A waste gas heating system based on a heat generating device and a control method thereof

Abstract

The present invention is applicable to the field of waste gas heating devices, and provides a waste gas heating system based on a heat generating device and a control method thereof, including an instrument and electrical control system and a heating module; the interior of the heating module includes a distribution area, a heat storage area and a heat treatment chamber; different sectors are arranged in the heat storage area; each of the sectors is installed with a ceramic body with heating and heat storage functions; the distribution area includes an air inlet area, a discharge area and a lifting valve damper mechanical structure separated by a partition, and the lifting valve damper mechanical structure includes a plurality of waste gas lifting valves, and the waste gas lifting valve can control the conduction relationship between the sector and the air inlet area, and between the sector and the discharge area. In this way, the device can monitor the real-time temperature of each partition, the valve operation status, and the system pressure, temperature and other parameters in real time through the instrument and electrical control system, so as to accurately judge the working status of each partition, make decisions on function switching, and ensure the stability and reliability of the entire system.

Description

Technical Field

[0001] The present invention is applicable to the field of waste gas heating devices, and provides a waste gas heating system based on a heat generating device and a control method thereof. Background Art

[0002] At present, the exhaust gas heating system based on the heat generating device includes heating systems such as the RTO system. The RTO (regenerative thermal oxidizer) is a cylindrical regenerative thermal oxidation reactor. It consists of a shell, ceramic fiber insulation cotton, a regenerative body, a lifting valve, a purge valve, a burner, an electronic control system, etc. The principle is that after the exhaust gas stays in the furnace for a sufficient time (>1.0s), the organic matter is converted into harmless carbon dioxide and water through a high-temperature oxidation reaction, thereby achieving the purpose of treating pollutants. The organic exhaust gas is heated to above 800°C, so that the volatile organic compounds (VOCs, Volatile Organic Compounds) in the exhaust gas are oxidized and decomposed into carbon dioxide and water in the combustion chamber. The high-temperature gas generated by oxidation flows through a special ceramic regenerative body, causing the ceramic body to heat up and "storage heat". The next process is that the exhaust gas passes through the ceramic that has "stored heat" and transfers the heat of the ceramic to the exhaust gas. The organic exhaust gas uses the ceramic regenerative body as a heat exchanger carrier to repeatedly exchange heat, thereby saving fuel consumption for exhaust gas heating and reducing operating costs. Under conditions of medium and high concentrations, the heating system can export waste heat to the outside and utilize it in the form of thermal oil, steam, hot air, hot water, etc., thereby achieving additional economic benefits while meeting environmental standards.

[0003] In the heating system of the prior art, the ceramic bed layer which plays the role of heat storage needs to continuously carry out the cycle of absorbing and releasing heat. According to the different ways of realizing the cycle, it can be divided into two types: multi-bed tower type and rotary valve type.

[0004] The heat storage bodies of multiple towers (usually 3 to 5 towers) are used alternately and cyclically. The gas channel is changed by switching valves, and the gas enters different heat storage body beds periodically to achieve the process of cold and hot cycle. The lifting valve has good sealing performance, long life / easy maintenance, and high processing efficiency. The air volume of a single unit can be designed to be >100,000m³ / h. Its main advantage is the lifting valve; its disadvantage is that it occupies a large area, and some projects are limited by on-site installation conditions.

[0005] The rotary RTO mainly introduces gas into different heat storage areas periodically through the rotary valve components, realizing the cycle process of heat storage body absorbing and releasing heat over time. The rotary valve is an integrated single valve. Because the rotary valve rotates continuously, the air tightness is affected by temperature or dust. The drive of the rotary valve is a variable frequency drive, so the speed is adjusted according to the real-time working conditions to deal with various working conditions. The air volume handled by a single rotary RTO should be less than 80,000 m³ / h. Because the larger the air volume, the larger the diameter of the rotary valve body, the unstable operation and easy problems, and difficult maintenance.

[0006] At present, there have been cylinder-type lifting valve groups RTO in the market in the early stage: "multi-claw squid-type structure", but they are all controlled by butterfly valves. The disadvantage is that the butterfly valve is affected by the sealing (the sealing is not high) and the diameter of the butterfly valve cannot be too large / the air volume is small, otherwise it is easy to leak. In this way, it is difficult to increase the air volume handled by its RTO. Summary of the invention

[0007] In view of the above-mentioned defects, the purpose of the present invention is to provide an exhaust gas heating system based on a heat generating device and a control method thereof, in order to solve the problems raised in the background technology. The exhaust gas heating system based on the heat generating device includes an instrumentation control system and a heating module; the interior of the heating module includes a distribution area, a heat storage area and a heat treatment chamber; different sectors are arranged in the heat storage area; each of the sectors is equipped with a ceramic body with heating and heat storage functions; the distribution area includes an air inlet area, an exhaust area and a lifting valve damper mechanical structure separated by a partition, and the lifting valve damper mechanical structure includes a plurality of exhaust gas lifting valves, and the exhaust gas lifting valve can control the conduction relationship between the sector and the air inlet area, and between the sector and the exhaust area.

[0008] Furthermore, thermocouples are installed in the heat treatment chamber and in each sector, and the thermocouples are electrically connected to an instrument electrical control system.

[0009] Furthermore, the heat storage area is divided into 11 sectors, and each sector corresponds to 2 lifting valves and 1 purge valve.

[0010] Furthermore, the heating module includes an outer shell; the interior of the outer shell is provided with a distribution area, a heat storage chamber and a heat treatment chamber in sequence from bottom to top; the heat storage chamber and the heat treatment chamber are connected, and a partition plate is provided in the heat storage chamber to evenly distribute the heat storage chamber space into 11 sectors; a partition is provided between the distribution area and the heat storage chamber, and a plurality of valve ports are provided on the partition; the lifting valve includes an exhaust gas outlet lifting valve and an exhaust gas inlet lifting valve, and the purge valve is a purge lifting valve, and each of the sectors is provided with three valve ports corresponding to the exhaust gas inlet lifting valve, the exhaust gas outlet lifting valve and the purge lifting valve at the bottom; two annular partitions are provided in the distribution area, and the two annular partitions with different inner diameters divide the distribution area into an exhaust gas outlet channel, an exhaust gas inlet channel and a purge inlet channel; the outer shell is provided with an exhaust gas inlet connected to the exhaust gas inlet channel, an exhaust gas outlet connected to the exhaust gas outlet channel, and a purge interface connected to the purge inlet channel;

[0011] The valve port corresponding to the exhaust gas inlet lift valve also corresponds to the exhaust gas inlet passage;

[0012] The valve port corresponding to the exhaust gas outlet lift valve also corresponds to the exhaust gas outlet passage;

[0013] The valve port corresponding to the purge lift valve also corresponds to the purge inlet passage.

[0014] Furthermore, the outer shell is provided with a first heat treatment chamber interface, a second heat treatment chamber interface, a high temperature release port and an explosion relief port connected to the heat treatment chamber.

[0015] Furthermore, the outer shell and the two annular partitions are provided with lift valve inspection doors.

[0016] A control method for an exhaust gas heating system based on a heat generating device can control the opening and closing of a plurality of exhaust gas outlet lift valves, exhaust gas inlet lift valves and purge lift valves on a heating module in the exhaust gas heating system based on a heat generating device through an instrument and electrical control system to switch and control the gas flow in each sector in a heat storage area; specifically, the following steps are included:

[0017] S1. System initialization: Start the instrument and electrical control system and initialize the system, including loading the PLC program in the system, starting the monitoring host, and initializing the human-machine interface; check the status of each lift valve and purge valve; calibrate the thermocouple and pressure sensor;

[0018] S2. The system allocates five sectors as air intake sectors, one sector as purge sector, and the remaining five sectors as air outlet sectors, and controls the heat source of the air intake sector to actively preheat the ceramic body therein so that the ceramic body reaches the specified temperature;

[0019] S3. When the ceramic body in the air intake partition reaches the specified temperature, the instrument and electrical control system opens the exhaust gas inlet lift valve corresponding to the air intake partition, and the exhaust gas exchanges heat with the heat storage body in the air intake partition and enters the heat treatment chamber after preheating;

[0020] S4. The purified exhaust gas exchanges heat with the heat storage body in the outlet partition. At this time, the hot purifier heats the heat storage body in the outlet partition and stores the heat energy in the heat storage body. During the entire purification process, the instrument and electrical control system monitors and records the real-time temperature of each partition, and records the outlet partition where the heat storage body that has reached the specified temperature is located as the preparatory partition.

[0021] S5. The instrument and electrical control system performs balanced control on the temperature of the corresponding partitions according to the temperature deviation value of each partition and the judgment of the preparatory partition. The specific control method is as follows:

[0022] If the working temperature of the same functional partition is different, and if there is no preparatory partition, the instrument and electrical control system will adjust the corresponding partition with the deviation value to control the air volume or heat source, so as to balance the temperature. If there is a preparatory partition, the partition function will be switched by switching the corresponding partition with the deviation value.

[0023] Furthermore, the step S3 is specifically as follows:

[0024] S3.1. The temperature sensor in the heat treatment chamber monitors the temperature in real time and feeds the data back to the instrumentation and electrical control system;

[0025] S3.2. PLC adjusts the heating capacity of the heat processor according to the temperature data to keep the temperature of the heat treatment chamber within the range of 780℃-850℃;

[0026] S3.3. If the temperature exceeds the upper limit, the system will automatically open the over-temperature discharge valve; if it exceeds the upper limit, the system will alarm and shut down.

[0027] Furthermore, the step is also included: S6. The operating status of each valve and the system's pressure, temperature and other parameters are monitored in real time through the instrument and electrical control system. If an abnormal situation is found, the system immediately sends out an alarm signal. According to the alarm type, the system automatically takes corresponding protection measures and prompts the operator to handle it.

[0028] Therefore, the present invention optimizes and manages the gas flow and heat exchange inside the heating module through the instrument and electrical control system. First, when the system is initialized, the instrument and electrical control system is started, the PLC program is loaded, the monitoring host and the human-machine interface are started, the status of all valves is checked, and the thermocouples and pressure sensors are calibrated. When the system is running, the sectors in the heat storage area are divided into air intake partitions, purge partitions, and air outlet partitions. The ceramic body of the air intake partition is actively preheated by the heat source. After reaching the specified temperature, the instrument and electrical control system will open the corresponding exhaust gas inlet lift valve, allowing the exhaust gas to enter the air intake partition and exchange heat with the heat storage body. The preheated exhaust gas enters the heat treatment chamber for high-temperature oxidation reaction. At the same time, the purified exhaust gas exchanges heat with the heat storage body in the air outlet partition, and the hot purified exhaust gas stores heat energy in the heat storage body. The instrument and electrical control system will monitor and record the real-time temperature of each partition, and record the air outlet partition where the heat storage body that has reached the specified temperature is located as a preparatory partition for subsequent temperature balance control. In terms of temperature balance control, if there is a difference in the working temperature between the same functional partitions and there is no preparatory partition, the instrument and electrical control system will balance the temperature by adjusting the corresponding partition with the deviation value to control the air volume or heat source. If there is a preparatory partition, the partition function is switched by switching the corresponding partition with the deviation value to achieve more efficient thermal energy utilization and exhaust gas treatment. In addition, the system also has real-time monitoring and alarm functions, which can monitor the operating status of each valve and the system's pressure, temperature and other parameters in real time. Once an abnormal situation is found, the system will immediately issue an alarm signal and automatically take corresponding protection measures according to the alarm type to prompt the operator to handle it.

[0029] Beneficial effects:

[0030] 1. Improve processing efficiency and stability: By optimizing the internal structure of the heating module and improving the sealing of the valve, the patented system can process exhaust gas more efficiently while ensuring the stable operation of the system. The instrument and electrical control system can intelligently select the preparatory partition, and finely control and intelligently manage the exhaust gas flow and heat exchange process;

[0031] 2. The instrument and electrical control system monitors and records the real-time temperature of each partition, the operating status of each valve, and the system's pressure, temperature and other parameters in real time, so as to accurately judge the working status of each partition and make decisions on function switching accordingly, thus ensuring the stability and reliability of the entire system;

[0032] 3. Energy saving and consumption reduction: Through the heat storage and heat release process of the ceramic body, the system can make full use of thermal energy and reduce fuel consumption and operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of the heating module;

[0034] Figure 2 To omit the top view of the heating module behind the inspection stairs;

[0035] Figure 3 Side view of the heating module after omitting the access stairs;

[0036] Figure 4 for Figure 2 AA direction structure view;

[0037] Figure 5 for Figure 2 BB direction structural view;

[0038] Figure 6 for Figure 3 CC direction structural view;

[0039] Figure 7 The diagram is a schematic diagram of the distribution of the lifting valve and the purge valve on the partition;

[0040] Figure 8 A cross-sectional view of the heating module after the access stairs is omitted;

[0041] Fig. 9 It is a schematic diagram of the internal partition of the rotary valve RTO system;

[0042] In the figure: 01-waste gas inlet channel; 02-waste gas outlet channel; 03-purge inlet channel; 1-heat storage chamber; 10-outer shell; 101-partition plate; 102-annular partition plate; 11-waste gas inlet; 12-waste gas outlet; 13-purge interface; 14-lift valve inspection door; 2-heat treatment chamber; 21-first heat treatment chamber interface; 22-second heat treatment chamber interface; 23-high temperature release port; 24-explosion vent; 31-waste gas inlet lift valve; 32-waste gas outlet lift valve; 33-purge lift valve; 4-inspection stairs. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0044] It should be noted that, in the description of the present invention, unless otherwise specified, "plurality" means two or more than two; the orientations or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0045] Meanwhile, in the description of the present invention, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] The exhaust gas heating system based on the heat generating device of the present technical solution utilizes a combination of thermal oxidation and heat recovery to efficiently remove pollutants, while also maximizing savings in operating costs.

[0048] Oxidation is a destructive waste gas treatment method that can adapt to different flow rates and concentrations of pollutants. The principle of the thermal oxidation process is to heat the waste gas to a temperature range of 780℃-850℃ or above. At this temperature, the pollutant molecules are oxidized and decomposed, and combined with oxygen to produce carbon dioxide and water. The general chemical reaction equation for the oxidation reaction of organic matter is:

[0049] CaHbOcRdNeSf + O2 → CO2 + H2O + HR+NOx+SO2

[0050] Wherein, R represents a halogen element, HR represents a hydrogen halide, N and S represent nitrogen and sulfur elements, and NOx represents nitrogen oxides.

[0051] The waste gas heating system based on the heat generating device of this technical solution adopts a cylindrical poppet valve heating furnace (heating module). The cylindrical poppet valve heating furnace has multiple partitions inside, and each partition is equipped with a heat generating device, that is, a heat storage body with heat generation and heat storage functions. When this system is working, one part of the partition is responsible for the entry of VOCs gas, which is named as the air intake partition; VOCs gas enters the heat treatment chamber in the system after heat exchange with the heat storage body in the air intake partition, and enters another part of the partition for discharge after heat treatment in the heat treatment chamber. This "another part of the partition" is named as the air outlet partition.

[0052] The exhaust gas heating system based on the heat generating device of the present technical solution is internally provided with an inlet and outlet gas distribution system, which includes a number of valves controlled by the instrumentation and electrical control system. By controlling the opening and closing of the valves, the exhaust gas or purified gas is periodically transformed in different partitions to achieve the purpose of heat exchange and heat storage.

[0053] That is, in the above principle description, the heat storage body needs to consume a considerable amount of energy to directly heat the polluted air to a temperature above 780℃-850℃. The heat storage heat recovery system can recover most of the heat energy carried by the VOCs gas after being purified in the heat treatment chamber, and store heat on the heat storage body of the outlet partition. After the heat storage reaches a specified degree, the outlet partition is transformed into the inlet partition after partition transformation, and the stored heat is used to treat the incoming VOCs gas exhaust. This greatly reduces fuel consumption compared to the pure oxidation process without a heat recovery system (ceramic heat storage) design.

[0054] Specifically, the structure of the exhaust gas heating system based on the heat generating device is divided into several parts: the distribution area, the heat storage area and the heat treatment chamber. The heat exchange medium - high-efficiency heat storage ceramic body (heat generating device) is installed in the heat storage area.

[0055] The gas containing VOC waste gas is blown by the fan (a gas power device installed outside the cylindrical poppet valve heating furnace). The distribution area includes the air inlet area, the discharge area and the poppet valve damper mechanical structure separated by the partition. The VOC waste gas first enters through the air inlet area of ​​the system, distributes the flow channel through the poppet valve damper mechanical structure, and then passes through one or more ceramic bodies (i.e., heat storage bodies) in the heat storage area to enter the heat treatment chamber. The ceramic body is preheated actively or in close contact with the hot purified gas (i.e., the high-temperature purified gas generated after the waste gas is heat treated) to make it have a high temperature and can produce efficient heat transfer. As a result, when the gas passes through the ceramic body and reaches the heat treatment chamber, it can be preheated to a temperature close to the oxidation temperature, and the temperature in the heat treatment chamber is further raised to the heat treatment temperature by the ignited burner.

[0056] This system uses a large amount of high-heat-resistant ceramic materials to store and release heat energy. The ceramic material allows airflow to pass freely and provides the largest specific surface area to promote the transfer of heat energy. The ceramic body is fixed in an oxidation tower with internal insulation and connected to a heat treatment chamber with internal insulation.

[0057] The single-fuel burner is installed in the heat treatment chamber, where the thermal oxidation process takes place to purify the exhaust gas. The design of the distribution area mainly directs the VOC-containing gas into the ceramic body in the designated area, and then discharges the clean gas after entering the heat treatment chamber out of the chimney.

[0058] Among them, the exhaust gas lifting valve in the distribution area is the core component of the exhaust gas heating system based on the heat generating device. The exhaust gas is evenly and stably transported to different sectors of the heat storage area through the distribution valve, ensuring the stability of the gas pressure in the exhaust gas pipeline without causing any impact on the various process indicators of the upstream production equipment.

[0059] In order not to affect the rapid heating of production, two Tianshi or McKesson heat treatment machines are installed in the heat treatment room of the system. The volume of the heat treatment room ensures that the residence time of organic waste gas is greater than 1.0s, which can fully decompose the organic waste gas and achieve the best environmental protection effect. The heat treatment device is directly heat treated in the heat treatment room. There is a sufficient thickness of internal insulation inside. It can withstand a maximum instantaneous high temperature of 1200℃ and maintain a temperature of 900℃ for a long time. The average temperature is usually set to 800℃. This temperature can be set according to the working condition. The goal is to completely decompose the organic waste gas and achieve the best energy-saving effect; the outer surface temperature of the furnace body will not exceed the ambient temperature plus 35℃.

[0060] Thermocouples electrically connected to the instrument and control system are installed at both ends of the heat treatment chamber. Their average value is taken during control. At the same time, the high-temperature thermocouple is used for high-temperature alarm and interlocking control. This alarm is interlocked with the system for hardware safety to protect the safe operation of the entire equipment and prevent accidents such as the furnace body being burned by high-temperature gas.

[0061] The exhaust gas heating system based on the heat generating device proposed in this technical solution also includes the following technical elements:

[0062] 1. The concentrated VOCs waste gas is treated by high-temperature thermal storage oxidation. The incinerator adopts a cylindrical lifting valve ventilation structure. The designed service life is not less than 15 years when in full-load production and long-term shutdown. Under normal use and maintenance, it is necessary to ensure that no structural corrosion occurs within 10 years.

[0063] 2. The temperature in the incineration system is maintained between 780-850℃, and the residence time of the heat-treated waste gas in the incineration system is not less than 1.0s, which can make the removal efficiency of VOC in the heat-treated waste gas not less than 99%;

[0064] 3. A grille (304L) is provided in the heat storage area, and a ceramic heat storage body, i.e., a heat storage bed, is arranged on the grille; the ceramic heat storage body adopts Lantai high-efficiency heat storage body with a specific surface area greater than 650M2 / M3, which can ensure low resistance, temperature resistance up to 1200℃, good crack resistance and long service life.

[0065] 4. The shell of the system is made of 6mm steel plate, with reinforcement ribs on the outside, and the shell has good sealing performance. The top of the shell is in the shape of an arc or triangle without gas dead corners, and the shell is equipped with a fire-resistant insulation layer with a thickness of 250-300mm, made of aluminum silicate refractory fiber.

[0066] 5. Each partition of the heat storage area is equipped with an inspection door, which ensures sealing and prevents leakage. The lifting valve adopts a reliable "soft and hard" double-sealed lifting valve.

[0067] 6. Each zone corresponds to 2 lifting valves and 1 purge valve; a total of 22 lifting valves and 11 purge valves.

[0068] 1) Using a high-efficiency lifting valve is conducive to the rapid switching of inlet and outlet gases, ensuring the decomposition efficiency of organic waste gas, achieving environmental protection and saving more heat energy for the system. Using a high-quality valve shaft can maintain a good working condition for a long time under continuous high temperature conditions.

[0069] 2) The lifting valve and purge valve are equipped with external position switches for position indication and alarm. If the valve body is misplaced, the system will automatically "stop".

[0070] 3) The valve plates of the lifting valve and the purge valve are made of stainless steel, which is durable, has good elasticity and toughness, and can ensure the sealing and service life of the system; and as the number of collisions increases, the sealing of the valve will become better and better.

[0071] 7. A fresh air pipeline is set on the exhaust gas heating system based on the heat generating device. A filter is set at the entrance of the fresh air pipeline. The fresh air outlet of the fresh air pipeline is controlled by an automatic valve interlocking. The filtration level of the fresh air outlet is G4. The fresh air pipeline is used for independent heating and cooling and fresh air regulation when the VOCs concentration is too high.

[0072] 8. The exhaust gas heating system based on the heat generating device is equipped with an online VOC concentration measurement (LEL) and alarm interlocking device, which displays the inlet and outlet VOCs concentration and uploads it to the central control room, and reserves a gas detection port. When the gas VOC concentration exceeds the specified dangerous value, an alarm signal is immediately issued, and the heating gas source is automatically shut down. At the same time, the original exhaust gas and natural gas supply of the incineration system are automatically cut off, and the automatic deflation function of the incineration system is turned on, and the original exhaust gas automatically switches to emergency mode;

[0073] 9. The heat treatment room is equipped with an online pressure monitoring device, which is interlocked with the original waste gas and natural gas supply. When the pressure reaches the set value, the system immediately sends out an audible and visual alarm to remind the operator to clean the system. At the same time, the supply of the original waste gas and the natural gas supply of the incineration system is cut off, and the automatic deflation function of the incineration system is turned on. The original waste gas automatically switches to emergency mode;

[0074] 10. The waste gas heating system based on the heat generating device also includes an incineration system;

[0075] 1) The incineration system includes heat treatment controller, UV flame detector, compressed air cooling device, high-pressure igniter, corresponding valve combination, heat treatment chamber pressure monitoring (pressure differential gauge), pre-purging before ignition, flameout protection, over-temperature alarm, gas leakage self-detection and over-temperature fuel supply cut-off functions;

[0076] 2) The incineration system control cabinet is equipped with: flame controller, wind pressure switch, ignition transformer, temperature controller, high temperature limit controller, thermocouple, temperature recorder, etc.

[0077] 11. The waste gas heating system based on the heat generating device is connected to the natural gas pipeline and the natural gas system valve group;

[0078] It includes the main components such as the natural gas main shut-off valve of the main fuel supply and control pipeline, natural gas filter, natural gas flow meter (8 digits), pressure regulating valve, pressure detection gauge, natural gas flow control regulating valve, natural gas leak detector, quick shut-off valve, natural gas pressure regulator, natural gas underpressure protector and natural gas solenoid valve of the ignition burner fuel control pipeline. The main fuel supply and control pipeline and ignition burner fuel control pipeline are required to be tightly connected without any leakage. After installation, a leak test is required and a complete leak test record is required.

[0079] 12. The waste gas heating system based on the heat generating device is connected with a compressed air pipeline and a compressed air system valve group;

[0080] It includes main shut-off valve, compressed air filtration and purification device, compressed air pressure regulating device, compressed air pressure gauge, compressed air automatic switch solenoid valve, compressed air storage tank not exceeding 1m³ and other main components. The compressed air pipeline is required to be tightly connected without any leakage. After installation, a leak test is required, and a complete leak test record is required;

[0081] 13. The incineration system in the heat treatment room must be insulated and protected. Ceramic fiber blocks are used for internal insulation. The thickness of the inner insulation layer must ensure that the temperature of the outer surface of the carbon steel plate on the shady side (the side not directly exposed to sunlight) shall not be higher than the ambient air temperature by 15°C, and all points on all surfaces shall not exceed 70°C (except for thermal bridges); all insulation layers must be folded and caulked to prevent wind and rain from affecting: the internal insulation of the furnace oxidation chamber and regenerator 1 is made of refractory aluminum silicate fiber, which is heat-resistant to 1200°C and has a velvet weight of 220kg / m3. The upper part of the oxidation chamber and regenerator 1 is ~225mm thick, and the inlet and outlet air zone of the regenerator 1 is ~120mm thick. There are three layers of internal insulation, including two layers of aluminum silicate fiber felt and one layer of aluminum silicate fiber module. A heat-resistant steel skeleton is set in the aluminum silicate fiber module and fixed to the furnace shell with anchors. The outer surface of the refractory aluminum silicate fiber is coated with a high-temperature resistant plaster.

[0082] 14. Other requirements:

[0083] 1) A filter is installed at the air inlet of the system's fan. The filter adopts two-stage filtration to ensure that large particles of impurities are not sucked into the furnace by the fan.

[0084] 2) The configured flame arrester can effectively prevent the flashback caused by the heat treatment of flammable gases and cause explosion, ensuring the safety of the system.

[0085] 3) The fan and motor must be explosion-proof, and their selection must be able to suck high-concentration exhaust gas from the high-concentration collection box into the furnace, ensuring that the inside of the air duct at the front end of the fan is in a negative pressure state.

[0086] 4) The heat storage ceramic adopts high-efficiency honeycomb heat storage body with overall dimensions: 150mm×150mm×150mm, hole: 25×25; square groove size: 30mm×30mm×5mm, material: mullite, which can meet the requirements of furnace heat storage and has good gas permeability.

[0087] The exhaust gas heating system based on the heat generating device proposed in this technical solution also includes an instrument and electrical control system:

[0088] The instrument and electrical control system uses the software and hardware of Siemens' Botu S7-1200 / 1500 system PLC for automatic control and is equipped with corresponding monitoring host and human-machine interface to monitor the operating conditions of the entire system in real time.

[0089] In the automation control system of production equipment, the control mode of "centralized monitoring, decentralized control" is adopted:

[0090] Monitoring layer: The monitoring layer exchanges data with the organic waste gas incineration device and control system through industrial Ethernet, monitors the status, faults, etc. of each controlled equipment in the workshop, and conducts central monitoring and historical records.

[0091] Control layer: The control layer is mainly composed of PLC and its system. PLC and its system receive data information sent from the site, and after PLC's own calculation and processing, issue corresponding instructions to control the on-site equipment. All faults of on-site equipment are analyzed and processed in a timely manner, and the fault information is reflected to PLC in real time, and corresponding sound and light prompts are given.

[0092] Equipment layer: The equipment layer is mainly composed of bus modules, frequency converters, field equipment detection elements, field actuators (motors, control valves, etc.), etc. It exchanges data with the PLC in the control layer directly or through the field bus, sends field information to the PLC, and executes equipment actions according to the PLC output instructions.

[0093] The high temperature sensor in the furnace can feedback the furnace temperature information, and proportionally control the heating capacity of the heat processor to keep the furnace temperature stable; the excess waste heat is recovered through the waste heat boiler. When the furnace temperature exceeds the upper limit temperature of 950℃, the system will automatically open the over-temperature discharge valve; when it exceeds the upper limit temperature of 1000℃, the system will automatically alarm and shut down.

[0094] The system uses the negative pressure signal of the pressure sensor at the exhaust gas inlet to control the inlet fan inverter, thereby controlling and adjusting the inlet fan air volume.

[0095] The exhaust gas heating system based on the heat generating device proposed in this technical solution adopts a heating furnace:

[0096] See also Figure 1-Figure 9 The heating furnace of the waste gas heating system based on the heat generating device includes an outer shell 10 and an inspection staircase 4 installed outside the outer shell 10. The inner part of the outer shell 10 is provided with a distribution area, a heat storage chamber 1 and a heat treatment chamber 2 from bottom to top. The three areas form a complete waste gas treatment process, the waste gas is distributed from the distribution area, preheated and heat energy is recovered through the heat storage chamber 1, and finally high-temperature oxidation treatment is carried out in the heat treatment chamber to achieve the purpose of purifying the waste gas.

[0097] A partition is provided between the distribution area and the heat storage chamber 1, and a plurality of valve ports are provided on the partition. The heat storage chamber 1 and the heat treatment chamber 2 are connected. A partition 101 is provided in the heat storage chamber 1 to evenly divide the space of the heat storage chamber 1 into 11 sectors. Multiple sectors can realize the periodic reversing flow of the exhaust gas, improve the efficiency of heat recovery, and make the heat energy distribution more uniform.

[0098] A plurality of exhaust gas outlet lift valves 32, exhaust gas inlet lift valves 31 and purge lift valves 33 are installed at the bottom of the outer shell 10; three valve ports are provided on the partition at the bottom of each sector, and the three valve ports correspond to the exhaust gas inlet lift valve 31, the exhaust gas outlet lift valve 32 and the purge lift valve 33 respectively (that is, a total of 11 exhaust gas outlet lift valves 32, 11 exhaust gas inlet lift valves 31 and 11 purge lift valves 33 are installed at the bottom of the outer shell 10).

[0099] Two annular baffles 102 are provided in the distribution area. The two annular baffles 102 with different inner diameters divide the distribution area into an exhaust gas outlet channel 02, an exhaust gas inlet channel 01 and a purge inlet channel 03. The outer shell 10 is provided with an exhaust gas inlet 11 connected to the exhaust gas inlet channel 01, an exhaust gas outlet 12 connected to the exhaust gas outlet channel 02, and a purge interface 13 connected to the purge inlet channel 03.

[0100] The valve port corresponding to the exhaust gas inlet lift valve 31 also corresponds to the exhaust gas inlet passage 01;

[0101] The valve port corresponding to the exhaust gas outlet lift valve 32 also corresponds to the exhaust gas outlet passage 02;

[0102] The valve port corresponding to the purge lift valve 33 also corresponds to the purge inlet channel 03;

[0103] Preferably, the outer shell 10 is provided with a first heat treatment chamber interface 21 , a second heat treatment chamber interface 22 , a high temperature release port 23 and an explosion relief port 24 connected to the heat treatment chamber 2 .

[0104] Preferably, a poppet valve inspection door 14 is provided on the outer shell 10 and the two annular partitions 102 .

[0105] The exhaust gas heating system based on the heat generating device proposed in this technical solution adopts the following control method.

[0106] The instrument and electrical control system controls the opening and closing of several exhaust gas outlet lift valves 32, exhaust gas inlet lift valves 31 and purge lift valves 33 to control the gas flow in each partition. Since the heat storage chamber adopts an 11-zone design with 5 inlets, 5 outlets and 1 purge for cyclic oxidation, the airflow state of each sector can be independently controlled by the lift valve. Since the heat storage bodies in each sector have different states after working for a long time, the working temperature between the same functional partitions will be different during the cyclic preheating process. This method can detect the temperature by cooperating with thermocouples installed in each sector to detect the temperature state of the heat storage body in each sector, and adjust the inlet and outlet wind direction of the partition through real-time control. The specific steps are as follows:

[0107] S1. System initialization: Start the instrument and electrical control system and initialize the system, including loading the PLC program, starting the monitoring host, and initializing the human-machine interface. Check the status of each exhaust outlet lift valve 32, exhaust inlet lift valve 31, and purge lift valve 33 to ensure that they are in the initial closed position. Check the connection and calibration of thermocouples, pressure sensors and other detection components to ensure that the data is accurate and reliable.

[0108] S2. The system allocates five sectors as air intake sectors, one sector as purge sector, and the remaining five sectors as air outlet sectors, and controls the heat source of the air intake sector (such as turning on the heat processor, electric heater, etc.) to actively preheat the ceramic body therein so that the ceramic body reaches the specified temperature.

[0109] S3. When the ceramic body in the air intake partition reaches the specified temperature, the instrument and electrical control system opens the exhaust gas inlet lift valve 31 corresponding to the air intake partition, and the exhaust gas exchanges heat with the heat storage body in the air intake partition and enters the heat treatment chamber 2 after preheating.

[0110] S3.1. The temperature sensor in the heat treatment chamber 2 monitors the temperature in real time and feeds the data back to the instrumentation and electrical control system;

[0111] S3.2. PLC adjusts the heating capacity of the heat processor according to the temperature data to keep the temperature of the heat treatment chamber within the range of 780℃-850℃;

[0112] S3.3. If the temperature exceeds the upper limit (such as 950℃), the system will automatically open the over-temperature discharge valve; if it exceeds the upper limit (such as 1000℃), the system will alarm and shut down.

[0113] S4. The purified exhaust gas exchanges heat with the heat storage body in the outlet partition. At this time, the hot purifier heats the heat storage body in the outlet partition and stores the heat energy in the heat storage body. During the entire purification process, the instrument and electrical control system monitors and records the real-time temperature of each partition. The outlet partition where the heat storage body that has reached the specified temperature is located is recorded as the preparatory partition.

[0114] S5. The instrument and electrical control system performs balanced control on the temperature of the corresponding partitions according to the temperature deviation value of each partition and the judgment of the preparatory partition. The specific judgment method is:

[0115] If the working temperature of the same functional partition is different, and if there is no preparatory partition, the instrument and electrical control system will adjust the corresponding partition with the deviation value to control the air volume or heat source, so as to balance the temperature. If there is a preparatory partition, the partition function will be switched by switching the corresponding partition with the deviation value, so as to balance the temperature.

[0116] For example, if the temperature of a certain intake partition is low, and there is no preparatory partition in the system, the system controls the exhaust gas inlet lift valve 31 corresponding to the partition to lift, so as to appropriately reduce the intake volume of the partition, improve the preheating effect, and at the same time increase the heat source power of the partition to raise the temperature of the heat storage body of the partition; so as to achieve the effect of balanced temperature control.

[0117] For another example, if the temperature of a certain intake partition is too high, the system controls the exhaust gas inlet lift valve 31 corresponding to the partition to descend, so as to appropriately increase the intake volume of the partition, and at the same time reduce the heat source power of the partition to achieve a cooling effect, thereby achieving the effect of balanced temperature control.

[0118] For another example, if the temperature of a certain air intake partition is relatively low, and there is a preparatory partition in the system in which the heat storage body has been preheated by the purified gas, the system controls the exhaust gas inlet lift valve 31 of this partition (the air intake partition with relatively low temperature) to be closed, and the exhaust gas outlet lift valve 32 to be opened, and the partition becomes the new air outlet partition; at the same time, the system controls the exhaust gas inlet lift valve 31 of the preparatory partition to be opened, and the exhaust gas outlet lift valve 32 to be closed, and the partition becomes the new air intake partition; thereby realizing the functional switching of the two partitions and achieving the effect of balanced temperature control.

[0119] S6. During the entire working process, the instrument and electrical control system monitors the operating status of each valve and the system's pressure, temperature and other parameters in real time. If an abnormal situation is found (such as valve misalignment, excessive pressure, abnormal temperature, etc.), the system will immediately issue an alarm signal. According to the type of alarm, the system will automatically take corresponding protective measures (such as shutting off the heating gas source, cutting off the exhaust gas supply, etc.) and prompt the operator to handle it.

[0120] The operating principle of a rotary valve RTO system in the prior art is given below.

[0121] See also Fig. 9 The rotary valve RTO system is divided into 12 zones, namely a, b, c, d, e, f, g, h, i, j, k, and l. First, the exhaust gas is mixed with fresh air and then enters the rotary valve and the heat storage tank. A 12-zone heat storage tank configuration is adopted. Zones 1 to 5 absorb heat, and the exhaust gas absorbs the heat of the heat storage tank and heats up. The heated exhaust gas then enters the thermal oxidation chamber for oxidation. The oxidized exhaust gas then passes through the heat storage tanks of zones 7 to 11 to heat the heat storage material, and is finally discharged by the rotary valve. The 12th zone heat storage tank also uses a scavenging fan to blow the residual VOC gas in the heat storage tank into the thermal oxidation chamber to avoid cross contamination between the intake and exhaust gases.

[0122] ØThe switching is carried out in the order of intake, purge and exhaust.

[0123] Table 1 is the switching sequence table of the rotary valve RTO system:

[0124] In addition to the source exhaust gas, the rotary RTO intake also has another external air intake for scavenging the thermal storage bed. In the thermal storage bed designed with 12 slots, 5 slots are for source exhaust gas intake, 5 slots are for exhaust, one slot is a blind area, and one slot is a scavenging area. The main function of the scavenging area is that when the thermal storage bed is originally inlet, if it is switched to exhaust, the exhaust gas that has not entered the thermal oxidation chamber will be discharged. Therefore, a scavenging area is set as a purification block before the system is switched to purify the thermal storage bed itself.

[0125] It can be seen that the existing RTO system cannot realize the non-sequential function switching of a single independent partition.

[0126] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A control method for an exhaust gas heating system based on a heat generating device, characterized in that: The instrument and electrical control system can control the opening and closing of a plurality of exhaust gas outlet lift valves (32), an exhaust gas inlet lift valve (31) and a purge lift valve (33) on a heating module in an exhaust gas heating system based on a heat generating device to switch and control the gas flow in each sector in a heat storage area; specifically, the following steps are included: S1. System initialization: Start the instrument and electrical control system and initialize the system, including loading the PLC program in the system, starting the monitoring host, and initializing the human-machine interface; check the status of each lift valve and purge valve; calibrate the thermocouple and pressure sensor; S2. The system allocates five sectors as air intake sectors, one sector as purge sector, and the remaining five sectors as air outlet sectors, and controls the heat source of the air intake sector to actively preheat the ceramic body therein so that the ceramic body reaches the specified temperature; S3. When the ceramic body in the air intake partition reaches the specified temperature, the instrument and electrical control system opens the exhaust gas inlet lift valve (31) corresponding to the air intake partition, and the exhaust gas exchanges heat with the ceramic body in the air intake partition and enters the heat treatment chamber (2) after preheating; S4. The purified exhaust gas exchanges heat with the ceramic body in the outlet partition. At this time, the hot purifier heats the ceramic body in the outlet partition and stores the heat energy in the ceramic body. During the entire purification process, the instrument and electrical control system monitors and records the real-time temperature of each partition, and records the outlet partition where the ceramic body reaches the specified temperature as the preparatory partition. S5. The instrument and electrical control system performs balanced control on the temperature of the corresponding partitions according to the temperature deviation value of each partition and the judgment of the preparatory partition. The specific control method is as follows: If it is found that there is a difference in the working temperature between the same functional partitions, and if there is no preparatory partition, the instrument and electrical control system will adjust the corresponding partition with the deviation value to control the air volume or heat source, so as to balance the temperature; if there is a preparatory partition, the partition function will be switched by switching the corresponding partition with the deviation value.

2. The control method of the exhaust gas heating system based on the heat generating device according to claim 1 is characterized in that: The step S3 is specifically as follows: S3.

1. The temperature sensor in the heat treatment chamber (2) monitors the temperature in real time and feeds the data back to the instrumentation and electrical control system; S3.

2. PLC adjusts the heating capacity of the heat processor according to the temperature data to keep the temperature of the heat treatment chamber within the range of 780℃-850℃; S3.

3. If the temperature exceeds the upper limit, the system will automatically open the over-temperature discharge valve; if it exceeds the upper limit, the system will alarm and shut down.

3. The control method of the exhaust gas heating system based on the heat generating device according to claim 1 is characterized in that: It also includes the step: S6. The operating status of each valve and the pressure and temperature of the system are monitored in real time through the instrument and electrical control system. If an abnormal situation is found, the system immediately sends out an alarm signal. According to the alarm type, the system automatically takes corresponding protection measures and prompts the operator to handle it.

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