Over the past several decades there have been immense improvements in process chemistry, a better understanding of materials, simplified designs, and other technological enhancements. Flue-gas desulfurization (FGD) is a set of technologies used to remove sulfur dioxide (SO₂) from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur dioxide emitting processes. SO₂ is now being removed from flue gases by a variety of methods:
- Wet scrubbing
- Spray-dry scrubbing
- Wet sulfuric acid process recovering sulfur in the form of commercial quality sulfuric acid
- Wet SNOX Flue gas desulfurization
- Dry sorbent injection systems
Scrubbers are a highly efficient and reliable means of removing SO₂ as well as particulate matter, hydrochloric acid, and other air toxins. Scrubbers have been already used for 25 years, but some people may be unaware of the improvements that 25 years of continuous refinements have brought. In just the past few years numerous technical enhancements to scrubbers have occurred in such areas as reliability, cost, waste prevention, and energy consumption. The fact is the air pollution control business is highly competitive, so it is aggressive and cost-conscious. In addition, research and development, demonstration and full-scale testing are ongoing.
There is a common prejudice that scrubbers are unreliable. In point of fact, early scrubber systems did have problems and some were fairly unreliable. However, recent experience at individual utilities confirms that wet scrubbers now are very reliable, with availability over 99 percent in many cases, and often close to 100 percent. In addition to this, there is an opinion that scrubbers do not achieve high enough SO₂ removal efficiency, but actually, scrubbers are very efficient air pollution control devices and can remove greater than 95 percent of the SO₂ from power plant stack emissions. In fact, SO₂ removal efficiencies often are as high as 98 percent to 99 percent.
Furthermore, wet scrubbers are capable of removing significant quantities of particulate matter and chlorine gas. Independent industry experts have concluded that retrofitted SO₂ scrubbers can remove a high percentage of particulate matter from flue gases and nearly all the hydrochloric acid (HCl) from stack emissions.
Additionally, there is an entrenched misconception that scrubber systems cost too much. Nowadays, however, technological advances, increased experience, and flexible regulations have contributed to significant declines in the capital and operating costs of scrubbers relative to historic values. Furthermore, modern financing schemes have been devised which reduce or eliminate the capital costs borne by the utility.
Wet scrubbers are an effective air pollution control devices. To effectively work, many variables are considered when designing. Most commonly, a wet scrubber consists of a vessel, ductwork, fan, mist eliminator, pumps, and the liquid treatment.
Being a new type of wet air scrubber, multi-vortex wet air scrubber provides improved air treatment quality and can be used for both particles matter and gas collection. The treatment quality of multi-vortex wet air scrubber is generally 99.95-99.99% for both types of pollutants. Besides high efficiency, multi-vortex wet air scrubber possesses a number of advantages over conventional wet scrubbers – multi-vortex wet air scrubber is compact, omnivorous, eco-friendly, economical, and low-maintenance.