S. Dasappa

Development of producer gas engines

Abstract This paper summarizes the findings involved in the development of producer gas fuelled reciprocating engines over a time frame of six years. The high octane rating, ultra clean, and low-energy density producer gas derived from biomass has been examined. Development efforts are aimed at a fundamental level, wherein the parametric effects of the compression ratio and ignition timing on the power output are studied. These findings are subsequently applied in the adaptation of commercially available gas engines at two different power levels and make. Design of a producer gas carburettor also formed a part of this developmental activity. The successful operations with producer gas fuel have opened possibilities for adapting a commercially available gas engine for large-scale power generation application, albeit with a loss of power to an extent of 20–30 per cent. This loss in power is compensated to a much larger extent by the way toxic emissions are reduced; these technologies generate smaller amounts of toxic gases (low NOx and almost zero SOx), being zero for greenhouse gas (GHG).

Biomass gasification¿a substitute to fossil fuel for heat application

The paper addresses case studies of a low temperature and a high temperature industrial heat requirement being met using biomass gasification. The gasification system for these applications consists of an open top down draft reburn reactor lined with ceramic. Necessary cooling and cleaning systems are incorporated in the package to meet the end use requirements. The other elements included are the fuel conveyor, water treatment plant for recirculating the cooling water and adequate automation to start, shut down and control the operations of the gasifier system. Drying of marigold flower, a low temperature application is considered to replace diesel fuel in the range of

Gasifiers and combustors for biomass – technology and field studies

125-150 1\hspace{2mm} h^{-1}

The gasification of wood-char spheres in CO2---N2 mixtures: analysis and experiments

. Gas from the

Results of an Indo-Swiss programme for qualification and testing of a 300-kW IISc-Dasag gasifier

500 kg\hspace{2mm} h^{-1}

Gaseous Emissions Using Producer Gas as Fuel in Reciprocating Engines

, gasifier system is piped into the producer gas burners fixed in the combustion chamber with the downstream process similar to the diesel burner. The high temperature application is for a heat treatment furnace in the temperature range of 873–1200 K. A

Wood-char gasification: experiments and analysis on single particles and packed beds

300 kg \hspace{2mm}h^{-1}

Portable single-pan wood stoves of high efficiency for domestic use

of biomass gasifier replaces 2000 1 of diesel or LDO per day completely. The novelty of this package is the use of one gasifier to energize 16 burners in the 8 furnaces with different temperature requirements. The system operates over 140 h per week on a nearly nonstop mode and over 4000 h of operation replacing fossil fuel completely. The advantage of bioenergy package towards the economic and environmental considerations is presented.

Rural bioenergy centres based on biomass gasifiers for decentralized power generation: case study of two villages in southern India

This paper deals with biomass-based energy devices developed in recent times. The need for this renewable energy for use in developing countries is first highlighted. Classification of biomass in terms of woody and powdery (pulverized) follows, along with comparison of its energetics with fossil fuels. The technologies involved, namely gasifier-combustor, gasifier-engine-alternator combinations, for generation of heat and electricity, are discussed for both woody biomass and powdery biomass in some detail. The importance of biomass to obtain high-grade heat through the use of pulverized biomass in cyclone combustors is emphasized. The technoeconomics is discussed to indicate the viability of these devices in the current world situation. The application packages where the devices will fit in and the circumstances favourable for their seeding are brought out. It is inferred that the important limitation for the use of biomass-based technologies stems from the lack of recognition of their true potential.

Five-kilowatt wood gasifier technology: Evolution and field experience

The gasification of charcoal spheres in an atmosphere of carbon-dioxide-nitrogen mixture involving diffusion and reactions in the pores is modelled and the results are compared with experiments of Standish and Tanjung and those performed in the laboratory on wood-char spheres to determine the effects of diameter, density, gas composition and flow. The results indicate that the conversion time, t(c) approximately d1.03 for large particles (> 5 mm), departing substantially from the t(c) approximately d2 law valid for diffusion limited conditions. The computational studies indicate that the kinetic limit for the particle is below 100 mum. The conversion time varies inversely as the initial char density as expected in the model. Predictions from the model show that there is no significant change in conversion time up to 60% N2 consistent with the CO2-N2 experiments. The variation of diameter and density with time are predicted. The peculiar dependence of conversion time on flow velocity in the experiments is sought to be explained by opposing free and forced convection heat transfer and the attempt is only partly successful. The studies also indicate that the dependence on the CO concentration with low CO2 is significant, indicating the need for multistep reaction mechanism against the generally accepted single-step reaction.