scholarly journals Quantifying the carbon conversion efficiency and emission indices of a lab-scale natural gas flare with internal coflows of air or steam

2019 ◽  
Vol 103 ◽  
pp. 133-142 ◽  
Author(s):  
Abbas Ahsan ◽  
Hamza Ahsan ◽  
Jason S. Olfert ◽  
Larry W. Kostiuk
Keyword(s):  
Natural Gas ◽  
Conversion Efficiency ◽  
Carbon Conversion

Natural Gas Decarbonization to Reduce CO2 Emission From Combined Cycles—Part II: Steam-Methane Reforming

2000 ◽  
Vol 124 (1) ◽  
pp. 89-95 ◽  
Author(s):  
G. Lozza ◽  
P. Chiesa
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Partial Oxidation ◽  
Power Plants ◽  
Combined Cycle ◽  
Performance Estimation ◽  
Thermodynamic Efficiency ◽  
Methane Reforming ◽  
Operating Pressure ◽  
Carbon Conversion

This paper discusses novel schemes of combined cycle, where natural gas is chemically treated to remove carbon, rather than being directly used as fuel. Carbon conversion to CO2 is achieved before gas turbine combustion. The first part of the paper discussed plant configurations based on natural gas partial oxidation to produce carbon monoxide, converted to carbon dioxide by shift reaction and therefore separated from the fuel gas. The second part will address methane reforming as a starting reaction to achieve the same goal. Plant configuration and performance differs from the previous case because reforming is endothermic and requires high temperature heat and low operating pressure to obtain an elevated carbon conversion. The performance estimation shows that the reformer configuration has a lower efficiency and power output than the systems addressed in Part I. To improve the results, a reheat gas turbine can be used, with different characteristics from commercial machines. The thermodynamic efficiency of the systems of the two papers is compared by an exergetic analysis. The economic performance of natural gas fired power plants including CO2 sequestration is therefore addressed, finding a superiority of the partial oxidation system with chemical absorption. The additional cost of the kWh, due to the ability of CO2 capturing, can be estimated at about 13–14 mill$/kWh.

An experimental study on the carbon conversion efficiency and emission indices of air and steam co-flow diffusion jet flames

Fuel ◽  
2021 ◽  
Vol 287 ◽  
pp. 119534
Author(s):  
M. Zamani ◽  
E. Abbasi-Atibeh ◽  
S. Mobaseri ◽  
H. Ahsan ◽  
A. Ahsan ◽  
...  
Keyword(s):  
Experimental Study ◽  
Conversion Efficiency ◽  
Carbon Conversion ◽  
Jet Flames

scholarly journals Numerical Analysis of High-Pressure Direct Injection Dual-Fuel Diesel-Liquefied Natural Gas (LNG) Engines

Processes ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 261 ◽  
Author(s):  
Alberto Boretti
Keyword(s):  
High Pressure ◽  
Steady State ◽  
Liquid Phase ◽  
Natural Gas ◽  
Power Density ◽  
Conversion Efficiency ◽  
Liquefied Natural Gas ◽  
Dual Fuel ◽  
Fuel Conversion ◽  
Better Than

Dual fuel engines using diesel and fuels that are gaseous at normal conditions are receiving increasing attention. They permit to achieve the same (or better) than diesel power density and efficiency, steady-state, and substantially similar transient performances. They also permit to deliver better than diesel engine-out emissions for CO2, as well as particulate matter, unburned hydrocarbons, and nitrous oxides. The adoption of injection in the liquid phase permits to further improve the power density as well as the fuel conversion efficiency. Here, a model is developed to study a high-pressure, 1600 bar, liquid phase injector for liquefied natural gas (LNG) in a high compression ratio, high boost engine. The engine features two direct injectors per cylinder, one for the diesel and one for the LNG. The engine also uses mechanically assisted turbocharging (super-turbocharging) to improve the steady-state and transient performances of the engine, decoupling the power supply at the turbine from the power demand at the compressor. Results of steady-state simulations show the ability of the engine to deliver top fuel conversion efficiency, above 48%, and high efficiencies, above 40% over the most part of the engine load and speed range. The novelty of this work is the opportunity to use very high pressure (1600 bar) LNG injection in a dual fuel diesel-LNG engine. It is shown that this high pressure permits to increase the flow rate per unit area; thus, permitting smaller and lighter injectors, of faster actuation, for enhanced injector-shaping capabilities. Without fully exploring the many opportunities to shape the heat release rate curve, simulations suggest two-point improvements in fuel conversion efficiency by increasing the injection pressure.

scholarly journals Assessment on Energy Conversion Efficiency and GHG Emissions Rate for Coal, Natural Gas and Biomass Power Plant in Malaysia

2021 ◽  
Vol 87 (2) ◽  
pp. 145-153
Author(s):  
Radin Diana R. Ahmad ◽  
Tiong Sieh Kiong ◽  
Sazalina Zakaria ◽  
Ahmad Rosly Abbas ◽  
Chen Chai Phing ◽  
...  
Keyword(s):  
Power Plant ◽  
Natural Gas ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
Power Plants ◽  
Emission Rate ◽  
Energy Conversion Efficiency ◽  
Combined Cycle ◽  
Gas Power Plant ◽  
Biomass Power Plant

Three different power plants have been assessed in terms of energy conversion efficiency and GHGs emission rate. The power plants are coal power plant, natural gas power plant and biomass power plant. The assessments are made by collecting fuels consumption data and generated electricity data of each power plant. In addition to the data collection, observation on operational practices have also been carried out. The energy conversion efficiency and the GHGs emission rate for all power plants are recorded to be lower than the typical values proposed by the literature. The biomass power plant recorded the lowest energy conversion efficiency at 6.47 %. Meanwhile, the natural gas power plant utilizing the combined cycle gas turbine technology recorded the highest overall energy conversion efficiency at 48.35 % and rated to emit GHGs at 0.32 kg CO2e per kWh.

scholarly journals Effect of limestone catalyst on co-gasification of coconut fronds and wood chips

2018 ◽  
Vol 225 ◽  
pp. 06009 ◽  
Author(s):  
Muddasser Inayat ◽  
Shaharin A. Sulaiman ◽  
Tham W. Hung ◽  
Fiseha M. Guangul ◽  
Firdaus Basrawi
Keyword(s):  
Conversion Efficiency ◽  
Fossil Fuels ◽  
Biomass Energy ◽  
Wood Chips ◽  
Catalyst Loading ◽  
Carbon Conversion ◽  
Heating Value ◽  
Air Passage ◽  
Tar Reforming ◽  
By Products

Biomass energy via gasification is an attractive substitute of fossil fuels. The distribution of biomass on the earth is scattered, so transportation and collection of biomass complicates the supply of biomass especially when the gasification rely on one type of biomass. Therefore, cogasification of different biomass is proposed as a potential solution for interruption-free gasification. Beside, unwanted by-products such as tar that cause blockage in downstream equipment can be minimized through the use of catalyst in gasification to accelerate tar reforming process. In this study, catalytic co-gasification of blended feedstock of 70% wood chips and 30% coconut fronds was carried out in a downdraft gasifier using limestone as primary catalyst. The effects of catalyst loading (0%, 30%, 50%, and 70% w/w) on syngas composition, gas yield, carbon conversion efficiency and heating value of syngas were investigated. The results showed that at 50% biomass to catalyst ratio, maximum H2 content of 11.39%, CO of 17.88%, carbon conversion efficiency of 69.49%, gas yield of 1.68 Nm3/kg and higher heating value of syngas 5.11 MJ/Nm3 were achieved. Higher catalyst loading (70%) blocked the air passage, which caused poor gasification. No more than 50% catalyst suggested for stable co-gasification operation.

Carbon conversion efficiency and central metabolic fluxes in developing sunflower (Helianthus annuus L.) embryos

2007 ◽  
Vol 52 (2) ◽  
pp. 296-308 ◽  
Author(s):  
Ana P. Alonso ◽  
Fernando D. Goffman ◽  
John B. Ohlrogge ◽  
Yair Shachar-Hill
Keyword(s):  
Helianthus Annuus ◽  
Conversion Efficiency ◽  
Carbon Conversion ◽  
Helianthus Annuus L ◽  
Metabolic Fluxes

Improving the Efficiency of the Advanced Injection Low Pilot Ignited Natural Gas Engine Using Organic Rankine Cycles

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
K. K. Srinivasan ◽  
P. J. Mago ◽  
G. J. Zdaniuk ◽  
L. M. Chamra ◽  
K. C Midkiff
Keyword(s):  
Natural Gas ◽  
Conversion Efficiency ◽  
Waste Heat ◽  
Injection Timing ◽  
Base Line ◽  
Nox Emissions ◽  
Oxides Of Nitrogen ◽  
Fuel Conversion ◽  
Lean Combustion ◽  
Organic Rankine Cycles

Intense energy security debates amidst the ever increasing demand for energy in the US have provided sufficient impetus to investigate alternative and sustainable energy sources to the current fossil fuel economy. This paper presents the advanced (injection) low pilot ignition natural gas (ALPING) engine as a viable, efficient, and low emission alternative to conventional diesel engines, and discusses further efficiency improvements to the base ALPING engine using organic rankine cycles (ORC) as bottoming cycles. The ALPING engine uses advance injection (50–60deg BTDC) of very small diesel pilots in the compression stroke to compression ignite a premixed natural gas-air mixture. It is believed that the advanced injection of the higher cetane diesel fuel leads to longer in-cylinder residence times for the diesel droplets, thereby resulting in distributed ignition at multiple spatial locations, followed by lean combustion of the higher octane natural gas fuel via localized flame propagation. The multiple ignition centers result in faster combustion rates and higher fuel conversion efficiencies. The lean combustion of natural gas leads to reduction in local temperatures that result in reduced oxides of nitrogen (NOx) emissions, since NOx emissions scale with local temperatures. In addition, the lean premixed combustion of natural gas is expected to produce very little particulate matter emissions (not measured). Representative base line ALPING (60deg BTDC pilot injection timing) (without the ORC) half load (1700rpm, 21kW) operation efficiencies reported in this study are about 35% while the corresponding NOx emission is about 0.02g∕kWh, which is much lower than EPA 2007 Tier 4 Bin 5 heavy-duty diesel engine statutes of 0.2g∕kWh. Furthermore, the possibility of improving fuel conversion efficiency at half load operation with ORCs using “dry fluids” is discussed. Dry organic fluids, due to their lower critical points, make excellent choices for waste heat recovery Rankine cycles. Moreover, previous studies indicate that dry fluids are more preferable compared to wet fluids because the need to superheat the fluid to extract work from the turbine is eliminated. The calculations show that ORC—turbocompounding results in fuel conversion efficiency improvements of the order of 10% while maintaining the essential low NOx characteristics of ALPING combustion.

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