Figure 2. The rise in higher-energy density. atmosphere. Biochar is one of the most promising agricultural breakthroughs since the discovery of fertilizers. Producing biocarbon is achieved through the process known as slow py-rolysis. Heating the material very quickly, or fast pyrolysis, produces bio-oil, with biocarbon as a byproduct. GASIFICATION Gasification is a pyrolysis process that creates producer gas, a low-energy gas containing mainly carbon monoxide and hydrogen (methane may also be pres-ent, especially at lower gasification tem-peratures). A pioneer in biomass gasifi-cation was Philippe Lebon (or Le Bon) D’Humbersin (1767-1804). In 1801, he put on a light demonstration in Paris that was fuelled by the gasification of wood. Unfortunately, the young entrepreneur was murdered three years later, before he could develop the technology further. Biomass gasification technologies can be divided into three categories: fixed-bed, fluidized-bed and entrained-flow. Fixed-bed gasifiers use a simple grate system whereby the process begins with a combustion zone that produces carbon dioxide and water; these products are then passed through a reducing zone to produce carbon monoxide and hydrogen. Fixed-bed reactors are usually utilized in systems of less than 5 MW. There are two types of fixed-bed gasifiers – updraft and downdraft – each of which has its advan-tages. Updraft gasifiers are a simple design but are prone to higher release of tars and other impurities. Downdraft gasifiers, while reducing the tar content, require a drier biomass feed and lose some of the biocarbon with the ash. Fluidized-bed gasifiers are structurally more complex than fixed-bed, but generally MegaDome ® pre-engineered fabric buildings give you practical and cost effective space for any industrial or environmental application. BuildWorks delivers innovative design-build solutions. MegaDome structures are CSA-A660 certified and building code compliant. Canada & N.America Western Canada www.megadomebuildings.com 1.888.427.6647 604.794.3628 buildworks.com/megadome 24 Canadian BIOMASS NOVEMBER/DECEMBER 2012
Canadian Biomass November/December 2012: Page 24
