For decentralized power generation in West Africa, gas from a small biomass gasification unit can be used as the main fuel in a dual-fuel engine with diesel as the pilot fuel. To study the combustion in this type of engine (Lister Petter), experiments were conducted with a surrogate gas composed of liquefied petroleum gas and nitrogen (LPGN2), the energy context of which is similar to that of syngas. The tests were conducted at different loads and for different diesel substitution rates. The combustion analysis showed that the LPGN2 mixture had an overall behaviour similar to neat diesel, while the pressure peaks were lower in dual-fuel mode. The results also indicated a longer ignition delay and a pronounced diffusive combustion phase leading to a lower indicated mean effective pressure with gas. The fuel efficiencies remained low in both mono- and dual-fuel operation. The relative instability of the combustion in dual-fuel mode gave rise to an increase in the coefficient of variation (COVIMEP). Compared to neat diesel, the engine running at low loads in dual-fuel mode showed higher emission levels of CO, a slight reduction of 2.5% of CO2 and a substantial decrease of 73% for nitrogen oxides.
16 October 2023 in Journal of Advanced Research in Fluid Mechanics and Thermal Sciences
Valorisation of local and low-cost eco-materials have become an imperative for the sustainable development of Concentrating Solar Power (CSP) in West Africa. In this study, the compatibility tests were carried out. These involve the application of jatropha curcas oil (JCCO) and ceramic balls, which were developed from clay coal bottom ash and sands with a focus on Burkina dune sand ceramic. The aim was to assess the applicability of using JCCO as heat transfer fluid in CSPs with direct thermocline thermal energy storage. The tests involve the use of a small container to put in contact with Jatropha oil with ceramic balls for 2160 hours and at 210 °C. From the chemical properties’ analysis, the peroxide value in the oil decreases with aging time while the acidity increase. However, the acidity remains below the limited value that is 25 mg KOH.g-1. Therefore, thermal properties that drive heat transfer and rheological properties (density, thermal conductivity, kinematic viscosity and so on) were not adjusted significantly at the storage temperature (of about 210°C). Thermal stability temperature decreased to 261.93°C for the oil aged alone as against 263.41 °C for the one that was put in contact with filler material. In the nutshell, there is no incompatibility between JCCO, and the new thermal energy storage material (TESM) developed. These couple of materials could be suitable for thermocline energy storage in CSP plant and for other applications like there use in solar cooker box.