CN114307637A

CN114307637A - Reactor for denitration treatment of waste gas of power plant

Info

Publication number: CN114307637A
Application number: CN202210078372.0A
Authority: CN
Inventors: 孙震; 薛冬梅; 顾时雨; 王星浩
Original assignee: China India Hengsheng Beijing Trading Co ltd
Current assignee: China India Hengsheng Beijing Trading Co ltd
Priority date: 2022-01-24
Filing date: 2022-01-24
Publication date: 2022-04-12

Abstract

The invention discloses a reactor for denitration treatment of waste gas of a power plant, and provides a technology capable of stably treating nitrogen oxide after the time from the inflow of the waste gas to the treatment of the nitrogen oxide. The denitration reactor is filled with a catalyst containing Ir, and the catalyst can reduce nitrogen oxides contained in the exhaust gas, and is used as a pre-denitration gas treatment of the exhaust gas and the denitration reactor before flowing into the denitration reactor. After passing through the heat exchanger, the denitration gas is heated by heat exchange with the denitration gas, and the denitration gas is cooled at the same time.

Description

Reactor for denitration treatment of waste gas of power plant

Technical Field

The invention discloses a reactor for denitration treatment of power plant waste gas, and particularly relates to denitration equipment for treating nitrogen oxides in the power plant waste gas.

Background

Among the common methods for treating nitrogen oxides in exhaust gas, the ammonia catalytic reduction method is the main decomposition reduction method. The ammonia process reduction methods are divided into two categories: the Selective Catalytic Reduction (SCR) and the selective non-catalytic reduction (SNCR) have reaction mechanisms that ammonia is used as a reducing agent to reduce NOX in flue gas into harmless nitrogen and water, and the main difference between the SCR and the SNCR is that the SCR uses a catalyst and the reaction temperature is lower, and the SNCR does not use the catalyst and has higher reaction temperature. The ammonia catalytic reduction method converts NO and NO2 contained in the waste gas discharged from the nitric acid production process into nontoxic gas nitrogen which is directly discharged into the air. The cost of ammonia as a reducing agent and the heating cost for raising the temperature of the exhaust gas are increased, and the method greatly increases the operation cost in the flue gas denitration work.

Disclosure of Invention

The invention aims to provide denitration equipment for treating nitrogen oxides in waste gas of a power plant, and provides the following device and a treatment method in order to reduce operation cost and successfully achieve the aim of carrying out denitration treatment by using an Ir catalyst: a denitration reactor contains a catalyst of Ir which can reduce nitrogen oxides contained in exhaust gas. After the denitration gas is heat-exchanged by the heat exchanger, the pre-denitration gas is heated by heat exchange with the denitration gas (exhaust gas flowing out from the denitration step) while the denitration gas is cooled.

The denitration device comprises a heater, and the heating amount of the heater can be adjusted to heat the pre-denitration gas; and a thermometer that detects a temperature of the gas on the side of the denitration reactor of the heater before flowing into the denitration reactor. The apparatus further includes a first densitometer for detecting the concentration of nitrogen oxides in the gas, and a second densitometer for detecting the concentration of nitrogen oxides in the denitrated gas. A bypass line for bypassing the denitration gas to the heat exchanger before denitration, a bypass flow controller for adjusting a flow rate of the denitration gas flowing through the bypass line, and a bypass exhaust heat recovery device in the bypass line.

The bypass exhaust heat recovery device is disposed on the downstream side of the flow of the denitrification gas from the flow controller, exchanges heat between the denitrification gas and the refrigerant, cools the denitrification gas, and heats the refrigerant, and a heater is provided that includes a heating unit that heats the gas flowing into the denitrification reactor and a heating amount adjusting unit that adjusts the amount of heating by the heating unit so that the temperature detected by the thermometer is within a target temperature range. The heating amount adjusting unit determines the denitration rate in the denitration reactor according to the concentration of the nitrogen oxide detected by the first density meter.

In the denitration device, NOx is reduced by using a catalyst containing Ir without using ammonia, so that the operation cost can be reduced. Further, in the denitration device, when the temperature of the gas flowing into the denitration reactor is low, the gas is heated by the heater, and in the denitration device, the heat exchanger also heats the pre-denitration gas, so that the consumption of heat energy in the heater heating the pre-denitration gas can be reduced.

In the denitration apparatus, the heating amount in the heating unit is adjusted in accordance with the temperature detected by the thermometer, so that the temperature of the pre-denitration gas flowing into the denitration reactor is stabilized and contained in the pre-denitration gas. The nitrogen oxides can be continuously and stably reduced. Further, unnecessary heating by the heating unit can be reduced, and running cost can be reduced.

With the lapse of time, the gas temperature of the denitration reactor buccal Ir catalyst is increased, and the denitration rate is gradually enhanced. In addition, when the hydrogen concentration or the carbon monoxide concentration in the exhaust gas changes, the temperature range in which the denitration reaction occurs in the denitration reactor also changes. In the denitration device, the target temperature range is changed to increase the denitration rate required by the denitration rate calculation means. Therefore, even if the catalyst deteriorates with time or the hydrogen concentration or the carbon monoxide concentration in the exhaust gas changes, the temperature of the pre-denitration gas adjusted by the heating amount adjustment unit changes, resulting in denitration.

In the above denitration device, the heating unit may include a burner for injecting the combustible fluid, and the heating amount adjustment unit may include a flow rate adjustment valve that adjusts a flow rate of the combustible fluid supplied to the burner, and a controller that controls a valve opening degree of the flow control valve according to a temperature detected by the thermometer.

In the denitration apparatus according to any of the above embodiments, the heating amount adjusting means may adjust the heating amount of the heating apparatus so that the temperature is within the target temperature range by detection of the thermometer before the exhaust gas of the gas generation source flows into the denitration reactor.

Drawings

FIG. 1 is a schematic view of a denitration apparatus according to the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, fig. 1 is a schematic view of a denitration apparatus according to an embodiment of the present invention, wherein the denitration apparatus 1 includes a denitration reactor 10, a heat exchanger 15, a heater 20, and a thermometer 29. The denitration reactor 10 reduces nitrogen oxides contained in the exhaust gas, and the heat exchanger 15 exchanges heat between the pre-denitration gas before flowing into the denitration reactor 10 and the denitration gas EXa (exhaust gas EX) flowing out of the denitration reactor 10. The heater 20 heats the exhaust gas EX. The thermometer 29 detects the temperature of the exhaust gas EX. The denitration reactor 10 contains a catalyst 11 of Ir in a reaction vessel, which can reduce nitrogen oxides contained in the exhaust gas EX. The reaction vessel of the denitration reactor 10 is constituted by a pre-denitration gas inlet 12 into which the pre-denitration gas EXb flows and a denitration gas outlet 13, into which the pre-denitration gas EXb flows, and from which the denitration gas EXa flows out.

Claims

1. A reactor for denitration treatment of exhaust gas of a power plant, comprising a denitration reactor containing a catalyst containing Ir for reducing nitrogen oxides contained in the exhaust gas, the denitration gas being cooled by heat exchange between a pre-denitration gas (exhaust gas before flowing into the denitration reactor) and a denitration gas (exhaust gas flowing out of the denitration reactor) while cooling the denitration gas, a heat exchanger for heating the front gas; the denitration device also comprises a heater, and the heating amount of the heater can be adjusted so as to heat the gas before denitration after the gas passes through the heat exchanger.

2. The reactor of claim 1, wherein the reactor is used for denitration treatment of exhaust gas from a power plant, and comprises: the apparatus comprises a first densitometer for detecting the concentration of nitrogen oxides in the pre-denitrated gas, a second densitometer for detecting the concentration of nitrogen oxides in the denitrated gas, and a bypass line bypassing the denitrated gas that has flowed out of the denitration reactor and has not yet flowed into the heat exchanger.

3. The reactor of claim 1, wherein the reactor is used for denitration treatment of exhaust gas from a power plant, and comprises: the heater comprises a heating unit for heating the gas flowing into the denitration reactor and a heating amount adjusting unit, wherein the heating amount adjusting unit adjusts the heating amount through the heating unit so that the temperature detected by the thermometer falls within a target temperature range; the heating amount adjusting unit determines the denitration rate in the denitration reactor according to the concentration of the nitrogen oxide detected by the first density meter and the concentration of the nitrogen oxide detected by the second density meter; a calculation unit: the target changing unit that changes the target temperature range so that the denitration rate becomes high and the heating amount of the heating unit are heated so that the temperature detected by the thermometer is determined to be within the target temperature range.

4. The reactor for denitration treatment of exhaust gas of power plant according to claim 1, wherein said heating amount adjusting unit heats the exhaust gas of the gas generation source so that the temperature detected by the thermometer is still within the target temperature range before the exhaust gas flows into the denitration reactor.

5. The reactor of claim 1, wherein the reactor is used for denitration treatment of exhaust gas from a power plant, and comprises: the target temperature of the denitration device is controlled between 200 and 300 ℃.

6. The reactor of claim 1, wherein the reactor is used for denitration treatment of exhaust gas from a power plant, and comprises: the denitration device is additionally provided with a denitration performance enhancing gas supply device which is used for supplying denitration performance enhancing gas containing at least one of hydrogen or carbon monoxide to the pre-denitration gas.

7. The denitration performance-enhanced gas supply apparatus according to claim 6, wherein: the denitration performance enhancing gas supply device has a gas flow rate adjusting valve for adjusting the flow rate of the denitration performance enhancing gas supplied to the pre-denitration gas and the concentration of nitrogen oxide detected by the second densimeter; accordingly, a controller for controlling a valve opening of a denitration performance enhancing gas flow control valve is provided.

8. The reactor of claim 1, wherein the reactor is used for denitration treatment of exhaust gas from a power plant, and comprises: the catalyst is distributed in the reactor along the flow direction of the exhaust gas, wherein the temperature distribution controller is configured to adjust the temperature distribution of the catalyst so that the temperature of the catalyst at all positions in the flow direction is within a predetermined temperature range.