Emission Control Catalysts

The importance of emission control catalysts has been increasing as environmental concerns and measures to fight pollution have become more important globally. Emission control catalysts are divided into two types according to the source of the emission—emission control catalysts for mobile sources (such as automobile catalysts) and for stationary sources (such as fossil fuel–fired power plants, diesel- and gas-fired engines, chemical and industrial processes, and marine and locomotive applications). The global catalyst market is expected to grow at around 10% annually (excluding platinum group metals) over the next five years.

The following pie chart shows world consumption of catalysts for mobile sources on a value basis:

The global distribution pattern is not expected to change greatly by 2015, but the market value is expected to increase by about 65%. The market for stationary sources is only about 7% of the value of the market for mobile sources.

Emission control catalysts for mobile sources are based on platinum group metals (PGMs) that convert vapor emissions into carbon dioxide, nitrogen and water. Despite much higher palladium prices during 2010, platinum still traded at more than twice the price of palladium, giving manufacturers an incentive to continue the substitution of platinum with palladium in their catalyst formulations.

The global emission control catalyst market (excluding PGMs) for mobile sources is forecast to grow at an average annual rate of almost 10.5% to 2015. The largest segment is the catalyst market for light-duty vehicles. Driving factors for growth include a further tightening of regulations since 2010 in the United States, the European Union and Japan, as well as the introduction of emission standards for heavy-duty diesel vehicles in China, India, Russia, the Republic of Korea and Brazil beginning in 2009/2010. Current catalyst consumption for the off-road market is still small; however, this market will grow at an average annual rate of about 47% to 2015 when stricter emission standards have been applied on a global basis.

The main processes used in stationary emission control catalysts are selective catalytic reduction (SCR), catalytic oxidation, catalyzed traps/filters for particulate matter and catalytic incineration of VOC emissions. The main end-use industries are fossil fuel–fired power plants, diesel- and gas-fired generators, turbines and boilers, chemical and industrial processes, and marine and locomotive applications.

Catalysts for environmental protection are becoming more widespread for applications such as off-gas cleaning, including

• NOx from electrical power plants, refineries and chemical plants, and furnaces, boilers and incinerators.
• VOC emission treatment from chemical plants, surface coating facilities, and so on.
• Regenerative thermal oxidizers and converters for exhaust streams in chemical plants.
• Dioxin reduction from waste incinerators.
• Catalytic converters in two-stroke stationary engines. Biofuels such as palm oil can be used in combined heat and power plants in a low-speed two-stroke engine. This combination represents a special challenge to NOx reduction technology to fulfill air emissions legislation. The chemistry of biofuels differs from fossil fuels in that the exhaust gas includes phosphorus, which needs to be taken into consideration in order to avoid catalyst deactivation. Two-stroke diesel engines, on the other hand, result in very low exhaust temperatures, demanding a particular design for reliable operation of NOx reduction.

Trends that are expected to affect the global emission control catalyst business from 2010 to 2015 include the following:

• Increasing automobile production, especially in developing countries.
• More-stringent legislation on automobile emissions in both developed and developing countries.
• More-stringent emission standards for off-road diesel engines (e.g., industrial drilling rigs, compressors, construction wheel loaders, bulldozers, nonroad trucks, highway excavators, forklift trucks, road maintenance equipment, snowplows, ground support equipment in airports, aerial lifts and mobile cranes, agricultural and forestry tractors) as well as for ships and vessels, and railway locomotives and railcars.
• More-stringent legislation on emissions from stationary sources.

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