Showing papers on "Compressed natural gas published in 2010"

Examining the benefits of using bio-CNG in urban bus operations

Abstract: Public service fleets offer an attractive option for introducing new renewable fuels on a large scale, which allow for the reduction of both greenhouse gas emissions and exhaust air pollutants. This study examines the use of biomethane (bio-CNG) and compressed natural gas for part of the bus fleet in Dublin, Ireland. The emissions produced from the 2008 fleet based at one of the city’s seven bus depots are compared to use of new diesel and bio-CNG buses. The optimum feedstock for bio-CNG production in Ireland was then investigated, as well as the quantity of feedstock needed to produce the required bio-CNG to fuel the bus fleet examined. As expected the results showed a substantial decrease in all exhaust emissions from the use of bio-CNG buses compared the 2008 fleet. Grass silage was chosen as the optimum feedstock for production of bio-CNG in Ireland.

Business Case for Compressed Natural Gas in Municipal Fleets

Abstract: This report describes how NREL used the CNG Vehicle and Infrastructure Cash-Flow Evaluation (VICE) model to establish guidance for fleets making decisions about using compressed natural gas.

Critical analysis of high particle number emissions from accelerating compressed natural gas buses

Abstract: Compressed natural gas (CNG) engines are thought to be less harmful to the environment than conventional diesel engines, especially in terms of particle emissions. Although, this is true with respect to particulate matter (PM) emissions, results of particle number (PN) emission comparisons have been inconclusive. In this study, results of on-road and dynamometer studies of buses were used to derive several important conclusions. We show that, although PN emissions from CNG buses are significantly lower than from diesel buses at low engine power, they become comparable at high power. For diesel buses, PN emissions are not significantly different between acceleration and operation at steady maximum power. However, the corresponding PN emissions from CNG buses when accelerating are an order of magnitude greater than when operating at steady maximum power. During acceleration under heavy load, PN emissions from CNG buses are an order of magnitude higher than from diesel buses. The particles emitted from CNG buses are too small to contribute to PM10 emissions or contribute to a reduction of visibility, and may consist of semivolatile nanoparticles.

Carbon dioxide emissions from diesel and compressed natural gas buses during acceleration

Abstract: Motor vehicle emission factors are generally derived from driving tests mimicking steady state conditions or transient drive cycles. Neither of these test conditions, however, completely represents real world driving conditions. In particular, they fail to determine emissions generated during the accelerating phase – a condition in which urban buses spend much of their time. We analyse and compare the results of time-dependant emission measurements conducted on diesel and compressed natural gas buses during an urban driving cycle on a chassis dynamometer and we derive power-law expressions relating carbon dioxide emission factors to the instantaneous speed while accelerating from rest. Emissions during acceleration are compared with that during steady speed operation.

Well-to-Wheels analysis of landfill gas-based pathways and their addition to the GREET model.

Abstract: Today, approximately 300 million standard cubic ft/day (mmscfd) of natural gas and 1600 MW of electricity are produced from the decomposition of organic waste at 519 U.S. landfills (EPA 2010a). Since landfill gas (LFG) is a renewable resource, this energy is considered renewable. When used as a vehicle fuel, compressed natural gas (CNG) produced from LFG consumes up to 185,000 Btu of fossil fuel and generates from 1.5 to 18.4 kg of carbon dioxide-equivalent (CO{sub 2}e) emissions per million Btu of fuel on a 'well-to-wheel' (WTW) basis. This compares with approximately 1.1 million Btu and 78.2 kg of CO{sub 2}e per million Btu for CNG from fossil natural gas and 1.2 million Btu and 97.5 kg of CO{sub 2}e per million Btu for petroleum gasoline. Because of the additional energy required for liquefaction, LFG-based liquefied natural gas (LNG) requires more fossil fuel (222,000-227,000 Btu/million Btu WTW) and generates more GHG emissions (approximately 22 kg CO{sub 2}e /MM Btu WTW) if grid electricity is used for the liquefaction process. However, if some of the LFG is used to generate electricity for gas cleanup and liquefaction (or compression, in the case of CNG), vehicle fuel produced from LFG can have no fossilmore » fuel input and only minimal GHG emissions (1.5-7.7 kg CO{sub 2}e /MM Btu) on a WTW basis. Thus, LFG-based natural gas can be one of the lowest GHG-emitting fuels for light- or heavy-duty vehicles. This report discusses the size and scope of biomethane resources from landfills and the pathways by which those resources can be turned into and utilized as vehicle fuel. It includes characterizations of the LFG stream and the processes used to convert low-Btu LFG into high-Btu renewable natural gas (RNG); documents the conversion efficiencies and losses of those processes, the choice of processes modeled in GREET, and other assumptions used to construct GREET pathways; and presents GREET results by pathway stage. GREET estimates of well-to-pump (WTP), pump-to-wheel (PTW), and WTW energy, fossil fuel, and GHG emissions for each LFG-based pathway are then summarized and compared with similar estimates for fossil natural gas and petroleum pathways.« less

A Study of Fuel Cell Hybrid Auto Rickshaws Using Realistic Urban Drive Cycles

Abstract: The popular three-wheeled vehicles known as auto rickshaws are common in Asian cities where due to their older twostroke engines they have been significant contributors to the current air quality issues that plague the urban areas. Recent changes to four-stroke engines as well as those powered by diesel, compressed natural gas (CNG) or liquefied petroleum gas (LPG) reduce the pollution and greenhouse gas emissions. However, because of the large number of vehicles emission of such vehicles is still an important issue. Some studies about converting an internal combustion engine (ICE) rickshaw to an electrical or fuel cell rickshaw have been done recently. Most of the rickshaw conversion studies used one of the standard urban drive cycles. Such drive cycles do not accurately portray the demands on a rickshaw. Thus, results with unrealistic drive cycles may be misleading. In this study a comparison between ICE and hybrid fuel cell rickshaw configuration was done using a realistic drive cycle. An ICE and two candidate fuel cell rickshaw models were created and assessed using the Powertrain System Analysis Toolkit (PSAT) software. Two drive cycles that would closely emulate the true demands on a rickshaw operated in an urban environment were developed in order to more accurately simulate the performance of conventional and fuel cell hybrid rickshaws as a means of determining the current feasibility of fuel cells for use in rickshaws .

In quest for a sustainable motorisation: the CNG opportunity

Abstract: This article describes the opportunity deriving from the substitution of conventional fuels with the compressed natural gas (CNG). The advantages of this fuel are: a) relevant, as it concerns consumer's expenses and ecological aspect; b) rapidly achievable; c) close to hand for Europe, the USA and other countries where the motorisation is at the take-off stage, like the BRIC countries and Iran, Pakistan, Indonesia and so on. These advantages makes CNG a viable solution, with relevant advantages both on the side of pollution and expenses, while waiting for the availability of new technologies. Presently, the most important bottleneck for a large-scale implementation of this solution is represented by a possible shortage in the distribution network. Those countries crossed by gas pipeline could rapidly overcome this bottleneck without relevant costs. Otherwise, the solution could be achieved either through gas carrier's ships or through local production of biomethane by the exploitation of biomasses.

In quest for a sustainable motorization: the CNG opportunity

Abstract: This article aims at describing the opportunity deriving from the substitution of conventional fuels, as gasoline and diesel, with the Compressed Natural Gas (CNG), frequently indicated as methane. The use of CNG systems in vehicles cannot be considered the ultimate solution to the problem of pollution generated by road transport, but the advantages of this fuel are: a) relevant, as it concerns consumer’s expenses and ecological aspect; b) rapidly achievable, waiting for availability of new technologies capable of more relevant advantages; c) close to hand for several countries: Europe and U.S. and those where the motorization is at the take-off stage, like the BRIC countries (Brazil, Russia, India, China), and others like: Iran, Pakistan, Indonesia and so on. In fact, such countries in take-off stage on the one hand have extensive reserves of methane, and on the other hand need to cut emission urgently, specifically in areas with a high density of population. From the economic point of view CNG results a viable solution with few contraindication. The most important bottleneck is represented by a possible shortage in the distribution network. If a country is crossed by a gas pipeline this shortage could be overcome rapidly and without relevant costs. In the others the solution could be achieved either through gas carriers ships or through local production of biomethane by the exploitation of biomasses.

Compressed Natural Gas (CNG) Transit Bus Experience Survey: April 2009--April 2010

Abstract: This survey was commissioned by the U.S. Department of Energy (DOE) and the National Renewable Energy Laboratory (NREL) to collect and analyze experiential data and information from a cross-section of U.S. transit agencies with varying degrees of compressed natural gas (CNG) bus and station experience. This information will be used to assist DOE and NREL in determining areas of success and areas where further technical or other assistance might be required, and to assist them in focusing on areas judged by the CNG transit community as priority items.

Assessment of the environmental effects of the compressed natural gas bus fleet in Beijing

Abstract: Based on an investigation of the bus fleet configuration and operation situation in Beijing in 2007,we identified that Euro III and Euro IV vehicles are the most common bus models The modified COPERT IV model was used to estimate emission factors for gasoline,diesel and compressed natural gas (CNG) buses meeting different emission control standards in Beijing The PM25 and NOx emission factors of the Euro III CNG bus are reduced by 97% and 30% as compared to the Euro III diesel bus The PM25 and NOx emission factors of enhanced environmentally-friendly vehicle (EEV) CNG buses are reduced by 93% and 69% as compared to the Euro IV diesel bus Because the CH4 emission factor of CNG buses is much higher than diesel buses,the THC emission factor of a CNG bus is significantly higher than a diesel bus of similar control standard A bus emission inventory was built based on these emission factors The bus emissions in Beijing in 2007 were 9051 t CO,955 t NMHC,1222 t THC,8553 t NOx and 161 t PM25 By using CNG buses,the emission of CO,NMHC,NOx and PM25 has been reduced by 293 t,62 t,775 t and 33 t,or 31%,61%,83% and 172% of total bus emissions,respectively In 2007,the operation of CNG buses has reduced diesel consumption by 50×104 t,which is 26% of the total diesel consumption in Beijing And the CO2 equivalent of greenhouse gas emissions of Beijing buses in 2007 was 83×105 t; 24% higher than the scenario without CNG buses

Commercial Vehicles in Delhi: Diesel Demand and Sulphur Emission

Abstract: The aim of this paper is to estimate the future growth of commercial vehicles (passenger vehicles and goods vehicles) and to project the subsequent increase in diesel demand and the level of sulphur dioxide emissions in Delhi. Using an S-curve growth model on the data set of auto rickshaws, taxis, buses, and goods vehicles from 1965- 66 to 2005-06, a long-term trend in the growth of commercial vehicles is projected to the year 2020-21. By 2020-21, the number of commercial vehicles is expected to increase to 0.51 million, with an increase in the share of goods vehicles and a simultaneous decrease in the share of passenger vehicles. The growth of commercial vehicles will boost the demand for diesel in 2020-21 by 68 percent, thus resulting in a threefold increase in sulphur dioxide emissions. The conversion of goods vehicle engines from diesel to CNG (compressed natural gas) will reduce diesel demand and sulphur dioxide levels significantly. A reduction of sulphur content in diesel can further reduce sulphur dioxide emissions.

Volatile organic compounds in a residential and commercial urban area with a diesel, compressed natural gas and oxygenated gasoline vehicular fleet.

Abstract: Air samples were collected in a typical residential and commercial area in Rio de Janeiro, Brazil, where buses and trucks use diesel and light duty vehicles use compressed natural gas, ethanol, and gasohol (gasoline blended with ethanol) as fuel. A total of 66 C3–C12 volatile organic compounds (VOCs) were identified. The most abundant compounds, on a mass concentration basis, included propane, isobutane, i-pentane, m,p-xylene, 1,3,5-trimethylbenzene, toluene, styrene, ethylbenzene, isopropylbenzene, o-xylene and 1,2,4-trimethylbenzene. Two VOCs photochemical reactivity rankings are presented: one involves reaction with OH and the other involves production of ozone.

Composite pressure container and method of manufacturing the same

Abstract: The present invention concerns a light weight composite pressure container for fluids adapted to hold fluids under both high and low pressures, such as H 2 , industrial gases, CNG (compressed natural gas) and LPG (liquefied petroleum gas), as well as a method of manufacturing the same.

Storage and transport method of cng by a container ship, and manifold apparatus for loading and unloading of gas using thereof

Abstract: PURPOSE: A storage method and a transfer method for compressed natural gas using a container ship, and a manifold device for loading and unloading of gas using the same are provided to supply natural gas even if a large scale storage place for natural gas is not secured CONSTITUTION: A storage method and a transfer method for compressed natural gas using a container ship are as follows A compressed natural gas module is loaded on a container ship(S1) The natural gas is compressed, stored, and loaded by moving the container ship to a production area(S2) The natural gas is supplied by moving the container ship in which the compressed natural gas is loaded to a port of a consumption area(S3) The natural gas is supplied to a factory or a habitation site through a compressed natural gas pipe line At the same time, movable charge of the natural gas is performed

The role of natural gas as a vehicle transportation fuel

Abstract: This thesis analyzes pathways to directly use natural gas, as compressed natural gas (CNG) or liquefied natural gas (LNG), in the transportation sector. The thesis focuses on identifying opportunities to reduce market barriers in order to make the US natural gas vehicle market more efficient. We also identify vehicle market segments where NGV technology is mature and does not require sustained public subsidy to economically compete with comparable gasoline or diesel vehicles. This thesis finds that natural gas can play a useful but modest role as a vehicle fuel in the US, predominantly as CNG in high-mileage, light-duty fleet vehicles and in heavy-duty, short-haul fleet vehicles. For light-duty applications, there is a need to address an existing market barrier in the US by reducing the incremental cost and improving the vehicle performance of CNG vehicles to levels found in Europe. This incremental cost reduction is critical to foster market penetration in high-mileage fleet vehicles and to create a potential opportunity for market penetration beyond high-mileage fleet vehicles to average-mileage individual drivers. Increased use of CNG in light duty vehicles would displace petroleum, reduce greenhouse gas emissions in the transportation sector, and hedge consumers from volatile world oil prices (if CNG is used in a bi-fuel - gasoline and CNG- vehicle). In the heavy-duty, short-haul sector, CNG provides an additional benefit of reduced nitrogen oxide emissions compared to diesel trucks. With respect to long-haul LNG trucks, this thesis finds that while there is a large potential market for natural gas in the long-haul truck market, the present prospects for the use of LNGpowered long haul trucks appears quite limited. This is due to high incremental costs, unresolved operational issues, fueling infrastructure requirements, and reluctance of the trucking industry.

Equipment producing compressed natural gas from mixed gas containing methane

Abstract: The utility model discloses equipment producing compressed natural gas from mixed gas containing methane, comprising a refrigeration device, a mixed gas containing methane separation device, a cryogenic liquid pump and a high-pressure heat exchanger. Mixed gas containing methane becomes liquefied natural gas after sequentially entering the refrigeration device and the mixed gas containing methane separation device, and then enters the cryogenic liquid pump for pressurization to become high-pressure liquefied natural gas. After entering the high-pressure heat exchanger for re-warming gasification, the high-pressure liquefied natural gas directly becomes a compressed natural gas product for storage and filling, so a complex device using a compressor to compress and cool low-pressure natural gas into the compressed natural gas is saved. The purity of the compressed natural gas product obtained by the equipment can reach over 99.8%, the whole set equipment is simple, and the operation is easy.

Tank container for oil field gas or compressed natural gas

Abstract: The utility model relates to a tank container for compressed oil field gas or compressed natural gas, which comprises a container, wherein a single tank for the compressed oil field gas or the compressed natural gas is arranged in the container. The utility model has the advantages that because the tank container for the compressed oil field gas or the compressed natural gas is formed by placing the single tank for the compressed oil field gas or the compressed natural gas in the container, the tank container can be put on a semi-trailer for land transportation and can also be suspended on a ship for water transportation, thereby realizing the combined transportation by landway and waterway and being convenient for transportation and also being safe and reliable.

Prospect of CNG Vehicle Development in Shanghai, China

Abstract: Compressed Natural Gas (CNG) is a clean substitute fuel for vehicle with broad application prospect, due to its enormous advantage in resource, environment and economy. This paper investigated development of CNG vehicle in Shanghai. Main factors constraining CNG vehicle application in Shanghai were scarcity of gas resource and gas station, declining in power performance and higher original investment CNG vehicle in Shanghai has broad prospect. CNG vehicle showed remarkable economic benefit. Calculation showed obvious reduction in fuel cost, 77.71 million RMB and 158.35 million RMB per year with 50% and 100% fuel replacing by CNG for public bus in Shanghai, while 129.42 million and 258.71 million RMB with 50% and 100% fuel replacing for taxi. Sufficient gas resource supply will be guaranteed, estimating 10 billion m3 totally in 2011. Positive policies are initiated by the government. Development of related technologies strongly supports its application. However, further improvements on CNG engine, gas station and government policy are essential.

A replacement kit for installing a compressed natural gas (cng)/fuel dual system for motorcycles

Abstract: A kit for installing a compressed natural gas (CNG)/fuel dual system in replacement of a conventional fuel system in a motorcycle, wherein the kit comprises a base support to fix to a motorcycle chassis, with the base support including a compressed natural gas container firmly affixed to the support, a gas pressure regulator to regulate the pressure of gas from the container towards a carburetor and a gas diffuser for feeding the gas into the carburetor

Analysis of alternative energy sources for the united states Roadway Transportation System

Abstract: Over the last decade, the U.S. transportation industry has produced approximately 60% of overall U.S. CO 2 emissions according to the U.S. Department of Transportation (DOT). A greener fuel alternative for the transportation system is needed to reduce energy-related emissions and to aid in the overall decrease in the consumption of fossil fuels. The system to be analyzed is defined as the Roadway Transportation System (RTS) of the United States. This project aims to rank six alternative fuels against several objectives for the next 30 years. These objectives include minimizing emissions and risk, while maximizing suitability and goods moved. Six alternatives are considered: gasoline, diesel, biodiesel, electric, hydrogen, and compressed natural gas (CNG) technologies. The capability and feasibility of each alternative is analyzed in accordance with satisfying all objectives. This system analysis is limited to cars, trucks, and buses. An External System Model (ESM) is developed to show the interactions of the RTS with external systems, and how those interactions map to the traceability of all objectives (1st model). To conduct this analysis, data from previous years is collected for all objectives for each alternative. Regression of this data identifies the pattern of the alternatives against the objectives over time (2nd model). Ranking of the alternatives is accomplished through Utility Evaluation (3rd model). The ranking process follows the Multi Attribute Utility Theory (MAUT) process. Preliminary results show that there is uncertainty as to which alternative is best when weighed against the given objectives. However, electric and CNG rank the highest under pessimistic assumptions and electric and hydrogen rank highest under optimistic assumptions. Through analysis, all alternatives are ranked such that the objectives are satisfied over a 30 year period.

Carbon dioxide emissions from diesel and compressed natural gas buses during acceleration

Abstract: Motor vehicle emission factors are generally derived from driving tests mimicking steady state conditions or transient drive cycles. However, neither of these test conditions completely represents real world driving conditions. In particular, they fail to determine emissions generated during the accelerating phase – a condition in which urban buses spend much of their time. In this study we analyse and compare the results of time-dependant emission measurements conducted on diesel and compressed natural gas (CNG) buses during an urban driving cycle on a chassis dynamometer and we derive power-law expressions relating carbon dioxide (CO2) emission factors to the instantaneous speed while accelerating from rest. Emissions during acceleration are compared with that during steady speed operation. These results have important implications for emission modelling particularly under congested traffic conditions.

Refuelling safety method and device for a vehicle fuelled with gas transportation fuel, such as cng, lpg, hydrogen

Abstract: The present invention relates to a refuelling safety method for a vehicle fuelled with gas transportation fuel, such as CNG (Compressed Natural Gas) or LPG (Liquefied Petroleum Gas) or hydrogen, which provides the engine stopping in case of opening of the fuel filler neck closing element on the vehicle tank when the vehicle is stationary. Moreover with vehicle speed below a threshold, if the closing element is open, the engine is stopped; with vehicle speed higher than a threshold, the engine is left on regardless of the open or closed condition of the closing element.

Evaluation of a two stroke compressed natural gas mixer design by simulation and experimental techniques

Abstract: Natural gas is a viable alternative fuel that is able to reduce tailpipe emission, most notably in two stroke engines it is available in compressed form or Compressed Natural Gas (CNG) for easy storage. The excessive by-products of two-stroke engine combustion; normally due to inefficient combustion process is largely attributed to high particulate, carbon monoxide and hydrocarbon constituents. A prototype uniflow-type single-cylinder engine was equipped with a bi-fuel conversion system were used for the work. A dedicated mixer was also developed to meter the gaseous fuel through the engine intake system. It was designed to meet the air and fuel requirement similar to the gasoline counterpart. Modeling of the mixer was made to obtain optimum orifice diameter using three different sizes of 14, 16 and 18mm respectively. Here, flow simulations using a standard Computational Fluid Dynamics (CFD) software were extensively used and the predicted results were subsequently validated using a dedicated a flow test rig. Pressure drop across the venturi is an important parameter as it determines the actual fuel-air ratio in the actual engine. A good agreement of CFD outputs with that of the experimental outputs was recorded. This paper highlights the work, which leads to the use of the dedicated CNG fuelling system in a general-purpose gasoline two-stroke engine.

Natural gas for ship propulsion in Denmark - Possibilities for using LNG and CNG on ferry and cargo routes

Abstract: The project's main task was to review logistical, technical and economic feasibility for using Liquefied Natural Gas (LNG) and Compressed Natural Gas (CNG) as fuel for ship propulsion and the supply of LNG or CNG to Danish ports from existing natural gas lines, trucks or by ship. The following key findings are related to the use of natural gas as fuel for ships in Denmark: Natural gas as propulsion fuel in ships: 1) Advantages: Provide solution to present air emission challenges 2) Barriers: Capital investments large 3) Synergies: Developments in Norway and Baltic Sea area 4) Economy: Positive case for operation for large consumers 5) Future: Develop bunkering options for short sea shipping LNG: 6) Propulsion technology in ships is mature and proven 7) Distribution network not yet developed for use in ships 8) Safety concerns are demanding but manageable 9) Can enter existing bunkering value chain CNG: 10) Well developed for land based transport, not yet for shipping 11) Distribution network for natural gas exists in Denmark 12) Safety concerns are demanding but manageable 13) No seaborne CNG value chains in operation An immediate focus on the ferry sector in Denmark will reap benefits on a relatively short time scale. For the short sea shipping sector away to promote the conversion to natural gas is to support the development of storage and bunkering facilities in main ports. Given the general expectations in the shipping community LNG will presumably be the de facto choice at least for the 5-10 years ahead and the demand for facilities and bunkers will be for LNG. (LN)