Since the early 1990s, BASF has been a technology leader in the
effort to curb nitrous oxide (N2O – commonly known as laughing
gas), a significant contributor to greenhouse gas.
Using its proprietary catalyst, BASF has managed to save, at its
own sites around the world and at customers’ sites too, nitrous
oxide emissions that are equivalent, to about 20 million tons of
carbon dioxide per year since 1998. As of 2008, this figure will
increase to around 40 million tons annually.
In the early 1990s, BASF developed the first catalyst for
removing nitrous oxide from the waste gas emitted by adipic acid
and nitric acid plants, and started using it on an industrial scale
in 1997. This patented process catalytically converts N2O emissions
into nitrogen and oxygen, both components of the air we breathe. In
adipic acid plants, the heat released by the decomposition of
nitrous oxide can also serve to generate process steam, enhancing
the energy efficiency of the process.
Using this process enabled BASF to make a voluntary commitment
to the German authorities in 1997 to reduce nitrous oxide emissions
in the production of adipic acid by 90 percent. In 2008, BASF’s
customers started using this process as well.
To reduce laughing gas emissions from nitric acid plants, BASF
resorts to a so-called secondary process in which the catalyst that
breaks down nitrous oxide is mounted below the noble metal screens
in an existing ammonia oxidation reactor. In this way, the nitrous
oxide formed on the noble metal gauze in a side-reaction is
immediately decomposed again. The use of different catalyst types
and geometries allows the technology to be adapted to specific
plant requirements and operator demands. This ensures optimum plant
operation and the best possible reduction of nitrous oxide.
Operators do not need to invest either in a separate reactor or
further supplies such as energy or additives, thus making the
life-cycle cost of the process particularly advantageous.
BASF is the only N2O decomposition technology supplier with
10-years commercial scale experience, as well as the only one
producing nitric acid and using the technology in its own
installations. With this extensive experience, BASF continues
to improve these highly efficient, durable catalysts.