High-temperature denitration method based on RTO system under complex working conditions

Abstract

The invention relates to a high-temperature denitration method based on a RTO system under a complex working condition. The method comprises the following steps: feeding waste gas into a lower-layer heat accumulator of a heat accumulation chamber under a gas inlet working condition through a waste gas inlet valve for primary preheating; the waste gas subjected to primary preheating is fed into a denitration reducing agent dynamic mixing chamber, and is uniformly distributed and uniformly flows with a denitration agent in the mixing chamber; feeding the waste gas subjected to uniform distribution and flow of the denitration agent into an upper-layer heat accumulator for secondary preheating; the waste gas is subjected to oxygenolysis of VOCs in the combustion chamber and high-temperature denitration reaction of nitrogen oxides generated by oxidizing nitrogen-containing organic matters and a denitration agent. By arranging the denitration agent pre-gasification chamber and arranging the denitration reducing agent dynamic mixing chamber in the RTO furnace heat storage chamber, the reaction retention time of a reducing agent and waste gas in a high-temperature area is prolonged, the incomplete reaction of the reducing agent entering a smoke discharging and cooling stage along with smoke due to the fact that the reducing agent is directly added into a combustion chamber is solved, the denitration reaction efficiency is improved, and the energy consumption is reduced. The usage amount of a denitration reducing agent is reduced, and the problem that traditional SCR is high in energy consumption is solved.

Description

Technical Field

[0001] The invention relates to a denitration method, in particular to a high-temperature denitration method based on a complex working condition RTO system. Background Art

[0002] With the continuous promotion of the regenerative thermal incinerator (RTO) system in the field of volatile organic compounds (VOCs) treatment, the exhaust gas composition input into the RTO system has become more and more complex. Some nitrogen-containing exhaust gases are prone to generate nitrogen oxides during the RTO incineration process, causing the concentration of nitrogen oxides emitted by the RTO system to approach or exceed the emission limit, bringing risks to the emission standards. Due to the complexity of the RTO system in treating exhaust gas, the differences in concentration and ignition temperature of characteristic pollutants make it difficult to provide a stable catalytic denitrification temperature range (300-400℃) in its thermal storage function area; some special harmful elements will poison the catalyst used for catalytic denitrification, so it is impossible to avoid the problem of catalytic denitrification failure caused by catalyst poisoning. Although the high-temperature zone in the RTO furnace can meet the temperature range (800-900℃) required for high-temperature denitrification (SNCR), the flue gas flow direction is constantly changing due to valve switching, and the reaction time required for high-temperature denitrification cannot be guaranteed; therefore, in order to meet the emission standards and ultra-low emission requirements of nitrogen oxides, flue gas neutralization absorption and SCR denitrification methods are usually used. However, the SCR reaction requires reheating of the flue gas, resulting in high fuel consumption. Therefore, it is particularly urgent to invent a high-temperature denitration method and system for an RTO system based on complex working conditions without generating additional fuel consumption. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method for high-temperature denitration based on an RTO system under complex operating conditions, which can solve the problem of high energy consumption of traditional SCR, eliminate the problem of catalyst poisoning in catalytic denitration, and meet the problem of difficult nitrogen oxide control in RTO incineration of tail gas containing sulfur and chlorine by RTO.

[0004] Technical solution: In order to solve the above technical problems, the present invention provides a high-temperature denitration method based on a complex working condition RTO system, which comprises the following steps: (1) A dynamic mixing chamber for denitrification reducing agent is provided in the furnace body of the regenerative incinerator; (2) The exhaust gas is sent into the lower heat storage body of the heat storage chamber of the intake working condition through the exhaust gas intake valve for preheating, and the preheating temperature is 600℃-700℃; (3) The exhaust gas after primary preheating is sent to the denitrification reducing agent dynamic mixing chamber, where it is evenly distributed and uniformly flows with the denitrification reducing agent; (4) The exhaust gas after the denitrification agent is evenly distributed and uniformly flowed is sent to the upper heat storage body for secondary preheating to 800-900℃; (5) The exhaust gas completes the oxidation decomposition of VOCs in the combustion chamber and the high-temperature denitrification reaction of nitrogen oxides generated by oxidation of nitrogen-containing organic matter with the denitrification agent; (6) The treated flue gas is passed through the upper heat storage body of the heat storage chamber under the exhaust condition, the dynamic mixing chamber of the denitrification reducing agent and the lower heat storage body in turn for heat recovery and cooling, and finally discharged through the flue gas discharge valve.

[0005] Furthermore, a denitrification reducing agent distributor is provided in the denitrification reducing agent dynamic mixing chamber. Before the denitrification reducing agent is input into the denitrification reducing agent distributor, the denitrification agent is pre-gasified in the denitrification agent gasification chamber. The ratio of the pre-gasification gas volume to the RTO treated gas volume is 1:100, and the pre-gasification temperature is 400°C. The mixed gas of the furnace high-temperature flue gas and the purified exhaust flue gas is used as the pre-gasification heat source to reduce the additional energy consumption of the system. The denitrification agent enters the denitrification agent gasification chamber through the atomizing valve group for pre-gasification.

[0006] Furthermore, the combustion chamber of the RTO system provides high-temperature flue gas for gasification premixed denitrification, and the flue gas temperature is 800-900°C. The high-temperature flue gas of the regenerative chamber incinerator and the low-temperature exhaust flue gas are mixed through the denitrification agent blower, the high-temperature bypass valve of the regenerative chamber incinerator and the low-temperature flue gas regulating valve to generate 350-450°C pre-gasification hot flue gas. The pre-gasification hot flue gas accounts for 1% of the total gas processing volume of the regenerative chamber incinerator system, and the mixing ratio of high-temperature flue gas to low-temperature flue gas is about 1:2.

[0007] Furthermore, the dosage of the denitrification reducing agent is adjusted according to the nitrogen oxide data in the exhaust flue gas. The denitrification reducing agent is added only when the exhaust gas enters the denitrification reducing agent dynamic mixing chamber, and is not added when the flue gas enters the denitrification reducing agent dynamic mixing chamber.

[0008] Furthermore, the operating temperature in the dynamic mixing chamber of the denitrification reducing agent changes according to the nitrogen-containing characteristic pollutants contained in the exhaust gas.

[0009] Furthermore, the RTO system includes a regenerative heat incinerator body and a denitrification agent gasification chamber, a denitrification reducing agent dynamic mixing chamber is arranged in the regenerative heat incinerator body, a lower heat storage body is arranged below the denitrification reducing agent dynamic mixing chamber, an upper heat storage body is arranged above the denitrification reducing agent dynamic mixing chamber, a combustion chamber is arranged above the upper heat storage body, a denitrification reducing agent distributor is arranged in the denitrification reducing agent dynamic mixing chamber, the denitrification reducing agent distributor is connected to the denitrification reducing agent gasification chamber through a pipeline, a fan is arranged on the pipeline, the denitrification reducing agent gasification chamber is connected to the combustion chamber through a pipeline, a high-temperature bypass valve is arranged on the pipeline, the denitrification reducing agent gasification chamber is connected to the purified flue gas pipeline through a pipeline, and a low-temperature flue gas regulating valve is arranged on the pipeline between them.

[0010] In the present invention, a more detailed process is as follows: (1) The exhaust gas enters the lower heat storage body of the heat storage chamber under the intake condition through the exhaust gas intake valve for preheating, and the preheating temperature is 600℃-700℃; (2) The exhaust gas after primary preheating is sent to the dynamic mixing chamber of the denitrification reducing agent, where it is evenly distributed and uniformly flows with the denitrification reducing agent; (3) The denitrification agent enters the denitrification agent gasification chamber through the atomizing valve group for pre-gasification; in order to increase the uniform distribution effect of the denitrification reducing agent distributor, the denitrification agent needs to be pre-gasified in the denitrification agent gasification chamber before entering the distributor. The ratio of the pre-gasification gas volume to the RTO treatment gas volume is 1:100, and the pre-gasification temperature is 400℃. The pre-gasification hot flue gas is mixed with the high-temperature flue gas in the furnace and the purified exhaust flue gas to reduce the additional energy consumption of the system.

[0011] (4) The pre-gasified gas is evenly distributed by the denitrification reducing agent distributor and mixed evenly with the preheated exhaust gas in the dynamic mixing chamber; (5) After the denitrification agent is evenly distributed, the exhaust gas enters the upper heat storage body for secondary preheating and finally preheating to 800-900℃ to meet the temperature requirements of the denitrification reduction reaction and the VOCs oxidation reaction. The exhaust gas completes the oxidation destruction of VOCs in the combustion chamber to become clean flue gas, and the nitrogen oxides produced by the oxidation reaction of nitrogen-containing organic matter and the evenly distributed denitrification agent produce high-temperature denitrification (SNCR) reaction to generate harmless nitrogen; (6) The flue gas after oxidation treatment enters the upper heat storage body of the heat storage chamber under exhaust working condition, recovers heat through the upper heat storage body and then cools down, passes through the original agent dynamic mixing chamber, and then enters the lower heat storage body for secondary waste heat recovery, and is discharged through the flue gas discharge valve after cooling down; (7) The combustion chamber of the RTO system provides high-temperature flue gas (800-900°C) for gasification and premixing denitrification; (8) The high-temperature flue gas from the regenerative chamber incinerator and the low-temperature exhaust flue gas are mixed through the denitrification agent blower, the high-temperature bypass valve of the regenerative incinerator and the low-temperature flue gas regulating valve to generate 350-450°C pre-gasification hot flue gas; (9) The hot flue gas used for pre-gasification accounts for 1% of the total gas volume processed by the regenerator incinerator system, and the mixing ratio of high-temperature flue gas to low-temperature flue gas is approximately 1:2; (10) The amount of denitrification agent is automatically adjusted according to the data of nitrogen oxides in the flue gas. The denitrification reducing agent is added only when the exhaust gas enters the dynamic mixing chamber. It is not added when the flue gas enters the dynamic mixing chamber. The addition of the denitrification reducing agent is automatically controlled by the program; (11) The denitrification agent is atomized in the denitrification reducing agent gasification premixing zone through a dual-fluid spray gun, so that the denitrification reducing agent is gasified and premixed to a state of 300-350° C. to form a denitrification reducing gas; (12) The denitrification reduction gas is sent to the denitrification reduction distributor through the blower; (13) The rhythm of the denitrification reduction gas being sent to each heat storage chamber through the denitrification agent blower is automatically controlled by the program; (14) The denitration reaction is completed in the combustion chamber. When the flue gas passes through the denitration reducing agent dynamic mixing chamber, the denitration reducing gas is not added; (15) The working temperature in the dynamic mixing chamber of the denitrification reducing agent is automatically controlled by a temperature control system to the optimum temperature corresponding to the characteristic nitrogen-containing pollutants contained in the exhaust gas; (16) The cooled flue gas discharged through the flue gas discharge valve enters the flue gas post-treatment facilities of the complex working condition RTO system, undergoes secondary purification of other harmful substances, and is then sent to the chimney for discharge after passing the purification; (17) The denitration reduction gas shut-off valve on each regenerator is synchronized with the operation process of the regenerator incinerator system air intake valve to ensure that the exhaust gas can be mixed with the denitration reduction gas when it is inhaled; (18) The mixed gas undergoes a high-temperature denitration reaction in the high-temperature denitration reduction reaction zone to remove NOx from the gas; (19) The mixed gas undergoes VOCs oxidation reaction in the regenerator incinerator to remove pollutants in the gas; (20) The completely reacted gas is then cooled to about 70°C through the heat storage chamber for heat recovery and then discharged through the flue gas exhaust valve.

[0012] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: A dynamic mixing chamber for denitrification reducing agent is set in the body of the regenerative incinerator to increase the reaction residence time of the reducing agent and the exhaust gas in the high temperature zone and improve the denitrification reaction efficiency. The pre-gasification system is used to pre-treat the denitrification reducing agent, which improves the uniform distribution effect and reaction activity of the reducing agent; By controlling the amount of denitrification agent, the denitrification process is optimized; The working temperature in the dynamic mixing chamber of the denitrification reducing agent changes according to the characteristic nitrogen-containing pollutants contained in the exhaust gas to ensure that the denitrification reaction is carried out at the optimal temperature; Improve denitrification efficiency: By increasing the reaction residence time and optimizing the distribution of the reducing agent, the denitrification efficiency is significantly improved, effectively solving the problem of nitrogen oxide emissions under complex working conditions; Reduce energy consumption: Compared with traditional SCR technology, the present invention does not need to reheat the flue gas, which greatly reduces the energy consumption of the system; Avoid catalyst poisoning: Adopting the principle of high-temperature denitration (SNCR), there is no need to use easily poisoned catalysts, which improves the applicability and stability of the system; Adaptability to complex working conditions: The present invention is particularly suitable for treating waste gas containing complex components such as nitrogen-containing organic matter, sulfides, chlorides, etc., and solves the technical difficulties of traditional RTO systems under such working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a structural schematic diagram of the RTO system in the present invention. DETAILED DESCRIPTION

[0014] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0015] The high-temperature denitration method based on a complex working condition RTO system of the present invention comprises the following steps: (1) A dynamic mixing chamber for denitrification reducing agent is provided in the furnace body of the regenerative incinerator; (2) The exhaust gas is sent into the lower heat storage body of the heat storage chamber of the intake working condition through the exhaust gas intake valve for preheating, and the preheating temperature is 600℃-700℃; (3) The exhaust gas after primary preheating is sent to the denitrification reducing agent dynamic mixing chamber arranged in the heat storage chamber of the RTO furnace, and evenly distributes and flows with the denitrification agent; (4) The exhaust gas after the denitrification agent is evenly distributed and uniformly flowed is sent to the upper heat storage body for secondary preheating to 800-900℃; (5) The exhaust gas completes the oxidation decomposition of VOCs in the combustion chamber and the high-temperature denitrification reaction of nitrogen oxides generated by oxidation of nitrogen-containing organic matter with the denitrification agent; (6) The treated flue gas is passed through the upper heat storage body, dynamic mixing chamber and lower heat storage body of the heat storage chamber under the exhaust condition in turn for heat recovery and cooling, and finally discharged through the flue gas discharge valve.

[0016] The denitrification agent described in step (3) is pretreated, comprising the following steps: (1) Before the denitrification agent is input into the distributor, the denitrification agent is pre-gasified in the gasification chamber. The ratio of the pre-gasification gas volume to the RTO treatment gas volume is 1:100, and the pre-gasification temperature is 400°C; (2) Use the mixed gas of the furnace high-temperature flue gas and the purified exhaust flue gas as the pre-gasification heat source to reduce the additional energy consumption of the system.

[0017] The dosage of denitrification reducing agent is adjusted according to the nitrogen oxide data in the exhaust flue gas. The denitrification reducing agent is added only when the exhaust gas enters the dynamic mixing chamber of the denitrification reducing agent, and is not added when the flue gas enters the dynamic mixing chamber of the denitrification reducing agent.

[0018] The operating temperature in the dynamic mixing chamber of the denitrification reducing agent changes according to the characteristic nitrogen-containing pollutants contained in the exhaust gas.

[0019] like Figure 1 As shown, the RTO system includes a regenerative incinerator body 1 and a denitrification agent gasification chamber 2, a denitrification reducing agent dynamic mixing chamber 3 is arranged in the regenerative incinerator body 1, a lower heat storage body 4 is arranged below the denitrification reducing agent dynamic mixing chamber 3, an upper heat storage body 5 is arranged above the denitrification reducing agent dynamic mixing chamber 3, a combustion chamber 6 is arranged above the upper heat storage body 5, a denitrification reducing agent uniform distributor 7 is arranged in the denitrification reducing agent dynamic mixing chamber 3, the denitrification reducing agent uniform distributor 7 is connected to the denitrification reducing agent gasification chamber 2 through a pipeline, a fan 8 is arranged on the pipeline, the denitrification reducing agent gasification chamber 2 is connected to the combustion chamber 6 through a pipeline, a high-temperature bypass valve 9 is arranged on the pipeline, the denitrification reducing agent gasification chamber 2 is connected to the purified flue gas pipeline 10 through a pipeline, and a low-temperature flue gas regulating valve 11 is arranged on the pipeline between them.

[0020] The present invention sets a dynamic mixing chamber for denitrification reducing agent in the furnace body of a regenerative incinerator, thereby increasing the reaction residence time of the reducing agent and the exhaust gas in the high temperature zone and improving the denitrification reaction efficiency; adopts a pregasification system to pretreat the denitrification reducing agent, thereby improving the uniform distribution effect and reaction activity of the reducing agent; optimizes the denitrification process by controlling the amount of the denitrification agent; the working temperature in the dynamic mixing chamber for the denitrification reducing agent changes according to the nitrogen-containing characteristic pollutants contained in the exhaust gas, thereby ensuring that the denitrification reaction is carried out at an optimal temperature; significantly improves the denitrification efficiency by increasing the reaction residence time and optimizing the distribution of the reducing agent, and effectively solves the problem of nitrogen oxide emission under complex working conditions; compared with the traditional SCR technology, the present invention does not need to reheat the flue gas, thereby greatly reducing the energy consumption of the system; adopts the principle of high-temperature denitrification (SNCR), does not need to use a catalyst that is easily poisoned, and improves the applicability and stability of the system; the present invention is particularly suitable for treating exhaust gas containing complex components such as nitrogen-containing organic matter, sulfide, chloride, etc., and solves the technical difficulties of the traditional RTO system under such working conditions.

[0021] The present invention provides a thought and method. There are many methods and ways to implement the technical solution. The above is only the preferred implementation mode of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the protection scope of the present invention. All components not specified in this embodiment can be implemented by existing technologies.

Claims

1. A high temperature denitration method based on a complex working condition RTO system, characterized in that: It includes the following steps, (1) A dynamic mixing chamber for denitrification reducing agent is provided in the furnace body of the regenerative incinerator; (2) The exhaust gas is sent into the lower heat storage body of the heat storage chamber of the intake working condition through the exhaust gas intake valve for preheating, and the preheating temperature is 600℃-700℃; (3) The exhaust gas after primary preheating is sent to the denitrification reducing agent dynamic mixing chamber, where it is evenly distributed and uniformly flows with the denitrification reducing agent; (4) The exhaust gas after the denitrification agent is evenly distributed and uniformly flowed is sent to the upper heat storage body for secondary preheating to 800-900℃; (5) The exhaust gas completes the oxidation decomposition of VOCs in the combustion chamber and the high-temperature denitrification reaction of nitrogen oxides generated by oxidation of nitrogen-containing organic matter with the denitrification agent; (6) The treated flue gas is passed through the upper heat storage body of the heat storage chamber under the exhaust condition, the dynamic mixing chamber of the denitrification reducing agent and the lower heat storage body in turn for heat recovery and cooling, and finally discharged through the flue gas discharge valve.

2. The high temperature denitration method based on the complex working condition RTO system according to claim 1, characterized in that: A denitrification reducing agent distributor is provided in the denitrification reducing agent dynamic mixing chamber. Before the denitrification reducing agent is input into the denitrification reducing agent distributor, the denitrification agent is pre-gasified in the denitrification agent gasification chamber. The ratio of the pre-gasification gas volume to the RTO treatment gas volume is 1:100, and the pre-gasification temperature is 400°C. The mixed gas of the furnace high-temperature flue gas and the purified exhaust flue gas is used as the pre-gasification heat source to reduce the additional energy consumption of the system. The denitrification agent enters the denitrification agent gasification chamber through the atomizing valve group for pre-gasification.

3. The high temperature denitration method based on the complex working condition RTO system according to claim 2 is characterized in that: The combustion chamber of the RTO system provides high-temperature flue gas for gasification premixed denitrification. The flue gas temperature is 800-900℃. Through the denitrification agent blower, the high-temperature bypass valve of the regenerative incinerator and the low-temperature flue gas regulating valve, the high-temperature flue gas of the regenerative chamber incinerator and the low-temperature exhaust flue gas are mixed to generate 350-450℃ pre-gasification hot flue gas. The pre-gasification hot flue gas accounts for 1% of the total gas treatment volume of the regenerative chamber incinerator system. The mixing ratio of high-temperature flue gas to low-temperature flue gas is about 1:

2.

4. The high temperature denitration method based on complex working condition RTO system according to claim 1, characterized in that: The dosage of denitrification reducing agent is adjusted according to the nitrogen oxide data in the exhaust flue gas. The denitrification reducing agent is added only when the exhaust gas enters the dynamic mixing chamber of the denitrification reducing agent, and is not added when the flue gas enters the dynamic mixing chamber of the denitrification reducing agent.

5. The high temperature denitration method based on complex working condition RTO system according to claim 1, characterized in that: The operating temperature in the dynamic mixing chamber of the denitrification reducing agent changes according to the characteristic nitrogen-containing pollutants contained in the exhaust gas.

6. The high temperature denitration method based on complex working condition RTO system according to claim 3, characterized in that: The RTO system comprises a regenerative incinerator furnace body (1) and a denitrification agent gasification chamber (2). A denitrification reducing agent dynamic mixing chamber (3) is provided in the regenerative incinerator furnace body (1). A lower heat storage body (4) is provided below the denitrification reducing agent dynamic mixing chamber (3). An upper heat storage body (5) is provided above the denitrification reducing agent dynamic mixing chamber (3). A combustion chamber (6) is provided above the upper heat storage body (5). A denitrification reducing agent uniform distributor (7) is provided in the denitrification reducing agent dynamic mixing chamber (3). The denitrification reducing agent uniform distributor (7) is connected to the denitrification reducing agent gasification chamber (2) through a pipeline. A fan (8) is provided on the pipeline. The denitrification reducing agent gasification chamber (2) is connected to the combustion chamber (6) through a pipeline. A high-temperature bypass valve (9) is provided on the pipeline. The denitrification reducing agent gasification chamber (2) is connected to a purified flue gas pipeline (10) through a pipeline. A low-temperature flue gas regulating valve (11) is provided on the pipeline between them.

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