Low-temperature methanation catalyst and preparation method thereof

Abstract

The invention discloses a low-temperature methanation catalyst and a preparation method thereof. The low-temperature methanation catalyst comprises an active component, a surfactant, a structural auxiliary agent and a cocatalyst, wherein the active component is Ni; the structure auxiliary agent is a composite structure auxiliary agent composed of Al2O3 and diatomite; the cocatalyst is one or two of La2O3, MgO, CuO and MnO; the content of the active component accounts for 50%-75% of the total mass of the low-temperature methanation catalyst, and the content of the cocatalyst accounts for 0.4%-0.8% of the total mass of the low-temperature methanation catalyst. The method is lower in reaction temperature, lower in energy consumption and simple to operate, has high catalytic activity and longservice life in a low-temperature environment, and can realize efficient catalytic conversion of CO and CO2.

Description

technical field [0001] The invention relates to the field of methanation catalysts, in particular to a low-temperature methanation catalyst and a preparation method thereof. Background technique [0002] Crude hydrogen gas in ethylene industrial plants and ammonia plants inevitably contains CO and CO 2 Components whose presence can be toxic to downstream devices must be cleaned. At present, the most economical and efficient method of purifying hydrogen is methanation, that is, through CO, CO 2 React with a small amount of hydrogen to form inert CH 4 to remove CO and CO from the gas 2 . [0003] CO and CO are inevitably contained in the hydrogen-rich gas separated from the hydrogen / methane separation tank in the hydrogen / methane separation tank of the ethylene production plant by cracking naphtha and light hydrocarbons 2 , and this part H 2 It is the raw material for the downstream hydrogenation process, and if the CO is not removed, it will cause catalyst poisoning and...

AI Technical Summary

Problems solved by technology

[0005] At present, domestic low-temperature methanation technology is not mature enough, so it is necessary to develop a low-temperature methanation catalyst

Chinese patent application CN108479844A discloses a nickel-based catalyst for CO low-temperature selective methanation and its preparation method and application. The catalyst uses metal Ni as the active component and Zr-doped mesoporous molecular sieve Zr#SBA#16 as the carrier Supported catalyst, although the invented nickel-based catalyst can deeply remove CO in hydrogen-rich reformed gas to below 10ppm at a relatively low temperature (180-230°C), and at the same time, the selectivity of CO methanation reaction is higher than 50% , but the cost of mesoporous molecular sieves is high, the stability is insufficient, and the catalyst activity is slightly low

Chinese patent application CN107376925B provides a low-temperature high-activity carbon dioxide methanation catalyst and its preparation method, using CO(NH 2 ) 2 instead of NaOH and Na 2 CO, through slow hydrolysis at 90-120°C, provides OH needed for precipitation - and CO 2- Generate a uniform [Ni 1-x 2+ Al x 3+ (OH) 2 ] x+ (CO 3 ) x / 2 2- Precipitation, the catalyst starts to activate at around 150°C to 250°C, and reaches more than 90% CO at 260°C to 400°C 2 conversion and nearly 100% CH 4 selectivity, and has good hydrothermal stability, but the preparation process CO(NH 2 ) 2 Incomplete decomposition will easily lead to high nitrogen content in the aqueous solution and high cost of environmental protection treatment

Chinese patent application CN104511314A discloses a low-temperature methanation catalyst, which includes: an organic polymer material carrier, Raney alloy particles loaded on the surface of the organic polymer material carrier, and the Raney alloy contains 30-60wt% nickel, 0.01-5wt% of iron, 0.01-5wt% of chromium, 0.01-5wt% of lanthanum and 30-60wt% of aluminum, the catalyst has the advantages of high activity in low temperature methanation reaction, but the cost of polymer carrier is high

Existing methanation catalysts have problems such as high reaction temperature, high energy consumption, and difficult operation. Therefore, it is necessary to develop a low-temperature methanation catalyst that can maintain high activity and long life in a low-temperature environment to replace high-temperature methanation catalysts. catalyst