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Route to cleaner shipping |
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Wednesday, 15 April 2009 |
 WHEN it comes to greenhouse gas emissions, the shipping industry is neither lean nor green. Ships carry about 90% of global trade and, until recently, such has been the demand for coal, cars and electronics that there has been little concerted effort to rein in the growth of polluting emissions from ships.
But pressure is growing in the United Nations and from the European
Union to make ships more efficient and their smokestacks more
climate-friendly.
Just a few kilometres from one of the busiest ports in the world, a
Singapore firm says it has the answer that can help the shipping
industry clean up its act. Ecospec says it has invented and tested a
patented method that removes planet-warming carbon dioxide (CO2) and
nitrogen oxides; sulphur dioxide, which causes acid rain; and soot from
ship exhausts.
The process, which uses very alkaline sea water sprayed into the
exhaust funnel to scrub out the gases and soot, has already been tested
on a tanker and earned the backing of the American Bureau of Shipping.
Inventor Chew Hwee Hong said his firm had already developed
non-chemical methods of water treatment and in 2008 was given a
challenge by a large Middle-Eastern tanker firm to find a way to scrub
out CO2 emissions. The trick was to find a method that didn’t cause
secondary environmental damage and cleaned up the other polluting gases
in the exhaust as well, he said.
Shipping contributes about 4% of global emissions from burning fossil
fuels, about double the emissions from aviation. But the industry is
less visible to most people than aviation and only very recently faced
limits on some of the pollutants in funnel emissions, particularly
nitrogen oxides (called NOx) and sulphur dioxide.
Nitrous oxide (N2O) and nitrogen dioxide (NO2) are powerful greenhouse
gases. Many new ships have engines designed to emit much lower amounts
of these gases, but thousands of older vessels do not, at least not
without costly retro-fitting.
An internal report submitted to the Marine Environment Protection
Committee of the International Maritime Organisation (IMO) in 2007
estimated total CO2 emissions from shipping at 1.12 billion tonnes in
2007 and forecast 30% growth by 2020.
The committee is due to meet again in July and is expected to present a
scheme to curb CO2 emissions from global shipping, although it’s
unclear if it will be adopted by the IMO in time to be included in a
broader climate pact by December. The pact is expected to be finalised
in the Danish capital Copenhagen in December when some 190 nations will
try to agree on an expanded deal to replace the Kyoto Protocol, the
United Nations’ (UN) main weapon to fight climate change.
The European Union will include aviation in its emissions trading
scheme from 2012 and has threatened to include shipping from 2013
unless there is a UN-backed international pact to regulate maritime air
pollution by the end of 2011. While aviation is easier to regulate and
monitor, shipping is much tougher. It’s unclear if the flag state,
owner or operator are responsible for the greenhouse gas pollution and
which agency would assess current emissions or allocate allowances.
Chew said individual methods exist to scrub out CO2, sulphur dioxide
and NOx, but he says his method is the only one to date that can tackle
all three, plus clean up the soot. Tests have shown the process, called
CSNOX, can remove about 90% of sulphur dioxide, 80% of NOx and nearly
7% of CO2, he said.
“We don’t want to use chemicals in CSNOX,” Chew explained. “We wanted
to use a pure physical method to do it so you don’t cause secondary
pollution.”
The secret of CSNOX is pure chemistry, says Chew, the firm’s managing
director and a marine engineer by training who nearly failed chemistry
in high school. The process uses electrolysis and ultra-low frequency
waves to raise the alkalinity of sea water to a pH of 10 from a normal
level of 8.1. Kitchen bleach has a pH of about 13, while battery acid
is at the other end of the scale at about 0.
Sea water is pumped into a tank, the alkalinity is quickly raised and
then the water is sprayed into the exhaust funnel where the dirty water
is collected, filtered and pumped into an aft tank for further
processing. It would cost between US$500,000 and US$1mil (RM1.85mil to
RM3.7mil) to fit the system to most ships.
Chew said the water that is pumped back into the sea is more alkaline
than normal and contains sulphates, nitrates and carbonates that sea
life need. This is a beneficial byproduct because the world’s oceans
are becoming more acidic as global atmospheric levels of CO2 rise from
burning fossil fuels.
Oceans are a major carbon sink, soaking up large amounts of CO2 in a
process that creates carbonic acid. Recent Australian research has
shown that rising acidity has trimmed the shell weights of tiny marine
animals.
Existing methods to remove sulphur dioxide from ship exhausts release
CO2, Chew explained. A Canadian study found that removing sulphur
dioxide from ship exhausts actually contributed to global warming.
“If you scrub out 1kg of sulphur dioxide, you produce 2.75 kg of CO2,”
he said. But by using highly alkaline seawater, the CSNOX process
avoids this side-effect because it neutralises the sulphur dioxide.
Ecospec, which first announced details of the CSNOX process in January,
has since received nearly 60 enquiries, among them from major shipping
lines and oil companies.
“The trend is just irreversible. You have to go this way. You can’t be
a ship-builder without knowing how to install or how to design
(emissions-control technology),” Chew said.
He said the company was now looking to adapt the process to clean up
emissions from power stations, steel and cement makers and
pulp-and-paper mills, as well as rubbish incinerators.
Source: Reuters
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