Process and device of fluidized bed for synthesis gas methanation

Abstract

The invention relates to a process and a device of a fluidized bed for synthesis gas methanation and belongs to the technical field of coal natural gas. The process includes first preheating raw material gas composed of H2 and CO, introducing the preheated gas from the bottom of a fluidized bed reactor in a magnetic field, enabling the raw material gas to be completely contacted with catalyst particles for reaction, conducting separation on mixture of gas products and a small amount of catalyst fine powder through a cyclone separator and conducting following processing to obtain purified methane. The device is composed of a fluidized bed reactor and auxiliary devices including a magnetic field generator, a current stabilizing power supply controller, a mass flow meter and the like which are sleeved on the outer portion of the fluidized bed. The process and the device enable the catalyst particles to form a magnetic stable bed by cooperative control of an external magnetic field and gas flow speed under the effect of the magnetic field, prevent catalyst particle from bonding flow loss, improve fluidization quality, strengthen gas-solid heat transfer and mass transfer, are small in temperature difference in a bed layer, improve carbon monoxide conversion rate and methane selectivity, simultaneously can prevent the catalyst particles from being brought out of the fluidized bed reactor by gas and reduce catalyst loss.

Description

technical field [0001] The invention relates to the technical field of coal-to-natural gas, in particular to a fluidized bed process and device for syngas methanation. Background technique [0002] Since the global oil crisis broke out in the 1970s, the research on coal-to-synthetic natural gas has attracted extensive attention from researchers at home and abroad. The basic process of the coal-to-synthetic natural gas process is high-temperature gasification of coal to generate synthesis gas (CO+H 2 ), the syngas adjusts H through water vapor shift 2 When the molar ratio with CO reaches an appropriate value, the sulfur is eluted with methanol, the methanation reaction is carried out in a multi-stage fixed-bed adiabatic reactor, and the tail gas is condensed and purified. Syngas methanation is a key part of the above process, the core of which is a methanation catalyst and an adiabatic fixed-bed reactor. [0003] Syngas methanation reaction It is a strong exothermic reac...

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Problems solved by technology

CN1960954A discloses a method for syngas fluidized bed methanation, the reaction temperature is 200~500°C, and the volume space velocity is 1000~50000h -1 , but no methanation yield and conversion

CN102180757A discloses a channel-type circulating fluidized bed reactor for methanation reaction. The core is to coat Ni-based methanation catalyst on the wall of the channel reactor, and the synthesis gas carries adsorbents CaO and MgO into the channel reactor for full contact reaction, but from the perspective of product composition, the volume fraction of methane is 71-90%, and the volume fraction of CO is 3.8-15.8%, and the conversion rate of CO is slightly lower

However, due to the strong gas back-mixing in the fluidized bed will affect the conversion rate of the methanation reaction, and there are problems such as catalyst wear and carry-over loss, the fluidized bed methanation process is still in the laboratory development stage and has not yet been industrialized. Complete Methanation Fluidized Bed Process

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