Process for Catalytic Supercritical Water Gasification Equipped with Several Sulfur Removal Steps

Simple SummaryContent extracted from patent full text and abstract with AI.

This invention describes a process for producing methane-rich gas from wet biomass or waste using catalytic supercritical water gasification. The key improvement is a multi-stage sulfur removal strategy: the feed is treated sequentially with specialized sulfur traps made from metal oxide and metal chalcogenide (sometimes carbon-hybrid) materials. These steps efficiently remove inorganic and organic sulfur compounds before the gasification reactor, protecting the expensive catalyst from sulfur poisoning and greatly extending its lifetime.

Use CasesContent extracted from patent full text and abstract with AI.

• Conversion of sewage sludge, food waste, or agricultural biomass into renewable methane (bio-methane) for energy production.
• Treatment and valorization of high-moisture industrial or municipal wastes to produce cleaner fuel gas.
• Implementation in waste-to-energy plants to increase the efficiency and longevity of gasification reactors.
• Biogas upgrading processes where minimizing catalyst poisoning is essential for stable operation.
• Decentralized or modular systems for sustainable biogas production from wet organic residues.

BenefitsContent extracted from patent full text and abstract with AI.

• Significantly improves catalyst lifetime by reducing sulfur poisoning, thus lowering operating costs and maintenance frequency.
• Enhances methane yield and selectivity by minimizing catalyst deactivation during gasification.
• Enables efficient processing of wet biomass and wastes with high and variable sulfur content.
• More reliable and continuous operation of gasification plants due to efficient and robust sulfur removal.
• Facilitates the use of novel trap materials, such as carbon-metal hybrids, which are more stable under harsh supercritical water conditions.

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Patent Abstract

It is the objective of the present invention to provide a process for the catalytic supercritical water gasification of wet biomass and/or wastes wherein the process show a high efficiency and a long durability of the catalytic components used in the gasification reaction due to a low or negligible sulfur content in the process stream entering the gasification reactor.This objective is achieved according to the present invention by a process for the catalytic supercritical water gasification of wet biomass and/or wastes, comprising the steps of:a) pressurizing and heating a pumpable water-based slurry of the biomass and/or wastes and optionally other additives to supercritical water conditions, T> 374°C, P>22.1 MPa, and removing phase separated salts and/or solid particles via a brine extraction line in order to produce a desalinated process stream;b) bringing the desalinated process stream under supercritical water conditions, T> 374°C, P>22.1 MPa, into contact with a first sulfur trap; said first sulfur trap being equipped with a first trap material comprising metal oxide based material in order to reduce the sulfide content of the desalinated process stream;c) bringing the desalinated process stream under supercritical water conditions, T> 374°C, P>22.1 MPa, into contact with a second sulfur trap; said second sulfur trap being equipped with a second trap material comprising material based on metal chalcogenide (MXy, X=O,S,Se,Te) and/or on hybrid carbon metal chalcogenide (MXy:C, X= O, S, Se, Te) and/or on hybrid metal-carbon materials (M:C) in order to reduce the concentration of the organosulfur compounds of the desalinated process stream; wherein step c) either follows step b) or is executed prior to step b);d) bringing the desalinated and desulphurized process stream into a hydrothermal gasification catalytic reactor in order to generate a methane-containing process stream;e) cooling the methane-containing process gas stream to a temperature above the temperature for methane hydrate formation; andf) depressurizing the cooled methane-containing process gas stream and separating the gaseous phase from the liquid phase.