The invention belongs to the field of chemical industry and in particular relates to a non-circulating methanation process of coal-based synthetic natural gas and liquefied natural gas. The process comprises the following concrete steps: introducing coal-based synthetic gas subjected to sulfur-tolerant shift and low-temperature methanol elution desulfurization and decarbonization into an ultra-precision purifier; enabling the total sulfur content to be less than 0.02 ppm, the chlorine content to be less than 0.01 ppm and the heavy metal content to be less than 0.01 ppm in the synthetic gas entering the methanation process; dividing the synthetic gas into three, four or five parts; enabling the synthetic gas parts to enter main methanation reactors respectively; enabling all gas at the outlet of the final main methanation reactor to enter auxiliary methanation reactors for continuous methanation reaction in sequence; cooling and dehydrating to obtain the synthetic natural gas (SNG) meeting the requirements, or adding a cryogenic separation liquefication process to obtain the liquefied natural gas (LNG). The process has the advantages of no circulating compressor, low investment, high energy utilization rate and low running expense.

Non-circulating methanation process of coal-based synthetic natural gas and liquefied natural gas

The invention discloses a synthetic natural gas prepared from one-step process coal and a system thereof. The synthetic natural gas is prepared by the following steps: H2S and other impurities are removed from normal-temperature crude coal gas to obtain purified gas; the purified gas is preheated, subjected to removal of sulfur and other impurities, and divided into two streams; the first purified gas stream enters a thermal-insulation methanation reactor to perform methanation reaction; the reaction gas from the thermal-insulation methanation reactor is cooled by a steam superheater, and sent into an isothermal methanation reactor together with the second purified gas stream; the reaction gas from the isothermal methanation reactor is divided into two streams; the first reaction gas stream is cooled, pressurized by a recycle gas compressor, and sent into the thermal-insulation methanation reactor together with the first purified gas stream; and the second reaction gas stream is cooled, subjected to condensate separation by a condensate separator, and sent into a second absorption tower of a low-temperature methanol washer to remove CO2 and water, thereby obtaining the synthetic natural gas. The method has the advantages of simple technique, brief process, and low device operation and investment cost, and can centrally recover heat energy and coproduce high-quality steam.

Synthetic natural gas prepared from one-step process coal and system thereof

The invention belongs to the chemical engineering field, and specifically relates to a coal syngas circulation gas free methanation technology. The technology firstly divides a methanation reactor into two parts, the purified raw material gas is divided into a plurality of gas flows, then the gas flows is introduced into the front methanation reactor, wherein parts of the front methanation reactor are connected through a combination mode of serial connection and parallel connection; the gas in the each level of methanation reactors in the front part goes out from the outlet of the first reactor and the outlet is serially connected to other level methanation reactors, or the gas is divided into a plurality of gas flows and enters other level reactors which are connected through a combination mode of serial connection and parallel connection. The technology adopts water steam as the diluting gas for diluting the raw material gas in a methanation reactor, the water steam is mainly applied to the high temperature methanation reaction technology, the pressure of the by-product namely steam is larger than the methanation reaction pressure, and thus the steam can be directly added into the raw material gas in a methanation reactor. The technology does not need a circulation gas compressor, so the production cost is reduced. Because the methanation reaction is a strong heat dissipation reaction, the added water stream is reduced so as to improve the energy utilization rate.

Coal syngas circulation gas free methanation technology

The invention provides a sulfur-tolerant methanation process for preparing natural gases from synthesis gases. The sulfur-tolerant methanation process comprises the steps that after hydrogen is replenished to the synthesis gases to form feed gases, the feed gases are compressed, a part of the feed gases enter a sulfur-tolerant slurry bed reactor from the bottom of a slurry bed reactor containing an inert medium and a sulfur-tolerant methanation catalyst to undergo methanation reaction, the product gases are exhausted from the top of the slurry bed reactor and enter a gas-liquid-solid separator, the liquid and solid phases are discharged from the bottom of the separator and flow back to the slurry bed reactor, the gas phase is discharged from the top of the separator, the separated gas phase and the other part of the feed gases flowing along the lateral line enter a fixed bed sulfur-tolerant methanation reactor from the bottom of a fixed bed containing a sulfur-tolerant catalyst to undergo sulfur-tolerant methanation, the product gases are exhausted from the top and undergo heat exchange in a heat recovery device and the qualified natural gas products are obtained through purification. The sulfur-tolerant methanation process has the advantages of high energy utilization rate, low equipment investment and operating cost and easiness in operation.

Sulfur-tolerant methanation process for preparing natural gases from synthesis gases

The invention relates to a methanation device and process for synthesizing high-quality natural gas produced by coal. The methanation device is a multi-grade circulation external heat-transfer methanation device and is characterized in that a first grade device is a primary methanation device and a second grade device is an auxiliary methanation device; the primary methanation device and the auxiliary methanation device are connected; a gas circulating system is arranged between the primary methanation device and the auxiliary methanation device; the methanation device further comprises a heat recycling system; the primary methanation device is used for introducing a raw material gas; the auxiliary methanation device is used for introducing carbon dioxide; the methanation process is mainly used for adding a carbon dioxide gas in a working section of the auxiliary methanation device without increasing the thermal load of a primary methanation process; the system is easy to control, the methane product is high, the whole methanation process is guaranteed to be lightly affected by the front process, and the product quality is stable.

Methanation device and process for synthesizing high-quality natural gas produced by coal

Methanation technology for preparing non-recycling gas of SNG or LNG from coke-oven gas

Novel methanation reaction process for preparing synthetic natural gas

The invention discloses a process for preparing liquefied natural gas (LNG) from coal. The process is specifically characterized in that only fine desulfurization is needed before methanation of synthetic gas from coal, CO2 still stays in the synthetic gas, CO2 is removed after methanation, and the synthetic gas is liquefied till the CO2 is 50*10 (vol%) to produce the LNG. The methanation process without recycle gas is adopted, and CO2 is removed by combining low-temperature separation with low-temperature methanol washing phase. CO2 is separated at the temperature of -50 to -60 DEG C under the pressure of 2.4-2.6MPa, and liquid pure CO2 obtained at a column reactor is used as a byproduct. Mixed gas of CH4 and CO2 is obtained at the tower top and delivered to a low-temperature methanol washing tower, and CO2 is removed to 50*10 (vol%). By adopting the process, CO2 can be conveniently collected as a byproduct. Meanwhile, the gas quantity of low-temperature methanol washing and the CO2 quantity are reduced. For the conventional coal-made SNG (synthetic natural gas) process, the quantity of recycle gas can be reduced by more than 50% by adopting the process.

Process for preparing liquefied natural gas (LNG) from coal

The invention discloses a CO2 high-temperature methanation catalyst and particularly discloses a high-concentration CO2 methanation catalyst, which belongs to the technical field of catalysts. The CO2 high-temperature methanation catalyst comprises a carrier, an active component and auxiliaries, wherein the active component is nickel oxide and the auxiliaries comprise aluminum oxide, lanthanum oxide and chromic oxide. Specifically, the components are as follows in parts: 20-40 parts of the carrier, 40-60 parts of nickel oxide, 15-25 parts of aluminum oxide, 2-4 parts of lanthanum oxide and 1-3 parts of chromic oxide. The CO2 high-temperature methanation catalyst disclosed by the invention is high in mechanical strength and good in heat stability and shows excellent activity in methanation reaction of CO2. The catalyst is suitable for methanation reaction of gas components with relatively high content of CO2 in synthesis gas from coal and can be further used in the field of CO2 emission reduction.

Zheng Heng

Papers

Methanation technology for preparing non-recycling gas of SNG or LNG from coke-oven gas

Novel methanation reaction process for preparing synthetic natural gas

Non-circulating methanation process of coal-based synthetic natural gas and liquefied natural gas

Process for preparing liquefied natural gas (LNG) from coal

CO2 high-temperature methanation catalyst, and preparation and use methods thereof