CN205379806U - Electro -catalysis low temperature wet process full load deNOx systems - Google Patents

Abstract

An electrocatalytic low-temperature wet-process full-load denitrification system, which connects the detection and monitoring system, NaCl storage tank, and water replenishment system to the NaCl electrolytic cell respectively, and the NaCl storage tank and water replenishment system replenish NaCl to the NaCl electrolytic cell according to the data of the detection and monitoring system. , the detection and monitoring system monitors, detects, and controls the content of sodium nitrate in the solution. The NaCl electrolytic cell is connected to the denitrification spray absorption tower through a circulating solution pump. The upper part of the electrolytic cell is connected with the NaCl electrolytic cell. The side of the NaCl electrolytic cell has a low-temperature flue gas inlet hole, and the lower part has a concentrated solution outlet. The top of the denitrification spray absorption tower has a purified flue gas outlet hole. This system reduces the demand for construction land, and at the same time greatly reduces the cost of the power plant. At the same time, it eliminates the source of danger and improves the safety of the device operation; makes the flue gas emitted by the power plant meet the national environmental protection requirements at any time; realizes the comprehensive utilization of resources .

Description

An electrocatalytic low temperature wet full load denitrification system

technical field

The utility model patent belongs to the field of prevention and control of atmospheric pollutants in coal-fired power stations, and especially relates to the technology of removing NO _x in coal-fired flue gas by electrocatalysis under low temperature conditions, wherein NO _x represents nitrogen oxidation in coal-fired flue gas various forms of things.

Background technique

The NO _x gas emitted during the coal combustion process is a harmful and difficult to deal with air pollutants. In the "Emission Standard of Air Pollutants for Thermal Power Plants GB13223-2011" issued by China in 2011, it is clearly stipulated that the nitrogen in coal-fired power plants The emission of oxides shall not be higher than 100mg/m ³ . Selective Catalytic Reduction (SCR) technology is widely used in domestic power plants to remove _NOx pollutants. The device is generally installed in front of the air preheater after the economizer, and uses the reducing agent ammonia (NH ₃ ) to act on the metal catalyst Next, selectively react with NO _x to generate N ₂ and H ₂ O. The main limitation of this technology is that the reaction temperature of the catalyst is high. When the load of the unit decreases, the temperature of the flue gas gradually decreases until it is lower than the minimum operating temperature of the catalyst, the activity of the catalyst decreases significantly, and the denitrification efficiency decreases, which cannot meet the environmental protection requirements; at the same time, the SCR system is easy to generate sulfuric acid. Ammonium salts block the pores of the catalyst, causing catalyst poisoning, which also leads to a decrease in efficiency and excessive environmental emissions; and ammonium sulfate salts will block and corrode the downstream air preheater; more importantly, waste metal catalysts are toxic and easily cause secondary pollution , its recovery and disposal is a problem that is difficult to solve now; because the reducing agent generally uses liquid ammonia, its transportation and storage safety hazards are relatively large, and if urea is used to prepare ammonia, the energy waste is serious.

Utility model content

The purpose of this utility model is to provide a safe, economical, pollution-free and effective electrocatalytic low-temperature wet full-load denitrification system. Prepare a certain concentration of NaClO solution by means of electrolysis of table salt, and use the oxidizing property of NaClO to oxidize NO _x into water-soluble nitrate ions, and the generated nitrate ions will further combine with sodium ions to form commercially valuable sodium nitrate (NaNO ₃ ) , The removal of nitrogen oxides and the recovery of NaNO ₃ are finally realized by means of evaporation and crystallization.

In order to achieve the above purpose, the utility model provides an electrocatalytic low-temperature wet full-load denitrification system, which is characterized in that it includes a NaCl electrolytic cell, a denitrification spray absorption tower, a circulating solution pump, a spray device, a detection and monitoring system, and a NaCl storage tank, water replenishment system, concentrated solution delivery pump, NaNO ₃ recovery system, detection and monitoring system, NaCl storage tank, and water replenishment system are respectively connected to the NaCl electrolytic cell, and the NaCl storage tank and water replenishment system replenish the NaCl electrolytic cell according to the data of the detection and monitoring system. NaCl, the detection and monitoring system monitors, detects, and controls the content of sodium nitrate in the solution. The NaCl electrolytic cell is connected to the denitrification spray absorption tower through a circulating solution pump. The top of the NaCl electrolytic cell is connected with the NaCl electrolytic cell. The side of the NaCl electrolytic cell has a low-temperature flue gas inlet hole, and the bottom has a concentrated solution outlet. The top of the denitrification spray absorption tower has a purified flue gas outlet.

Compared with the prior art, this system has the following characteristics:

1. Using NaCl in the NaCl electrolytic cell as the catalyst does not require a separate ammonia zone, which reduces the demand for construction land, and at the same time greatly reduces the cost of the power plant, while eliminating hazards and improving the safety of device operation;

2. After the denitration device is equipped with a desulfurization device, the denitrification reaction temperature is stable, and the denitrification efficiency can be guaranteed to be relatively stable; at the same time, full-load and full-time flue gas denitrification can be realized, so that the flue gas emitted by the power plant can meet the national environmental protection requirements at any time;

3. The generated NaNO ₃ has commercial value, realizes the comprehensive utilization of resources, and reduces the cost of flue gas treatment.

4. The flue gas entering the denitrification system has been purified by dust removal and desulfurization treatment, the reaction environment is good, and the operating life of the device is guaranteed.

5. The main reaction of denitrification adopts denitrification spray absorption tower, which can further reduce the level of smoke and dust emissions, replace wet dust collectors, simplify the power plant flue gas purification system, and save power plant infrastructure and operating costs.

In summary, the denitrification system of the present invention has obvious advantages compared with the traditional denitrification system in terms of denitrification effect, device safety, construction cost, and operation cost.

Description of drawings

Accompanying drawing 1 is a schematic diagram of the utility model system.

detailed description

Referring to Figure 1, the utility model includes a NaCl electrolytic cell 1, a denitrification spray absorption tower 2, a circulating solution pump 3, a spray device 4, a detection and monitoring system 5, a NaCl storage tank 6, a water supply system 7, a detection and monitoring system, a NaCl storage The tank and water supply system are respectively connected to the NaCl electrolytic cell. The NaCl storage tank and the water replenishment system replenish NaCl to the NaCl electrolytic cell according to the data of the detection and monitoring system. The detection and monitoring system monitors, detects, and controls the content of sodium nitrate in the solution. The NaCl electrolytic cell passes through The circulating solution pump is connected with the denitrification spray absorption tower. The denitrification spray absorption tower is equipped with a spray device. The denitrification spray absorption tower is set on the NaCl electrolytic cell and communicates with the NaCl electrolytic cell. The side of the NaCl electrolytic cell has a low-temperature flue gas inlet The hole is connected to the wet desulfurization device, and there is a concentrated solution outlet at the bottom for connecting the NaNO ₃ recovery system 9 through the concentrated solution delivery pump 8. There is a purified flue gas outlet hole on the top of the denitrification spray absorption tower, and the purified flue gas is discharged through the chimney .

Working principle: In the electrolysis device, NaCl is electrolyzed to generate NaClO to obtain a certain concentration of NaClO solution, and then the circulating solution pump is used to send the NaClO solution to the spray layer of the spray device located in the denitrification spray absorption tower, the number of spray layers Depends on smoke composition. After passing through the wet desulfurization device, the low-temperature flue gas adopts a countercurrent method, and flows through the denitrification system at a certain flow rate from bottom to top to realize the wet removal of nitrogen oxides. The denitrified solution falls back to the electrolysis device at the bottom, and the purified flue gas enters the chimney and is discharged. After NaClO oxidizes _NOx , it is reduced to NaCl, which is re-electrolyzed in the electrolysis device to generate NaClO, thereby realizing the recycling of NaCl. The detection and monitoring system is used to monitor, detect, and control the content of sodium nitrate in the solution. When the concentration of sodium nitrate reaches a certain value, the solution is discharged and enters the NaNO ₃ recovery system for evaporation and crystallization to obtain solid sodium nitrate. The solution after evaporation and crystallization is sent back to the electrolysis device to realize the recycling of water resources. The NaCl storage tank is put into operation according to the needs of the detection and monitoring control system, and the evaporated water in the system is replenished through the water supply system.

Claims (1)

1. an electro-catalysis low temperature wet method full load denitrating system, it is characterised in that: include NaCl electrolysis bath, denitration spray absorber, circulation solution pump, spray equipment, Inspection and monitoring system, NaCl storage tank, water charging system, concentrated solution delivery pump, NaNO₃Recovery system, Inspection and monitoring system, NaCl storage tank, water charging system each connects with NaCl electrolysis bath respectively, NaCl storage tank and water charging system supplement NaCl according to the data of Inspection and monitoring system to NaCl electrolysis bath, Inspection and monitoring system is monitored, detection, control the content of sodium nitrate in solution, NaCl electrolysis bath is connected with denitration spray absorber by circulation solution pump, in denitration spray absorber, spray equipment is set, denitration spray absorber is arranged on above NaCl electrolysis bath and communicates with NaCl electrolysis bath, NaCl electrolysis bath side has low-temperature flue gas air inlet, have concentrated solution outlet below, denitration spray-absorption top of tower has purifying smoke venthole.