thermal products engineering durban

Hot Gas Filtration

With increasing regulations world-wide on industries generating polluted gas and particulate matter, many companies face the challenge on how to reduce these emissions.

Macrotec’s Hot Gas Filters can be used for incineration, cremation, biomass boilers to mineral processing, for removing particulate to below 5 mg/m³, with Dry Gas Scrubbing removing acid gasses, dioxins, and heavy metals. Our filtration systems utilise ceramic filters for the highest removal efficiencies while also having the highest operating temperatures. Coupled with low maintenance and a modular design which ensures ultimate redundancy, Macrotec’s Filtration systems are hard to beat.

hot gass filtration

What is Hot Gas Filtration?

Multiple industrial processes produce emissions, containing products which are hazardous to people’s health, or pollute the environment. Most countries have instituted regulations that limit these emissions, requiring these gasses to be filtered.

Since these gasses often reach several hundred degrees, conventional bag-type filters will fail quickly due to the high temperatures, leaving Ceramic Filtration as the only long term reliable option.

Particulate Matter often consists of fine particles (PM 2.5), which are extremely harmful to people. PM 2.5 is unfortunately able to pass through many conventional filters, with Ceramic Filtration offering the only reliable method of capturing.

Dry Gas Scrubbers are used in conjunction with Ceramic Filters to either adsorb or neutralise other harmful products, such as hydrogen chloride (HCl), sulphur dioxide (SO₂), hydrogen fluoride (HF), lead (Pb), mercury (Hg), and Dioxins.

Typical Uses

Our filtration plants are used in multiple applications and industries, such as:

  • Incineration
  • Cremation
  • Gasification & Pyrolysis
  • Biomass Combustion
  • Nuclear Waste Processing
  • Mineral Processing and Smelting
  • Coal Drying
  • Cement Production
  • Foundry Processes
  • Waste-to-Energy

Why choose Macrotec?

Macrotec’s extensive experience with combatting all types of emissions has given us a unique perspective in filtration and filtration technologies. In order to strengthen our product offering and expertise, we have teamed up with Glosfume, a UK company that are the world leaders in hot gas filtration.

Together we have the experience, expertise, and product offerings for a wide array of industry applications.

Our Filtration Systems

Macrotec provides three different filtration systems; our very high temperature MacroCeramic filters for up to 900°C, Glosfume filters for up to 450°C for the lowest emissions, and Glosfume biomass filters.

Standard filter sizes go up to 9800 Am³, but with all filters being modular units can be linked for extremely large processes. The modular units also allow for easier installation, lower transport costs, flexible installation footprint, high redundancy, and easy maintenance.

How does Hot Gas Filtration work?

Our filtration units work by drawing the flue gas through hollow ceramic filter elements, capturing particles on the filter wall. The structure of the filter elements is so fine, even PM 2.5 are captured.

The filtration unit is split into “dirty” and “clean” compartments, with the flue gas entering on the “dirty” side and particulate matter being captured on that side of the filter element. Clean air then passes from the filter element into the “clean side” and out to the stack.

The filter elements are periodically cleaned down with reverse pulse cleaning using compressed air, discharging the built-up particles to a collection bin

Advantages of Ceramic Filtration

  • Ceramic elements can withstand temperatures of up to 1,000°C, compared to 140°C to 260°C for bag filters.
  • Non-flammable.
  • Totally resistant to acids and alkalis.
  • Operating temperature of up to 450°C (Glosfume units), and 900°C (MacroCeramic), allowing for scrubbing at the most efficient temperatures and almost all processes.
  • No need for reaction towers or cyclones.
  • Lowest emission level achieved, with constant and reliable performance.


Our Ceramic Filter Elements

Filtration, Hot Gas Filtration, Low Emissions, Toxic Emission RecoveryThe key to Macrotec’s filters are our filter elements, which are designed and manufactured by Glosfume. These elements are able to operate at temperatures of up to 1,000°C, at a 99.99% efficiency, and are able to remove sub-micron particles.

For optimum performance and reliability, all Glosfume filter elements are formed from engineered fibres using a fully automated process. During manufacture, forming times and pressures are strictly maintained to achieve stable pressure drop and bulk density. Every tenth element manufactured is tested and recorded, then packed in bar coded packaging to ensure complete traceability.

For the best possible performance, each element is fully machined to high tolerances. A specially formed surface allows dust to form a conditioned layer that assists the removal of submicron particles. Gas flow is improved, and more evenly distributed, by the unique tapered profile of each element. The taper makes it easier to clean the filter element.

Dry Gas Scrubbing

Our filters we use are designed with gas scrubbing in mind, with our Filter Plants able to easily incorporate sodium bicarbonate and activated carbon. These are used to neutralise acid gasses such as HCL, HF, SO₂, and adsorb dioxins and heavy metals, such as mercury and lead.

Our filtration units are also designed for optimal performance of Sodium Bicarbonate for its effective range of 140°C to 450°C, while operating at higher velocities and thus there is no requirement for reaction towers or other ancillary equipment for effective dry scrubbing. Filters are modelled using CFD software to ensure even distribution and retention of the scrubber for optimal reaction.

An additional benefit of dry gas scrubbing at temperatures above 400° is that reformation of dioxins are prevented. This cannot be achieved by bag filters, which operate between 140°C to 260°C due to ignition risk of the media.