This process was developed by Manufacturing and Technology Conversion International, Inc. (Durai-Swamy, Colamino, and Mansour, 1989; Durai — Swamy et a I., 1990). Biomass is reacted with steam in an indirectly heated fluid-bed gasifier at a temperature of 590 to 730°C. This process uses pulse — enhanced, gas-fired, Helmholtz pulse combustors consisting of compact, multi­ple resonance tubes which serve as the in-bed heat transfer surface. The pulsed heater generates an oscillating flow in the heat transfer tubes that results in turbulent mixing and enhanced heat transfer. Higher heat transfer coefficients than those available in conventional fire-tube configurations were estimated for this process. A medium-energy gas is produced at steam-to-biomass ratios of about 1.0. Based on carbon, the dry gas, char, and tar and oil yields were typically 90%, 4 to 8%, and 1 to 3%, respectively. Dry gas compositions from a wide variety of biomass (wood chips at 20 wt % moisture, pistachio shells and rice hulls at 9 wt % moisture, and recycled waste paper with plastic) ranged from 19 to 24 mol % carbon monoxide, 20 to 28 mol % carbon dioxide, 8 to 12 mol % methane, and 35 to 50 mol % hydrogen. The C2-C5 hydrocarbons ranged from a low of about 0.5 mol % to a high of about 6 mol % depending on the feedstock. The higher heating values of the product gas ranged from 12.9 to 15.9 MJ/m3 (n). This work was conducted in a reactor shell 2.9 m in height; the overall height was 4.6 m including the plenums. The biomass feed rates were about 9 to 13.6 kg/h. Pilot tests in different scales of reactors from 0.2 to 68 t/day with different feedstocks have been carried out. A 15-t/day demonstration unit has been constructed and operated on waste cardboard feedstocks in California, and after relocation to Maryland, the plant was oper­ated on wood chips, straw, and coal (Mansour, Durai-Swamy, and Voelker, 1995). A 109-t/day plant for processing black liquor has been built in North Carolina, and a similar plant has been built in India for processing spent distillery waste. Several cogeneration plants ranging in size from 5 to 50 MW are envisaged for more than 500 sugar mills in India.