PERFORMANCE OF HIGH-TEMPERATURE FABRIC FILTERS UNDER GASIFICATION ANDCOMBUSTION CONDITIONS

Experimental filtration tests were carried out in a hot gas filtration facility with two different dusts (coal ash and gasifier char) using high-temperature fabric filters made from Nextel(TM) 312 ceramic fiber s. The filtration efficiency and conditioning behaviour of these filte rs were investigated for a variety of operating conditions, including face velocity, solids loading, temperature, pulse duration and maximum pressure-drop setting under both reducing and oxidizing conditions si mulating gasification and combustion, respectively. Significant differ ences in the conditioning behaviour of the fabric filter were observed with the two types of dust. Pressure-drop variations as a function of time were investigated for a variety of conditions. A drastic decreas e in the pulse interval and a linear increase in the baseline pressure drop were observed when the face velocity was increased, The test res ults showed that the filtration efficiency was primarily affected by t he face velocity. The filter bags demonstrated high filtration efficie ncies (i.e. 99.95-99.99%) for a face velocity in the range of 12-24 mm s(-1). At a face velocity of 40 mm s(-1) the filtration efficiency wa s reduced to 99.5%. (C) 1997 Elsevier Science B.V.