Abstract: When CFG's are supplied to a gas tank 2, the fluctuation ratio of the gas calories of the CFG's is restrained by supplying the CFG's different time delays and mixing them. When the CFG's are mixed with BFG in a gas mixer 3, the gas flow rate of the BFG is controlled by feedback control based on the gas calories of a mixed gas, thereby controlling the gas calories of the mixed gas to be specific.

Abstract: A method for mechanically removing roots from harvested cormatose plant bodies using a special root removing arrangement comprises supplying the harvested cormatose plant body (3) in between two parallel spaced horizontal rollers (1,2) while they are rotating in opposite directions relative to each other so that their peripheral or opposing adjacent inner sides are moving upwards, or in the same rotational direction so that one of these peripheral surfaces on opposing adjacent inner sides is moving upwards, in order that the plant bodies roll on the rollers and become balanced and oriented substantially axially of the rollers, changing the rotational mode of the rollers into a counter rotation mode so that their peripheral surfaces on the opposing inner sides are moving downwards, drawing the beard-like roots (4) of each plant body (3) into the gap between the rollers, forcing each plant body away from the rollers by a plant body thrusting mechanism (5,6,7) to cause the roots to be plucked from the plant body