is required to remove pollutants, released into the environment via a stack.
Direct oxidation in a combustion chamber is advantageous if low exhaust air flows with a high load or pollutants with a high corrosion potential (e.g. halogenated compounds) are to be disposed of. If the supplied gases have a correspondingly high calorific value, the burner may be reduced to minimum consumption. Another advantage of direct oxidation in a combustion chamber is that gases that are present as a potentially ignitable mixture or have a quasi-fuel-like composition may also be disposed of. However, if the calorific value of the gases to be disposed of decreases, additional primary fuel (e.g. natural gas) must be burned or added and/or other heating energy must be supplied in order to maintain a temperature required for direct oxidation in the combustion chamber. However, if the heat generated cannot be used, such exhaust air purification is neither economically nor ecologically sensible over a longer period of time.
Low-loaded process gases may be disposed of by means of regenerative thermal oxidation (RTO) with significantly lower primary energy requirements. However, if the concentrations of flammable compounds increase here, the safety of the system must be ensured by appropriate dilution with air or purified gas. A disadvantage of systems based on the RTO principle is the necessary resistance to corrosion (e.g. with halogenated compounds in the exhaust gas), which may often only be achieved by selecting specific materials (e.g. high-quality, corrosion-resistant stainless steels) and the associated higher costs for the systems.
Neither direct-fired combustion chambers nor systems based on the RTO principle are therefore suitable for all conceivable operating conditions and/or tasks.
Against this background, it is a task of the present invention to provide an improved possibility for purifying fluids such as exhaust gas or exhaust air.
The problem according to the invention is solved by a fluid purification system and a method for fluid purification according to the independent claims. Further aspects and further developments of the invention are described in the dependent claims, the following description and in the figures.
According to a first aspect, the invention relates to a fluid purification system. The fluid purification system comprises a regenerative thermal oxidation device (RTO device) with a first combustion chamber and at least one regenerator. The RTO device is configured to purify a first fluid flow by means of RTO. Furthermore, the fluid purification system comprises a second combustion chamber separate from the RTO device, which is configured to purify a second fluid flow different from the first fluid flow by means of thermal oxidation. The fluid purification system further comprises a heat transport device configured to transport process heat from the RTO device to the second combustion chamber to set a temperature in the second combustion chamber.
According to a second aspect, the invention relates to a method for fluid purification. The method comprises RTO of a first fluid flow in an RTO device with a first combustion chamber and at least one regenerator. Furthermore, the method comprises thermal oxidation of a second fluid flow in a second combustion chamber separate from the RTO device. The second fluid flow is different from the first fluid flow. In addition, the method comprises setting a temperature in the second combustion chamber by means of process heat transported from the RTO device to the second combustion chamber.
The system according to the invention as well as the method according to the invention allow the a synergistic use of direct thermal oxidation and RTO to enable safe and economical operation. The additional combustion space provided by the second combustion chamber may be warmed up with the process heat of the RTO device in order to safely oxidize not only the first fluid flow but also, for example, a second fluid flow which is highly calorific and/or loaded with corrosive substances in the second combustion chamber. Accordingly, highly corrosion-resistant materials may be dispensed with for the RTO device. The second fluid flow may be, for example, exhaust air, exhaust gas and/or liquid flows, whereby it is particularly advantageous in the sense of the invention if constituents of this second fluid flow would have a negative impact on the treatment in a conventional RTO device. Examples include corrosive constituents, high-energy constituents that exceed the capacity of the RTO device, constituents that damage the heat exchanger ceramic and constituents that may lead to contamination in the RTO device. By combining thermal oxidation and RTO, separate individual solutions may be dispensed with and thus, for example, the safety features of the RTO device may also be used for the second combustion chamber. Accordingly, the costs for the system according to the invention and/or performing the method according to the invention may be reduced compared to known approaches. In particular, the second combustion chamber allows a flexible and safe thermal treatment of the second fluid flow, since the second combustion chamber may be warmed up by means of the process heat of the RTO device without lengthy and/or extensive preparations (e.g. starting a burner to heat up).
Some examples of devices and/or methods will be described in the following by way of example only and with reference to the accompanying figures, in which:
Some examples are now described in more detail with reference to the enclosed figures. However, other possible examples are not limited to the features of these embodiments described in detail. These may include modifications of the features as well as equivalents and alternatives to the features. Furthermore, the terminology used herein to describe certain examples should not be restrictive of further possible examples.
Throughout the description of the figures, same or similar reference numerals refer to same or similar elements and/or features, which may, in each case, be identical or implemented in a modified form while providing the same or a similar function. The thickness of lines, layers and/or areas in the figures may also be exaggerated for clarification.
When two elements A and B are combined using an ‘or’, this is to be understood as disclosing all possible combinations, i.e., only A, only B as well as A and B, unless expressly defined otherwise in the individual case. As an alternative wording for the same combinations, “at least one of A and B” or “A and/or B” may be used. This applies equivalently to combinations of more than two elements.
If a singular form, such as “a,” “an” and “the” is used and the use of only a single element is not defined as mandatory either explicitly or implicitly, further examples may also use several elements to implement the same function. If a function is described below as implemented using multiple elements, further examples may implement the same function using a single element or a single processing entity. It is further understood that the terms “include”, “including”, “comprise” and/or “comprising”, when used, describe the presence of the specified features, integers, steps, operations, processes, elements, components and/or a group thereof, but do not exclude the presence or addition of one or more other features, integers, steps, operations, processes, elements, components and/or a group thereof.
The functionality of the fluid purification system 100 does not depend on the specific design of the RTO device 110. The RTO device 110 may therefore be embodied in a variety of ways. For example, the RTO device 110 may be a 1-tower RTO device, a multi-tower RTO device (e.g., a 2-, 3-, or 5-tower RTO device), an RTO device with a rotating regenerator, or an RTO device with a fixed bed and a rotating system for introducing the first fluid flow 101 and discharging the flue gas obtained during thermal oxidation. All of the aforementioned embodiments for the RTO device 110 have in common that they comprise a first combustion chamber 111 and at least one regenerator 112. Optionally, the RTO device may comprise further elements. The fluid flow 101 is thereby routed through the at least one regenerator 112 by the RTO device 110 to warm up the fluid and subsequently thermally oxidize it in the combustion chamber 112. Substantially, the first fluid flow 101 oxidizes to water and carbon dioxide. Subsequently, the flue gas obtained from the thermal oxidation is routed via the at least one regenerator 112 to an output of the RTO device 110 to store the heat of the flue gas. The term “flue gas” generally refers to gas after thermal post-combustion and/or oxidation.
The regenerator 112 is embodied as a discontinuously operating heat exchanger which cyclically temporarily stores the energy content of a first mass flow (in this case the hot flue gas obtained during RTO) and transfers it to a second mass flow (in this case the first fluid flow 101) of lower temperature for heating up. Both mass flows flow through the same heat storage elements of the regenerator 112 in chronological order. For example, the regenerator may comprise one or more heat transfer beds filled with a ceramic material. The ceramic material may be, for example, alumina porcelain, mullite, fireclay, cordierite, zircon or mixtures thereof. However, also other materials may be used. The ceramic material may be structured or irregularly packed in the respective heat transfer bed to form regular or irregular patterns.
In the first combustion chamber 111, a temperature (e.g. greater than 800° C.) prevails at which the pollutants and/or combustible constituents contained in the first fluid flow 101 thermally oxidize. The RTO device 110 comprises at least one burner (not shown in
The purified flue gas is emitted by the RTO device 110 in the form of a first flue gas flow 104. The first flue gas flow 104 may either be supplied to a secondary purification stage to remove one or more pollutants still contained and/or remaining in the flue gas flow 104 from the flue gas flow 104, or discharged into the environment (e.g., via a stack). For example, the first flue gas flow 104 may be supplied to a wet scrubber (e.g., with packed bed) to transfer acidic components contained in the first flue gas flow 104 into the liquid phase, thereby removing them from the first flue gas flow 104 and subsequently disposing of the acidic components via a wastewater treatment. It is to be noted that other forms of post-treatment of the first flue gas flow 104 are also possible. If no further purification stages for the removal of one or more further pollutants from the flue gas flow 104 follow, the first flue gas flow 104 may also be understood as a first purified gas flow and discharged directly into the environment.
Furthermore, the fluid purification system 100 comprises a second combustion chamber 120 separate from the RTO device 110. In other words: The second combustion chamber 120 is a reaction space separate from the RTO device 120. The second combustion chamber 120 is configured to receive a second fluid flow 102 different from the first fluid flow 101 and to purify it by means of (direct) thermal oxidation. The second fluid flow 102 is a second fluid loaded with one or more pollutants from at least one pollutant-emitting process and/or at least one pollutant-emitting device. The first fluid flow 101 and the second fluid flow 102 may be emitted from the same process and/or the same device or from different processes and/or devices. The pollutants contained in the second fluid flow 102 may be, for example, the pollutants mentioned above in connection with the first fluid flow 101. Alternatively, the second fluid flow 102 may also contain one or more other pollutants than the first fluid flow 101 (e.g. halogenated compounds). The pollutants contained in the second fluid flow 102 may thus at least partly be combustible substances, such that the second fluid flow 102 may also be understood as a second fluid loaded with one or more combustible substances from at least one process emitting combustible substances and/or at least one device emitting combustible substances. The second fluid flow 102 may generally comprise one or more liquid constituents and/or substances, one or more vaporous constituents and/or substances, one or more gaseous constituents and/or substances and/or mixtures thereof. In particular, the second fluid flow 102 may comprise exclusively gaseous constituents and/or substances and may be, for example, an exhaust gas flow or an exhaust air flow that contains a higher proportion of oxygen than an exhaust gas flow.
The second fluid flow 102 differs from the first fluid flow 101 in at least one of the following aspects and/or features:
The thermal oxidation converts the pollutant(s) and/or combustible constituents contained in the second fluid flow 102 into largely harmless substances, and the second fluid flow 102 is thus purified by the second combustion chamber 120. Substantially, the second fluid flow 102 oxidizes to water and carbon dioxide. The flue gas obtained during thermal oxidation of the second fluid flow 102 is routed to an output of the second combustion chamber 120.
In the second combustion chamber 120, a temperature (e.g. greater than 800° C.) prevails at which the pollutants and/or combustible constituents contained in the second fluid flow 102 thermally oxidize. Depending on the energy content of the second fluid flow 102, thermal oxidation may take place with or without additional combustion of an additional fuel.
The purified flue gas is emitted by the second combustion chamber 120 in the form of a second flue gas flow 105. The second flue gas flow 105 may either be supplied to a secondary fluid purification to remove one or more pollutants still contained and/or remaining in the second flue gas flow 105 from the second flue gas flow 105, or discharged into the environment (e.g., via a stack). For example, the second flue gas flow 105 may be supplied to a wet scrubber (e.g. with packed bed) to transfer acidic components contained in the second flue gas flow 105 into the liquid phase, thereby removing them from the second flue gas stream 105 and subsequently disposing of the acidic components via a wastewater treatment. It is to be noted that other forms of post-treatment of the second flue gas flow 105 are also possible. If no further purification stages for the removal of one or more further pollutants from the second flue gas flow 105 follow, the second flue gas flow 105 may also be understood as a second purified gas flow and discharged directly into the environment.
The fluid purification system 100 further comprises a heat transport device 130 coupled to both the RTO device 110 and the second combustion chamber 120. The heat transport device 130 is configured to transport process heat 103 from the RTO device 110 to the second combustion chamber 120 to set a temperature in the second combustion chamber 120. The term “process heat” therein refers to the waste heat released in the RTO device 110 during the RTO of the first fluid flow 101. The heat transport device 130 comprises one or more lines for transporting the process heat 103, and optionally one or more controllable means for setting the process heat 103 routed per time unit from the RTO device 110 to the second combustion chamber 120. Similarly, the heat transport device 130 may comprise one or more sensors for measuring the process heat 103 routed per time unit from the RTO device 110 to the second combustion chamber 120 and, if necessary, other parameters of the process heat 103.
The fluid purification system 100 enables synergistic utilization of thermal oxidation and RTO to enable safe and economical disposal of the two fluid flows 101 and 102. The additional combustion space provided by the second combustion chamber 120 is warmed up with the process heat 103 of the RTO device 110 in order to be able to dispose of the second fluid flow 102 separately in addition to the first fluid flow 101. By combining thermal oxidation and RTO, separate individual solutions may be dispensed with and thus, for example, the safety features of the RTO device 110 may also be used for the second combustion chamber 120. Accordingly, the costs for the fluid purification system 100 may be reduced compared to known approaches. In particular, the second combustion chamber 120 allows a flexible and safe thermal treatment of the second fluid flow, since the second combustion chamber 120 may be warmed up by means of the process heat 103 of the RTO device 110 without lengthy and/or extensive preparations (e.g. starting a burner in the second combustion chamber 120 to heat it up) and thus be made ready for operation.
For example, the second fluid flow 102 may have a higher calorific value than the first fluid flow 101. For safety reasons, RTO is only suitable to a limited extent for the thermal oxidation of highly calorific mass flows, in contrast to thermal oxidation in a combustion chamber. The proportion of combustible substances and/or pollutants in the second fluid flow 202 may, for example, be more than 25% of the Lower Explosive Limit (LEL), while the proportion of combustible substances and/or pollutants in the first fluid flow 201 is less than 25% of the LEL. The additional second combustion chamber 120 of the fluid purification system 100 thus enables the thermal oxidation of fluid flows as required with different energy contents in parallel. The RTO device 110 enables efficient disposal of the first fluid flow 101 having a lower calorific value, while the second combustion chamber 120 enables safe disposal of the second fluid flow 102 having a higher calorific value.
Similarly, a concentration of pollutants in the second fluid flow 102 may be higher than in the first fluid flow 101. Since direct oxidation in a combustion chamber is more suitable for the thermal oxidation of highly charged gas flows than RTO, the fluid purification system 100 enables the fluid flows 101 and 102 to be disposed of as required for the aforementioned composition.
A volume flow of the second fluid flow 102 may also be less than a volume flow of the first fluid flow 101. Since RTO is better suited for thermal oxidation of high volume flows than direct oxidation in a combustion chamber, the fluid purification system 100 enables the fluid flows 101 and 102 to be disposed of as required for the aforementioned volume flows.
In some embodiments, the second fluid flow 102 may contain at least one corrosive substance (e.g., halogenated compounds), wherein the first fluid flow 101 does not contain any corrosive substances. Accordingly, highly corrosion-resistant materials such as corrosion-resistant stainless steels may be dispensed with for the RTO device 110. In addition to a disposal as required of the fluid flows 101 and 102, the costs for the RTO device 110 may be kept low by the additional second combustion chamber 120 for the disposal of the corrosive second fluid flow 102.
In some further embodiments, the second fluid flow 102 may contain at least one substance and/or constituent (e.g., organosilicon compounds, metals, etc.) that tends or leads to precipitate formation, wherein the first fluid flow 101 contains no or at least few such substances. Accordingly, purification measures and/or short maintenance cycles may be dispensed with for the RTO device 110. In addition to a disposal as required of the fluid flows 101 and 102, the operational costs and/or availability for the RTO device 110 may be improved by the additional second combustion chamber 120 for disposal of the second fluid flow 102. In other words: The second fluid flow 102 may contain a polluting substance and/or a substance damaging the at least one regenerator 112, while the first fluid flow 101 contains no or less (e.g., at least 5, 10, 100, or 1000 times less than the second fluid flow 102) polluting substances and/or substances damaging the at least one regenerator 112.
As already described above, the temperature in the second combustion chamber 120 is passively set via the process heat 103 transported from the RTO device 110 to the second combustion chamber 120. According to embodiments, the temperature in the second combustion chamber 120 may be set exclusively passively via the process heat 103 transported from the RTO device 110 to the second combustion chamber 120, i.e. without an additional burner in the second combustion chamber 120 or other external heat supply. In other words: According to embodiments, the second combustion chamber 120 may not have its own burner. The second combustion chamber 120 may alternatively comprise at least one burner (not shown in
In order to ensure that a temperature required for thermal oxidation in the first combustion chamber 111 is reached, the heat transport device 130 may be configured to dissipate the process heat 130 from the RTO device 110 only after a predetermined temperature has been reached in the first combustion chamber 111. In other words: The heat transport device 130 dissipates (substantially) no process heat from the RTO device 110 prior to reaching the predetermined temperature in the first combustion chamber 111.
The heat transport device 130 may dissipate the process heat 103 from the RTO device 110 in a variety of ways. For example, the heat transport device 130 may be configured to transport the process heat 103 in the form of flue gas from the RTO device 110 to the second combustion chamber 120. For example, the heat transport device 130 may be coupled to the combustion chamber 111 or another element of the RTO device 110 to dissipate flue gas from the RTO device 110 and route it to the second combustion chamber 120 in a controlled manner. The hot flue gas may flow through the second combustion chamber 120 accordingly in order to set the temperature in the second combustion chamber 120.
For controlling the temperature in the second combustion chamber 120, the heat transport device 130 may, for example, be configured to set a volume flow of the flue gas transported from the RTO device 110 to the second combustion chamber 120 depending on the temperature in the second combustion chamber 120 and/or a predetermined range of values to which the temperature in the second combustion chamber 120 is to be set. In other words: The amount of flue gas supplied per time unit and thus the amount of heat supplied per time unit may be set depending on an actual temperature in the second combustion chamber 120 and/or a target temperature and/or a target temperature range for the second combustion chamber 120. For example, the heat transport device 130 may comprise, in addition to one or more (e.g. heat insulated) lines for transporting the flue gas, one or more controllable control flaps (or alternatively valves) for setting the volume flow. Likewise, the heat transport device 130 may comprise one or more sensors for measuring the volume flow and further parameters of the flue gas (e.g. temperature), if applicable.
However, the heat transport device 130 is not limited to the transport of process heat 103 in the form of flue gas. Alternatively, the process heat 103 of the RTO device 110 may also be transported from the RTO device 110 to the second combustion chamber 120 by means of another medium and used there for setting the temperature in the second combustion chamber 120. For example, the heat transport device 130 may be configured to warm up a separate fluid for heat transport (e.g. a gas such as air or a liquid such as water or thermo-oil and/or thermal oil) by means of the process heat 103, to transport the warmed-up fluid to the second combustion chamber 120 and to release the process heat stored in the warmed-up fluid to the second combustion chamber 120 in order to set the temperature in the second combustion chamber 120. To warm up the fluid, the heat transport device 130 may, for example, comprise one or more heat exchangers. In an analogous way, the heat transport device 130 may comprise one or more heat exchangers for releasing the process heat 103 stored in the warmed-up fluid to the second combustion chamber 120. In addition to one or more (e.g., heat insulated) lines for transporting the warmed-up fluid, the heat transport device 130 may comprise one or more controllable control flaps (or alternatively valves) for setting a volume flow of the fluid from the RTO device 110 to the second combustion chamber. The volume flow of the fluid may in turn be set depending on the temperature in the second combustion chamber 120 and/or a predetermined range of values to which the temperature in the second combustion chamber 120 is to be set.
Similarly, the heat transport device 130 may also be configured, for example, as a heat conductor or thermocoupler to transport the process heat 103 of the RTO device 110 from the RTO device 110 to the second combustion chamber 120.
In order to ensure safe thermal oxidation of the first fluid flow 101 in the RTO device 110, the fluid purification system 100 may also be configured to supply the first fluid flow 101 to the RTO device 110 only after a first predetermined temperature or a first predetermined temperature range has been reached in the first combustion chamber 111. For example, the first predetermined temperature and/or the first predetermined temperature range in the first combustion chamber 111 may be selected such that a temperature necessary for thermal oxidation in the first combustion chamber 111 is reached and/or exceeded. The fluid purification system 100 may comprise, for example, a first fluid supply device (not shown in
Similarly, the fluid purification system 100 may be configured to supply the second fluid flow 102 to the second combustion chamber 120 only after a second predetermined temperature or a second predetermined temperature range has been reached in the second combustion chamber 120. Accordingly, safe thermal oxidation of the second fluid flow 102 in the second combustion chamber 120 may be ensured. For example, the second predetermined temperature and/or the second predetermined temperature range in the second combustion chamber 120 may be selected such that a temperature necessary for thermal oxidation in the second combustion chamber 120 is reached and/or exceeded. The fluid purification system 100 may, for example, comprise a second fluid supply device (not shown in
The second combustion chamber 120 may be arranged in close proximity to the RTO device 110 or further away from it. For example, the second combustion chamber 120 may be arranged on the RTO device 110, i.e., above the RTO device 110. In other words: The second combustion chamber 120 may be arranged on or above a top of the RTO device 110. An arrangement of the second combustion chamber 120 in close proximity to the RTO device 110 may be advantageous with respect to the transport of the process heat 103 from the RTO device 110 to the second combustion chamber 120 due to the lower heat losses during the transport of the process heat 103 as a result of the smaller distance.
To control one or more of its constituents (e.g., the RTO device 110, the second combustion chamber 120, or the heat transport device 130), the fluid purification system 100 may further comprise a control circuit (not shown in
Similarly, the control circuit may be configured to control the one and/or more constituents of the fluid purification system 100 such that a first predetermined dwell period of the first fluid flow 101 in the first combustion chamber 111 is not undercut. In an analogous manner, the control circuit may be configured to control the one and/or more constituents of the fluid purification system 100 such that a second predetermined dwell period (dwell time) of the second fluid flow 102 in the second combustion chamber is not undercut. The term “dwell period” refers to the respective residence period (residence time) of the fluid flow to be treated in the respective combustion chamber 111 and/or 120 (i.e. the respective reaction space). By keeping the respective fluid flow in the respective combustion chamber for at least the respective dwell period, sufficient thermal oxidation of the respective fluid flow and thus compliance with the required maximum pollutant values in the respective flue gas may be ensured.
The control circuit may be formed by and/or comprise a processor, a computer processor (CPU=Central Processing Unit), a computer, a computer system, an application-specific integrated circuit (ASIC), an integrated circuit (IC), a system on a chip (SoC), a programmable logic element, a field programmable gate array (FPGA) with a microprocessor, a back-end or a compute cloud on which software for controlling the one and/or more constituents of the fluid purification system 100 runs according to the principles described herein. Furthermore, the control circuit may have and/or be coupled to one or more memories.
The first fluid flow 101 and the second fluid flow 102 may, for example, originate from an industrial plant or an industrial process, such as in the chemical, petrochemical, pharmaceutical or solvent-processing industry.
In the example of
A first fluid flow 201 may be supplied to the 3-tower RTO device 210 via a first fluid supply device 240 of the fluid purification system 200, which comprises at least one line 241 and the valves 242, 243 and 244.
The first fluid flow 201 is first routed through the regenerator 212-1 by means of the valve 242, where the first fluid flow 201 is warmed up by the heat stored in the regenerator 212-1 and finally reaches the first combustion chamber. Thereby, the valves 243 and 244 are closed such that the first fluid flow 201 cannot flow through the regenerators 212-2 and 212-3. The first combustion chamber 211 was heated in advance by the two burners 213-1 and 213-2 to a predetermined temperature and/or a predetermined temperature range, such that the warmed-up first fluid flow 201 finally oxidizes to water and carbon dioxide.
The hot flue gas obtained during oxidation is then routed through one of the other two regenerators 212-2 and 212-3 by opening one of the valves 215 and 216. In the following, it is assumed that the hot flue gas is routed through the regenerator 212-2. Thereby, the hot flue gas releases a large part of its thermal energy to the regenerator 212-2, such that this is heated and/or warmed up and may be used to warm up the first fluid flow 201 in a subsequent second cycle.
During the second cycle, by opening the valve 215, the first fluid flow 201 is routed through the regenerator 212-2 preheated in the first cycle in order to warm up the first fluid flow 201 in the second cycle by the heat stored in the preheated regenerator 212-2. The warmed-up first fluid flow 201 is then thermally oxidized in the first combustion chamber 211 as in the first cycle, and the flue gas obtained thereby is routed through the regenerator 212-3 by opening the valve 216. Thereby, the hot flue gas releases a large part of its thermal energy to the regenerator 212-3, such that this is heated and/or warmed up and may be used to warm up the first fluid flow 201 in a subsequent third cycle.
During the third cycle, by opening the valve 216, the first fluid flow 201 is routed through the regenerator 212-3 preheated in the second cycle to warm up the first fluid flow 201 in the third cycle by the heat stored in the preheated regenerator 212-3. The warmed-up first fluid flow 201 is then thermally oxidized in the first combustion chamber 211 as in the preceding cycles, and the flue gas obtained thereby is routed through the regenerator 212-1 by opening the valve 214. In doing so, the hot flue gas releases a large part of its thermal energy to the regenerator 212-1, such that it is heated and/or warmed up and may be used to warm up the first fluid flow 201 as described above.
The valves 214, 215 and 216 form a respective outlet of the 3-tower RTO device 210 for dissipating the flue gas.
A purge gas 256 (e.g. air) may be supplied to the 3-tower RTO device 210 via a purge gas supply device 250, which comprises at least a line 255, a blower (and/or fan) 251 and the control flaps 252, 253 and 254. During the first cycle, the control flap 254 is opened for this purpose in order to purge remaining flue gas from the regenerator 212-3 by means of the purge gas 256 from a previous cycle. Thereby, the control flaps 252 and 253 are closed such that the purge gas 256 cannot flow through the regenerators 212-1 and 212-2. Similarly, during the second cycle, the control flap 252 is opened to purge any remaining flue gas from the first cycle from the regenerator 212-1 by means of the purge gas 256, and during the third cycle, the control flap 253 is opened to purge any remaining flue gas from the second cycle from the regenerator 212-2 by means of the purge gas 256.
The three cycles are repeated continuously to alternately cool one of the regenerators 212-1, 212-2 and 212-3, warm up another one of the regenerators 212-1, 212-2 and 212-3 and purge a third one of the regenerators 212-1, 212-2 and 212-3. Accordingly, the first fluid flow 201 may be cleaned by means of RTO by the RTO device 210.
It should be noted that the purging of the regenerators 212-1, 212-2 and 212-3 with fresh air (also referred to as “fresh air injection”) shown in
A plurality of sensors 219 are arranged in and/or at the individual towers to monitor the 3-tower RTO device 210. For example, one or more of the plurality of sensors 219 may be sensors for measuring a respective temperature, a respective volume flow, a respective pollutant concentration, etc. Similarly, one or more further sensors may be attached in and/or at the first combustion chamber 211.
After heating up the 3-tower RTO device 210, combustion of the additional substance by the two burners 213-1 and 213-2 is only required during a sub-autothermal operation of the 3-tower RTO device 210. In sub-autothermal operation, the fuel requirement needed to maintain the temperature necessary for thermal oxidation in the first combustion chamber 211 is not covered by the enthalpy of reaction of the ingredients of the first fluid flow 201. In other words: The energy content of the first fluid flow 201 is not sufficient to maintain the thermal oxidation process. During an autothermal operation of the 3-tower RTO device 210, the fuel requirement needed to maintain the temperature necessary for thermal oxidation in the first combustion chamber 211 is covered by the enthalpy of reaction of the ingredients of the first fluid flow 201. In other words: The energy content of the first fluid flow 201 is sufficient to maintain the thermal oxidation process. In over-autothermal operation of the 3-tower RTO device 210, the fuel requirement needed to maintain the temperature necessary for thermal oxidation in the first combustion chamber 211 is more than covered by the enthalpy of reaction of the ingredients of the first fluid flow 201. In other words: The energy content of the first fluid flow 201 is higher than necessary to maintain the thermal oxidation process. During autothermal as well as during over-autothermal operation of the 3-tower RTO device 210, the combustion of additional fuel by the two burners 213-1 and 213-2 may therefore be stopped and/or the two burners 213-1 and 213-2 may be operated at minimum flame.
In order to avoid overheating of the regenerators 212-1, 212-2 and 212-3 during over-autothermal operation of the 3-tower RTO device 210, the 3-tower RTO device 210 comprises a bypass 217 with a controllable control flap 218. The bypass 217 is configured to dissipate a part of the flue gas obtained during RTO past the respective regenerators 212-1, 212-2 and/or 212-3 and out of the 3-tower RTO device 210. The bypass 217 may also be referred to as a “hot bypass”, as the flue gas routed through the bypass 217 is significantly hotter than the flue gas dissipated through the valves 214, 215 and 216. Via the control flap 218, a volume flow of the flue gas through the bypass 217 and thus the amount of flue gas routed past the respective regenerators 212-1, 212-2 and/or 212-3 per time unit may be controlled. The amount of flue gas dissipated per time unit from the 3-tower RTO device 210 by means of the bypass 217 may be, for example, a maximum of 30%, 25%, 20%, 15% or 10% of the flue gas obtained per time unit during RTO. In other words: In some embodiments, the amount of the volume flow discharged via the hot bypass 217 is no more than 30% (or preferably 20%). As a result, uneven distributions of temperature in the regenerators 212-1, 212-2 and/or 212-3 may be avoided.
The fluid supply device 240 further comprises a control flap 245, which is configured to supply fresh air 206 to the first fluid flow 201 in a controlled and thus selective manner. The concentration of pollutants in the first fluid flow 201 may be reduced and/or set via the supply of fresh air 206. By supplying the fresh air 206, the first fluid flow 201 may be safely disposed of by the 3-tower RTO device 210 even with a higher load of pollutants and/or flammable substances due to the dilution thus achieved.
The fluid purification system 200 further comprises a second combustion chamber 220 separate from the 3-tower RTO device 210. Via a second fluid supply device in the form of a control flap 260, a second fluid flow 202 different from the first fluid flow 201 may be supplied to the second combustion chamber 220. The second combustion chamber 220 is configured to purify the second fluid flow 202 by means of (direct) thermal oxidation. Furthermore, the fluid purification system 200 comprises a second combustion air supply device in the form of a control flap 285, which is configured to feed second combustion air 208 into the second combustion chamber 220 in a controlled and thus selective manner.
To monitor the second combustion chamber 220, a plurality of sensors 221 are arranged in and/or at the second combustion chamber 220. For example, one or more of the plurality of sensors 221 may be sensors for measuring a respective temperature, a respective volume flow, a respective pollutant concentration, etc.
In addition, the fluid purification system 200 comprises a heat transport device 230 which comprises at least one line 231 and a control flap 232. The heat transport device 230 is configured to transport process heat in the form of flue gas 203 from the 3-tower RTO device 210 to the second combustion chamber 220 to set a temperature in the second combustion chamber 220. The flue gas 203 flows through the second combustion chamber 220 accordingly in order to set the temperature in the second combustion chamber 220. In the embodiment of
In the example of
The volume flow of the flue gas 203 transported from the 3-tower RTO device 210 to the second combustion chamber 220 may be controlled by the control flap 232. The heat transport device 230 and/or the control flap 232 may, for example, be configured to set the volume flow of the flue gas transported from the 3-tower RTO device 210 to the second combustion chamber 220 depending on the temperature in the second combustion chamber 220 and/or a predetermined range of values to which the temperature in the second combustion chamber 220 is to be set. In other words: The amount of flue gas 203 supplied per time unit and thus the amount of heat supplied per time unit may be set depending on an actual temperature in the second combustion chamber 220 and/or a target temperature and/or a target temperature range for the second combustion chamber 220.
When the first combustion chamber 211 is heated to the required operating temperature (e.g., above 800° C.), the first fluid flow may be disposed 201 through the 3-tower RTO device 210 by alternately opening one of the valves 242, 243, and 244 in accordance with the principles described above. Similarly, when the second combustion chamber 220 is heated to the required operating temperature (e.g., above 800° C.), the second fluid flow 202 may be disposed through the second combustion chamber 220 by opening the control flap 260. In other words: The first fluid supply device, which comprises the valves 242, 243 and 244, may be configured to supply the first fluid flow 201 to the 3-tower RTO device 210 only after a first predetermined temperature has been reached in the first combustion chamber 211. Similarly, the second fluid supply device comprising the control flap 260 may be configured to supply the second fluid flow 202 to the second combustion chamber 220 only after a second predetermined temperature has been reached in the second combustion chamber 220. If necessary, first combustion air 209 may be fed into the first combustion chamber 211 in a controlled manner via the first combustion air supply device formed by the control flap 280 and/or second combustion air 208 may be fed into the second combustion chamber 220 in a controlled manner via the second combustion air supply device formed by the control flap 285.
Thereby, the control flap 218 may be slowly throttled down to a minimum flow rate if no further heating of the second combustion chamber 220 is required.
As already indicated in connection with
The 3-tower RTO device 210 may be started up regularly to heat up the first combustion chamber 211. In other words: The two burners 213-1 and 213-2 are arranged to burn the additional fuel during heating of the 3-tower RTO device 210 to set the temperature in the first combustion chamber 211 to a predetermined value or range of values. Thereby, the control flap 218 in the bypass 217 may initially be throttled back to the maximum and used to regulate the pressure in the first combustion chamber 211 when combustion of the additional fuel starts. As already described above, in the 3-tower RTO device 210, disposal of the first fluid flow only takes place after the operating temperature has been reached, i.e. after the predetermined temperature value and/or temperature value range has been reached. After setting the temperature in the first combustion chamber 211 to the predetermined value and/or range of values, the valves 214, 215 and 216, which serve as outlets for dissipating flue gas from the 3-tower RTO device 210, are (slightly) opened to generate a volume flow of the flue gas obtained by burning the additional fuel through the regenerators 212-1, 212-2 and 212-3. The ceramic material in the regenerators 212-1, 212-2 and 212-3 is slowly warmed up by the flue gas flowing through the regenerators 212-1, 212-2 and 212-3.
In order to dissipate the flue gas from the 3-tower RTO device 210, a negative pressure is generated in the first combustion chamber 211 by means of a suction draft 270. The induced draft 270 is coupled to the 3-tower RTO device 210 via the valves 241, 215 and 216 and generates a flow of flue gas from the 3-tower RTO device 210 to the induced draft 270. The induced draft 270 accordingly emits a flue gas flow 299. One or more sensors 271 for measuring parameters relating to the at least one flue gas flow (e.g. temperature and/or volume flow of the flue gas flow) are attached in and/or at the induced draft 270.
After the first combustion chamber 211 and the regenerators 212-1, 212-2 and 212-3 have been heated up, the second combustion chamber 220 may be heated. As already explained above, the control flap 232 is opened for this purpose in order to route the flue gas from the first combustion chamber 211 to the second combustion chamber 220, such that the flue gas flows through the latter and warms it up. In other words: The heat transport device 230 is configured to dissipate the process heat in the form of the flue gas 203 from the 3-tower RTO device 210 only after a predetermined temperature has been reached in the first combustion chamber 211. When heating up the second combustion chamber 220, the control flap 218 may be throttled back accordingly.
As can be seen from
The fluid purification system 200 further comprises a fresh air supply device in the form of a control flap 290. The control flap 290 is arranged between the induced draft 270 and both the 3-tower RTO device 210 and the second combustion chamber 220 and is configured to supply fresh air 207 in a controlled manner to the flue gas flow and/or flows leading to the induced draft 270. In particular, the control flap 290 may be configured to supply the fresh air 207 to the at least one flue gas flow depending on its temperature. The temperature upstream of the induced draft may be regulated via the fresh air supply. Due to the temperature regulation, the induced draft 270 may be configured in a lower temperature class, for example.
According to embodiments, the thermal design of the 3-tower RTO device 210 is such that both the first combustion chamber 211 of the 3-tower RTO device 210 and the second combustion chamber 220 may be heated by means of the appropriately dimensioned burners 213-1 and 213-2. Thereby, the dimensioning of the first combustion chamber 211 and/or the regenerators 212-1, 212-2 and 212-3 may be carried out according to the requirements of the first fluid flow 201 (e.g. depending on an expected volume flow of the first fluid flow 201 and/or a desired dwell period of the first fluid flow in the first combustion chamber 211). The influence on the RTO may be minimized in this way.
The dimensioning of the second combustion chamber 220 as well as the heat transport device 230 and, if applicable, of the bypass 217 may be carried out according to the requirements of a directly fired combustion chamber. In particular, a desired and/or required dwell period of the second fluid flow in the second combustion chamber 220 may influence the dimensioning of the second combustion chamber 220.
The pressure ratios in the 3-tower RTO device 210 and the second combustion chamber 220 are set such that gas cannot flow back from the second combustion chamber 220 into the 3-tower RTO device 210.
To control one or more of its constituents (e.g., the 3-tower RTO device 210, the second combustion chamber 220, or the heat transport device 230), the fluid purification system 200 may also further comprise a corresponding control circuit (not shown in
In particular, the control circuit may be configured to control the one and/or more constituents of the fluid purification system 200 such that a first predetermined dwell period of the first fluid flow 201 in the first combustion chamber 211 is not undercut. In an analogous manner, the control circuit may be configured to control the one and/or more constituents of the fluid purification system 200 such that a second predetermined dwell period (dwell time) of the second fluid flow 202 in the second combustion chamber 220 is not undercut. By compliance with the respective dwell period, sufficient thermal oxidation of the respective fluid flow 201 and/or 202 and thus compliance with the required maximum pollutant values in the respective flue gas may be ensured.
As an alternative to the negative pressure operation by means of induced draft 270 shown in
Furthermore, one or more sensors 371 and/or 376 for measuring parameters relating to the respective fluid flow 201 and/or 202 (e.g. temperature, composition and/or volume flow of the fluid flow) are attached in and/or at the respective blower and/or fan 370 and/or 375.
Other than that, the fluid purification system 300 is identical to the above-described fluid purification system 200.
In order to summarize the aspects of fluid purification described above,
The method 400 allows a synergistic use of direct thermal oxidation and RTO to enable safe and economical operation. The additional combustion space provided by the second combustion chamber may be warmed up with the process heat of the RTO device in order to safely oxidize not only the first fluid flow but also, for example, a second fluid flow which is highly calorific and/or loaded with corrosive substances in the second combustion chamber.
More details and aspects of the method 400 are described above in connection with further embodiments (e.g.
For example, according to the method 400, the temperature in the second combustion chamber in the method step 406 may be (e.g., exclusively) passively set by means of the process heat transported from the RTO device to the second combustion chamber.
As explained in more detail above, the process heat according to the method 400 may only be transported from the RTO device to the second combustion chamber after a predetermined temperature has been reached in the first combustion chamber. Accordingly, reaching the temperature required for thermal oxidation in the first combustion chamber may be ensured.
Similarly, the method 400 may further comprise, for example, supplying 408 the first fluid flow to the RTO device only after a first predetermined temperature has been reached in the first combustion chamber. Alternatively or additionally, the method 400 may comprise supplying 410 the second fluid flow to the second combustion chamber only after a second predetermined temperature has been reached in the second combustion chamber. Accordingly, reaching a respective temperature required for thermal oxidation in the RTO device and/or the second combustion chamber and thus a reliable thermal oxidation of the respective fluid flow may be ensured.
As discussed in more detail above in connection with
The optional features and/or method steps of the method 400 described above are chosen only for a better understanding of the method 400. It is understood that the method 400 may also include any of the other features described above in connection with
The aspects and features described in relation to a particular one of the previous examples may also be combined with one or more of the further examples to replace an identical or similar feature of that further example or to additionally introduce the feature into the further example.
It is further understood that the disclosure of several steps, processes, operations or functions disclosed in the description or claims shall not be construed to imply that these operations are necessarily dependent on the order described, unless explicitly stated in the individual case or necessary for technical reasons. Therefore, the previous description does not limit the execution of several steps or functions to a certain order. Furthermore, in further examples, a single step, function, process, or operation may include and/or be broken up into several sub-steps, -functions, -processes or -operations.
If some aspects in the previous sections have been described in relation to an apparatus or system, these aspects should also be understood as a description of the corresponding method. In this case, for example, a block, an apparatus or a functional aspect of the device or system may correspond to a feature, such as a method step, of the corresponding method. Accordingly, aspects described in relation to a method shall also be understood as a description of a corresponding block, a corresponding element, a property or a functional feature of a corresponding device or a corresponding system.
The following claims are hereby incorporated in the detailed description, wherein each claim may stand on its own as a separate example. It should also be noted that although in the claims a dependent claim refers to a particular combination with one or more other claims—other examples may also include a combination of the dependent claim with the subject matter of any other dependent or independent claim. Such combinations are hereby explicitly proposed, unless it is stated in the individual case that a particular combination is not intended. Furthermore, features of a claim should also be included for any other independent claim, even if that claim is not directly defined as dependent on that other independent claim.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 125 432.9 | Sep 2021 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/DE2022/100726 | 9/29/2022 | WO |
