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Design of an Ethylene Plant from Natural Gas Derived Feed

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No of baffles. Table 3: Insulation of HE 2 and the shell ... Number of baffles = 13, The insulation thickness = 79 mm, and. The shell thickness = 10 mm. ... – PowerPoint PPT presentation

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Title: Design of an Ethylene Plant from Natural Gas Derived Feed


1
United Arab Emirates University College of
Engineering Graduation Project 2
Design of an Ethylene Plant from Natural Gas
Derived Feed
Ismail Abdalla Al-Ali 199900293 Mohamed Saeed
Al-Ameri 199905057 Hassain Naje
199900270 Faculty Advisor Dr. Farid Benyahia
Coordinator Dr. Munjid Maraqa
2
Content of presentation
  • Introduction
  • PID HAZOP Study of Section of the Plant
  • Project Costing Economic Evaluation
  • Mechanical Design of a Selection of Major Process
    Equipment
  • Conclusion

3
Objective
  • To design, cost and evaluate safety and
    environmental impacts of an ethylene plant in the
    UAE.

4
Introduction
  • The work done in GP1
  • Ethylene marketing
  • Safety and environmental impact assessment
  • Process technologies of ethylene production
    (Licensed Petrochemical Processes)
  • and make a comparison between technologies
  • Process description and representation by a PFD
  • The plant site location
  • Preliminary cost
  • Completed material balance
  • Completed energy balance

5
  • The work done in GPII
  • Piping and instrumentation diagram (PID) and
    HAZOP study of section of the plant
  • Detail economic evaluation of the process
  • Mechanical design of a selection of major process
    equipment

6
PID HAZOP Study of Section of the Plant
  • The Piping and Instrument Diagram (PID) shows the
    engineering details of the equipment,
    instruments, piping, valves and fittings and
    their arrangement.
  • Instruments are provided to monitor the key
    process variable during plant operation.
  • The primary objective of the designer when
    specifying instrumentation and control schemes
    are
  • Safe plant operation
  • Production rate
  • Product quality
  • Cost

7
  • The Piping and Instrument Diagram (PID) as in
    Figure 1 without HAZAP study.
  • Hazards and operability studies (HAZOP) involves
    a systematic study of the process or parts of it.
  • It is applying special guide words to generate
    thought about the way deviations from the
    intended operating conditions can cause dangerous
    situations.

8
Example of HAZOP study
HAZOP for cracking section Table 1 HAZOP study
in S1 for flow deviation
9
  • The PID has been upgraded after the HAZOP study
    to improve the process safety as in Figure 2.

10
Project Cost and Economic Evaluation
  • Cost plays an active role for the engineering
    life.
  • The design engineer needs to be able to make
    quick, rough, cost estimates to decide between
    alternative designs and for the project
    evaluation.
  • Costing of the Project
  • Preliminary (approximate) estimates, accuracy
    typically 30 .
  • Authorization (Budgeting) estimates, accuracy
    typically 10-15 .
  • Detailed (Quotation) estimates, accuracy
    typically 5-10 .

11
Fixed Capital
  • It is the total cost of the plant ready for start
    up.
  • This cost doesn't return back when the project is
    finish and it paid one time.
  • It includes the cost of
  • Design and other engineering and construction
    supervision.
  • All items of equipment and their installation.
  • All piping, instrumentation and control systems.
  • Building and structure.
  • Auxiliary facilities, such as utilities, land and
    civil engineering work.

12
Working Capital
  • It is the additional investment needed
  • includes the cost of
  • Start-up.
  • Initial catalyst charges.
  • Raw materials and intermediates in the process.
  • Finish product inventories.
  • Funds to cover outstanding accounts from
    customers.
  • Most of the working capital is recovered by the
    end of the project.
  • The total investment needed for a project is the
    sum of the fixed and the working capital.

13
Step Counting Methods
The correlation of Timms, IChemE (1988) gives a
simple equation for gas phase processes.
  • C 8000 N Q0.615
  • C capital cost in US dollars
  • N number of functional units
  • Q plant capacity, tonne per year

14
C 8000 18 (600000)0.615 515,140,282 US
Dollars
This cost is valid for 1998 according to the
correlation shown above
Cost 2003 (Cost Index 2003)/ (Cost Index 1998)
(Cost 1998) (398) / (390)
(515,140,282) 525,707,262 US Dollars
Cost of the plant in 2004 496501303 1.02
536,221,407 US dollars
Cost of the plant in 2005 496501303 1.02
546,945,835 US dollars or approximately 547
million US Dollars
15
Total Investment
  • Investment is spread over 4 years
  • Total investment Year 1 Year 2 Year 3
    Year 4 546,945,835 US Dollars

16
Operating Cost
  • Fixed Operating Cost
  • For each year up to year 10
  • Operating cost 0.037 Capital cost
    20,236,996
  • From year 10 up to year 17
  • Operating cost 0.046 Capital cost
    25,159,508
  • From year 17 to year 30
  • Operating cost 0.055 Capital cost
    30,082,021
  • Variable Operating Cost
  • For each year up to year 17
  • Variable cost 17 /tone
  • From year 17 to year 30
  • Variable cost 22 /tone

17
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18
Rate of Return (ROR) and Discount Cash Flow (r)
Calculations
Where Cumulative net cash flow at end of the
project 6856.8 106 Life of the
project 30 year Original investment
546945835.2 ROR 41.79
The discount rate (r) 33.74
19
Mechanical Design of a Selection of Major Process
Equipment Economic
  • The chemical engineer is normally required to
    specify the main dimensions of the pieces of
    equipment.
  • The mechanical design is done to
  • Shell and tube heat exchanger
  • Column of DET
  • Column of DEE

20
Heat Exchanger
  • The transfer of heat to and from process fluids
    is an essential part of most chemical processes.
  • The shell and tube exchanger is far the most
    commonly used type of heat transfer equipment
    used in the chemical and allied industries.

21
Results of calculation for different tube
diameters
Table The mechanical design result of HE 2 at
different tube inside diameter (30, 25 and 16 mm).
22
Table 3 Insulation of HE 2 and the shell
thickness.
23
Figure Shell and Tube Heat Exchanger
2
24
Distillation Columns
  • The separation of liquid mixtures into their
    several components is one of the major processes
    of the chemical and petroleum industries, and
    distillation is the most widely used method of
    achieving this end.

25
The result of DEE calculations
Table Summary of the results for various plate
spacing
26
Figure DEE Column
27
The result of DET calculations
Table 5 The result of DET calculations
28
Figure DET Column
29
Conclusion
  • The HAZOP study was done to enhance the level of
    instrumentation in order to improve safety. This
    was comprehensively achieved by applying
    different guide words to process variable
    deviations like temperature, pressure and flow
    (No, Less and More).
  • The economic evaluation of the project was
    carried out. The plant capital cost was found to
    be approximately 547 million US Dollars.
  • The rate of return (ROR) was found to be 41.71
    and the discount cash flow (r) was 33.37 .
  • The project was found to be economically viable
    because ROR is larger than r. This means that the
    plant can be built and operated at a good profit.

30
  • Since our process was rather large, the main
    equipment considered for detailed mechanical
    design were heat exchanger number 2 (HE 2) in the
    cracking section, deethylenizer column (DET) and
    deethanizer column (DEE) in the purification
    section.
  • The design calculation of HE 2 showed that
  • Inside tube diameter 16 mm,
  • Shell diameter 3 m,
  • Ethane velocity 6.32 m/s,
  • Number of baffles 13,
  • The insulation thickness 79 mm, and
  • The shell thickness 10 mm.
  • The design calculation of DET column showed that
  • The diameter of column 2.50 m,
  • The height of column 56 m, and
  • The column shell thickness 4 mm.
  • The design calculation design of DEE showed that
    (at plate spacing 0.5 m)
  • The diameter of column 1.70 m,
  • The height 11.5 m,
  • The isolation 0.032 mm, and

31
Thank YouFor Listening
32
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33
The Diagram of Ethylene Process with PID
34
The Diagram of Ethylene Process with PID After
HAZOP Study
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