METHOD FOR PURIFYING DIGESTIVE GAS IN SYSTEM FOR UTILIZING DIGESTIVE GAS AND APPARATUS FOR PURIFYING THE SAME

摘要

PPROBLEM TO BE SOLVED: To provide a method for purifying a digestive gas by which the digestive gas can inexpensively be purified throughout the year in a system for utilizing the digestive gas and to provide an apparatus for purifying the digestive gas. PSOLUTION: The system for utilizing the digestive gas is designed to purify a part after subtracting the amount utilized as a fuel for equipment for heating at least a digester or the total amount and use the purified gas as a fuel for other uses. In the system, a method for purifying the digestive gas by a high-pressure water absorbing method comprising bringing the digestive gas into contact with absorbing water in a high-pressure atmosphere in an absorption column 404 and thereby affording a purified gas in which the methane concentration is increased is used. A transient method for draining the absorbing water discharged from the absorption column 404 is used in a period in which the supply water temperature supplied from the outside of the system for purifying the digestive gas or the circulating water temperature circulated to the absorption column 404 is low. Otherwise, in a period in which the supply water temperature or circulating water temperature is high, a changeover is made to a circulating method for cooling the supply water or circulating water and then feeding the cooled supply water or circulatig water to the absorption column 404. Furthermore, the apparatus for purifying the digestive gas is provided. PCOPYRIGHT: (C)2008,JPO&INPIT