User talk:Ramchandraiitd

BIOGAS ENRICHMENT AND BOTTLING INTO CNG CYLINDER FOR AUTOMOTIVE APPLICATIONS: An estimate indicates that India has a vast potential of generating 6.38 x 1010 m3 of biogas from 980 million tones of cattle dung produced annually. The heat value of this gas amounts to 1.3 x 1012 MJ. In addition, 350 million tons of compost would also be produced annually.

Biogas comprises of 60-65% methane, 35-40 % carbon dioxide, 0.5-1.0 % hydrogen sulfide and traces of water vapour. It is almost 20% lighter than air and has ignition temperature of 650-750 ºC. Its calorific value is 20 M J (4713 kcal) per cubic meter. Biogas, like Liquefied Petroleum Gas (LPG) cannot be converted to liquid state under normal pressure and temperature. Critical temperature for liquefaction of methane is - 82.1 oC at 4.71 MPa pressure. In such situations, removing carbon dioxide and compressing it into cylinders makes it easily usable for transport applications, three wheelers, cars, pick up vans etc and also for stationary engines for various applications at long distances. Since CNG technology has already been into use and therefore, bio-methane (enriched biogas) which is nearly same as CNG, can be used for all applications for which CNG is being used. The enriched biogas (without CO2) has its calorific value as 34 MJ/m3 against 20 MJ/m3 of raw biogas. Enriched biogas can be successfully used as substitute of CNG in internal combustion engines.

A CO2 scrubbing and bottling technology has been designed and developed at Indian Institute of Technology Delhi based on physical absorption of carbon dioxide in water. 95-99 % CO2 can be removed by this method from biogas.

Ram Chandra Research Scholar IIT Delhi, Hauz Khas New Delhi-110016