Energy saving, thermal separation

Steam turbines provide opportunities for process improvements and energy savings. There usually are four separate and redundant process controller packages that perform operator automatic control (OAC), thermal... 

The development of thermally coupled systems started with attempts to find energy-saving schemes for the separation of ternary mixtures into three products. One of the first industrial applications was the side rectifier configuration for air separation. The side stripper configuration followed naturally. By combining the two we obtain the fully thermally coupled system of Petlyuk, Platonov, and Slavinskii [Int. Chem. Eng., 5, 555 (1965)] see Fig. 13-67h. It consists of the prefractionator which accepts the ternary feed stream followed by the main column that produces the products (product column). 

As an example, the annual production of 20,000 t/a coffee with activated carbon caffeine separation involves the loss of more than 200 t of caffeine, since this potential by-product is destroyed during the thermal regeneration of the adsorbent. The questions of energy-saving and of the economic recovery of CO2 are also of interest for large-scale plants which already exist or which are still to be designed. 

The main advantage of the biphasic Difasol process remains the ease of product separation that can be performed in a subsequent step. There is no co-miscibiHty between the products and the IL thus, product separation by settling does not require heating and results in energy saving plus reduced loss of catalyst by thermal decomposition. 

The importance of membrane processes in separation technology is steadily increasing. Membranes separate a feed mixture into a permeate, that is, the part of a stream which passes the membrane, and a retentate, which does not pass the membrane (Figure 9.2). In thermal process engineering, membrane separations are often an energy-saving alternative for the separation of azeotropes, as the separation effect is almost independent from the vapor-liquid equilibrium which is used in distillation. The two components separate because of their different ability to pass the membrane, which is illustrated in Figure 9.2. 

The boiler itself should be very efficient to generate steam and for this preparation of oil, air to fuel ratio, stack temperature of flue gases, conversion of furnace oil to LSHS oil, maximum condensate recovery, cleaning of the fire side, replacement of old boilers etc. are the various important factors to be taken care-of. Factors responsible for optimum consumption of steam such as supply of steam at correct pressure, provision of pressure reducing valves, water separators in steam lines for supply of dry steams at requisite pressure, selection of trap of right type and size for efficient recovery of condensate etc. should be considered for the saving of thermal energy. 

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