Biogas Purification System for Automotive Application

Abstract

The primary focus of this work is to investigate and compare the currently available approaches for upgrading biogas. Biogas upgrading entails the removal of CO₂, H₂S, and other potential contaminants from biogas. CO₂ removal raises the content of CH₄, giving the biogas a higher calorific value and allowing injection into the gas grid. Because of its corrosive nature, H₂S must be eliminated. Automation can be used to complete this elimination. In this case, we used PLC.

Five techniques have been investigated. Chemical absorption of H₂S into iron-chelated solutions offers highly efficient removal of H₂S from a gaseous biogas stream. The iron-chelated solutions function as a pseudo catalyst that can be regenerated. The H₂S is removed almost completely and converted to elemental sulphur. After the absorption process, a scrubber is needed to remove the CO₂. When an estimate of the costs for each technique has been made, an objective comparison will be made.

The contents of H₂S and CO₂ are removed by a chemical process and water scrubbing method which is done by a processing tank. Here we use a water scrubbing tank and a chemical process tank. This chemical process is known as glycol washing.  The washing agent used in the glycol washing process is a mixture of dimethyl ether and polyethylene glycol. The density of the washing agent varies between different formulations but is around 1 kg/l. This process removes the content of H₂S and CO₂. The whole process is controlled by PLC.