| 摘要 |
PURPOSE:To provide a process for producing a high-calorie city gas falling under the grade 13A in which process a gas having a pressure and a high hydrogen concentration and suitable for use as a recycle gas for hydrogeneration and desulfurization and a gas having a relatively high methane concentration disirable for a fuel gas are obtained as permeation gases. CONSTITUTION:This process comprises treating a modified gas obtained from hydrogenated and desulfurizing petroleum hydrocarbons through low-temp. steam modification and comprising methane, carbon dioxide, hydrogen, etc., with a membrane separation apparatus to obtain a mixed gas comprising methane as a major component on the upstream side of the membrane, and adding an LPG to the mixed gas to regulated caloric value, the separation apparatus being separated into a first separator and a second separator disposed in series. The downstream side of the first separator has a higher pressure than the downstream side of the second separator. The relatively hydrogen-rich gas obtained in the fist separator on its downstream side is used as a recycle gas for hydrogenation and desulfurization, while the relatively methane-rich gas obtained in the second separator on its downstream side is used as a fuel gas for the low temp. steam modification. |
