Gasification

What is gasification?

Gasification is a cost efficient process that converts solid or liquid feedstock for production of transportation fuels, chemicals, heat and/or electricity. The gasification process takes place at high temperatures, exceeding 700 °C, and with a controlled amount of oxygen and/or steam.

The produced gas consists of varying levels of carbon dioxide (CO2), carbon monoxide (CO), methane (CH4), hydrogen (H2), water and lower levels of light hydrocarbons (≥C2) and tar. The gas composition depends on several different parameters such as gasification temperature, oxidant (air, oxygen, steam), reactor type and feedstock. When gasifying at higher temperatures, using oxygen, normally exceeding 1200 ° C, a product gas mainly consisting of CO and H2 is generated that can be upgraded to synthesis gas, i.e. a gas suitable for synthesis of chemical products. At gasification temperatures below 1000 ° C, a product gas with higher levels of different hydrocarbons (e.g. methane) is generated and which by means of post-gasifier catalytic or thermal cracking or by scrubbing can be further upgraded to synthesis gas. If air is used instead of oxygen in the gasifier, the product gas is diluted by nitrogen from the air and is suitable as a fuel gas for co-generation of power and heat in engines and gas turbines or used in boilers and furnaces.

“For a country like Sweden, which has substantial forest assets and a developed petrochemical industry, biomass gasification is a highly relevant technology to invest in. It is probably the cheapest and most effective “ticket” to a fossil free Sweden. This change will require long lasting political decisions on proper incentives to make it happen. Given the historic volatility of oil prices as well as political decisions we cannot hope that “ordinary market forces” will bring about this change in time. The financial and political risks are currently too high”

Måns Collin, Chairman of the SFC Program Advisory Board

A process applicable in many areas

The product gas, depending on process configuration, is well-suited for the production of methane (or synthetic natural gas (SNG) via methanation or for industrial process heat and electricity generation. The synthesis gas can be used for liquid transportation fuel or chemicals products via a number of different synthesis processes, such as:

Fischer-Tropsch synthesis, a chemical catalytic process that has been used since the 1920s to produce liquid fuels from carbon-based synthesis gas and natural gas

Methanol synthesis, a chemical catalytic process used to produce methanol

Mixed alcohol synthesis (MA), a catalytic process (oxo-synthesis) that produces a mixture of methanol, ethanol, propanol, butanol and smaller amounts of heavier alcohols

Fermentation of synthesis gas, a biological process using anaerobic microorganisms to ferment the synthesis gas for ethanol production

Conversion of carbon monoxide with water vapor (water-gas-shift, aka. WGS) for hydrogen production

Hydroformylation of olefins like ethylene and propylene to alcohols (oxo-process)

Main purposes of gasification

The main purposes of gasification are:

To provide a more flexible use of the original feedstock e.g. in gas turbines, engines or gas fired equipment

To allow separation of fuel organic components from the inorganic ash

To allow cleaning from certain contaminants such as sulphur, chlorine etc.

To access certain chemical building blocks, for example hydrogen

Gasification technologies

SFC focuses on technologies relevant to industrial interests, namely indirect fluidized bed gasification, entrained flow gasification, direct fluidized bed gasification.

More about the technologies