CN207970687U - Intermittent cyclic fluid bed and utilize its flue gas purification system - Google Patents

Abstract

The utility model provides an intermittent circulating fluidized bed and a flue gas purification system using it. The intermittent circulating fluidized bed includes an intermittent reactor, a feed pipe, a metal filter and a fan. The intermittent reactor is a closed columnar reaction device; the flue gas purification system includes desulfurization and denitration agent metering and feeding system, intermittent circulating fluidized bed, gas-solid separation equipment and discharge equipment. The purification system desulfurizes and denitrates the flue gas simultaneously through the intermittent circulating fluidized bed, which reduces the cost of flue gas desulfurization and denitrification.

Description

Intermittent circulating fluidized bed and flue gas purification system using it

technical field

The utility model belongs to the field of flue gas purification, and relates to an intermittent circulating fluidized bed and a flue gas purification system using it, in particular to sintering flue gas and coal burning flue gas for the iron and steel industry.

Background technique

With the development of the economy, especially the rapid growth of the economy dominated by energy consumption, a large number of factories emit flue gas containing particulate matter, SO ₂ , NO _X , heavy metals and other pollutants, causing acid rain, smog and photochemical smog, which is harmful to people, animals and plants cause great harm. In order to meet people's demand for environmental protection and accelerate the process of energy production and consumption revolution, the country has gradually raised the emission standards for industrial smoke. In 2016, the "Emission Standards of Air Pollutants for Iron and Steel Sintering and Pelletizing Industry" announced the revision of emission standards, and adjusted the emission limits of sulfur dioxide and nitrogen oxides again. Control industrial flue gas, and tighten special emission limit requirements. Regarding the "Emission Standards of Air Pollutants for Thermal Power" (GB13223-2011), the ultra-low emission standards for coal-fired boilers are issued, which is the ultra-low emission limits for coal-fired units. No more than 5mg/m ³ , 35mg/m ³ , 50mg/m ³ respectively. Therefore, it is imminent to simultaneously control the emissions of SO ₂ and NO _x .

Coal-fired flue gas and sintering flue gas are the main sources of industrial waste gas. Due to historical reasons, most of the pollutant removal equipment currently used in my country's coal-fired power plants are flue gas purification equipment sequences with a single function and used in series formed in different periods. , the commonly used method is limestone-gypsum desulfurization + SCR denitrification + electric (bag) dust removal. Due to the current situation of high ash, high sulfur and large flue gas treatment in domestic coal combustion, the original technology cannot meet the ultra-low emission requirements . The iron and steel industry has developed rapidly in my country, but its sintering flue gas pollution has become an important factor restricting the sustainable development of my country's metallurgical industry. The sintering flue gas produced in the iron and steel industry has the characteristics of low discharge temperature, large fluctuation range, high moisture content, complex chemical components, and wide particle size distribution. At present, there is still a lack of simple and effective comprehensive treatment for simultaneous desulfurization and denitrification of flue gas method. In addition to the control of dust and SO ₂ in the flue gas, traditional treatment methods have not effectively controlled harmful substances such as NO _x and dioxins. Therefore, the integrated control of flue gas multi-pollutants has become an inevitable choice for my country's environmental protection and sustainable development of the iron and steel metallurgical industry.

At present, the main goal of the integrated control of flue gas multi-pollutants in the iron and steel industry is to desulfurize and denitrify sintering flue gas, mainly through the combination of traditional desulfurization technology and flue gas denitrification technology. In the traditional desulfurization technology, calcium-based particles are mostly used as desulfurizers, which have the advantages of good desulfurization effect (the desulfurization efficiency is over 95%) and stable operation. _NOx and other issues. Flue gas denitrification technologies mainly include two types: selective catalytic reduction (SCR) and non-selective catalytic reduction (SNCR). The temperature window required by SNCR is 850-1050°C. Generally, another heating device is required to heat the flue gas to this temperature window. The energy consumption is high and the efficiency is low. Therefore, the denitrification system is mostly based on SCR technology.

If the above-mentioned traditional desulfurization technology is combined with the flue gas denitrification technology for synergistic desulfurization and denitrification, although the purpose of desulfurization and denitrification can be achieved, it requires the coordination of multiple sets of equipment, and there are problems such as large total investment, complicated process, and large floor area. In addition, sintering flue gas has the characteristics of high sulfur dioxide content and low temperature (100-180°C). If SCR technology is used, the one-time investment is relatively high, and the denitrification efficiency of one layer of SCR catalyst is only about 50%. % and above, two layers of SCR catalysts need to be arranged, but it is difficult to meet the requirement that the reaction temperature of SCR catalysts is usually 300-450°C under this condition, so the flue gas in the denitrification process needs to be heated. At the same time, ammonium sulfate and ammonium bisulfate are likely to be produced during the denitrification process using SCR technology, which will block the SCR catalyst and poison the SCR catalyst, which will greatly increase the related costs. Therefore, it is very important to design and develop a set of technologies suitable for simultaneous desulfurization and denitrification of sintering flue gas in the iron and steel industry, and to reduce the cost of purification and treatment of sintering flue gas in the iron and steel industry.

Utility model content

In order to overcome the problems in the above-mentioned background technology, the utility model provides an intermittent circulating fluidized bed and a flue gas purification system using it. The purification system simultaneously desulfurizes and denitrates the flue gas through the intermittent circulating fluidized bed, reducing the flue gas desulfurization and denitrification. cost.

A kind of intermittent circulating fluidized bed, comprises batch reactor, feed pipe, metal filter and blower fan, and described batch reactor is a closed cylindrical reactor, and one end of described feed pipe extends from the top of batch reactor to The bottom end of the batch reactor is connected with the inside of the batch reactor, and the other end of the feed pipe is the feed port. filter, the inlet end of the metal filter communicates with the inside of the batch reactor, the outlet end of the metal filter is connected to the inlet end of the fan arranged outside the batch reactor through a pipeline, and the outlet end of the fan is connected to the batch reactor The circulation air inlet provided on the top of the batch reactor is connected by pipes, and the top of the batch reactor is also provided with a purified flue gas outlet.

Usually, the purified flue gas outlet at the top of the batch reactor needs to communicate with the air inlet of the post-processing equipment through a pipeline. In order to reduce costs, no additional second air blower is added, and the following scheme is preferred:

The outlet end of the metal filter is connected to one end of the first circulation pipeline, the other end of the first circulation pipeline is connected to the inlet end of the fan, the outlet end of the fan is connected to one end of the second circulation pipeline, and the other end of the second circulation pipeline It is connected with the circulation inlet of the batch reactor, the first circulation pipeline is provided with a return valve, the second circulation pipeline is provided with a one-way valve, and the purified flue gas outlet at the top of the batch reactor is connected to the One end of the first air outlet pipe is connected, and the other end of the first air outlet pipe is connected with the first circulation pipeline at the pipeline between the return valve and the blower fan. The first air outlet pipe is provided with a first air outlet valve, and the second circulation pipeline is located at One end of the second air outlet pipe is connected to the pipe between the blower fan and the one-way valve, and the other end of the second air outlet pipe is used as the outlet end of the purified flue gas of the intermittent circulating fluidized bed.

Further, in order to prevent the internal partial pressure from being too high during the flue gas circulation process of the closed reactor, a flow control valve is provided on the second gas outlet pipe.

Further, the bottom end of the gap reactor is provided with a waste discharge pipe and a waste discharge valve corresponding thereto.

The flue gas purification system utilizing the above-mentioned intermittent circulating fluidized bed includes a desulfurization and denitrification agent metering feeding system, an intermittent circulating fluidized bed, gas-solid separation equipment and discharge equipment. The desulfurization and denitrification agent metering feeding system includes a batching device, a metering Feeding equipment and dry powder injection pipe, the discharge end of the batcher is connected to the feed end of the metering feeding equipment through a pipeline, and the discharge end of the metering feeding equipment is connected to the feed port of the dry powder injection pipe through a pipeline , the injection port of the dry powder injection pipe is connected to the feed port of the intermittent circulating fluidized bed, and the purified flue gas outlet or gas outlet of the intermittent circulating fluidized bed is connected to the inlet end of the gas-solid separation device through a pipeline, The gas outlet of the gas-solid separation equipment is connected with the discharge equipment.

Preferably, the metering and feeding equipment includes an electronic screw scale, a rotary feeder, a pneumatic conveying pump, and a Roots blower. The discharge end of the scale is connected to the feed end of the rotary feeder, and the pneumatic conveying pump includes an air inlet acceleration port, a dry powder feed port and an accelerated dry powder discharge port, and the discharge end of the rotary feeder is connected to the pneumatic feeder. The dry powder feed port of the conveying pump is connected, the air outlet of the Roots blower is connected with the air inlet acceleration port of the pneumatic conveying pump, and the discharge end of the metering and feeding equipment is the accelerated dry powder discharge port of the pneumatic conveying pump.

Usually, the pneumatic conveying pump is a Venturi feeder, SK powder two-way valve or a bin pump.

Usually, according to the amount of desulfurization and denitrification agent injected, multiple dry powder injection pipes are provided, and the feed ports of the multiple dry powder injection pipes are connected with the accelerated dry powder discharge port of the pneumatic conveying pump in the form of branch pipes.

Preferably, the gas-solid separation equipment is a bag filter.

Generally, the exhaust equipment includes an induced draft fan and a smoke exhaust chimney, the outlet end of the gas-solid separation equipment is connected with the air inlet end of the induced draft fan through a pipeline, and the air outlet end of the induced draft fan is connected with the intake end of the smoke exhaust chimney through a pipeline .

The utility model can be directly installed on the rear end of sintering flue gas or coal-fired flue gas desulfurization treatment equipment, so that the flue gas discharge standard meets relevant regulations.

The utility model has the following beneficial effects:

1. The utility model system organically combines flue gas desulfurization, denitrification and dust removal to form a complete process system, which simplifies the existing technology in which flue gas is independently carried out in each link of desulfurization, denitrification and dust removal, thereby reducing initial investment and operating costs .

2. The utility model system is especially suitable for small and medium-sized flue gas flow treatment, flue gas treatment below 60m ³ /h.

Description of drawings

Fig. 1 is a kind of structure diagram of the intermittent circulating fluidized bed of the utility model.

Fig. 2 is another structural schematic diagram of the intermittent circulating fluidized bed of the present invention.

Fig. 3 is a schematic structural diagram of the flue gas purification system of the present invention.

In the figure, 1 batching device, 1-1 batching valve, 2 electronic screw scale, 3 rotary feeder, 4 Roots fan, 5 pneumatic conveying pump, 6 dry powder injection pipe, 6-1 dry powder injection valve, 7 gas-solid separation Equipment, 8 induced draft fan, 9 exhaust chimney, 13 batch reactor, 13-1 reactor exhaust valve, 14 metal filter, 15 first circulation pipe, 15-1 return valve, 16 second circulation pipe, 16 -1 one-way valve, 17 fan, 18 feed pipe, 19 first air outlet pipe, 19-1 first air outlet valve, 20 second air outlet pipe, 20-1 flow control valve, 21 flue gas inlet pipe.

Detailed ways

Below by embodiment and in conjunction with accompanying drawing, the utility model is further described. It is worth pointing out that the given embodiments can not be interpreted as limiting the scope of protection of the utility model, and some non-essential improvements and adjustments made by those skilled in the art according to the content of the utility model should still belong to the utility model protected range.

Example 1

As shown in Figure 1, the intermittent circulating fluidized bed provided by the present embodiment comprises a batch reactor 13, a feed pipe 18, a metal filter 14 and a fan 17, and the batch reactor 13 is Closed cylindrical reactor, one end of the feed pipe 18 extends from the top of the batch reactor 13 to the bottom end of the batch reactor and communicates with the inside of the batch reactor, the other end of the feed pipe 18 is a feed port, and the feed pipe 18 is located on the side wall outside the batch reactor and is connected with a flue gas inlet pipe 21. The top of the batch reactor 13 is provided with a metal filter 14, and the inlet end of the metal filter 14 communicates with the inside of the batch reactor 13. The air outlet end of the metal filter 14 is connected with one end of the first circulation pipeline 15, and the other end of the first circulation pipeline 15 is connected with the inlet end of the fan 17, and the gas outlet end of the fan 17 is connected with the second circulation pipeline 16 one end, and the second The other end of the circulation pipeline 16 is connected with the circulation air inlet provided on the top of the batch reactor 13, the first circulation pipeline 15 is provided with a return valve 15-1, and the second circulation pipeline 16 is provided with a one-way valve. Valve 16-1, the top of the batch reactor 13 is connected to one end of the first air outlet pipe 19, and the other end of the first air outlet pipe 19 is connected to the first circulation pipe 15 at the pipe between the return valve 15-1 and the fan 17 , the first air outlet pipe 19 is provided with a first air outlet valve 19-1, and the second circulation pipe 16 is located on the pipeline between the fan 17 and the one-way valve 16-1 and is connected with one end of the second air outlet pipe 20, the second The other end of the outlet pipe 20 is used as the outlet end of the purified flue gas of the intermittent circulating fluidized bed.

The bottom of the batch reactor 13 is provided with a reactor drain valve 13-1.

Example 2

As shown in Figure 2, the intermittent circulating fluidized bed provided by the present embodiment includes a batch reactor 13, a feed pipe 18, a metal filter 14 and a fan 17, and the batch reactor 13 is Closed cylindrical reactor, one end of the feed pipe 18 extends from the top of the batch reactor 13 to the bottom end of the batch reactor and communicates with the inside of the batch reactor, the other end of the feed pipe 18 is a feed port, and the feed pipe 18 is located on the side wall outside the batch reactor and is connected with a flue gas inlet pipe 21. The top of the batch reactor 13 is provided with a metal filter 14, and the inlet end of the metal filter 14 communicates with the inside of the batch reactor 13. The air outlet end of the metal filter 14 is connected with one end of the first circulation pipeline 15, and the other end of the first circulation pipeline 15 is connected with the inlet end of the fan 17, and the gas outlet end of the fan 17 is connected with the second circulation pipeline 16 one end, and the second The other end of the circulation pipeline 16 is connected with the circulation air inlet provided on the top of the batch reactor 13, the first circulation pipeline 15 is provided with a return valve 15-1, and the second circulation pipeline 16 is provided with a one-way valve. Valve 16-1, the top of the batch reactor 13 is connected to one end of the first air outlet pipe 19, and the other end of the first air outlet pipe 19 is connected to the first circulation pipe 15 at the pipe between the return valve 15-1 and the fan 17 , the first air outlet pipe 19 is provided with a first air outlet valve 19-1, and the second circulation pipe 16 is located on the pipeline between the fan 17 and the one-way valve 16-1 and is connected with one end of the second air outlet pipe 20, the second The other end of the outlet pipe 20 is used as the outlet end of the purified flue gas of the intermittent circulating fluidized bed.

A flow control valve 20-1 is provided on the second outlet pipe 20, and a reactor exhaust valve 13-1 is provided at the bottom of the batch reactor 13.

Example 3

As shown in Figure 3, the present embodiment provides a flue gas purification system utilizing the intermittent circulating fluidized bed of Embodiment 1, including a desulfurization and denitrification agent metering and feeding system, an intermittent circulating fluidized bed, gas-solid separation equipment 7 and discharge equipment, all of which The desulfurization and denitration agent metering and feeding system includes a batcher 1, metering and feeding equipment and a dry powder injection pipe 6, and the metering and feeding equipment includes an electronic screw scale 2, a rotary feeder 3, a pneumatic conveying pump 5, and a Roots blower 4 , the pneumatic conveying pump 5 includes an air inlet acceleration port, a dry powder feed port and an accelerated dry powder discharge port, and the discharge equipment includes an induced draft fan 8 and a smoke exhaust chimney 9;

The discharge end of the batcher 1 is connected to the feed end of the electronic screw scale 2 through a pipeline, and is controlled by a batching valve 1-1, and the discharge end of the electronic screw scale 2 is connected to the feed end of the rotary feeder 3. The material end is connected, the discharge end of the rotary feeder 3 is connected with the dry powder feed port of the pneumatic conveying pump 5 through a pipeline, and the air outlet of the Roots blower 4 is connected with the air inlet acceleration port of the pneumatic conveying pump 5 through a pipeline, The accelerated dry powder discharge port of the pneumatic conveying pump 5 is connected with the feed port of the dry powder injection pipe 6 through a pipeline, and is controlled by the dry powder injection valve 6-1. The injection port of the dry powder injection pipe 6 is connected with the feed pipe 18 The feed port connection;

The gas-solid separation device 7 is a bag filter, the air inlet of the gas-solid separation device 7 is connected to the purified flue gas outlet of the second outlet pipe 20, and the gas outlet of the gas-solid separation device 7 is connected to the inlet of the induced draft fan 8. The air end is connected through a pipeline, the outlet end of the induced draft fan 8 is connected with the intake end of the smoke exhaust chimney 9 through a pipeline, and the flue gas after desulfurization and denitrification is discharged through the smoke exhaust chimney.

Claims (10)

1. a kind of intermittent cyclic fluid bed, it is characterised in that including batch reactor (13), feed pipe (18), metallic filter (14) and wind turbine (17), the batch reactor (13) are closed cylindricality reactor, and described feed pipe (18) one end is from intermittently Reactor top is stretched to inside batch reactor inner bottom and batch reactor and is connected to, and feed pipe (18) other end is charging Mouthful, feed pipe (18) is located at the side wall outside batch reactor and is passed through mouth equipped with flue gas, and batch reactor (13) inner tip is set There is metallic filter (14), is connected to inside the inlet end and batch reactor of the metallic filter (14), metallic filter (14) outlet side is connect with wind turbine (17) inlet end being set to outside batch reactor by pipeline, and wind turbine (17) go out Gas end is connect with the cycle air inlet that batch reactor top is equipped with by pipeline, and batch reactor (13) top is additionally provided with Purifying smoke gas outlet.

2. intermittent cyclic fluid bed according to claim 1, it is characterised in that the outlet side of the metallic filter (14) with First circulation pipeline (15) one end connects, and the other end of first circulation pipeline (15) is connect with the inlet end of wind turbine (17), wind turbine (17) outlet side is connect with second circulation pipeline (16) one end, the other end of second circulation pipeline (16) and batch reactor Air inlet connection is recycled, the first circulation pipeline (15) is equipped with material returning valve (15-1), on the second circulation pipeline (16) Equipped with check valve (16-1), purifying smoke gas outlet and the first escape pipe (19) one end on batch reactor (13) top connect It connecing, the first escape pipe (19) other end and first circulation pipeline connect at the pipeline between material returning valve and wind turbine, and described One escape pipe (19) is equipped with the first air outlet valve (19-1), pipeline of the second circulation pipeline (16) between wind turbine and check valve On be connected with the second escape pipe (20) one end, the second escape pipe (20) other end goes out as the purifying smoke of intermittent cyclic fluid bed Gas end.

3. intermittent cyclic fluid bed according to claim 2, it is characterised in that second escape pipe (20) is equipped with flow Control valve (20-1).

4. according to any one of the claim 1-3 intermittent cyclic fluid beds, it is characterised in that batch reactor (13) bottom End is equipped with waste pipe and corresponding waste valve.

5. utilizing the flue gas purification system of any one of the claim 1-4 intermittent cyclic fluid beds, it is characterised in that including de- Sulphur denitrfying agent dosing system, intermittent cyclic fluid bed, gas-solid separation equipment (7) and exhaust apparatus, the desulfurization denitrification agent Dosing system includes measurer (1), metering feeding device and dry powder injection pipe (6), the discharge end of the measurer (1) with The feed end of metering feeding device is connected by pipeline, discharge end and the dry powder injection pipe (6) of the metering feeding device into Material mouth is connected by pipeline, and the jet port of the dry powder injection pipe (6) is connect with the feed inlet of intermittent cyclic fluid bed, between described It has a rest the purifying smoke gas outlet of recirculating fluidized bed or outlet side is connect with the inlet end of gas-solid separation equipment (7) by pipeline, gas Gu the outlet side of separation equipment (7) is connect with exhaust apparatus.

6. flue gas purification system according to claim 5, it is characterised in that the metering feeding device includes that electron helical claims (2), the feed end of rotary feeder (3), Pneumatic conveying pump (5), roots blower (4), the metering feeding device is electronics spiral shell Rotation claims the feed end of (2), the electron helical that the discharge end of (2) is claimed to be connect with the feed end of rotary feeder (3), the strength Delivery pump (5) includes that air inlet accelerates mouth, dry-coal feeding mouth and accelerates dry powder discharge port, the discharge end of the rotary feeder (3) It is connect with the dry-coal feeding mouth of Pneumatic conveying pump (5), the air inlet of the air outlet and Pneumatic conveying pump (5) of the roots blower (4) Accelerate mouth connection, the discharge end of the metering feeding device is the acceleration dry powder discharge port of Pneumatic conveying pump (5).

7. flue gas purification system according to claim 6, it is characterised in that the Pneumatic conveying pump (5) is fed for venturi Device, SK powders two-way valve or storehouse pump.

8. according to any one of the claim 5-7 flue gas purification systems, it is characterised in that the gas-solid separation equipment (7) is bag Formula deduster.

9. according to any one of the claim 5-7 flue gas purification systems, it is characterised in that the exhaust apparatus includes air-introduced machine (8) and chimney (9), the outlet side of gas-solid separation equipment (7) are connect with the wind inlet end of air-introduced machine (8) by pipeline, air inducing The outlet air end of machine (8) is connect with the inlet end of chimney (9) by pipeline.

10. flue gas purification system according to claim 8, it is characterised in that the exhaust apparatus includes air-introduced machine (8) and row The outlet side of cigarette chimney (9), gas-solid separation equipment (7) is connect with the wind inlet end of air-introduced machine (8) by pipeline, air-introduced machine (8) Outlet air end is connect with the inlet end of chimney (9) by pipeline.