Method for hydrothermally reducing CO2 or CO into methane by using porous nickel catalyst

Abstract

The invention relates to a method for hydrothermally reducing CO2 or CO into methane by using a porous nickel catalyst. The method comprises the following steps of: placing the porous nickel catalyst into a hydrothermal reactor, mixing hydrogen and CO2 or CO according to the molar ratio of 1:(1-10) in the hydrothermal reactor, controlling the temperature of the reactor to 200 to 400 DEG C, and adjusting the pressure of the reactor to 6 to 20MPa and the reaction time to 5 to 180 minutes to obtain the reaction product, namely methane. When the method is compared with the prior art, the highest conversion rate of CO2 and CO is 99 percent, the whole reaction is performed under a hydrothermal condition, the defect that the catalyst is inactivated because carbon is easy to accumulate on the surface of the catalyst in a gas-phase reduction process is overcome, and the used catalyst has the characteristics of high strength, good activity, good thermal stability, excellent low-temperature activity and the like.

Description

technical field [0001] The invention relates to the technical field of environmental engineering, in particular to a method for hydrothermally reducing CO using a porous nickel catalyst. 2 method for methane. Background technique [0002] Since the 1930s, human use of fossil fuels has emitted large amounts of CO 2 Greenhouse gases such as CO in the atmosphere 2 The problem of continuous increase in concentration has attracted great attention from governments of various countries. How to limit CO 2 Excessive emissions have become a global issue for the sustainable development of countries. Therefore from CO 2 The conversion technology from chemical to chemical has attracted the attention of countries all over the world and has begun to be put into practical application. At present, technological achievements at different development stages have been produced, such as the utilization of CO with the direct or indirect participation of other chemical substances 2 The techn...

AI Technical Summary

Problems solved by technology

First, the semiconductor-based colloidal catalytic system and noble metal complex solution catalytic system have the disadvantages of low catalytic efficiency and low quantum yield, and the high cost of such catalysts is not conducive to industrial applications

The second is that mercury lamps are mostly used to simulate sunlight in laboratory research, but the actual sunlight is more dispersed than mercury lamp radiation, so the reaction device needs to have a large light-receiving area to gather sunlight on a large scale, which will inevitably increase the cost

Although the gas-phase reduction of carbon dioxide has been widely used in industry at present, there are still some problems in this method, which are embodied in: (1) when the CO content in the feed gas>0.3%, (CO+CO 2 )>0.7%, it is easy to cause the catalyst bed temperature to fluctuate, and it is difficult to control the temperature accurately

(2) The methanation reaction is carried out in the gas phase, which is prone to carbon deposition, resulting in catalyst deactivation and lower conversion efficiency

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