Operating strategy for exhaust gas reduction and performance improvement in a heavy-duty hydrogen-natural gas blend engine

Energy ◽  
2013 ◽  
Vol 50 ◽  
pp. 262-269 ◽  
Author(s):  
Cheolwoong Park ◽  
Changgi Kim ◽  
Young Choi ◽  
Janghee Lee
2021 ◽  
Author(s):  
Anand Kumar Singh ◽  
Aysha Alobeidli ◽  
Venugopal Bakthavachsalam

Abstract Natural gas coming from the well contains hydrocarbons, CO2, H2S, and water together with many other impurities. Molecular sieve treatment of the gas is required to make it suitable for the various applications. The several process and parameters considerations contribute to the reliable and optimized operation of molecular sieve natural gas treaters. The journey of this molecular sieve treater optimization commenced by conducting a thorough systematic study of all existing treater performance by considering various operating critical parameter. The technical feasibility studies were completed covering all the aspects like evaluating current performance of treater, conducting simulation for future capacity, licensor endorsement, conducting breakthrough test. Finally, study outcomes were implemented through management change process. The main benefits of optimization of molecular sieve treater process are to extend the service life of molecular sieve which enable us to increase the turnaround cycle of NGL trains. Significant reduction in CAPEX and OPEX cost were realized by reducing new fresh molecular sieve procurement, reducing disposal of molecular sieve waste material and expense of shutdown, achieving 100% HSE. This paper presents the typical operation issues and challenges in molecular sieve treatment process, best practices adopted for maximizing of existing assets considering the current and design scenarios, and performance improvement, which result to extend molecular sieve life, increase of NGL shutdown cycle and flaring reduction in trains.


2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.


Author(s):  
Mehrzad Kaiadi ◽  
Per Tunestal ◽  
Bengt Johansson

High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition Natural Gas engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. Most of the heavy duty NG engines are diesel engines which are converted for SI operation. These engine’s components are in common with the diesel-engine which put limits on higher exhaust gas temperature. The engines have lower maximum load level than the corresponding diesel engines. This is mainly due to the lower density of NG, lower compression ratio and limits on knocking and also high exhaust gas temperature. They also have lower efficiency due to mainly the lower compression ratio and the throttling losses. However performing some modifications on the engines such as redesigning the engine’s piston in a way to achieve higher compression ratio and more turbulence, modifying EGR system and optimizing the turbocharging system will result in improving the overall efficiency and the maximum load limit of the engine. This paper presents the detailed information about the engine modifications which result in improving the overall efficiency and extending the maximum load of the engine. Control-related problems associated with the higher loads are also identified and appropriate solutions are suggested.


Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes have been designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor has been highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and non-cavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.


2018 ◽  
Vol 552 ◽  
pp. 30-37 ◽  
Author(s):  
Pauliina Nevalainen ◽  
Niko M. Kinnunen ◽  
Anna Kirveslahti ◽  
Kauko Kallinen ◽  
Teuvo Maunula ◽  
...  

Author(s):  
G. P. McTaggart-Cowan ◽  
H. L. Jones ◽  
S. N. Rogak ◽  
W. K. Bushe ◽  
P. G. Hill ◽  
...  

The use of pilot-ignited, direct-injected natural gas fuelling for heavy-duty on-road applications has been shown to substantially reduce NOx and particulate matter emissions. The fuelling process involves the injection of pilot diesel near top-dead-center, followed shortly afterwards by the injection of natural gas at high pressure. The injection pressure of the gas and diesel will substantially affect the penetration of the fuel into the combustion chamber, the break-up and atomization of the diesel spray, and the mixing and nature of the turbulent gas jet. To investigate these influences, a series of experiments were performed on a single-cylinder heavy-duty engine over a range of engine operating conditions (exhaust gas recirculation fraction, engine speed, engine load). Due to the unique nature of the single-cylinder engine, it was possible to hold all other parameters constant while only varying injection pressure. The results indicated that injection pressure had a substantial impact on emissions and performance at high loads, where substantial reductions in PM and CO were observed, with only minor increases in NOx and no significant effect on tHC or fuel consumption. At low loads, no significant impact on either emissions or performance was detected. The effects of injection pressure, while still significant, were found to be reduced at increased engine speeds. Higher injection pressures were found to consistently reduce both the number density and the size of particles in the exhaust stream.


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