Circulating method for preparing natural gas by multi-stage methanation of semi-coke tail gas

A technology of semi-coke tail gas and methanation, which is applied in the field of using semi-coke tail gas to produce natural gas, can solve the problem of low balance conversion rate, achieve the effect of reducing heat resistance requirements and prolonging service life

Active Publication Date: 2012-11-14
SOUTHWEST RES & DESIGN INST OF CHEM IND
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

With increasing temperature, CO and CO 2 The balance conversion rate of

Method used

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  • Circulating method for preparing natural gas by multi-stage methanation of semi-coke tail gas
  • Circulating method for preparing natural gas by multi-stage methanation of semi-coke tail gas
  • Circulating method for preparing natural gas by multi-stage methanation of semi-coke tail gas

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] like figure 1 As shown, the main composition (volume percentage) of semi-coke tail gas after purification and adjustment of hydrogen-carbon ratio is as follows: H 2 : 38.22, CH 4 : 7.87, CO: 8.61, CO 2 : 3.86, C n h m : 0.53, N 2: 40.91, gas volume 1000kmol, pressure 2.1MPa, temperature 40°C.

[0037] Front-end methanation part: first and second methanation furnaces R1, R2; back-stage methanation part: third methanation furnace R3. The feed gas is preheated to 250-300°C and then divided into two streams. The first stream has a volume of 450 kmol. It is mixed with steam and recycled reaction gas and enters the first methanation furnace R1 for reaction. Among them, the volume ratio of water vapor to reaction gas is 0.18, the circulation ratio (i.e. the ratio of circulation gas to total inlet gas volume, the same below) is 0.5, the temperature of raw material gas entering the first methanation furnace R1 is not lower than 260°C, and the outlet temperature is about ...

Embodiment 2

[0040] like figure 2 As shown, the main composition (volume percentage) of semi-coke tail gas after purification and adjustment of hydrogen-carbon ratio is as follows: H 2 : 38.22, CH 4 : 7.87, CO: 8.61, CO 2 : 3.86, C n h m : 0.53, N 2 : 40.91, gas volume 1000kmol, pressure 2.1MPa, temperature 40°C.

[0041] Front-end methanation part: first and second methanation furnaces R1 and R2; back-stage methanation part: third and fourth methanation furnaces R3 and R4. The feed gas is preheated to 250-300°C and then divided into two streams. The first stream has a volume of 420 kmol. It is mixed with steam and recycled reaction gas and enters the first methanation furnace R1 for reaction. The volume ratio of water vapor to reaction gas is 0.05, the circulation ratio of circulating gas is 0.65, the temperature of raw material gas entering the first methanation furnace R1 is not lower than 260°C, and the outlet temperature is about 463°C. The gas at the outlet of the first metha...

Embodiment 3

[0045] like image 3 As shown, the main composition (volume percentage) of semi-coke tail gas after purification and adjustment of hydrogen-carbon ratio is as follows: H 2 : 38.22, CH 4 : 7.87, CO: 8.61, CO 2 : 3.86, C n h m : 0.53, N 2 : 40.91, gas volume 1000kmol, pressure 2.1MPa, temperature 40°C.

[0046] Front-end methanation part: first, second and third methanation furnaces R1, R2, R3; back-stage methanation part: fourth and fifth methanation furnaces R4 and R5. The feed gas is preheated to 250-300°C and divided into three streams. The first stream has a volume of 250 kmol. It is mixed with steam and recycled reaction gas and enters the first methanation furnace R1 for reaction. The volume ratio of water vapor to reaction gas is 0.13, the circulation ratio of circulating gas is 0.6, the temperature of raw material gas entering the first methanation furnace R1 is not lower than 260°C, and the outlet temperature is about 469°C. The gas at the outlet of the first me...

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Abstract

The invention discloses a circulating method for producing a natural gas by multi-stage methanation of semi-coke tail gas, and belongs to the field of preparation methods of natural gas. The preparation method comprises the following steps that: the purified semi-coke tail gas the hydrogen to carbon ratio of which is adjusted is used as a raw material, and the multi-stage methanation reaction is adopted to obtain a methane-rich gas; a front-end methanation part and a back-section methanation part are comprised, wherein the front-end methanation part is formed by connecting at least two methanation furnaces in series, and the back-section methanation part is formed by connecting more than one methanation furnace in series; and the obtained methane-rich gas is separated to obtain a product natural gas. The methanation process has strong controllability, the temperature of the methanation reaction can be controlled by adjusting the recycle gas, the raw material inlet temperature and the steam addition amount and other ways, and the temperature of the methanation reaction is controlled below 500 DEG C. The lower methanation operating temperature is not only favorable for performing the methanation reaction, reduces the requirements of the process on a material of a reactor and heat resistance of a catalyst, but also is favorable for prolonging the service life of the methanation reactor and the catalyst.

Description

technical field [0001] The invention belongs to the field of natural gas preparation methods, and in particular relates to a method for preparing natural gas by using semi-coke tail gas. Background technique [0002] Semi-coke, also known as semi-coke, is a solid substance with high fixed carbon content produced by using Jurassic non-caking coal and weakly caking coal as raw materials by medium and low temperature dry distillation process, because it produces blue flame when burning name. During the production of semi-coke, semi-coke tail gas and coal tar are produced as by-products. At present, about 700Nm of semi-coke is produced per ton of semi-coke 3 The exhaust gas has a calorific value of 1700-2000 kcal. In 2010, the national semi-coke production was about 10 million tons, that is, the by-product semi-coke tail gas was about 7 billion Nm 3 . During the 12th Five-Year Plan period, my country's semi-coke market is expected to reach more than 50 million tons per year,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C10L3/08
Inventor 易竖棚李泽军郭雄谭青
Owner SOUTHWEST RES & DESIGN INST OF CHEM IND
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