technical aspects of lng-compression thermodynamic design
TRANSCRIPT
Technical Aspects of LNG-CompressionThermodynamic design
Β© NEA GROUP2
Thermodynamic design basics for
reciprocating compressors
Specialities of low suction temperature
Technical Aspects of LNG-CompressionThermodynamic design
3
Power and flow determination
Work per cycle
Volumetric flow per cycle
π = ππ β ππ ππππ
π1π = ππ β πβ
αΆπ1π = π1π β ππ ππππ
Β© NEA GROUP
βπ β ππ
βΰΆ»π β ππ
Technical Aspects of LNG-CompressionThermodynamic design
4
Flow determination
Degree of back expansion:
β’ Relative clearance:
β’ Polytropic change:
Β»
ππ =πβ²
πβ=πβ β ππ πβ
= 1 βππ πβ
= 1 βππ π0
βπ0πβ
π0 + ππ π0
= 1 +ππ π0
=π2β²
π1
1ππππ
Β© NEA GROUP
ππ = 1 β π βπ2β²
π1
1ππππ
β 1
π =π0πβ
ππ π0
=π2β²
π1
1ππππ
β 1
Technical Aspects of LNG-CompressionThermodynamic design
5
Flow determination
Degree of back expansion:
Β© NEA GROUP
ππ = 1 β π βπ2β²
π1
1ππππ
β 1
lR
VS = V0
Technical Aspects of LNG-CompressionThermodynamic design
6
Flow determination
Degree of heating up
Β© NEA GROUP
ππ=20Β°πΆ = ππ2β²
π1, π
π = π ππ=20Β°πΆ , ππ
Technical Aspects of LNG-CompressionThermodynamic design
7
Flow determination
Degree of leakage
β’ An in-house leakage flow calculation tool based on conservation of energy and mass was developed to calculate the transient leakage flow of pistons/packings
Β© NEA GROUP
πΏ = π π2β² , π2
β²,π2β²
π1, π , π , π, π΄
Technical Aspects of LNG-CompressionExample of a horizontal LNG BOG compressor
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β’ Two stages
β’ Suction valve unloading control +
β’ Clearance pocket control
Β© NEA GROUP
Technical Aspects of LNG-Compression
Β© NEA GROUP9
Example of a horizontal BOG LNG compressor
Technical Aspects of LNG-CompressionSummary
Β© NEA GROUP10
β’ Thermodynamic design basics for power and flow determination of
reciprocating compressors were discussed
β’ Influence of low suction temperature for the flow calculation were
presented
β’ A complete design process of an LNF BOG compressor by means of NEAβs
design program KOΒ³ were described
