CN114984750A - Heat exchange reaction emission reduction method of nitrous gas fixed bed - Google Patents
Heat exchange reaction emission reduction method of nitrous gas fixed bed Download PDFInfo
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- CN114984750A CN114984750A CN202210641963.4A CN202210641963A CN114984750A CN 114984750 A CN114984750 A CN 114984750A CN 202210641963 A CN202210641963 A CN 202210641963A CN 114984750 A CN114984750 A CN 114984750A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
- B01D53/8631—Processes characterised by a specific device
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/005—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by heat treatment
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/343—Heat recovery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02C—CAPTURE, STORAGE, SEQUESTRATION OR DISPOSAL OF GREENHOUSE GASES [GHG]
- Y02C20/00—Capture or disposal of greenhouse gases
- Y02C20/10—Capture or disposal of greenhouse gases of nitrous oxide (N2O)
Abstract
The invention discloses a heat exchange reaction emission reduction method of a nitrous gas fixed bed, which comprises the following parts: the nitrite-containing waste gas to be treated is washed by a liquid separation tank and then is introduced into the nitrite gas emission reduction device through a cold path of the cold gas heat exchanger and a cold path of the hot gas heat exchanger in sequence, a heat exchange device is arranged in the nitrite gas emission reduction device, the terminal of the heat exchange device is connected with a waste heat boiler, an electric preheater is arranged at the inlet of the nitrite gas emission reduction device, and the outlet of the nitrite gas emission reduction device is connected with a hot path of the hot gas heat exchanger, a denitration reactor, a hot path of the cold gas heat exchanger and a chimney in sequence. The process method fully utilizes the catalytic heat release phenomenon in the emission reduction reaction, fully utilizes the heat generated in the reaction process to preheat the feed gas, and provides heat for the denitration reaction. Meanwhile, a special nitrous gas emission reduction device is designed, and redundant heat in the system can be effectively led out in a mode of combining with a heat pipe, so that efficient and stable operation of the system is guaranteed.
Description
Technical Field
The invention relates to a heat exchange reaction emission reduction method of a nitrous gas fixed bed.
Background
Adipic acid is an important chemical raw material, the yield of the adipic acid is increased year by year, but industrial waste gas containing greenhouse gas N2O is generated in the production process of the adipic acid, the greenhouse effect of N2O is 310 times of that of equivalent CO2, and N2O can react with VOCs in the atmosphere under the illumination condition to form photochemical toxicant, destroy the ozone layer and destroy the ecological environment, so the treatment is necessary.
The adipic acid production waste gas treatment technology mainly comprises a direct thermal decomposition technology and a catalytic decomposition technology, wherein the direct thermal decomposition technology needs to be carried out at the temperature of over 1100 ℃, and new energy waste and a greenhouse gas CO2 emission source are generated in the treatment process; the N2O catalytic decomposition technology is to carry out N2O decomposition reaction under the action of a catalyst and under a mild condition, in the reaction process, except for the requirement of external energy to raise the reaction system to the activation temperature of the catalyst at the initial reaction stage, no external energy is needed, the reaction is a strong exothermic reaction, and the heat required by the reaction system is maintained by the exothermic heat of the decomposition reaction.
However, the catalytic decomposition reaction generates a large amount of heat, and when the amount of heat exceeds a certain range, the reaction continues and the safety of the whole machine is affected, so in practical use, it is necessary to design a heat dissipation device or a heat recovery device to recover and discharge the excess heat.
However, a reasonable and effective preparation process can realize the efficient and low-cost recovery treatment of the whole waste gas.
Disclosure of Invention
The invention aims to solve the defects of the prior art and provides a heat exchange reaction emission reduction method of a nitrous gas fixed bed. The treatment process embodies the principles of energy conservation, emission reduction, high efficiency and environmental protection waste gas treatment, the nitrous gas emission reduction catalyst is used for treating the adipic acid production waste gas by adopting a catalyst decomposition technology, and the catalytic decomposition technology is used for treating N 2 O effect, N 2 The decomposition rate of O is more than 95 percent, and N 2 Decomposition of O to N 2 、O 2 The selectivity of (a) is greater than 99%.
A heat exchange reaction emission reduction method of a nitrous gas fixed bed comprises the following steps:
the nitrite-containing waste gas to be treated is washed by a liquid separation tank and then is introduced into the nitrite gas emission reduction device through a cold path of the cold gas heat exchanger and a cold path of the hot gas heat exchanger in sequence, a heat exchange device is arranged in the nitrite gas emission reduction device, the terminal of the heat exchange device is connected with a waste heat boiler, an electric preheater is arranged at the inlet of the nitrite gas emission reduction device, and the outlet of the nitrite gas emission reduction device is connected with a hot path of the hot gas heat exchanger, a denitration reactor, a hot path of the cold gas heat exchanger and a chimney in sequence.
In order to guarantee the high efficiency of reaction to and more effectual carry out effectual derivation and more accurate temperature control with the heat that produces in the reaction process, nitrous gas subtract the row ware for horizontal structure, inside is equipped with a plurality of consecutive catalyst frame beds, is equipped with the heat pipe bed between the adjacent catalyst frame bed, the heat pipe bed lead out the heat to exhaust-heat boiler through the heat pipe structure in.
The process aims at the treatment scheme of the industrial waste gas which does not need to be diluted, the industrial waste gas to be treated can not be diluted during treatment, a compressed air diluting device is not arranged at the outlet of the liquid separating device, and the concentration of the nitrous gas is controlled to be 25-60%.
In order to ensure the stable and efficient reaction, the nitrous gas emission reduction device is filled with a catalyst, and the temperature of the exhaust gas in the nitrous gas emission reduction device is controlled to be 740-760 ℃ through a heat exchange device after the catalytic reaction.
In order to ensure the controllability of the reaction and provide a certain heat input for the initial reaction process, the electric preheater is an air electric preheater, and the air electric preheater is used for controlling the temperature of the input gas in the nitrous gas reducer to be 440-460 ℃.
In order to improve the heat exchange efficiency, the hot gas heat exchanger is a floating head shell-and-tube heat exchanger, the material is 304H or 16MnR, and the same cold gas heat exchanger can also adopt a similar structural design.
Furthermore, the top of the liquid separation tank is provided with a raw material gas feed inlet, the middle of the liquid separation tank is provided with a process water washing layer, the process water washing layer is used for removing suspended particles and liquid drops, and the bottom of the liquid separation tank is provided with a demisting device and a raw material gas outlet.
Further, in the nitrous gas emission reducer, the nitrous gas is decomposed into nitrogen and oxygen, wherein the temperature of the flue gas after decomposition is controlled to be 720-cost 760 ℃, and after heat exchange is carried out through a hot gas heat exchanger, the temperature is reduced to 400-cost 450 ℃, and then the flue gas enters a denitration reactor to carry out SCR denitration reaction.
Further, the temperature of the waste gas containing the nitrates to be treated after the waste gas passes through the cold gas preheater for the first time is 140-.
For easy understanding, and also to prevent unnecessary misunderstanding, the main functions of the cold gas heat exchanger and the hot gas heat exchanger in the present application are explained below, in which the gas in the cold path of the cold gas heat exchanger absorbs heat, the gas in the cold path of the hot gas heat exchanger absorbs heat, the gas in the hot path of the hot gas heat exchanger releases heat, and the gas in the hot path of the cold gas preheater releases heat.
Has the advantages that:
the invention relates to a treatment process without dilution for waste gas, and has the following characteristics and advantages:
1. before entering the system, adipic acid waste gas is sprayed by process water, and is pre-filtered by a liquid separating tank to enter a subsequent system. This operation can be effectual washes the particulate matter in the waste gas to make gas further purer, will be easily dissolved in the gas of water and carry out preliminary recovery, go on with the steady of guaranteeing subsequent reaction.
2. Aiming at the characteristic that the nitrous gas emission reduction reaction is a catalytic decomposition reaction, the heat released in the catalytic decomposition reaction is effectively recovered, so that the follow-up continuous reaction can be ensured without using additional energy supplement, the energy input cost of the whole emission reduction process is solved, and meanwhile, in the catalytic reaction process, the temperature in the emission reduction reactor can be effectively controlled through an internal heat exchange device.
3. The invention has compact integral structure and composition, and effectively improves the redundant flow of the existing catalytic reaction, so that the emission reduction process is more efficient and energy-saving, the use of resources is reduced, and the efficiency of the catalytic reaction is synchronously improved.
Drawings
FIG. 1 is an overall flow diagram of an abatement process;
1. the system comprises a liquid separation tank 2, a cold air heat exchanger 3, a hot air heat exchanger 4, an electric preheater 5, a nitrous gas emission reducer 6, a denitration reactor 7, a waste heat boiler 8, a heat pipe heat exchanger 9 and a chimney.
Detailed Description
For the purpose of enhancing the understanding of the present invention, the present invention will be further described in detail with reference to the following examples and the accompanying drawings, which are only used for explaining the present invention and are not to be construed as limiting the scope of the present invention.
As shown in fig. 1, an undiluted treatment process for exhaust gas includes the following main components and functions to be performed by the main components.
And in the liquid separation tank 1, feed gas enters the liquid separation tank from the top for pre-filtration, process water is sprayed into the middle position of the liquid separation tank according to the gas inflow to be washed, suspended particles and liquid drops are removed, and the feed gas is demisted and separated and then discharged from the side surface of the bottom.
The waste gas to be treated is preheated by three-stage heat exchange of a cold gas heat exchanger 2, a hot gas heat exchanger 3 and an electric air preheater 4, so that the temperature of the feed gas entering the nitrous gas emission reducer 5 is 445 ℃.
The nitrous gas is decomposed into nitrogen and oxygen under the action of a catalyst. And the reacted gas is discharged into a hot gas heat exchanger 3 at 750 ℃ for heat exchange and then enters a denitration reactor 6.
The temperature of SCR denitration reaction is 450 ℃, NOx carried in the feed gas reacts with ammonia water under the action of the denitration catalyst, and the content of NOx in the flue gas is less than 50mg/Nm3 after the NOx leaves the denitration reactor 6.
The denitrated flue gas is discharged through a chimney 9 after heat exchange between the cold air heat exchanger 2 and the inlet feed gas.
The waste heat in the nitrous gas emission reduction device 5 is taken out by the heat pipe exchanger 8 and is subjected to byproduct steam by the waste heat boiler 8, so that the nitrous gas emission reduction device can be used for daily work and life.
On the whole, this flue gas heat transfer system releases heat and provides the feed gas when fully utilizing nitrous gas catalytic decomposition, through air conditioning heat exchanger 2, hot gas heat transfer 3 second grade heat exchanges, ensures that the temperature of feed gas satisfies nitrous gas catalytic decomposition's start-up temperature, utilizes electric air heater 4 to heat the feed gas in the stage of starting the stove. The hot gas heat exchanger 3 adopts 16MnR, and the heat exchanger adopts a floating head shell-and-tube heat exchanger.
The nitrous gas emission reduction device 5 and the heat pipe heat exchanger 8 are used jointly, a fixed bed heat exchange reactor is arranged, a catalyst frame bed layer and a heat pipe heat exchange bed layer are arranged in the reactor, multiple layers of spaced bed layers are arranged, and heat pipe heat exchange working media adopt heat conducting mother materials. Wherein the catalyst adopted in the nitrous gas emission reduction device 5 is a WYY-001 catalyst developed in aerospace Whitlet production.
And in the reaction process, gradually switching the heat exchange bed layers of the heat pipes into a working state, and when the temperature of the system reaches 780 ℃ and gives an alarm, and the temperature reaches 795-800 ℃, closing the feed gas inlet valve of the feed gas inlet valve, and emergently emptying the system. After the furnace is started, when the temperature of the system is lower than 480 ℃, alarming, and when the temperature is between 450 and 480 ℃, switching the heat exchange bed layers of the heat pipe into a closed state step by step until the temperature in the emission reduction reactor is not lower than 450 ℃. The temperature in the system is controlled to be 450-750 ℃, the stable and safe nitrous gas emission reduction reaction and the stable catalytic decomposition reaction are ensured through temperature linkage control, and the nitrous gas emission reduction rate reaches 95%.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (10)
1. A heat exchange reaction emission reduction method of a nitrous gas fixed bed is characterized by comprising the following steps:
the nitrite-containing waste gas to be treated is washed by a liquid separation tank and then is introduced into the nitrite gas emission reduction device through a cold path of the cold gas heat exchanger and a cold path of the hot gas heat exchanger in sequence, a heat exchange device is arranged in the nitrite gas emission reduction device, the terminal of the heat exchange device is connected with a waste heat boiler, an electric preheater is arranged at the inlet of the nitrite gas emission reduction device, and the outlet of the nitrite gas emission reduction device is connected with a hot path of the hot gas heat exchanger, a denitration reactor, a hot path of the cold gas heat exchanger and a chimney in sequence.
2. A heat exchange reaction emission reduction method of a nitrous gas fixed bed according to claim 1, wherein said nitrous gas emission reducer is of a horizontal structure, a plurality of catalyst frame beds connected in sequence are arranged inside the nitrous gas emission reduction reducer, a heat pipe bed is arranged between adjacent catalyst frame beds, and the heat pipe bed guides heat out to a waste heat boiler through a heat pipe structure.
3. A heat exchange reaction emission reduction method of a nitrous gas fixed bed according to claim 1, wherein a compressed air diluting device is not provided at an outlet of the liquid separating device, and the concentration of the nitrous gas is controlled to be 25% -60%.
4. The heat exchange reaction emission reduction method of the nitrous gas fixed bed according to claim 1, wherein a catalyst is filled in the nitrous gas emission reduction device, and the temperature of the exhaust gas in the nitrous gas emission reduction device is controlled to 740-760 ℃ through a heat exchange device after the catalytic reaction.
5. The heat exchange reaction emission reduction method for the nitrous gas fixed bed according to claim 1, wherein the electric preheater is an air electric preheater, and the air electric preheater is used for controlling the temperature of the input gas in the nitrous gas reducer to be 440-460 ℃.
6. A heat exchange reaction emission reduction method for a nitrous gas fixed bed according to claim 1, wherein the hot gas heat exchanger is a floating head shell-and-tube heat exchanger, and is made of 304H or 16 MnR.
7. A heat exchange reaction emission reduction method for a nitrous gas fixed bed according to claim 1, characterized in that a raw material gas feed inlet is arranged at the top of the liquid separation tank, a process water washing layer is arranged in the middle of the liquid separation tank and used for removing suspended particles and liquid drops, and a demisting device and a raw material gas outlet are arranged at the bottom of the process water washing layer.
8. The heat exchange reaction emission reduction method of the nitrous gas fixed bed as claimed in claim 1, wherein the nitrous gas is decomposed into nitrogen and oxygen in the nitrous gas emission reduction device, wherein the temperature of the flue gas after decomposition is controlled to be 760 ℃ in 720-.
9. The heat exchange reaction emission reduction method for the nitrous gas fixed bed according to claim 1, wherein the temperature of the to-be-treated waste gas containing the nitrous gas after passing through the cold gas preheater for the first time is 140-160 ℃, and the temperature after passing through the hot gas heat exchanger for the first time is 400-450 ℃.
10. A nitrous gas fixed bed heat exchange reaction emission reduction method as claimed in claim 1, wherein, the gas in the cold path of cold gas heat exchanger absorbs heat, the gas in the cold path of hot gas heat exchanger absorbs heat, the gas in the hot path of hot gas heat exchanger releases heat, the gas in the hot path of cold gas preheater releases heat.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210641963.4A CN114984750A (en) | 2022-06-08 | 2022-06-08 | Heat exchange reaction emission reduction method of nitrous gas fixed bed |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210641963.4A CN114984750A (en) | 2022-06-08 | 2022-06-08 | Heat exchange reaction emission reduction method of nitrous gas fixed bed |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH054027A (en) * | 1991-06-28 | 1993-01-14 | Asahi Chem Ind Co Ltd | Treatment of exhaust gaseous dinitrogen monoxide |
| CN101439260A (en) * | 2008-12-04 | 2009-05-27 | 浙江大学 | System for removing nitrous oxides in low-temperature flue gas and technique thereof |
| CN106110848A (en) * | 2016-07-13 | 2016-11-16 | 成都普瑞得科技有限公司 | The method that nitrogen oxides emission-reducing system reduces discharging with nitrogen oxides |
| CN113144890A (en) * | 2021-05-12 | 2021-07-23 | 北京工业大学 | Waste gas purification system and method containing high-concentration laughing gas |
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2022
- 2022-06-08 CN CN202210641963.4A patent/CN114984750A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH054027A (en) * | 1991-06-28 | 1993-01-14 | Asahi Chem Ind Co Ltd | Treatment of exhaust gaseous dinitrogen monoxide |
| CN101439260A (en) * | 2008-12-04 | 2009-05-27 | 浙江大学 | System for removing nitrous oxides in low-temperature flue gas and technique thereof |
| CN106110848A (en) * | 2016-07-13 | 2016-11-16 | 成都普瑞得科技有限公司 | The method that nitrogen oxides emission-reducing system reduces discharging with nitrogen oxides |
| CN113144890A (en) * | 2021-05-12 | 2021-07-23 | 北京工业大学 | Waste gas purification system and method containing high-concentration laughing gas |
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