Characteristics and characteristics of ultra high temperature filter media
Early silicon aluminum ceramic fiber ketone, traditional textile and non-woven fiber as the filter material. Ceramic textile fibers were developed in 1970s, consisting of aluminum, boron and silicon. After nearly 30 years of continuous improvement, its new generation of ceramic fiber filter bag can withstand nearly 800 degrees of high temperature. At present, ceramic textile fiber filter bag has been used in many high temperature flue gas purification. Although the performance of ceramic textile fiber bags has been greatly improved, the biggest problem of this ceramic filter is that the fiber is brittle and easy to break.
Chemical vapor reaction (CVR) method. It is using B2O3 as the raw material by melt spinning is made of B2O3 heating low concentration ammonia, ammonia and ammonia to generate B2O3 boron reaction intermediate compounds, then the crystal type of unstable fiber under tension further in the mixed gas ammonia or ammonia and nitrogen in heating to 1800 DEG C, which is converted to BN fiber, its strength can be as high as 2.1GPa, modulus 345GPa.Chemical vapor deposition (CVD) method. The boron fiber is heated to 560 DEG C for oxidation at first. Then the oxidized fiber is heated to 1000-1400 DEG C in ammonia, and the BN fiber can be obtained by reaction about 6h.Organic precursor method. The fibers are made from a spinning process made from poly (urethane), which is crosslinked to produce non - melt fibers, which are then cleaved into fibers.
There are two kinds of Si3N4 fiber preparation method: one is to chlorosilane and six methyl two silicon nitrogen as the starting material, the first synthesis of hydrogenated stable polysilazane fibers by melt spinning, by melting and burning Si3N4 fibers; two with pyridine and two chloro silane as raw materials, the reaction of white the solid adducts under the protection of inert gas, and then get the whole solution of ammonia cyanide polysilazane in nitrogen, dissolved in organic solvents with hydrocarbon into the spinning solution made of fiber by dry spinning, and then in an inert gas or ammonia at the temperature of 1100-1200 DEG C for heat treatment and silicon nitride fiber.SiBN3C fiber is also produced by pre polymerization method. It is the newest ceramic fiber. The starting material is poly silicon nitrogen. It is obtained by melt spinning, cross-linking, melting and cracking.SiO2 is mainly through the same fiber and preparation of high silica glass fiber process, first made of glass material, then two times of melting, melt spinning with platinum crucible, a temperature of about 1150 DEG C, are further processed into fibers or fabrics and other products postprocessing with hot hydrochloric acid, get rid of B2O3 the composition of HNa2O, the sintering mass fraction of fiber in SiO2 reached 95%-100%, in addition, there are configured using SiO2 as raw material, high viscosity of the sol after spinning, obtained precursor fibers, and then heated to 1000 DEG C can be obtained with 99.999% purity quartz fiber. In addition, the quartz rod or the oxyhydrogen flame can be fused into coarse fiber, and then the continuous fiber with a diameter of 4-10 mu m can be drawn into a continuous fiber with a constant speed through an oxyhydrogen flame or a gas flame, and the content of SiO2 is 99.9%.
