| 摘要 |
PURPOSE: To economically produce a high-calorie standard gas comparable to a natural gas by treating a gas obtained from petroleum hydrocarbons through low-temp. steam reforming with a membrane separation apparatus comprising two separators disposed in series while regulating the load sharing ratio to an optimal value. CONSTITUTION: Petroleum hydrocarbons obtained through desulfurization in a desulfurization tower are heated to 350-400 deg.C in a heating oven and then subjected to low-temp. steam reforming in a lowtemp. reforming vessel to obtain a reformed gas comprising about 75% methane, about 18% carbon dioxide, about 6% hydrogen, etc. The reformed gas is separated with a first membrane separator (a) to obtain on the upstream side of the membrane a gas which is reduced in residual carbon dioxide concentration to 4% and is used as a feedstock gas for a grade-13A gas. The gas on the downstream side of the separator (a) is compressed with a compressor and fed to and treated with a second membrane separator (b) to obtain on the upstream side of the membrane a gas which has a residual carbon dioxide concentration of 4%, the same as that for the separator (a), and a methane concentration of 95% or higher and is used as a feedstock gas for a grade-13A gas. The gases on the upstream sides of the separators (a) and (b) are mixed and introduced into an amplifier, where an LPG is added thereto for calorific value regulation to obtain a city gas having a total calorific value of 11,000kcal/Nm<3> and falling under the grade 13A. |
