UAE University College of Engineering Training and Graduation Project Unit

1
UAE UniversityCollege of EngineeringTraining
and Graduation Project Unit
Prepared by ID Aisha
AlMehrezi 200002652 Fatima Al
Mazroui 200007010 Nada Emad Alsayed
200107266 Shareifa Ali Saeed
200105214 Faculty Advisor Dr.Muftah El-Naas
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Outline

• Background
• Problem Definition.
• Suggested Solutions.
• Solvay Process.
• Material Balance.
• Energy Balance.
• Equipment Selection, Specification and Design.
• Background
• Main Units
• Bubble Column Reactor.
• Filtration.
• CSTR Reactor.
• Dryer.
• Gas-Liquid Separator.
• Storage Tanks.
• Pumps Compressors.

• Safety and Loss Prevention.
• Hazards ( definition, types).
• HAZOP( definition, objective, work-sheet).
• Apply HAZOP Study on the process.
• P ID and Control System.
• Cost Estimations
• Preliminary evaluation of a chemical reaction.
• Capital Cost.
  
• Manufacturing Cost.
• Experimentation.
• Conclusions.

3
Background
4
Project Description

• Problem definition
• Reject brine is highly concentrated waste
  water.
• The four major desalination plants in the UAE
  produce huge amounts of reject brine ranging from
  (10-15) tons/s.
• Environmental Impact

5
Comparison among the different options according
to some factors
Evaporation ponds Deep-well injection Zero discharge Surface water discharge
Economical Yes - Low capital operating cost No -Expensive construction costs. No - High capital costs - Energy costs are significant Yes Reasonable cost but transportation costs are variable due to plant location
Suitable to UAE Yes Warm climate with high evaporation rates Yes land is available and geologic conditions are suitable Yes The technology can be applied Yes For coastal desalination plants
Safe Yes Proven environmentally safe Yes Proven environmentally safe Yes Reuse the brine concentrates without adding any chemicals to avoid any pollution. Yes Environmentally acceptable alternative
Practical Yes Simple Technology Yes Simple to design operate No -Mechanically complex -Large energy demands Yes For coastal desalination plants
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Solvay Process

• Definition.
• Advantages.
• Objectives
• Treat reject brine instead of dumping it to the
  sea.
• Utilize carbon dioxide in the process instead of
  releasing it to the atmosphere.
• Recover ammonia during the process and reuse it.

7
Process Kinetics
8
Material and Energy Balances

• The material and energy balance calculations
  were built
• based on the following data

Given Data Values Units
Conversion in the First Reactor 0.8  
Conversion in the Second Reactor 0.8  
Volumetric rate of reject brine 50 ton/hr
Concentration of reject brine 8 wt
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Material Balance Summary
10
Energy Balance Summary
Bubble Reactor Q cooling(kW) 380
CSTR Q heating(kW) 16
Pumps Power Units
1 0.19 kW
2 0.37 kW
3 0.17 kW
4 0.34 kW
Compressors Power Units
1 491 kW
2 11.8 kW
11

• Equipment Selection, Specification and Design

12
Background

• Process Design
• is the synthesis of the complete process as an
  assembly of the main units, each carrying out a
  specific process operation.
• Selecting and Sizing of the equipments was done
  on the following units
• Bubble Reactor.
• Filtration Unit
• Dryer.
• CSTR Reactor.
• Gas-Liquid Separator.

13
Materials of Construction

• Materials
• Carbon Steel.
• Stainless Steel.
• Titanium.
• Nickel.
• Selected Material
• Carbon Steel.
• Advantages
• Low Cost.
• Easy to fabricate.
• Resists most alkaline environments.

14

• Design of The Main Units

15
Bubble Column Reactor
v 5 m3/hr
Residence Time 2 hr
Volume of Bubbling Reactor 1 10 m3
D 2 m
L 4 m
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Filtration Unit

• Types of filtration Units.
• Rotary Drum Filters.
• Disc Filters.
• Belt Filter
• Centrifugal Filters.
• Selected Type
• Rotary Drum Filter.
• Advantages of using Rotary Drum Filter
• Economical operation can be obtained.
• Widely used in chemical industry were calcium
  carbonate and ammonium sulfate crystals are
  filtered on large scale

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Rotary Drum Filter
Filter Design (Rotary Drum)
Mass flow rate 5848 kg/hr
Liquid Density 1103 kg/m3
Volumetric flow rate 5 m3/hr
Velocity 3 m/hr
Area 2 m2
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CSTR Design
Total volumetric flow rate 4.5 m3/hr
Residence Time (hr) 1.6 hr
Volume of Reactor 7.1 m3
D 1.5 m
L 3. m
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Gas-Liquid Separator
Ut 2.8 m/s
Us 0.4 m/s
Vv 0.09 m3/s
Dv 0.5 m
hv 3 m
20
Rotary Dryer
D 2 m
Qt 131 kW
G 6707 kg/m2h
?T 328 K
L 3 m
21
Storage Tanks

• Types of Storage Tanks
• Horizontal tanks on concrete supports.
• Vertical tanks on concrete pads.
• Tanks with floating roofs.

Example Storage Tank 1
Storage Tank 1 (Brine)
Design Parameter Values Units
Mass flow rate 5285 kg/hr
Liquid Density 1057 kg/m3
Volumetric flow rate 5 m3/hr
Residence Time 6 hr
Volume 0.85 m3
22
Pumps

• Pumps fall into three categories
• positive displacement
• kinetic (centrifugal)
• jet (eductor).
• Selected Type
• Centrifugal Pump.
• Advantages of Centrifugal Pump.
• Design Parameter
• Pumping Power.

23
Pump Design
Pump1    
  Values Unit
Mass flow rate of liquid 5285 kg/hr
Liquid density 1057 kg/m3
inlet Pressure 1 bar
outlet Pressure 2 bar
Delta P 1 bar
Efficiency 0.75  
Volumetric Flow rate 5 m3/hr
pumping power 0.186 kW
24
Compressors

• Types of compressors
• Reciprocating
• Axial-flow
• Centrifugal
• Selected Type
• Reciprocating Compressor.
• Advantages
• Able to perform efficiently at low pressure.
• Design Parameter
• Compressing Power.

25
Compressor no.1 Transfer Ammonia from Gas-Liquid
Separator to Bubble Column Reactor
Compressor 1    
  Values Unit
Ammonia flow rate 226.16 kg/hr
density of ammonia 0.68 kg/m3
inlet Pressure 1.00 bar
outlet Pressure 3.00 bar
Delta P 2.00 bar
Gas Constant (R ) 8.31 J/K.mol
Inlet Temperature 298.15 K
n 1.40 -
n-1/n 0.29 -
compressing power 11.80 kW
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• Safety and Loss Prevention

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Process Safety

• To insure Safety in chemical processing the
  following
• factors should be taken into
  consideration
• 1. Identification and assessment of hazards.
• 2. Control of hazards (containment of flammable,
  toxic materials)
• 3. Control of the process (to avoid dangerous
  situations).
• 4. Limit the loss of life, damage to equipment
  and environment by
• proper Design, pressure relief, plant layout
  and provision of fire
• fighting.

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Hazards

• Definition
• The potential to cause harm.
• Types of hazard
• Toxicity (poisonous chemicals).
• Flammability (measure of the extent to which a
• material will support combustion).
• Explosions
• Pressure
• Sources of ignition.
• High Temperature
• Noise.

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HAZOP Study

• A Hazard and Operability (HAZOP) study is a
• structured and systematic examination of a
• planned or existing process operation in
  order
• to identify and evaluate problems.

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HAZOP Terms

• Guide-words
• (NO, LESS, MORE).
• Deviation
• (flow, pressure, and temperature).
• Possible causes
• (equipment and instrumental failure).
• Consequences
• (problems results).
• Actions
• (problems solutions)

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HAZOP Procedure

• Divide the system into sections.
• 2. Choose a unit.
• 3. Describe the design intent.
• 4. Select a process parameter.
• 5. Apply a guide word.
• 6. Determine causes.
• 7. Evaluate Consequences/problems.
• 8. Recommend action.

32
HAZOP Study on (CSTR)
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Before HAZOP Study
34
(No Transcript)
35
After HAZOP Study
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Process Flow Diagram after HAZOP Study
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Cost Estimation
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Cost Estimation

• Costing is a specialized subject and is based on
  empirical methods.
• Cost evaluation is important because plants are
  built to make profit.
• Costing is performed to
• -Decide between alternative designs
• -Estimate the investment required.
• -Estimate the cost of production.

39
Process profitability

• It is evaluated by estimating
• Economical feasibility
• Technical feasibility

40
Economical Feasibility
Economic potentialMarket value of products-cost
of reactants
Ammonia 225 /tonne
Sodium bicarbonate 298 /tonne
Sodium carbonate 238 /tonne
Sodium chloride 99 /tonne
Calcium oxide  79 /tonne
Calcium chloride 182 /tonne
Ammonium Chloride 2380 /tonne
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Economical Feasibility

1. NaCl (aq) NH3 (g) CO2 (g) H2O (l) ? NaHCO3
   (s) NH4Cl (aq)
2. 2NH4Cl (aq) Ca(OH)2 (s)? CaCl2 (l) 2NH3 (g)
   H2O (l)

1st Reaction 2221 /tonne
2nd Reaction 2052 /tonne
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Technical feasibility
?G reaction?H reaction-T?S reaction By Using
HSC Program ?G reaction
1st Reaction -6.165 Kcal
2nd Reaction -7.934 Kcal
?G reactionlt0 so the process is spontaneous So,
it is technically feasible
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Capital Cost Estimation

• Definition The cost involved in construction of
  a new plant or modifications added to an existed
  one.
• Costs employed in the evaluation
• Materials purchased cost
• The property cost
• Materials delivery
• Construction
• Driveway
• Hooking up utilities

44
Capital Cost Factors
Factors Considered Sub - Sections
Direct Expenses Equipments Installation Materials Required Labors
Indirect Expenses Freight, Taxes and Insurance. Construction Overhead Contractor Engineering
Contingency Fee Contingency. Contractor Fee.
Auxiliaries Site Development Utilities Off-sites Auxiliary Buildings
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Equipment Module Costing Technique

• Accepted as the best in order of preliminary cost
  estimations.
• Base conditions are carbon steel as a material of
  construction and 1 atm pressure.
• Deviations from the basis
• The specific equipment type.
• Specific material of construction (MOC).
• Specific system pressure.

46
Equations Involved

• Where
• K1, K2 and K3 are correlation coefficients for
  each piece of equipment.
• A Capacity or size parameter.
• C1, C2 and C3 are correlation coefficients for
  each piece of equipment.
• B1, B2 are correlation coefficients for each
  piece of equipment.
• P is the operating pressure.

47
Capital cost Estimation
Example 1 Pump1
Pumps
Type Centrifugal
A Power
k1 3.58
k2 0.32
k3 0.03
C1 0.168
C2 0.348
C3 0.484
B1 1.80
B2 1.51
MOC SS
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Pump Bare Module Cost
Pressure (bar) 1.00
Power (kW) 0.186
log Fp 0.17
Fp 1.47
FM 2.4
Log Cp 3.36
Cp in 1996 2292
Cp () in 2006 2969
CBM() in 2006 21197
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Example 2 Bubbling Column Reactor
Height (m) 4.00
Diameter (m) 2.00
Pressure (bar) 3.00
MOC Cs
Orientation Vertical
k1 4.05
k2 0.46
k3 0.16
B1 2.50
B2 1.72
FM 1.00
Fp 1.00
Cost index _at_ 1996 382.00
Cost index _at_ 2006 495.00
log Cp 4
Cp in 1996 24509
Cp () in 2006 31759.04
CBM() in 2006 134023.14
50

• Capital Cost Summary

• Capital Cost for the whole plant.

CP () total 735127
CTM () 2853452
CGR () 3699815
51
Manufacturing Cost
52
Manufacturing Cost

• It is the cost of producing the products.
• It is needed to judge the viability of the
  project and select between alternative processing
  method.
• Factors affecting the cost of manufacturing (COM)
  can be divided in to
• Direct Manufacturing Costs
• Fixed manufacturing Costs
• General Expenses

53
Direct Manufacturing Costs

• They represent operating expenses that
• vary with production rate.
• In general the direct manufacturing costs
• include the cost of
• Raw Materials.
• Operating Labor
• Utilities.
• Maintenance and repair

54
Fixed Manufacturing Costs

• These cost do not vary with production rate.
• They includes
• Property taxes
• Insurance
• Depreciation

55
General Expenses

• Cost associated with management level
• and administrative activities.
• They include
• Administration Costs.
• Distribution and selling costs.
• Research and development.

56
The equation used to evaluate the COM
57
COM Estimation
58
COM Estimation

• The Cost Items for each of the three categories
  are added together to provide the total cost for
  each category.
• The total manufacturing cost can be obtained
  by adding these three cost categories together
  and solving for the total manufacturing cost
  (COM).

59
COM Estimation

• The cost of manufacturing (COM) can be
  determined when the following costs are known or
  can be or can be estimated
• Fixed Capital Investment (FCI) CTM or CGR.
• Cost of Operating Labor (COL).
• Cost of Utilities (CUT).
• Cost of Waste Treatment (CWT)
• Cost of Raw Materials (CRM).

60

• Cost of operating labor

• The following calculations were applied to get
  the average yearly wage of operators.

61
Labor Costs Results
Equipment Type Number of Equipments Operators per Equipment per shift Operators per shift
Process Equipment      
       
Compressors 2 0.15 0.6
Pumps 4 0 0
Reactors 2 0.5 1
Vessels 6 0 0
TOTAL 1.6
Operating Labor 7.2
Operating Labor (rounded) 8
Labor Cost /yr 374400
62

• Utility Costs

Utility Cost /Common Unit units(/common unit)
Electrical Substation 0.06 /kWh
Air Supply 4.7 /100m3

• Example

Compressor1
Compressing Power (kW) 11.80
Cost of Electric Substation 0.06
Yearly Cost (/yr) 5892
63

• Costs of Raw Materials

Chemical Cost(/kg) Amount (kg/hr) Cost(/yr)
NH3 0.28 930 2167048
CaO 0.09 612 458375
CO2 0.13 1201 1299313
TOTAL 0.50 274 3924738

• Fixed Capital Investment (FCI)CGR
• The fixed capital cost was already calculated
  previously and was found to be equal to
  3699815/yr

64
Manufacturing Costs Results

• Yearly Costs and Stream Factors

65
Experimentations
66
1. First Reaction
NH3 H2O NaClCO2 NaHCO3 NH4Cl
67
Procedure of First Reaction
Video 1
68
Experimental Results

• Percentage of Na in each sample

Sample ppm of Na (mg/L) of Na
Original Simulated Brine 1689.33 10.13
Ammoniated Brine 1391.00 8.60
Filtrated Brine 1028.00 6.06
Precipitate solution 602.67 0.03
69
2. Second Reaction
2NH4Cl (aq) CaO (s)? CaCl2 (l) 2NH3 (g) H2O
(l)
70
Procedure of the 2nd reaction
Video 2
71
Experimental calculations
Amount of NH3 (g) Amount of NH3 (mol) V(ml)-Titrated with NaOH Time (min)
0 0 11.5 0
0.085 0.01 10.5 5
0.093 0.011 10.4 7
0.111 0.013 10.2 10
0.426 0.05 6.5 15
0.792 0.093 2.2 20
0.374 0.044 7.1 35
0.630 0.074 4.1 40
0.042 0.005 11 55
0.042 0.005 11 57
0.085 0.01 10.5 60
0.212 0.025 9 67
0.298 0.035 8 69
0.723 0.085 3 80
0.809 0.095 2 83
0.936 0.11 0.5 85
72
Experimental Results
73
Conclusions

• Experiments were carried out to characterize
  the reject brine and determine the needed
  properties.
• Results from these experiments, materials and
  energy balances as well as information related to
  materials of construction were all used to
  design the main process units.
• Hazard identification and control to reduce
  potential risks and assure safe process was
  achieved by performing a HAZOP study.
• A comprehensive cost estimation and
  environmental impact study were carried out for
  the process.

74
References
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of spent brines or Osmotic solutions", Journal of
food engineering 49(2001), 237-246. 2.A.Ibrahim
and J. El Yakubi, "Chemical conversion of salt
concentrations from desalination plants",
Desalination 139(2001), 287-295. 3.
http//en.wikipedia.org/wiki/Solvay_process. 4.War
ren L. McCabe, Julian C. Smith and Peter
Harriott"Unit Operations of .Chemical
Engineering", Fifth Edition, 1993 5.J.M. Coulson
and J.F. Richardson "Chemical Engineering",
R.K.Sinnott Volume 3, Third Edition,
1999 6..http//www.engineeringtoolbox.com/pid-pip
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w.nmsu.edu/safety/programs/lab_safety/app15_msds_
gloss.htm 8.http//pie.che.ufl.edu/guides/hazop/ 9
.http//ed.icheme.org/costchem.html 10.Ulrich,
G.D., A guide to Chemical Engineering Process
Design and Economics, Wiley, New York,
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ed.,McGraw-Hill, New York, 1990. 12.Valle-Riestra
J. F., Project Evaluation in the Chemical Process
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