Internship: Day 1

Sejujurnya gue ga gitu ngerti dengan apa yang diajarin disini. Ups,sorry, gue ga diajarin, gue terpaksa belajar sendiri karena emang ga ada yang bisa (dan gue kenal) untuk ditanyain kecuali si Ibu Yus yang hmgga kini hilang entah kemana. Okelah, daripada bengong mending gue nulis aja apa yang udah bisa gue pahami dan mana yang kira-kira harus gue tanyain ke si Ibu Yus (kalau dia sudah menunjukkan batang hidungnya lagi)

Air Separation Process
Produsen: air Liquide Engineering Japan, Co. / Air Liquide Indonesia

General Description of Process
1. Compression of Atmospheric Air
The atmospheric air is compressed by an air compressor (C01) to the minimum service pressure required for operation of the plant. It is then cooled in an after-cooler to room temp. The air is subsequently delivered to a refrigeration unit and molecular sieves unit.
2. Pre purification of feed air
The compressed air is further cooled to near 10ºC by refrigerator (X01). Condensing moisture contained in the air is separated from the air in water separator (V07), because of decreasing the adsorption capacity of the molecular sieves.
Then, the air is fed to molecular sieves unit, which consists of Air Purification Vessel (R01/R02). Carbon dioxide (CO2) and residual moisture in the air is absorbed in one of the towers, while another tower is reactivated with waste gas delivered from the cold box. The changeover of two towers is automatically done every 3 hours.
A part of dry air is fed to the Electrical Reactivation Heater (E08) as seal gas and to each instrument as instrument gas.
3. Production of Nitrogen
The compressed air free of CO2, moisture and other impurities is sent to the Low Temperature Separation Unit. The compressed air is cooled to near its liquefaction temperature in the main heat exchanger (E01) by heat exchange with outgoing product gas and waste gas, and introduced into the nitrogen column (K01).
In this column, the air is separated into pure gaseous nitrogen at the top and liquid rich in oxygen (called “rich liquid”) at the bottom.
Most of gaseous nitrogen is liquefied in the Nitrogen Condenser (E02) located at the top of the nitrogen column by heat exchange with evaporating rich liquid. The liquefied nitrogen is sent back to the nitrogen column as reflux. A part of gaseous nitrogen is withdrawn from the upper section of the Nitrogen Column as product after warming up in the main heat exchanger (E01).
Another part of liquid nitrogen from the upper section of the nitrogen column is withdrawn as product and sent to the storage tank.
The rich liquid in bottom of nitrogen column (K01) is sent to the Nitrogen Condenser (E02). The rich liquid is evaporated in the nitrogen condenser (EO2).
A part of rich liquid in the nitrogen condenser (E02) is purged to atmosphere after evaporating in CnHm Purge Vaporizer (E70) to prevent an accumulation of hydrocarbons in the nitrogen condenser (E02).
Evaporating waste gas is used for reactivation of the air purification vessel (R01/R02). Remain gas is purged out to the atmosphere
4. Production of oxygen
The compressed air is introduced into the Oxygen Column (K40) to reboil the rich liquid at Oxygen Vaporizer (E41). This air is liquefied and sent to Nitrogen Condenser (E02).
The rich liquid is sent to the higher part of an oxygen column, where the rich liquid is separate into high purity liquid oxygen as product and waste gas at the top. Liquid oxygen from the lower section of oxygen vaporizer is withdrawn as product and sent to the storage tank.
Waste gas is warmed up in the main heat exchanger (E01) and used for reactivation of the Air purification vessel (R01/R02). Remain gas is purged out to atmosphere.
5. Supply of cold energy
The coldness inside the cold box is maintained with Air Expansion Turbine (ET01). The compressed air from the air purification vessel (R01/R02) is adiabatically expanded in air expansion turbine (ET01) and lowered the temperature. Low pressure air is used for cooling the feed air in the main heat exchanger (E01) and purged out to atmosphere.
The cold energy required for the operation of the unit is supplied by this cryogenic air.

The Air liquide absorber design includes a double bed of alumina and molecular sieves; this double bed allows regeneration of the absorbent material at lower temperatures than single bed molecular sieve absorber, thereby increasing sieve life.
The cold box is a vacuum insulated type thus optimizing maintenance and layout requirements.
The distillation column and most piping inside the cold box are stainless steel. This ensures long plant lifetime and high corrosion resistance. In addition, stainless steel welding is much easier than aluminum welding should intervention inside the cold box become necessary.
Description of Equipment
I.1 Air compression part
1.1.1 Hepa Filter
HEPA (High efficiency Particulate Air) filter against haze risk on basis of Air Liquide safety rule.
1.1.2 Air compressor
Screw compressor to compress the process air, complete with: air filter, intercooler, after cooler, lubricating apparatus, piping, instrument and safety devices.
Specifications
Flow rate : 4700 Nm3/h
Suction press : 0 MPa
Suction temp. : 27 C
Reltive humid : 80%
Discharge pres : 0.89 MPa
1.1.3 Electric Motor for the air compressor
Specifications
Output : 610 kW
Insulation : class F
Electricity : 2400 V, 50 Hz, 3 phases
Tadi gue udah nanya sama si Bu Yus tentang kenapa sih di alat itu harus dikasih dulu kompresor, padahal kan kalo entar di kompresi, bisa jadi suhunya naik, padahal nanti di tahap kedua rencananya suhunya mesti diturunin….menurut beliau itu karena volum gas kalau missal ga dikompresi bakal jadinya gede banget. Kalo missal volumnya gede banget artinya tangki yang dibutuhkan bakal gede banget juga, dan vessel yang mau dipake nanti gede juga dong, ga irit di ongkos dan ga efisien tempat juga nanti pas proses ga bias banyak nitrogen dan oksigen yang didapat.
I.2 Warm Part
1.2.1 Refrigeration Unit
A skid mounted refrigeration unit comprising compressor with a driving motor, air cooler, condenser, reservoir, oil separator, oil cooler, dryer-filter and piping, and complete with temperature control and safety device.
Specifications
Net duty : 59,000 kcal/h
Temp in/out : 40 C / 10 C
Refrigerant : R134a or equal
Motor output : 30kW
Electricity : 440V, 50Hz, 3Phases
1.2.2. Water Separator
Cylindrical vessel, used to eliminate water mist from the process air, and complete with automatic drain trap.
Specifications
Material : Shell : Carbon steel
  Demister: stainless steel
1.2.3 Valve unit for M/S tower
1. Switch valves: to switch the molecular sieves towers
2. Reactivation heater: multiple sheathed electric heaters to warm up waste gas for normal reactivation and the air for complete reactivation of the adsorbent once a year.
Specifications
Capacity : 42 kW
Electricity : 440V, 50Hz, 3Phases
3. Piping
4. Valves
1.2.4 Warm Skid Structure
It is a structure to mount the equipment in this part. This includes noise protection wall.
Kalo ga salah, valve nya itu ada yang dioperasiin manual, ada juga yang otomatis, buat me-non aktifkan salah satu sieve tiap beberapa jam sekali (kalo di spec sih 3 jam sekali).
I.3 Molecular Sieves Tower
Two sets of cylindrical vessels containing molecular sieves and alumina-gel adsorbents to adsorb moisture and carbon dioxide in the process air.Jadi si molecular sieves ini kerjanya gantian, tujuannya biar ada waktu rehat / regenerasi buat absorben yang ada di dalam sieve nya, biar performanya maksimal.
1. vessel
2. 2. inner mesh
3. insulation material
I.4 Vent Silencer
I.5 low Temperature part
1.5.1 Vessels inside cold box
1.5.1.1 Air exchanger
A plate-fin type heat exchanger to cool incoming process air by returning products streams which are nitrogen and waste gas
Material : aluminum
1.5.1.2 Nitrogen Column
This is a cylindrical vessel complete with a set of rectification trays. Air feed is separate into pure nitrogen at the top and rich liquid at the bottom.
Material : Shell: Stainless steel
  Packing trays: aluminum
1.5.1.3 Oxygen Column
a cylindrical vessel complete with a set of rectification trays. Feed rich liquid is separated into pure oxygen at the bottom and waste gas at the top.
Material : Shell: Stainless steel
  Packing trays: aluminum
1.5.1.4 Nitrogen Condenser
A shell and tube heat exchanger located near by nitrogen column. Nitrogen is liquefied by evaporated rich liquid.
Material: stainless steel
1.5.1.5 Oxygen reboiler
a shell and tube type heat exchanger located at the bottom of the oxygen column to exchange with liquid oxygen.
Material: stainless steel
1.5.2 Cold box casing
This is a perlite-vacuum insulated casing. All piping, valves, supports and brackets within the insulation casing are included. Elements to be contained in the casing will be pre-assembled, fully piped and valved, equipped with instrument and safety devices.
1.5.3 Expansion turbine
It includes expansion turbine and insulation materials and turbine box which is an insulated carbon steel casing.
The expansion tubine is a single stage turbine coupled with an oil brake which acts as brake to generate necessary refrigeration of the plant.
The expansion turbine also includes lubricating apparatus and complete piping which are supplied separately for the site assembling.
Specifications
Flow rate: 2250 nm3/h
Suction pressure: 0.83 MPa
Discharge press: 0.03 MPa

Plant Utilities
1. Design Conditions
a. Atmospheric Conditions
Ambient temp: Des: 27 C Max: 37 C min: 20 C
Relative humidity : 80% 100% 60%
Barometric pressure 0.1013 MPa 0.1013 MPa 0.1013 MPa

2. Utilities
a. Electricity
High voltage : 2400 V, 50 Hz, 3 Phases
Low voltage: 440 V, 50 Hz, 3 phases
Instruments: 110 V, 50 Hz, single phase

Cooling water
Supply pressure: design 0.47 MPa Max 0.47 MPa
Return Press: 0.32 MPa 0.32 MPa
Supply temp: 28 C 32 C
Return Temp: 36 C 40 C

Instrument gas (for start up and emergency)
Supply pressure: 0.5-0.7 MPa
Supply temp: approx. 30 C
Dew point: -40 C or below
Instrument gas shall not be used as seal gas unless its quality has been reviewed and approved by ALE Japan.

Utilities Consumption
The following figures indicate estimated utilities consumption under design conditions.
Utility Units Design
Electricity power kW 630
Cooling water m3/h 120

Plant performance
Product nitrogen
G N2 Flow (Nm3/h) 500
LN2 Flow (Nm3/h) 150
Pressure (GN2) (MPa) 0.7 or more at battery limit
Pressure LN2 (MPa) 0.72 at cold box outlet
Impurity O2 (ppm) 5 or less
Product oxygen
L02 flow 65 Nm3/h
Pressure (LO2) 0.1 or more at cold box outlet
Purity 99.5% or more