NOVELTY - The engine has a cylinder (10) which is provided with a porous material (20) and a catalyst arranged between a top surface and a reciprocating piston (30). The catalyst is positioned on porous material. The catalyst is positioned on a wall of cylinder, on piston or on top surface of cylinder. The porous material is mounted on top surface, and a thermal insulator (60) is arranged between top surface and porous material. The porous material is arranged between piston and top surface, and is provided with a gas adsorber to adsorb a constituent of gas introduced into cylinder.    USE - Engine such as internal combustion engine such as wankel type engine used as chemical reactor and for manufacturing acetylene and hydrogen rich gas such as methane and ethane (all claimed).    ADVANTAGE - The cylinder is provided with a porous material and a catalyst arranged between a top surface and a reciprocating piston so that the inclusion of porous material in the dead space of engine, without the deposition of a catalyst on the surface of the porous material. Thus, the engine-based compressors are operated efficiently. By changing the formulation of the lubricant, and by keeping the formulation of the lubricant at a minimum for operating the cylinders at pressures higher than the pressure in the crankcase, the oil contamination of catalyst is prevented effectively. Since the injector/spark plug is removed and replaced with a plug with a catalyst when the compression ratio of the engine is increased, the catalyst is easily accessed for removal and replacement without the need of removing the cylinder head. The non-catalytic porous material is used to maintain a lower temperature of the gas during the compression process by decreasing the power requirement and allowing larger compression ratio for a single stage when the engine is used as a compressor so that the duration of the compression is determined by adsorption of the gasses onto the adsorber. Thus, the duration of the exhaust is adjusted to prevent desorption of the adsorbed gases during the exhaust phase of the depleted gasses while reducing the need for large compressor and the power required to drive the compressors. Hence, the size of the system is reduced while allowing for the self-sustained system.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method for producing syngas; and    (2) a method for operating engine.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of the cylinder chamber with a porous material supported by the cylinder head, and thermally insulated from the cylinder head by insulated layer.    Cylinder (10)    Porous material (20)    Reciprocating piston (30)    Piston rod (40)    Thermal insulator (60)