Figure 5.1 is a flowsheet of the process (1, 2), Feedstocks tested include wood chips, olive husks, straw and vine trimmings. The feed was screened, rechipped and dried in a rotary drier before entering the fluid bed reactor. The drying fuel was propane, but the product fuel gas would be used in a commercial venture. Air was added to the reactor to give a partial gasification reaction to provide reaction heat. This results in a poor quality, low heating value fuel gas. The reaction temperature and pressure are about 500°C and 1 atm respectively. The char formed is separated from the vapour stream in a hot gas cyclone. The char is cooled in a sequence of water cooled screw conveyors and stored in a silo. The reactor was not well defined — it was specified as a fluid bed, but seemed to behave more like a stirred bed. As the primary objective was the production of oil for testing, little instrumentation was available.

The vapour and gas streams passed through a quench vessel where they were cooled and condensed by direct contact with recycle product water. The mixture of oil and water was separated in a settlement tank before sending the oil to storage and recycling the water through an air cooler. Excess water was removed to
maintain a constant height interface in the settlement tank. The resulting water condensate had a very high COD at around 150000 and would require treatment. Further liquid was removed from the product gas in a cyclone and filter, before burning the gas in a flare. The gas from the drier was also sent to the flare to eliminate pollutants. The gas could be used internally as a fuel source for drying the feed or other process heat applications. A typical mass balance and energy output is shown in Table 5.2.