Showing papers on "Compressed natural gas published in 2016"

Postextraction Separation, On-Board Storage, and Catalytic Conversion of Methane in Natural Gas: A Review

Abstract: In today’s perspective, natural gas has gained considerable attention, due to its low emission, indigenous availability, and improvement in the extraction technology. Upon extraction, it undergoes several purification protocols including dehydration, sweetening, and inert rejection. Although purification is a commercially established technology, several drawbacks of the current process provide an essential impetus for developing newer separation protocols, most importantly, adsorption and membrane separation. This Review summarizes the needs of natural gas separation, gives an overview of the current technology, and provides a detailed discussion of the progress in research on separation and purification of natural gas including the benefits and drawbacks of each of the processes. The transportation sector is another growing sector of natural gas utilization, and it requires an efficient and safe on-board storage system. Compressed natural gas (CNG) and liquefied natural gas (LNG) are the most common form...

Research progress in the development of natural gas as fuel for road vehicles: A bibliographic review (1991–2016)

Abstract: Among all alternative fuels, compressed natural gas (CNG) has been considered as one the best solutions for fossil fuel substitution because of its availability throughout the world, inherent clean burning, economical as a fuel and adaptability to the gasoline and diesel engines. This bibliography reviews the potential of CNG as a transportation fuel. The added bibliography at the end of this article contains 1102 references to papers, conference proceedings and theses/dissertations on the subject that were published between 1991 and 2016. These references have been retrieved from 137 scientific journals. The references are classified in the following categories: Regional Experience with CNG Vehicles; Economic Aspect of CNG Vehicles; CNG Engine's Design, Control and Performance; Combustion and Fuel Injection Characteristics of CNG Engines; CNG/ Diesel Dual Fuel Operations; Hydrogen Enriched CNG Vehicles; Environmental Aspect of CNG Vehicles; Safety Aspect of CNG Vehicles.

Natural gas as vehicle fuel in China: A review

Abstract: Natural gas vehicles offer the benefits of reducing oil use, CO2 emissions and air pollutants. Promoting the use of natural gas vehicles is considered as one of the most important strategies towards sustainable transportation. China made remarkable progress in promoting natural gas vehicles over recent years, and its 4.6 million natural gas vehicles in 2014 represented the world׳s largest natural gas vehicle fleet. In this paper, the development of natural gas vehicles in China is reviewed based on a triple-perspective (Fuel-Vehicle-Infrastructure) technical–economical framework. The review indicates that (a) pricing of vehicle-use Compressed Natural Gas (CNG) and Liquefied Natural Gas (LNG) is essential in determining natural gas vehicle development. A pricing principle similar to the fixed CNG/gasoline price ratio (0.75:1) should be applied to LNG/diesel price ratio; (b) for CNG passenger vehicles, the modified CNG vehicles, with ¥3000–5000 additional cost, is more attractive to consumers than originally manufactured CNG vehicles, with about ¥10,000 additional cost. Vehicle retrofit should be permitted by the government with the precondition that retrofit standards are strictly enforced; (c) for CNG/LNG transit buses, the deployment is strongly affected by local government׳s preference. In regions with sufficient natural gas supply, the government should prioritize the deployment of CNG/LNG transit buses rather than other technologies; (d) for LNG commercial vehicles, with ¥60,000–80,000 higher cost than their counterpart diesel vehicles, financial incentive is critical for their development. China׳s current vehicle subsidy scheme should be extended to cover LNG commercial vehicles; (e) regarding refueling infrastructures, interference with urban land-use planning and long-time administrative approval are the major barriers. Local governments should launch dedicated plans and strategies to support the further deployment of CNG/LNG refueling infrastructures.

Carbon and energy footprints of electric delivery trucks: A hybrid multi-regional input-output life cycle assessment

Abstract: Due to frequent stop-and-go operation and long idling periods when driving in congested urban areas, the electrification of commercial delivery trucks has become an interesting topic nationwide. In this study, environmental impacts of various alternative delivery trucks including battery electric, diesel, diesel-electric hybrid, and compressed natural gas trucks are analyzed. A novel life cycle assessment method, an environmentally-extended multi-region input-output analysis, is utilized to calculate energy and carbon footprints throughout the supply chain of alternative delivery trucks. The uncertainties due to fuel consumption or other key parameter variations in real life, data ranges are taken into consideration using a Monte Carlo simulation. Furthermore, variations in regional electricity mix greenhouse gas emission are also considered to present a region-specific assessment for each vehicle type. According to the analysis results, although the battery electric delivery trucks have zero tailpipe emission, electric trucks are not expected to have lower environmental impacts compared to other alternatives. On average, the electric trucks have slightly more greenhouse emissions and energy consumption than those of other trucks. The regional analysis also indicates that the percentage of cleaner power sources in the electricity mix plays an important role in the life cycle greenhouse gas emission impacts of electric trucks.

Actual Emissions from Urban Buses Powered with Diesel and Gas Engines

Abstract: Due to the growing demand for traditionally sourced fossil fuels such as oil or natural gas, it became necessary to search for new unconventional sources of these raw materials. The latest results of research work targeted the exploration and exploitation of resources of yet another type of fuel – shale gas. According to estimates, Poland alone may have reserves of 5.3 billion cubic meters of natural gas, accumulated in non-conventional sources. This potential can be used in many sectors of the economy, including in transport. Thus, it became reasonable to consider the use of natural gas as an alternative power source for vehicles. The article presents the results of emissions from public buses powered by diesel fuel and compressed natural gas. The study was conducted in real traffic conditions on a regular bus line in Poznan. The measurement of toxic exhaust elements was conducted with the use of a mobile measuring system of exhaust gas analyzers PEMS (Portable Emissions Measurement System). The data obtained were used to determine the average emissions of individual components. Based on the obtained values it can be concluded that the use of different types of fuels to drive public transport vehicles leads to a reduction of air pollutants and thus to improvement in the quality of life in the city.

Hydrogen admixture to the natural gas grid

Abstract: It is becoming more widely accepted that hydrogen could become an important energy carrier in the quest for sustainability because it offers several benefits related particularly to the potential for energy storage. Natural gas pipelines can potentially offer a solution to the storage problem by accepting and transporting small quantities of hydrogen, up to 10 vol%, mixed with the natural gas. However for this approach to be accepted by both the gas industry and the public, the end result must be a technically feasible, economically viable and, crucially, safe system for storage, transportation, and utilization. It’s clear that the European natural gas pipeline network has the potential to offer such a solution in what is known as power-to-gas (P2G) and several studies have examined the feasibility of using it as a means of widespread hydrogen storage and transportation. They have concluded that the volume of hydrogen that may be added to natural gas is limited and, with certain restrictions, admixture of up to 10 vol% is in general not critical, although a case-by-case analysis is necessary before injecting hydrogen in the natural gas network. There are however some crucial aspects in the interaction between hydrogen and the wider natural gas network for which additional R&D will be necessary to achieve a robust solution before this practice can be introduced universally, in particular: compressed natural gas tanks, gas turbines, and underground storage. It’s clear that P2G can offer viable storage solutions to the expensive and uncomfortable problems of over-production of renewably generated electricity and Europe could benefit significantly from using the enormous storage capacity of the European natural gas system. A considerable amount of R&D will be necessary to bring this to fruition, however, many believe that P2G can provide a significant storage solution and have already begun to act.

Prospects of and Problems in Using Natural Gas for Motor Transport in RUSSIA

Abstract: This article is devoted to increasing the use of natural gas in Russia as a measure to decrease the negative influence of motor transport on the environment. A brief analysis of the global fleet of natural gas vehicles is provided above. The documents accepted in Russia to promote public awareness of compressed natural gas in transport are submitted. The basic reasons keeping the growth of natural gas vehicle fleets in Russia consist of weak branching of refuelling stations; difficulty in determining the actual amount of compressed natural gas required; and control methods of the consumption of gas fuel. The offers promoting the growth of the fleet of natural gas vehicles are given.

The Potential Reduction of Carbon Dioxide (CO2) Emissions from Gas Flaring in Nigeria’s Oil and Gas Industry through Alternative Productive Use

Abstract: Globally, climate change and its adverse effects on the human population and the environment has necessitated significant research on the sustainable use of natural resources. Gas flaring in Nigeria’s oil and gas industry causes environmental and health hazards and to a large extent, culminates in yearly loss of the Nation’s revenue. The aim of the study is to highlight the potentials of converting flared gas from the Nigerian oil and gas industry to compressed natural gas (CNG) which could be an alternative fuel for the 220 Lagos Bus Rapid Transit (BRT-Lite) while reducing CO2 emissions. In addition, the study provided an overview of gas flaring in the oil and gas industry and energy utilisation in some selected sectors in the country. The Long-range Energy Alternative Planning System (LEAP) software was employed to model the energy demand and carbon dioxide emissions from the BRT-Lite by creating a current scenario and projections to the year 2030. The use of CNG as an alternative fuel for Lagos BRT-Lite will significantly reduce CO2 emissions in Nigeria’s oil and gas industry. Other utilization options for flared gas from this industry includes: Liquefied Natural Gas (LNG), Liquefied Petroleum Gas (LPG), and power generation.

Adsorption technology for the storage of natural gas and biomethane from biogas

Abstract: Summary As natural gas, biogas has been used for nobler purposes in recent years, such as the use of purified biogas (biomethane) in the transport sector. Currently, natural gas storage for use in transportation is accomplished primarily through compressed natural gas (CNG) technologies and liquefied natural gas (LNG), which require large amounts of energy. In recent years, the storage technology of absorbed natural gas (ANG) on porous materials has been studied, fundamentally highlighted by reduced energy use and increased safety in the transport of gaseous fuel. In this sense, the present study aimed to gather information about the main adsorbent materials which are being studied and the conditions normally employed in surveys that use ANG technology, as well as pointing out the main challenges for the storage of biogas in the adsorbed form at low pressures and room temperature in an attempt to meet the target of 180 V/V established by Department of Energy. Researchers reported high storage capacities in moderate conditions of temperature and pressure; however, the biggest challenge of the research involving methane adsorbed is also achieving high rates of desorption with the lowest possible energy expenditure. Copyright © 2016 John Wiley & Sons, Ltd.

Blended hydrogen–natural gas-fueled internal combustion engines and fueling infrastructure

Abstract: Many different blends of conventional and alternative fuels have previously been investigated to gain advantages of lower tailpipe and greenhouse gas emissions while reducing petroleum dependence. In particular, blends of hydrogen with compressed natural gas (HCNG, H2CNG, and Hythane®) have demonstrated advantages of lower tailpipe emissions and in some cases higher fuel economy. HCNG with hydrogen concentrations from 0% to 20% by volume can be run in conventional gasoline engines without retuning. HCNG with concentrations of hydrogen above 20% require engine retuning and low swirl intakes to run optimally. Achieving low levels of unburned methane emissions is a significant challenge for most conventional fuels without hydrogen enrichment. Hydrogen enrichment in HCNG blends promotes rapid and more complete combustion of methane by providing an abundance of hydroxyl ions, greatly reducing fugitive methane tailpipe emissions. HCNG engines are largely unaffected by carbon monoxide (CO) contamination in fuel, while by comparison hydrogen proton exchange membrane (PEM) fuel cells are permanently damaged by CO contamination as low as 10 ppm. HCNG borrows heavily from existing technology for CNG and hydrogen engines, storage, and dispensing stations. An exception is the need for a specialized hydrogen and natural gas blending unit before or after compression. HCNG achieves higher energy storage density than hydrogen within the same tank volume and pressure. Therefore, HCNG engine-powered vehicles deliver significantly greater range compared to hydrogen engine-powered vehicles with equivalent onboard storage tank volume. HCNG vehicles and fueling infrastructure have been successfully demonstrated across the globe in a number of transit and light vehicle fleets. HCNG-fueling infrastructure is usually deployed in stations where hydrogen and compressed natural gas fueling already exist. Use of HCNG can help accelerate the early market growth for hydrogen prior to widespread deployment of fuel cell vehicles and hydrogen-fueling infrastructure.

Safety issues associated with the use and operation of natural gas vehicles: learning from accidents in Pakistan

Abstract: The use natural gas in transportation is well established globally with over 18 million natural gas vehicles (NGVs) distributed through more than 90 countries of the world. This paper discusses several safety issues involved with using natural gas as a transportation fuel. After introducing the NGVs safety aspects and reviewing various standards for compressed natural gas (CNG) system, the paper discusses the 55 CNG-related accidents in Pakistan (which conduced to over 250 casualties) and analyzes the causes for these accidents and extracts “lessons to be learned” for CNG. The analysis reveals that due to low-quality CNG system material, e.g., CNG cylinder, CNG design and installation, maintenance system, etc., lack of strict government CNG vehicle safety regulations and driver negligence every year several CNG vehicles’ accidents took place in Pakistan which showed a major threat to life in Pakistan.

Compressed Natural Gas Vehicles: Financially Viable Option?

Abstract: Natural gas vehicles are being developed because of increasing concerns about energy dependence, air quality and emissions, and, more recently, climate change. The major advantage of natural gas vehicles is their lower fuel cost. Several economic and technical factors such as limited range and availability of relevant infrastructure prevent widespread adoption of natural gas vehicles. A model for the financial analysis of the possibility of compressed natural gas (CNG) vehicles being competitive with gasoline-powered vehicles is offered. The model evaluates the extent to which commuters find adoption of CNG vehicles to be economically viable in the United States. The results indicate that the percentage of commuters who would adopt CNG vehicles is small, even if fueling infrastructure were fully developed and CNG vehicles were widely available for purchase. A larger number of vehicle miles traveled and increased gasoline prices encourage commuters to adopt CNG vehicles, while higher fuel economy and purch...

Expolration of compressed natural gas as an automotive fuel in Nigeria

Abstract: Flaring of associated gas, found during petroleum exploration and production in Nigeria, results in substantial environmental degradation, which endangers sustainable development and exposes the population to health hazards. In addition, it results in significant economic losses, especially from the opportunity cost of the disposed natural gas (NG). As part of the many initiatives to abate flaring and harness NG resources, the Nigerian government proposed the use of compressed natural gas (CNG) as an automotive fuel in 1997, but progress has been slow. This study investigates the barriers to use of CNG as an automotive fuel in Nigeria and how these can be overcome. It identified, validated, prioritized and built consensus on 29 barriers and 25 policy recommendations, using a combination of case study of selected countries, semi-structured interviews and a Delphi survey among participants who are key stakeholders in the energy and transportation sectors. Major hindrances identified include the absence of market coordination; lack of transparency and accountability; inexperience of the population with gas usage; lack of public awareness on the benefits of NG; artificial distortion of the economic benefits of CNG due to the subsidy on gasoline; focus on export market development to the detriment of the domestic market; absence of regulatory standards; poor infrastructure; and an old and dilapidated national vehicle fleet. There was no convergence on the impact of insecurity of human and material resources caused by militancy and pipeline vandalism in the oil producing areas, despite widespread views of the negative effect on the oil and gas industry generally. Based on the consensus built among study participants, the study recommends 12 policy interventions, which might stimulate growth in the use of CNG as automotive fuel; these comprise specific energy market reforms, fiscal and operational incentives, transportation sector reforms and the creation/building of public awareness.

Gaseous emissions from compressed natural gas buses in urban road and highway tests in China

Abstract: The natural gas vehicle market is rapidly developing throughout the world, and the majority of such vehicles operate on compressed natural gas (CNG). However, most studies on the emission characteristics of CNG vehicles rely on laboratory chassis dynamometer measurements, which do not accurately represent actual road driving conditions. To further investigate the emission characteristics of CNG vehicles, two CNG city buses and two CNG coaches were tested on public urban roads and highway sections. Our results show that when speeds of 0–10 km/hr were increased to 10–20 km/hr, the CO 2 , CO, nitrogen oxide (NO x ), and total hydrocarbon (THC) emission factors decreased by (71.6 ± 4.3)%, (65.6 ± 9.5)%, (64.9 ± 9.2)% and (67.8 ± 0.3)%, respectively. In this study, The Beijing city buses with stricter emission standards (Euro IV) did not have lower emission factors than the Chongqing coaches with Euro II emission standards. Both the higher emission factors at 0–10 km/hr speeds and the higher percentage of driving in the low-speed regime during the entire road cycle may have contributed to the higher CO 2 and CO emission factors of these city buses. Additionally, compared with the emission factors produced in the urban road tests, the CO emission factors of the CNG buses in highway tests decreased the most (by 83.2%), followed by the THC emission factors, which decreased by 67.1%.

Impact of non-petroleum vehicle fuel economy on GHG mitigation potential

Abstract: The fuel economy of gasoline vehicles will increase to meet 2025 corporate average fuel economy standards (CAFE). However, dedicated compressed natural gas (CNG) and battery electric vehicles (BEV) already exceed future CAFE fuel economy targets because only 15% of non-petroleum energy use is accounted for when determining compliance. This study aims to inform stakeholders about the potential impact of CAFE on life cycle greenhouse gas (GHG) emissions, should non-petroleum fuel vehicles displace increasingly fuel efficient petroleum vehicles. The well-to-wheel GHG emissions of a set of hypothetical model year 2025 light-duty vehicles are estimated. A reference gasoline vehicle is designed to meet the 2025 fuel economy target within CAFE, and is compared to a set of dedicated CNG vehicles and BEVs with different fuel economy ratings, but all vehicles meet or exceed the fuel economy target due to the policy's dedicated non-petroleum fuel vehicle incentives. Ownership costs and BEV driving ranges are estimated to provide context, as these can influence automaker and consumer decisions. The results show that CNG vehicles that have lower ownership costs than gasoline vehicles and BEVs with long distance driving ranges can exceed the 2025 CAFE fuel economy target. However, this could lead to lower efficiency CNG vehicles and heavier BEVs that have higher well-to-wheel GHG emissions than gasoline vehicles on a per km basis, even if the non-petroleum energy source is less carbon intensive on an energy equivalent basis. These changes could influence the effectiveness of low carbon fuel standards and are not precluded by the light-duty vehicle GHG emissions standards, which regulate tailpipe but not fuel production emissions.

Methods of estimating energy demand and co2 emissions for inter-regional road transport

Abstract: Carbon dioxide (CO2) from the transport sector is by far considered as the major contributor of Greenhouse Gas (GHG) emission into the atmosphere. Many transport engineers and planners nowadays have shifted focus on the development of new approaches or tools that provide fast and reliable means of assessing different transportation strategies to achieve low-carbon transportation system. In this study, a new mathematical Origin-Destination (O-D) approach of estimating energy demand and CO2 emissions is presented using inter-regional passenger and freight flow data. The lengths of three major road segments were used as independent variables to model fuel consumption for buses and trucks. The estimated energy demand under business as usual (BAU) scenario was compared to five different low-carbon policy scenarios. Study shows that the energy demand from inter-regional public buses and freight road transport under BAU scenario substantially increased from 6,358.86ktoe in 2015 to 36,410.43ktoe in 2050. These findings equate to 19.71 and 112.93 Megatons of CO2 emissions in 2015 and 2050, respectively. Results also show that shifting to low-carbon alternative fuel such as Compressed Natural Gas (CNG) for buses and trucks provide the highest reduction in the overall inter-regional CO2 emissions as compared other policy measures. Simultaneous implementation of the three selected policy measures would substantially reduce the CO2 emissions by almost two-third (74.24%) in 2050.

Thermodynamic investigation of different natural gas combustion processes on the basis of a heavy-duty engine

Abstract: The main challenges in engine development are the compliance to the stringent and constantly tightened emission limits and the reduction in the CO2 release. Natural gas as fuel offers one possible ...

System and method for controlling air-fuel ratio of cng engine

Abstract: A system includes a compressed natural gas (CNG) engine, a three-way catalyst (TWC), a first oxygen sensor connected to the CNG engine, and a second oxygen sensor connected to the three-way catalyst. A method for controlling an air-fuel ratio of the CNG engine includes determining whether or not the CNG engine and the three-way catalyst are normal by measuring output voltages of the first and second oxygen sensors, determining whether or not the three-way catalyst is aged, and adjusting the air-fuel ratio of the CNG engine based on a result of the step of determining whether or not the three-way catalyst is aged

Net greenhouse gas emissions savings from natural gas substitutions in vehicles, furnaces, and power plants

Abstract: We compare the net greenhouse gas emissions impact of substituting natural gas for other fossil fuels for five purposes: light-duty vehicles, transit buses, residential heating, electricity generation, and export for electricity generation overseas. Emissions are evaluated on a fuel cycle basis, from production and transport of each fuel through end use combustion, based on recent conditions in the USA. To compare across sectors, the emissions difference between natural gas and its alternative is normalised by natural gas consumption to compute the net reduction in CO2e per MJ of natural gas used. Greatest emission reductions can be achieved by replacing existing coal-fired power plants (78gCO2-e/MJ natural gas) or fuel oil furnaces (66gCO2e/MJNG). Compressed natural gas in vehicles yields no significant reductions. Uncertainties arising from upstream emission rates for natural gas and the global warming potential of methane are quantified. The study demonstrates the critical role of deployment choice on the net climate impact of natural gas.

Environmental impacts of hydrogen use in vehicles

Abstract: This chapter concentrates on a life cycle assessment (LCA) of hydrogen mobility options compared to other alternative and “classical” options regarding greenhouse gas emissions and acidifying emissions. This LCA includes the fuel production (i.e., hydrogen from natural gas, hard coal, electricity, and biomass as well as diesel and biodiesel, compressed natural gas and electricity), fuel distribution and its usage in correspondent vehicles (i.e., fuel cell electric, battery-electric electric, natural gas and diesel driven vehicle). In addition also the production of the vehicles is taken into account.

Development and application of a control scheme to reduce insufficient operation of an NG-diesel dual-fuel automobile

Abstract: The thermal efficiency levels are generally maintained while the smoke emission levels are reduced significantly with natural-gas–diesel dual-fuel operation in comparison with those with diesel operation. Thus, the dual-fuel mode is a good choice for in-use vehicles to reduce the smoke emissions and the fuel cost. However, the higher hydrocarbon and carbon monoxide emissions compared with those for traditional diesel operation under low loads is a concern. In this paper, a control scheme is proposed to reduce insufficient operation in the natural-gas–diesel dual-fuel mode. Also, a control system, including a control unit and actuating devices, is developed to realize the scheme. The responses of the governor lever, the smoke emissions of the vehicle and the fuel consumption values are compared and analyzed. The test results show that the response of the governor lever is sufficient for practical applications, as it is able to follow the pedal stroke instantaneously with good accuracy. The lugdown smoke emissions of the diesel mode do not conform to those given in the Chinese Standard GB 3847-2005, but those of the dual-fuel mode do. In the road tests, the substitution ratio of liquefied natural gas to diesel is 61.36%, and the fuel cost saving ratio is up to 21.71%. Overall, the scheme and the electronic control device work reliably and can be applied to both liquefied natural gas and compressed natural gas as gaseous fuels.

Case Study: Natural Gas Regional Transport Trucks

Abstract: Learn about Ryder System, Inc.'s experience in deploying nearly 200 CNG and LNG heavy-duty trucks and construction and operation of L/CNG stations using ARRA funds. Using natural gas in its fleet, Ryder mitigated the effects of volatile fuel pricing and reduced lifecycle GHGs by 20% and petroleum by 99%.