Effects on CHP plant efficiency of H2 production through partial oxydation of natural gas over two group VIII metal catalysts

Abstract

1 2Blending H 2 with natural gas in spark ignition engines can increase for electric efficiency. In-situ H 2 3 production for spark ignition engines fuelled by natural gas has therefore been investigated recently, and 4 reformed exhaust gas recirculation (RGR) has been identified a potentially advantageous approach: RGR 5 uses the steam and O 2 contained in exhaust gases under lean combustion, for reforming natural gas and 6 producing H 2 , CO, and CO 2 . In this paper, an alternative approach is introduced: air gas reforming circulation 7 (AGRC). AGRC uses directly the O 2 contained in air, rendering the chemical pathway comparable to partial 8 oxidation. Formulations based on palladium and platinum have been selected as potential catalysts. With 9 AGRC, the concentrations of the constituents of the reformed gas are approximately 25% hydrogen, 10% 10 carbon monoxide, 8% unconverted hydrocarbons and 55% nitrogen. Experimental results are presented for 11 the electric efficiency and exhaust gas (CO and HC) composition of the overall system (SI engine equipped 12 with AGRC). It is demonstrated that the electric efficiency can increase for specific ratios of air to natural gas 13 over the catalyst. Although the electric efficiency gain with AGRC is modest at around 0.2%, AGRC can be 14 cost effective because of its straightforward and inexpensive implementation. Misfiring and knock were both 15 not observed in the tests reported here. Nevertheless, technical means of avoiding knock are described by 16 adjusting the main flow of natural gas and the additional flow of AGRC. 17 18

Influence of Maintenance Intervals on Performance and Emissions of a 192 kWel Biogas Gas Otto CHP Unit and Results of Lubricating Oil Quality Tests—Outcome from a Continuous Two-Year Measuring Campaign

“…However, the economic, environmental and technical performance of CHP systems, and their use in industry and buildings, has been described by various authors [4,[23][24][25][26][27]. Pourmovahed et al [27] tested the performance of 7 kW th and 1 kW el biogas CHP units in terms of thermal and electrical power output, individual and overall efficiencies, as well as exhaust gas emissions.…”

Energy characterization of CHP (combined heat and power) fuelled with hydrogen enriched natural gas blends

“…The main risk associated to hydrogen enrichment in internal combustion engine is the occurrence of knock related to local abnormal combustion. When hydrogen mixtures are used, the relative methane content decreases, and the mixtures ability to detonate improves [21].…”