Ceramic Fiber Technology Facilitates Advancement in Hot Gas Filtration

Tri-Mer Corporation (USA) has introduced “UltraTemp Filtration,” a hot gas filtration system that filters fine particulate to extremely low levels.

The heart of the UltraTemp Hot Gas Filtration system is a new generation of ceramic filters. Earlier generations of ceramic filters –sometimes called “candle” filters – were manufactured from high-density granular powders similar to common ceramic products. While effective, they were brittle, with low thermal shock resistance, and were prone to cracking and breakage from thermal shock. As a further drawback, these older ceramic filters were sometimes hard to keep clean under continuous operation.

Now, with advances in fiber and ceramic technology, these issues have been overcome. The filters used in the Tri-Mer UltraTemp Filtration system are manufactured from a new generation of low-density ceramic fibers that provide exceptionally high resistance to thermal shock. This makes the filters very ductile and resistant to crack formation.

The unique composition of the ceramic fibers give the UltraTemp filters an exceptional ability to capture fine particulates at the fiber surface, without blinding. They are thus easy to clean using standard pulse-jet techniques. Being fibrous, rather than granular, the filter elements are also lightweight and very robust for installation and handling. They have high porosity with low resistance to flow, which minimizes the number of elements required for a given application.

The UltraTemp Filtration system provides optimal filtration for gases between 400°F and 1000°F, and in most cases can be applied to hot gas streams up to a maximum operating temperature of 1650°F. Typical filtration results are 0.001 grain/dscf (2 mg/Nm3); many results are a fraction of this typical value.

UltraTemp Filtration is compatible with heavy inlet loadings, often above 1 grain/ dscf (2300 mg/Nm3). Certain applications involving three or four times this inlet loading still achieve outlet levels of less the 0.001 grains/dscf. The ceramic filters are almost completely chemically inert and highly corrosion-resistant.

Applications of the Tri-Mer UltraTemp Filtration system include glass production, waste incineration, and biomass pyrolysis. UltraTemp Filtration is also an excellent way to achieve ICI boiler MACT compliance for coal, biomass, and wood. Other applications include metal smelting, mineral processing and chemical production.

The Tri-Mer UltraTemp Filtration system features an option for dry injection of calcium or sodium-based sorbents for the capture of acid gases. Injected in the duct upstream of the filter modules, the additional sorbent particulate is easily captured along with its pollutant gas. For these applications, SO2 removal is typically 80% or better, with removal efficiencies as high as 97%. HCL removal is typically 95%, and often as high as 99%.

If the need is NOx, VOC, or dioxin removal, UltraTemp filters elements are available with catalysts embedded in the filters themselves. Urea is then injected upstream of the filters. NOx removal in these systems is typically above 90%. VOC oxidation and dioxin removal are also both exceptionally high. UltraTemp Filtration can incorporate both sorbent injection and catalyst reduction in a single system. Acid gases, such as SO2, and NOx can be simultaneously removed in the same system.

Tri-Mer’s UltraTemp Hot Gas Filtration system uses a baghouse configuration with a reverse pulse-jet cleaning action. The filters are back-flushed with air, inert gas, syngas, or other appropriate gases. It has a reliable sealing mechanism that is easy to access, and the design has been engineered for easy installation and maintenance. Filter elements are manufactured in various sizes, the largest of which is ten feet long and six inches in diameter, including an integral mounting flange.

The UltraTemp Filtration system is an efficient, proven approach for hot gas filtration with over 400 applications worldwide.