194
Alternative Fuels for Transportation
NO x concentrations were obtained, but due to the coal, there were still particulate emissions, which were reduced through the use of DME (JDF 2007).
There is a substantial potential for the use of DME in the power generation and industrial sectors. With respect to implementation of a new alternative fuel, this offers a substantial advantage in that the installations can be
large, and use significant amounts of fuel at few locations. In contrast to a
vehicular application, where there are many consumers, and consumption
is spread over a wide geographical area, there are fewer users operating at
fixed geographic locations. Thus supply infrastructure is much simpler than
for vehicle applications, and with fewer users, it should be simpler to negotiate agreements related to the supply of DME.
6.4.3 Domestic Applications
Since its physical properties are quite similar to those of LPG, it is also to be
expected that DME can be used for domestic purposes, such as cooking and
domestic heating. This is indeed the case, and in fact, the first commercial
use of DME as a fuel has taken place in China for this purpose. Here, excess
methanol capacity has been converted to the manufacture of DME by dehydration. The methanol is obtained by coal gasification.
Pure DME burns well in domestic applications (JDF 2007; Sanfilippo 2004).
When converting from LPG burners to DME burners, two major considerations must be taken into account. The first is that the stoichiometric air–fuel
ratio for DME is 9.0:1 as opposed to about 15.5 for LPG. In order to maintain
the same excess air ratio, the fuel nozzle area must be increased when converted to DME. The second consideration is that seals and hoses and other
components with plastics and elastomers must be checked for compatibility
with DME and changed as needed.
An additional use of DME is as an extender to LPG. Studies have shown
that LPG with a DME addition of up to about 20%, can be used without modification in existing LPG equipment (Sanfilippo et al. 2004). When DME is
blended into LPG in moderate amounts, studies have shown the material
compatibility is not a significant issue. Use of DME as an extender for LPG
appears to be a very attractive application for the initial introduction of DME
into the market place. There is a large established market, and the DME can
be commercially introduced into the market place with very little change
in product and infrastructure. This is important, in that a large production
serves to verify the credibility of the manufacturing processes, and provides
the first real economic basis to evaluate the fuel in practice. The “chicken and
egg” situation is known for many fuel alternatives.
6.4.4 Fuel Cells
A final application to be mentioned is that of fuel cells. It has been shown that
pure DME can be used to obtain power from a fuel cell (JDF 2007; Kajitani
Alternative Fuels for Transportation
NO x concentrations were obtained, but due to the coal, there were still particulate emissions, which were reduced through the use of DME (JDF 2007).
There is a substantial potential for the use of DME in the power generation and industrial sectors. With respect to implementation of a new alternative fuel, this offers a substantial advantage in that the installations can be
large, and use significant amounts of fuel at few locations. In contrast to a
vehicular application, where there are many consumers, and consumption
is spread over a wide geographical area, there are fewer users operating at
fixed geographic locations. Thus supply infrastructure is much simpler than
for vehicle applications, and with fewer users, it should be simpler to negotiate agreements related to the supply of DME.
6.4.3 Domestic Applications
Since its physical properties are quite similar to those of LPG, it is also to be
expected that DME can be used for domestic purposes, such as cooking and
domestic heating. This is indeed the case, and in fact, the first commercial
use of DME as a fuel has taken place in China for this purpose. Here, excess
methanol capacity has been converted to the manufacture of DME by dehydration. The methanol is obtained by coal gasification.
Pure DME burns well in domestic applications (JDF 2007; Sanfilippo 2004).
When converting from LPG burners to DME burners, two major considerations must be taken into account. The first is that the stoichiometric air–fuel
ratio for DME is 9.0:1 as opposed to about 15.5 for LPG. In order to maintain
the same excess air ratio, the fuel nozzle area must be increased when converted to DME. The second consideration is that seals and hoses and other
components with plastics and elastomers must be checked for compatibility
with DME and changed as needed.
An additional use of DME is as an extender to LPG. Studies have shown
that LPG with a DME addition of up to about 20%, can be used without modification in existing LPG equipment (Sanfilippo et al. 2004). When DME is
blended into LPG in moderate amounts, studies have shown the material
compatibility is not a significant issue. Use of DME as an extender for LPG
appears to be a very attractive application for the initial introduction of DME
into the market place. There is a large established market, and the DME can
be commercially introduced into the market place with very little change
in product and infrastructure. This is important, in that a large production
serves to verify the credibility of the manufacturing processes, and provides
the first real economic basis to evaluate the fuel in practice. The “chicken and
egg” situation is known for many fuel alternatives.
6.4.4 Fuel Cells
A final application to be mentioned is that of fuel cells. It has been shown that
pure DME can be used to obtain power from a fuel cell (JDF 2007; Kajitani