7.1 DESIGN BASIS FOR PROPANE REFRIGERANT FACILITY 7.1.1 Feedstock Characteristics and Capacity
The composition and properties of the propane refrigerant used in this facility, are as below:
Ethane: maximum 0.5 mol%
Propane: minimum 99.0 mol%
C4 and heavier: maximum 0.5 mol%
The Propane Refrigeration Unit consists of a closed loop in which the propane is flashed, vaporized, recompressed and condensed.
Compressor shall be capable of restart-up from settle-out condition
The settle out condition is determined from bubble pressure at maximum ambient temperature 140°F (60 °C). When the temperature of system is over 140°F (60 °C), the propane will be vented to the Low Pressure Fuel Gas system.
7.1.2 Equipment Design Requirements
All equipment and lines in the Propane Refrigeration Unit will be designed to accommodate the required flow rates to supply the cooling duties of the LPG Train-4 Plant.
As the Feed Gas compositions provided by KNPC are very wide for the design cases, the Rich Feed case will not have any design margins applied to the sizing of the equipment. For the other cases, the design margins will be included in the Equipment Data Sheets as 20 percent. In case of compressor suction vessel, the design margins will be applied in Equipment Data Sheets as 25 percent.
7.1.3 Equipment Design Consideration Compressor
C-235-001A/B Propane Refrigerant Compressor
Two (2) Propane Refrigerant Compressors have been provided (2 x 50%). Each compressor is driven by a dedicated gas turbine. Gas turbine is heavy- duty industrial type and capable of dual firing (fuel gas & gas oil). Fuel gas is
normally used for turbine operation and when fuel gas is not available, then gas oil will be used to run the turbines. The exhaust gas from each gas turbine will be directed to the respective Heat Recovery Steam Generator (one HRSG per gas turbine train) to recover heat and produce high pressure steam.
Heat Exchangers
E-235-001 Propane Refrigerant Condenser
Propane Refrigerant Condensers (E-235-001) are designed to cool compressor discharge down to condensing temperature and uses sea water as a cooling media.
E-235-002 Propane Refrigerant Subcooler
Propane Refrigerant Subcooler (E-235-002) is designed to cool down liquid propane refrigerant coming out from V-235-001 and uses cold heat of ethane product.
Drums
V-235-001 Propane Refrigerant Accumulator
This horizontal drum purpose is to provide a liquid propane refrigerant buffer (Surge) to overcome any process or propane refrigerant system upsets. V-235-002 Propane Refrigerant Compressor LP Suction Drum
This vertical drum separates Propane vapor and liquid from the vapor to the suction of the Propane Refrigerant Compressor. It is equipped with a mesh pad in the vapor outlet to avoid any liquid carry-over to the Low pressure suction of the Propane Refrigerant Compressor. This drum also serves as the inventory of LP Propane Refrigerant used to cool the Propane Product in E- 235-003, the Propane Product LP Refrigerant Cooler. It is also provided with a special diffuser pipe to cool down the hot anti-surge stream, by vaporizing the liquid Propane Refrigerant contained in the bottom section.
V-235-003 Propane Refrigerant Compressor MP Suction Drum
This vertical drum separates Medium Pressure Propane vapor and liquids. It is equipped with a mesh pad to avoid any liquid carry-over to the second- stage, Propane Refrigerant Compressor suction. It is equipped with a special diffuser pipe to cool down the hot anti-surge stream, by vaporizing the liquid
Propane Refrigerant contained in the bottom section.
V-235-004 Propane Refrigerant Compressor HP Suction Drum
This vertical drum separates High Pressure Propane vapor and liquids. It is equipped with a mesh pad to avoid any liquid carry-over to the third-stage Propane Refrigerant Compressor suction. It is equipped with a special diffuser pipe to cool down the hot anti-surge stream, by vaporizing liquid Propane Refrigerant contained in the bottom section.
7.1.4 Propane Accumulator Pressure
The pressure in Propane Refrigerant Accumulator, V-235-001 is maintained by means of hot gas by-pass around the Propane Refrigerant Condenser, E-235-001. A differential pressure controller (PDC) maintains a constant pressure drop through the Propane Refrigerant Condenser, E-235-001, to keep the hot gas by pass valve under control whatever the flow through the E-235-001.
7.2 DESIGN BASIS FOR DEEP REFRIGERANT FACILITY 7.2.1 Feedstock Characteristics and Capacity
The composition of the deep refrigerant which has been considered:
Ethane: 30 mol% or Ethane: 37 mol%
Propylene: 70 mol% Propane: 63 mol%
The Deep Refrigeration Unit consists in a closed loop in which the deep refrigerant (ethane and propylene mixture) is flashed, vaporized, recompressed and condensed.
Compressor shall be capable of restart-up from settle-out condition
The settle out condition is determined from bubble pressure at maximum ambient temperature 140°F (60 °C). When the temperature of system become over 140°F (60 °C), the will be vented to flare system. De-ethaniser ovhd will be used as make up for ethane.
7.2.2 Equipment Design Requirements
All equipment and lines in the Deep Refrigeration Unit will be designed to accommodate the flow rate required to supply the cooling duty of the Propane Product Deep Refrigerant Chiller, E-234-003.
cases, the Rich Feed case will not have any design margins applied to the sizing of the equipment. For the other cases, the design margins will be included in the Equipment Data Sheets as 20 percent. In case of compressor suction vessel, the design margins will be applied in Equipment Data Sheets as 25 percent.
7.2.3 Equipment Design Consideration Compressor
C-235-011 Deep Refrigerant Compressor
The Deep Refrigerant Compressor(C-235-011) is a centrifugal type, driven by steam turbine with load controller and is provided with anti-surge devices.
Heat Exchangers
E-235-011 Deep Refrigerant Condenser
Deep Refrigerant Condenser (E-235-011) is designed to cool compressor discharge down to condensing temperature and uses sea water as a cooling media.
E-235-012 Deep Refrigerant Subcooler
Deep Refrigerant Subcooler(E-235-012) is designed to cool down liquid deep refrigerant coming out from V-235-011 to sub-cooled condition and uses cold heat of propane refrigerant.
Drums
V-235-011 Deep Refrigerant Accumulator
This horizontal drum purpose is to provide a liquid deep refrigerant buffer to overcome any process or deep refrigerant system upsets.
V-235-012 Deep Refrigerant Compressor Suction Drum
This vertical drum is to separate gas and potential liquid. It is equipped with a mesh to avoid any liquid carry-over to Deep Refrigerant Compressor suction.
7.2.4 Deep Refrigerant Accumulator Pressure
Pressure in Deep Refrigerant Accumulator, V-235-011 is maintained by means of pressure control valve to .