Principles and potential of the anaerobic digestion of waste-activated sludge

Anaerobic digestion of energy crops, residues, and wastes is of increasing interest in order to reduce the greenhouse gas emissions and to facilitate a sustainable development of energy supply. Production of biogas provides a versatile carrier of renewable energy, as methane can be used for replacement of fossil fuels in both heat and power generation and as a vehicle fuel. For biogas production, various process types are applied which can be classified in wet and dry fermentation systems. Most often applied are wet digester systems using vertical stirred tank digester with different stirrer types dependent on the origin of the feedstock. Biogas is mainly utilized in engine-based combined heat and power plants, whereas microgas turbines and fuel cells are expensive alternatives which need further development work for reducing the costs and increasing their reliability. Gas upgrading and utilization as renewable vehicle fuel or injection into the natural gas grid is of increasing interest because the gas can be used in a more efficient way. The digestate from anaerobic fermentation is a valuable fertilizer due to the increased availability of nitrogen and the better short-term fertilization effect. Anaerobic treatment minimizes the survival of pathogens which is important for using the digested residue as fertilizer. This paper reviews the current state and perspectives of biogas production, including the biochemical parameters and feedstocks which influence the efficiency and reliability of the microbial conversion and gas yield.

Biogas production: current state and perspectives

Progress and recent trends in biofuels

http://aoatools.aua.gr/pilotec/files/bibliography/Biofuels%20sources,%20biofuel%20policy,%20biofuel%20economy%20and%20global%20biofuel%20projections-1912165888/Biofuels%20sources,%20biofuel%20policy,%20biofuel%20economy%20and%20global%20biofuel%20projections.pdf

Biofuels sources, biofuel policy, biofuel economy and global biofuel projections

Introduction to Energy Sources Biofuels Vegetable Oils and Animal Fats Biodiesel Biodiesel from Triglycerides via Transesterification Fuel Properties of Biodiesels Current Technologies in Biodiesel Production Engine Performance Tests Global Renewable Energy and Biofuel Scenarios Biodiesel Economy and Biodiesel Policy

Biodiesel: A Realistic Fuel Alternative for Diesel Engines

Biogas scrubbing, compression and storage: perspective and prospectus in Indian context

The paper presents development of biogas scrubbing and bottling system for production of Bio-CNG to substitute compressed natural gas used in automobile and transport applications. Biogas can be used in automobiles after its purification (removing CO2, H2S and vapour present in it). A CO2 scrubbing and bottling technology has been designed and developed at Indian Institute of Technology Delhi based on physical absorption of CO2 in water at elevated pressure. The developed scrubbing system is able to remove CO2 from raw biogas when pressurized raw biogas was fed into the packed bed scrubbing column and pressurized water is sprayed from top in counter-current action. The enriched biogas was compressed up to 20 MPa pressure using a three stage compressor after moisture removal and filled in special high pressure steel cylinders (as used in CNG filling). The enriched biogas filled CNG cylinders were tested in a vehicle. Biogas enrichment and compression system can be recommended for large size biogas plants as there is sufficient biogas available for bottling, thus make it an economical venture of methane farming. The technology ensures sustainable development and energy security with employment generation in rural areas using cattle dung and biomass.

Biogas Purification and Bottling into CNG Cylinders: Producing Bio-CNG from Biomass for Rural Automotive Applications

The demand for petroleum products in India has been increasing at a faster rate than the increase in domestic availability, resulting in increased imports. The transport sector is the single largest consumer of petroleum products. Secondly, about 65 % of total air pollution is caused by the emissions of pollutants from the vehicles run on petroleum products. In the wake of this, there is urgent need to introduce alternate fuels as substitutes for diesel and petrol in the transport sector. Biogas, a clean and renewable fuel, has vast potential in India. It can be supplement to petroleum products, if used in compressed form in cylinders. Here a model is conceptualized for bottling of biogas from 120 m 3 /day capacity biogas plant and its use as vehicle fuel. It can save petrol worth about 0.66 million Rs. per annum and also generate employment for 12 persons.

Shyam S. Kapdi

Papers

Biogas scrubbing, compression and storage: perspective and prospectus in Indian context

Biogas Purification and Bottling into CNG Cylinders: Producing Bio-CNG from Biomass for Rural Automotive Applications

Upgrading biogas for utilization as a vehicle fuel