Alternate fuels propane

In the United States, in particular, recent legislation has mandated sweeping improvements to urban air quality by limiting mobile source emissions and by promoting cleaner fuels. The new laws require commercial and government fleets to purchase a substantial number of vehicles powered by an alternative fuel, such as natural gas, propane, electricity, methanol or ethanol. However, natural gas is usually preferred because of its lower cost and lower emissions compared with the other available alternative gas or liquid fuels. Even when compared with electricity, it has been shown that the full fuel cycle emissions, including those from production, conversion, and transportation of the fuel, are lower for an NGV [2]. Natural gas vehicles offer other advantages as well. Where natural gas is abundantly available as a domestic resource, increased use... 

The United States passed the Energy Policy Act in 1992. One goal was to reduce the amount of petroleum used for transportation by promoting the use of alternative fuels in cars and light trucks. These fuels included natural gas, methanol, ethanol, propane, electricity, and biodiesel. Alternative fuel vehicles (AFVs) can operate on these fuels and many are dual fueled also running on gasoline. 

Figure 9.3. Energy densities of various alternative fuels (LHY) (LPG 50% propane, 50% butane natural gas 83% methane).

Propane has been used as a vehicle fuel for at least the past 60 years in the U.S. It is by far the alternative fuel used in the largest volume in the U.S., estimated to be 97% of all alternative fuel use in 1992. The number of vehicles using propane as fuel has been estimated to be between 220,000 and 370,000 [1.24,1.25]. Nearly all these propane vehicles are conversions of gasoline vehicles, since the auto manufacturers have sold only very few propane vehicles. Even so, the consumption of these propane vehicles accounted for just 0.1% of all the gasoline-equivalent on-road motor fuel use in 1992. 

The UST regulations are being administered by each state. The state plans may differ in some respects to the general provisions listed in the previous paragraphs. USTs containing hazardous materials must have secondary containment. Of the alternative fuels covered in this book, methanol and ethanol must be stored in USTs having secondary containment. (Propane does not require secondary... 

LP gas, or propane, is the alternative fuel used in highest volume in the U.S. at present. Propane is unique among alternative fuels in that it is a pressurized liquid, i.e., a modest pressure (under 43.5 kPa [300 psi]) will maintain it in the liquid state. Propane fuel tanks must thus be built to pressure vessel codes like CNG and LNG tanks, but propane is transferred using pumps because pressure differentials are low and the pressure cannot be manipulated as it can for LNG. Propane is sometimes stored in refrigerated containers which lowers the storage pressure significantly, though such containers are rarely if ever used to store propane intended for use in vehicles. 

Fuel Availability Most of the E-85 fueling stations are located in the Midwest, but, in all, approximately 150 stations are available in 23 states. There are only a small number of hydrogen stations across the country. Most are available for private use only. Public LNG stations are limited (only 35 nationally), and LNG is available through several suppliers of cryogenic liquids. Propane is the most accessible alternative fuel in the U.S. There are more than 3,300 stations nationwide. Methanol remains a qualified alternative fuel as defined by EPAct, but it is not commonly used. 

LPG is a blend of propane and butane obtained as secondary products of natural-gas exploration or during crude oil processing. For this reason LPG is included usually in alternative fuels. Although the combustion properties of LPG are excellent, its wider usage is prevented by supply limitations and safety problems. 

Interest in the US focuses mainly on fuelling fleet vehicles, such as taxis and commercial transport the absence of any appreciable infrastructure effectively excludes privately owned automobiles. There were more than 333,000 alternative fuel vehicles (AFVs) in the United States in 1995, of which three quarters were vehicles designed to operate on LPG, primarily propane [59]. The use of AFVs is expected to continue to grow at a rate of about 7.6% per year. Natural gas fueled vehicles make up two-thirds of the non-LPG AFVs in use, or approximately 55,000 vehicles as of 1995. 

In the case of hydrogen, some of these obstacles are even more of a barrier than for other alternative fuels. Hydrogen fuel, when used in its compressed form, shares many similarities with compressed natural gas (CNG). When liquefied, it shares many similarities with liquefied natural gas (LNG) and liquefied petroleum gas (LPG), also called propane. In addition, hydrogen is costlier to compress and harder to store than any of these other alternative fuels. Hydrogen fuel vehicles may, in their early years, have low range, a negative attribute that currently limits use of battery electric vehicles (BEVs). 

Alternative Fuels - A popular term for "non-conventional" transportation fuels derived from natural gas (propane, compressed natural gas, methanol, etc.) or biomass materials (ethanol, methanol). 

The present alternate fuels in use today are propane, methanol, and ethanol. 

A number of other interesting uses have been foimd for polybenzimidazole membranes, including a propane fueled fuel cell, an alkaline based fuel ceU, a trimethoxymethane based fuel cell, and a quasi-direct methanol fuel cell. Wang et al. investigated trimethoxymethane (TMM) as an alternative fuel for a m-PBI direct oxidation fuel cell [77]. The oxidation of TMM was analyzed by an online mass spectrometer and onhne FTIR spectroscopy. The PBI membranes used in the TMM study were doped with 5 moles PA/PRU. The TMM was hydrolyzed to form a mixture of methylformate, methanol, and formic acid. At temperatures at or above 120 °C, the TMM hydrolyzed in the presence of water without an acid catalyst. The anode performance of the different fuels increased in the order of methanol < TMM < formic acid/methanol < methylformate. The improved performance of TMM over just methanol was most likely due to the electrochemical activity of formic acid. 

Dimethyl Ether Another potential alternative fuel is dimethyl ether (DME, CH3OCH3), presently used as an aerosol and propellant for spray paints and agricultural chemicals and cosmetics and a potential diesel fuel replacement [58, 59]. The storage and handling of DME is similar to standard propane DME can be stored as a liquid at 0.6 MPa in standard propane tanks, and it throttles to a gas at atmospheric pressure. This is similar to the fuel... 

Disposal. Moderate amounts of chlorine ttifluoride or other halogen fluorides may be destroyed by burning with a fuel such as natural gas, hydrogen, or propane. The resulting fumes may be vented to water or caustic scmbbers. Alternatively, they can be diluted with an inert gas and scmbbed in a caustic solution. Further information on disposal of halogen fluorides is available (115—118). 

Compared with other alternative motor fuel options (reformulated gasoline, compressed or liquefied natural gas, ethanol from corn or coal, methanol and electricity), propane has the lowest greenhouse gas emissions except for natural gas. According to a 1998 study by the Institute of Transportation Studies, greenhouse emissions from propane vehicles arc 21.8 percent less than from gasoline or diesel. 

One of the alternatives to natural gas is an industrial product such as propane or butane. These fuels are transported and stored in liquid form. On-site facilities are necessary for reception, off-loading and storage. 

Usually when anything heavier chan ethane—or sometimes heavier than propane—is cracked, there is a furnace designed to handle the ethane recycle stream. The plant shown in Figure 5-4 shows three heavy liquid furnaces and one ethane furnace. Since the alternate use for ethane is usually refinery fuel, the economics often dictate recovery and cracking. 

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