234
Alternative Fuels for Transportation
Compressor
Dryer
Filter
Dispenser
Storage cylinder
Figure 8.2
Schematic of refueling system.
In the mother-daughter concept, the mother station is a compressor station,
which caters compressed gas. The CNG thus produced is transported to various refueling stations with the help of light commercial vehicles mounted
with a cascade of cylinders. The refueling stations where retail dispensing of
CNG takes place are called daughter stations.
In the on-line station concept, the CNG is tapped from the gas pipeline
and is stored and distributed in the same way. The transportation through a
pipeline reduces the cost of transportation of CNG, but it depends upon the
linkage of stations connected through the pipeline network.
8.5 CNG Safety
Compressed natural gas has some excellent physical, chemical, and combustion characteristics that make it a safe engine fuel. The safety aspects of CNG
fueled engine operations are generally superior to those of engines fueled
with conventional fuels such as gasoline or other alternative fuels. Natural
gas or methane is a nontoxic gas that is lighter than air. This means that it
will not puddle (like gasoline) or sink to the ground like propane, which is
heavier than air. Instead, NG will rise and dissipate in the atmosphere. Karim
and Wierzba (1992) reviewed the safety measures associated with operation
of engines with various alternative fuels. Based on the observations made by
them, the following is summarized.
Natural gas is compressed and stored in metallic cylinders. The safety of
the cylinders depends upon its strength and the conductive nature of metallic cylinders. This is unlike the relatively fragile conventional liquid fuel
Alternative Fuels for Transportation
Compressor
Dryer
Filter
Dispenser
Storage cylinder
Figure 8.2
Schematic of refueling system.
In the mother-daughter concept, the mother station is a compressor station,
which caters compressed gas. The CNG thus produced is transported to various refueling stations with the help of light commercial vehicles mounted
with a cascade of cylinders. The refueling stations where retail dispensing of
CNG takes place are called daughter stations.
In the on-line station concept, the CNG is tapped from the gas pipeline
and is stored and distributed in the same way. The transportation through a
pipeline reduces the cost of transportation of CNG, but it depends upon the
linkage of stations connected through the pipeline network.
8.5 CNG Safety
Compressed natural gas has some excellent physical, chemical, and combustion characteristics that make it a safe engine fuel. The safety aspects of CNG
fueled engine operations are generally superior to those of engines fueled
with conventional fuels such as gasoline or other alternative fuels. Natural
gas or methane is a nontoxic gas that is lighter than air. This means that it
will not puddle (like gasoline) or sink to the ground like propane, which is
heavier than air. Instead, NG will rise and dissipate in the atmosphere. Karim
and Wierzba (1992) reviewed the safety measures associated with operation
of engines with various alternative fuels. Based on the observations made by
them, the following is summarized.
Natural gas is compressed and stored in metallic cylinders. The safety of
the cylinders depends upon its strength and the conductive nature of metallic cylinders. This is unlike the relatively fragile conventional liquid fuel