Synthetic natural gas production using a carbon resistant, promoted supported catalyst

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This invention describes a method for producing synthetic natural gas (SNG) from gas mixtures containing carbon monoxide (CO) and/or carbon dioxide (CO2), especially those generated from industrial processes such as biomass gasification, pyrolysis, or fermentation. The key feature is a specialized catalyst consisting of nickel (possibly with other metals), promoted by boron (and optionally other elements), and supported on materials like alumina. This catalyst is highly resistant to carbon formation and deactivation, particularly at low temperatures (200-500°C), leading to improved efficiency and longevity in methane production from challenging feed gases that also contain unsaturated hydrocarbons.

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• Industrial production of synthetic natural gas from biomass, coal, or other carbonaceous feedstocks via gasification or pyrolysis.
• Upgrading biogas or syngas with high CO and hydrocarbon content into methane-rich SNG for use as fuel in natural gas grids.
• Efficient conversion of carbon-rich or mixed waste gases from fermentation, ore conversion, or combustion processes into usable methane.
• Application in 'Power-to-Gas' systems to store excess renewable electricity by converting biogas to synthetic natural gas.
• Use in chemical plants where long catalyst life and resistance to coke formation are critical for profitability and process reliability.

BenefitsContent extracted from patent full text and abstract with AI.

• Significantly increases the lifetime of nickel catalysts by resisting deactivation due to carbon (coke) formation, particularly in feeds rich in olefins and tars.
• Enables efficient SNG production at lower temperatures, which can save energy and reduce operational costs.
• Reduces the need for expensive gas purification steps prior to methanation, increasing economic viability with real-world, less pure gas feeds.
• Low-cost and easily scalable catalyst preparation using abundant metals and simple impregnation methods.
• Potential to improve the overall efficiency and reliability of renewable gas production processes.

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Patent Abstract

It is therefore the objective of the present invention to provide a method for the production of SNG taking advantage from a catalyst which has a high selectivity for the catalytic reactions and achieves long lifetime of the catalyst due to minor clogging and strong carbon resistance to prevent its deactivation. These objectives are achieved according to the present invention by a method to convert a CO and/or CO 2 comprising a gas mixture stemming from an industrial processes, such as gasification of carbonaceous feedstocks (i.e. biomass), pyrolysis, ore conversion, combustion, calcination or fermentation, wherein the gas mixture further comprises saturated hydrocarbons in concentrations above 15% and/or unsaturated hydrocarbons, such as olefins, tars and/or aromatic compounds, into a methane rich gas by bringing the gas mixture into a contact with a supported metal catalyst comprising: a) as an active phase nickel and optionally cobalt, ruthenium, iridium, molybdenum, iron or any possible combination thereof, b) as a promoter boron and optionally sodium, potassium, calcium, magnesium, boron, rubidium, barium, gallium, phosphorus or any possible combinations thereof, and c) as a support alumina and optionally silica, titania, lanthana, zirconia, ceria, magnesia or any possible combination thereof. The presented invention improves the carbon resistance of nickel catalysts for low temperature (250-400°C) applications such as the methanation. Polymeric carbon is formed by reaction of carbon atoms on the catalyst surface under locally hydrogen-deficient situations. These carbon atoms stem from dissociation of carbon oxides and hydrocarbons whereby unsaturated hydrocarbons (ethylene, acetylene) and CO lead to higher carbon deposition rates. Using presently the promoter boron in the nickel catalyst avoids the formation of intermediates for polymeric carbon. As a second benefit, the formation of nickel carbides and carbon whiskers is decreased, too.