Summary of the invention
Therefore, the object of the present invention is to provide method and the device of a kind of generation synthetic natural gas (Synthetic Natural Gas, SNG).
The present invention realizes by the following technical solutions.
The invention provides a kind of method of producing synthetic natural gas.See figures.1.and.2, described method comprises the following steps:
A) unstripped gas (1) 1:(0.5 ~ 5 by volume after the first heat-exchange equipment (2) is warming up to 150 ~ 350 ℃): (0 ~ 0.5): (0 ~ 0.5) is divided into first strand of unstripped gas (4), second strand of unstripped gas (5), the 3rd strand of unstripped gas (6) and the 4th strand of unstripped gas (7);
B) circulation gas (19) after the first strand of unstripped gas (4) in step a) and the first steam (37) and supercharging being mixed to get to temperature is first gas mixture (8) of 250 ~ 400 ℃, the first gas mixture (8) is passed in first paragraph methanator (9) and reacted, obtain temperature and be the first paragraph gas product (10) of 450 ~ 750 ℃, this first paragraph gas product (10) is cooled to 250 ~ 400 ℃ of first paragraph gas products (12) after being lowered the temperature through the second heat-exchange equipment (11,11 ');
C) the first paragraph gas product (12) after cooling step b) being obtained is (0.3 ~ 5) by volume: 1 is divided into circulation gas (13) and second strand of first paragraph gas product (14), described circulation gas (13) is lowered the temperature through the 3rd heat-exchange equipment (15), obtain temperature and be the circulation gas 16 of 100 ~ 350 ℃, circulation gas 16 obtains the circulation gas (18) after supercharging through recycle compressor (17) supercharging, circulation gas after supercharging (18) heats up through the 3rd heat-exchange equipment (15), obtains temperature and be the circulation gas (19) after the described supercharging of 250 ~ 350 ℃;
D) the second strand of first paragraph gas product (14) after cooling step c) being obtained and described second strand of unstripped gas (5), it is second gas mixture (20) of 250 ~ 400 ℃ that the second steam (38) is mixed to get temperature, the second gas mixture (20) is passed in second segment methanator (21) and reacted, obtain temperature and be the second segment gas product (22) of 450 ~ 700 ℃, this second segment gas product (22) is through the 4th heat-exchange equipment (23, 23 ') cooling, obtain the second segment gas product (24 after the cooling of 350 ~ 550 ℃ of temperature, 24 '), second segment gas product (24 after cooling, 24 ') through the 5th heat-exchange equipment (25, 25 ') be cooled to 200 ~ 400 ℃ of second segment gas products (26) after being lowered the temperature,
E) it is the 3rd gas mixture (27) of 200 ~ 400 ℃ that the second segment gas product (26) after cooling step d) being obtained and described the 3rd strand of unstripped gas (6), the 3rd steam (39) are mixed to get temperature, the 3rd gas mixture (27) is passed in the 3rd section of methanator (28) and reacted, obtain temperature and be the 3rd section of gas product (29) of 300 ~ 550 ℃, the three section gas product (30) of the 3rd section of gas product (29) after described the first heat-exchange equipment (2) is cooled to 60 ~ 350 ℃ of coolings that obtain;
F) it is the 4th gas mixture (31) of 60 ~ 200 ℃ that the 3rd section of gas product (30) after cooling step e) being obtained and described the 4th strand of unstripped gas (7), the 4th steam (40) are mixed to get temperature, described the 4th gas mixture (31) heats up and to obtain the 4th gas mixture 33 after temperature is the intensification of 200 ~ 350 ℃ through the 6th heat-exchange equipment (32), the 4th gas mixture 33 after intensification passes in the 4th section of methanator (34) and reacts, and obtains temperature and be the 4th section of gas product (35) of 250 ~ 450 ℃;
G) it is the gas product (36) of 20 ~ 80 ℃ that the 4th section of gas product (35) step f) being obtained obtains temperature after the 6th heat-exchange equipment (32) is lowered the temperature and carried out gas-liquid separation.
Preferably, the molar percentage of described unstripped gas (1) is composed as follows: carbon monoxide 5 ~ 50%, carbonic acid gas 0 ~ 30%, hydrogen 20 ~ 80%, methane 0 ~ 20%.
Preferably, in described step a), the volume ratio of first strand of unstripped gas (4) that described unstripped gas (1) is divided into, second strand of unstripped gas (5), the 3rd strand of unstripped gas (6) and the 4th strand of unstripped gas (7) can be 1:(0.5 ~ 2): (0 ~ 0.3): (0 ~ 0.3).
Preferably, in described step c), the circulation gas (13) that the first paragraph gas product (12) after described cooling is divided into and the volume ratio of second strand of first paragraph gas product (14) can be (0.3 ~ 3): 1.
In a kind of preferred embodiment of the present invention, described method also comprises utilizes methanation reaction heat release in the following manner: make the oiler feed (41 from battery limit (BL), 41 ') enter drum (42, 42 '), make from drum (42, 42 ') the first oiler feed (43, 43 ') enter described the second heat-exchange equipment (11, 11 ') produce the first saturation steam (44 of 3 ~ 10MPa, 44 '), make from drum (42, 42 ') the second oiler feed (45, 45 ') enter described the 4th heat-exchange equipment (23, 23 ') or described the 5th heat-exchange equipment (25, 25 ') produce the second saturation steam (46 of 3 ~ 10MPa, 46 '), from drum (42, 42 ') the 3rd saturation steam (47, 47 ') through described the 5th heat-exchange equipment (25, 25 ') or described the 4th heat-exchange equipment (23, 23 ') heat up, obtain temperature and be the superheated vapour (48 of 300 ~ 550 ℃, 48 ').
In the above-mentioned mode of utilizing methanation reaction heat release, when the second oiler feed (45,45 ') enters the 4th heat-exchange equipment (23,23 '), the 3rd saturation steam (47,47 ') heats up through the 5th heat-exchange equipment (25,25 '); When the second oiler feed (45,45 ') enters the 5th heat-exchange equipment (25,25 '), the 3rd saturation steam (47,49 ') heats up through the 4th heat-exchange equipment (23,23 ').
According to the method for production synthetic natural gas provided by the invention, it is raw material that the method be take coal or gasifying biomass product, production synthetic natural gas, and the molar percentage that contains methane in the synthetic natural gas product of gained is more than 94%.
On the other hand, the present invention also provides the device for aforesaid method provided by the invention, and this device comprises:
Methanator, comprises first paragraph methanator (9), second segment methanator (21), the 3rd section of methanator (28) and the 4th section of methanator (34) for carrying out methanation reaction;
Heat-exchange equipment, comprise for heating and/or the first heat-exchange equipment (2), second heat-exchange equipment (11 of cooling gas, 11 '), the 3rd heat-exchange equipment (15), the 4th heat-exchange equipment (23,23 '), the 5th heat-exchange equipment (25,25 ') and the 6th heat-exchange equipment (32);
Recycle compressor, comprises for by the recycle compressor of circulation gas supercharging (17).
In the preferred embodiment of present device, described first paragraph methanator (9), second segment methanator (21), the 3rd section of methanator (28) and the 4th section of methanator (34) are insulation fix bed methanator.
Preferably, described device also comprises drum (42,42 '), is used to heat-exchange equipment that oiler feed is provided and accepts the saturation steam that heat-exchange equipment produces, and saturation steam is delivered to heat-exchange equipment simultaneously.Particularly, described drum (42, 42 ') be used to the second heat-exchange equipment (11, 11 ') the first oiler feed (43 is provided, 43 '), and accept the second heat-exchange equipment (11, 11 ') the first saturation steam (44 of producing, 44 '), it is the 4th heat-exchange equipment (23, 23 ') or the 5th heat-exchange equipment (25, 25 ') the second oiler feed (45 is provided, 45 '), and accept the 4th heat-exchange equipment (23, 23 ') or the 5th heat-exchange equipment (25, 25 ') the second saturation steam (46 of producing, 46 '), simultaneously by the 3rd saturation steam (47, 47 ') be delivered to the 4th heat-exchange equipment (23, 23 ') or the 5th heat-exchange equipment (25, 25 ').
Preferably, described heat-exchange equipment is selected from useless pot and vapor superheater.
Preferably, described device also comprises desulphurization reactor, for unstripped gas is carried out to deep desulfuration.
Preferably, described device also comprises deoxidation reactor, for unstripped gas is carried out to degree of depth deoxidation.
Preferably, described device also comprises gas-liquid separator, for separating of the water of condensation in process gas.
The invention provides a kind of continuous processing flow process and device of take coal or the synthetic natural gas of gasifying biomass product more than raw material production contains methane 94mol%.Technical process provided by the invention is as follows: unstripped gas is divided into four strands after preheating, and wherein first strand of unstripped gas enters first paragraph methanator after mixing with steam, circulation gas and react; First strand of gas product is divided into two strands, after the first stock-traders' know-how recycle compressor supercharging, enter first paragraph methanator, after second strand of first paragraph gas product and second strand of unstripped gas and vapor mixing, enter second segment methanator and react, after second segment gas product and the 3rd strand of unstripped gas, vapor mixing, enter the 3rd section of methanator and react; After the 3rd section of gas product and the 4th strand of unstripped gas, vapor mixing, enter the 4th section of methanator and react, the 4th section of gas product obtains gas product after gas-liquid separation.
In technique of the present invention, contain independent steam system, steam is mixed into corresponding methanator with unstripped gas respectively, can control preferably reactor outlet temperature; the flow of this steam can modulation, mixes on the one hand CO content in reduction unstripped gas with unstripped gas; control temperature of reaction; on the other hand can Optimization Technology, reduce circulating flow rate, reduce system energy consumption; improve energy utilization efficiency; also can, under the condition of unstripped gas fluctuation, control temperature of reaction, guard catalyst.Steam at least a portion derives from the steam of heat-exchange equipment by-product.
In technique of the present invention, contain the production of steam system of utilizing methanation reaction heat, can produce according to actual needs saturation steam and the superheated vapour of different grades.Oiler feed enters drum, and drum is that heat-exchange equipment is carried oiler feed and collected by riser the saturation steam that heat-exchange equipment produces by downtake, and saturation steam is delivered to heat-exchange equipment intensification obtains superheated vapour.
If still contain a small amount of carbon monoxide and carbonic acid gas in gas product of the present invention, gas further can be reacted and obtains the finished product.
Compared with prior art, the present invention has realized the synthetic gas full methanation after purifying by coal or gasifying biomass product and has carried out production synthetic natural gas, has technical process reasonable, possesses operability; Capacity usage ratio is high, save energy, advantages of environment protection.
Embodiment
Below in conjunction with embodiment, the present invention is further described in detail, the embodiment providing is only in order to illustrate the present invention, rather than in order to limit the scope of the invention.
embodiment 1
The present embodiment is a kind of preferred implementation of the production method of synthetic natural gas provided by the invention, and the process flow sheet of the present embodiment as shown in Figure 1.
A) coal or biomass are met the unstripped gas of requirement through gasification unit, converter unit and clean unit.Unstripped gas 1 is warming up to the unstripped gas 3 after being heated up after 210 ~ 230 ℃ through the first heat-exchange equipment 2.Unstripped gas 3 after intensification is divided into four bursts of logistics, that is: first strand of unstripped gas 4, second strand of unstripped gas 5, the 3rd strand of unstripped gas 6 and the 4th strand of unstripped gas 7.
B) first strand of unstripped gas 4 mixed with the circulation gas 19 after the first steam 37 and supercharging, obtain temperature and be first gas mixture 8 of 280 ~ 300 ℃, passed in first paragraph methanator 9 and carried out methanation reaction, obtained temperature and be the first paragraph gas product 10 of 660 ~ 680 ℃.First paragraph gas product 10 is cooled to 320 ~ 340 ℃ of first paragraph gas products 12 after being lowered the temperature, simultaneously by-product saturation steam through the second heat-exchange equipment 11.
C) the first paragraph gas product 12 after cooling is divided into circulation gas 13 and second strand of first paragraph gas product 14, circulation gas 13 is through the 3rd heat-exchange equipment 15 coolings, obtain temperature and be the circulation gas 16 of 170 ~ 190 ℃, circulation gas 16 obtains the circulation gas 18 after supercharging through recycle compressor 17 superchargings, loop compression acc power is 896kW, circulation gas 18 after supercharging heats up through the 3rd heat-exchange equipment 15, obtains temperature and be the circulation gas 19 after the supercharging of 290 ~ 310 ℃;
D) second segment first paragraph gas product 14 and second strand of unstripped gas 5, second steam 38 being mixed to get to temperature is second gas mixture 20 of 290 ~ 310 ℃, the second gas mixture 20 is passed in second segment methanator 21 and reacted, obtain temperature and be the second segment gas product 22 of 620 ~ 640 ℃, this second segment gas product 22 is through the 4th heat-exchange equipment 23 coolings, obtain the second segment gas product 24 after the cooling of 480 ~ 500 ℃ of temperature, the second segment gas product 24 after cooling is cooled to 280 ~ 300 ℃ of second segment gas products 26 after being lowered the temperature through the 5th heat-exchange equipment 25;
E) the second segment gas product 26 after cooling and the 3rd strand of unstripped gas 6, the 3rd steam 39 being mixed to get to temperature is the 3rd gas mixture 27 of 280 ~ 300 ℃, the 3rd gas mixture 27 is passed in the 3rd section of methanator 28 and reacted, obtain temperature and be 29, the three sections of gas products 29 of the 3rd section of gas product of 480 ~ 500 ℃ the 3rd section of gas product 30 after the first heat-exchange equipment 2 is cooled to 80 ~ 100 ℃ of coolings that obtain;
F) the 3rd section of gas product 30 after cooling and the 4th strand of unstripped gas 7, the 4th steam 40 being mixed to get to temperature is the 4th gas mixture 31 of 70 ~ 90 ℃, described the 4th gas mixture 31 heats up and obtains the 4th gas mixture 33 after temperature is the intensification of 250 ~ 270 ℃ through the 6th heat-exchange equipment 32, the 4th gas mixture 33 after intensification passes in the 4th section of methanator 34 and reacts, and obtains temperature and be the 4th section of gas product 35 of 370 ~ 390 ℃;
G) the 4th section of gas product 35 being obtained after the 6th heat-exchange equipment 32 is lowered the temperature and carried out gas-liquid separation to temperature is the gas product 36 of 30 ~ 50 ℃.
Wherein, the technique of utilizing of methanation reaction heat release comprises: the oiler feed 41 from battery limit (BL) enters drum 42, the first oiler feed 43 from drum 42 enters the first saturation steam 44 that the second heat-exchange equipment 11 produces 3 ~ 10MPa, the second oiler feed 45 from drum 42 enters the second saturation steam 46 that the 4th heat-exchange equipment 23 produces 3 ~ 10MPa, from the 3rd saturation steam 47 of drum 42, through the 5th heat-exchange equipment 25, heat up, obtain temperature and be the superheated vapour 48 of 440 ~ 460 ℃.
Wherein, the volume ratio of first strand of unstripped gas 4, second strand of unstripped gas 5, the 3rd strand of unstripped gas 6 and the 4th strand of unstripped gas 7 is 1:0.33:0.04:0, and the volume ratio of circulation gas 13 and second strand of first paragraph gas product 14 is 1:0.54.
Below by the gas composition parameter of each logistics in table 1, a situation arises to have described intuitively the reality of each workshop section's methanation reaction in the technical process shown in Fig. 1.
Table 1
The explanation of logistics numbering: 1 is unstripped gas; 8 is the first gas mixture; 10 is first paragraph gas product; 20 is the second gas mixture; 22 is second segment gas product; 27 is the 3rd gas mixture; 29 is the 3rd section of gas product; 33 is the 4th gas mixture after heating up; 35 is the 4th section of gas product; 13 is circulation gas; 36 is gas product SNG; 48 is superheated vapour.
embodiment 2
The present embodiment is a kind of preferred implementation of the production method of synthetic natural gas provided by the invention, and the process flow sheet of the present embodiment as shown in Figure 2.
A) coal or biomass are met the unstripped gas of requirement through gasification unit, converter unit and clean unit.Unstripped gas 1 is warming up to the unstripped gas 3 after being heated up after 190 ~ 210 ℃ through the first heat-exchange equipment 2.Unstripped gas 3 after intensification is divided into four bursts of logistics, that is: first strand of unstripped gas 4, second strand of unstripped gas 5, the 3rd strand of unstripped gas 6 and the 4th strand of unstripped gas 7.
B) first strand of unstripped gas 4 mixed with the circulation gas 19 after the first steam 37 and supercharging, obtain temperature and be first gas mixture 8 of 280 ~ 300 ℃, passed in first paragraph methanator 9 and carried out methanation reaction, obtained temperature and be the first paragraph gas product 10 of 600 ~ 620 ℃.First paragraph gas product 10 is cooled to 310 ~ 330 ℃ of first paragraph gas products 12 after being lowered the temperature, simultaneously by-product saturation steam through the second heat-exchange equipment 11.
C) the first paragraph gas product 12 after cooling is divided into circulation gas 13 and second strand of first paragraph gas product 14, circulation gas 13 is through the 3rd heat-exchange equipment 15 coolings, obtain temperature and be the circulation gas 16 of 190 ~ 210 ℃, circulation gas 16 obtains the circulation gas 18 after supercharging through 17 superchargings, circulation gas 18 after supercharging heats up through the 3rd heat-exchange equipment 15, obtains temperature and be the circulation gas 19 after the supercharging of 270 ~ 290 ℃;
D) second strand of first paragraph gas product 14 and second strand of unstripped gas 5, second steam 38 being mixed to get to temperature is second gas mixture 20 of 280 ~ 300 ℃, the second gas mixture 20 is passed in second segment methanator 21 and reacted, obtain temperature and be the second segment gas product 22 of 600 ~ 620 ℃, this second segment gas product 22 is through the 4th heat-exchange equipment 23 ' cooling, obtain second segment gas product 24 after the cooling of 380 ~ 400 ℃ of temperature ', the second segment gas product 26 of the second segment gas product 24 after cooling ' after 280 ~ 300 ℃ of the 5th heat-exchange equipments 25 ' be cooled to are lowered the temperature;
E) the second segment gas product 26 after cooling and the 3rd strand of unstripped gas 6, the 3rd steam 39 being mixed to get to temperature is the 3rd gas mixture 27 of 280 ~ 300 ℃, the 3rd gas mixture 27 is passed in the 3rd section of methanator 28 and reacted, obtain temperature and be 29, the three sections of gas products 29 of the 3rd section of gas product of 420 ~ 440 ℃ the 3rd section of gas product 30 after the first heat-exchange equipment 2 is cooled to 80 ~ 100 ℃ of coolings that obtain;
F) the 3rd section of gas product 30 after cooling and the 4th strand of unstripped gas 7, the 4th steam 40 being mixed to get to temperature is the 4th gas mixture 31 of 70 ~ 90 ℃, described the 4th gas mixture 31 heats up and obtains the 4th gas mixture 33 after temperature is the intensification of 240 ~ 260 ℃ through the 6th heat-exchange equipment 32, the 4th gas mixture 33 after intensification passes in the 4th section of methanator 34 and reacts, and obtains temperature and be the 4th section of gas product 35 of 310 ~ 330 ℃;
G) the 4th section of gas product 35 being obtained after the 6th heat-exchange equipment 32 is lowered the temperature and carried out gas-liquid separation to temperature is the gas product 36 of 30 ~ 50 ℃.
Wherein, the technique of utilizing of methanation reaction heat release comprises: from the oiler feed 41 of battery limit (BL) ' enter drum 42 ', from drum 42 ' the first oiler feed 43 ' enter the second heat-exchange equipment 11 ' produce 3 ~ 10MPa the first saturation steam 44 ', from drum 42 ' the second oiler feed 45 ' enter the 5th heat-exchange equipment 25 ' produce 3 ~ 10MPa the second saturation steam 46 ', from drum 42 ' the 3rd saturation steam 47 ' through the 4th heat-exchange equipment 23 ' intensification, obtain temperature and be 490 ~ 510 ℃ superheated vapour 48 '.
Wherein, the volume ratio of first strand of unstripped gas 4, second strand of unstripped gas 5, the 3rd strand of unstripped gas 6 and the 4th strand of unstripped gas 7 is 1:0.18:0.01:0, and the volume ratio of circulation gas 13 and second strand of first paragraph gas product 14 is 1:0.18.
Below by the gas composition parameter of each logistics in table 2, a situation arises to have described intuitively the reality of each workshop section's methanation reaction in Fig. 2 technical process.
Table 2
The explanation of logistics numbering: 1 is unstripped gas; 8 is the first gas mixture; 10 is first paragraph gas product; 20 is the second gas mixture; 22 is second segment gas product; 27 is the 3rd gas mixture; 29 is the 3rd section of gas product; 33 is the 4th gas mixture after heating up; 35 is the 4th section of gas product; 13 is circulation gas; 36 is gas product SNG; 48 ' be superheated vapour.
embodiment 3
The present embodiment is a kind of preferred implementation of the production method of synthetic natural gas provided by the invention, and the process flow sheet of the present embodiment as shown in Figure 1.
A) coal or biomass are met the unstripped gas of requirement through gasification unit, converter unit and clean unit.Unstripped gas 1 is warming up to the unstripped gas 3 after being heated up after 210 ~ 230 ℃ through the first heat-exchange equipment 2.Unstripped gas 3 after intensification is divided into four bursts of logistics, that is: first strand of unstripped gas 4, second strand of unstripped gas 5, the 3rd strand of unstripped gas 6 and the 4th strand of unstripped gas 7.
B) first strand of unstripped gas 4 mixed with the circulation gas 19 after the first steam 37 and supercharging, obtain temperature and be first gas mixture 8 of 290 ~ 310 ℃, passed in first paragraph methanator 9 and carried out methanation reaction, obtained temperature and be the first paragraph gas product 10 of 670 ~ 690 ℃.First paragraph gas product 10 is cooled to 320 ~ 340 ℃ of first paragraph gas products 12 after being lowered the temperature, simultaneously by-product saturation steam through the second heat-exchange equipment 11.
C) the first paragraph gas product 12 after cooling is divided into circulation gas 13 and second strand of first paragraph gas product 14, circulation gas 13 is through the 3rd heat-exchange equipment 15 coolings, obtain temperature and be the circulation gas 16 of 170 ~ 190 ℃, circulation gas 16 obtains the circulation gas 18 after supercharging through recycle compressor 17 superchargings, circulation gas 18 after supercharging heats up through the 3rd heat-exchange equipment 15, obtains temperature and be the circulation gas 19 after the supercharging of 290 ~ 310 ℃;
D) second strand of first paragraph gas product 14 and second strand of unstripped gas 5, second steam 38 being mixed to get to temperature is second gas mixture 20 of 290 ~ 310 ℃, the second gas mixture 20 is passed in second segment methanator 21 and reacted, obtain temperature and be the second segment gas product 22 of 640 ~ 660 ℃, this second segment gas product 22 is through the 4th heat-exchange equipment 23 coolings, obtain the second segment gas product 24 after the cooling of 480 ~ 500 ℃ of temperature, the second segment gas product 24 after cooling is cooled to 280 ~ 300 ℃ of second segment gas products 26 after being lowered the temperature through the 5th heat-exchange equipment 25;
E) the second segment gas product 26 after cooling and the 3rd strand of unstripped gas 6, the 3rd steam 39 being mixed to get to temperature is the 3rd gas mixture 27 of 280 ~ 300 ℃, the 3rd gas mixture 27 is passed in the 3rd section of methanator 28 and reacted, obtain temperature and be 29, the three sections of gas products 29 of the 3rd section of gas product of 480 ~ 500 ℃ the 3rd section of gas product 30 after the first heat-exchange equipment 2 is cooled to 80 ~ 100 ℃ of coolings that obtain;
F) the 3rd section of gas product 30 after cooling and the 4th strand of unstripped gas 7, the 4th steam 40 being mixed to get to temperature is the 4th gas mixture 31 of 70 ~ 90 ℃, described the 4th gas mixture 31 heats up through the 6th heat-exchange equipment 32, obtain temperature and be the 4th gas mixture 33 after the intensification of 250 ~ 270 ℃, the 4th gas mixture 33 after intensification passes in the 4th section of methanator 34 and reacts, and obtains temperature and be the 4th section of gas product 35 of 370 ~ 390 ℃;
G) the 4th section of gas product 35 being obtained after the 6th heat-exchange equipment 32 is lowered the temperature and carried out gas-liquid separation to temperature is the gas product 36 of 30 ~ 50 ℃.
Wherein, the technique of utilizing of methanation reaction heat release comprises: the oiler feed 41 from battery limit (BL) enters drum 42, the first oiler feed 43 from drum 42 enters the first saturation steam 44 that the second heat-exchange equipment 11 produces 3 ~ 10MPa, the second oiler feed 45 from drum 42 enters the second saturation steam 46 that the 4th heat-exchange equipment 23 produces 3 ~ 10MPa, from the 3rd saturation steam 47 of drum 42, through the 5th heat-exchange equipment 25, heat up, obtain temperature and be the superheated vapour 48 of 440 ~ 460 ℃.
Wherein, the volume ratio of first strand of unstripped gas 4, second strand of unstripped gas 5, the 3rd strand of unstripped gas 6 and the 4th strand of unstripped gas 7 is 1:0.41:0.04:0.01, and the volume ratio of circulation gas 13 and second strand of first paragraph gas product 14 is 1:0.54.
Below by the gas composition parameter of each logistics in table 3, a situation arises to have described intuitively the reality of each workshop section's methanation reaction in Fig. 1 technical process.
Table 3
The explanation of logistics numbering is with table 1.
comparative example 1
For contrasting with embodiment 1, under identical design basis condition, adopt low temperature methanation technology production synthetic natural gas in tradition, concrete technology schema is as shown in Figure 3.
A) coal or biomass are met the unstripped gas of requirement through gasification unit, converter unit and clean unit.Unstripped gas 1 〞 is warming up to unstripped gas 3 〞 after being heated up after 140 ~ 160 ℃ through the first heat-exchange equipment 2 〞.Unstripped gas 3 〞 after intensification are divided into three bursts of logistics, that is: first gang of unstripped gas 4 〞, second gang of unstripped gas 5 〞 and the 3rd unstripped gas 6 〞.
B) first gang of unstripped gas 4 〞 mixed with the first steam 32 〞, first gang of circulation gas 26 〞, obtain temperature and be first gas mixture 7 〞 of 270 ~ 290 ℃, passed in first paragraph methanator 8 〞 and carried out methanation reaction, obtained temperature and be first paragraph gas product 9 〞 of 490 ~ 510 ℃.First paragraph gas product 9 〞 are through the second heat-exchange equipment 10 〞 and the 3rd heat-exchange equipment 12 〞 coolings, obtain temperature and be first paragraph gas product 13 〞 after the cooling of 300 ~ 320 ℃, simultaneously by-product saturation steam and superheated vapour.
C) first paragraph gas product 13 〞 after cooling are mixed with second gang of unstripped gas 5 〞, the second steam 33 〞, second gang of circulation gas 27 〞, obtain temperature and be second gas mixture 14 〞 of 270 ~ 290 ℃, passed in second segment methanator 15 〞 and carried out methanation reaction, obtained temperature and be second segment gas product 16 〞 of 490 ~ 510 ℃.Second segment gas product 16 〞 are cooled to second segment gas product 18 〞 after being lowered the temperature after 230 ~ 250 ℃ through the 4th heat-exchange equipment 17 〞.
D) second segment gas product 18 〞 after cooling are divided into two strands: first gang of second segment gas product 19 〞 and second gang of second segment gas product 20 〞.First gang of second segment gas product 19 〞 are cooled to first gang of second segment gas product 22 〞 after being lowered the temperature after 30 ~ 50 ℃ through the 5th heat-exchange equipment 21 〞.First gang of second segment gas product 22 〞 after cooling enter recycle compressor 23 〞 superchargings, obtain circulation gas 24 〞, and loop compression acc power is 1651kW.Circulation gas 24 〞 heat up through the 5th heat-exchange equipment 21 〞, obtain temperature and be circulation gas 25 〞 after the intensification of 190 ~ 210 ℃.Circulation gas 25 〞 after heating up are divided into two strands, that is: first gang of circulation gas 26 〞 and second gang of circulation gas 27 〞.First gang of circulation gas 26 〞 and second gang of circulation gas 27 〞 enter respectively in first paragraph and second segment methanator and react.
E) second gang of second segment gas product 20 〞 mixes with the 3rd gang of unstripped gas 6 〞, the 3rd steam 34 〞, obtain temperature and be the 3rd gas mixture 28 〞 of 230 ~ 250 ℃, sent in the 3rd section of methanator 29 〞 and carried out methanation reaction, obtained temperature and be the 3rd section of gas product 30 〞 of 290 ~ 310 ℃.The 3rd section of gas product 30 〞 are through the first heat-exchange equipment 2 〞 coolings and after gas-liquid separation, to obtain temperature be gas product 31 〞 (SNG) of 30 ~ 50 ℃.
Wherein, the technique of utilizing of methanation reaction heat release comprises: oiler feed 35 〞 from battery limit (BL) send into drum 36 〞 after preheating, from the first oiler feed 37 〞 in drum 36 〞 with the second oiler feed 39 〞 enter respectively the 3rd heat-exchange equipment 12 〞 by downtake and the 4th heat-exchange equipment 17 〞 produce the first saturation steam 38 〞 and the second saturation steam 40 〞, the first saturation steam 38 〞 and the second saturation steam 40 〞 enter drum 36 〞 through riser, the 3rd saturation steam 41 〞 that drum 36 〞 produce heat up through the second heat-exchange equipment 10 〞, superheated vapour 42 〞 that obtain temperature and be 440 ~ 460 ℃ send battery limit (BL).
Wherein, the volume ratio of first gang of unstripped gas 4 〞, second gang of unstripped gas 5 〞, the 3rd gang of unstripped gas 6 〞 is 1:1.30:0.02, the volume ratio of first gang of second segment gas product 19 〞 and second gang of second segment gas product 20 〞 is 1:0.25, and the volume ratio of first gang of circulation gas 26 〞 and second gang of circulation gas 27 〞 is 1:0.05.
Below by the gas composition parameter of each logistics in table 4, a situation arises to have described intuitively the reality of each workshop section's methanation reaction in the technical process shown in Fig. 3.
Table 4
The explanation of logistics numbering: 1 〞 is unstripped gas; 7 〞 are the first gas mixture; 9 〞 are first paragraph gas product; 14 〞 are the second gas mixture; 16 〞 are second segment gas product; 28 〞 are the 3rd gas mixture; 30 〞 are the 3rd section of gas product; 22 〞 are circulation gas; 31 〞 are gas product SNG; 42 〞 are superheated vapour.
Compare with comparative example 1, under identical design basis, embodiment 1 is higher than heat utilization ratio, it is low to consume: embodiment 1 loop compression acc power is 896kW, and comparative example 1 is 1115kW, and the energy consumption of embodiment 1 is lower by 19.6% than comparative example 1; Embodiment 1 by-product superheated vapour 171.2t/h, comparative example 1 by-product superheated vapour 158.6t/h, the by-product superheated vapour amount of embodiment 1 is higher by 7.9% than comparative example 1.To sum up, can illustrate that the method capacity usage ratio of production synthetic natural gas provided by the invention is high, consume low.