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United States Department of Agriculture

Agricultural Research Service

Title: Method and apparatus to convert a biomass reactant into synthesis gas
See also: US Patent Office Full Record


Patent Number: 7875090
Docket Number: 609
Serial Number: 12108747
Date Patented: 01/25/2011


Summary:   Disclosed are a method and a corresponding apparatus for converting a biomass reactant into synthesis gas. The method includes the steps of (1) heating biomass in a first molten liquid bath at a first temperature, wherein the first temperature is at least about C., but less than the decomposition temperature of the biomass, wherein gas comprising water is evaporated and air is pressed from the biomass, thereby yielding dried biomass with minimal air content. (2) Recapturing the moisture evaporated from the biomass in step 1 for use in the process gas. (3) Heating the dried biomass in a second molten liquid bath at a second temperature, wherein the second temperature is sufficiently high to cause flash pyrolysis of the dried biomass, thereby yielding product gases, tar, and char. (4) Inserting recaptured steam into the process gas, which may optionally include external natural gas or hydrogen gas or recycled syngas for mixing and reforming with tar and non-condensable gases. (5) Further reacting the product gases, tar, and char with the process gas within a third molten liquid bath at a third temperature which is equal to or greater than the second temperature within the second molten liquid bath, thereby yielding high quality and relatively clean synthesis gas after a relatively long residence time needed for char gasification. A portion of the synthesis gas so formed is combusted to heat the first, second, and third molten liquid baths, unless external natural or hydrogen gas is available for this use.

Patent Status: Patent application filed on April 24, 2008. Link at USPTO filed under patent title “Method and apparatus to protect synthesis gas via flash pyrolysis and gasification in a molten liquid.”


Mark A. Dietenberger
One Gifford Pinchot Dr.
US Forest Service
Madison, WI 53726
Phone: (608) 231-9531

Mark H. Anderson
University of Wisconsin Madison
Madison, WI


Last Modified: 10/1/2015
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