Ammonia as an Alternative for Fuel Internal Combustion Engines (original) (raw)
Related papers
Using ammonia as a sustainable fuel
Journal of Power Sources, 2008
In this study, ammonia is identified as a sustainable fuel for mobile and remote applications. Similar to hydrogen, ammonia is a synthetic product that can be obtained either from fossil fuels, biomass, or other renewable sources. Some advantages of ammonia with respect to hydrogen are less expensive cost per unit of stored energy, higher volumetric energy density that is comparable with that of gasoline, easier production, handling and distribution with the existent infrastructure, and better commercial viability. Here, the possible ways to use ammonia as a sustainable fuel in internal combustion engines and fuelcells are discussed and analysed based on some thermodynamic performance models through efficiency and effectiveness parameters. The refrigeration effect of ammonia, which is another advantage, is also included in the efficiency calculations. The study suggests that the most efficient system is based on fuelcells which provide simultaneously power, heating and cooling and its only exhaust consists of water and nitrogen. If the cooling effect is taken into consideration, the system's effectiveness reaches 46% implying that a medium size car ranges over 500 km with 50 l fuel at a cost below $2 per 100 km. The cooling power represents about 7.2% from the engine power, being thus a valuable side benefit of ammonia's presence on-board.
Review on Ammonia as a Potential Fuel: From Synthesis to Economics
Energy & Fuels, 2021
Ammonia, a molecule that is gaining more interest as a fueling vector, has been considered as a candidate to power transport, produce energy, and support heating applications for decades. However, the particular characteristics of the molecule always made it a chemical with low, if any, benefit once compared to conventional fossil fuels. Still, the current need to decarbonize our economy makes the search of new methods crucial to use chemicals, such as ammonia, that can be produced and employed without incurring in the emission of carbon oxides. Therefore, current efforts in this field are leading scientists, industries, and governments to seriously invest efforts in the development of holistic solutions capable of making ammonia a viable fuel for the transition toward a clean future. On that basis, this review has approached the subject gathering inputs from scientists actively working on the topic. The review starts from the importance of ammonia as an energy vector, moving through all of the steps in the production, distribution, utilization, safety, legal considerations, and economic aspects of the use of such a molecule to support the future energy mix. Fundamentals of combustion and practical cases for the recovery of energy of ammonia are also addressed, thus providing a complete view of what potentially could become a vector of crucial importance to the mitigation of carbon emissions. Different from other works, this review seeks to provide a holistic perspective of ammonia as a chemical that presents benefits and constraints for storing energy from sustainable sources. State-of-the-art knowledge provided by academics actively engaged with the topic at various fronts also enables a clear vision of the progress in each of the branches of ammonia as an energy carrier. Further, the fundamental boundaries of the use of the molecule are expanded to real technical issues for all potential technologies capable of using it for energy purposes, legal barriers that will be faced to achieve its deployment, safety and environmental considerations that impose a critical aspect for acceptance and wellbeing, and economic implications for the use of ammonia across all aspects approached for the production and implementation of this chemical as a fueling source. Herein, this work sets the principles, research, practicalities, and future views of a transition toward a future where ammonia will be a major energy player.
Carbon and Nitrogen Footprint Optimisation of Ammonia as an Automotive Fuel
Chemical Engineering Transactions, 2017
The transportation sector is one of the primary contributors to the global CO₂ emissions. Recent research suggests that ammonia is a potential alternative automotive fuel due to its favorable storage properties and the mature infrastructure for its production and distribution. However, there remains the question of whether ammonia can be a sustainable alternative automotive fuel on a life-cycle basis. The energy-intensive production process and the need for a secondary fuel are two major issues with the use of ammonia. A comparative well- to-wheel life cycle assessment of selected ammonia-based fuel cycles is done. Two conventional fossil fuel- based ammonia production processes and two proposed biomass-based processes are considered, namely: steam reforming, partial oxidation, a cyanobacterial (Anabaena) process, and a willow-based (Salix) process. The end-use is propulsion of a light-duty internal combustion engine vehicle, and the functional unit is 1 km of distance driven by a s...
Ammonia Application to Reciprocating Engines. Volume 1
1967
Performance with the spark-ignition conversion, exceeded that with diesel pilot fuel. Effect of varying the compression ratio was also investigated. Direct injection. of liquid ammonia into a high compression ratio (30: 1) engine was attempted and was unsuccessful. Various other auxiliary aids such as fuel at ditives, ionization and radio frequency dissociation were also investigated. A total of 1128 engine test hours were accumulated on the sparkignition engine of which 1045 were with ammonia fuei; 954 hours (911 with ammonia) were accumul'ated onthe compressi t-ignition engine. FOREWORD Logistics studies of Army operations, in World War II and Korea established, that apprcximately 65 percerft of the tbtal tonnage required for support of combat-operations iconsisted of fuels and lubricants. To compound this already heavy logistical, burden, future Army concepts envision increased mechanication and greater emphasis on mobility and dispersicn. Faced with these problems, the Army searched for other materials arid devices for vehicle propulsion. Nuclear energy seemed to be the apparent answer. H
Combustion Characteristics of Ammonia in a Modern Spark-Ignition Engine
SAE Technical Paper Series, 2019
Ammonia is now recognized as a very serious asset in the context of the hydrogen energy economy, thanks to its non-carbon nature, competitive energy density and very mature production, storage and transport processes. If produced from renewable sources, its use as a direct combustion fuel could participate to the flexibility in the power sector as well as help mitigating fossil fuel use in certain sectors, such as long-haul shipping. However, ammonia presents unfavorable combustion properties, requiring further investigation of its combustion characteristics in practical systems. In the present study, a modern single-cylinder spark-ignition engine is fueled with gaseous ammonia/air mixtures at various equivalence ratios and intake pressures. The results are compared with methane/air and previous ammonia/hydrogen/air measurements, where hydrogen is used as combustion promoter. In-cylinder pressure and exhaust concentrations of selected species are measured and analyzed. Results show that ammonia is a very suitable fuel for SI engine operation, since high power outputs were achieved with satisfying efficiency by taking advantage of the promoting effects of either hydrogen enrichment or increased intake pressure, or a combination of both. The performances under NH3 fueling compare well with those obtained under methane operation. High NOx and unburned NH3 exhaust concentrations were also observed under fuel-lean and fuel-rich conditions, respectively, calling for additional mitigation measures. A detailed combustion analysis show that hydrogen mainly acts as an ignition promoter. In the engine, pure ammonia combustion is assumedly mainly driven by the ignition kinetics of ammonia and the flame response to turbulence rather than by the laminar burning velocity.
Use of ammonia as a fuel for SI engine
Fourth European …, 2009
This numerical study examines the combustion characteristics of premixed ammonia-air mixtures, with equivalence ratios around stoichiometry, at elevated pressure and temperature conditions which are encountered in SI engine operations. The laminar burning velocity, the final flame temperature and species concentrations were determined using the Konnov's mechanism . A flat freely propagating flame was considered. Both equivalence and compression ratios have an important impact on the laminar burning velocity and on the adiabatic flame temperature. Furthermore, only the variation of the equivalence ratio has a major incidence on the nitrogen monoxide formation. The compression ratio and, therefore, the final temperature do not have a significant impact on NO yields for equivalence ratios above the stoichiometry.
Ammonia: It's Transformation and Effective Utilization
6th International Energy Conversion Engineering Conference (IECEC), 2008
In practical use, ammonia (NH 3) can be burned directly in internal combustion (IC), diesel or Stirling engines. However, because NH 3 has such a low flame temperature and is hard to ignite, it has generally not been widely used in these applications. Because NH 3 can be easily reformed into hydrogen (H 2), and as part of the effort to examine the benefits of ammonia for terrestrial applications, we develop processes for catalytic reformation of NH 3 and utilize microfibrous materials to encapsulate reforming catalyst. After demonstrating reformation of NH 3 studies were conducted on the stability and feasibility of burning NH 3 by itself and burning NH 3 with synthetic reformate. Favorable conditions for flame stability of combustion of hydrogen reformed from ammonia through this catalyst-impregnated microfibrous porous media were obtained and the results are presented. Initial findings demonstrated stable catalytic combustion and flame temperatures of 940ºC were obtained. Nomenclature ε = energy density f = flow rate Q b
In the present study, the effects of ammonia fumigation on the engine performance and exhaust emissions have been investigated experimentaly in a small diesel engine. Experiments have been performed for (2, 4, 6, 8, 10)% (by vol.) ammonia ratios at different engine speeds and loads. Here, 25% ammonia solution (25% ammonia + 75% water) have been used and this solution has been injected into intake air by a carburetor, which main nozzle section is adjustable. The test results showed that brake specific fuel consumption (bscf) increases at 2000 and 3000 rpms, but it decreases at 2600 rpm. The maximum reduction of bsfc has been determined as 7.28% for 5.48% ammonia ratio at 2600 rpm. Effective efficiency increases at all of the selected engine speeds and loads. However, the increase ratios of effective efficiency at 2600 rpm are higher than that of the other engine speeds. Exhaust emissions have been measured at 2200 rpm for different ammonia ratios and different loads and at 2600 rpm for different ammonia ratios, under only 6 Nm loads. It has been determined that carbon dioxide generally reduces at selected two engine speeds. However, nitrogen oxides, hydrocarbons and carbon monoxide generally increase. Total fuel cost for applied different ammonia ratios becomes lower than that of neat diesel fuel at 2600 rpm. At the other selected engine speeds; although total fuel cost decreases for some working conditions, it increases in some operating conditions. The maximum reduction of total fuel cost has been determined as 8.87% for 5.48% ammonia ratio at 2600 rpm.