The present disclosure provides methods and devices for preparing the fuel gas used. A device may include a furnace body, a tower type synchronous roller extruding machine with a circular ladder groove mold that is mounted at the upper end of the furnace body. The tower type synchronous roller extruding machine is provided with a bucket, the bucket is in airtight connection with the furnace body, and a first transmission shaft is mounted in the bucket. At least two tower type synchronous rollers are mounted on the first transmission shaft, and the tower type synchronous rollers are symmetrically distributed on both sides of the first transmission shaft.