Abstract
This paper discusses some of the problems encountered in the operation of the Crawford Ave. Station of the Commonwealth Edison Co. This station is designed for 550 lb. steam pressure at the turbines and 725 deg. fahr. temperature. The fuel used is central Illinois coal having an average heat value of 10,255 B.t.u. This is fired on forced-draft, chain-grate stokers.
In the first three units the steam is reheated after passing through the high-pressure turbine by means of a special reheat boiler on each unit. The specified reheat temperature is 700 deg. The fourth unit has no reheat. The first three turbine units are bled at three points and the fourth at four. The boilers are of the interdeck superheater type, built by the Babcock & Wilcox Co., with a capacity of 150,000 to 200,000 lb. of steam per hour.
Unit No. 1, 50,000 kw., built by Parsons Co., England, was put into service in May, 1925. Unit No. 2, 60,000 kw., built by the General Electric Co., was put into service in November, 1924. Unit No. 3, 50,000 kw., built by the Westinghouse Co., was put into service in March, 1925. Unit No. 4, 75,000 kw., built by the General Electric Co., was put into service in August, 1926. Unit, No. 5, 90,000 kw., built by the General Electric Co., is under construction, and will be put into service in August, 1927. Unit No. 6, 100,000 kw., is on order with the Westinghouse Co., and will be in operation in the summer of 1928. Detailed description of the station has been given in various reports and printed articles, so it is considered unnecessary for this discussion.
