Title: United Arab Emirates University
1 United Arab
Emirates University
College of Engineering Training and
Graduation Projects Unit Graduation
Project II
Liquefied Natural Gas
Advisor Dr. Marcelo Castier Done by Basma
Ali 200211743 Fatima Rashid 200212000 Latifa
Obaid 200203237 Sheikh AL thahry 200202742
2Outline
- Back ground Gp1
- Introduction to Liquefied Natural Gas project
- Main objectives challenges
- Process Descriptions of the co production plant
- Equipments sizing Design parameters
- HAZOP study Process Modifications
- Economic evaluation
- Site layout location
- Conclusions
3Background GPI
- Process Selection
- Material Balance Calculation.
- Energy Balance Calculation.
4Process of Liquefaction of Natural Gas
Co-production.
Hybrid cycle.
Double Mixed Refrigerant
5HYSIS simulation
Compression Loop
6HYSIS simulation
Compression Loop
7Project description
- Project objective
- The main technical challenge of this project is
to cool natural gas into very - low temperature (approximately -163 0C), what
requires several interlinked refrigeration
cycles. - Raw Feed Materials Specifications
- Tools and Methods
Conditions Stream Temperature (oC) Pressure (kPa) Mass flow rate (kg/sec)
Natural gas 31 8860 129.515
8Project challenge
- Setup the process model in a commercial simulator
(HYSYS) and obtain numerical convergence. - Design a unusual distillation column with
multiple feeds and products and, more
importantly, with a liquid recycle structure at
the top of the column that does not occur via a
conventional condenser. - Design a liquid expander, which exists in the
plant to recover mechanical work from liquid
expansion.
9Process Description
10(No Transcript)
11Introduction to NGL
12Important definitions
- Natural gas is a mixture of hydrocarbon gases and
acid gases with varying molecules and amount of
impurities. - NGL is removal of certain components, such as
dust, helium, water, and heavy hydrocarbons and
then condensed into a liquid at close to
atmospheric pressure.
13Equipment sizing Design parameters
14Introduction to equipment design
- Design mean is to formulate a plan for devise
designed. - Important of equipment design-
- Checking new process designs
- Providing equipment size and performance
estimates - Helping to troubleshoot problems with operating
systems - Verifying the reasonableness of results of
computer calculations and simulations - Obtaining approximate costs for process units
14
15Equipment Design
15
16High-Pressure Phase Separator
- From heuristics of separator-
- Rule 1 ? Vertical Vessel Rule 1 ? L/D between
2.5 and 5 with optimum at 3.0 Rule 3 ? liquid
hold-up time is 5 min based on ½ volume of vessel
Rule 4 ? Gas velocity u (m/s) is given by -
- where k 0.0305 for vessels without mesh
entrainers - Data provided from HYSYS-Vapor flow, Liquid
flow, ?v and ?l
16
17Heat Exchanger Design
- Heat exchanger is device that is used to transfer
thermal energy from one fluid to another without
mixing the two fluids. - Main parameter of designing heat exchanger
- determining its type, area and duty.
- The type of heat exchangers in the LNG plant are
shell and tube heat exchangers.
17
18Expander Design
- Liquid expanders offer the potential to improve
process efficiency by recovering otherwise unused
energy. -
- Type of Liquid Expander
- Cryogenic Liquid Expander
- Joule Thompson (JT) Valve
- Hydraulic turbine.
- Flashing liquid expander.
18
19Expander Design
- Assumptions
- Adiabatic.
- Reversible.
- ?S 0, isentropic process.
- Ideal gas.
- Equations
- dH T ds V dP
- ? H V dP.
- Rackett equation Vsat Vc Zc (1-Tr) 0.2857
19
20Compressor
- Mechanical device that increases the pressure of
a gas by reducing its volume. Compression of a
gas naturally increases its temperature.
20
21Compressors design
- Determination of
- Type of compressor.
- V. m./?
- CR Pout/Pin lt3
- Poptimum Pout vPin/Pout
- Efficiency.
- Power actual power.
- R.A.P n. Z. R. T. (Pout/Pin)a - 1)/a,
- a Cp/Cv, A (k-1)k
- Actual power R.A.P / ?
- Outlet temperature.
21
2222
23Determination of compressibility factor
Tr T/Tc Pr P/Pc
23
24Valves design
- A device that regulates the flow of substances
like gases, fluidized solids, slurries or
liquids, by opening or closing. - Valves applications
- Used for safety purposes.
- Used for controlling applications.
24
25Valves design parameter
- a) The process requirements (pressure and flow)
downstream. - b) The service (regular flow line,
intermittent, blow-down, depressurizing). - c) The variations in the flow and pressure with
time. - d) Fluid characteristics (composition, solids,
Newtonian or non-Newtonian). - e) Phase behavior (single phase, two phase,
water contain). - f) The suitable diameter for the suitable pipe
with stand - the range of velocity between 5 10 ft.
25
26Distillation Column Design
- Distillation is a process in which a liquid or
vapor mixture of two or more substances is
separated into its component. - Determination of relative volatility
- Raults Law
26
27Cont Relative Volatility
- Minimum number of stages by using Fenske equation
- Nmin
- Log (XLD/XHD)(XHW/XLW) /Log (aavg.)
- Actual Reflux Ratio
- (R-Rmin)/(R1)
27
28Diameter Height of tower
?vap ( avg.Mw P) / (R/T)
Volume flow rate (Top flow Mwav.)/(vap.?
3600)
Velocity (1.35)/(top ?) 0.5
Diameter (m) ((4Volume flow rate)/(pv))0.5
Refer to recommended tray table Hmin (NAS
1)plate spacing Hmax (NAS 1)plate
spacing(13)
28
29HAZOP study and Process modification
30Definition of HAZOP
-
- An analysis of the hazards which could occur at
step in the process, and a description and
implementation of the measures to be taken for
their control. - Invented by the BCI "British chemical industry"
in the United Kingdom. - Officially adopted in 1974 after flixborough
explosion. - This chemical plant explosion killed twenty eight
people and injured scores of others - the public living nearby
- Lack of a systematic review of the qualified
personnel.
31Benefits of using HAZOP techniques
- easy to learn.
- can be easily adapted to almost all industrial
operations - No special level of academic qualification is
required. - The HAZOP Study is an opportunity to correct
these before such changes become too expensive,
or 'impossible' to accomplish. - HAZOP methodology is perhaps the most widely used
aid to loss prevention.
32Procedure setup
33HAZOP Analysis
3. Subdivide the system or activity and develop
deviations
2. Define the problems of interest for the
analysis
1. Define the system or activity
2.0 Define the problems of interest for the
analysis
1.0 Define the system or activity
5. Use the results in decision making
4. Conduct HAZOP reviews
34Process Modification
- Studying the special concern of these conditions
are important to provide conditions that allow
effective process performance.
35Special Concern Area of Equipments
Conditions Type of Equipments
High temperature (Tgt250OC) or pressure (Pgt10 bar)Low temperature (Tlt40OC) or pressure (Plt1 bar) Separators
Pout/Pin gt 3High Temperature inlet gas Compressors
?TIngt100oC Heat exchangers
Large ?P across valve Valves
Streams of greatly differing temperatures mixStreams of greatly differing composition mix Mixers
36Special Concern areas
- Distillation Column
- There are a special concern.
- Heat Exchanger
- ? TIn 105.9 oC -30 oC
- 75.9 oC lt100 oC
37Economic evaluation
38Introduction to equipments cost
- Cost Estimation
- Cost estimation models are mathematical
algorithms or parametric equations used to
determine the costs of plant. - The results of the models are typically necessary
to measure approval to proceed, and are factored
into business plans, budgets, and other financial
planning and tracking mechanisms.
39Total module and Grass root cost
- Total module cost can be evaluated from
- And Grass root cost can be evaluated from
40Cost Estimation for Coolers
40
4141
42Estimation Costs
42
43Cost estimation for distillation column
- Cost equations for tower and trays.
- Volume p D2 L / 4
- Area for trays V / L
44Raw material Cost
- The cost of raw materials can be estimated by
using the current price listed in such
publications as the Chemical Market Reporter
(CMR).
45Labor Operating Cost
The technique used to estimate operating labor
requirements is based on data obtained from five
chemical companies and correlated by Alkayat and
Gerrard.
45
46Equipment Type Number of Equipment Nnp
Exchangers 9 9
Compressors 4 4
Expanders 3 3
Tower 1 1
Vessel 1 -
Total 17
46
47Utilities Cost (CuT)
- Specific difficulties emerge when estimating the
cost of fuel like electricity, stream and thermal
fluid. - Costs of utility streams required by process
includes - Fuel gas, oil and coal.
- Electric power.
- Stream.
- Cooling water.
- Process water.
- Boiler feed water.
- Instrument air.
- Inert gas.
- Refrigeration.
48Changes in Fuel prices
49Compression between coal and NG
50Plant Layout
- It is necessary to make a preliminary study on
the layout of the plant equipments. -
51Layout depending factor
- Main rooms as control room and offices should sit
away from areas that have high accident risk and
upstream of the current winds. - Reactors, boilers, etc., Should build up
- away from the chemical storage tanks.
- Storage tanks should be easy access and choice on
whether all tanks (of raw materials and products)
should be located together or dispersed
throughout the site
52- Availability of plant requirement.
- Minimizing plant piping systems.
- Suitable access to equipment that usual require
maintenance or repair and keep a space between
equbments. - Access to the plant in the case of an accident.
- Availability of source of cooling place for
equipments need cooling water close.
53The aim of minimizing the layout of plant
equipment
- avoid damage to persons and property due to fire
or explosion. - decrease Maintenance costs.
- reduce number of worker in the plant.
- decrease operating costs.
- reduce construction costs.
- Reduce cost of expansion or modifications on
plant.
54 Piping and Instrumental Diagram (PID) Designs
- The piping and instrumentation diagram (PID)
provides information need by engineers to begin
planning for the construction of the plant. - Mechanical engineers and civil engineers will
design and install pieces of equipment. - Instrument engineers will specify, install and
check control system. - Piping engineers will develop plant layout and
elevation drawings. - Project engineers will develop plant and
construction schedules.
55Conventions in constructing PD diagram
- For equipments, show every piece including spare
units, parallel units and summary details of each
unit. - For piping, include all lines including drains,
sample connections and specify size, schedule,
materials of construction and insulation. - For instruments, identify indicators, recorders,
controllers and show instrument line. - For utilities, identify entrance utilities, exist
utilities and exist to waste treatment
facilities.
5656
57Conclusion
- Total Module Cost and Grass Roots Cost
- Cost of operating labor (COL)
- Utility costs (CUT)
- Total utilities cost 4.685107
/yr - Raw materials costs (CRM)
- Capital Cost of Manufacturing (COMd)
58Qatar Conference of LNG
Important Dates Full Paper Submission June 16,
2008 Paper Acceptance August 8, 2008
Final Submission August 24, 2008