Canadian
researchers have found a new way to reduce energy
consumption and emissions often released by the
oil and gas industry.
When natural gas emerges from
gas wells, it is saturated with water. This water
can cause corrosion that can lead to pipeline
leaks or cause formation of hydrate plugs (ice-like
solids composed of water and natural gas) that
shut off the flow of gas. Gas companies remove
the water using glycol dehydrators.
Water from the gas is absorbed
in the glycol (an organic chemical often used
as antifreeze.) The glycol is then heated, a process
known as reboiling, separating the glycol from
the water. The water is released into the atmosphere
as steam, while the glycol is saved for reuse.
This process requires a lot of energy as its key
ingredient and often emits harmful compounds,
like benzene (a carcinogen), into the atmosphere.
Canadian Environmental Technology Advancement
Centres (CETACs) are independent, non-government
organizations, helping small and medium-sized
enterprises commercialize leading-edge environmental
technologies and lessen their environmental impact.
CETAC-WEST, located in Calgary,
Alberta, saw an opportunity to reduce energy consumption
in glycol dehydrators and contacted RCL Environment
Group Ltd. and Amine Experts to develop an easy-to-use
process optimization model. The creation of such
a model would allow oil and gas field operations
to calculate fuel savings and emission reduction
available without needing costly computer models.
Rod Leland, Managing Director
of RCL, estimates that total annual fuel savings
of $50 million and CO2E (carbon dioxide equivalent)
reductions of over 350 000 tonnes can be achieved
by optimizing Canada's glycol dehydrators.
Glycol dehydrators are initially
setup at optimal rates. However, over time, gas
production rates and pressures can fluctuate as
wells decline and new wells are brought on stream.
Over 3000 glycol dehydrators
operate in Canada, providing dramatic opportunities
for energy consumption and emission reductions.
By reducing glycol circulation rates, less demand
is placed on the related reboiler burners. Optimization
of glycol dehydrators can reduce energy by as
much as 25 per cent and simultaneously reduce
benzene emissions without additional capital expenditure.
"This is a classic example
of how doing what's right is good for the economy
and the environment," says Mr. Leland.
The model developed with CETAC's
support is gaining rapid acceptance in the upstream
oil and gas industry. A number of operating companies
are posting copies on individual dehydrators to
assist operators in maintaining optimum operating
conditions.
The oil and gas industry's use
of this optimization model could also be seen
as favourable by regulatory agencies. Benzene
is identified in the Canadian Environmental Protection
Act as a toxic substance. This enables Environment
Canada to take steps, including the potential
of developing regulations, to control benzene
emissions. The oil and gas industry has agreed
first to a voluntary approach, committing to reduce
and report benzene emissions to environmental
authorities. The optimization of glycol dehydrators
is a good example of voluntary reduction of emissions.
Environment Canada has a leadership
role in making sustainable development a reality
in Canada. An important priority in this regard
is the advancement of innovative technologies
that address Canada's environmental challenges.
As one of its means to address
this priority, Environment Canada has supported
the CETACs since 1994, in a partnership that has
helped over 2000 small- and medium-sized Canadian
enterprises advance the development and use of
innovative environmental technologies.
