A method for regulating and controlling the temperature of a heat storage chamber based on a heat storage combustion device

Abstract

The present invention discloses a heat storage chamber temperature regulation control method based on a heat storage combustion device, comprising: setting a temperature sensor on the upper layer of each heat storage chamber in the heat storage combustion device, determining the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature at this moment according to the temperature sensor, using the heat storage chamber with the highest temperature as the air inlet chamber, using the heat storage chamber with the lowest temperature as the air outlet chamber, and finding the operation cycle corresponding to the heat storage combustion device to be updated according to the air inlet chamber and the air outlet chamber; calculating the temperature difference between the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature, finding the cumulative multiple of the corresponding valve group switching according to the temperature difference, and determining the operation cycle time corresponding to the heat storage combustion device; determining the current operation cycle of the heat storage combustion device, and changing the operation cycle time corresponding to the heat storage combustion device to be updated according to the update strategy. This method is helpful to achieve the unity of pollution reduction and carbon reduction.

Description

Technical Field

[0001] The invention relates to the technical field of regenerative combustion devices, and in particular to a regenerative chamber temperature regulation and control method based on a regenerative combustion device. Background Art

[0002] Regenerative Thermal Oxidizer (RTO) is the most efficient and stable VOCs treatment equipment in the VOCs treatment process and is widely used in VOCs treatment in the chemical, pharmaceutical and other industries.

[0003] As global warming poses a serious challenge to human survival, pollution reduction and carbon reduction in the pollution control process are receiving more and more attention. In the conventional use scenario of RTO, the VOCs concentration is not enough to maintain self-heating, and fossil fuels such as natural gas need to be added to assist combustion, which will produce a large amount of carbon emissions. Although the pollution reduction effect is good, carbon reduction still needs to be focused on.

[0004] The temperature of RTO for efficient decomposition of VOCs should generally be maintained above 760°C, and VOCs will be completely decomposed after staying in the combustion chamber of RTO for a period of time. Due to air flow disturbance and uneven temperature field, the temperature distribution in the combustion chamber will be uneven. In order to ensure the decomposition efficiency of VOCs, the monitored low point of the combustion chamber temperature must also reach the set value, which generally increases the consumption of natural gas and carbon emissions. Summary of the invention

[0005] In view of the problems existing in the prior art, the present invention provides a temperature regulation and control method for a heat storage chamber based on a heat storage combustion device, which helps to improve the decomposition efficiency of RTO on VOCs and, at the same time, reduce the additional natural gas consumption caused by uneven temperature distribution, thereby achieving the unity of pollution reduction and carbon reduction.

[0006] In order to achieve the above technical objectives, the present invention adopts the following technical solution: a method for regulating and controlling the temperature of a regenerative chamber of a regenerative combustion device, comprising the following steps:

[0007] (1) A temperature sensor is arranged on the upper layer of each regenerator in the regenerative combustion device, and the regenerator with the highest temperature and the regenerator with the lowest temperature at that moment are determined according to the temperature sensor, and the regenerator with the highest temperature is used as the air inlet chamber, and the regenerator with the lowest temperature is used as the air outlet chamber, and the operation cycle corresponding to the regenerative combustion device to be updated is found according to the air inlet chamber and the air outlet chamber;

[0008] (2) Calculate the temperature difference between the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature, find the cumulative multiple of the corresponding valve group switching according to the temperature difference, and determine the corresponding operating cycle time of the heat storage combustion device;

[0009] (3) Determine the current operating cycle of the thermal storage combustion device, and according to the update strategy, change the operating cycle time corresponding to the thermal storage combustion device to be updated according to the operating cycle time corresponding to the thermal storage combustion device determined in step (2).

[0010] Further, in step (2), when the temperature difference is less than 10°C, the cumulative multiple of the valve group switching is 0; when 10°C < temperature difference ≤ 20°C, the cumulative multiple of the valve group switching is 1; when 20°C < temperature difference ≤ 30°C, the cumulative multiple of the valve group switching is 2; when 30°C < temperature difference ≤ 40°C, the cumulative multiple of the valve group switching is 3; when 40°C < temperature difference ≤ 50°C, the cumulative multiple of the valve group switching is 4; when 50°C < temperature difference ≤ 60°C, the cumulative multiple of the valve group switching is 5; when 60°C < temperature difference ≤ 70°C, the cumulative multiple of the valve group switching is 6; when 70°C < temperature difference ≤ 80°C, the cumulative multiple of the valve group switching is 7; when 80°C < temperature difference ≤ 90°C, the cumulative multiple of the valve group switching is 8 When the temperature difference is 90℃, the cumulative multiple of the valve group switching is 8; when the temperature difference is greater than 90℃, the cumulative multiple of the valve group switching is 9.

[0011] Furthermore, the updating process of the operation cycle time corresponding to the regenerative combustion device is as follows:

[0012] Operation cycle time = valve group switching cumulative time × valve group switching cumulative multiple + valve group switching reference time.

[0013] Furthermore, the update strategy is: finding out that the operating cycle corresponding to the thermal storage combustion device to be updated is executed after the current operating cycle of the thermal storage combustion device, and the operating cycle corresponding to the thermal storage combustion device to be updated is closest to the current operating cycle of the thermal storage combustion device.

[0014] Furthermore, an air inlet, an air outlet and a purge port are provided below each heat storage chamber, the air inlet is connected to the main fan in the heat storage combustion device through an air inlet valve, the air outlet is connected to the exhaust pipe in the heat storage combustion device through an air outlet valve, and the purge port is connected to the purge fan in the heat storage combustion device through a purge valve.

[0015] Furthermore, the air inlet valve, air outlet valve, purge valve and temperature sensor are all connected to a PLC control system.

[0016] Furthermore, the number of heat storage chambers in the heat storage combustion device is no less than 5.

[0017] Compared with the prior art, the present invention has the following beneficial effects: the present invention is based on the heat storage chamber temperature regulation and control method of the heat storage combustion device. Through the temperature difference between the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature, the accumulated multiples of the corresponding valve group switching are found, and the corresponding operation cycle time of the heat storage combustion device is determined. The intake air is low-temperature gas, and the heat storage chamber with the highest temperature is used as the intake chamber. Prolonging the intake time can take away more heat from the heat storage chamber; at the same time, the exhaust air is high-temperature gas, and the heat storage chamber with the lowest temperature is used as the exhaust chamber. Prolonging the exhaust time can increase the temperature of the heat storage chamber through high-temperature exhaust, thereby achieving the temperature of the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature to be uniform. The temperature is evenly maintained above the set value, which can prolong the residence time of the exhaust gas in the high-temperature combustion chamber, thereby achieving complete oxidation of the exhaust gas and improving the purification efficiency; at the same time, the heat storage chamber temperature regulation and control method of the present invention does not need to increase the consumption of natural gas, thereby achieving the coordinated treatment of pollution reduction and carbon reduction. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is further explained below in conjunction with embodiments.

[0019] RTO mainly uses high temperature to oxidize and decompose VOCs. For certain VOCs, temperature will affect the purification efficiency. If the temperature distribution is uneven, the low-temperature section of the regenerator will not be able to achieve the designed purification efficiency for VOCs. Considering the investment cost, the combustion chamber will not be built very large, and the residence time of VOCs in the combustion chamber is limited. The overall purification efficiency of VOCs will be affected. At the same time, in order to ensure that the temperature of the RTO regenerator reaches the set value, the temperature will be increased by increasing the amount of natural gas combustion at the points with lower temperature in the regenerator. This method will bring additional natural gas The consumption of gas increases the operating cost and carbon emissions; and in the thermal storage combustion device of the present invention, an air inlet, an air outlet and a purge port are provided at the bottom of each thermal storage chamber, and the air inlet is connected to the main fan in the thermal storage combustion device through an air inlet valve, and the air outlet is connected to the exhaust pipe in the thermal storage combustion device through an air outlet valve, and the purge port is connected to the purge fan in the thermal storage combustion device through a purge valve. A temperature sensor is provided on the upper layer of each thermal storage chamber, and the air inlet valve, air outlet valve, purge valve and temperature sensor are all connected to the PLC control system, and there are no less than 5 thermal storage chambers in the thermal storage combustion device. On this basis, the present invention provides a thermal storage chamber temperature adjustment and control method based on a thermal storage combustion device, which specifically includes the following steps:

[0020] (1) A temperature sensor is arranged on the upper layer of each regenerator in the regenerative combustion device, and the regenerator with the highest temperature and the regenerator with the lowest temperature at that moment are determined according to the temperature sensor, and the regenerator with the highest temperature is used as the air inlet chamber, and the regenerator with the lowest temperature is used as the air outlet chamber, and the operation cycle corresponding to the regenerative combustion device to be updated is found according to the air inlet chamber and the air outlet chamber;

[0021] (2) Calculate the temperature difference between the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature, find the cumulative multiple of the corresponding valve group switching based on the temperature difference, and determine the corresponding operating cycle time of the heat storage combustion device. In the present invention, when the temperature difference is less than 10°C, the cumulative multiple of the valve group switching is 0; when 10°C < temperature difference ≤ 20°C, the cumulative multiple of the valve group switching is 1; when 20°C < temperature difference ≤ 30°C, the cumulative multiple of the valve group switching is 2; when 30°C < temperature difference ≤ 40°C, the cumulative multiple of the valve group switching is 3; when 40°C < temperature difference ≤ 50°C, the cumulative multiple of the valve group switching is 4; when 50°C < temperature difference ≤ 60°C, the cumulative multiple of the valve group switching is 5; when 60°C < temperature difference ≤ 70°C, the cumulative multiple of the valve group switching is 6; when 70°C < temperature difference ≤ 80°C, the cumulative multiple of the valve group switching is 7; when 80°C < temperature difference ≤ When the temperature difference is 90℃, the cumulative multiple of the valve group switching is 8; when the temperature difference is greater than 90℃, the cumulative multiple of the valve group switching is 9. This process sets different cumulative multiples of the valve group switching according to the size of the temperature difference, so that the temperature can be adjusted quickly when the temperature difference is large, and the temperature can be adjusted accurately when the temperature difference is small.

[0022] The process of determining the operation cycle time corresponding to the regenerative combustion device in the present invention is as follows:

[0023] Operation cycle time = valve group switching cumulative time × valve group switching cumulative multiple + valve group switching reference time.

[0024] The above method is used to extend the corresponding operating cycle time of the heat storage combustion device. Since the intake air is low-temperature gas, the heat storage chamber with the highest temperature is used as the intake chamber. Prolonging the intake time can take away more heat from the heat storage chamber. At the same time, the outlet gas is high-temperature gas, and the heat storage chamber with the lowest temperature is used as the outlet chamber. Prolonging the exhaust time can increase the temperature of the heat storage chamber through high-temperature exhaust, thereby achieving a uniform temperature trend between the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature. Maintaining the temperature uniformly above the set value can extend the residence time of the exhaust gas in the high-temperature combustion chamber, thereby achieving complete oxidation of the exhaust gas and improving the purification efficiency. At the same time, the heat storage chamber temperature adjustment and control method of the present invention does not require additional natural gas consumption, thereby achieving coordinated treatment of pollution reduction and carbon reduction.

[0025] (3) determining the current operating cycle of the thermal storage combustion device, and according to the update strategy, changing the operating cycle time corresponding to the thermal storage combustion device to be updated according to the operating cycle time corresponding to the thermal storage combustion device determined in step (2); the update strategy in the present invention is: finding out that the operating cycle corresponding to the thermal storage combustion device to be updated is executed after the current operating cycle of the thermal storage combustion device, and the operating cycle corresponding to the thermal storage combustion device to be updated is closest to the current operating cycle of the thermal storage combustion device.

[0026] The heat storage chamber temperature regulation and control method of the heat storage combustion device of the present invention prolongs the operation cycle time of the air inlet chamber and the air outlet chamber to improve the uniformity of the heat storage chamber temperature, thereby improving the purification efficiency and realizing the coordinated treatment of VOCs pollution reduction and carbon reduction. Example

[0027] There are 5 regenerators in the regenerative combustion device of this embodiment, and their operation cycles are shown in Table 1, wherein in the T1 cycle, i.e., the first cycle, regenerators 1# and 2# are air inlet chambers, regenerators 3# and 4# are exhaust chambers, and regenerator 5# is a purge chamber. The exhaust gas is heated by the hot regenerators below the parallel regenerators 1# and 2# and then enters the combustion chamber above the RTO for full combustion. The temperature of the combustion chamber is generally controlled to be above 760°C, and the residence time is 1s. Then, the exhaust gas is cooled by the cold regenerators below the regenerators 3# and 4# and then discharged. The exhaust temperature generally does not exceed 100°C. The exhaust valve pipeline is provided with insulation, and the heat exchange efficiency can generally reach 90%; the main function of the purge chamber is to blow back the VOCs remaining below the regenerator into the combustion chamber, ensuring that the purification efficiency of the multi-chamber RTO reaches more than 98%. Each operation cycle lasts for 60s. After the T1 cycle ends, the RTO reversing valve switches to the T2 cycle. The main difference between the T2 cycle and the T1 cycle is that the 5# exhaust valve of the heat storage chamber stops purging and opens to become the exhaust chamber, and the 3# exhaust valve of the heat storage chamber is closed for purging and becomes the purge chamber. After the same time, it enters the T3 cycle, and repeats in sequence. After T10, it cycles back to T1.

[0028] Table 1: Operation cycle of thermal storage combustion device

[0029]

[0030] In the above-mentioned heat storage combustion device, it is measured that the average temperature of the upper layer of the heat storage chamber at this moment is 600°C, and the temperature of heat storage chamber 1# is the highest, which is 630°C. As the air inlet chamber, the temperature of heat storage chamber 4# is the lowest, which is 580°C. As the air outlet chamber, look up Table 1, and the operation cycles that satisfy heat storage chamber 1# as the air inlet chamber and heat storage chamber 4# as the air outlet chamber are T1, T2, and T10; the temperature difference between the highest temperature and the lowest temperature is 50°C, and the corresponding cumulative multiple of valve group switching is 4 according to the temperature difference, and the updated operation cycle time = valve group switching cumulative time × valve group switching cumulative multiple + valve group switching reference time = 1×4 + 60 =64s. If the current operation cycle has reached T10, the operation time of T1 is adjusted to 64s; if the current operation cycle has reached T1, the operation time of T2 is adjusted to 64s; if the current operation cycle has reached any operation cycle from T2 to T9, the operation time of T10 is adjusted to 64s.

[0031] By monitoring the operating cycle Tx in which VOCs exhaust gas enters the heat storage chamber with the highest temperature and exits the heat storage chamber with the lowest temperature, the operating cycle Tx can be appropriately extended to ultimately achieve relatively uniform and stable temperatures in each combustion chamber.

[0032] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A method for regulating and controlling the temperature of a regenerator of a regenerative combustion device, characterized in that: The steps include: (1) A temperature sensor is arranged on the upper layer of each regenerator in the regenerative combustion device, and the regenerator with the highest temperature and the regenerator with the lowest temperature at that moment are determined according to the temperature sensor, and the regenerator with the highest temperature is used as the air inlet chamber, and the regenerator with the lowest temperature is used as the air outlet chamber, and the operation cycle corresponding to the regenerative combustion device to be updated is found according to the air inlet chamber and the air outlet chamber; (2) Calculate the temperature difference between the heat storage chamber with the highest temperature and the heat storage chamber with the lowest temperature, find the cumulative multiple of the corresponding valve group switching according to the temperature difference, and determine the corresponding operating cycle time of the heat storage combustion device; When the temperature difference is less than 10℃, the cumulative multiple of the valve group switching is 0; when 10℃<temperature difference≤20℃, the cumulative multiple of the valve group switching is 1; when 20℃<temperature difference≤30℃, the cumulative multiple of the valve group switching is 2; when 30℃<temperature difference≤40℃, the cumulative multiple of the valve group switching is 3; when 40℃<temperature difference≤50℃, the cumulative multiple of the valve group switching is 4; when 50℃<temperature difference≤60℃, the cumulative multiple of the valve group switching is 5; when 60℃<temperature difference≤70℃, the cumulative multiple of the valve group switching is 6; when 70℃<temperature difference≤80℃, the cumulative multiple of the valve group switching is 7; when 80℃<temperature difference≤ When the temperature is 90℃, the cumulative multiple of the valve group switching is 8; when the temperature difference is greater than 90℃, the cumulative multiple of the valve group switching is 9; The process of determining the operation cycle time corresponding to the regenerative combustion device is as follows: Operation cycle time = valve group switching cumulative time × valve group switching cumulative multiple + valve group switching reference time; Determine the current operation cycle of the regenerative combustion device, and according to the update strategy, change the operation cycle time corresponding to the regenerative combustion device to be updated according to the operation cycle time corresponding to the regenerative combustion device determined in step (2); An air inlet, an air outlet and a purge port are provided below each heat storage chamber. The air inlet is connected to the main fan in the heat storage combustion device through an air inlet valve, the air outlet is connected to the exhaust pipe in the heat storage combustion device through an air outlet valve, and the purge port is connected to the purge fan in the heat storage combustion device through a purge valve.

2. The method for controlling the temperature of the regenerator of a regenerative combustion device according to claim 1, characterized in that: The update strategy is: find out that the operation cycle corresponding to the thermal storage combustion device to be updated is executed after the current operation cycle of the thermal storage combustion device, and the operation cycle corresponding to the thermal storage combustion device to be updated is closest to the current operation cycle of the thermal storage combustion device.

3. The method for regulating and controlling the temperature of the regenerator of a regenerative combustion device according to claim 1, characterized in that: The air inlet valve, air outlet valve, purge valve and temperature sensor are all connected to the PLC control system.

4. The method for regulating and controlling the temperature of the regenerator of a regenerative combustion device according to claim 1, characterized in that: The number of heat storage chambers in the heat storage combustion device is no less than 5.

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