Process Economics and Cost Estimation - Plant Design and Economics - Chemical Engineering Previous Year Questions

1

2008 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2008

For the case of single lump-sum capital expenditure of Rs. 10 crores which generates a constant annual cash flow of Rs. 2 crores in each subsequent year, the payback period (in years), if the scrap value of the capital outlay is zero is

A

10

B

20

C

1

D

5

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2

2008 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2008

The relation between capital rate of return ratio (CRR), net present value (NPV) and maximum cumulative expenditure (MCE) is

A

\(CRR = \frac{NPV}{MCE} \)

B

\(CRR = \frac{MCE}{NPV} \)

C

\(CRR = NPV \times MCE \)

D

\(CRR = \frac{MCE}{(NPV + MCE)} \)

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3

2009 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2009

The total fixed cost of a chemical plant is Rs. 10.0 lakhs; the internal rate of return is 15%, and the annual operating cost is Rs. 2.0 lakhs. The annualized cost of the plant (in lakhs of Rs.) is

A

1.8

B

2.6

C

3.5

D

4.3

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4

2009 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2009

A column costs Rs. 5.0 lakhs and has a useful life of 10 years. Using the double declining balance depreciation method, the book value of the unit at the end of five years (in lakhs of Rs.) is

A

1.21

B

1.31

C

1.64

D

2.05

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5

2010 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2010

A reactor needs to be lined with a corrosion resistant lining. One type of lining costs Rs. 5 lakhs, and is expected to last for 2 years. Another type of lining lasts for 3 years. If both choices have to be equally economical, with the effective interest rate being 18%, compounded annually, the price one should pay for the second type of lining is

A

Rs. 6.1 lakhs

B

Rs. 6.5 lakhs

C

Rs. 6.9 lakhs

D

Rs. 7.6 lakhs

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6

2010 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2010

A plant produces phenol. The variable cost in rupees per tonne of phenol is related to the plant capacity P (in tonnes/day) as 45,000 + 5P. The fixed charges are Rs. 10,00,000 per day. The selling price of phenol is Rs. 50,000 per tonne.
The optimal plant capacity (in tonnes per day) for minimum cost per tonne of phenol, is

A

101

B

141

C

283

D

422

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7

2010 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2010

The break-even capacity in tonnes per day, is

A

50

B

40

C

30

D

20

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8

2011 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2011

A process plant has a life of 7 years and its salvage value is 30 %. For what MINIMUM fixed-percentage factor will the depreciation amount for the second year, calculated by declining balance method be EQUAL to that calculated by the straight line depreciation method?

A

0.1

B

0.113

C

0.527

D

0.887

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9

2011 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2011

A continuous fractionator system is being designed. The following cost figures are estimated for a reflux ratio of 1.4.

Fixed cost including all accessories (Rs.) for			Operating cost (Rs./year) for
column	condenser	reboiler	condenser cooling water	reboiler heating steam
6 × 10⁶	2 × 10⁶	4 × 10⁶	8 × 10⁶	1 × 10⁶

The annualised fixed charge is 15 % of the fixed cost. The total annualised cost (in Rs.) is

A

10.8 × 10⁶

B

13.35 × 10⁶

C

15.9 × 10⁶

D

3.15 × 10⁶

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10

2011 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2011

The variable cost (V) of manufacturing a product varies according to the equation V= 4q, where q is the quantity produced. The fixed cost (F) of production of same product reduces with q according to the equation F = 100/q. How many units should be produced to minimize the total cost (V+F)?

A

5

B

4

C

7

D

6

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11

2012 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2012

A batch reactor produces \(1 \times 10^7\) kg of a product per year. The total batch time (in hours) of the reactor is \(k \sqrt{P_B}\), where \(P_B\) is the product per batch in kg and \(k = 1.0\) h/\(\sqrt{kg}\). The operating cost of the reactor is Rs. 200/h. The total annual fixed charges are Rs. \(340 \times P_B\) and the annual raw material cost is Rs. \(2 \times 10^6\). The optimum size (in kg) of each batch (adjusted to the nearest integer) is

A

748

B

873

C

953

D

1148

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12

2012 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2012

Heat integration is planned in a process plant at an investment Rs. \(2 \times 10^6\). This would result in a net energy savings of 20 GJ per year. If the nominal rate of interest is 15% and the plant life is 3 years, then the breakeven cost of energy, in Rs. per GJ (adjusted to the nearest hundred), is

A

33500

B

43800

C

54200

D

65400

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13

2012 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2012

The cost function for a product in a firm is given by \(5q^2\), where \(q\) is the amount of production. The firm can sell the product at a market price of ₹50 per unit. The number of units to be produced by the firm such that the profit is maximized is

A

5

B

10

C

15

D

25

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14

2013 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2013

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.

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15

2013 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2013

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 N^{1.3}. 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

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16

2014 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2014

A cash flow of Rs. 12,000 per year is received at the end of each year (uniform periodic payment) for 7 consecutive years. The rate of interest is 9% per year compounded annually. The present worth (in Rs.) of such cash flow at time zero is __________

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17

2014 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2014

A polymer plant with a production capacity of 10,000 tons per year has an overall yield of 70%, on mass basis (kg of product per kg of raw material). The raw material costs Rs. 50,000 per ton. A process modification is proposed to increase the overall yield to 75% with an investment of Rs. 12.5 crore. In how many years can the invested amount be recovered with the additional profit? __________

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18

2017 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2017

The cost of a new pump (including installation) is 24,000 Rupees. The pump has a useful life of 10 years. Its salvage value is 4000 Rupees. Assuming straight line depreciation, the book value of the pump at the end of 4th year, rounded to the nearest integer, is ______ Rupees.

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19

2018 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2018

The Annual Fixed Charges (AFC) and Annual Utilities Costs (AUC) of a distillation column being designed are expressed in terms of the reflux ratio (R) as
AFC (Rs. Lakh) = 641×R² – 1796×R +1287 +1/(R – 1.16)
AUC (Rs. Lakh) = 80 + 62.5×R
The reflux ratio (R_opt) for optimizing the total cost of the distillation column may be found by solving

A

1282×R_{opt} – 1796 – 1/(R_{opt} – 1.16)² = 0

B

62.5 + 1282×R_{opt} – 1796 – 1/(R_{opt} – 1.16)² = 0

C

80 + 62.5×R_{opt} + 641×R_{opt}² – 1796×R_{opt} + 1287 + 1/(R_{opt} – 1.16) = 0

D

80 + 62.5×R_{opt} – 641×R_{opt}² + 1796×R_{opt} – 1287 – 1/(R_{opt} – 1.16) = 0

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20

2018 · Chemical Engineering · Plant Design and Economics · Process Economics and Cost Estimation

Chemical Engineering (CH) 2018

In the year 2005, the cost of a shell and tube heat exchanger with 68 m^2 heat transfer area was Rs. 12.6 Lakh. Chemical Engineering Index for cost in 2005 was 509.4 and now the index is 575.4. Based on index of 0.6 for capacity scaling, the present cost (in Lakhs of rupees) of a similar heat exchanger having 100 m^2 heat transfer area is estimated to be

A

17.94

B

19.94

C

20.94

D

22.94

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