Air-cooled steam condenser

Air-cooled steam condensers, which are used primarily where adequate supplies of cooling water are not readily available, as in desert and scrubland areas, and where water resources must be shared with sizable local populations. 

The superheated steam goes to the steam turbine generator, produces electricity, and is condensed producing boiler feed water. The steam condenser is usually a shell and tube type heat exchanger supplied with cooling water. Alternatively, air-cooled steam condensers can be used. 

Air-cooled surface condensers. Figure 8.11 shows a surface condenser elevated above the steam turbine. This creates an additional problem, in that moisture from the turbine exhaust steam will accumulate in the bottom of the turbine case. A special drain line from the turbine s case is needed to prevent condensate backup from damaging the spinning wheels. 

The turbine case pressure was increased by raising the pressure in the air-cooled surface condenser. This was accomplished by shutting off several of the air fans, which, in turn, increased the condensing temperature of the exhaust steam. But why would raising the turbine case pressure drain the turbine, anyway After all, increasing the surface condenser pressure also increased the pressure in the drum that the turbine case drained to. 

Multi-Stage Arrangement of Condensation in Air-Cooled Steam Power Stations)... 

Human hair (Note i) is freed from foreign matter (Note 2), washed well with a lukewarm solution of soap (Note 3), then twice with cold distilled water, and dried. This washing removes the natural oils from the hair (Note 4). Two kilos of the dry, washed hair is pushed into a 12-I. round-bottom Pyrex flask, and 4 1. of 20 per cent hydrochloric acid (Note 5) is added. An air-cooled reflux condenser, consisting of a wide glass tube, is attached to the flask. The hair is hydrolyzed by heating on the steam bath (Note 6) until the biuret reaction is entirely negative this requires one hundred twenty to one hundred forty-four hours. 

Hexachloro-l,3-difluoropropane (CCI2FCCI2CCI2F). 0 In a round-bottomed flask equipped with an air-cooled reflux condenser a mixture of 1500 g. of octachloropropane, 560 g. of antimony, trifluoride, and 75 g. of antimony pentachloride is heated for five hours on a steam bath. A further quantity of 100 g. of antimony pentachloride is then added in small portions, and the heating is continued for twenty hours. The reaction mixture, which gradually becomes homogeneous, is allowed to cool before it is poured into aqueous acid, then is washed and dried. The crude product amounts to 1092 g., from which about 750 g. of difluoride is obtained by fractional distillation at 90 mm. The boiling. point at 760 mm. is 194°, and the freezing point is 29.8°. 

Free Fatty Acids (as stearic acid) Transfer 2 g of sample, accurately weighed, into a dry, 125-mL Erlenmeyer flask containing 50 mL of acetone, fit an air-cooled reflux condenser onto the neck of the flask, boil the mixture on a steam bath for 10 min, and cool. Filter through two layers of Whatman No. 42, or equivalent, filter paper, and wash the flask, residue, and filter with 50 mL of acetone. Add phenolphthalein TS and 5 mL of water to the filtrate, and titrate with 0.1 A sodium hydroxide. Perform a blank determination (see General Provisions) using 100 mL of acetone and 5 mL of water, and make any necessary correction. Each milliliter of 0.1 A sodium hydroxide is equivalent to 28.45 mg of stearic acid (CigH gOi). Lead Determine as directed in the Flame Atomic Absorption Spectrophotometric Method under Lead Limit Test, Appendix NIB, using a 10-g sample. 

These are required for continuous removal of gases entering in equipment and air from steam condensers in thermal power plants so that proper vacuum and the condensation rate can be maintained, crystallising out certain salts from their solutions (sodium sulphate crystals by cooling of concentrated solution), non-condensable gases from solutions being evaporated under vacuum conditions, etc. 

Amine-stripper overhead condensers are typically air-cooled, fin-fan exchangers. Their duty can be determined from the concepts in Chapter 3 as required to cool the overhead gases and condense the overhead steam... 

Figure 10-177. Air-cooled Stac-Flo steam condensers illustrating process system. Representative types of tubes are illustrated. (Used by permission Bui. M-390621 10/90. Hudson Products Corporation)...

Christman, J., Vacuum Steam Condensers Air vs. Water Cooling, Hydrocarbon Processing, Sept. (1980) p. 257. 

On this system, the turbine is speed controlled and passes steam, depending on the electrical demand. The bypass-reducing valve with integral desuperheater makes up any deficiency in the steam requirements and creates an exhaust steam pressure control. Alternatively, any surplus steam can be bypassed to a dump condenser, either water or air cooled, and returned to the boiler as clear condensate. 

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