Process For Converting Carbonaceous Material Into Low Tar Synthetic Gas

Abstract

A continuous multi-stage vertically sequenced gasification process for conversion of solid carbonaceous fuel material into clean (low tar) syngas. The process involves forming a pyrolysis residue bed having a uniform depth and width to pass raw syngas there through for an endothermic reaction, while controlling the reduction zone pressure drop, resident time and syngas flow space velocity during the endothermic reaction to form substantially tar free syngas, to reduce carbon content in the pyrolysis residue, and to reduce the temperature of raw syngas as compared to the temperature of the partial oxidation zone.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims benefit of U.S. Provisional Patent Application No. 62 / 401,711 filed Sep. 29, 2016, which is hereby incorporated by reference as part of the present disclosure.FIELD OF THE INVENTION[0002]The present invention pertains to the field of gasification of carbonaceous feedstock / fuel, and in particular to a process and system for conversion of carbonaceous fuel materials into clean high quality syngas substantially devoid of tars and for the production of clean ash substantially devoid of carbon content.BACKGROUND[0003]Gasification can convert carbon-containing materials to useful chemical products. These chemical products typically involve synthesis gas (syngas), which can be further combusted to produce electricity, or chemically reacted to produce oxygenates or hydrocarbons in catalytic systems.[0004]Several types of gasification and pyrolysis methods and apparatuses have been developed to achieve efficient conversion ...

AI Technical Summary

Benefits of technology

The patent describes a process for reducing carbon dioxide and other pollutants from syngas. The process involves passing the syngas through a bed of charred material, which helps to remove carbon dioxide and other pollutants. This results in a "clean syngas" that can be used for various applications such as chemical synthesis. The process also lowers the temperature of the raw syngas and reduces its carbon content.

Problems solved by technology

Many of the gasification processes known in the art have failed due to insufficient attention to low tar production or efficient tar destructions.

Existing downdraft gasifiers require very high quality wood fuels or biomass, such as ash free wood blocks or high quality wood chips, and cannot be scaled up to economically attractive scales without severely increased tar production.

Multi-stage downdraft gasifiers which comprise separate zones for fuel pyrolysis, partial oxidation, and reduction of bed gas, have also been developed, however such gasifiers known in the art also result in substantial amount of tar production, significant tar levels retained in the syngas and the ash also containing very high levels of unconverted carbon content

This gasifier is structurally complicated, and is known for its poor controllability and flexibility of performance, and lacks any reduction zone to reduce tar content in the product gases.

The devices / systems of CZ 295,171 and WO 2015 / 090251, result in considerable amount of tar in the product gases, which in turn clogs the cleaning devices used to clean the product gases.

Further the WO 2015 / 090251 has no means to effectively manage the reduction reactions and failed to produce consistent flow and quality of syngas

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