Fluidized Bed Gasifiers
UGAS Gasifier Schematic

U-GAS Gasifier Schematic (Source: Gas Technology Institute)

U-GAS® Gasifier 

U-GAS® gasification technology, a single stage fluidized bed gasifier developed by the Gas Technology Institute (GTI), was designed to process all ranks of coal and provide a synthesis gas (syngas) of low-to-medium heating value. The fuel flexibility of the gasifier allows for gasifying less expensive fuels, including all ranks of coal, petroleum coke, biomass, and industrial wastes, fed either individually or in combination. Gasifier fuel flexibility allows industry to adapt to the rise and fall of fuel costs, in order to maintain a cost effective operation.

Operation
In a U-GAS® based gasification facility, a lock hopper system supplies dry fuel into the gasifier, where the fuel is reacted with steam and air or oxygen at temperatures from 840°C to 1,100°C (1,550°F to 2,000°F). The gasifier's operating pressure depends largely on the syngas' end use, ranging anywhere from 3 to 30 bar (40 to 435 psia). After appropriate gas cleaning, the syngas can be used for heating applications, generating power, or making chemicals or fuels.

When the operating temperature of the gasifier is high enough to begin melting the fuel ash (mineral content), the concentration of ash particles within the gasifier increases until a point where the ash particles cluster together, thus forming larger particles which are selectively removed from the bed. Ash is removed from the fluidized bed by gravity (when the particle's weight becomes greater than the upward force of the fluidizing gas), and falls into a lock hopper system for depressurization and subsequent disposal. This gasifier design ensures that the larger (more dense) ash particles exiting the gasifier contain minimal amounts of carbon (less than 5%), and that 95% or more of the fuel's carbon is gasified. The introduction of the reactant gases (steam and air or oxygen) are introduced at the bottom of the gasifier, through a distribution grid, and at the ash discharge port in the center of the distribution grid.

Hai Hua.jpg
Hai Hua syngas production plant in Zaozhuang City, China (Source: Gas Technology Institute)

Commercial Deployment Projects
Synthesis Energy Systems, Inc. (SES) has worldwide exclusive license for GTI's gasification technology used for both coal applications, as well as coal/biomass co-gasification (blend with less than 40% biomass) applications. SES has two projects utilizing GTI's U-GAS® gasification technology to process coal:

Hai Hua – A joint venture between SES and Shangdong Hai Hua Coal and Chemical Company Ltd. (Hai Hua) established in October 2006. Hai Hua is a $25 million syngas production plant located in Zaozhuang City, Shandong Province in China. Designed to output 28,000 standard cubic meters per hour of gross syngas, the plant is currently in commercial operation after its construction concluded in 2007.

YIMA – A joint venture between SES and Yima Coal Industry Group Co., Ltd. (YIMA) established in April 2009. YIMA is a $250 million integrated coal-to-methanol plant located in Henan Province in China. Construction was finished mid-2012 and first production of methanol occurred towards the end of 2012. The plant will ramp up to full capacity by mid-2013, converting 2400 metric tons per day (mtpd) of sub-bituminous coal into 300,000 mtpa of methanol.1

References/Further Reading

Gasifier

 
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