Experimental study of an internal combustion engine fueled by a low-calorific value producer gas

This paper describes an experimental study of the operation of an internal combustion engine of fueled by a low-calorific value gas. The main operating parameters of low-power ICE were determined. Efficiency was also evaluated when the ICE was converted to operate on producer gas. In the experiment, it was shown that the engine reached a stable operating mode under load and data on the temperature and exhaust gases composition were obtained. According to our estimates, in the steady-state operation of the internal combustion engine with a load, the efficiency factor was about 22 %. When using the model gas, the from generator output power, was about 30-40 % of the nominal value, under variable load conditions. However, it was found that in steady-state operation, the power of the internal combustion engine was 40-55% of the nominal value.

Design and experimental tests of an Imbert type downdraft gasifier prototype and clean-up system for small-scale biomass-based power generation

This paper addresses the design, development and experimental tests of a prototype of fuel gas generation system based on biomass gasification for small-scale applications, around 5 kW. It comprises the small scale downdraft gasifier and the gas cleaning system aiming to clean-up the producer gas to be used in the upstream Internal Combustion Engine (ICE). The design of the downdraft gasifier prototype follows the methodologies that have been reported on the available literature. However, since these methodologies apply to gasifiers with larger rated powers, the adopted methodology is based on the extrapolation of the main parameters used for larger gasifiers design. For runing the ICE the producer gas requires to have a specific gas composition with an acceptable range of impurities. Therefore, a clean-up system was proposed following three stages: in first instance a hot gas clean-up using a cyclone designed to eliminate particles and compounds; then a heat exchanger was used for cooling the gas to condensate tars and water; finally a cold gas clean-up is performed by filtration using two filter steps: the first one using organic material (biomass) and the second one using a polypropylene cartridge filter. Experimental tests were performed using the developed imbert downdraft gasifier prototype, using pellets as feedstock. The preliminary results allow verifying several drawbacks that will difficult an effective integration of the developed prototype for small scale power generation applications based on ICE using low density feedstock.

Effect of the Presence of HCl on Simultaneous CO2 Capture and Contaminants Removal from Simulated Biomass Gasification Producer Gas by CaO-Fe2O3 Sorbent in Calcium Looping Cycles

This study investigated the effect of HCl in biomass gasification producer gas on the CO2 capture efficiency and contaminants removal efficiency by CaO-Fe2O3 based sorbent material in the calcium looping process. Experiments were conducted in a fixed bed reactor to capture CO2 from the producer gas with the combined contaminants of HCl at 200 ppmv, H2S at 230 ppmv, and NH3 at 2300 ppmv. The results show that with presence of HCl in the feeding gas, sorbent reactivity for CO2 capture and contaminants removal was enhanced. The maximum CO2 capture was achieved at carbonation temperatures of 680 °C, with efficiencies of 93%, 92%, and 87%, respectively, for three carbonation-calcination cycles. At this carbonation temperature, the average contaminant removal efficiencies were 92.7% for HCl, 99% for NH3, and 94.7% for H2S. The outlet contaminant concentrations during the calcination process were also examined which is useful for CO2 reuse. The pore structure change of the used sorbent material suggests that the HCl in the feeding gas contributes to high CO2 capture efficiency and contaminants removal simultaneously.

The Removal of Biomass Tar Derived Producer Gas by Means of Thermal and Catalytic Cracking Methods

Tar derived from biomass gasification system needs to be eliminated before applying biomass producer gas for avoiding equipment and its gas problems. In this study, thermal and catalytic cracking methods of biomass tar along with microwave assistance in heat transfer were experimented at various temperatures during 650-1,200 °C and residence at 0.24-0.5 s. The results present that high tar removal efficiency by approximately 90 % under thermal cracking treatment and about 98 % with catalytic cracking method. It also shows that the catalytic cracking especially modified catalyst could be lowered carbon deposition on catalyst surface.

Trade-off Study on Economy and Environmental Aspects of a Dual Fuel Diesel Engine using Diesel Additive and Producer Gas

Experiments are performed on a diesel engine working in single fuel mode using fossil diesel (FD) as well as 5% and 10% (v/v) di-ethyl ether (DEE) additives with FD as fuels as well as in dual fuel mode using the above fuels as pilot fuels along with producer gas (PG) as primary fuel. This study aims to draw comparative analyses of engine combustion, performance and emission characteristics using the above fuel combinations to establish the most suitable fuel strategy for a diesel engine. The study revealed greater control over nitric oxide (NO) and smoke opacity in dual fuel mode compared to single fuel mode operations. Addition of DEE with FD, produced lower HC and CO emissions, comparable NO emissions along with reduced smoke opacity compared to FD in both modes of operation. Further, in dual fuel mode operation, the diesel percentage energy substitution (PES) reduced with increase in DEE content in the blends. The tradeoff study involving engine performance and emissions with respect to the cost of operation revealed that the fuel strategy used in dual fuel mode operation delivered better engine performance along with reduced NO emission and smoke opacity at lower operational cost compared to all the considered fuel strategy in single fuel mode operation. Especially, FD+5% DEE+PG and FD+10% DEE+PG fuel strategies were found to be the most suitable dual fuel mode combinations in a diesel engine in terms of their superior engine performance, lower emissions along with better economy.