Thermo-compressor

FIGURE 32.13 Osmotic dehydration with re-concentration of hypertonic solution (1) feeding conveyor (2) osmotic dehydrator (3) redler conveyor (4) heat exchanger (5) scraped surface evaporator (6) thermo-compressor (7) driven wheel flow of hypertonic solution —, vapor =>, high pressure steam -heating steam). 

In the absorption system at double stage, shown in Figure 4, the displacement of the refrigerant from low pressure to high pressure by means of two thermo-compressors 1 and 2 combined in series. To analyze the cycle of transformations, we consider the following assumptions ... 

In this installation, the first thermo-compressor transpwrts the refrigerant from low pressure Pf to an intermediate pressure Pi corresponding to a saturation temperature of the refrigerant, Ti. Mass titles are respectively xu and Xpi for rich and pxror solutions. 

The second thermo-compressor transports the refrigerant of intermediate pressure Pi to the condenser pressure Pc. Mass titles are resprectively xr2 and xp2 for rich and poor solutions. 

The SMART and MED-TVC units are connected through the steam transformer. The steam transformer produces the motive steam using steam extracted from the turbine and supplies process steam to the desalination plant. A steam transformer also prevents contamination of the produced water by hydrazine and radioactive material of the primary steam. The steam transformer is made of horizontal tube bundles the primary steam flow is condensed inside the tubes at its saturation temperature. The feed brine is sprayed outside of the tube bundles by the recycling pump. Part of the sprayed water is evaporated and the produced steam is used as the motive steam for the thermo-compressor of the evaporator. Part of the condensate in the first cell of the evaporator is used as make-up for the steam transformer and this makeup water is preheated by the condensate of the primary steam before being fed into the steam transformer. The pre-heater is a plate-type heat exchanger made of welded titanium. 

Part of the vapour produced in the fourth stage is drawn up at 46 C and 0.10 bar by the thermo-compressor, which compresses it with high pressure steam at 0.22 bar to feed the first stage. The condensed vapour from each evaporator stage and from the condenser stage is extracted by a pump to form the product water. Thermo-compression distillation plants can produce very pure water from any sea water or brackish source without a complex pretreatment or filtration. 

It is impossible to arrive at generalized guidelines at the present time regarding the technoeconomics of steam compression by thermo-compression (e.g., steam jet ejectors) versus mechanical recompression for steam-drying plants. The costs of installation of such systems are such that they should be considered only for large-scale continuous steam dryers, that is, those with evaporation capacities of 100 tons/day or higher. The steam compressors for such service are expected to cost over 500,000 (1990 estimate for North America). To this, one must add the costs of spares and maintenance. 

Fig. 13.5 A photograph of the laboratory equipment setup for combustion of raw rice husks in fluidized bed reactor (1) air compressor B/ac Decker, (2) tank for liquid petroleum gas (LPG) (3) distributor for gasses (4) manometer (5) air Rota meter (6) quartz fluidized bed reactor (7) gas burner (8) asbestos insulator (9) porous quartz diaphragm (10) electrical heater (11) electrical transformer (12) voltmeter (13-15) thermo couples (16) economizer (17) separatot (18) temperature recorder (19, 20) thermo regulators and (21) PC...

The Chemico Thermo-Urea process employs centrifugal compressors to recycle the carbon dioxide, ammonia, and water vapor to the reactor (Fig. 28.21). The reactor effluent is passed into a separator from which the hot gases pass to the compressor, and the liquid effluent enters a carbamate decomposer... 

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