In-situ metal-doped mesoporous molecular sieves and their uses

Abstract

The invention relates to a mesoporous molecular sieve of doped metal and an application thereof. The mesoporous molecular sieve is formed by mixing a template, an alkali source, a silicon source and a metal source at the molar ratio of (0.06-0.24):(0.1-0.3):1:(0.01-0.20), and stirring at 20-40 DEG C for 0.5-24 hours to obtain emulsion; carrying out hydrothermal reaction on the emulsion at 80-180 DEG C for at least 12 hours (or reacting in a microwave reactor at the power of 200-2100w for 1-10h), then successively cooling, filtering, washing to be neutral and drying to obtain solid matters; and roasting the solid matters at 400-800 DEG C for 1-15 hours to obtain the molecular sieve, wherein the molecular sieve has a specific area of (BET)200-1500m2 / g, pore volume of 0.5-3.0cm3 / g and aperture of 2-15nm. The mesoporous molecular sieve has catalytic activity at 200-550 DEG C and the catalytic activity does not decline after roasting at 700 DEG C for 20 hours. The molecular sieve can be used as a catalyst for reaction during methane preparation by synthesis gas, and has commercial value.

Description

technical field [0001] The present invention relates to a metal-doped mesoporous molecular sieve and its application, in particular to a mesoporous molecular sieve doped with metal nickel in situ, or a mixture composed of metal nickel and alkali metal, rare earth elements and / or rare metals. Porous molecular sieves and their uses. Background technique [0002] The preparation of methane from synthesis gas (mixed gas of hydrogen and carbon monoxide) (hereinafter referred to as "carbon monoxide methanation reaction") is one of the main reactions of coal-to-natural gas, which is a strongly exothermic reaction (reaction heat can reach 20 of the calorific value of synthesis gas %about). A strong exothermic reaction will lead to a substantial increase in the temperature of the reaction gas, which will easily cause the sintering of the active components of the catalyst. Therefore, an excellent catalyst for "carbon monoxide methanation reaction" needs to have high activity and hig...

AI Technical Summary

Problems solved by technology

[0003] CN101185892A discloses a kind of Ni / ZrO 2 Catalyst, which can reduce the carbon monoxide (CO) content in the hydrogen-rich system to below 100ppm, but it is not suitable for the methanation reaction of synthesis gas with high CO concentration; CN101371987A discloses a Ni-Ru-B-ZrO 2 Catalyst, which can reduce the CO outlet concentration in the hydrogen-rich system to less than 22ppm, while maintaining extremely low carbon dioxide (CO 2 ) methanation rate

But it is only suitable for the atmosphere of hydrogen-rich system, that is, the concentration of CO should be very low, and it is not suitable for the atmosphere system of producing methane from high-concentration synthesis gas, and the applicable temperature of the catalyst is 210-250 ° C, which is not suitable for Carry out methanation reaction under high temperature condition; CN101468311A has reported a kind of with Ni as the main active component, with rare earth metal (La) as the first additive, Sr as the main and at least one of Cr, V, W, Mo as the second A catalyst for the "carbon monoxide methanation reaction" with a layered structure of two additives. The catalyst operates at a reaction temperature of 360°C and a space velocity of 3000h -1 , When the pressure is 2.5MPa, the CO conversion rate is 94.1%, and the methane selectivity is 97.5%, but this patent document does not provide the catalyst activity evaluation data of the catalyst at a higher space velocity and a higher reaction temperature; US Patent No. 3,787,468 provides Suitable for CO and CO 2 Methanation catalyst (Ru-WO x and Pt-Ru-WO x ), the main active component of the catalyst is Ru, and the content of Pt is 0-50% of Ru, WO x The content is 5-20% of Ru

The disadvantage of this catalyst is that its precious metal content is too high, resulting in increased production costs

Images