Pure solid sugar is recovered from sugar cane in a process that has multiple steps. Among all the steps, three steps are considered here (see figure below). A screen is used to separate pulp (solid material) from sugar and water. In the evaporator, a portion of the water is removed. The remaining water is removed in a crystallizer, Stream 1 Screen Stream 2 6250 kg/h 6500 kg/h 7250 kg/h Stream 3 7500 kg/h Stream 4 Pure Water Vapor Evaporator Stream 5 Stream 1 contains 14 mass percent sugar, 16 mass percent pulp, and the remaining is water. All the pulp in Stream 1 goes to Stream 2. Stream 2 contains 96 mass percent pulp. Stream 3 contains no pulp, 16 mass percent sugar, and the remaining is water, and is sent to the evaporator. Stream 4 is pure water. Stream 5 contains sugar and water and is sent to the crystallizer. Pure water (Stream 6) leaves the crystallizer at a rate of 1500 kg/h and pure sugar (Stream 7) leaves the crystallizer at a rate of 1000 kg/h. The process operates at steady state. What is the total flow rate of Stream 1 entering the screen? Crystallizer Stream 6 Pure Water Stream 7 Pure Sugar

One way to make coal “cleaner” is to gasify the coal into “city gas”. In a proposed molten-iron coal gasification process pulverized coal of up to 3 mm size is blown into a molten iron bath and oxygen and steam are blown in from the bottom of the vessel. Materials such as lime for settling the slag, or steam for batch cooling and hydrogen generation can be injected at the same time. The sulfur in the coal reacts with lime to form calcium sulfide, which dissolves into the slag. The process operates at atmospheric pressure and 1400 to 1500°C. Under these conditions, coal volatiles escape immediately and are cracked. The carbon conversion rate is said to be above 98% and the gas is typically 65 to 70% CO, 25 to 35% hydrogen, and less than 2% carbon dioxide. Sulfur content of the gas is less than 20 ppm. Assume that the product gas is 68% Co, 30% H2, and 2% CO2. Calculate the enthalpy change that occurs on the cooling of 1000 m3 of the gas at 1475 °C and 1 atm to 25°C and 1 atm.

The vapor leaving the top of a distillation column goes to a condenser in which either total or partial condensation takes place. If a total condenser is used, a portion of the condensate is returned to the top of the column as refcr and the remaining liquid is taken off as the overhead product (or distillate). If a partial condenser is used, the liquid condensate is returned as reflux and the uncondensed vapor is taken off as the overhead product. The overhead product from an n-butane-n-pentane distillation column is 93 mole% butane. The temperature of the cooling fluid limits the condenser temperature to 39 °C or higher. REFLUX DRUM a) Using Raoult's law, estimate the minimum pressure at which the condenser can operate as a partial condenser (i.e., at which it can produce liquid for reflux) b) The production rate of overhead product is 50 kmol/h, and the mole ratio of reflux to overhead product is 2:1. Calculate the molar flow rates and compositions of the reflux stream and the vapor…

4. [Scrubber]. A coal-fired combustion system produces flue gas that contains particulate matter. To reduce the amount of particles, the flue gas is treated in a scrubber. The measurement of the mass and size of the particles at the inlet and outlet of the scrubber yielded the size distribution data given in the following table: Particle diameter [um] (size interval: dlower → dupper) 0.10.25 0.25 → 0.5 0.5 → 1.0 1.0→2.0 2.05.0 Formulas for question 4: . Particle mass at scrubber inlet [mg] 623 55.4 12.6 8.9 7.1 5.0 10 7.7 10 →30 6.6 30→ 50 4.3 The mass of particles in each size interval was measured on a basis of 1 m²³. 31.4 33.2 123 a) What is the overall efficiency of the scrubber? [Ans: noverall 96.7 %] b) Calculate the collection efficiency (na,i) of the scrubber and the particle geometric average diameter (dpi) for each size interval. Create a graph showing the variation of na,i with dp,i. (PTO) efficiency: nd,i (%) = - 394 775 1055 c) Calculate the mass-average diameter of the…