TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: The heat treatment is made by mixing the raw biosyngas exiting the gasifier with the gas stream exiting a plasma torch (13). The raw biosyngas is injected into an arc discharge zone of an air stream from the plasma generator with velocity of 6-800 m/second, temperature of 3-5 degrees C, and then enters a decomposition reactor where the temperature is 1200-1300 degrees C for 2 seconds. The heat treated biosyngas is conditioned by adjusting the hydrogen:carbon monoixde (H2:CO) ratio by a water shift reaction converting CO in the syngas to CO2 and H2 by reacting CO with water, before entry into the Fischer-Tropsch synthesis. The conditioning of the heat treated biosyngas also involves removal of at least a portion of the CO2 or nitrogen (N2) in the biosyngas. The gasifier is fed with biomass containing cellulose. Preferred Components: The poisonous compounds are at least one of compound containing alkaline earth metals, sulfur, halogens, and nitrogen.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Device: The gasifier is a counter counter-current-flow shaft gasifier comprising a waste/biomass inlet with a two-port sluice system for introduction of waste/biomass in the upper region of the gasifier; a carbonization zone; a partial oxidation and vitrification zone; inlet (3) for injection of preheated air at the partial oxidation and vitrification zone; a slag and metal alloy accumulating section (7); unit (8) for tapping and collecting liquid slag and metal alloy; and device for regulating the injection of fresh air to maintain a temperature of 1.450-1.55 degrees C in the slag and metal alloy accumulating section. The decomposition reactor (15) comprises a plasma torch placed in a T-junction on the outlet tube (9) providing an arc discharge zone in which air is injected, and that the heated air exits the plasma torch through zone, where it is mixed with raw biosyngas, and that the mixed gas then flows into a decomposition chamber. The plasma torch is formed as a cylindrical tube closed in one end and open in the other end and which is equipped with a set of apertures for injection of air. In the device, an electric arc is formed between two annularly shaped electrodes and which is rotated and controlled by annularly shaped magnets. The opening of the cylindrical tube is directed into tube and thus forming a zone, where air heated by passing through apertures and into arc can pass into tube. The pipe is equipped with unit for regulating the injection of air (11) such that the oxidation degree in the zone and decomposition reactor is kept so that a ratio of carbon dioxide (CO2) to sum of carbon monoxide and CO2 is 0.2-0.4. EXAMPLE - No suitable example given.