Process Calculations GATE-1995
Q 1: An evaporator while concentrating an aqueous solution from 10 to 40% solids evaporates 30000 Kg of water. The amount of solids handled by the system in Kg is
Q 2: 1000 Kg of wet solids are to be dried from 60% to 20% moisture (by weight). The mass of moisture removed in Kg is
Q 3: Assuming that CO2 obeys perfect gas law, calculate the density of CO2 (in Kg/m3) at 263° C and 2 atm.
Q 4: Pure O2 is mixed with air to produce an enriched air containing 50 volume % O2. The ratio of moles of air to O2 used is
Q 5: Methanol is produced by the reaction of CO with H2
CO+H_2\rightarrow CH_3OHOnly 15 % of carbon monoxide entering the reactor is converted to methanol. The methanol formed is condensed and recovered completely. The unreacted CO and H2 are recycled back to the reactor. The feed will contain H2 and CO in the ratio of 2:1. For 3200 Kg/hr of methanol produced, calculate. (i) Kg mole/hr of fresh feed, (ii) Kg mole/hr of recycled gas. Mol. wt. of CH3OH = 32
Q 6: The Orsat analysis of a flue gas is CO2 12.7 %, O2 7.1 %, and N2 80.2 %. Determine the percent excess air used in the combustion. The nitrogen present in the flue gas is contributed by air only.
Q 7: Pure CO is mixed with 100 % excess air and burnt. Only 0 % of CO burns. The reactants are at 100° C and the products are at 300° C. Calculate the amount of heat added or removed per Kg mole of CO fed to the reactor. Data: Mean molal specific heats between 25 °C and T °C (given below) in KJ/Kg mole. °K are
Gas | T = 1000 C | T = 3000 C |
---|---|---|
CO | 29.22 | 30.61 |
CO2 | ——- | 4377 |
O2 | 29.64 | 30.99 |
N2 | 29.17 | 29.66 |
The standard heat of formation at 250 C in KJ/kg mole is -110524 for CO and -393514 for CO2.
Q 8: Bituminous coal with a calorific value of 20000 KJ/Kg is used for generating steam in a boiler how much coal has to be burnt to generate 1 MW of energy? The efficiency of combustion is 0.75. How much air is needed if 50 % excess air is to be used? Assume that coal contains 67 % carbon and 33 % ash.