Researches on Hydrogen
1975: On Board Hydrogen Generator for a partial Hydrogen Injection Internal Combustion Engine
Research in 1975 examined hydrogen enhanced gasoline in lean combustion. John Houseman and D.J Cerini of the Jet Propulsion Laboratory produced a report for the Society of Automotive Engineers titled “On-Board Hydrogen Generator for a Partial Hydrogen Injection Internal Combustion Engine”, and F.W. Hoehn and M.W. Dowy, also of the Jet Propulsion Lab, prepared a report for the 9th Intersociety Energy Conversion Engineering Conference, titled “Feasibility Demonstration of a Road Vehicle Fueled with Hydrogen Enriched Gasoline.
1977: Emissions and Total Energy Consumption of a Multicylinder piston engine running on Gasoline and a Hydrogen-Gasoline Mixture
Conducted research using hydrogen as a supplemental fuel to gasoline on a 1969 production engine. Their research specifically demonstrated that the higher flame speed of hydrogen was responsible for being able to extend the efficient lean operating range of a gasoline engine. They successfully used a methanol steam reformer for in situ production of carbon monoxide and hydrogen. Lean-mixture-ratio combustion in internal-combustion engines has the potential of producing low emissions and higher thermal efficiency for several reasons. First, excess oxygen in the charge further oxidizes unburned hydrocarbons and carbon monoxide. Second, excess oxygen lowers the peak combustion temperatures, which inhibits the formation of oxides of nitrogen. Third, the lower combustion temperatures increase the mixture specific heat ratio by decreasing the net dissociation losses. Fourth, as the specific heat ratio increases, the cycle thermal efficiency also increases, which gives the potential for better fuel economy.
2002: Hydrogen Addition For Improved Lean Burn Capability of Slow and Fast Burning Natural Gas Combustion Chambers
Research done in 2002 shows that the “addition of hydrogen to natural gas increases the burn rate and extends the lean burn-limit”. Also concluded was that “hydrogen addition lowers HC emissions”, and with properly “retarded ignition timing” also reduces NOx emissions.
Further research in 2002 achieved results showing “a reduction of NOx and CO2 emissions”, by modeling an on-board hydrogen reformer and “varying the efficiency”. The research was specifically a “numerical investigation” done to “foresee performances, exhaust emissions, and fuel consumption of a small, multi valve, spark ignition engine fueled by hydrogen enriched gasoline”.
2003 Alabama University of Birmingham
In 2003 Tsolakis at Alabama University of Birmingham showed that “partial replacement of the hydrocarbon fuel by hydrogen combined with EGR resulted in simultaneous reductions of smoke and nitrogen oxides emissions (NOx) without significant changes to engine efficiency”. Similar results have been presented by a team of scientists from Zhejiang University, China, which found that “a little amount of hydrogen supplemented to the gasoline-air mixture can extend the flammability of the mixture… improving the economy and emissions of engines”.
2006: Application of Hydrogen Assisted Lean Operation to Natural Gas-Fueled Reciprocating Engines (HALO)
Two key challenges facing Natural Gas Engines used for cogeneration purposes are spark plug life and high NOx emissions. Using Hydrogen Assisted Lean Operation (HALO), these two keys issues are simultaneously addressed. HALO operation, as demonstrated in this project, allows stable engine operation to be achieved at ultra-lean (relative air/fuel ratios of 2) conditions, which virtually eliminates NOx production. NOx values of 10 ppm (0.07 g/bhp-hr NO) for 8% (LHV H2/LHV CH4) supplementation at an exhaust O2 level of 10% were demonstrated, which is a 98% NOx emissions reduction compared to the leanest unsupplemented operating condition. Spark ignition energy reduction (which will increase ignition system life) was carried out at an oxygen level of 9 %, leading to a NOx emission level of 28 ppm (0.13 g/bhp-hr NO). The spark ignition energy reduction testing found that spark energy could be reduced 22% (from 151 mJ supplied to the coil) with 13% (LHV H2/LHV CH4) hydrogen supplementation, and even further reduced 27% with 17% hydrogen supplementation, with no reportable effect on NOx emissions for these conditions and with stable engine torque output. Another important result is that the combustion duration was shown to be only a function of hydrogen supplementation, not a function of ignition energy (until the ignitability limit was reached). The next logical step leading from these promising results is to see how much the spark energy reduction translates into increase in spark plug life, which may be accomplished by durability testing.
2008: Effect of H2/O2 addition in increasing the thermal efﬁciency of a diesel engine
Sustainable Energy Centre, School of Advanced Manufacturing and Mechanical Engineering, University of South Australia, Mawson Lakes, SA 5095, Australia.
Using Hydrogen as an additive to enhance the conventional diesel engine performance has been investigated by several researchers and the outcomes are very promising. However, the problems associated with the production and storage of pure hydrogen currently limits the application of pure hydrogen in diesel engine operation. On-board hydrogen-oxygen generator, which produces H2/O2 mixture through electrolysis of water, has signiﬁcant potential to overcome these problems. This paper focuses on evaluating the performance enhancement of a conventional diesel engine through the addition of H2/O2 mixture, generated through water electrolysis. The experimental works were carried out under constant speed with varying load and amount of H2/O2 mixture. Results show that by using 4.84%, 6.06%, and 6.12% total diesel equivalent of H2/O2 mixture the brake thermal efﬁciency increased from 32.0% to 34.6%, 32.9% to 35.8% and 34.7% to 36.3% at 19 kW, 22 kW and 28 kW, respectively. These resulted in 15.07%, 15.16% and 14.96% fuel savings. The emissions of HC, CO2 and CO decreased, whereas the NOx emission increased.
Hydrogen Generation from Electrolysis – Final Technical Report
This report is a summary of the work performed by Teledyne Energy Systems to understand high pressure electrolysis mechanisms, investigate and address safety concerns related to high pressure electrolysis, develop methods to test components and systems of a high pressure electrolyzer, and produce design specifications for a low cost high pressure electrolysis system using lessons learned throughout the project. Included in this report are data on separator materials, electrode materials, structural cell design, and dissolved gas tests. Also included are the results of trade studies for active area, component design analysis, high pressure hydrogen/oxygen reactions, and control systems design. Several key pieces of a high pressure electrolysis system were investigated in this project and the results will be useful in further attempts at high pressure and/or low cost hydrogen generator projects. An important portion of the testing and research performed in this study are the safety issues that are present in a high pressure electrolyzer system and that they can not easily be simplified to a level where units can be manufactured at the cost goals specified, or operated by other than trained personnel in a well safeguarded environment. The two key objectives of the program were to develop a system to supply hydrogen at a rate of at least 10,000 scf/day at a pressure of 5000psi, and to meet cost goals of $600/ kW in production quantities of 10,000/year. On these two points TESI was not successful. The project was halted due to concerns over safety of high pressure gas electrolysis and the associated costs of a system which reduced the safety concerns.
Cleaning the Air and Improving Health With Hydrogen Fuel Cell Vehicles
Converting all U.S. onroad vehicles to hydrogen fuel-cell vehicles (HFCV) may
benefit air quality, health, and climate significantly, regardless of whether hydrogen is produced by steam-reforming of natural gas, wind-electrolysis, or even coal gasification. Most benefits result from eliminating current vehicle exhaust. Wind- and natural-gas-HFCV may improve health more than coal-HFCV or fossil- electric hybrid vehicles and save 3700-6400 U.S. lives annually. Wind-HFCV may benefit climate most. HFCV will hardly affect water vapor. Coal-HFCV may improve health but damage climate relative to hybrids. The near-term direct plus externality cost of hydrogen from wind-electrolysis may be below that of U.S. gasoline.
Future use of decarbonised hydrogen in industrial applications
Probably the ‘lowest hanging fruit’ for large-scale use of hydrogen in decarbonisation is by converting
existing industrial uses to lower carbon sources of hydrogen. Since hydrogen is already used in these industries, there would be few, if any, technical barriers, and decarbonisation would merely require switching to a low- or zero-carbon method of hydrogen production. As will be discussed further, production of low- or zero-carbon hydrogen will, with current technology, be higher cost than
current high-carbon hydrogen, so the main challenges to conversion will be economic and regulatory, requiring clear policy-driven actions.