Regenerative incineration system with online anti-burning function and control mode thereof

Abstract

The present application relates to a heat accumulating incineration system with online reverse burning function and a working method thereof, the system comprising a heat accumulating thermal oxidizer, the heat accumulating thermal oxidizer being provided with 3N+M gas collecting heat accumulating chambers, in a normal working state, the gas collecting heat accumulating chambers are divided into three working groups and one standby group, the number of gas collecting heat accumulating chambers in each working group is N, and the number of gas collecting heat accumulating chambers in the standby group is M, the gas collecting heat accumulating chambers needing reverse burning in the standby group are subjected to online reverse burning, and the temperature of the heat accumulating layer of the gas collecting heat accumulating chambers subjected to online reverse burning is adjusted by adjusting the air outlet valve and the purge valve, so that the required temperature is reached. The incineration system allows the heat accumulating thermal oxidizer to be subjected to online reverse burning, thereby avoiding the adverse effects on production caused by offline reverse burning.

Description

Technical Field

[0001] This invention relates to a regenerative thermal incineration system with online reverse combustion function and its control method, which can be mainly used for the thermal oxidation treatment of industrial organic waste gas. Background Technology

[0002] A regenerative thermal oxidizer (RTO) is a highly efficient and energy-saving organic waste gas treatment device. It has multiple gas-collecting regenerator chambers (also called regenerator chambers) below the combustion chamber. The upper part of the gas-collecting regenerator chamber is called the regenerator chamber, which is a regenerator layer formed by regenerator materials such as regenerator ceramics. The lower part is called the gas-collecting chamber, used for equal pressure distribution of inlet and outlet gases. Waste gas enters from the bottom of the gas-collecting regenerator chamber, is heated by the regenerator layer, and then enters the combustion chamber, where it undergoes high-temperature oxidation or combustion. The waste gas then enters another gas-collecting regenerator chamber from the top, flowing through the regenerator layer and heating the regenerator material. Through related piping and valves, the operating states of each gas-collecting regenerator chamber are periodically switched, continuously absorbing the heat energy of the outlet gas and heating the inlet gas. This achieves efficient utilization of the heat of reaction, meeting the temperature requirements of the combustion chamber with relatively low fuel consumption.

[0003] Currently, most RTOs widely used in my country adopt a three-chamber structure, with three heat storage chambers. Under normal operating conditions, the three heat storage chambers are in three states: air intake, air exhaust, and purging, respectively. These three operating states can be switched between the three heat storage chambers by valve switching.

[0004] However, due to the characteristics of the exhaust gas, scale often forms on the lower part of the heat storage layer, clogging the airflow channels within it. When the blockage reaches a certain level, the regenerative incineration system will cease to function properly. Currently, a method known as reverse combustion is used to solve this blockage problem. This involves heating the lower part of the heat storage layer to burn off the scale on the surface of the heat storage material, restoring the original airflow channels.

[0005] Existing reverse combustion methods are mostly offline. For example, Chinese patent document CN211411518U discloses a three-chamber offline reverse combustion device for an RTO. An oxidation chamber is located on the upper outer surface of the gas collecting and heat storage chamber, and a burner is installed inside the oxidation chamber. A gas distribution chamber is located on the lower outer surface of the gas collecting and heat storage chamber, and an inlet pipe and a bypass pipe are located on the lower outer surface of the gas distribution chamber. The inlet pipe is located to one side of the bypass pipe, and an exhaust gas outlet valve and an exhaust gas inlet valve are located on the front outer surface of the inlet pipe. The exhaust gas outlet valve is located to one side of the exhaust gas inlet valve. The device includes a gas distribution chamber and a differential pressure transmitter, which facilitates heat exchange and heating of the exhaust gas, thus aiding in the treatment of oily gases. It also measures pressure, making it convenient for operators to adjust the device. This addresses the issue of resistance in the gas collecting and heat storage chamber due to blockage (due to the pressure difference between the inlet and outlet of the gas collecting and heat storage chamber or the pressure difference between the inlet and outlet of the equipment). When the exhaust pressure difference reaches a certain level, offline reverse combustion is performed. The working principle is as follows: First, the exhaust gas enters through the inlet pipe, and the differential pressure of the heat accumulator is measured by the differential pressure transmitter. When the differential pressure reaches 2000Pa, the switching time of each chamber is extended to raise the temperature of the flue gas distribution chamber to 300℃. This continues until the differential pressure returns to normal, and then the RTO continues to operate normally. Then, when the differential pressure reaches 3000Pa, the exhaust gas inlet valve is closed, and the RTO is taken offline. The exhaust gas enters the bypass and is discharged into the atmosphere after being adsorbed by activated carbon. When the exhaust gas inlet valve is closed, the burner continues to work, and the exhaust gas outlet valve is opened to raise the temperature of the lower chamber to 300℃. This continues until the differential pressure returns to normal, and then the RTO continues to operate normally. During offline or abnormal operation, the exhaust gas often fails to meet emission standards, and the production line may even be forced to shut down due to the ineffective treatment of the exhaust gas.

[0006] Online reverse combustion methods have also been proposed. For example, Chinese patent document CN214223125U discloses an automatic reverse combustion system for RTO coking, including a furnace body. The interior of the furnace body is divided into several groups of ceramic beds by several sets of partitions at equal intervals. A honeycomb heat storage body is provided in the ceramic beds. An oxidation chamber is formed above the honeycomb heat storage body, and a distribution chamber is formed below the honeycomb heat storage body. Thermocouples are connected to the upper and lower ends of the honeycomb heat storage body, respectively. Several sets of burners are connected to the upper end of the furnace body at equal intervals. A combustion pump is connected to the upper end of the burner. A gas pipe is connected to the upper end of the combustion pump. A reverse combustion pipe is also connected to one end of the burner. A first air inlet pipe is connected to one side of the reverse combustion pipe. A reverse combustion fan is also connected to the reverse combustion pipe. One end of the reverse combustion pipe is connected to the lower part of the furnace body through a reverse combustion branch pipe and is located at the lower end of the distribution chamber. During operation, after preheating, the three ceramic beds inside the furnace operate in a one-in-one-out-one-purge mode. The exhaust gas inlet pipe is connected to the furnace body, and the exhaust gas first enters the No. 1 ceramic bed on the left for preheating. After being fully oxidized in the combustion chamber, it is discharged from the chimney through the No. 2 ceramic bed in the middle. The No. 3 ceramic bed on the right is in the purging stage. After the first operating cycle is completed, the valve is switched, and the exhaust gas enters the No. 2 ceramic bed for preheating. After being fully oxidized in the combustion chamber, it is discharged from the No. 3 ceramic bed through the exhaust pipe until the second operating cycle is completed. During this period, the No. 1 ceramic bed is in the purging stage. This process continues until the third cycle is completed. The exhaust gas enters and exits in a cycle between the three ceramic beds, completing the continuous operation of the RTO furnace body. When the pressure difference between the furnace inlet and outlet exceeds a certain value (over 3000 Pa), indicating increased bed resistance (ammonium salts at the bottom of the ceramic bed clogging the ceramics), the system will prompt the user to enter the reverse firing stage. One end of the burner is connected to a reverse firing pipe, one side of which is connected to a first air inlet pipe. A reverse firing fan is also connected to the reverse firing pipe. One end of the reverse firing pipe is connected to the bottom of the furnace body via reverse firing branch pipes, located at the lower end of the distribution chamber. The reverse firing pipe supplies air to one of the three ceramic beds in the furnace. This ceramic bed undergoes gradual reverse firing at a certain temperature gradient (overall ceramic bed temperature 200℃, 250℃, 350℃), maintaining each temperature for 30 to 60 minutes to ensure that all the condensed gel is vaporized or oxidized, thus cleaning the ceramic bed. The three beds are reverse fired alternately. Once the gel reaches a certain level, the equipment automatically executes the reverse firing program. Operators can also click the reverse firing button to automatically clean the ceramic bed if they deem it necessary.However, since only the remaining two ceramic beds are used for exhaust gas treatment during reverse combustion, these two chambers can only switch between intake and exhaust states. After the exhaust gas enters the regenerative oxidizer, it will directly switch to exhaust state without purging in the next cycle. At this time, some exhaust gas remaining at the bottom of the gas collection chamber and the gas collection regenerator chamber cannot be treated, resulting in the exhaust gas exceeding the standard. In addition, since a special pipeline is set up to introduce the high-temperature gas from the combustion chamber into the bottom of the gas collection regenerator chamber, the pipelines and switching / control valves on the reverse combustion pipeline must be adapted to the high temperature of the combustion chamber exhaust gas, which increases the additional cost and seriously hinders the promotion and application of this online reverse combustion in practice. Summary of the Invention

[0007] The purpose of this invention is to allow regenerative thermal oxidizers to undergo online back-burning, thereby avoiding the adverse effects on production caused by offline back-burning.

[0008] The technical solution of the present invention is: a regenerative thermal oxidizer with online reverse combustion function, including a regenerative thermal oxidizer (RTO). The regenerative thermal oxidizer is provided with a number of gas collection and heat storage chambers, the number of which is 3N+M (N and M are both positive integers). The combustion chamber of the regenerative thermal oxidizer is connected to a high-temperature thermal bypass pipe. A bypass valve is provided on the high-temperature thermal bypass pipe. Both the high-temperature thermal bypass pipe and the gas outlet pipe of the regenerative thermal oxidizer are connected to a high-temperature gas mixing device. The gas outlet pipeline of the high-temperature gas mixing device is connected to the gas inlet of the quench tower.

[0009] Furthermore, the purge pipe of the regenerative thermal oxidizer is connected to each gas collecting and heat storage chamber through several purge branch pipes. The purge branch pipes can be connected to their respective gas collecting and heat storage chambers by directly connecting to the bottom of the corresponding gas collecting and heat storage chamber, or by connecting to the inlet branch pipe on the gas collecting and heat storage chamber side of the corresponding gas collecting and heat storage chamber located at the inlet valve and the outlet branch pipe on the gas collecting and heat storage chamber side of the outlet valve respectively through two purge connection pipes.

[0010] Furthermore, the air inlet pipe of the regenerative thermal oxidizer is connected to each gas collection and heat storage chamber through several air inlet branch pipes, and a front-mounted main fan is provided on the air inlet pipe.

[0011] Furthermore, a flame arrester is provided on the air intake pipe.

[0012] The flame arrester is preferably located between the front main fan and the air intake branch pipe.

[0013] Furthermore, a steam heat exchanger is connected to the air inlet pipe.

[0014] The steam heat exchanger can be a gas-to-gas heat exchanger with steam as the heat release medium, or it can be other types of heaters (for the sake of simplicity, they are collectively referred to as steam heat exchangers).

[0015] The steam heat exchanger is preferably located on the air inlet side of the front main fan.

[0016] Furthermore, a main intake shut-off valve is connected to the intake pipe.

[0017] The main inlet shut-off valve is preferably located on the inlet side of the steam heat exchanger, and the inlet side of the main inlet shut-off valve is used to connect the gas pipeline to be treated.

[0018] The control method of a regenerative thermal oxidizer with online reverse combustion function, or the working method of a regenerative thermal oxidizer with online reverse combustion function, wherein the regenerative thermal oxidizer with online reverse combustion function adopts any of the regenerative thermal oxidizers with online reverse combustion function disclosed in this invention, including a regenerative thermal oxidizer, wherein the regenerative thermal oxidizer has 3N+M gas collection and heat storage chambers, where N and M are both positive integers. Under normal working conditions, the gas collection and heat storage chambers are divided into three working groups and one standby group, and the number of gas collection and heat storage chambers in each working group is N. When N is greater than At time 1, the working status of each gas-collecting heat storage chamber in the same working group is consistent, and they are switched synchronously to maintain the same working status. The number of gas-collecting heat storage chambers in the standby group is M. Online back-burning is implemented for the gas-collecting heat storage chambers in the standby group that need back-burning. The temperature of the heat storage layer of the gas-collecting heat storage chambers that are back-burning is adjusted by adjusting the air outlet valve and purge valve of the gas-collecting heat storage chambers that are back-burning, so that they reach and maintain the temperature required for back-burning. The gas-collecting heat storage chambers in the standby group that do not need back-burning remain in a stopped state. Each gas-collecting heat storage chamber rotates between the working group and the standby group in sequence.

[0019] Preferably, during the entire reverse combustion process, the inlet valve of the reverse combustion gas collection and heat storage chamber is closed. At the initial stage of reverse combustion, the outlet valve of the online reverse combustion gas collection and heat storage chamber is opened, and the purge valve is closed, allowing the high-temperature airflow from the combustion chamber to pass through the corresponding gas collection and heat storage chamber, causing the heat storage material in the corresponding gas collection and heat storage chamber to absorb heat and rise in temperature until the reverse combustion temperature is reached. The reverse combustion temperature is maintained for a certain period of time until the reverse combustion purpose is achieved (to obtain the desired reverse combustion effect). The reverse combustion temperature is maintained by opening the outlet valve and closing the purge valve when it is necessary to raise the temperature (e.g., when the actual temperature drops below the required reverse combustion temperature, or when it is necessary to raise the reverse combustion temperature), allowing the high-temperature airflow from the combustion chamber to pass through the corresponding gas collection and heat storage chamber. When it is necessary to lower the temperature (e.g., when the actual temperature rises above the required reverse combustion temperature, or when it is necessary to lower the reverse combustion temperature), closing the outlet valve and opening the purge valve, allowing external purge air to pass through the corresponding gas collection and heat storage chamber.

[0020] Furthermore, at the end of the reverse combustion stage (after achieving the reverse combustion objective / obtaining the desired reverse combustion effect), the outlet valve is closed and the purge valve is opened, allowing external purge gas to pass through the corresponding gas collection and heat storage chamber, causing the heat storage material in the corresponding gas collection and heat storage chamber to release heat and heat up until the standby temperature is reached.

[0021] Preferably, for any working group, the purging state is entered after both the intake state and the exhaust state are completed.

[0022] The duration of the purging state is half the duration of the intake state, and the durations of the intake and exhaust states are the same. The durations of the same state are consistent for all working groups.

[0023] Preferably, for any working group, when its air intake state is halfway through (half the time), the working state of the other two working groups is switched (from air outlet state to purging state, or from purging state to air outlet state). When its air intake state ends, the working group in the air outlet state of the other two working groups continues to maintain the air outlet state, and the working group in the purging state switches to the air intake state.

[0024] Similarly, for any working group, when it is halfway through its exhaust state (half the time), the working states of the other two working groups are switched (from intake state to purging state, or from purging state to intake state). When its exhaust state ends, the working group in the intake state of the other two working groups continues to maintain the intake state, and the working group in the purging state switches to the exhaust state.

[0025] The beneficial effects of this invention are as follows: Since the gas collection and heat storage chambers of the RTO can be divided into four groups, three groups are used for normal operation, sequentially implementing air intake, exhaust, and purging, while the remaining group is on standby or can be used for back-burning as needed. This online back-burning does not affect the normal treatment of waste gas by the RTO, does not change the normal treatment method of the RTO, and does not require production line shutdown, thus avoiding the hindrance of back-burning to waste gas treatment or treatment effect. Since the number of gas collection and heat storage chambers is 3n+m, where n and m are both positive integers and m ≤ n, the number of gas collection and heat storage chambers in the three groups used for normal operation can be equal. The number of gas-collecting regenerators in the standby / reverse combustion group is no greater than that in the normal operation group. This minimizes the time the gas-collecting regenerators are in standby mode while still meeting reverse combustion requirements, thus avoiding waste. Since the high-temperature gas from the combustion chamber enters directly from the top of the gas-collecting regenerator requiring reverse combustion, there is no need for pipelines and valves to transport the high-temperature gas from the combustion chamber used for reverse combustion. This saves on equipment costs and maintenance expenses incurred for reverse combustion. Furthermore, the outlet valve and purge valve of the reverse combustion gas-collecting regenerator (the one implementing reverse combustion) can be used for control. Based on actual needs, the high-temperature gas from the combustion chamber is introduced into the reverse combustion gas collection and regenerator chamber by opening the exhaust valve (with the purge valve closed) to raise the temperature. Meanwhile, relatively low-temperature purge air is sent into the reverse combustion gas collection and regenerator chamber by opening the purge valve (with the exhaust valve closed), controlling the temperature of the regenerator layer and its lower part within a suitable range. This achieves effective reverse combustion and avoids safety hazards caused by excessively high temperatures in the gas collection and regenerator chamber. Because a pre-installed gas-to-gas heat exchanger is used, steam or RTO exhaust gas is used as the exothermic medium to preheat the exhaust gas. This not only increases the exhaust gas temperature and reduces the heating load on the gas collection and regenerator chamber but also helps to avoid… This design avoids temperature shocks to the heat storage material caused by relatively low exhaust gas temperatures, helping to extend the material's lifespan and reduce blockage in the gas collection heat storage chamber. Since both the inlet and outlet branch pipes are connected to purge branch pipes, with the connections located on the gas collection heat storage chamber side of the inlet and outlet valves respectively, backflushing / purging is possible after both inlet and outlet operations. This ensures that the gas in the inlet branch pipe near the gas collection heat storage chamber on the inlet valve side and the outlet branch pipe near the gas collection heat storage chamber on the outlet valve side are thoroughly purged, preventing these pipes from hindering the purification effect. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the regenerative thermal incineration system involved in this invention. Detailed Implementation

[0027] See Figure 1The regenerative thermal oxidizer system of the present invention has an online reverse combustion function and can operate using any of the control methods / operating methods disclosed in the present invention. It includes a regenerative thermal oxidizer 20, which is provided with a plurality of gas collection and heat storage chambers 22. The number of gas collection and heat storage chambers is 3N+M, where N and M are both positive integers. For example, a simple and practical implementation is to set up four gas collection and heat storage chambers (four-chamber structure), with three of the chambers performing the working cycle (air intake, air exhaust, purging), and one chamber in reserve. The reserve gas collection and heat storage chamber can be used for online reverse combustion as needed.

[0028] The regenerative thermal oxidizer can adopt existing technology and is equipped with an inlet pipe 30, an outlet pipe 40, and a purge pipe 50. The inlet pipe of the regenerative thermal oxidizer is connected to the corresponding gas-collecting heat storage chamber from the bottom through several inlet branch pipes 31. Each inlet branch pipe is equipped with its own inlet valve. The outlet pipe of the regenerative thermal oxidizer is connected to the corresponding gas-collecting heat storage chamber from the bottom through several outlet branch pipes 41. Each outlet branch pipe is equipped with its own outlet valve. The purge pipe of the regenerative thermal oxidizer is connected to the corresponding gas-collecting heat storage chamber from the bottom through several purge branch pipes 51. Each purge branch pipe is equipped with its own purge valve. Through the coordinated control of the inlet valve, outlet valve, and purge valve, under normal working conditions, N gas-collecting heat storage chambers can be used for inlet, N gas-collecting heat storage chambers for outlet, N gas-collecting heat storage chambers for purge, and M gas-collecting heat storage chambers for standby. According to the process flow, the intake, exhaust, and purging are sequentially switched among the 3N gas collection and heat storage chambers, with the standby gas collection and heat storage chambers rotating sequentially among all 3N+M gas collection and heat storage chambers. When online backfire is required, the standby gas collection and heat storage chambers are subjected to online backfire.

[0029] Backfiring is only performed when the gas collection and heat storage chamber is in standby mode. For standby gas collection and heat storage chambers that do not require backfiring, backfiring is not performed. If, for some reason, one or more gas collection and heat storage chambers in the working cycle (inlet, outlet, and purging) need backfiring, they will be removed from the working cycle during the next state switch in the working cycle, enter standby mode, and undergo backfiring. One or more standby gas collection and heat storage chambers that should have entered the working cycle in the subsequent rotation according to the original order will be switched into the working cycle to replace the gas collection and heat storage chambers that were removed from the working cycle for backfiring.

[0030] The specific method for implementing reverse combustion in the gas-collecting regenerator chamber is as follows: The inlet valve is always kept closed. Initially, the outlet valve of the gas-collecting regenerator chamber is opened, and the purge valve is closed. High-temperature gas from the combustion chamber flows in from the top and out from the bottom of the chamber, then enters the outlet pipe via the outlet branch pipe. The heat storage layer absorbs the heat energy of the high-temperature gas, causing the temperature to rise until the required reverse combustion temperature is reached, thus entering the reverse combustion state. During the reverse combustion process, when a temperature increase is needed, the outlet valve is opened and the purge valve is closed, allowing high-temperature gas to flow through the gas-collecting regenerator chamber, thus raising the temperature. When a temperature decrease is needed, the purge valve is opened and the outlet valve is closed, allowing purge gas to flow through the gas-collecting regenerator chamber, thus lowering the temperature. The opening and closing sequence of the outlet valve and the purge valve can be set, and their opening and closing can be alternated to maintain the required reverse combustion state. The opening and closing sequence of the outlet valve and the purge valve can be obtained based on experiments and / or theoretical calculations. The backfire time (duration) is set according to actual needs, and the standby state duration should meet the backfire time requirements. Based on this requirement, the standby state duration can be the same as or different from the state switching duration in the working cycle. When they are different, it can be an integer multiple of the state switching duration in the working cycle to ensure that the standby rotation (the rotation of the gas storage chamber between standby and working cycles) is coordinated with the state switching in the working cycle.

[0031] For simplicity, the purge branch pipe can be directly connected to the corresponding gas collection and heat storage chamber from the bottom. The purge gas flows directly into the gas collection chamber without passing through the inlet branch pipe and outlet branch pipe (and their gas distribution / collection device 23, if provided). This blows the gas in the gas collection chamber and the heat storage chamber located above the gas collection chamber into the combustion chamber, so as to avoid the exhaust gas in the gas collection and heat storage chamber from mixing with the exhaust gas, which would reduce the purification effect or affect the stability of the device.

[0032] In a preferred embodiment, the purge branch pipe can be divided into two paths. Two purge connecting pipes leading out from the purge branch pipe are respectively connected to the inlet branch pipe on the gas collection and heat storage chamber side of the gas collection and heat storage chamber located at the inlet valve and the outlet branch pipe on the gas collection and heat storage chamber side of the outlet valve. The two purge connecting pipes are indirectly connected to the gas collection and heat storage chamber via the inlet branch pipe and the outlet branch pipe (and their gas distribution / collection devices, if provided). During the corresponding purge, the exhaust gas in the inlet branch pipe and the outlet branch pipe (and their gas distribution / collection devices, if provided) on the gas collection and heat storage chamber side is blown into the combustion chamber 21 together with the exhaust gas in the gas collection and heat storage chamber, further ensuring the purification effect and the stability of the device.

[0033] The connection points of the purging connection pipe on the inlet and outlet branch pipes should be as close as possible to the inlet and outlet valves, respectively; the closer the connection, the cleaner the purging. As a preferred embodiment, a tee (tee connecting fitting) can be installed on the gas collection and heat storage chamber side of the inlet valve (or outlet valve). The purging connection pipe is connected to the corresponding purging connection pipe through the bypass port of the tee, and the straight port of the tee is connected to the gas collection and heat storage chamber side interface of the inlet valve (or outlet branch pipe) and the gas collection and heat storage chamber side inlet pipe (or gas collection and heat storage chamber side outlet pipe), respectively. Furthermore, the tee is preferably a Y-type tee, connecting the purging connection pipe to the downward-sloping port, so that the inlet direction of the purging airflow is upward-sloping. This not only helps reduce resistance but also, through the entrainment effect of the purging airflow, makes the purging more thorough.

[0034] When the purge branch pipes are connected to their respective gas collection and heat storage chambers via two purge connection pipes, which are respectively connected to the inlet branch pipe on the gas collection and heat storage chamber side of the inlet valve and the outlet branch pipe on the gas collection and heat storage chamber side of the outlet valve, the purge valves can be installed on the purge branch pipes, or two purge valves can be used, which are respectively installed on the two purge connection pipes. In this case, the purge valves on the corresponding purge connection pipes can be opened during purge after inlet and purge after outlet.

[0035] Thermal storage ceramics can be used as the thermal storage material in the thermal storage chamber and arranged into a thermal storage layer. The gaps between the thermal storage ceramics are used as airflow channels.

[0036] The burner or injector 28 of the RTO can be set according to existing technology, and the space below the combustion chamber can be divided into several gas collection and heat storage chambers by using a partition 26.

[0037] The air intake pipe is equipped with a front-mounted main fan 35, whose main function is to transport the treated waste gas (e.g., the gas from the front workshop) to the RTO.

[0038] A flame arrester 39 is installed on the air intake pipe, located between the main front fan and the air intake branch pipe. The temperature inside the air intake pipe on the front side (air intake side) of the flame arrester is lower, while the temperature on the rear side of the flame arrester is higher, and the RTO combustion chamber is in an open flame state. The flame arrester is mainly installed to prevent open flames from entering the front delivery system and causing a combustion and explosion accident. The flame arrester has a narrow gap. When the flame passes through the narrow gap, the heat loss suddenly increases, causing combustion to stop and the flame to extinguish.

[0039] A steam heat exchanger 38 is connected to the air inlet pipe. This steam heat exchanger uses steam as the heat transfer medium and is located on the air inlet side of the main blower. It primarily uses steam heat exchange to increase the temperature of the incoming air (the waste gas to be treated, such as industrial tail gas) and prevent the condensation and accumulation of organic matter at lower temperatures. Depending on actual needs, other types of heaters can be used to replace the steam heat exchanger.

[0040] Typically, a steam heat exchanger can be used to raise the temperature of the incoming air to 80-100℃.

[0041] The main intake shut-off valve 36 is connected to the intake pipe. The main intake shut-off valve is located on the intake side of the steam heat exchanger. The intake side of the main intake shut-off valve is used to connect the pipeline of the gas to be treated (or waste gas, such as industrial tail gas). It is mainly used to isolate and shut off the gas from the upstream workshop (or other waste gas sources) of this system.

[0042] The purge pipe is connected to the purge fan 55 to generate purge air (purge airflow) to purge the gas collection and heat storage chamber. The main function of the purge after the intake is to transport the exhaust gas that was retained in the gas collection chamber and heat storage chamber during the intake of the previous cycle to the combustion chamber through the purge air, so that it can be completely oxidized at high temperature, thereby ensuring that the gas discharged in the next cycle has been oxidized at high temperature.

[0043] The combustion chamber of the regenerative thermal oxidizer can be connected to a high-temperature hot bypass pipe 61. The high-temperature hot bypass pipe is equipped with a bypass valve. Both the high-temperature hot bypass pipe and the outlet pipe of the regenerative thermal oxidizer are connected to a high-temperature mixing device (e.g., a high-temperature mixer) 60. The outlet of the high-temperature mixing device is connected to the inlet of the quench tower 70 via a gas delivery pipe 66. Because a high-temperature bypass and a corresponding high-temperature mixing chamber are provided for the combustion chamber, a portion of the combustion chamber's outlet gas can be directly drawn from the combustion chamber as needed and mixed with the outlet gas drawn from the corresponding gas-collecting regenerator in the high-temperature mixing chamber, serving as the RTO outlet gas. This reduces the high-temperature airflow through the gas-collecting regenerator when necessary, avoiding safety hazards caused by excessively high temperatures in the gas-collecting regenerator.

[0044] The quench tower can be a forward-flow spray tower, or other types of quench towers depending on actual needs. The air inlet of the forward-flow quench tower is located at the top of the tower, the spray pipe 72 of the spray device is located in the upper part of the tower, the lower part of the tower is a sedimentation zone, a drain pipe is located at the bottom of the tower, and an air outlet 79 and a water outlet are located on the side of the tower. The water outlet connects to the sedimentation zone 74, and the air outlet is located above the sedimentation zone and connected to the chimney through an exhaust pipe. Because the quench tower is used for the rapid cooling of the RTO exhaust gas, part or all of the RTO exhaust gas can be used as the heat release medium of the gas-to-gas heat exchanger. After heat release, the quench tower can be used for cooling as needed, thus effectively utilizing the exhaust gas heat energy.

[0045] The outlet of the quench tower is connected to the inlet pipe of the spray device through a circulation pipe, and a circulation pump 77 is installed on the circulation pipe.

[0046] The quench tower is equipped with a water supply pipe / water replenishment pipe. The inner end of the water supply pipe / water replenishment pipe of the quench tower is connected to the water inlet pipe of the spray device, and the outer end is connected to an external industrial water pipeline or fire water pipeline, using the external industrial water pipeline or fire water pipeline as the water supply / replenishment source for the spray device.

[0047] The quench tower may be equipped with a packing layer 73, which is located below the corresponding spray pipe to improve the cooling speed and enhance the cooling effect.

[0048] The quench tower may be equipped with multiple layers of spray pipes and packing layers, for example, two layers.

[0049] Depending on actual needs, a gas-liquid separation device can be installed between the quench tower and the chimney to further separate the water entrained in the gas flow. If the quench tower itself has a good gas-liquid separation effect or in other cleaning processes where gas-liquid separation is not required, a gas-liquid separation device may not be installed.

[0050] The gas-liquid separation device can be any suitable existing technology and connected in series in the exhaust pipe.

[0051] The control method of this invention will be specifically explained below using a four-chamber RTO (with four gas collection and heat storage chambers) as an example:

[0052] Normal operating conditions: After the exhaust gas is introduced into the intake pipe through the main intake shut-off valve, it is first heated to 80-100℃ by the steam heat exchanger, and then transported by the front main fan. After passing through the flame arrester, it enters the gas collection and heat storage chamber in the air intake state through the corresponding intake branch pipe according to the opening and closing status of each valve. In the gas collection and heat storage chamber, the gas is first evenly distributed in the gas collection chamber by the airflow distributor, and then preheated by the heat storage ceramic layer of the heat storage chamber. Then it enters the combustion chamber for thermal oxidation (or incineration). The oxidized gas enters the heat storage layer of the other gas collection and heat storage chamber from above, releases heat to the heat storage layer, causes the heat storage material to absorb heat and rise in temperature, and then flows out through the gas collection chamber, and flows into the exhaust pipe through the exhaust branch pipe and exhaust valve.

[0053] Each chamber of the RTO (Regenerative Thermal Oxidizer) can be divided into four states according to the switching cycle: intake, exhaust, purging, and standby. There is also a reverse-firing state, which, since it is implemented during the standby phase, can be considered a special form of standby. In the intake state, the intake valve of the chamber is open; in the exhaust state, the exhaust valve is open; in the purging state, the purging valve is open; in the standby state (when not reverse-firing), the intake, exhaust, and purging valves of the chamber are all closed; in the reverse-firing state, the exhaust and purging valves of the chamber operate according to the temperature of the lower ceramic layer of the regenerative chamber to maintain the reverse-firing temperature.

[0054] From a control perspective or from a functional perspective, each room is of equal status.

[0055] During normal operation, the four chambers cycle through four states: air intake, air exhaust, purging, and standby. Table 1 shows a preferred specific switching cycle / sequence.

[0056] When reverse combustion is performed, the chamber undergoing reverse combustion is in reverse combustion mode, while the other three chambers switch cyclically according to three states: air intake, air exhaust, and purging. Table 2 shows a preferred specific switching cycle / sequence (taking reverse combustion of chamber #4 as an example).

[0057] Table 1. Normal operating cycle of RTO four chambers

[0058]

[0059] Table 2: Cycle for normal bed switching when #4 room undergoes reverse heating.

[0060]

[0061] A flow regulating valve can be used as both the outlet valve and the purge valve. During the back-burning process, the appropriate outlet flow rate and purge flow rate can be set according to the actual temperature change requirements to achieve precise control of the heat storage layer temperature while also taking into account the control speed.

[0062] Typically, appropriate thermocouples can be set up to detect the temperature inside the RTO, such as the temperature of the lower / bottom part of the heat storage layer. The temperature of this part can be used as a temperature indicator for backfire, or the so-called backfire temperature is the temperature of the lower or bottom part of the heat storage layer.

[0063] Typically, pressure testing instruments (e.g., pressure transmitters) can be used to detect the internal pressure of the RTO. The pressure difference between the upper and lower parts of the heat storage layer in the air intake or exhaust state is used as the basis for judging whether the heat storage layer needs to be reverse-burned. When the pressure difference increases, it indicates that the resistance of the heat storage layer increases, or that the degree of blockage is enhanced. When the pressure difference reaches a certain level, online reverse-burning is implemented in the corresponding gas collection heat storage chamber.

[0064] Based on ease of operation and equipment simplification, the pressure difference between the RTO inlet and outlet (the pressure difference between the inlet and outlet pipes adjacent to the RTO) can be used as the criterion for back-burning. When this pressure difference exceeds a certain limit, each gas collection and heat storage chamber is sequentially back-burned online. For example, all gas collection and heat storage chambers that subsequently enter standby mode can be back-burned online once.

[0065] Online back-burning of each gas-collecting heat storage chamber can also be performed periodically. Alternatively, a combination of online back-burning based on pressure difference detection and timed online back-burning can be used, with online back-burning implemented once any back-burning condition is met.

[0066] Unless otherwise specified or further limited to one preferred or optional technical means being another, the preferred and optional technical means disclosed in this invention can be arbitrarily combined to form several different technical solutions.

Claims

1. A regenerative thermal oxidizer with online reverse combustion function, comprising a regenerative thermal oxidizer, wherein the regenerative thermal oxidizer is provided with a plurality of gas collecting and regenerating chambers, characterized in that... The number of gas-collecting heat storage chambers is 3N+M, where N and M are both positive integers. Under normal operating conditions, the gas-collecting heat storage chambers are divided into three working groups and one standby group. Each working group has N gas-collecting heat storage chambers, and the standby group has M gas-collecting heat storage chambers. The regenerative thermal oxidizer is equipped with an inlet pipe, an outlet pipe, and a purge pipe. The inlet pipe of the regenerative thermal oxidizer connects to the corresponding gas-collecting heat storage chamber from the bottom through several inlet branch pipes, each with its own inlet valve. The outlet pipe of the regenerative thermal oxidizer connects to the corresponding gas-collecting heat storage chamber from the bottom through several outlet branch pipes, each with its own outlet valve. The purge pipe of the regenerative thermal oxidizer connects to each gas-collecting heat storage chamber through several purge branch pipes, each with its own purge valve. The purge branch pipes are connected to the corresponding gas-collecting heat storage chamber located at the inlet valve through two purge connection pipes. On the inlet branch pipe on the side and on the outlet branch pipe on the side of the gas collecting and heat storage chamber located at the outlet valve, online back-burning is implemented for the gas collecting and heat storage chambers in the standby group that require back-burning. The temperature of the heat storage layer of the gas collecting and heat storage chamber in online back-burning is adjusted by regulating the outlet valve and the purge valve of the gas collecting and heat storage chamber in online back-burning to reach the required temperature. During the entire back-burning process, the inlet valve of the gas collecting and heat storage chamber in online back-burning is closed. At the beginning stage of back-burning, the outlet valve of the gas collecting and heat storage chamber in online back-burning is opened, and the purge valve is closed. The purge valve allows the high-temperature airflow from the combustion chamber to pass through the corresponding heat storage chamber, causing the heat storage material in the corresponding heat storage chamber to absorb heat and rise in temperature until the reverse combustion temperature is reached. The reverse combustion temperature is maintained for a certain period of time until the reverse combustion purpose is achieved. The method of maintaining the reverse combustion temperature is as follows: when it is necessary to raise the temperature, the outlet valve is opened and the purge valve is closed, allowing the high-temperature airflow from the combustion chamber to pass through the corresponding heat storage chamber; when it is necessary to lower the temperature, the outlet valve is closed and the purge valve is opened, allowing external purge air to pass through the corresponding heat storage chamber.

2. The regenerative thermal ignition system with online reverse combustion function as described in claim 1, characterized in that... The air intake pipe is equipped with a front-mounted main fan.

3. The regenerative thermal ignition system with online reverse combustion function as described in claim 2, characterized in that... A flame arrester is installed on the air intake pipe, and the flame arrester is located between the front main fan and the air intake branch pipe.

4. The regenerative thermal ignition system with online reverse combustion function as described in claim 3, characterized in that... A steam heat exchanger is connected to the air inlet pipe. The steam heat exchanger uses steam as the heat release medium and is located on the air inlet side of the front main fan.

5. The regenerative thermal ignition system with online reverse combustion function as described in claim 4, characterized in that... A main intake shut-off valve is connected to the intake pipe. The main intake shut-off valve is located on the intake side of the steam heat exchanger. The intake side of the main intake shut-off valve is used to connect to the gas pipeline to be treated.

6. The control method of a regenerative thermal ignition system with online reverse combustion function, characterized in that... The regenerative thermal oxidizer with online reverse combustion function includes a regenerative thermal oxidizer. The regenerative thermal oxidizer has 3N+M gas collection and heat storage chambers, where N and M are both positive integers. Under normal operating conditions, the gas collection and heat storage chambers are divided into three working groups and one standby group. Each working group has N gas collection and heat storage chambers. When N is greater than 1, the working states of all gas collection and heat storage chambers within the same working group are consistent. The standby group has M gas collection and heat storage chambers. The regenerative thermal oxidizer has an inlet pipe, an outlet pipe, and a purge pipe. The inlet pipe of the regenerative thermal oxidizer connects to... Several inlet branch pipes connect to the bottom of each gas collecting and heat storage chamber, and each inlet branch pipe is equipped with its own inlet valve. The outlet pipe of the regenerative thermal oxidizer connects to the bottom of each gas collecting and heat storage chamber via several outlet branch pipes, and each outlet branch pipe is equipped with its own outlet valve. The purge pipe of the regenerative thermal oxidizer connects to each gas collecting and heat storage chamber via several purge branch pipes, and each purge branch pipe is equipped with its own purge valve. The purge branch pipes are connected to the corresponding gas collecting and heat storage chamber via two purge connecting pipes located at the inlet valve. On the inlet branch pipe on the side of the gas-collecting heat storage chamber and on the outlet branch pipe on the side of the gas-collecting heat storage chamber located at the outlet valve, each gas-collecting heat storage chamber rotates sequentially between the working group and the standby group. Gas-collecting heat storage chambers in the standby group that require back-burning are back-burned online, while those in the standby group that do not require back-burning remain stopped. The temperature of the heat storage layer in the online back-burning gas-collecting heat storage chamber is adjusted by regulating the outlet valve and purge valve to reach and maintain the required back-burning temperature. During the entire back-burning process, the inlet valve of the back-burning gas-collecting heat storage chamber is closed. In the initial stage of reverse combustion, the outlet valve of the online reverse combustion gas collection and heat storage chamber is opened, and the purge valve is closed, allowing the high-temperature airflow from the combustion chamber to pass through the corresponding gas collection and heat storage chamber. This causes the heat storage material in the corresponding gas collection and heat storage chamber to absorb heat and rise in temperature until the reverse combustion temperature is reached. The reverse combustion temperature is maintained for a certain period of time until the reverse combustion purpose is achieved. The method for maintaining the reverse combustion temperature is as follows: when it is necessary to raise the temperature, the outlet valve is opened and the purge valve is closed, allowing the high-temperature airflow from the combustion chamber to pass through the corresponding gas collection and heat storage chamber. When it is necessary to lower the temperature, the outlet valve is closed and the purge valve is opened, allowing external purge air to pass through the corresponding gas collection and heat storage chamber.

7. The control method of the regenerative thermal ignition system with online reverse combustion function as described in claim 6, characterized in that... At the end of the back-burning stage, close the gas outlet valve and open the purge valve to allow the external purge gas to pass through the corresponding gas collection and heat storage chamber, causing the heat storage material in the corresponding gas collection and heat storage chamber to release heat and heat up until the standby temperature is reached.

8. The control method of the regenerative thermal ignition system with online reverse combustion function as described in claim 6, characterized in that... For any working group, after the intake state ends and the exhaust state ends, it enters the purging state. The duration of the purging state is half the duration of the intake state. The durations of the intake state and the exhaust state are the same. For any working group, when its intake state is halfway through, the working states of the other two working groups are switched. When its intake state ends, the working group in the exhaust state of the other two working groups continues to maintain the exhaust state, and the working group in the purging state switches to the intake state.

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