LNG Plant / QGX Model

Prepared By : Eng. Eyad Hirzallah

What is LNG ??

• LNG: Liquefied Natural Gas

• The main item in LNG is Methane

• Methane CH4

• Symbol C1

• Physical Phase Liquid

• Temperature -162 Cº

• Pressure 1.06 Bar

What is the function of LNG plant?

Raw Material LNG Plant LNG Major Product

Minor Products1-Condensate2- Propane C3H8 (C3)3- Butane C4H10 (C4)4- Sulfur 5- Helium (optional)6-Others

Wastes 1- Treated waste water 2- Acid gas 3- CO24- Heat

LNG Plant – QGX Model – Train 4

Raw Material(3 physical phases)Total Flow : 1668 Ton / hTemperature: 28 CºPressure: 80 bar

QGX

Train 4

LNG(1 physical phase)Total Flow: 963 Ton / hTemperature: -162 CºPressure: 1.1 barPhysical phase: liquid 1-C1 93.30%2-C2 5.95%3-N2 0.75%

Vapor(Flow :1419 Ton /h)1- C1 81.29 %2- C2 4.65%3- C3 1.70%4-iC4 0.33%5-nC4 0.52%6-iC5 0.17%7-nC5 0.15%8-C6+ 0.24%9-H2O 0.07%10-H2S 1.94%11-CO2 3.64%12-He 0.05%13-N2 5.20%14- S. C. 0.03%15- Aro. 0.02%

Liquid( Flow :254 Ton /h)1- C1 27.17 %2- C2 5.42%3- C3 4.94%4-iC4 1.85%5-nC4 3.78%6-iC5 2.41%7-nC5 2.57%8-C6+ 41.90%9-H2O 0.06% 10-H2S 3.23%11-CO2 2.66%12-He 0.01%13-N2 0.72%14-S.C. 0.59%15- Aro. 2.69%

Water(Flow :13 Ton /h)

1-H2O 99.78%2-H2S 0.13%3-CO2 0.09%

Notes

C6+:n-Hexane, n-Heptane, n-Octane, n-Nonane, n-Decan, n-C11, n-C12, m-Cyclopentane, Cyclohexane and m-Cyclohexane

Aro. :Aromatics:Benzene, Toluene and O-Xylene

S.C. :Sulfur Compound:COS, m-Mercaptan, , e-Mercaptan, , p-Mercaptan , b-Mercaptan, Pentanethiol, Thiophene and C9+ Mercaptan.

The percentage of materials are in Mol.

Raw Material

Common Area

Process Area/Unit 2 Acid Gas Removal

Process Area/Unit 3 Dehydration

Process Area/Unit 4 NGL Recovery

Process Area/Unit 5 Gas Chilling & Liquidation

Process Area/Unit 8 N2 Rejection & He Recovery

Off Plot Area/Unit 71 LNG Storage & Loading

Water & Liquid

Acid Gas & CO2

Water Vapor & S.C Aro. & Heavy Metals

Hydrocarbons Heavier than Ethane

N2 & He

LNG Plant – QGX Model – Train 4The Steps Needed To Get LNG Out from the Raw Material

Common AreaA) Slug Catcher Area: Segregating the three physical phases apart (Vapor, Liquid and Water).B) Inlet Facilities Area: Clearing out any droops of liquid or water from vapor.C) Inlet Facilities Area: Extracting from liquid all its content of Methane and add it to the main stream of

vapor.

Process Area ( Unit 2 –Acid Gas Removal)A) Taking out H2S and Co2 from the mean stream of vapor.

Process Area (Unit 3 –Dehydration / Mercury Removal)A) Taking out water vapor (H2O), Sulfur Compound and Aromatics from the main stream of vapor.

Process Area (Unit 4 – NGL Recovery)A) Taking out the maximum quantity of all the hydrocarbon elements which are heavier than Ethane – C3 and above - from the main stream of vapor.

Process Area (Unit 5 – Gas Chilling & Liquidation)A) Liquefying the main stream of vapor into liquid.

Process Area (Unit 8 – N2 Rejection & HE Recovery)A) Taking out the maximum quantity of Nitrogen (N2) and Helium (He) from the main stream of liquid.

Common Area

A) Slug Catcher Area: Segregating the three physical phases apart (Vapor, Liquid and Water).

B) Inlet Facilities Area: Clearing out any droops of liquid or water from vapor.

C) Inlet Facilities Area: Extracting from liquid all its content of Methane and add it to the main stream of vapor.

Common Area

Raw Material(3 physical phases)Total Flow : 1668 Ton / hTemperature: 28 CºPressure: 80 bar

Common

Vapor(Flow :1419 Ton /h)1- C1 81.29 %2- C2 4.65%3- C3 1.70%4-iC4 0.33%5-nC4 0.52%6-iC5 0.17%7-nC5 0.15%8-C6+ 0.24%9-H2O 0.07%10-H2S 1.94%11-CO2 3.64%12-He 0.05%13-N2 5.20%14- S. C. 0.03%15- Aro. 0.02%

Liquid ( Flow :254 Ton /h)1- C1 27.17 %2- C2 5.42%3- C3 4.94%4-iC4 1.85%5-nC4 3.78%6-iC5 2.41%7-nC5 2.57%8-C6+ 41.90%9-H2O 0.06% 10-H2S 3.23%11-CO2 2.66%12-He 0.01%13-N2 0.72%14-S.C. 0.59%15- Aro. 2.69%

Water(Flow :13 Ton /h)

1-H2O 99.78%2-H2S 0.13%3-CO2 0.09%

Sour Gas(1 physical phase)Flow: 1464 Ton / hTemperature: 45 CºPressure: 72 bar Physical phase: Vapor

1- C1 80.72 %2- C2 4.80%3- C3 1.89%4-iC4 0.40%5-nC4 0.61%6-iC5 0.18%7-nC5 0.15%8-C6+ 0.23%9-H2O 0.07%10-H2S 2.04%11-CO2 3.68%12-He 0.05% 13-N2 5.11%14- S.C 0.03%15- Aro. 0.02%

Vapor

Liquid

Liquid

Common Area

Raw MaterialSlug Catcher

20-X3102Inlet Separator20-V3109A/B

Vapor + Liquid + Water

Vapor + Drops of Liquid & Water

Product Gas Ko Drum20-V3104

Feed Gas Condensate Exchanger20-E3104A-D

Feed Gas Super Heater20-E3110A/B

Feed Gas Metering Skid20-Y3101

Sour Gas

Vapor

Vapor

Vapor

Vapor

Vapor

Slug Catcher Condensate Filters20-S3101A/B

Pre flash Drum20-V3101

LiquidWater

Liquid

Liquid

Water

Liquid

Vapor

Condensate Stripper FeedProduct Exchanger

20-E3107A/B

Off Gas Compressor(2-Stage)

20-K3101A/B

Condensate Stripper20-C3101A/B

Anti Hydrate Heater20 - E3106A/B

Vapor

Common AreaSlug Catcher Area / Slug Catcher /20-X3102

A) Segregating the three physical phases apart (Vapor, Liquid and Water)

Basic Principle

The basic principle used to segregate vapor from liquid from water is by using the difference in density

The density of water is higher than liquid, and the density of liquid is higher than the vapor.

The material with lower density will float above the material with higher density.

In slug catcher the vapor will be separated from the liquid and water in the first step, and in the second step liquid and water will be separated apart.

Slug CatcherArea

Raw MaterialFeed pipe to QGX

UG/ AGRaw Material

Feed pipe

Inlet of Raw Material to

Slug Catcher

Vapor Outlet

Liquid & Water Outlet

UG/ AGRaw Material

Feed pipe

Inlet of Raw Material toSlug Catcher

Vapor Outlet

Liquid & Water Outlet

Inlet of Raw Material toSlug Catcher

Vapor Outlet

Liquid Outlet

Water Outlet

Common AreaInlet Facilities Area /Inlet Separator / 20-V3109A/B

B) Clearing out any droops of liquid or water from vapor.

Basic Principle

The basic principle used to clear out any droops of liquid or water from vapor is by reducing their dynamic energy, and therefore it will fall down by gravityeffect.

This can be done by forcing the droops to hit a solid barrier which is located inside the separator, and during this process, the barrier absorbs all the dynamic energy stored in the droops, and then the droops will fall down and separated from the main stream of vapor.

Inlet Facilities Area

Inlet Separator20-V3109A/B

Inlet Separator20-V3109A/B

INLET FACILITYSouth-West Corner

Inlet of Vapor +drops of Liquid & Water

Outlet of Vapor

Outlet of Liquid & Water

Manhole

Common AreaInlet Facilities Area /Condensate Stripper /20 – C 3101A/B

C) Extracting from liquid all its content of Methane and add it to the main stream of vapor.

Basic Principle

The basic principle used to extract Methane from the Liquid is by increasing the temperature of the liquid.

The solubility of any gas into liquid increases with the reduction of liquid temperature, and decreases with the increase of the liquid temperature.

By increasing the liquid temperature, all the gases contained in liquid will be forced to get out.

Condensate Stripper20 – C3101A/B

INLET FACILITYNorth-West Corner

Condensate Stripper20 – C 3101A/B

Outlet of Vapor

Inlet of Liquid

Outlet of Liquid

Process AreaUnit 2 Acid Gas Removal

A) Taking out H2S and CO2 and any traces of COS from the main stream of vapor.

Unit 2Sour Gas

(1 physical phase)Flow: 1464 Ton / hTemperature: 45 CºPressure: 72 bar Physical phase: Vapor

1- C1 80.72 %2- C2 4.80%3- C3 1.89%4-iC4 0.40%5-nC4 0.61%6-iC5 0.18%7-nC5 0.15%8-C6+ 0.23%9-H2O 0.07%10-H2S 2.04%11-CO2 3.68%12-He 0.05% 13-N2 5.11%14- S.C 0.03%15- Aro. 0.02%

Unit 2 Acid Gas Removal

Sweet Gas(1 physical phase)Flow: 1291 Ton / hTemperature: 50 CºPressure: 67.2 bar Physical phase: Vapor

1- C1 85.69 %2- C2 5.01%3- C3 2.00%4-iC4 0.42%5-nC4 0.64%6-iC5 0.19%7-nC5 0.16%8-C6+ 0.26%9-H2O 0.17%10-H2S 0.0002%11-CO2 0.001%12-He 0.05%13-N2 5.11%14- S.C 0.03%15- Aro. 0.02%

H2S&

CO2&

COS

Process AreaUnit 2 Acid Gas Removal

A) Taking out H2S and Co2 and any traces of COS from the main stream of vapor.

Basic Principle

The basic principle used to extract H2S and CO2 and any traces of COS from the main stream of vapor is by exposing the main stream of vapor to a special chemical solvent ( methyl-di-ethanol-amine) ( MDEA ), which has very high solubility ratio towards H2S, CO2 and COS, and very low solubility ratio towards all the other gases in the main Vapor.

In order to get H2S, CO2 and COS out of the solvent, the solvent is cycled through a regeneration cycle, the Rich Solvent (full of H2S, CO2 & COS) will enter the regeneration sector and come back as Lean Solvent ( Free of H2S, CO2 & COS).

Process AreaUnit 2 – Acid Gas Removal

Sour Gas

Filter Separator24-S0201

Feed Gas Per Heater24-E0204

AGR Absorber24-C0201

Sweet Gas

Any traces of water or liquid

Rich Solvent to Regeneration Cycle

Lean Solvent from Regeneration Cycle

AGR Absorber over head KO Drum24-V0201

Process Area / SouthT4 / Hot Section

AGR Absorber 24-C0201

PROCESS AREASouth West Corner

AGR Absorber 24-C0201

Sour Gas Inlet

Sweet Gas Outlet Lean Solvent Inlet

Rich Solvent Outlet

Process AreaUnit 3 –Dehydration / Mercury Removal

A) Taking out water vapor (H2O), Sulfur Compound and

Aromatics out from the main stream of vapor.

Unit 3 –Dehydration / Mercury Removal

Unit 3Sweet Gas

(1 physical phase)Flow: 1291 Ton / hTemperature: 50 CºPressure: 67.2 bar Physical phase: Vapor

1- C1 85.69 %2- C2 5.01%3- C3 2.00%4-iC4 0.42%5-nC4 0.64%6-iC5 0.19%7-nC5 0.16%8-C6+ 0.26%9-H2O 0.17%10-He 0.05%11-N2 5.11%12- S.C 0.03%13- Aro. 0.02%

H2O&

Sulfur compound

&Aromatics

Dry Gas(1 physical phase)Flow: 1282 Ton / hTemperature: 25 CºPressure: 64.5 bar Physical phase: Vapor

1- C1 85.85 %2- C2 5.06%3- C3 1.99%4-iC4 0.42%5-nC4 0.63%6-iC5 0.19%7-nC5 0.16%8-C6+ 0.21%9-H2O 0.00%10-He 0.05% 11-N2 5.45% 12- S.C 0.00%13- Aro. 0.00%

Process AreaUnit 3 –Dehydration / Mercury Removal

A) Taking out water vapor (H2O), Sulfur Compound and Aromatics out from the main stream of vapor.

Basic Principle

The basic principle used to extract H2O, Sulfur compound, and Aromatics, is by forcing the main stream of vapor to enter a vessel which is full of material called Molecular Sieve (Aluminosilicate Crystalline Polymers), this material is solid and it comes on the shape of granules, sand and pellets.

Molecular Sieve has high absorb rate for low concentration of H2O, Sulfur compound, Aromatics, Mercury and some other materials.

The dehydration unit has an operational cycle of five steps, Adsorption, Depressurizing, Heating, Cooling, Repressurizing, and then start new cycle with Adsorption

However the two functional steps in this cycle are Adsorption and Heating.

In Adsorption step the main stream of vapor will enter through the Molecular Sieve, all H2O, Sulfur compound, and Aromatics which are contained in the stream will be absorbed by Molecular Sieve.

Molecular Sieve has a maximum capacity, it must be cleaned from the absorbed material, and this is done in the Heating step.

In the Heating step the main stream of vapor will stop entering the vessel which contains Molecular Sieve, and hot fuel gas will enter the vessel from the opposite side of the main stream of vapor inlet.

The composition of fuel gas is 66% Methane C1 and 44% N2, the temperature is 288 Cº and the pressure is 35.8 bar.

The hot fuel gas will clean out all absorbed material contained in Molecular Sieve, which will enable the Molecular Sieve to absorb H2O, Sulfur compound, and Aromatics in the following Adsorption step.

In order to ensure a continuous flow of the main stream of vapor into the dehydration unit, there are six vessels in the unit, four of them are always in the Adsorption step.

Process AreaUnit 3 – Dehydration/Mercury Removal

Sweet Gas

Dehydration Molecular Sieve Effluent Filter 24-S0301A/B

Dehydration Feed Gas Water Pre Cooler 24-E0306

Dehydration Feed Gas Pre Cooler 24-E0301

Dehydration Feed Gas Ko Drum 24-C0201

Dehydration Molecular Sieve 24-V0301A~F

Mercury Removal Vessel 24-V0351A/B

Mercury Removal Effluent Filters 24-S0351A/B

Dry Gas

H2O + Sulfur compound Aromatics + Hot Fuel Gas

(Spent Regeneration Gas)

Hot Fuel Gas

Dehydration

Molecular

Sieve

Vessel

ValveClosed

ValveClosed

ValveOpen

ValveOpen

Sweet Gas

Dry Gas

Process AreaUnit 3 – Dehydration/Mercury Removal

Adsorption

Dehydration

Molecular

Sieve

Vessel

ValveClosed

ValveClosed

ValveOpen

ValveOpen

Spent Gas

Hot Fuel Gas

Process AreaUnit 3 – Dehydration/Mercury Removal

Heating

Dehydration Molecular Sieve24 – V0301A~F

PROCESS AREASouth West Corner

Dehydration Molecular Sieve24 – V0301A~F

Sweet Gas Inlet / Spent Gas Outlet

Dry Gas Outlet / Hot Fuel Gas Inlet0

Process AreaUnit 4 – NGL Recovery

A) Taking out the maximum quantity of all the hydrocarbon elements which are heavier than Ethane – C3 and above -from the main stream of vapor.

Unit 4 – NGL Recovery

Unit 4

C3+

Dry Gas(1 physical phase)Flow: 1282 Ton / hTemperature: 25 CºPressure: 64.5 bar Physical phase: Vapor

1- C1 85.85 %2- C2 5.06%3- C3 1.99%4-iC4 0.42%5-nC4 0.63%6-iC5 0.19%7-nC5 0.16%8-C6+ 0.21%9-He 0.05% 10-N2 5.45%

Natural Gas(1 physical phase)Flow: 1124 Ton / hTemperature: 36.5 CºPressure: 66.5 bar Physical phase: Vapor

1- C1 89.04 %2- C2 5.24%3- C3 0.01%4-iC4 0.00%5-nC4 0.00%6-iC5 0.00%7-nC5 0.00%8-C6+ 0.00%9-He 0.05% 10-N2 5.65%

Process Area Unit 4 – NGL Recovery

A) Taking out the maximum quantity of all the hydrocarbon

elements which are heavier than Ethane – C3 and above -from the main stream of vapor.

Basic Principle

The basic principle used to fraction a mixture of hydrocarbons each one apart is by using the difference in boiling point for each material, in our case the boiling points for the hydrocarbons in the Dry Gas are:

Ethane (C2): -88.6 Cº at 1 bar

Propane (C3): -42 Cº at 1 bar

Butane (C4): 4.6 Cº at 1 bar

So if the temperature of the dry gas reduced to a degree much less than-42 Cº, but higher than -88.6, almost all the propane and higher hydrocarbons will be liquefied, but the Ethane and Methane will still in their original vapor condition, and therefore it will be easy to segregate liquid from vapor by gravity.

The segregation of liquid from vapor take place in the De EthanizerColumn, where dry gas mixture ( Liquid & Vapor) will enter the De Ethanizer Column at a temperature of -79.3 Cº and presser of 31.1 bar.

Process AreaUnit 4 – NGL Recovery

Dry Gas

NGL Recovery Gas/Gas Exchanger 24-E0401

Expander Feed Separator 24-V0401

De Ethanizer Column 24-C0401

De Ethanizer Reflux Condenser 24-E0403

Lean Gas Re compressor 24-K0402

Lean Gas Re compressor Air after Cooler 24-E0405

Lean Gas Re compressor Water after Cooler 24-E0406

Natural Gas

NGL Recovery Compander (Turbine Side)24-K0401A~C

NGL Recovery Compander (Compressor Side)

24-K0401A~C

C3+

De Ethanizer Column24 – C0401

PROCESS AREASouth West Corner

De Ethanizer Column24 – C0401

Dry Gas Inlet

NG Outlet

C3+ Outlet

Process AreaUnit 5 – Gas Chilling & Liquidation

A) Liquefying the main stream of vapor into liquid.

Unit 5 – Gas Chilling & Liquidation

Unit 5LNG

(1 physical phase)Flow: 1124 Ton / hTemperature: -145.8 CºPressure: 43.3 bar Physical phase: Liquid

1- C1 89.04 %2- C2 5.24%9-He 0.05% 10-N2 5.65%

Natural Gas(1 physical phase)Flow: 1124 Ton / hTemperature: 36.5 CºPressure: 66.5 bar Physical phase: Vapor

1- C1 89.04 %2- C2 5.24%9-He 0.05% 10-N2 5.65%

Process AreaUnit 5 – Gas Chilling & Liquidation

A) Liquefying the main stream of vapor into liquid.

Basic Principle

The method used to cool down and liquefy the main stream of vapor is by

forcing the vapor to go through six evaporators.

The six evaporators belongs to three refrigeration cycles, the first

refrigeration cycle used C3 as main refrigerant item, the second

refrigeration cycle used mixed refrigerant from C1 & C2 as main refrigerant

item, and the third refrigeration cycle used N2 as main refrigerant item.

Process AreaUnit 5 – Gas Chilling & Liquidation

Natural Gas

Feed Gas / HP C3 Evaporator 24-E0501

Feed Gas / MP C3 Evaporator 24-E0502

Feed Gas / LP C3 Evaporator 24-E0503

Feed Gas / LLP C3 Evaporator 24-E0504

Liquefied Natural Gas

Main Cryogenic Heat Exchanger (MR) 24-E0506

Sub-Cooling Heat Exchanger (N2) 24-E0507

Process Area / NorthT4 / Cold Section

Feed Gas C3 Evaporators 24-E0501/2/3/4

Main Cryogenic Heat Exchanger (MR)24-E0506

Sub-Cooling Heat Exchanger (N2)24-E0507

PROCESS AREA

North East Corner

Main Cryogenic Heat Exchanger (MR)24-E0506

Sub-Cooling Heat Exchanger (N2)24-E0507

Process AreaUnit 8 N2 Rejection & He Recovery

A) Taking out the maximum quantity of Nitrogen (N2) and Helium (He) from the main stream of liquid.

Unit 8 N2 Rejection & He Recovery

Unit 8LNG

(1 physical phase)Flow: 1124 Ton / hTemperature: -145.8 CºPressure: 43.3 bar Physical phase: Liquid

1- C1 89.04 %2- C2 5.24%9-He 0.05%10-N2 5.65%

LNG(1 physical phase)Flow: 963 Ton / hTemperature: -159.6 CºPressure: 8.8 barPhysical phase: Liquid

1- C1 93.30 %2- C2 5.95%9-He 0.00% 10-N2 0.75%N2

&He

LNG ( Tank)(1 physical phase)Temperature: -162 CºPressure: 1.1 barPhysical phase: Liquid

Process AreaUnit 8 N2 Rejection & He Recovery

• Taking out the maximum quantity of Nitrogen (N2) and Helium (He) from the main stream of liquid.

Basic Principle

The method used to take out Nitrogen and Helium from the main stream of Liquid is by reducing the pressure, so almost all the quantity N2 & He will evaporate

By reducing the pressure from 43.4 bar to 3.2 bar & with Temperature equal to -160 Cº , almost all N2 & He will evaporate, and they will be easily separated from main stream of vapor by gravity.

Process AreaUnit 8 N2 Rejection & He Recovery

LNG Hydraulic Turbine 24-HT0801A/B

LNG Flash Drum 24-V0801

Nitrogen Rejection Re Boiler 24-E081

Nitrogen Rejection Column 24-C0801

Liquefied Natural Gas / Final Product

Liquefied Natural Gas

LNG Product Pump 24-P0801A/B/C

LNG Tanks / OFF Plot

LNG Hydraulic Turbine24-HT0801A/B

Nitrogen Rejection Column 24-C0801

PROCESS AREA

North East Corner

Nitrogen Rejection Column24-C0801