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Biomass utilization through gasification could be a viable alternative energy source for meeting energy demands in decentralized manner. Thermodynamic equilibrium and other models have been proposed to explain and understand the complex biomass gasification process, design, simulation, optimization, and process analysis of gasifiers. Present paper deals with a comprehensive process model developed for biomass gasification in an atmospheric fixed bed rector using the ASPEN PLUS. The experimental facility of the gasifier developed by the authors has a provision for proper cooling and filtration system to derive satisfactory performance with low emissions. Thus the model developed using ASPEN PLUS is validated with experimental data obtained with four different types of feed stocks viz; babul wood, neem wood, mango wood, and bagasse. The model has well-predicted composition of H 2 , CO, and CO 2 whereas it has under predicted the CH 4 . The gasifier conversion efficiency was observed to be higher with babul wood when compared with other three types of wood due to its high carbon and H 2 and less ash concentrations.

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The homogeneous charge compression ignition (HCCI) combustion is considered to be the principally promising future IC engine concepts. HCCI is a concept of hybrid combustion, between the Otto engine and Diesel engine. HCCI is however not a modern finding. Already in the early twentieth century hot bulb engines operated with an HCCI-like combustion. They were superior in terms of brake efficiency compared with the contemporary gasoline engines and at the same level as the diesel engines. High engine efficiencies and ultra low NO emissions and low particulates are the benefits of HCCI engines. Volumetric auto ignited combustion of the compressed lean air-fuel mixture is attributed to these benefits. There are few drawbacks also were there in HCCI engines like, low specific output, narrow operating range, lack control over the ignition process, long start up time and high emissions like CO and UHC emissions. The CO and UHC emissions can be after treated using catalytic converters. In this study a literature review on HCCI engine has been performed and the parameters affecting the HCCI combustion phasing, performance and emissions were discussed. Strategies to widen the peak load bearing capacity of HCCI engine, reducing the emissions like NOx, CO and UHC, easy autoignition were discussed in the present study.

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The purpose of this study is to investigate the effects of water mist (WM) injected directly into an intake manifold spark ignition (SI) engine. WM flows through a nozzle at the throttle body of the four-cylinder four-stroke multi-point injection engine for testing the performance of exhaust emission system. The water is pumped in mist form into the intake manifold with an air-fuel mixture through the nozzle, which is located on the throttle body. Experimental work and simulation methods are combined by the presence and absence of WM addition, and the performance as well as emission produced by the engine is analyzed. The Gamma Technologies (GT) methods are used to simulate the model with and without WM addition. The experimental results indicate that the standard engine performance can be used to validate the simulation model. The engine measures include various parameters such as brake power, torque, volumetric efficiency, spark advance timing, and the concentration of CO and NOx with water and without water addition to the SI engine (i.e., the power, torque, volumetric efficiency of the engine is increased up to 10%). The emission of NOx is found to be significantly reduced and that of CO does not change.