Industrial flue gas denitration treatment zero emission device

Abstract

The utility model discloses an industrial flue gas denitration treatment zero-emission device, which relates to the technical field of industrial flue gas urea hydrolysis denitration water treatment, and comprises a hydrolyzer, the hydrolyzer is provided with a liquid inlet pipeline, a sewage discharge pipeline, a pressurization pipeline, a pressure relief pipeline and an ammonia conveying pipeline, the inner wall of the hydrolyzer is fixedly provided with a tube bundle, an inlet of the tube bundle is connected with a steam valve, and the steam valve is connected with a water outlet of the tube bundle. The tube bundle outlet is connected with a drain valve; according to the application, through the arrangement of the pressurization pipeline, the sewage discharge pipeline, the pressure relief pipeline and the dilution water pipeline, unreacted urea solution wastewater in the hydrolyzer is ensured to be pumped into the urea solution storage tank through pressurization, so that cyclic utilization is realized; when overpressure occurs, the ammonia gas mixer in the hydrolyzer can be transferred into the urea solution storage tank, and dilution water is used for dilution and spraying, so that the ammonia gas mixed waste gas can be effectively blended into the urea solution storage tank, the recycling of waste water and waste gas is realized, and the goal of zero emission is achieved. Compared with a traditional process, the device is simpler in structure and higher in practicability.

Description

Technical Field

[0001] The utility model relates to the technical field of industrial flue gas urea hydrolysis denitrification water treatment, in particular to an industrial flue gas denitrification treatment zero-emission device. Background Art

[0002] Nitrogen oxides (NOx) in industrial flue gas are one of the main sources of environmental problems such as acid rain and photochemical smog. Through SCR denitrification treatment, the emission of nitrogen oxides can be reduced, thereby reducing atmospheric acidification and the formation of photochemical smog, and improving air quality. SCR denitrification technology mainly uses urea as a reducing agent. Urea aqueous solution can provide efficient denitrification performance in the SCR denitrification process.

[0003] Urea particles need to be hydrolyzed first, and the urea in the aqueous solution can react with nitrogen oxides (NOx) through the action of a catalyst to generate ammonia. These ammonia react with NOx in the flue gas and convert it into harmless nitrogen and water. However, since the intermediate product of the hydrolysis reaction, ammonium carbamate, is highly corrosive, and the hydrolysis temperature is strictly required, the hydrolysis process is prone to urea crystallization and hardening when the temperature is too high or too low during operation, so the hydrolyzer has a high failure rate, is prone to corrosion and leakage during operation, and is often switched for maintenance and accidental discharge during operation. When the hydrolyzer is shut down, the solution and mixed gas in the hydrolyzer must be purged and emptied with nitrogen, otherwise it will cause crystallization and hardening in the hydrolyzer. At the same time, since the mixture of mixed ammonia and urea solution has a strong pungent and irritating odor and corrosive hazard, it is often discharged into the wastewater pool. Even if spray dilution is used, it often causes the spread of fog in the hydrolysis workshop, which makes the operator and maintenance personnel unbearable, and the ammonia overflow is dangerous, all of which limit the application of urea hydrolysis denitrification. Therefore, a zero-emission device for industrial flue gas denitrification treatment is proposed. Utility Model Content

[0004] In order to solve the above problems, that is, to solve the problems raised by the above background technology, the utility model proposes a zero-emission device for industrial flue gas denitrification treatment, which includes a hydrolyzer, the hydrolyzer is equipped with a liquid inlet pipeline and a sewage pipeline, the liquid inlet pipeline is provided with a urea solution regulating valve, the sewage pipeline is provided with a sewage valve, the hydrolyzer is equipped with a pressurizing pipeline, a pressure relief pipeline and an ammonia delivery pipeline, the pressurizing pipeline is provided with a pressurizing gas valve, the pressure relief pipeline is provided with a safety pressure relief valve, the ammonia delivery pipeline is provided with an ammonia production valve, the inner wall of the hydrolyzer is fixedly installed with a tube bundle, the inlet of the tube bundle is connected to a steam valve, and the outlet of the tube bundle is connected to a steam trap;

[0005] The outlet end of the pressure relief pipeline is connected to the top of the urea solution storage tank, and the end of the pressure relief pipeline close to the urea solution storage tank is also connected to a dilution water pipeline, and a dilution water valve is provided on the dilution water pipeline. The outlet end of the sewage pipeline is connected to the pressure relief pipeline, and the outlet end of the steam trap is connected to the steam trap tank, the steam trap pump and the urea dissolution tank in sequence.

[0006] The utility model is further configured as follows: a spray pipe is installed at the inlet end of the urea solution storage tank.

[0007] The utility model is further configured as follows: the steam valve inputs 200-250° C. saturated steam.

[0008] The utility model is further configured as follows: the liquid inlet pipeline and the sewage discharge pipeline are both located at the bottom of the hydrolyzer, and the pressurizing pipeline, the pressure relief pipeline and the ammonia delivery pipeline are all located at the top of the hydrolyzer.

[0009] The beneficial technical effects of the utility model are as follows: by adopting a pressurized pipeline and a sewage pipeline, and with the help of compressed air pressure, when the hydrolyzer encounters an accidental discharge or is shut down for maintenance, its internal pressure will be reduced, and the pressurized air valve will be opened for pressurization at this time to ensure that the unreacted urea solution wastewater in the hydrolyzer is pumped into the urea solution storage tank for recycling. In addition, we have also set up a pressure relief pipeline and a dilution water pipeline. When the hydrolyzer is overpressured during operation, the ammonia mixer in the hydrolyzer can be transferred to the urea solution storage tank, and diluted and sprayed with dilution water, so that the ammonia mixed waste gas can be effectively integrated into the urea solution storage tank, realizing the recycling of wastewater and waste gas, thereby achieving the goal of zero emissions. Compared with traditional processes, this device is not only simpler in structure, but also more practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 Shown is a schematic diagram of the overall structure of the utility model.

[0011] Figure numerals: 1. hydrolyzer, 2. urea solution regulating valve, 3. drain valve, 4. steam trap, 5. pressurized air valve, 6. safety pressure relief valve, 7. ammonia production valve, 8. steam valve, 9. dilution water valve, 10. urea solution storage tank, 11. steam trap tank, 12. steam trap pump, 13. urea dissolution tank. DETAILED DESCRIPTION

[0012] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0013] The utility model proposes a zero-emission device for denitration of industrial flue gas, comprising a hydrolyzer 1, wherein the hydrolyzer 1 is provided with a liquid inlet pipeline and a sewage pipeline, wherein a urea solution regulating valve 2 is provided on the liquid inlet pipeline, granular urea is preliminarily dissolved into a urea solution of 50% mass concentration with desalted water, and a delivery pump is used to allow the urea solution to enter the hydrolyzer 1 via the liquid inlet pipeline, wherein a sewage valve 3 is provided on the sewage pipeline, wherein the hydrolyzer 1 is provided with a pressurizing pipeline, a pressure relief pipeline and an ammonia delivery pipeline, wherein a pressurizing gas valve 5 is provided on the pressurizing pipeline, a safety pressure relief valve 6 is provided on the pressure relief pipeline, and an ammonia production valve 7 is provided on the ammonia delivery pipeline, wherein a tube bundle is fixedly installed on the inner wall of the hydrolyzer 1, wherein a steam valve 8 is connected to the inlet of the tube bundle, and a steam trap 4 is connected to the outlet of the tube bundle;

[0014] The outlet end of the pressure relief pipeline is connected to the top of the urea solution storage tank 10, and the end of the pressure relief pipeline close to the urea solution storage tank 10 is also connected to a dilution water pipeline, and a dilution water valve 9 is provided on the dilution water pipeline. The outlet end of the sewage pipeline is connected to the pressure relief pipeline, and the outlet end of the steam trap 4 is connected to the steam trap box 11, the steam trap pump 12 and the urea dissolution tank 13 in sequence.

[0015] The hydrolyzer 1 is provided with a pressurized pipeline and a pressurized gas valve 5, and a steam valve 8 inputs saturated steam at 200-250°C.

[0016] A spray pipe is installed at the inlet end of the urea solution storage tank 10 .

[0017] The liquid inlet pipeline and the sewage discharge pipeline are both located at the bottom of the hydrolyzer 1 , and the pressurizing pipeline, the pressure relief pipeline and the ammonia delivery pipeline are all located at the top of the hydrolyzer 1 .

[0018] Working process: The hydrolyzer 1 uses steam (200-250℃ saturated steam) as the hydrolysis heat source. The urea solution enters the hydrolyzer 1 through the bottom urea solution regulating valve 2. The general liquid level is 500-800mm. The steam valve 8 is opened to transport steam into the tube bundle in the hydrolyzer, and indirectly heats and hydrolyzes with the urea solution outside the tube bundle to produce ammonia. The produced ammonia is transported to the furnace area ammonia air mixer through the ammonia production valve 7 on the ammonia pipeline, and mixed with the diluted air heated by the dilution fan to form ammonia gas with a concentration below 5%. It is sprayed into the SCR reactor through the ammonia injection system for denitrification reaction, and then the industrial flue gas is treated. The drain flowing out of the tube bundle outlet inside the hydrolyzer 1 enters the drain box 11 through the drain valve 4, and is pumped to the urea dissolution tank 13 by the drain pump 12 for recycling and reuse for subsequent urea heating and dissolution.

[0019] The waste water generated by the hydrolyzer 1 is transported to the top of the urea solution storage tank 10 through the drain valve 3 of the drain pipeline, and is sprayed into the urea solution storage tank 10 through the spray pipe; the waste gas generated by the hydrolyzer 1 is transported to the top of the urea solution storage tank 10 through the safety pressure relief valve 6 on the pressure relief pipeline, and is sprayed into the urea solution storage tank 10 through the spray pipe.

[0020] Since the internal pressure of the hydrolyzer 1 is about 0.45-0.5MPa during operation, the internal pressure of the hydrolyzer decreases when the accident discharge and maintenance shutdown occur. The present application sets a pressurized pipeline on the upper part of the hydrolyzer, and uses the compressed air above 0.5MPa in the plant area to open the pressurized air valve 5 for pressurization, and the urea solution wastewater that has not been completely reacted in the hydrolyzer is all pumped into the urea solution storage tank 10 for recycling by opening the sewage valve 3. When the hydrolyzer is overpressured, the safety pressure relief valve 6 is opened to pump the remaining ammonia mixed gas in the hydrolyzer into the urea solution storage tank 10, and the dilution water valve 9 is opened to dilute the waste gas through the dilution water pipeline, and then sprayed into the urea solution storage tank 10 for recycling through the spray pipe bundle, so as to avoid the waste gas overflow and cause pungent odor.

[0021] The valves of the entire device are automatic valves that operate automatically through DCS interlocking control, which completely solves the problem that traditional devices directly discharge wastewater and exhaust gas into the wastewater pool, causing safety risks of excessive ammonia concentration in the workshop and toxic odor.

[0022] The present application adopts a pressurized pipeline and a sewage pipeline, and utilizes compressed air pressure. When the hydrolyzer is accidentally discharged or shut down for maintenance, its internal pressure is reduced and the pressurized air valve is opened to pressurize the unreacted urea solution wastewater in the hydrolyzer, and the unreacted urea solution wastewater in the hydrolyzer is pumped into the urea solution storage tank 10 for recycling. Compared with traditional process devices, it is simple and practical.

[0023] In addition, a pressure relief pipeline and a dilution water pipeline are used. When the hydrolyzer is running at overpressure, the ammonia mixer in the hydrolyzer is pumped into the urea solution storage tank 10, and the dilution water is used for dilution spraying, so that the ammonia mixed gas exhaust gas is integrated into the urea solution storage tank 10 for recycling, and the recycling of wastewater and exhaust gas is achieved with zero emission.

[0024] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0025] So far, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. An industrial flue gas denitrification treatment zero emission device, comprising a hydrolyzer (1), wherein the hydrolyzer (1) is equipped with a liquid inlet pipeline and a sewage discharge pipeline, wherein the liquid inlet pipeline is provided with a urea solution regulating valve (2), and the sewage discharge pipeline is provided with a sewage discharge valve (3), characterized in that: The hydrolyzer (1) is equipped with a pressurizing pipeline, a pressure relief pipeline and an ammonia delivery pipeline, the pressurizing pipeline is provided with a pressurizing gas valve (5), the pressure relief pipeline is provided with a safety pressure relief valve (6), the ammonia delivery pipeline is provided with an ammonia production valve (7), a tube bundle is fixedly installed on the inner wall of the hydrolyzer (1), the inlet of the tube bundle is connected to a steam valve (8), and the outlet of the tube bundle is connected to a steam trap (4); The outlet end of the pressure relief pipeline is connected to the top of the urea solution storage tank (10), and one end of the pressure relief pipeline close to the urea solution storage tank (10) is also connected to a dilution water pipeline, and a dilution water valve (9) is provided on the dilution water pipeline. The outlet end of the sewage pipeline is connected to the pressure relief pipeline, and the outlet end of the steam trap (4) is connected to a steam trap tank (11), a steam trap pump (12) and a urea dissolution tank (13) in sequence.

2. The zero-emission device for denitrification of industrial flue gas according to claim 1, characterized in that: A spray pipe is installed at the inlet end of the urea solution storage tank (10).

3. The zero-emission device for denitrification of industrial flue gas according to claim 1, characterized in that: The steam valve (8) inputs saturated steam at 200-250°C.

4. The zero-emission device for denitrification of industrial flue gas according to claim 1, characterized in that: The liquid inlet pipeline and the sewage discharge pipeline are both located at the bottom of the hydrolyzer (1), and the pressurization pipeline, the pressure relief pipeline and the ammonia delivery pipeline are all located at the top of the hydrolyzer (1).

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