NEWS RELEASE FEBRUARY 2016
Innovations Changing the Industrial Scrubber Industry
End users and suppliers are both challenged to keep up with the rapid developments in particulate scrubbing, gas absorption, gas adsorption, dry scrubbing, condensation separation and biofiltration in industrial processes such as iron and steel, cement, waste-to-energy, natural gas treatment and sewage sludge incineration (scrubbers in coal-fired power are analyzed separately).
The drivers behind this rapid pace are regulations and innovations. The regulations in one country soon are copied in others. The innovations in one industry are eventually embraced by other industries but not as quickly as they should be. It is highly desirable to continually determine how the successes in one application can be applied to others.
Foundry cupolas, BOF furnaces, and waste-to-energy plants can no longer rely on particulate scrubbers to meet the stringent emission standards. Instead fabric filters are the leading choice. This has led to the development of dry scrubbers which can be used in combination with fabric filters. So the dry scrubber segment has grown robustly while the particulate scrubber segment has stagnated.
However, even newer regulations identifying condensibles as a component of total particulate has opened the door to the wet approach. Regulations addressing liquid and solid waste have favored dry scrubbing. However, some new wet approaches resulting in usable byproducts have caused growth in the wet scrubbing segment.
Condensation scrubbing is a growing segment thanks to the concern with greenhouse gases and the potential for extracting heat from exhaust gases.
The air pollution control systems in waste-to-energy plants in Europe incorporate a number of innovations. Four stages of scrubbing result in hydrochloric acid, gypsum, precious metals, salable ash and capture of the exhaust gas heat.
The development of highly reactive lime particles coupled with catalytic filters allow acid gas, NOx and particulate removal at 850°F. The heat from the clean gas is then easily extracted. Glass furnaces, biomass combustors and other sources have embraced this technology.
There are innovative ways to remove mercury. The non-ferrous smelting industry is using unique chemistry in wet absorbers. A number of sewage sludge incinerator operators in the U.S. have incorporated mercury adsorber modules into their scrubbers. The modules can handle the wet gas leaving the mist eliminators.
Membrane contactors are proving to be an improvement for separating gases such as CO2 and H2S.
The cutting edge technology is ionic liquids being used in mercury removal from natural gas. This promises to have wider application for pollutant removal in many combustion sources.
A gas bubble encapsulation technology is still in the pilot stage but the conversion of the gas stream into bubbles one-thirtieth of one inch in diameter creates mass transfer surfaces thousands of times greater than packed towers on plate columns. The problem is the physical separation of the gas and liquid components after the absorption takes place. The company which solves this problem will change not only pollution control but many chemical processes.
The venturi scrubber which has been rejected for particulate scrubbing, may find a revival as a critical component of rare earth recovery from flyash. It can capture both HCl and particulate and start the leaching process of the rare earths all in one step. Additional particulate removal then takes place in wet precipitators.
McIlvaine is conducting cross pollination webinars. Decision guides in a number of industries are displayed and discussions regarding wider use of innovations encouraged. These discussions are free to everyone. The decision guides are included in the following two services: