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gas from the well.  Marginal leakage is likely low.  Gas sweetening plants produce fugitive losses of heavy glycols.  These emissions translate to less than 0.2 g/100scf.  Methanol is used in drying systems for local compressors.  The volume of methanol is negligible.

LPG is shipped in 30,000 gal rail cars.  The fuel is transferred to 30,000 storage tanks either by pumping from the rail car or by 10,000 gal tanker trucks.  Fuel is delivered to local service stations in 3,000 gal trucks where it is stored in 1,000 gal tanks.  If LPG use for vehicles were to increase, the capacity of local delivery trucks and storage tanks would also increase.

3.6  Fuels from Remote Natural Gas

Synthetic diesel and other synthetic liquid fuels are formed from a three-step process (known as the Fischer-Tropsch [FT] process) which converts coal, biomass, or natural gas to liquid fuels.  It is an attractive air quality option to conventional fuels because it contains no sulfur or aromatics and has a higher cetane number.  This study considers only synthetic diesel from natural gas because it is the most economically attractive option.

As a result of this process, the fuel cycle for synthetic diesel at the upstream end is similar to compressed natural gas, and at the downstream end resembles diesel fuel.  Table 3-9 shows the steps associated with FTP production and distribution.

Table 3-9:  Synthetic Diesel Production and Distribution Phases

Phase

Process

Emission Sources

1

Extraction

Compressors, fugitive

2

Transport

Natural gas pipeline (compressors & fugitive)

3

Conversion

Fugitive emissions, vent gas combustion

4

Site storage

Fixed roof tanks

5

Transport to bulk storage

Tanker ships

6

Bulk storage

Floating roof tanks

7

Transport to local station

Tanker trucks (engines & fugitive)

8

Local station distribution

Underground tanks, refueling vapors and spillage

Methanol, like synthetic diesel, can be produced from a variety of feedstocks.  Most methanol in the world and all of the methanol used in California as a vehicle fuel is made from natural gas.  The conversion process typically used, called steam reforming, is similar to the process used to make synthetic diesel, but uses different catalysts, temperatures, and pressures.  The upstream fuel cycle is similar to compressed natural gas.  Fuel distribution for methanol consists of bulk storage terminals and

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