Low-Back Pressure of the CerX Ceramic Fiber Filter Cartridge
Competitive commercial high temperature ceramic filters are solid ceramic shapes with very fine pore sizes (1 to 10 micrometers) for filtration and 40% to 50% total porosity. This type of ceramic or metal filter system compensates for the high resulting backpressure by providing a large array of cartridges to reduce the total backpressure on the system.
The CerX ceramic fiber filter is comparatively open with 10 to 75 micrometer pore sizes and 85% total porosity. The CerX high-porosity exhibits 1/5th to 1/10th the backpressure of the competitors by using depth filtration, where particles adhere to a high surface area of fibers while passing through the large pores – resulting in the same filter efficiency as the small pore size ceramic and metal filters. The particulate loading of the CerX filter media is increased by using a dual-layer filter media, as shown below.
A comparison of the properties of the two types of high-temperature ceramic filters is seen in the following table:
Filtration Efficiency That Exceeds 95%
The thickness of the CerX filter media determines the length of the mean free path that a particle must travel through the ceramic fibers. The fiber diameter and the filter media thickness (number of layers of fibers) is engineered to assure that greater than 95% of the particles adhere to a fiber before exiting on the “clean” side of the filter. Test measurements on diesel particulate filtration are displayed in Figures 2 and 3 as conducted by an independent laboratory.
Catalyst coatings can be added to the fiber surfaces to achieve additional filtration efficiency to chemical reactions during filtration.
CerX Ceramic Fiber Filter Media – High-temperature ceramic fibers, bonded by a patented ceramic process will provide the same particle removal efficiency as all of the technologies described below. The key differences are:
- The CerX cartridges can trap particulate at any temperature from ambient to 1,000°C. No addition of auxiliary heat is needed.
- The clean filter backpressure of the CerX filter cartridge is approximately 1/10th that of candle filters, significantly reducing the amount of filter media necessary.
- An CerX filter cartridge system can be coated with an oxidation catalyst to be continuously cleaned in +400°C exhaust streams. If the filter cartridge is exposed to sticky or oily particulate, it can be periodically cleaned in situ with the application of a short 400°C to 600°C auxiliary heat source and quickly returned to operation.
- The CerX system can be equipped with the high-pressure air back-pulse to remove ash in the same way that candle filters operate.
High-temperature gas filtration and exhaust particulate control has been limited to:
Thermal Oxidizers – An oxidation catalyst is coated on ceramic honeycomb substrates and the particulate-laden exhaust stream requires heating by natural gas burners to reach the effective temperature of the oxidation catalyst. This auxiliary heating consumes expensive quantities of natural gas during the entire operation of the industrial process. High maintenance is encountered when the catalyst surface is coated with “sticky” particulate or oily contamination. The catalyst substrate must be removed and chemically cleaned or replaced.
Ceramic or Metal Candle Filters – Near solid formed tubes with fine porosity can withstand the high-temperature exhaust. The density of these tubes exhibit a high backpressure which requires a large number of candle filters to accommodate the low backpressure of most industrial filtration processes. If the particulate is dry, high-pressure air back-pulses can remove the particulate from the candle filters. However, similar to the thermal oxidizers, sticky or oily particulate rapidly fouls the candle filters, requiring removal and chemical cleaning or replacement.
Electrostatic Precipitators – The electric charging of particles through a grid and collection on grounded collector plates is a highly efficient and well-proven method of removing particles from an exhaust stream. This device is limited to cooled exhaust to limit damage to the electrical components and experiences high maintenance costs when the electrical components are fouled by sticky or oily particles.
External Third Party Lab Results for Air and Oil
High Temperature and Corrosive Engineered Solutions
The CerX engineering group has 30 years of experience in the material science and acceptable uses of metal and ceramic materials in harsh environments. Our engineering design group is capable of designing filtration systems to incorporate these filter materials in complete working systems. ICS can fabricate these systems and install them at a customer site for testing. Furthermore, CerX is located 15 minutes from Oak Ridge National Laboratory where we extensively use their world-class people and analytical equipment in CerX product research and development. CerX is equipped to provide working prototypes for all types of industrial and vehicle gas filtration challenges.
The Company is experienced in providing costs and schedules for systems development planning. We can then perform the program independently or with customer assistance. Our rates are those of a small business with low overhead.