Graphite Heat Exchangers

Impervious graphite heat exchangers machined from solid blocks are also available (15,16). The solid block constmction is less susceptible to damage by mechanical shock, such as steam and water hammer, than are shell and tube exchangers. Block exchangers are limited in size and cost from 50—100% more than shell and tube units on an equivalent area basis. 

Impervious graphite heat-exchanger equipment is made in a variety of forms, including outside-packed-head shell-and-tube exchangers. They are fabricated with impervious graphite tubes and... 

HILLIARD, A. Brit. Chem. Eng. 4 (1959) 138-43. Considerations on the design of graphite heat exchangers. 

Inasmuch as furfural and furfuryl alcohol resinify with acids to form insoluble products, this reaction affords an excellent means of impregnating porous materials such as carbon or graphite artifacts with a subsequent formation of a resin in situ. This is a widespread application in the production of carbon or graphite electrodes for steel furnaces and in the production of graphite heat exchangers for the chemical industry. 

The process gas is further cooled in the condensing tower (4) by circulating weak acid which is cooled externally in impervious graphite heat exchangers (5). Entrained droplets of acid mist are removed from the gas in electrostatic precipitators (6). Drips from the precipitators are returned to the gas cooling tower. 

Finned double pipe heat exchanger Doss-bore (all graphite) heat exchanger Thermascrew (Reitz) single screw conve> or... 

The HQ gas is cooled in a graphite heat exchanger and absorbed in water in two stages to produce 33% hydrochloric acid as a byproduct. The process gives an excellent quality that contains over 50% K 0 and less... 

The dilution loop consists of a centrifugal circulation pump with impervious graphite housing and impervious graphite heat exchangers. All pipework should preferably be of mild steel lined with polytetrafluoreAylene (PTFE) because of the corrosivity of the acid mixture, containing 80% sulphuric acid. 

The experience of zirconium in peroxide production led FMC to replace the graphite heat exchangers with zirconium shell and tube exchangers used in the manufacturing of acrylic films and fibers. In this application, the H2SO4 concentration was as high as 60% at 150°C. 

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