che604_644_4

CONFIDENTIAL EH/OCT 2010/CHE604/644

UNIVERSITI TEKNOLOGI MARA FINAL EXAMINATION

COURSE COURSE CODE EXAMINATION TIME

PLANT DESIGN AND ECONOMICS CHE604/644 OCTOBER 2010 3 HOURS

INSTRUCTIONS TO CANDIDATES

1. This question paper consists of five (5) questions. 2. Answer ALL questions in the Answer Booklet. Start each answer on a new page.

Do not bring any material into the examination room unless permission is given by the invigilator.

Please check to make sure that this examination pack consists of :

) the Question Paper i) a five - page Appendix 1 ) a three - page Appendix 2

iv) a one - page Appendix 3 v) an Answer Booklet - provided by the Faculty

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO This examination paper consists of 6 printed pages

Hak Cipta Universiti Teknologi MARA CONFIDENTIAL

CONFIDENTIAL 2 EH/OCT 2010/CHE604/644

QUESTION 1

a) For plant layout studies, computer-aided design (CAD) tools are being increasingly used. Explain five advantages of computer graphics modeling compared with physical models.

(10 marks)

b) Acetaldehyde is a colorless liquid with a pungent and fruity odor. It is primarily used as a chemical intermediate for the production of acetic acid, pyridine and butylenes glycol. Acetaldehyde is a volatile and flammable liquid that is miscible in water, alcohol, ether, benzene, gasoline, and other common organic solvents. The synthesis of acetaldehydes using the dehydrogenation process of ethanol occurs as the following reaction:

CH3CH2OH CH3CHO + H2 Acetaldehyde

2CH3CH2OH CH3COOC2H5 + 2H2 Ethyl acetate

2CH3CH2OH CH3(CH2)3OH+H20 Butanol

CH3CH2OH + H20 CH3COOH + 2H2 acetic acid

The conversion of ethanol is typically 60%. The yields for each reaction are approximately:

Acetaldehyde 92% Ethyl acetate 4% Butanol 2% Acetic acid 2%

i) For this process, generate a process concept diagram showing all the input and output chemicals.

(4 marks) ii) Develop one(1) alternative preliminary process flow diagram for this process.

(6 marks)

QUESTION 2

A substance has the following structure: CH3(CH2)4CH=CH-CH2-CH=CH(CH2)7COOH The boiling point was determined in the laboratory to be about 354C. Molar weights for carbon, hydrogen and oxygen are 12, 1 and 16 respectively.

a) Estimate the critical temperature, pressure and volume using Lydersen's method. Please refer to Appendix 1 as attached.

(14 marks)



b) Estimate the molar volume at its boiling temperature using group contributions given in Appendix 1.

(2 marks) c) Estimate the liquid heat capacity at 20C in kJ/kgC using Chueh and

Swanson's group contributions in Appendix 1. (4 marks)

QUESTION 3

a) There are several steps required to design a heat exchanger. Describe these steps in sequence.

(5 marks) b) The temperature-interval diagram for a process is shown in Figure 1

stream 4 5

mo

250

180 1 f

-ifin

140 ^

A

B

C

D

E

i h

4 I

kW/degC

280

230

210

160

140

120

50

-100

?kW Figure 1 Temperature interval diagram

i) Determine the missing values of mCp for stream 2 and 3, the missing Q values for temperature interval B, C, and E and the total heat duties, Q of all intervals.

(5 marks)



ii) Determine the minimum hot and cold utility loads for this process subject to a minimum approach temperature of 20C

(3 marks) iii) Determine the pinch temperature for this process. You may assume that there is

only one hot and one cold utility available. (2 marks)

iv) Design the network above the pinch based on the minimum number of exchangers needed for the minimum energy required above the pinch.

(5 marks)

QUESTION 4

a) AMR Sdn. Bhd, an oil and gas company wants to venture into ethylene dichloride (EDC) business. From the regional market survey done, it was found that there is a plant producing EDC in Merak, Indonesia. The production capacity of that plant is 350,000 metric tonne per annum (MTA) and the cost of it was USD378 million. As a costing engineer for AMR Sdn. Bhd., you are required to determine the range of cost estimations for a Class 2 and 4 as defined in Cost Estimate Classification System, AACE International Recommended Practice No. 17R-97.

(4 marks)

b) A petrochemical company hired you as a consultant to determine the size of a storage tank purchased in 1988. Many records regarding past purchase were lost because of fire in the management building in 1994. Luckily, a senior engineer of the company remembers that the tank was replaced every 10 years, and the sizes have changed due to plant capacity changes. The information given by the senior engineer is listed in Table 1. Estimate the original capacity of the tank.

Table 1 Details on previously purchased storage tanks

Year

1988 1998 2008

Tank Capacity (1000 m3)

? 105 85

Purchased Cost (RM)

123,900 158,550 159,250

(11 marks)

QUESTION 5

a) The annual variable production costs of an ethylene plant is RM980.000. This plant currently operates at 85% of full capacity. On top of that, the sum of annual fixed charges, overhead costs and general expenses is RM700.000 and considered not to change with the production rate. Total annual sales of the plant are RM1.96 million and the product sell for RM14.000 per tonne.



i) Briefly explain on gross profit, net profit and break-even point.

ii) Determine the break-even point.

iii) Determine the gross annual profit with depreciation.

(3 marks)

(8 marks)

(2 marks)

iv) Determine the net annual profit at 100% capacity if the income tax rate is 25% of gross profit.

(2 marks) b) A process to produce formalin from methanol has been designed. Cost data for this base

case are shown in Table 2 where all figures are in USD106 or USD106/year. For all parts of this problem, assume that the required before-tax return on investment is 15% per annum and the equipment life is considered to be 12 years.

i) Give your recommendation on the construction of this plant, whether the base case design is a profitable venture or not.

(4 marks) ii) There are two alternatives processes that require more expensive equipment, as

indicated in the table. Evaluate and give recommendations whether to invest or not.

(4 marks) iii) Suppose that there were another alternative requiring an additional USD2x106

capital investment. Determine the savings in operating costs required to make this as an attractive investment.

(2 marks)



Table 2 Details on projects considered

Capital investment Additional investment

Annual product revenue

Annual raw material costs

All other annual

operating costs

Base Case Design

11.9

-

11.1

3.16

0.299

Project B

-

1.02

11.1

3.16

0.206

Project C

. -

0.5

11.1

3.16

0.258

END OF QUESTION PAPER


CONFIDENTIAL APPENDIX 1 (1) EH/OCT 2010/CHE604/644

Lydersen's method for estimating the critical constants

n [0.567 + SAT - CEAT)2}

_M (0.34 + SAP)2 0.04+ EAV

where Tc = critical temperature, K. Pc = critical pressure, atm (1.0133 bar). Vc = molar volume at the critical conditions, nrrVkmol, Tb - normal boiling point, K. M = relative molecular mass. AT = critical temperature increments. AP = critical pressure increments. AF = molar volume increments.

Pc


CONFIDENTIAL APPENDIX 1(2) EH/OCT 2010/CHE604/644

AT AP AV AT AP AV

Non-ring increments

~

C H i 0.020 0.227 0.055

0.020 0.227 0.055

0.012 0.210 0.051

CH,

CH

C I

I = C H

0.00 0.210 0.041

0.018 0.198 0.045

0.018 0.198 0.045

=C

=C=

=CH

=C

H

0.0 0.198 0.036

0.0 0.198 0.036

0.005 0.153 0.036*

0.005 0.153 0.036*

0 0 0

Ring increments C H ,

I CH

I I

C

0.013 0.184 0.0445

0.012 0.192 0.046

-0.007* 0.154* 0.031*

= C H 0.011 0.154 0.037

0.011 0.154 0.036

0.011 0.154 0.036

Halogen increments F

a

Oxygen increments OH (alcohols) OH (phenols) O(non-ring) O(ring)

1 C = 0 (noiH-mg)

0.018

0.017

0.082

0.031

0.021

0.014*

0.040

0.224

0.320

0.06

-0.02*

0.16

0.12*

0.29

0.018

0.049

0.018*

0.030*

0.020

0.080*

0.060

Br

I

1 CO (ring)

| 1 HC0(abehyde) COOH (acid) COO(ester) = 0 (except for

combinations above)

0.010 0.50* 0.070*

0.012 0.83* 0.095*

0.033* 0.2* 0.050*

0.048 0.33 0.073

0.085 0.4* 0.080

0.047 0.47 0.080

0.02* 0.12* 0.011*

Nitrogen increments

~~

m2 0.031 0.095 0.028

NH (non-ring) I

NH(ring) I

N(non-ring)

0.031 0.135 0.037*

0.024* 0.09* 0.027*

0.014 0.17 0.042*

I N(ring) CN

NO,

0.007* 0.013* 0.032*

0.060* 0.36* 0.080*

0.055* 0.42* 0.078*



Molecular volumes

Air 0.0299 Br2 0.0532 Cl2 0.0484 CO 0.0307

C 0 2 COS H7 H 2 0

0.0340 0.0515 0.0143 0.0189

H2S I2 N2 NHi

0.0329 0.0715 0.0312 0.0258

NO N 2 0 O2 SO2

0.0236 0.0364 0.0256 0.0448

Atomic volumes

As 0.0305 Bi 0.0480 Br 0.0270 C 0.0148 Cr 0.0274

F Ge H Hg 1

0.0087 0.0345 0.0037 0.0190 0.037

P Pb S Sb Si

0.0270 0.0480 0.0256 0.0342 0.0320

Sn Ti V Zn

0.0423 0.0357 0.0320 0.0204

CI, terminal, as in RC1 medial, as in RCHC1R

Nitrogen, double-bonded triply bonded, as in nitriles in primary amines, RNfl h in secondary amines, R2NH in tertiary amines, R3N

Oxygen, except as noted below in methyl esters in methyl ethers

0.0216 0.0246 0.0156 0.0162 0.0105 0.012 0.0108

0.0074 0.0091 0.0099

in higher esters, ethers in acids in union with S, P, Is three-membered ring four-membered ring five-membered ring

I

six-membered ring as in benzene

Naphthal<

cyclohexane, pyridine

sne ring Anthracene ring

0.0110 0.0120 0.0083

-0.0060 -0.0085 -0.0115

' 1

-0.0150

-0.0300 -0.0475



Group Value Group Value O

Alkane 60.71 CH3 CH2

I CH-

I C

I

=CHj I

= C H

= C -

C=SH

I CH=

Olefin

Alkyne

In a ring

C = or c I

CH2 Oxygen

-O

,c=o \ / co

I H O II

COH

36.84 30.40 20.93

7.37

21.77

21.35

15.91

24.70 24.70

18.42

12.14

22.19 25.96

35.17

53.00

53.00

C O CHjOH

1 CHOH

| 1 COH

1 OH ON0 2

CI (first or Halogen

second on a carbon) CI (third or fourth on a carbon) Br

F

1

H 1

H N

H

1 N

1 N=(inarin C = N

S H

Nitrogen

*>

Sulphur

Hydrogen H (for formic acid, formates,

hydrogen cyanide, etc.)

73.27

76.20

111.37

44.80 119.32

36.01 25.12 37.68 16.75 36.01

58.62

43.96

31.40

18.84 58.70

44.80 33.49

14.65

79.97

Add 18.84 for any carbon group which fulfils the following criterion: a carbon group which is joined by a single bond to a carbon group connected by a double or triple bond with a third carbon group. In some cases a carbon group fulfils the above criterion in more ways than one; 18.84 should be added each time the group fulfils the criterion. Exceptions to the above 18.84 rule:

1. No such extra 18.84 additions for CH3 groups. 2. For a - C H 2 - group fulfilling the 18.84 addition criterion add 10.47 instead of 18.84. However, when

the - C H j - group fulfils the addition criterion in more ways than one, the addition should be 10.47 the first time and 18.84 for each subsequent addition.

3. No such extra addition for any carbon group in a ring.



Group Value Group Value

Alkane 60.71 CH3

C H 2

I C H -

_J_ T

= C H j I

= C H

= l_

C S H

I CH =

I I C== or c -

I

CHj

Olefin

Alkyne

In a ring

Oxygen -O-

\

C0 I

H O II

C O H

36.84 30.40

20.93

7.37

21.77

21.35

15.91

24.70 24.70

18.42

C 0 CHjOH

1 CHOH

| 1 COH

1 OH ON0 2

Halogen CI (first or second on a carbon) CI (third or fourth on a carbon) Br

F

I

Nitrogen H 1

H N

H

73.27

76.20

111.37

44.80 119.32

36.01 25.12 37.68 16.75 36.01

58.62

12.14 -N 43.96

31.40 22.19 25.96

35.17

53.00

53.00

79.97

"

N = ( i n a ring) C = N

Sulphur SH

Hydrogen H (for formic acid, formates,

hydrogen cyanide, etc.)

18.84 58.70

44.80 33.49

14.65

Add 18.84 for any carbon group which fulfils the following criterion: a carbon group which is joined by a single bond to a carbon group connected by a double or triple bond with a third carbon group. In some cases a carbon group fulfils the above criterion in more ways than one; 18.84 should be added each time the group fulfils the criterion. Exceptions to the above 18.84 rule:

1. No such extra 18.84 additions for -CH3 groups. 2. For a -CH2- group fulfilling the 18.84 addition criterion add 10.47 instead of 18.84. However, when

the -CH2- group fulfils the addition criterion in more ways than one, the addition should be 10.47 the first time and 18.84 for each subsequent addition.

3. No such extra addition for any carbon group in a ring.



Class 1 estimate: +6% to -4% accurate

= KAan

k - / V

c

Class of

Level of Project

Definttfen (as % of

Complete Estimate Definition)

Typical Purpose

of Estfinate

Expected Accuracy Preparation

Range Effort Methodology {+/- Range (Relative to (Estimating Relative to Best lowest Cost

Method) Index of 1} Index of 1)

Class 3 10%ta4Q%

GassS 0%io2% Screening or Stochastic or !Fawib3ity Jucigment

Gass* l%toiS% Concept Study Primarily or Feasibility Stochastic

Budget, Meted but Authorization, Pftaarily

or Control Stochastic Control or Primarily

Bid/Tender Deterministic & to 100% Check Estimate Detenriinistic

or Bid/Tender

Oass2 30%tOAf?a

a-

4 to 20

3 to 12

2fe>6

l l o 3

1

I

2to4

3 to 10

Sto20

loioaoo

Psa&cte Ave^ Moi^ gantown, WV; http;//vvww,aac^,rg)


CONFIDENTIAL APPENDIX 2(2) EH/OCT 2010/CHE604/644 Chemical Engineering Plant cost Index (CEPCI)

Annual Index

1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

318.4 323.8 342.5 355.4 357.6 361.3 358.2 359.2 368.1 381.1 381.7 386.5 389.5 390.6 394.1 394.3 395.6 402.0 444.2 468.2 499.6 525.4 575.4



CE Index Equipment

Heat exchangers and tanks

Process machinery

Pipe, valves & fittings

Process Instruments

Pumps & compressors

Electrical equipment

Structural supports & misc.

Construction labor Buildings Engineering & supervision

Oct. 09 Preliminary

527.9 623.6

567.0

605.7

768.9

409.8

896.3

464.2

636.5

331.4 495.4 344.6

Sep. 09 Final 525.7 621.5

563.4

604.0

768.3

409.7

895.9

464.7

632.5

327.5 493.2 345.4

Oct. 08 Final 592.2 720.0

711.7

664.7

864.0

439.0

893.0

471.9

771.8

326:2 522.8 351.3


CONFIDENTIAL APPENDIX 3 EH/OCT 2010/CHE604/644

9 j SJ coj

>" = Sj caj dj

NPV = -FCI + CF (P/A. i.n)

INPV = -PC * YS(pfAJrn)

Conversion Symbol Common Name E*|* No. Formula CF/P, i, w) Saisgle Payment Compound Amount

Factor (P/F, t, n) Single Payriveat Present Worth factor

A fo F {F/4, iy > Uoiforan Series Composted Amount Factor, Future Worth of Annult/

P to A fAtf>, i,#> Gajntal Recovery Facto?

AfcoF fP/4,, * jtf Umfonn Series FrssetitWorJliFarfor, Present Worth of Afawity

(9.5)

(9.6)

(9,11)

(9.12)

{9.13}

(9M)

tt + *)fl 1

(1 + 0" (1 * i T " I

i

sft + if a + ty-i a + ir-i

iff 4- if

che604_644_4

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