The full negative pressure coke oven gas purifying combination process
Technical field
The invention belongs to the coal tar field, particularly a kind of full negative pressure coke oven gas purifying combination process.
Background technology
The purification of coke-oven gas realizes by following steps in the coking industry: coal gas cooling, coal gas take off naphthalene, coal gas takes off benzene except that tar, coal gas desulfurization, coal gas deamination, coal gas and the coal gas supercharging is carried.
The operation or the application art of each step correspondence are as follows:
Coal gas cooling: primary-cooling working procedure, middle cooling working procedure, final cooling process.In the coal gas process of cooling, coal gas by be able to refrigerative after heat-eliminating medium directly contacts, be direct process for cooling; Coal gas is able to refrigerative after by heat exchange tube wall and heat-eliminating medium indirect heat exchange, is indirect process for cooling.
Coal gas takes off naphthalene: the tar washing oil that the tar-ammoniacal liquor of primary-cooling working procedure is washed naphthalene, middle cooling working procedure is washed the solar oil that the washing naphthalene of naphthalene, final cooling process or tar washing oil wash naphthalene and independently take off the naphthalene operation and is washed naphthalene.
Coal gas removes tar: the electric fishing operation, and by the tar fog in the electrical tar precipitator capture coal gas.
Coal gas desulfurization: desulfurization process has the kinds of processes practical application, and technology is divided three classes, i.e. wet oxidation process sulfur removal technology, wet absorption---desorption method sulfur removal technology and dry desulfurizing process; Wherein, the absorption agent difference of wet absorption---desorption method sulfur removal technology because of using, (absorption agent is Na to be divided into ammonia process (absorption agent is an ammoniacal liquor, i.e. the ammoniacal liquor sulfur removal technology) and alkaline process again
2CO
3Or K
2CO
3, i.e. vacuum carbonate technology).
The coal gas deamination: the deamination operation has the kinds of processes practical application, and technology is divided three classes, and promptly washes ammonia process, sulfuric acid absorption technology and phosphoric acid absorption technique.
Coal gas takes off benzene: wash the benzene operation, by the benzene hydrocarbon (benzene,toluene,xylene etc.) in the tar washing oil absorption coal gas.
The coal gas supercharging is carried: the air blast operation, by gas blower the coal gas supercharging is carried.So the operating pressure of coal gas system is a negative pressure before gas blower; The operating pressure of coal gas system is a malleation behind gas blower.
In the prior art, the combination process of coke oven gas purification is divided into by operating pressure: part negative pressure flow process and full negative pressure flow process.
As shown in Figure 3, the process configurations of the part negative pressure flow process of described gas purification is: primary-cooling working procedure and electric fishing operation place before the air blast operation, are the negative pressure flow process; In cooling working procedure, final cooling process, desulfurization process, deamination operation and wash the benzene operation and place after the air blast operation, be the malleation flow process.The malleation flow process is from the chemical engineering unit operation principle, should help washing and absorb operation, but also there are a lot of drawbacks in the malleation flow process, the only whole cold increase energy consumption that is provided with just makes system operation cost rise more than 100 ten thousand yuan/year, and, cold process influence coal gas ratio of ammonia-sulfur reduces desulfuration efficiency eventually, and whole cold type sewage enters the cyclic ammonia water system and causes equipment and pipeline corrosion.
As shown in Figure 2, the process configurations of the full negative pressure flow process of described gas purification then is: (washing ammonia-ammoniacal liquor sulfur removal technology is called ammonia sulphur cycle washing process for primary-cooling working procedure (coal gas cools off and take off naphthalene) → electric fishing operation (coal gas removes tar) → desulfurization and deamination operation.Remove ammonia and H in the coal gas
2S, HCN etc.) → benzene operation (coal gas takes off benzene) → air blast operation (coal gas supercharging conveying) washed.This full negative pressure flow process does not have final cooling process.These equipment are all operated under negative pressure state, and this just can fundamentally solve a series of problems that heat up and bring because of gas temperature behind the gas blower in the malleation flow process.Gas final cold system and yellow prussiate of potash production equipment can be set.Both saved initial cost, simplified technical process, can reduce the resistance of coal gas system again, and reduced the water at low temperature consumption and reduce system's total energy consumption.Because gas blower in flow process backmost, after purified gas compresses and heats up, become the undersaturated heating gas of crossing in machine.Thisly cross that heating gas is sent the coke oven heating back to or when carrying at a distance, do not separate out because of there being or having only a small amount of phlegma, alleviated Corrosion of Pipeline, the coal gas overbottom pressure can help the remote conveying of coal gas greater than 10kPa behind the machine.But this process using ammoniacal liquor is as the absorption agent of coal gas desulfurization, and deficiency is through reaching H after the desulfurization process processing
2S≤500mg/m
3Index.
Summary of the invention
For solving the prior art existing problems, the invention provides a kind of full negative pressure coke oven gas purifying combination process, this technology can improve H
2The absorption impellent of S is through reaching H after the desulfurization process processing
2S≤500mg/m
3Index.
For achieving the above object, full negative pressure coke oven gas purifying combination process provided by the invention is characterized in that, primary-cooling working procedure, electric fishing operation, deamination operation, washes benzene operation, desulfurization process and the air blast process sequence connects.
Further improvement of the present invention is that the deamination operation is used the ammonia in distilled ammonia wastewater, half rich ammoniacal liquor and the remained ammonia absorption coal gas.
Further improvement of the present invention is, deamination operation, the gas purification equipment work pressure of washing benzene operation, desulfurization process is-15~-1KPa.
Further improvement of the present invention is, the gas purification equipment of described each operation is one or serial or parallel connection many.
The present invention with fine purification technique for coke oven gas in the following order combining and configuring be the novel full negative pressure flow process of coke oven gas purification, primary-cooling working procedure (coal gas cooling and take off naphthalene) → electric fishing operation (coal gas removes tar) → deamination operation (washing ammonia process) → wash benzene operation (coal gas takes off benzene) → desulfurization process (wet absorption---the alkaline process in the desorption method sulfur removal technology, i.e. vacuum carbonate technology) → air blast operation (coal gas supercharging conveying).
About 80 ℃ thick coke-oven gas is cooled to 18~25 ℃ through primary-cooling working procedure; Remove wherein tar through the electric fishing operation again; Pass through the deamination operation then through distilled ammonia wastewater and remained ammonia absorption ammonia wherein, temperature is elevated to 20~27 ℃; By washing the benzene operation by the benzene hydrocarbon in the tar washing oil absorption coal gas, temperature is elevated to 22~30 ℃ again; Again through desulfurization process by Na
2CO
3Or K
2CO
3Absorption agent absorbs the H in the coal gas
2S, HCN; After the air blast operation is delivered to the user by gas blower with the purified gas supercharging.
With the gas purification equipment in coke oven gas purification deamination and the sulfur removal technology promptly: suction (washing) the ammonia tower in the washing ammonia process; Wash the thionizer of washing benzene tower and vacuum carbonate technology of benzene operation, the applied in any combination under the negative pressure working conditions.
Described deamination operation, wash the gas purification equipment in the kinds of processes of benzene operation, desulfurization process, its operating pressure is-15~-1KPa.
For guaranteeing the required service temperature of each operation gas purification equipment, described primary-cooling working procedure temperature of exit gas be coke-oven gas through the cooled temperature of primary-cooling working procedure between 18~25 ℃.
Owing to absorb heat release and avoid that the steam condensation enters in the tar washing oil in the coal gas, go out to wash benzene tower gas temperature and be higher than into 2~5 ℃ of tower gas temperatures.
The gas purification equipment of described each operation can be one or serial or parallel connection many.
The present invention compared with prior art has the following advantages:
(1) the present invention is except that ammonia sulphur cycle washing process, with a kind of coke oven gas purification deamination and sulfur removal technology also applied in any combination under condition of negative pressure.Before each cleaning section of coke-oven gas is located at the air blast operation, need be provided with yet and shifts out the coal gas temperature rise that gas blower produces by final cooling process; Reduce the consumption of the required low-temperature cooling water (7~18 ℃) of gas final cold operation cooling, also reduced the weight of coal gas cooling apparatus; Because when coal gas passed through each gas purification equipment successively before the air blast operation, temperature raise successively, pressure reduces successively, and the obstruction of naphthalene can not take place the gas purification equipment before the air blast operation.Whole gas purification unit is stable, reduces operator's labour intensity;
(2) the present invention compares with the ammonia sulphur cycle washing process of full negative pressure flow process, owing to adopt K
2CO
3Solution adopts the absorption agent of ammoniacal liquor as coal gas desulfurization as the absorption agent of coal gas desulfurization in the ammonia sulphur cycle washing process of comparing, improved H in the coal gas
2The absorption impellent of S, the H of coal gas after purifying
2S content is lower than 300mg/m
3, be better than the H of ammonia sulphur cycle washing process
2S content is lower than 500mg/m
3Index, the follow-up coal gas user of corresponding minimizing burning and exhausting SO
2Simultaneously, owing to absorb the raising of impellent, the energy consumption of coal gas desulfurization operation also descends to some extent.
Description of drawings
Fig. 1: full negative pressure coke oven gas purifying combination process schematic flow sheet
The 1-primary cooler; The 2-electrical tar precipitator; 3-inhales (washing) ammonia tower; 4-washes the benzene tower; The 5-thionizer; The 6-gas blower.
Fig. 2: prior art full negative pressure coke oven gas purifying combination process schematic flow sheet
The 1-primary cooler; The 2-electrical tar precipitator; The 3-thionizer; The 4-Ammonic washing tower; 5-washes the benzene tower; The 6-gas blower.
Fig. 3: prior art part negative pressure coke oven gas purifying combination process schematic flow sheet
The 1-primary cooler; The 2-electrical tar precipitator; The 3-gas blower; 4-final cooling tower (or whole cooler); 5-inhales (washing) ammonia tower; 6-washes the benzene tower; The 7-thionizer.
Embodiment:
Below in conjunction with accompanying drawing to the detailed description of the invention.
In Fig. 1, corresponding described coke oven gas purification deamination and sulfur removal technology, in the full negative pressure combination process of the present invention, the gas purification equipment of each operation and the coal gas out temperature of each operation see Table 1.
Table 1: the explanation and the device parameter of each numbering among Fig. 1
To cooperate 200 * 10
4The coke oven gas purification device of the oven battery in ton coke/year, normal coal gas treatment capacity are 10 * 10
4m
3/ h, thick coke-oven gas temperature are 80 ℃ and specify the present invention for example:
Thick coke-oven gas parameter: 80 ℃ of gas temperatures, 1 mark rice
3Contain 712.5g steam, 8~12g naphthalene, 20~40g tar, 4~9g ammonia, 4~8g hydrogen sulfide and 15~30g benzene hydrocarbon in the coal gas.Thick coke-oven gas at first enters primary cooler 1, and primary cooler 1 is the transverse tube type gas cooler, and the coke-oven gas heat-eliminating medium indirect heat exchange that heat transfer tube is outer and heat transfer tube is interior of from top to bottom flowing through is cooled off, and coke-oven gas is cooled to 18~25 ℃; In the coal gas process of cooling, the water vapor absorption of condensation the tar of part ammonia and dissolving part naphthalene together discharge from primary cooler 1 with the form of tar ammonia phlegma; The coal gas that goes out primary cooler 1 is saturated by steam, and 18~25 ℃, 1 mark rice
3Contain in the coal gas 16.76~26.0g steam, naphthalene<800mg ,~3g tar, 4~8g ammonia, 4~8g hydrogen sulfide and 15~30g benzene hydrocarbon.
Coke-oven gas enters the tar fog that electrical tar precipitator 2 captures in the coal gas then, makes the coal-tar middle oil mist content<50mg/m of the coal gas that draws electrical tar precipitator 2
3
The coal gas that goes out electrical tar precipitator 2 enters suction (washing) ammonia tower 3, inhaling (washing) ammonia tower 3 is absorption towers that inside is filled with filler or column plate, coal gas flows in inhaling (washing) ammonia tower 3 from bottom to top, add with segmentation, mobile absorption agent---distilled ammonia wastewater, half rich ammoniacal liquor and remained ammonia counter current contact from top to bottom, absorb the ammonia in the coal gas, the coal gas of using suction (washing) ammonia tower 3 contains ammonia<100mg/m
3The absorption heat part of ammonia is taken away by absorption liquid, and another part is taken away by coal gas, makes the gas temperature that draws suction (washing) ammonia tower 3 be elevated to 20~27 ℃.
Described remained ammonia derives from: tar ammonia phlegma and other production process superfluous water separate through tar ammonia, separate the tar that obtains and are coal-tar products; Separate the water obtain and be called ammoniacal liquor, except that the part that recycles, the unnecessary remained ammonia that is called.Remained ammonia adds by inhaling (washing) ammonia tower middle part; Described distilled ammonia wastewater derives from ammonia still process, being the absorption liquid that obtains behind the ammonia in the coal gas having absorbed---rich ammoniacal liquor (rich solution) is removed wherein ammonia through distillation, cat head goes out ammonia vapour, goes out distilled ammonia wastewater at the bottom of the tower, and a part of distilled ammonia wastewater is delivered to suction (washing) ammonia top of tower and added after cooling; The redundance distilled ammonia wastewater effluxes after sending sewage biochemical treatment operation to handle; Behind the distilled ammonia wastewater absorption ammonia of inhaling the adding of (washing) ammonia top of tower, become half rich ammoniacal liquor, after extracting cooling out in the tower, add by inhaling (washing) ammonia tower middle part again, inhale the rich ammoniacal liquor (rich solution) that obtains at the bottom of (washing) ammonia tower and deliver to ammonia still process again, constitute absorption---the circulation of desorb.
Coal gas enters subsequently washes benzene tower 4, absorbs benzene hydrocarbon in the coal gas by the tar washing oil in tower, owing to absorb heat release and avoid that the steam condensation enters in the tar washing oil in the coal gas, goes out the tower gas temperature and is higher than into 2~5 ℃ of tower gas temperatures; Go out to wash in the coal gas of benzene tower 5 and contain benzene hydrocarbon<10g/m
3
Coal gas enters thionizer 5 subsequently, passes through K in tower
2CO
3Or Na
2CO
3Absorption agent absorbs the H in the coal gas
2S, HCN, the coal gas of using thionizer 5 contains H
2S<300mg/m
3
The coke-oven gas of finishing after the purification is delivered to the user by gas blower with the purified gas supercharging at last.Because the coal gas temperature rise that the gas blower acting produces can reduce the generation of phlegma in the coal gas course of conveying.The gas purification equipment of described each operation can be one or serial or parallel connection many.
Comparative Examples 1
According to shown in Figure 3, adopt prior art coke oven gas purification part negative pressure flow operations, its flow process is a part negative pressure flow process, respectively numbers illustrated in table 2 among the figure.
Table 2: the explanation and the device parameter of each numbering among Comparative Examples 1 Fig. 2
Comparative Examples 2
According to shown in Figure 2, adopt the full negative pressure flow operations of prior art coke oven gas purification, its flow process is full negative pressure flow process, respectively numbers illustrated in table 3. among the figure
Table 3: the explanation and the device parameter of each numbering among Comparative Examples 2 Fig. 3
The embodiment of the invention 1 is compared with Comparative Examples 1, and technique effect is as follows:
(1) investment is simplified, is reduced in technical process:
The air blast operation is located at after all cleaning sections of coke-oven gas, the gas final cold operation need be set shift out the coal gas temperature rise that gas blower produces.
Cancelled the required subcooling water consumption of final cooling process, (public auxilliary operation) corresponding configurable steam double-effect type lithium-bromide absorption-type refrigerating machine group than ting model (needs refrigerating duty 150 * 10 less
4Kcal/h); Refrigeration cycle water pump and subcooling water pump then can be selected less model for use.
(2) operating performance:
When coal gas passed through each gas purification equipment successively behind primary-cooling working procedure, temperature raise successively, and pressure reduces successively, and the obstruction of naphthalene can not take place the gas purification equipment behind primary-cooling working procedure; Significantly reduce operator's labour intensity.
The air blast operation is located at after all cleaning sections of coke-oven gas, and gas blower produces the generation that the coal gas temperature rise can reduce phlegma in the coal gas course of conveying, slows down the corrosion of gas line.
(3) process energy consumption reduces:
A) the coal gas temperature rise that produces in gas blower acting is 10 ℃, reduces to shift out the required water at low temperature of coal gas temperature rise and consume 220m
3/ h;
The required about 30KW of power consumption of final cooling process low-temperature cooling water is carried in corresponding saving; And summer produce the required steam consumption 2.51t/h (0.6MPa) of final cooling process low-temperature cooling water, new water consumption 7.62m by refrigerator
3/ h, the about 95KW of power consumption; Then produce low-temperature cooling water by cooling tower winter, required new water consumption 2.6m
3/ h;
Annual conservation of power consumes 6.41 * 10
5KWh; New water consumption 5.21 * 10
4m
3Steam consumption 1.47 * 10
4T; Amount to 2240 tons of standard coals.
The embodiment of the invention 1 is compared with Comparative Examples 2, and technique effect is as follows:
(1) absorbs the H that impellent improves, purifies back coal gas
2S content is low:
The present invention adopts vacuum K
2CO
3Coal gas desulfurization technology, the H of coal gas after purifying
2S content is lower than 300mg/m
3And Comparative Examples 2 adopts the coal gas desulfurization deamination technology of ammonia sulphur cycle washing, purifies the H of back coal gas
2S content is lower than 500mg/m
3
(2) absorb impellent raising, process energy consumption reduction:
Compare ammonia sulphur cycle washing process; Increase electric power and consume 620KW; Save steam consumption 7t/h (0.6MPa); Save subcooling water consumption 730m
3/ h; Economized cycle cooling-water consumption 500m
3/ h;
The about 99KW of power consumption that corresponding saving transporting low temperature water coolant is required; And summer produce the required steam consumption 8.3t/h (0.6MPa) of low-temperature cooling water, new water consumption 25.3m by refrigerator
3/ h, the about 215KW of power consumption; Then produce low-temperature cooling water by cooling tower winter, required new water consumption 8.6m
3/ h;
The about 68KW of power consumption that corresponding saving delivery cycle water coolant is required; Required new water consumption 8m
3/ h;
Adding up to increases electric power every year consumes 2.71 * 10
6KWh; Reduce new water consumption 2.43 * 10
5m
3Reduce steam consumption 1.10 * 10
5T; Amount to 13770 tons of standard coals.
(3) reduce public auxilliary operation plant investment:
The subcooling water consumption of saving then needs refrigerating duty 511 * 10 less
4Kcal/h, public auxilliary operation is corresponding can dispose (a refrigerating duty 450 * 10 less
4Kcal/h) steam double-effect type lithium-bromide absorption-type refrigerating machine group; Refrigeration cycle water pump, subcooling water pump and recirculated cooling water pump then can be selected less model for use.