CN204816206U - Coke oven flue desulphurization of exhaust gas denitration integrated device - Google Patents

Abstract

The utility model discloses an integrated device for desulfurization and denitrification of coke oven flue waste gas. A flue gas inlet is arranged on the side of a reaction tower, and a desulfurization area, a denitrification area, a denitrification area, and a In the fog zone, the top of the reaction tower is provided with a flue gas outlet; the reaction tower is located below the flue gas inlet as a slurry pool. The desulfurization area is provided with several desulfurization spray heads, and several desulfurization spray heads are connected in parallel on the first circulation pipeline; On the second circulation pipeline; the first circulation pipeline and the second circulation pipeline communicate with the slurry pool and/or the solution pool. The utility model has the advantages of low investment, low energy consumption, simple and reliable system, low operating cost, high utilization rate of on-site resources, high desulfurization and denitrification efficiency, desulfurization efficiency of more than 95%, and denitrification efficiency of more than 80%. It fully complies with the national coking chemical industry pollutant discharge standard.

Description

A coke oven flue exhaust gas desulfurization and denitrification integrated device

Technical field:

The utility model relates to an integrated device for desulfurization and denitrification of coke oven flue waste gas, which belongs to the technical field of coking waste gas treatment.

Background technique:

Coke is a major by-product of coal conversion. It is mainly used in blast furnace ironmaking. It acts as a reducing agent, exothermic agent and material column skeleton. It is an important raw material for the iron and steel industry.

Coke is formed by heating coal in the carbonization chamber of a coke oven under air-isolated conditions and undergoing a series of complex processes of physical changes and chemical reactions. The coke oven gas produced during coke carbonization contains pollutants such as sulfur dioxide and nitrogen oxides, which will generate new pollution in the subsequent use process. These sulfur dioxide and nitrogen oxides are important components of PM2.5 particulate matter, and are also the main cause of acid rain and smog. Its production mechanism is: the heat source of the carbonization chamber is provided by a certain proportion of coke oven gas and blast furnace gas heating the vertical fire channel, and the waste gas produced by heating the gas is called coke oven waste gas; and the gas contains a certain amount of H ₂ S and other sulfides generate SO ₂ after combustion, and nitrogen oxides NOx are generated when gas and air are burned in the vertical flue of the coke oven (there are three kinds of temperature thermal type, hydrocarbon fuel fast type and nitrogen-containing component fuel type). At present, no measures have been taken to reduce the emission of sulfur dioxide and nitrogen oxides in coke oven exhaust gas in China. According to the detection of the environmental protection department, most of the concentrations of SO ₂ and NOx emitted by domestic coke ovens cannot meet the latest "Coking Chemical Industry Pollutants" issued by the country. Emission Standards". And the new "Standard" has higher requirements on the emission concentration of SO ₂ and NOx starting from January 1, 2015. Therefore, the transformation of desulfurization and denitrification of coke oven is an urgent task to control air pollution, and the research on desulfurization and denitrification technology of coke oven exhaust gas has extremely far-reaching significance.

Invention content:

In order to overcome the defects of the existing technology, the purpose of this utility model is to provide an integrated device for desulfurization and denitrification of coke oven flue gas, focusing on solving the technology of sulfur dioxide and nitrogen oxide emission standards suitable for the characteristics of my country's coke oven process and flue gas characteristics , to develop an integrated device for coke oven flue gas desulfurization and denitrification. The device can effectively improve the desulfurization and denitrification efficiency of flue gas and the utilization rate of desulfurization and denitrification absorbent, and the cost of the device is lower than that of SCR/SNCR denitrification devices commonly used in thermal power plants, and the alkaline absorption liquid can be made of cheap calcium alkali Regeneration, desulfurization by-product gypsum and denitrification by-product nitrate can be recovered.

The utility model solves the technical problem and adopts the following technical solutions:

An integrated device for desulfurization and denitrification of coke oven flue exhaust gas, a flue gas inlet is provided on the side of the reaction tower, and a desulfurization area, a denitrification area, and a demisting area are sequentially arranged in the reaction tower above the flue gas inlet, The top of the reaction tower is provided with a flue gas outlet; the inside of the reaction tower is set as a slurry pool below the flue gas inlet.

The desulfurization area is provided with several desulfurization spray heads, and several desulfurization spray heads are connected in parallel on the first circulation pipeline; Connected to the second circulation pipeline; the first circulation pipeline and the second circulation pipeline communicate with the slurry pool and/or the solution pool.

Several ozone shower heads are arranged below the denitrification shower head, and each ozone shower head communicates with the ozone preparation device through an ozone delivery pipeline.

The demisting area is provided with several water mist nozzles, and the several water mist nozzles are alternately arranged on the spray water pipeline, and the spray water pipeline is connected with the flushing water tank, and a flushing pump is provided on the pipeline.

The slurry pool communicates with the absorption liquid preparation device through a delivery pipeline, and a feed pump is arranged on the delivery pipeline.

The solution pool is connected to the transition pool, the transition pool is connected to the regeneration pool, and the regeneration pool is respectively connected to the alkaline solution preparation system and the slurry pool, and the regeneration pool and the by-product recovery treatment system form a closed loop through pipelines, A slurry pump is provided on the pipeline to pump the slurry in the regeneration tank to the by-product recovery treatment system.

An induced draft fan is provided at the flue gas outlet.

Compared with the prior art, the beneficial effects of the utility model are reflected in:

The utility model has the advantages of low investment, low energy consumption, simple and reliable system, low operating cost, high utilization rate of on-site resources, high desulfurization and denitrification efficiency, desulfurization efficiency of more than 95%, and denitrification efficiency of more than 80%. It fully complies with the national coking chemical industry pollutant discharge standard.

The utility model is based _on the principle of oxidation absorption, and is a new method for removing NOx and SO2 from flue gas. The NO ₂ content of the NOx reaches 50% of the total NOx, so that it can be combined with NO to form N ₂ O ₃ , which is easily soluble in alkali solution, and then the sulfur dioxide and nitrogen oxides can be absorbed by the alkaline absorption solution. The resulting reaction liquid reacts with Ca(OH) ₂ to regenerate the alkaline absorption liquid for recycling, and the oxidized by-products nitrate and gypsum are recovered separately. The desulfurization efficiency of the device is above 95%, and the denitrification efficiency is above 80%.

Description of drawings:

Fig. 1 is the structural representation of the utility model.

Labels in the figure: 1 reaction tower, 2 by-product recovery and treatment system, 3 ozone preparation device, 4 flue gas inlet, 5 defogging area, 6 denitrification area, 7 desulfurization area, 8 slurry tank, 9 circulation pump, 10 first cycle Pipeline, 11 desulfurization spray head, 12 denitrification spray head, 13 liquid feed pump, 14 absorption liquid preparation device, 15 regeneration tank, 16 flue gas outlet, 17 induced draft fan, 18 transition tank, 19 solution tank, 20 slurry pump , 21 alkaline solution preparation system, 22 flushing water tank, 23 flushing pump, 24 second circulation pipeline.

The utility model will be further described below through specific embodiments in conjunction with the accompanying drawings.

Detailed ways:

Embodiment: The device of this embodiment is provided with a flue gas inlet 4 on the side of the reaction tower 1, and the reaction tower 1 is provided with a desulfurization zone 7, a denitrification zone 6, and a demisting zone 5 successively above the flue gas inlet 4. The reaction tower A flue gas outlet 16 is provided at the top of the reactor; a slurry pool 8 is located below the flue gas inlet 4 in the reaction tower.

The desulfurization zone 7 is provided with several desulfurization spray heads 11, and several desulfurization spray heads are connected in parallel on the first circulation pipeline 10; On the second circulation pipeline 24 ; the first circulation pipeline and the second circulation pipeline communicate with the slurry pool and/or the solution pool 19 .

Several ozone shower heads are arranged below the denitrification shower head 12, and each ozone shower head communicates with the ozone preparation device 3 through an ozone delivery pipeline. The demister area 5 is also provided with several water mist nozzles, which are alternately arranged at intervals on the spray water pipeline, and the spray water pipeline is connected with the flush water tank 22, and a flush pump 23 is provided on the pipeline.

The slurry pool 8 communicates with the absorption liquid preparation device 14 through the delivery pipeline, and a feed pump 13 is arranged on the delivery pipeline.

The solution pool 19 is connected to the transition pool 18, and the transition pool is connected to the regeneration pool 15, and the regeneration pool 15 is connected to the alkaline solution preparation system 21 and the slurry pool 8 respectively, and the regeneration pool 15 and the by-product recovery treatment system 2 form a closed loop through pipelines, And a slurry pump 20 is provided on the pipeline to pump the slurry in the regeneration tank 15 to the by-product recovery treatment system 2 .

The working principle and working process are as follows:

The coke oven flue gas enters the desulfurization and denitrification reaction tower 1 from the flue gas inlet 4, and the flue gas enters the denitrification area 6 after being washed by the alkaline absorption liquid sprayed by the desulfurization spray head 11 in the desulfurization area 7, and at the same time, the air enters the ozone preparation device 3 , the prepared _O3 enters the denitrification zone ₆ through the pipeline and mixes with the flue gas, so that the NO2 in the flue gas accounts for about 50% of the total volume of _NOx , and then reacts with the alkaline absorption liquid sprayed by the denitrification spray head 12 Remove _NOx . The reacted clean gas passes through the demisting zone 5 and goes to the flue gas outlet 16, then enters the chimney through the induced draft fan 17 and is discharged to the atmosphere.

Among them, the alkaline absorption liquid required by the desulfurization zone 6 and the denitrification zone 7 is supplied by the circulation pump 9, and the first circulation pipeline 10 and the second circulation pipeline 24 are respectively equipped with circulation pumps, and the two circulation pipelines are connected to the slurry of the reaction tower 1. The pool 8 and the solution pool 19 for storing the regenerated alkaline absorption liquid; the demisting area 5 mainly includes a flushing pump 23, a flushing water tank 22, and the like.

The circulating alkaline absorption liquid in the slurry tank 8 is properly replenished in a small amount by the absorption liquid preparation device 14 through the feed liquid pump 13 . The slurry at the bottom of the slurry tank 8 reaches the set pH value and is discharged into the regeneration tank 15, and the alkaline absorption solution regenerated by reacting with the calcium hydroxide solution added by the calcium hydroxide solution preparation system 21 is pumped into the absorption system by the circulation pump 9 for recycling. The slurry after the regeneration reaction is pumped into the by-product recovery treatment system 2 through the slurry pump 20 to be oxidized and recovered to obtain calcium sulfate and nitrate.

The by-products gypsum and nitrate can be sold as products. The system structure is simple and occupies a small area, and has high reliability. The system availability rate can reach more than 98%; there is no secondary pollution.

The device adopts ozone and lye denitrification and double alkali desulfurization process; the absorption liquid regeneration system uses but not limited to cheap Ca(OH) ₂ as the regeneration reagent; the absorption system uses but not limited to NaOH as the absorption liquid for desulfurization and denitrification.

_The NO2 gas adopts the _O3 oxidation production process, and the NO2 produced by the reaction accounts for 50% of the total volume of NOx _; after the coke oven flue gas enters the reaction tower, it first reacts with the alkaline absorption liquid in the desulfurization zone to form sulfite, Sulfate, a small amount of nitrite, and nitrate are mixed with O ₃ through the denitrification zone to make part of NO react to produce NO ₂ . The mixed gas is absorbed by the alkaline absorption liquid in the denitrification zone to generate nitrite and part of nitrate. The alkaline absorption liquid absorbs sulfur dioxide and nitrogen oxides and then flows into the slurry pool. When the pH value of the slurry pool reaches the set value, the mixed solution is discharged into the regeneration pool and regenerated with Ca(OH) _2. The regenerated alkaline absorption liquid is circulated The pump is pumped into the absorption system for recycling, and the slurry after the regeneration reaction is pumped into the by-product recovery and treatment system through the slurry pump. The treated clean flue gas is demisted by the demisting area and then discharged from the chimney to the atmosphere through the induced draft fan. The device can be equipped with a multi-layer spray reaction area.

Adopt above-mentioned method, the removal process of sulfur dioxide, nitrogen oxides in coke oven flue gas is as follows: (here only with sodium hydroxide as the example when alkaline absorption liquid)

NO+O ₃ →NO ₂ +O ₂

2NaOH+SO ₂ →Na ₂ SO ₃ +H ₂ O

2Na ₂ SO ₃ +O ₂ →2Na ₂ SO ₄

2NaOH+NO+NO ₂ →2NaNO ₂ +H ₂ O

2NaNO ₂ +O ₂ →2NaNO ₃

Ca(OH) ₂ +Na ₂ SO ₃ →CaSO ₃ ↓+2NaOH

Ca(OH) ₂ +Na ₂ SO ₄ →CaSO ₄ ↓+2NaOH

2CaSO ₃ +O ₂ →2CaSO ₄

Claims (7)

1. a coke oven flue exhuast gas desulfurization denitrification integrated device, smoke inlet (4) is provided with at the sidepiece of reaction tower (1), it is characterized in that: the inherent described smoke inlet (4) of described reaction tower (1) top is provided with desulfurization zone (7), denitration region (6) successively, except fog-zone (5), the top of reaction tower is provided with exhanst gas outlet (16); The below being positioned at smoke inlet (4) in reaction tower is set to slurry pool (8).

2. a kind of coke oven flue exhuast gas desulfurization denitrification integrated device according to claim 1, it is characterized in that, described desulfurization zone (7) are provided with several desulfurization spray head (11), several described desulfurization spray head is connected on the first circulating line (10) side by side; Described denitration region (6) is provided with several denitration spray head (12), several described denitration spray head is connected on the second circulating line (24) side by side; Described first circulating line, the second circulating line are communicated with described slurry pool and/or solution pool (19).

3. a kind of coke oven flue exhuast gas desulfurization denitrification integrated device according to claim 2, it is characterized in that, be provided with several ozone shower nozzle in the below of described denitration spray head (12), each described ozone shower nozzle is communicated with Ozone generation device (3) through ozone transport conduit.

4. a kind of coke oven flue exhuast gas desulfurization denitrification integrated device according to claim 1, it is characterized in that, described fog-zone (5) of removing is provided with several waterfog head, several described waterfog head is interleaved arrangement on shower water pipeline, described shower water pipeline is communicated with flush box (22), and on pipeline, be provided with flushing pump (23).

5. a kind of coke oven flue exhuast gas desulfurization denitrification integrated device according to claim 1 and 2, it is characterized in that, described slurry pool (8) is communicated with absorbing liquid preparation facilities (14) through conveyance conduit, and on described conveyance conduit, be provided with liquid-feeding pump (13).

6. a kind of coke oven flue exhuast gas desulfurization denitrification integrated device according to claim 2, it is characterized in that, described solution pool (19) is communicated with transition pond (18), described transition pond is communicated with regenerated reactor (15), described regenerated reactor (15) is communicated with alkaline solution preparation system (21) and slurry pool (8) respectively, and, described regenerated reactor (15) and by-product recovery treatment system (2) form a closed cycle by pipeline, and on pipeline, be provided with Pulp pump (20) slush pump in regenerated reactor (15) is delivered to described by-product recovery treatment system (2).

7. a kind of coke oven flue exhuast gas desulfurization denitrification integrated device according to claim 1, is characterized in that, be provided with air-introduced machine (17) at described exhanst gas outlet.