14-Plant Design-Ans Key-Master File
14-Plant Design-Ans Key-Master File
14-Plant Design-Ans Key-Master File
SOURCE QUESTION
MRII 1. This is the first step in plant and equipment design
2014 a) Feasibility study
b) Development of optimum economic design
c) Detailed engineering design
d) Costing
MRII 1. In a plant and equipment design, our role as chemical engineer are the following, except
2014 a) To design new plant and expansion lines
b) To modify existing lines and processes
c) To develop new technologies
d) To construct the plant and/ or equipment
MRII The following are parts of a feasibility study, except
2014 a) Market research
b) Technical feasibility
c) Financial statement
d) Economics
MRII A particular cost estimation for a particular product is enlisted below:
2014 Distribution and Marketing costs USD97,200
Direct Production costs USD 1,848,737.25
Fixed Charges USD 225,225.25
Plant Overhead Cost USD 575, 235.85
General Expenses USD 103,523.45
What is the total manufacturing cost?
a) USD 2,699,198.35
b) USD 2,699,148.35
c) USD 2,649,198.35
d) USD 2,649,198.85
MRII Based from the preceding problem, what is the Total Product Cost?
2014 a) USD 2,349,921.80
b) USD 2,849,921.80
c) USD 2,349,971.80
d) USD 2,899,921.80
MRII Based from the preceding problem, if the production rate is 20,625, what is the break even point selling price?
2014 a) USD 113.94
b) USD 138.18
c) USD 123.22
d) USD 140.60
MRII Based from the preceding problem, if the market price is USD 200, what is the break even point selling volume?
2014 a) 11,749.61
b) 14,249.61
c) 11,249.61
d) 14,499.61
MRII It describes the general sequence of materials, unit operations and processes involved, equipment and operating parameters
2014 a) qualitative flow diagram
b) quantitative flow diagram
c) combined – detailed flow diagram
d) detailed-estimate flow diagram
MRII 1. This is the most important part of a feasibility study in the eyes of an investor
2014 a) Market study c) Economic study
b) Technical study d) Financial study
MRII 2. Which is not included in the market study?
2014 a) present and future demands c) competition
b) buying habits d) location
Indian 1. The total capital investment for a chemical plant is USD1.5 million. Working capital is USD 180,000. The plant can produce
Reviewe 28205 lb of a product per day during a 360 days/yr operating time. The selling price ($/ton) of the product required to give
r a turn over ratio of 1 is
a) 245 b) 250 c) 260 d) 275
SOL’N:
Products produced days 1 ton
year
=( 28205lb ) 360
yr ( )( 2000lbm )
PLANT DESIGN
Products produced
=5076.9tons / yr
year
Fixed capital = Total capital – working capital
Fixed capital = $(1,500,000-180,000) = $1,320,000
Indian A newly installed piece of equipment has a value of Php50,000. Its useful life is estimated to be 10 years and its salvage value is
reviewer Php8,000. Depreciation will be charged as a cost by making equal yearly payments, first payment being made at the end of the
first year. The depreciation fund will be accumulated at an annual interest rate of 8¼ %. The yearly depreciation cost (Php) under
these conditions is
a) 2357 b) 2865 c) 3286 d) 4229
Money borrowed today is to be paid in 6 equal payments at the end of 6 quarters. If the interest is 12%
compounded quarterly. How much was initially borrowed if quarterly payment is Php2000.
a) Php10,200.56 b) Php10,382.90 c) Php10,586.99 d) Php10,834.38
2. The total capital investment for a chemical plant is $1.2 million. If the plant can produce an average of 7500 kg
of final product per day during a 365 day per year, what is the selling price in dollars per kilogram of the
product? Assuming working capital is 15 to 20% of the total capital investment.
a) $0.36 b) $1.00 c) $2.76 d) no answer
SOL’N:
Products produced kg days kg
year
= 7500
day (
365
yr )(
=2,737,500
yr )
Fixed capital = Total capital - working capital
A 100 m3 tank costs $3040 in 2004. Estimate the current cost of a 300 m 3 tank, if the exponent for a 300 m3 tank
is 0.9.
PLANT DESIGN
1. A 100 m3 tank costs $3040 in 1992. Estimate the 2004 cost of a 300 m3 tank, if the exponent for a 300 m3 tank is 0.9.
a) $1350 b) $6852 c) $7009 d) $9745
0.9
300 m3 1124.7
Cost 300 m3 tank=$ 3040 ( 100 m3 )( 943.1)=$ 9,744.55
A reactor A with a negligible scrap value costs P1.1 million and will have a useful life of 6 years. Another reactor B with equivalent
capacity is priced at P1.8 million but with a useful life of 10 years and a scrap value of P200,000. Assuming an effective compound
interest rate of 6 percent per year and that the replacement cost of each reactor is the same as that of the original reactor.
PLANT DESIGN
The cost of equipment is P500,000 and the cost of installation is P30,000. If the salvage value is 10% of the cost
of equipment at the end of 5 years, determine the book value at the end of the fourth year. Use straight line
method.
A parent on the day the child is born wishes to determine what lump sum would have to be paid into an account
bearing interest of 5% compounded annually, in order to withdraw Php20,000 each on the child’s 18 th, 19th, 20th and
21st birthdays. How much is the lump sum amount?
1. The initial cost of a machine is $20,000. Its salvage value after 10 years of useful life is $4000. Interest rate is 10% and
the annual maintenance cost is $1000. The annual cost ($) of the machine is most nearly.
a) 3004 b) 3618 c) 4004 d) 4506
SLU A 250 ft2 shell and tube heat exchanger was purchased for Php135,000 in 1989 when the index value was 830. Estimate the cost
of a 150 ft2 shell and tube heat exchanger in 2001 when the index value is 964 and the appropriate cost capacity factor is 0.6.
a) Php 115, 410
PLANT DESIGN
SLU A solvent extraction operation is carried out continuously in a plate column with gravity flow. The unit is operated 24 h/day. A
feed rate of 1500 ft3/day must be handled 300 days per year. The allowable velocity per square foot of cross sectional tower area
is 40 ft3 of combined solvent and charge per hour. The annual fixed costs for the installation can be predicted from the following
equation:
C F =8800 F2sf −51000 F sf + 110,000
P/year, where Fsf is cubic feet of solvent per cubic foot of feed. Operating and other variable costs depend on the amount of
solvent that must be recovered, and these costs are Php 0.04 for each cubic foot of solvent passing through the tower. The tower
diameter that should be used for optimum conditions of minimum total cost per year is _________.
a) 2.4 ft
PLANT DESIGN
SLU The design formulas below are used to find the allowable pressure of a thick-walled pressure vessel if the thickness, t is known:
2
Z−1 R+t
P=SE ( Z +1 ) with
( )
Z=
R
A seamless forging with an 8 ½” ID is 2.25” thick and is made of code material with an allowable stress of 17500 lbf/in 2. The
allowable pressure for this cylinder is _________.
a) 7020 psi
PLANT DESIGN
SLU A tank contains 50,000 kg of 20% oleum (20 kg SO 3 dissolved in 80 kg of pure H2SO4). The kilograms of water that must be added
to the tank to give 93.2 weight percent sulfuric acid, commonlu called oil of vitriol is _________.
a) 6060 kg
SLU At a plant produces sulfuric acid by the contact process, a large storage tank currently holds 100,000 kg of 20% oleum. The tank
has a total capacity when filled of 130,000 kg. If water is added to the tank to fill it just to its capacity, the weight percent
sulfuric acid in the final mixture in the tank is ________.
a) 80.4%
a) 279 Btu/ft3
SLU One metric ton of clay was used in the making of ceramic batch. If this represents 30% of the whole batch and the analysis of
the other raw materials in the batch is 35% feldspar and 35% quartz and efficiency of manufacture is 80%, the pieces of ceramic
products made weighing 0.091 kg each is _________.
a) 28,080
PLANT DESIGN
SLU For thick spheres, a y factor is used to determine thickness, t, if P is known. The equations are:
2 ( SE+ P )
t=R ( y 1 /3−1 ) and y=
2 SE−P
Where: t=minimum required thickness of sphere (inch); R=inside diameter of sphere (inch); S=allowable stress (lbf/in 2); E=joint
efficiency (%); P=allowable pressure. Assuming S=14,000 lbf/in 2, P=3000 psi and E=100%, the thickness of a sphere with a 10 inch
inside diameter to be used with a 3000 psi allowable pressure is _______.
a) 9/16 inch
SLU Determine the allowable pressure for a vessel with the following original design details, but which now has a minimum thickness of
0.40 inch.
Corrosion allowance = 1/8 inch
Nominal thickness = 0.688 inch
Outside diameter = 24 inch
Carbon steel allowable stress = 15,000 psi
Design pressure = 500 psi
Longitudinal double welded butt joint with full radiography
An ellipsoidal head attached to each end of the shell with a single welded butt joint with a backing strip, and only spot-
radiographed. Use the formula below for a cylindrical shell to calculate the pressure for the longitudinal welded or seamless
SEt
joints. P=
R+0.6 t
a) 510 psi
SLU Water is treated with an ion-exchange resin which must be regenerated. A large tank is available at no cost for storing softened
water to smooth any variations in demand and to supply water while the resin is being regenerated at negligible time. Demand
averages 2.3 m3/h for all the hours in a year. The time, t, in hours that the resin can be used before it must be regenerated is
PLANT DESIGN
160V
given by: t=
F
where V is the volume of the resin in m3 and F is the flow rate of the water in m3/h. Fixed costs are Php 9000/m3 for the resin
and equipment for a 5-year economic life. Regeneration costs vary as the 0.8 power of the volume of the resin and are Php 55 for
a 1 m3 unit. The total cost for a 1000 m3 of softened water is ________.
a) Php430
SLU An evaporator’s scales and tests show that the steam condensed in the heating tubes varies with time according to the
relationship: S = A (50 – 0.05t), t<1000
where A is the condensation rate in kg.h, A is the heating area in m 2 and t is the evaporating time in hours since the last clean –
out. There will be 0.9 kg of water evaporated per kg of steam condensed. The cost for the evaporators is Php2100/m 2 heating
area and is written off over a 10 year period. The allocable labor cost is Php15/h of operation. Each cleaning costs Php2500. The
water to be evaporated per year is 4.5 x 106 kg and the operating time is not to exceed 6000 h/yr. The optimum heating area to
PLANT DESIGN
be installed is ________.
a) 113 m2
PLANT DESIGN
SLU Lubricating oil is to be treated continuously in a tower using a selective solvent to remove naphthenic material. The parameter R is
defined as R = bbl solvent used/bbl oil treated and the treatment cost, without recovery of the solvent, in pesos per year is given
by 18,600 R2 – 111,000R + 217,000. It costs Php 0.40 to separate each barrel of solvent circulated through the tower and 300
bbl/day of oil will be processed for 320 days per year. The most economical value of R to be used in bbl solvent per bbl oil is ____.
a) 1.92
PLANT DESIGN
SLU A water solution of molasses contains 10% by weight sucrose (C 12H22O11). The CO2 formed in the reaction can be considered as
having a negligible solubility. The weight percent of ethyl alcohol in the solution after 90% of the sucrose has been converted to
ethyl alcohol by fermentation and the last 10% of the sugar can be assumed unchanged is ___________.
a) 5.1%
PLANT DESIGN
SLU For a two stage adiabatic compressor where the gas is cooled to the inlet gas temperature between stages, the theoretical work is
given by
k−1 k−1
k P1 V 1 P2 P
W= (
k−1 )[( )
P1
k
( )
−2+ 3
P2
k
]
where: k=Cp/Cv; P1= inlet pressure; P2=intermediate stage pressure; P3=outlet pressure; V1=inlet volume. If P1=1 atm and P3=4 atm,
the optimum intermediatepressure P2 so that the work is a minimum is _______.
a) 1 atm b) 2 atm c) 3 atm d) no answer
SLU A sphere with a 30 ft inside diameter stores gas at a maximum pressure of 75 psi at 125 0F. The sphere is made of a low-alloy
steel plate, a double welded butt joint with full radiography are used and the material has a code-allowable stress of 17,500 psi.
The thickness of the spherical vessel with no corrosion allowance is _______.
a) ¼ inch b) ½ inch c) ¾ inch d) 1 inch
PLANT DESIGN
SLU The thick cylinder equations below are used whenever the pressure exceeds 0.385SE or when the thickness of the cylindrical shell
exceeds half the radius:
SE+ P 1
Z=
SE−P
and (
t=R Z 2 −1 )
where: t=thickness, inch; R= inside radius (inch); S=allowable stress (psi); E = welded joint efficiency (%); P= allowable working
pressure (psi). A seamless cylinder with 10 inch inside diameter is made of SA-182 grade F321 stainless steel, to be operated at
10000F and 3000 psi. The allowable stress for this material is 14,000 psi at the designated temperature. Without corrosion
allowance, the thickness of the cylinder is _________.
a) 5/4 inches
SLU A large spherical tank contains gas at a pressure of 500 psi. The tank is 60 ft in diameter and is constructed of high tensile
strength steel having a yield stress in tension of 80 ksi. The minimum thickness of the wall of the tank if a factor of safety of 3.2
with respect to yielding is required is _________.
a) 375 inches
SLU A scuba tank is being designed for an internal pressure of 1800 psi with a factor of safety of 2.0 with respect to yielding. The
yield stress of the steel is 42,000 psi in tension and 20,000 psi in shear. If the diameter of the tank is 6 inches, the required wall
thickness is _______.
a) 0.27 inch
SLU Water is to be cooled by air in a certain type of forced draft cooling tower at a rate of 7,000 gph for 7400 hr/year. The height
PLANT DESIGN
of the transfer unit maybe considered constant at 15 ft and the number of transfer units varies approximately with the gas
velocity as follows for a fixed water velocity of 600 lb/h-ft 2 based on the empty tower and a fixed air inlet temperature.
2000
Number of transfer units=
G 12
g
12
where G g is the air velocity in lb/h-ft2 based on the empty tower. If the cost of the tower installed is Php 0.8/ft 3 for 8 years’
C D =6 G12 −6
service and direct costs vary as g x 10 , pesos/hour. The optimum mass velocity is _______.
a) 110.7 lb/hr-ft 2
102. Tops Corporation’s gross margin is 45% of sales. Operating expenses such as sales and administration are 15% of sales. Tops is in a 40%
tax bracket. What percent of sales is their profit after taxes?
a) 5% b) 18% c) 24% d) 30%
PLANT DESIGN
103. An electric replacement pump is being considered for purchase. It is capable of providing 200 hp. The pertinent data are as follows: cost
= $3200, electric efficiency = 0.85, maintenance cost per year = $50 and life expectancy is 14 years. The pump is used for 400 hours per
year and the cost of electricity is $0.04 per kW-h. Assuming the pump will have no salvage value and using straight line depreciation,
what will be the monthly cost?
a) $238.20 b) $667.60 c) $234.60 d) $647.60