Question 81. In petroleum refining, catalytic reforming is used to convert

Question 82. A thermocouple having a linear relationship between 0oC and 350oC shows an emf of zero and 30.5 mV, respectively at these two temperatures. If the cold junction temperature is shifted from 0oC to 30oC, then the emf correction (in mV) is

Question 83. An equimolar mixture of A and B (A being more volatile) is flash distilled continuously at a feed rate of 100 kmol/h, such that the liquid product contains 40 mol % of A. If the relative volatility is 6, then the vapor product, in kmol/h, is

Question 84. The elementary reversible exothermic gas-phase reaction A + 3B 2C, is to be conducted in a non-isothermal, non-adiabatic plug flow reactor. The maximum allowable reactor temperature is Tmax To minimize the total reactor volume, the variation of reactor temperature ( T ) with axial distance from the inlet ( ≈ ) should be

Question 85. The characteristic equation for a system is s3 + 9s2 + 26s + 12(2 + Kc) = 0. Using the Routh test, the value of Kc that will keep the system on the verge of instability is

Question 86. A reverse osmosis unit treats feed water (F) containing fluoride and its output consists of a permeate stream (P) and a reject stream (R). Let CF, CP and CR denote the fluoride concentrations in the feed, permeate, and reject streams, respectively. Under steady state conditions, the volumetric flow rate of the reject is 60 % of the volumetric flow rate of the inlet stream, and CF = 2 mg/L and CP = 0.1 mg/L. The value of CR in mg/L, up to one digit after the decimal point, is _________

Question 87. The purchase cost of a heat exchanger of 20 m2 area was Rs. 500000 in 2006. What will be the estimated cost (in Rs. to the nearest integer) of a similar heat exchanger of 50 m2 area in the year 2013? Assume the six-tenths factor rule for scaling and the cost index for 2006 as 430.2. The projected cost index for the year 2013 is 512.6. _________

Question 88. Liquid reactant A decomposes as follows A --> R rR = k1C2A k1 = 0.5 m3/mol-s A --> S rS = k2CA k2 = 1 s-1 An aqueous feed of composition CA0 = 30 mol/m3, CR0 = 2 mol/m3 and CS0 = 1 mol/m3 enters a CSTR in which the above reactions occur. Assume isothermal and steady state conditions.
If the conversion of A is 80 %, the concentration of R in the exit stream in mol/m3, to the nearest integer, is _________

Question 89. A plant manufactures compressors at the rate of N units/day. The daily fixed charges are Rs. 20000 and the variable cost per compressor is Rs. 500 + 0.2 N1.3. The selling price per compressor is Rs. 1000. The number of compressors to be manufactured, to the nearest integer, in order to maximize the daily profit is ___________

Question 90. A reverse osmosis unit treats feed water (F) containing fluoride and its output consists of a permeate stream (P) and a reject stream (R). Let CF, CP and CR denote the fluoride concentrations in the feed, permeate, and reject streams, respectively. Under steady state conditions, the volumetric flow rate of the reject is 60 % of the volumetric flow rate of the inlet stream, and CF = 2 mg/L and CP = 0.1 mg/L. A fraction f of the feed is bypassed and mixed with the permeate to obtain treated water having a fluoride concentration of 1 mg/L. Here also the flow rate of the reject stream is 60% of the flow rate entering the reverse osmosis unit (after the bypass). The value of f , up to 2 digits after the decimal point, is __________