Emission control for process industries

Emission control is a milestone in global environmental protection for humans, animals and the earth itself.

GEA sets standards for the process industry, offering state-of-the-art, cost-effective and high-performance gas cleaning technologies to reduce allowable concentrations of pollutants like: 

  • Particulate matter
  • Sulfur oxides (SOx)
  • Nitrogen oxides (NOx)
  • Ammonia (NH3)
  • Halogens (F2, Cl2, Br2, I2)
  • Hydrogen halides (HF, HCl, HBr, HI)
  • Heavy metals (lead, mercury)
  • Volatile organic compounds and odor
  • Other organic hazardous air pollutants

These pollutants are found all over the industrialized world and can harm health and environment, and cause property damage. A unique combination of technology leadership, process insight and global presence enables us to deliver world-class systems in accordance with quality, reliability and financing opportunities to minimize the air pollution impact. 

We supply tailor-made, integrated solutions, based on the expertise from many years of experience in development, design and installation of emission reduction systems:

Dedusting (removal of particulate matter)

Dedusting is an emission control technology to ensure the precipitation of particles and aerosols prior to venting to the atmosphere.

The main air pollution control devices used are: 

  • Scrubbers
    • Scrubbers are used for dust removal in saturated waste gases. In these systems, the scrubbing liquid comes into contact with an exhaust gas stream containing dust particles. Efficiency is depending on contact time of the gas and liquid streams. 
    • GEA has developed special wet scrubbers like Venturi scrubber, jet type scrubber, annular gap scrubber and submerged scrubber to meet customers’ specific demands. Adjustable scrubbers are high-efficiency units, which have been developed by GEA especially for the conditions in the industrial process industry.
  • Electrostatic Precipitators
    • Electrostatic precipitators use electrostatic forces to separate dust particles from exhaust gases. While the contaminated gases flow through the ionized field between the electrodes the particles receive a negative charge as they pass through and then these charged particles are attracted to a grounded or positively charged electrode and adhere to it.
    • All GEA electrostatic precipitators (ESP) are operating with high efficiencies and can achieve very low particulate loads in emitted exhaust gas. GEA is using either dry-type electrostatic (ESP) precipitators or wet electrostatic precipitators (WESP) depending on the application 
  • Filters
    • Baghouse filters or Candle filters are based upon filtration by the use of textile or ceramic materials and are the technology of choice in many cases when a low dust content has to be achieved. Their ability to remove large particulate loads on a non-selective basis has made them important for many applications.
    • GEA´s unique low-pressure pulse-jet filter technology ECOpuls is especially applicable for treatment of large gas flows. 
  • Cyclones
    • Cyclones are often used for pre-dedusting of waste gases with high dust load.
  • Column scrubbers
    • Column scrubbers are utilized as primary stage of a wet gas cleaning system for special applications, i.e. hot and corrosive gases with high dust, arsenic or selenium loads, which occur in some metallurgical processes.

Flue Gas Desulfurization (FGD, removal of sulfur oxides)

Flue Gas Desulfurization involves the removal of sulfur dioxide (SO2) contained in gases produced by the combustion of fossil fuels or of industrial processes such as cement, glass, steel, iron, and copper production. 

The cleaning required is often not only to absorb acid components such as SO2, HCL, HF, etc by means of injection of hydrated lime [Ca(OH)2] or sodium bicarbonate [NaHCO2] but also to collect particulates to fulfill dust emission requirements, and further to absorb dioxins (PCDDF) and heavy metals by activated carbon if needed.

There are various SOx Control processes available. In the Dry DeSOx and Semi Dry DeSOx Process powdered hydrated lime (or other sorbent material) is injected into exhaust ducts to eliminate SO2 and SO3 from process emissions. The Wet DeSOx Process uses a slurry of alkaline sorbent, usually limestone or lime, or seawater to absorb the sulfur component and to scrub gases. 

The main sulfur oxides emission control devices used are:

  • Scrubbers
    • Scrubbers are used for dust removal in saturated waste gases. GEA has developed special scrubbers for different applications like Venturi scrubber, annular gap scrubber, and submerged scrubber.
  • Filters
    • Baghouse filters/Candle filters are the technology of choice in many cases when low dust content is needed for gas cleaning. Their ability to remove large Loads on a non-selective basis has made them important for many applications.
    • GEA´s unique low pressure technology ECOpuls is especially applicable for treatment of large gas flows.
  • Spray drying absorption (SDA)
    • GEA gas cleaning technology is an economical and environmental-friendly solution for tackling existing and upcoming regulations and is tailor-made to provide flexibility and reliable operations wherever our customers operate. The absorbers boast well-proven system features such as peak-control and activated-carbon injection which have been designed for the purposes of ensuring low mercury and dioxin emission.

NOx Control Technology (removal of nitrogen oxides)

An effective method for controlling nitrogen oxide emissions (NOx) from combustion sources is Selective Catalytic Reduction (SCR) technology.

The technology is based on the chemical reduction of nitrogen oxides (NOx) into molecular nitrogen (N2) and water vapor (H2O). The SCR technology utilizes a catalyst to increase the NOx removal efficiency, which allows the process to occur at lower temperatures. Depending of the location of the DeNOx unit (i.e. upstream or downstream of the dedusting stage) a difference is made between high-dust and low-dust applications. 

The main nitrogen oxides emission control device used is:

  • Selective Catalytic Reduction (SCR) Reactor
    • The NOx reduction reaction takes place as the gases pass through the catalyst chamber. Before entering the catalyst chamber ammonia or other reductant (such as urea), is injected and mixed with the gases. GEA SCR technology achieves high NOx reduction rates with limited ammonia slip and allows a simultaneously oxidation of further pollutants like dioxin, furan, organics and mercury.

Absorption (removal of acid pollutants)

Absorbers facilitate the removal of acidic gas pollutants like halogens (F2, Cl2, Br2, I2), hydrogen halides (HF, HCl, HBr, HI) and low molecular weight alcohols, carboxylic acids and amines from off gases.

The main emission control devices for absorption used are:

  • Scrubbers
    • Scrubbers are not only used for dust removal in saturated waste gases but also to absorb acid components. GEA has developed special scrubbers for different applications like Radial Flow scrubber, Venturi scrubber, jet type scrubber, annular gap scrubber, and the submerged scrubber.
    • Furthermore, small emergency scrubber units are often installed as safety devices during storage, in dosing stations, for the transportation of halogen, halogen-hydrogen and ammonia.
  • Spray drying absorption (SDA)
    • Spray Drying Absorption - the unique use of the spray drying technology for acid-gas absorption - was originally invented by GEA in the 1970s. Ever since, it has been subject to continuous further development and optimized to meet changing conditions and requirements. Hence, the process stands as an efficient, versatile and thoroughly tested technology. 
  • Electrostatic Precipitator Absorber (EP Absorber)
    • This specially designed electrostatic precipitator with absorber section is mainly used for the Fluid Catalytic Cracking (FCC) Gas cleaning Process. 
  • Absorption Columns
    • Through special motive nozzles, a scrubber medium is injected and distributed at the top of the column to produce a maximum gas/liquid exchange area, and at the same time, the quenching effect leads to the cooling of the gases or vapors. 

Heavy Metal Removal

The Calomel Process for Mercury Removal is based on the oxidation of mercury vapor by mercuric chloride to form mercurous chloride (calomel) which can be separated by scrubbing.

VOC & Odor Removal

Volatile organic compounds (VOCs) and Odor are often simultaneously co-treated in other gas cleaning processes like scrubbing or catalytic reactions.

Dioxin/Furan Abatement 

Dioxin and Furans are known as one of the most toxic groups of organic substances and are often simultaneously co-treated in other gas cleaning processes by adding an adsorbent (activated carbon, hearth furnace coke, or zeolites) or catalytic reactions.

Gas cooling & conditioning

GEA gas cooling system introduce a controlled amount of finely atomized water into the hot gas stream in order to reduce and/or maintain gas temperature. The water evaporates to complete dryness, while absorbing heat from the gases, for free-flowing dust, zero liquid discharge, and minimal or no wall buildup.

The main emission control devices for gas cooling and conditioning used are:

  • Quench Tower, Hot Gas Quench or Evaporation Cooler
    • The Quench system is cooling high temperature exhaust gases from an incinerator, melting furnace, drying furnace, or any other hot gas flow and is often used as a pre-cooler for scrubbers, or electrostatic precipitators, etc. 

Waste Heat (Energy) Recovery 

Saving of energy cost and reducing CO2 emission makes an energy recovery plant an investment not only providing competitive advantages on final product cost, but also helping to preserve our environment for our future generations. Waste heat within a process can be recovered by using the Organic Rankine Cycle (ORC) Process or by increasing the economic efficiency by implementing energy heat exchange units in the industrial process.

  • Waste heat recovery unit (WHRU)
    • The Waste Heat Recovery Units are gas/thermal oil heat exchangers providing highly efficient heat transfer. Designed individually for each application, GEA units can accommodate different gas/dust concentrations and temperature ranges.
    • Each WHRU is equipped with a suitable cleaning system specifically designed for the expected working conditions of the unit such as high dust load or sticky dust.