Sulfuric acid process flue gas SCR denitration device

Abstract

The invention relates to the technical field of sulfuric acid process flue gas purification, in particular to a sulfuric acid process flue gas SCR denitration device which comprises an SCR reactor, a gas supply assembly used for providing ammonia gas is arranged on a gas inlet pipeline of the SCR reactor, and a detection assembly used for monitoring gas concentration is arranged on a gas outlet pipeline of the SCR reactor; an ammonia-smoke mixer is arranged in one end, close to a gas inlet pipeline of the SCR reactor, of the SCR reactor, and a plurality of denitration assemblies are arranged in one end, close to a gas outlet pipeline of the SCR reactor, of the SCR reactor. Through the cooperation of the gas supply assembly, the ammonia-smoke mixer in the SCR reactor and the plurality of denitration assemblies, the clean flue gas emission of nitrogen oxides (NOX) in the sulfuric acid final emission tail gas can reach 15 mg / Nm < 3 > (standard dryness) or below, the ultra-clean emission requirement that the ammonia escape is less than 1 mg / Nm < 3 > (standard dryness) is met, and the quality of a sulfuric acid product is improved.

Description

Technical Field

[0001] This invention relates to the field of sulfuric acid process flue gas purification technology, and in particular to a sulfuric acid process flue gas SCR denitrification device. Background Technology

[0002] In the sulfuric acid production process, raw materials such as sulfur, pyrite, and hydrogen sulfide are burned at high temperatures. During combustion, nitrogen in the air is oxidized to produce NO. X NO emissions X Concentration between 100-200 mg / m³ 3 Between. With the increasing stringency of national environmental protection requirements, the environmental indicators for non-power industries are also constantly rising, necessitating stricter control over nitrogen oxides (NOx) in flue gas. X The vehicle undergoes denitrification treatment to meet national emission standards before being discharged. The initial stage removes NOx. X The flue gas can significantly reduce the concentration of nitrogen oxides in the downstream sulfuric acid products, thereby improving the quality of sulfuric acid products.

[0003] Currently, SNCR (Synthetic Non-Conforming Catalytic Reduction) is used for flue gas denitrification in sulfuric acid processes, which involves denitrification at temperatures of 800-1100℃. However, SNCR denitrification efficiency is only around 70%, which is relatively low, making it difficult to achieve high-efficiency denitrification and obtain higher-quality sulfuric acid. This results in lower NOx emissions from the flue gas. X It is even more difficult to reach 15mg / Nm 3 (Standard) and below ultra-clean emission requirements.

[0004] The SCR denitrification process commonly used in thermal power plants has high denitrification efficiency, but it requires a large amount of flue gas, a large scale of equipment, a large amount of ammonia, a wide flow control range of ammonia regulating valves, and low requirements for clean flue gas emission control, making it easier to select the corresponding equipment.

[0005] However, the characteristics of sulfuric acid process gas are: (1) small gas volume, small ammonia consumption, and higher requirements for clean flue gas emission control (NOx). X (1) NH3), commonly used ammonia regulating valves cannot meet the requirements for precise ammonia addition. (2) The sulfur dioxide concentration in sulfuric acid process gas is very high, and the impact of sulfur dioxide concentration on denitrification devices is unknown. Many manufacturers of SCR denitrification catalysts commonly used in thermal power plants dare not venture into flue gas denitrification of sulfuric acid process gas. (3) The flue gas temperature of sulfuric acid process gas is between 420 and 450 degrees Celsius, which exceeds the temperature limit of commonly used medium-temperature catalysts in thermal power plants, and also exceeds the temperature limit of commonly used steel. (4) Positive pressure operation places higher demands on the SCR reactor. Flue gas leakage can cause accidents, which is fundamentally different from negative pressure flue gas denitrification in thermal power plants. (5) Emission indicators are higher than those required by thermal power plants.

[0006] Therefore, there is an urgent need for a sulfuric acid process flue gas SCR denitrification device that can reduce nitrogen oxides (NOx) in the final sulfuric acid emission tail gas. XClean flue gas emissions reach 15 mg / Nm 3 (Standard) or below, ammonia slip is less than 1 mg / Nm³. 3 (Standard) ultra-clean emission requirements, and improve the quality of sulfuric acid products. Summary of the Invention

[0007] The purpose of this invention is to provide an SCR denitrification device for sulfuric acid process flue gas to solve the problems existing in the prior art.

[0008] To achieve the above objectives, the present invention provides the following solution: a sulfuric acid process flue gas SCR denitrification device, comprising an SCR reactor, wherein an ammonia supply component is provided on the inlet pipe of the SCR reactor, and a gas concentration monitoring component is provided on the outlet pipe of the SCR reactor; an ammonia flue gas mixer is provided at one end of the inlet pipe of the SCR reactor, and multiple denitrification components are provided at one end of the outlet pipe of the SCR reactor.

[0009] Preferably, the gas supply assembly includes an electric heat tracing constant temperature box, in which a liquid ammonia cylinder is installed. The outlet of the liquid ammonia cylinder is connected to an ammonia buffer tank, which is connected to an inlet of an ammonia-air mixer. The outlet of the ammonia-air mixer is connected to an ammonia injection grid, which is located inside the inlet pipe of the SCR reactor.

[0010] Preferably, the other air inlet of the ammonia-air mixer is connected to an instrument compressed air buffer tank.

[0011] Preferably, a linear flow regulating valve is installed on the pipeline connecting the ammonia buffer tank and the ammonia-air mixer.

[0012] Preferably, the detection components include a CEMS and an ammonia slip detector, wherein the CEMS and the ammonia slip detector are installed on the outlet pipe of the SCR reactor.

[0013] Preferably, the denitrification assembly includes a flow equalization plate, and a catalyst is disposed at the outlet end of the flow equalization plate. Both the flow equalization plate and the catalyst are installed inside the SCR reactor.

[0014] Preferably, the catalyst is a rare earth catalyst.

[0015] Preferably, the inlet pipe of the SCR reactor is connected to the outlet of the sulfuric acid process gas self-heating exchanger.

[0016] Preferably, the gas outlet pipe of the SCR reactor is connected to the inlet of the sulfur dioxide catalyst converter.

[0017] The present invention discloses the following technical effects:

[0018] This invention, through the coordination of a gas supply component, an ammonia fume mixer within the SCR reactor, and multiple denitrification components, enables the reduction of nitrogen oxides (NOx) in the final sulfuric acid emission tail gas. X Clean flue gas emissions reach 15 mg / Nm 3 (Standard) or below, ammonia slip is less than 1 mg / Nm³. 3 (Standard) ultra-clean emission requirements, and improve the quality of sulfuric acid products. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the sulfuric acid flue gas SCR denitrification device of the present invention;

[0021] The components include: 1. Liquid ammonia cylinder; 2. Electric heating constant temperature box; 3. Ammonia buffer tank; 4. Linear flow regulating valve; 5. Instrument compressed air buffer tank; 6. Ammonia air mixer; 7. Ammonia injection grid; 8. SCR reactor; 9. Ammonia fume mixer; 10. Flow equalization plate; 11. Catalyst; 12. CEMS; and 13. Ammonia slip detector. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] Example 1

[0025] Reference Figure 1This invention provides a sulfuric acid process flue gas SCR denitrification device, including an SCR reactor 8, an ammonia supply component installed on the inlet pipe of the SCR reactor 8, a detection component for monitoring gas concentration installed on the outlet pipe of the SCR reactor 8, an ammonia flue gas mixer 9 installed at one end of the inlet pipe of the SCR reactor 8, and multiple denitrification components installed at one end of the outlet pipe of the SCR reactor 8.

[0026] SCR reactor 8, short for Selective Catalytic Reduction Reactor, is an environmental protection device used for flue gas denitrification. It uses a catalyst to react a reducing agent (ammonia or urea) with nitrogen oxides (NOx). X The reaction produces nitrogen gas and water vapor.

[0027] This invention, through the coordination of a gas supply component, an ammonia fume mixer within the SCR reactor, and multiple denitrification components, enables the reduction of nitrogen oxides (NOx) in the final sulfuric acid emission tail gas. X Clean flue gas emissions reach 15 mg / Nm 3 (Standard) or below, ammonia slip is less than 1 mg / Nm³. 3 (Standard) ultra-clean emission requirements, and improve the quality of sulfuric acid products.

[0028] Further optimization of the scheme: the gas supply component includes an electric heating constant temperature box 2, a liquid ammonia cylinder 1 installed inside the electric heating constant temperature box 2, an ammonia buffer tank 3 connected to the outlet of the liquid ammonia cylinder 1, an ammonia buffer tank 3 connected to an inlet of an ammonia-air mixer 6, an ammonia spray grid 7 connected to the outlet of the ammonia-air mixer 6, and the ammonia spray grid 7 installed in the inlet pipe of the SCR reactor 8.

[0029] The liquid ammonia in the liquid ammonia cylinder 1 is heated and vaporized into ammonia gas by the electric heating constant temperature box 2 and sent into the ammonia buffer tank 3. The ammonia buffer tank 3 then delivers the ammonia gas to the ammonia-air mixer 6.

[0030] To further optimize the design, the other air inlet of the ammonia-air mixer 6 is connected to the instrument-grade compressed air buffer tank 5.

[0031] The compressed air is compressed by the instrument compressed air buffer tank 5, and then the compressed air is delivered to the ammonia-air mixer 6.

[0032] The ammonia-air mixer 6 mixes ammonia and compressed air and delivers the mixture to the ammonia injection grid 7, so that the mixture of ammonia and compressed air is initially mixed with the sulfuric acid process flue gas in the inlet pipe of the SCR reactor 8.

[0033] Buffer tanks are primarily used in various systems to buffer pressure fluctuations, making the system operate more smoothly. The buffering performance of a buffer tank is mainly achieved by compressing the air inside the tank. There are two types of buffer tanks: diaphragm-type and air-bladder-type.

[0034] To further optimize the design, a linear flow regulating valve 4 is installed on the pipeline connecting the ammonia buffer tank 3 and the ammonia-air mixer 6.

[0035] The linear flow control valve 4 is a type of control valve that controls flow rate changes by adjusting the opening degree. Its opening degree and flow rate have a linear proportional relationship under constant pressure difference. This valve has four flow control characteristics: linear, equal percentage, parabolic, and quick-opening.

[0036] The amount of ammonia gas used is precisely regulated by a high-precision, wide-range linear flow regulating valve 4.

[0037] The scheme was further optimized, and the detection components included CEMS12 and ammonia slip detector 13. CEMS12 and ammonia slip detector 13 were installed on the gas outlet pipe of SCR reactor 8.

[0038] CEMS12 is a device that can continuously monitor the concentration and total emissions of gaseous pollutants and particulate matter emitted from air pollution sources and transmit the information to the competent authorities in real time. It is known as an "automatic flue gas monitoring system", also called a "continuous emission monitoring system for flue gas" or "online flue gas monitoring system".

[0039] The CEMS12 system comprises a gaseous pollutant monitoring subsystem, a particulate matter monitoring subsystem, a flue gas parameter monitoring subsystem, and a data acquisition, processing, and communication subsystem. The gaseous pollutant monitoring subsystem is primarily used to monitor gaseous pollutants SO2 and NO. X The system includes several subsystems: a particulate matter monitoring subsystem and a data acquisition and communication subsystem. The particulate matter monitoring subsystem primarily monitors the concentration and total emissions of smoke and dust. The flue gas parameter monitoring subsystem measures flue gas velocity, temperature, pressure, oxygen content, and humidity, used for total emission calculation and concentration conversion. The data acquisition, processing, and communication subsystem consists of a data acquisition unit and a computer system. It collects various parameters in real time, generates dry-basis, wet-basis, and converted concentrations for each concentration value, generates daily, monthly, and annual cumulative emissions, compensates for lost data, and transmits reports to the relevant authorities in real time. Smoke and dust testing has evolved from cross-flue opacity dust meters and beta-ray dust meters to insertion-type backscattering infrared or laser dust meters, as well as forward-scattering, side-scattering, and electrostatic dust meters. Based on different sampling methods, CEMS12 can be mainly divided into three technologies: direct measurement, extraction measurement, and remote sensing measurement.

[0040] The ammonia slip detector 13 uses a high-temperature extraction-type online ammonia slip analyzer, which can monitor the NH3 concentration in flue gas online.

[0041] The high-temperature extraction-type online ammonia escape analyzer adopts a full-process 280℃ high-temperature extraction design to avoid sample gas condensation and adsorption. Equipped with distributed detection capabilities, it can achieve multi-point NH3 concentration monitoring in the SCR unit's outlet flue. Combined with high-flow-rate sampling, it achieves a response time of ≤20 seconds. The device integrates zero-drift infrared modulated laser technology, eliminating the need for frequent calibration and reducing maintenance requirements. The probe operates in temperatures ranging from 0-500℃ and is equipped with RS485 and 4-20mA output interfaces.

[0042] The denitrification component is further optimized by including a flow equalization plate 10, with a catalyst 11 installed at the outlet end of the flow equalization plate 10. Both the flow equalization plate 10 and the catalyst 11 are installed inside the SCR reactor 8.

[0043] To further optimize the scheme, catalyst 11 adopts a rare earth catalyst.

[0044] The flow equalization plate 10 can equalize the flow of gas in the SCR reactor 8, so that the gas can enter the catalyst 11 for denitrification after the flow velocity in each zone of the cross section is the same.

[0045] By using multiple denitrification components to denitrify the gas inside the SCR reactor 8, stacked denitrification is achieved.

[0046] To further optimize the design, the inlet pipe of SCR reactor 8 is connected to the outlet of the sulfuric acid process gas self-heating exchanger. This allows the sulfuric acid process gas to enter SCR reactor 8 through the outlet of the sulfuric acid process gas self-heating exchanger.

[0047] To further optimize the design, the outlet pipe of SCR reactor 8 is connected to the inlet of the sulfur dioxide catalytic converter. This ensures that the denitrified flue gas can be effectively delivered to the sulfur dioxide catalytic converter.

[0048] A method for using an SCR denitrification device for sulfuric acid process flue gas, the specific steps of which are as follows:

[0049] Liquid ammonia in cylinder 1 is heated and vaporized into ammonia gas, which is then sent to ammonia buffer tank 3. The ammonia gas is precisely regulated by linear flow regulating valve 4 and sent to ammonia-air mixer 6, where it is mixed with compressed air from instrument compressed air buffer tank 5. The mixture is then sent through pipeline to ammonia injection grid 7 for spraying, where it is first mixed with sulfuric acid process flue gas from the heat exchanger. It then enters ammonia-flue gas mixer 9 before SCR reactor 8 for a second mixing, achieving a uniform ammonia-nitrogen ratio in each zone. The mixture then passes through flow equalization plate 10 for the first flow equalization, ensuring the same flow velocity in each zone within the cross section. It then enters catalyst 11 for the first denitrification. After denitrification, it passes through another flow equalization plate 10 for the second flow equalization, and then enters the next catalyst 11 for the second denitrification. After denitrification, the mixture is discharged through the flue and sent to sulfur dioxide catalytic converter.

[0050] The SCR denitrification reaction equation is as follows:

[0051] 4NO + 4NH3 + O2 → 4N2 + 6H2O

[0052] 2NO2 + 4NH3 + O2 → 3N2 + 6H2O

[0053] Example 2

[0054] The sulfuric acid process flue gas SCR denitrification device of this invention is applied to the sulfuric acid process flue gas produced by the incineration of a certain alkylation waste acid. Its flue gas parameters are as follows:

[0055]

[0056]

[0057] Compared to flue gas from thermal power plants, the volume of waste sulfuric acid pyrolysis flue gas is very small, but the concentration of acid mist and sulfur dioxide is very high. The unit operates under positive pressure, and the NO at the clean flue gas outlet is very low. X The concentration is low, and the actual oxygen content differs greatly from the baseline oxygen content.

[0058] The main equipment specifications are as follows:

[0059]

[0060]

[0061] In practice, the sulfuric acid flue gas SCR denitrification device of the present invention can reduce the nitrogen oxides (NOx) in the final emission tail gas of sulfuric acid. X Clean flue gas emissions reach 15 mg / Nm 3 (Standard) or below, ammonia slip is less than 1 mg / Nm³. 3 (Standard) ultra-clean emission requirements, and improve the quality of sulfuric acid products.

[0062] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0063] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A sulfuric acid process flue gas SCR denitrification device, characterized in that: The system includes an SCR reactor (8), wherein the inlet pipe of the SCR reactor (8) is provided with a gas supply component for supplying ammonia, and the outlet pipe of the SCR reactor (8) is provided with a detection component for monitoring gas concentration. An ammonia fume mixer (9) is installed in one end of the SCR reactor (8) near the inlet pipe of the SCR reactor (8), and multiple denitrification components are installed in one end of the SCR reactor (8) near the outlet pipe of the SCR reactor (8).

2. The sulfuric acid process flue gas SCR denitrification device according to claim 1, characterized in that: The gas supply assembly includes an electric heating constant temperature box (2), in which a liquid ammonia cylinder (1) is installed. The outlet of the liquid ammonia cylinder (1) is connected to an ammonia buffer tank (3). The ammonia buffer tank (3) is connected to an inlet of an ammonia-air mixer (6). The outlet of the ammonia-air mixer (6) is connected to an ammonia spray grid (7). The ammonia spray grid (7) is located in the inlet pipe of the SCR reactor (8).

3. The sulfuric acid process flue gas SCR denitrification device according to claim 2, characterized in that: The other air inlet of the ammonia-air mixer (6) is connected to an instrument compressed air buffer tank (5).

4. The sulfuric acid process flue gas SCR denitrification device according to claim 2, characterized in that: A linear flow regulating valve (4) is installed on the pipeline connecting the ammonia buffer tank (3) and the ammonia air mixer (6).

5. The sulfuric acid process flue gas SCR denitrification device according to claim 1, characterized in that: The detection components include a CEMS (12) and an ammonia slip detector (13), which are installed on the outlet pipe of the SCR reactor (8).

6. The sulfuric acid process flue gas SCR denitrification device according to claim 1, characterized in that: The denitrification assembly includes a flow equalization plate (10), and a catalyst (11) is provided at the outlet end of the flow equalization plate (10). Both the flow equalization plate (10) and the catalyst (11) are installed inside the SCR reactor (8).

7. The sulfuric acid process flue gas SCR denitrification device according to claim 6, characterized in that: The catalyst (11) is a rare earth catalyst.

8. The sulfuric acid process flue gas SCR denitrification device according to claim 1, characterized in that: The inlet pipe of the SCR reactor (8) is connected to the outlet of the sulfuric acid process gas self-heating exchanger.

9. The sulfuric acid process flue gas SCR denitrification device according to claim 1, characterized in that: The outlet pipe of the SCR reactor (8) is connected to the inlet of the sulfur dioxide catalyst converter.

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