The invention relates to a method of producing substitute natural gas by methanation of synthesis gas, mainly solving problems, namely large using amount of recycle gas and high energy consumption of compressors, of high-temperature methanation reactions in the prior art. According to the technical scheme adopted by the method, the method comprises: a) a step of providing a high-temperature methanation reaction zone including n-stage series-connected reactors, with the n being not less than 2; b) a step of dividing the synthesis gas raw materials containing H2, CO, CO2 and H2O into n sections and respectively feeding the n sections of the synthesis gas raw materials into inlets of the reactors at all stages in the high-temperature methanation reaction zone, wherein a stream flowing out of an outlet of each of the reactors except the reactor at the final stage enters the inlet of the reactor at the next stage, the stream Vn flowing out from the reactor at the final stage is divided into Vn' and Vn'', and the stream Vn' is condensed and circulated to the inlet of the reactor at the first stage; c) a step of providing a low-temperature methanation reaction zone including m-stage series-connected reactors, with the m being not less than 2; and d) a step of feeding the stream Vn'' into the low-temperature methanation reaction zone, and substitute natural gas is obtained after the reaction. By the technical scheme, the problems are solved well and the method can be used in industrial production of the substitute natural gas from the synthesis gas.

Method of producing substitute natural gas by methanation of synthesis gas

The invention relates to a method of producing substitute natural gas from synthesis gas, mainly solving problems, namely large using amount of recycle gas, high energy consumption of compressors and short service lifetime of catalysts, of high-temperature methanation reactions in the prior art. According to the technical scheme adopted by the method, the method comprises: a) a step of providing a high-temperature methanation reaction zone including n-stage series-connected reactors, wherein the n is not less than 2, each reactor is divided into m sections of catalyst layers and the m is not less than 2; b) a step of dividing the synthesis gas raw materials into n sections and respectively feeding the n sections of the synthesis gas raw materials into inlets of the reactors at all stages in the high-temperature methanation reaction zone, wherein each section of the synthesis gas raw materials that enters a reactor is then divided into m streams and the m streams respectively enter the corresponding catalyst layers; c) a step of allowing a stream flowing out of an outlet of each of the reactors except the reactor at the final stage to enter the first section of catalyst layer in the reactor at the next stage; and d) a step of shunting the stream Vn flowing out from the reactor at the final stage to obtain a part Vn', and circulating the stream Vn' after the Vn' is condensed to the inlet of the reactor at the first stage. By the technical scheme, the problems are solved well and the method can be used in industrial production of substitute natural gas from synthesis gas.

Method of producing substitute natural gas from synthesis gas

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

System and method for preparing alternative 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 discloses a methanation process of synthetic natural gas prepared from coal. Purified and decarbonized synthetic gas prepared from coal is divided into three parts, wherein the first part of the synthetic gas is fed into a first methanation reactor after being mixed with recycle air; gas at the outlet of the first methanation reactor is fed into a second methanation reactor after being mixed with the second part of the synthetic gas; gas at the outlet of the second methanation reactor is fed into a third methanation reactor after being mixed with the third part of the synthetic gas; after the gas is cooled in the third methanation reactor, a part of the gas is fed into a recycle compressor, boosted and used as the recycle gas, and the rest of the gas is sequentially fed into a fourth methanation reactor, a fifth methanation reactor or a sixth methanation reactor to be subjected to methanation; the dry basis content of methane in the gas at the outlet of the final methanation reactor is larger than 95%; and then the synthetic natural gas (SNG) meeting requirements is obtained through cooling, compressing and dehydrating. The methanation process has the advantages of small recycle gas quantity, high energy utilization rates and saved investment.

A methanation process of synthetic natural gas prepared from 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 methanation catalyst for a fluidized bed and a preparation method of the methanation catalyst for the fluidized bed. The methanation catalyst for the fluidized bed comprises a carrier, an active component and auxiliary agents, and the active component and the auxiliary agents are loaded on the carrier. The carrier is a compound of Al2O3, ZrO2 and NiO or a compound of Al2O3, TiO2 and NiO; the active component is NiO; the auxiliary agents are oxides of at least one of Mg, Ca, La, Ce, Mn, Fe, Cu, Cr and Co. A co-precipitation method is adopted for preparation of the carrier of the catalyst, and uniformity in component distribution is realized; then spray forming is adopted to obtain the micro-spherical catalyst carrier which is high in fluidity and suitable for the fluidized bed. In preparation of the carrier of the catalyst, silicon sol or silicon-aluminum composite sol is added to serve as an adhesive; in a process of quick preparation of the micro-spherical carrier by spray forming, the silicon sol or silicon-aluminum composite sol is dispersed among carrier components, and after high-temperature calcination, the catalyst carrier is high in mechanical strength, abrasion resistance and impact resistance.

Methanation catalyst for fluidized bed and preparation method of methanation catalyst for fluidized bed

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.

Zhang Yu

Papers

A methanation process of synthetic natural gas prepared from 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

Methanation catalyst for fluidized bed and preparation method of methanation catalyst for fluidized bed

Coal syngas circulation gas free methanation technology