Question

1. There are several evaporators, including agitated film evaporator, long-tube evaporator, short-tube evaporator, and horizontal-tube evaporator. For (a) juice and (b) paste, suggest proper evaporator and explain why you select it. 2. A double-effect forward-feed evaporator is used to evaporate a sugar solution containing Swt solids to a concentrated solution of 25 wt%. The boiling-point rise (BPR) of the solution (independent of pressure) can be estimated from BPRC-1.5x + 6x", where x is wt% of sugar in solution. Saturation steam is at 205kPa. The pressure in the vapor space of the thefd effect is 20 kPa. The feed rate is 22000kg/h at 270. The heat capacity of the liquid solution is a constant as c-4.19 kJ/kg. K. The heat of solution is negligible. The coefficients of heat transfer are U-Uy-2000 W/m²K (a) Sketch the diagram and mark all the streams of this evaporator. (b) Carry out the material balance for overall materials and solute to evaluate the amount and weight fraction of every stream. Describe the assumption you make in this balance process. (c) Derive the boiling point raise (BPR) in two effects respectively (d) Derive the temperature of two effects. (e) If each effect has the same surface area, calculate the area, the stream rate used and the steam economy. (Describe the trial and error procedures you would perform). A.2-9 Properties of Saturated Steam and Water (Steam Table), SI Units Specific Volum u hay Temper Vapor ) kek) ನಗೊr. C e) Liquid Sard Vaper Liquid Sardapor Liquid Sard Vape 3.169 0.001002943.360 1 04.89 2547.2 0.3674 8.5580 3.567 0.0010035 38.774 113.25 2550.8 -0.3954 8.5156 4.246 0.0010043 32.894 125.79 25563 0.4369 8.4533 5.034 0.0010053 28.011 138,33-2561.7 0.4781 8.3927 5.947 0.0010063 23.940 150.86 2567.1 0.51888.3336 7.384 0.0010078 19.523 1 67,57 167.57 25743 25743 05725 0.5725 8.257 9.393 0.0010099 15.258 188.45 2580.2 0.60878.16 12.349 0.0010121-12.032 20933 2592.1 0.7038 8.0083 15.758 0.0010146 9.568 2 30.232600.9 0.7679 79953 19.9400.0010172 7.671 251.13 2609.6 0.8312 7.5095 25.03 0.0010199 6.197 272.06 2618.3 0.8935 78319 31.19 0.0010228 5.042 2 92.98 2626. 8 0.9549 7.7553 38.58 0.00102594.131 313.93 26353 10155 7604 47.39 0.0010291 3.407 334.91 3643.7 1.0753 7.6122 57.83 0.0010325 2828 355.90 2651.9 1.1343 75445 - 70.14 0.0010360 2361 376.922660. 1 1.1925 7.4730 84.55 0.0010397 1.9819 397.962668.1 1.2500 7.45 101.350.0010435 1.6729 419.042676.1 13069 7350 a 88 $ USB 100

Answer 1

sit Exuperators : i; Agitated film evaporatus i Lony tube evaporatus in short tube evapratos in Hanzonteel - tube evaporates az Julie: "Ag, Hated film evaperatus" & Fathday phon suportes this type of evapuntos is should be used. This evaporatus generally used for heat sensitive materiale such as orange juice and uthes fruit juice. This is also Modified falling film evaperatus, and in In the due to Heat sensitive Materials Heart troustes ruffrent and turbulence is increased by mechanical agitation liquid film, and due to lowes lowes residence residence time time and and lowes hold up to and due to this lowes powes Consumption line this evaporatus is used. 7. Paste! Horizontal tube evaporatus", the evoperators is used. This evaporatus is used for viscous fluid. In this exuperatus fead is fed to the top of Calandna through efficient Iranied distributors and steam is given on shell side and concentrated is collected cut buttem. Because of lorge units for handling high evaporation load this evaporatos is suitable for viscous Material,