An updraft, wood-chip gasifier was built by Applied Engineering Company in 1980 in Georgia (Jackson, 1982). At that time, the unit was the largest of its kind. It was sized at 26.4 GJ/h, fed with 2.8 t/h of wood chips, and supplied a hospital with steam. A similar unit was built in late 1981 for the Florida Power Corporation. The unit fired one of six boilers in a 30-MW power system. The gasifier was cylindrical in shape, insulated with firebrick, and enclosed in a carbon steel shell. Air was injected at the bottom, and green tree chips having a heating value of about 9.3 to 10.5 MJ/kg and 40 to 50% moisture content were charged at the top. Ash was removed from the bottom. In the design used, oxidation of the wood char occurs at the top of the grate, which is located just above the ash hoppers, and produces temperatures of about 1370°C. Pyrolysis and cracking occur in the middle of the gasifier, and incom­ing wood is dried by the exiting hot gases. Typical dry gas analyses were 26 to 30 mol % carbon monoxide, 2 to 3 mol % hydrocarbons, 10 to 12 mol % hydrogen, and 58 to 59 mol % carbon dioxide and nitrogen. The heating value of the gas was 5.9 to 6.5 MJ/m3 (n). The gasifiers were operated quite success­fully for an extended period of time. It is noteworthy that the carbon monoxide concentration was so high. This may have been caused by the use of green wood with high moisture contents and operation at relatively high temperature in the gasification zone.