FUEL COST CHARGED TO DESALTERS IN COGENERATION POWER-DESALTING PLANTS

In combined power-desalting (plants, high available steam (at high pre ssure and temperature) is expanded first in a steam turbine (and thus produces work) before its extraction (from the turbine) as a heat sour ce to the desalters. The amount of energy consumption charged to the p redominantly used multi-stage hash (MSF) desalter in this combined hea t and power plant is a question of great concern in the Gulf area. The following are among the methods used to answer this question: (i) the available energy of the heat supplied to the desalter; (ii) work loss from the lower pressure stages of the steam turbine due to steam extr acted to the desalter; (iii) energy charged if a separate boiler was u sed to supply the desalter with its required heat; and (iv) the excess energy supplied to the combined power desalting plant as compared to a single purpose power plant producing the same power output. There wo uld be a different rating method of the power producing process associ ated with any of the above mentioned charging methods. In this paper, the MSF desalting method and its power consumption are outlined, toget her with the rating method of the power-desalting plants and the energ y charged to the desalter methods. These rating methods are applied to real cases of dual purpose plants Working in Kuwait.