Hi I'm Susie. - Hi I'm Gavin. - Hi I'm Kieran.
- Hi I'm David. Johnson Matthey is a global company manufacturing a wide range
of specialty chemical products
These include cataylsts, which control pollution from vehicles.
These are fitted to cars and reduce emissions from the exhaust pipe,
ensuring that the air around us is clean and safe to breath. Today air
quality is very good
but fifty years ago that wasn't the case. The reason that it's good today
is thanks to the catalytic converters that we have fitted to our cars
and they control the harmful pollutants that otherwise would be emitted into the
atmosphere.
Governments around the world continue to set tighter and tighter emissions
limits
and introduce new regulations to control additional pollutants from different
types of vehicles.
Diesel cars are particularly popular in Europe
and account for about fifty percent of all the vehicle sales in that region.
Everyone has seen the black smoke or soot
coming out of the exhausts of diesel cars and evidence has shown that this soot
poses a serious hazard to our health
and to the environment. Legislation was introduced
to control the soot emissions from diesel cars alongside the other pollutants
of carbon monoxide, hydrocarbons and oxides of nitrogen
or NOx. Developing a new catalyst that can remove soot
from a car exhaust provided a lot of chemistry challenges for our scientists here at Johnson
Matthey.
It required innovative R&D and development of an environmentally responsible
manufacturing process.
The autocatalyst used in diesel cars is called a diesel
oxidation catalyst and effectively cuts emissions of hydrocarbons
and carbon monoxide by ninety percent. Unlike hydrocarbons and carbon monoxide
soot is made up of small, tiny particles of carbon. So our scientists had to come up with
a really clever technology
to deal with the soot emissions. We came up with the idea of the filter
which would trap the soot particles and stop them from leaving the exhaust tailpipe,
removing over 99 percent of the soot. The filter is visually different to a standard
autocatalyst.
With the standard autocatalyst you have channels running all the way through,
whereas with the filter alternate channels are blocked to make sure that the
incoming soot particles are trapped, but then there's a problem with the build up
of soot, as more and more soot is trapped. In order to help lower the build up of soot
we had to design a catalyst coating that could be applied to the filter.
This would then promote a reaction that would burn the trapped soot off as
CO2. After a lot of research we developed the right catalyst to
help burn of the soot. We call this a catalysed soot filter
and it is fitted into the car exhaust behind the diesel oxidation catalyst.
So, how does the catalysed soot filter work?
It's a filter coated with precious metal catalyst.
The catalyst promotes the reaction of nitrogen oxide,
which is present in small quantities in the exhaust,
to nitrogen dioxide (NO2)
and this NO2 reacts with the soot, converting it to carbon dioxide
(CO2). The catalyst also helps with the oxidation of carbon monoxide and hydrocarbons
too,
meaning that a small diesel oxidation catalyst can be used on the vehicle.
The CO2 from soot combustion and the gases produced from the diesel oxidation
catalyst pass through the filter walls
and then they leave the exhaust tail pipe.
Once we understood the chemistry we then had to test the product
in our test cells and on real vehicles to prove that it could meet the regulations,
could withstand extreme conditions within the car exhaust
and did not become deactivated over time by the impurities present in a diesel
fuel.
We have also developed a product that combines the DLC and CSF into one unit,
which is preferred by some car manufacturers.
However, the majority of diesel cars these days have the two unit
system of a diesel oxidation catalyst and a catalysed soot filter.
At the same time we started to develop a whole new manufacturing process
so we could make these catalysts at a large enough scale to meet the needs of
the European car market.
The process we use is very much different to the process we use for
developing autocatalysts for the petrol cars.
We've constructed 2 world scale production sites here in Royston in the
UK.
We've now sold over 1.5 million catalysed soot filters to european car
manufacturers,
which will prevent around 12 million kilos of soot being emitted into our
atmosphere
over the lifetime of these vehicles. This is good news
as it is estimated by the EU that particulate matter
may contribute to up to 20,000 premature deaths each year in Europe. Legislation
will continue to tighten around the world.
The next European legislation, due to come into effect in 2014,
will mean that the level of NOx emissions from vehicles will need to be reduced.
Here at Johnson Matthey we're already working on combining
the catalysed soot filter with nitrogen oxide emissions control
for the next generation of automotive emissions catalysts.
Since their introduction in 1974 our catalysts have removed around four billion tons of
pollutants from the atmosphere.
Chemists play a vital role in developing the very latest catalysts and
technologies
for emission control and on making sure we all have clean air.