Page 105 - Oil and Gas Production Handbook An Introduction to Oil and Gas Production

cars and ships, which account for about 45% of emissions from hydrocarbon
fuels, not replaceable by other known energy sources at this time.
There are three main problem areas:
• There are losses in production: only about 70% of hydrocarbons
extracted from the ground reach the private or industrial consumer.
The rest is lost from production systems, transportation and through
the refining and distribution of oil and gas.
• There are losses in consumption: much of the oil and gas is
converted to work with an efficiency of 30% in cars for example to
60% in the best power plants.
• Better methods for capturing and storing emissions must also be
found.

Efficiency will be improved by maintaining and operating facilities to reduce
losses, and by converting to more efficient systems. As an example, it can
be argued that conversion to electrically-driven equipment in place of gas
turbine-driven equipment could reduce CO 2 emissions by more than 50%
even if power is generated by a gas turbine and steam combined cycle unit.
This also moves the emissions to a centralized unit rather than distributed to
a larger number of smaller gas turbines.

To reduce overall emissions, carbon will have to be separated from other
emitted gases (such as water vapor) and disposed of. Current plans call for
re-injection into empty reservoirs, or reservoirs that need pressure
assistance for oil extraction.

Capturing CO2 can be used at large point sites, such as large fossil fuel or
biomass energy facilities, industries with major CO 2 emissions, natural gas
processing, synthetic fuel plants and fossil fuel-based hydrogen production
plants:

Overall there are three types of processes:

• Pre-combustion systems, where the fuel is gasified and processed
before combustion and carbon dioxide can be removed from a
relatively pure exhaust stream.
• Post-combustion systems where carbon dioxide is extracted from
the flue gas, e.g. using an amine process.
• Oxyfuel consumption, where fuel is burnt as relatively pure oxygen,
so the hydrocarbon is burned in oxygen instead of air. This produces

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