Manufacture of combustible gas

摘要

A cyclic process for the manufacture of com bustible gas comprises passing hot gas from a gas-making phase through sealing means 14 which allows the hot gas to pass in one direction to a carbon monoxide conversion plant 17, 18 but which does not allow flow of the hot gas in the reverse direction or flow of waste gases from a plant-heating phase in either direction, the gas from the gas-making phases not being subject to substantial partial cooling in passing through the sealing means. The sealing means may comprise an automatically controlled mechanical valve of the hot-gas type, or an hydraulic sealing device. The conversion to carbon dioxide of the carbon monoxide in the gas from the gas-making phases may be affected by using an iron oxide catalyst only, or non-ferrous hydrogenating catalyst only, or both types of catalyst. After preliminary heating of the gas-making plant by continuous passage of heating gases from the combustion chamber 1, through the catalyst chamber 6, and waste heat boiler 12, and preliminary heating of the conversion catalyst chamber 17 by passage of superheated steam, a cyclic operation comprising a heating-phase and steam purge, followed by a gas-making phase and a second steam purge, is commenced. During the plant-heating phase air and heating fuel, e.g. petroleum gases, or petroleum distillate, are burnt in combustion chamber 1. During this phase and the subsequent steam purge the stack valve 13 is open, and, because the gas pressure is insufficient to break the hydraulic seal in 14, the gases pass through outlet 10 to the steam boiler 12 and thence to stack valve 13. After a steam purge, the stack valve 13 is closed and liquefied petroleum gas feedstock and steam are introduced through the inlets 8 and 9, and are cracked in passing through the catalyst bed 7 to form a gas comprising carbon dioxide, carbon monoxide, and hydrogen. Specifications 973,152 and 1,008,205 are referred to.