The gaseous hydrocarbon fuel combustion process diagnostics using laser-spark emission spectrometry

To solve the gaseous hydrocarbon fuel combustion process control and diagnostics problem, it is proposed to apply the laser-spark emission spectrometry methods. In propane-air mixture combustion, three modes are investigated: stoichiometric combustion, an enriched mixture, and a lean mixture. A laboratory stand has been developed to study combustion processes by laser-spark emission spectrometry. The plasma radiation spectral characteristics an experimental study results formed in a flame when exposed to laser radiation are presented.

Characterization of Organic Matter from Bituminous Coals of Lafia-Obi, Middle Benue Trough, Nigeria

The present work deals with a study based on the geochemical techniques such as biomarkers, Rock-Eval pyrolysis, and detailed petrographic study to evaluate hydrocarbon generation potential of coal by collecting nine coal and carbonaceous shale samples from boreholes in Awgu Formation of Middle Benue Trough, Nigeria. The values vitrinite reflectance (0.94–1.15%VR) and Tmax (446–469°C) confirmed that samples are matured enough to generate liquid and gaseous hydrocarbon in coal. The coal samples also contain sufficient quantity of vitrinite and liptinite macerals varying from 70.28% to 74.10 wt%, which confirm the production of liquid hydrocarbon. The cross-plot between H/C and O/C atomic ratio indicates that samples were predominant in the bituminous rank and having kerogen Type III makes it suitable for hydrocarbon generation. Similar results were found in Rock-Eval pyrolysis analysis (Types II-III and Type III kerogen). The homohopane index (C35/C31 - C35) and homohopane ratio (C35αβS/C34αβS) range from 0.02 to 0.12 and 0.15 to 0.92 indicates oxic condition during organic matter deposition from Lafia-Obi samples. The Moretane/Hopane, Hopane/Hopane + Moretane, Ts/Ts + Tm, 22S/22S + 22RC32homohopane ratios range from 0.06 to 0.14; 0.88 to 0.94; 0.34 to 0.66; and 0.53 to 0.62 and 20S/20S+20R and αββ/αββ+ααα C29 ratios range from 0.43 to 0.58 and 0.42 to 0.55 indicate samples ar e within the late oil window/gas phase. Plots of 22S/22S+22R C32hopanes against C29αββ/αββ+ααα steranes show that Lafia-Obisamples are thermally mature.

SPECTRAL DIAGNOSTICS OF THE HYDROCARBON FUEL COMBUSTION PROCESS

It is proposed to use the methods of applied optical spectroscopy to solve the problem of control and diagnostics of gaseous hydrocarbon fuel combustion in this work. The results of an experimental study of spectroscopic informative parameters characterizing the propane combustion process are presented for three modes: combustion of pure propane without air supply, stoichiometric combustion and combustion with a change in the amount of supplied air relative to stoichiometric combustion. As a result of the experiment, it was found that the most intense bands in the emission spectrum of the flame arising from the combustion of propane correspond to the spectral bands of radicals of combustion products: OH, CH, and C2. While the intensities of various systems of bands in the flame spectrum depend significantly on the composition of the combustible mixture.

Waste-to-Fuels: Pyrolysis of Low-Density Polyethylene Waste in the Presence of H-ZSM-11

Herein, the pyrolysis of low-density polyethylene (LDPE) scrap in the presence of a H-ZSM-11 zeolite was conducted as an effort to valorize plastic waste to fuel-range chemicals. The LDPE-derived pyrolytic gas was composed of low-molecular-weight aliphatic hydrocarbons (e.g., methane, ethane, propane, ethylene, and propylene) and hydrogen. An increase in pyrolysis temperature led to increasing the gaseous hydrocarbon yields for the pyrolysis of LDPE. Using the H-ZSM-11 catalyst in the pyrolysis of LDPE greatly enhanced the content of propylene in the pyrolytic gas because of promoted dehydrogenation of propane formed during the pyrolysis. Apart from the light aliphatic hydrocarbons, jet fuel-, diesel-, and motor oil-range hydrocarbons were found in the pyrolytic liquid for the non-catalytic and catalytic pyrolysis. The change in pyrolysis temperature for the catalytic pyrolysis affected the hydrocarbon compositions of the pyrolytic liquid more materially than for the non-catalytic pyrolysis. This study experimentally showed that H-ZSM-11 can be effective at producing fuel-range hydrocarbons from LDPE waste through pyrolysis. The results would contribute to the development of waste valorization process via plastic upcycling.

Dimethyl Ether and Liquefied Petroleum Gas Co-Fumigation and Oxidation Catalyst Exhaust Aftertreatment: A Synergy for Improvement of Thermal Efficiency and Emissions in a Dual-Fuel Engine

Gaseous hydrocarbon (HC) fuels or alcohols can partially replace diesel in compression ignition engines through the dual-fuel mode of combustion. However, such dual-fuel mode faces the challenges of high carbon monoxide (CO) and unburnt HC emissions and low thermal efficiency, particularly at low loads. The objective of this study is to achieve dual-fuel engine thermal efficiency and emissions better than those of a diesel mode while utilizing alternative fuels. A new approach consisting of a combined strategy using dimethyl ether (DME) as a co-fumigant with liquefied petroleum gas (LPG) and deployment of a customized oxidation catalyst in a single-cylinder diesel engine is presented. DME is a high-cetane oxygenate which can be produced from renewable biomass feedstock. DME and LPG are miscible, and they can be handled and stored similarly. The diesel energy replacements (36–64%) by DME and LPG are studied at low-load to part-load conditions. A customized oxidation catalyst is benchmarked with a commercial one. The dual-fuel combustion exhibits low-temperature and high-temperature reactions with significant improvement in combustion phasing. The dual-fuel mode outperforms the diesel mode and has higher thermal efficiency. The dual-fuel mode with the customized oxidation catalyst achieves emissions of CO, HC, and smoke lower than those of the diesel mode by up to 94%, 89%, and 94%, respectively. The dual-fuel engine effectively utilizes the alternative fuels and achieves drastically reduced emissions and higher thermal efficiency as compared with the diesel mode.