16

a 125-300 h, submerged, stirred.

a 125-300 h, submerged, stirred.

that has been generated on CFCCs except for some that is included in the earlier application section. In most cases, corrosion data was generated with a particular application in mind. Application-oriented data includes simulation of filters, heat exchangers, steam cracker materials, chemical pump housings, and gas turbine combustor liners.

A chemical company is evaluating CFCC filters to remove silicon from a stream of moist hydrogen chloride and another stream containing various chlorosi-lanes. Success would eliminate the need for additional, very large, bag houses. The facility would substantially benefit both in process stream efficiency and effluent cleanup from improved high-temperature filtration technology. CFCCs have withstood over 1000 h in each of these extremely corrosive streams, at 290°C (550°F) and 1040°C (1900°F), respectively.

CFCC filter samples consisting of rings, cut from candle filters (wall thickness approximately \ in.), measuring 2.5 cm in height and 7.5 cm in diameter were placed in each gas stream. Moist hydrogen chloride gas passed over each sample at a rate of 9.6 cm3/min plus 887 cm3/min of mixed gas of nitrogen, oxygen, carbon dioxide, and water vapor, in an operating temperature of 1040° C, simulating the operating environment. After 1000 h exposure, the burst strength of the CFCC rings were tested at room temperature and compared to pretest strength. The CFCC retained 65% of its original strength in this extremely corrosive environment (Fig. 3.16).

In the other filter test, chlorosilanes were passed over CFCC rings at a rate of 500 cm3/min of methyl chloride plus 2.7 mL/min of dimethyldichlorosilane.

Environmental Exposure System

□EL Mass Flow Controller

<>TO Three-Way Solenoid Valve

_P_ Solenoid Valve

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