Industrial flue gas treatment system is a set of technologies which is used to remove hazardous gases such as sulphur dioxide (SO2) and nitrogen oxide (NOx) from the emission of industries and power plants. Fossil fuels such as oil and coal contain specified amount of sulphur. When these fuels are combusted in the presence of air almost 95% or more sulphur is directly converted into sulphur dioxide (SO2). When flue gas has excess quantity of oxygen it is again converted into sulphur tri oxide (SO3). In flue gas treatment system the flue gas is generally passed through an ash removal device and then through a SO2 absorber.
Air pollution is treated as the most serious problem now a day. The increase in the number of industries and power plants lead to emission of sulphur dioxide and other gases in atmosphere. This sulphur dioxide directly reacts with vapors and other compounds in atmosphere to form acid rain and fog. The increasing concern about the atmosphere is the major driver for the market of flue gas treatment system. Reduction in the operating cost by the means of heat recovery, reduction in stack plume, improvement in operability of industries, are drawing social attention towards this market. Cost associated with the installation of gas treatment system and maintenance restricts the market somewhere. Strict policies regarding pollution control, advancement in technology and various incentive benefits provided by appropriate commissions for reducing emission bring new opportunities to the market.
Flue gas treatment systems are segmented on the basis of gases types that are required to be removed from the emission. For removal of NOX the flue gas is passed through a mixture of active catalyst. This converts nitrogen oxide (NOx) into naturally occurring nitrogen and water. Most of the FGD units are based on two levels, one for fly ash elimination and other for sulphur dioxide reduction. In wet scrubber system the flue gas usually passes all the way through a fly ash elimination device, either through an electrostatic precipitator or a wet scrubber then to a sulphur absorber. Various types of wet scrubber designs are used such as plate towers, venturi and mobile packet beds.
A venturi scrubber is a converging duct and this duct accelerates the velocity of the gas stream. When a liquid stream is injected, at the point of maximum velocity turbulence caused by higher velocity atomizes the liquid into small droplets thus creating a surface area for mass transfer. In packet bed scrubber a packing material is placed inside a tower. The packing material can be in the shape of rings or some specialized shapes designed to maximize the contact area for liquid and gas. For a specific collection area electrostatic precipitators are also used. Flue gas enters from the inlet of a chamber containing two charged electrodes and the suspended particles get attracted to the opposite polarized electrodes.
The clean gas leaves the chamber from the outlet. Mercury emission from the flue gas is a significant environmental concern because of toxicity and high volatility. Carbon fibers beds are usually used to remove heavy metals like mercury and organic pollutants from the flue gas. The flue gas flows parallel through the filter bed while the absorbent flows from top to bottom. The industrial flue gas treatment systems are widely used in industries such as power generation, cement manufacturing, metal and chemical processing.
Maximum number of power plants and manufacturing industries in North American region makes the region best suited for the market. In Asia Pacific region India and China are continually making new investments in the production industries making the region a great option for the investors. European countries such as Sweden, Germany and Switzerland have decided to shift over renewable providing fewer opportunities for the market.
Some of the key players in the flue gas treatment systems are Non-Tel Systems, STT Environ Corp, Beltran Technologies, Envitech, Agilis Technology, Classifier Milling Systems, Chattanooga Boiler & Tank Co. and Ducon Environment System among others.