1.
Design Condition
1.1 Driving Steam
Geothermal steam is branched off the main steam line and used as driving steam of ejector.
(1) Pressure : 7.6 bar.a
(2) Temperature : 168.3 deg.C (Saturated)
(3) NCG content : 2.0 wt %
(4) Composition of NCG CO2 : 96.24 wt %
H2S : 2.25 wt %
H2 : 0.01 wt %
N2 : 0.58 wt %
O2 : 0.65 wt %
CH4 : 0.01 wt %
Ar : 0.26 wt %
Average molecular weight : 43.37
1.2 Cooling Water
Cold water is supplied from cooling tower bassin by primary cooling water pump
as the cooling water for inter-condenser and seal water for vacuum pump.
(1) Pressure : Min. 1.0 bar.g
(2) Temperature : 30.0 deg. C at Design point
30.0 deg. C at 105% overload condition
1.3 Gas suction flow
100% capacity of gas suction flow rate is based on turbine 100% load condition.
Refer to heat balance diagram.
Item Unit Design Point 105% overload
NCG kg/h 7296 7899
Flow rate Air kg/h 300 295
Steam kg/h 4477 4034
Temperature deg.C 34.0 34.3
Turbine gland leaking steam/air flow rate, which is decided by turbine construction,
is added as inter-condenser load.
(1) Flow rate
Air : 70 kg/h
Steam : 124 kg/h
(2) Temperature : 145.0 deg.C
1.4 Gas suction pressure
Gas suction pressure at ejector gas suction nozzle is calculated as follows.
Item Unit Design Point 105% overload
Condenser internal pressure bar.a 0.100 0.108
Condenser G.C.Z loss (-) bar 0.005 0.005
Pressure drop of suction piping (-) bar 0.005 0.005
Pressure at ejector suction bar.a 0.090 0.098
1.5 Gas discharge
Gas discharge pressure at seal water separator gas outlet nozzle is determined as follows.
Atmospheric pressure bar 0.950
Pressure drop of discharge piping (+) bar 0.040
Puressure at seal water separator gas outlet bar.a 0.990
2. Specification and Study report
2.1 Composition
Hybrid system consist of first stage steam ejector and second stage vacuum pump
2.2 Ejector system
2.2.1 Steam jet ejector
(1) Type : Multi nozzle steam jet ejector
(2) Quantity : 2 sets (1 set is stand-by)
(3) Rated Specification
Capacity of one ejector is determined based on design point.
Item Unit Design Point 105% overload
Extraction amount by DAE (*1) kg/h 12034 11987
Inlet pressure bar.a 0.090 0.098
Outlet pressure bar.a 0.263 0.279
*1) DAE (Dry Air Equivalent flow rate) is calculated from section 1.
(4) Material
Body : 316L stainless steel
Steam chest : 316L stainless steel
Motive steam nozzle : 316L stainless steel
(5) Driving steam consumption (for one ejector operation)
Less than 14430 kg/h
according to the manufacture’s design standard
2.2.2 Inter-condenser
(1) Type : Direct contact spray type condenser
(2) Capacity : 1 set (Common use)
Inter-condenser can handle gas/steam flow rate
at 2 x 100% ejectors parallel operating condition.
(3) Material
Body : 316L stainless steel
Water header : 316L stainless steel
(4) Cooling water flow rate and required pressure
a) One ejector operating condition
800 m3/h / 0.218 bar.a according to the manufacture’s design standard
b) Two ejector operating condition
1200 m3/h / 0.810 bar.g according to the manufacture’s design standard
(5) Fluid condition at inter-condenser outlet
Item Unit Design Point 105% overload
Pressure bar.a 0.257 0.273
Temperature Deg.C 40.0 40.3
NCG kg/h 7585 8188
Flow rate Air kg/h 383 378
Steam kg/h 1347 1361
Drain flow rate : 813 m3/h at one ejector operation
1207 m3/h at two ejector operation
2.3 Vacum pump unit
(1) Type : Liquid ring vacuum pump (LRVP) with motor, gear reducer, separator and a
auxiliaries.
(2) Quantity : 2 sets (1 set is stand-by)
(3) Rated Specification :
Item Unit Design Point 105 % overload
Extraction amount by volume (*2) m3 / min 407 406
Inlet pressure bar.a 0.254 0.270
Discharge pressure bar.a 0.990 0.990
*2) Volume flow rate is calculate from section 2.2.2
(3) Specification
Rated capacity of one vacuum pump is covered 100% design condition.
Rated capacity : 407 m3/min
Rotating speed : 318 rpm
Shaft power : 572 kW
Seal water flow rate : 50 m3/h (Drain : 52 m3/h)
(4) Material
Rotor : 316 stainless steel
Cone : 316 stainless steel
Housing : 316 stainless steel
Head : 316 stainless steel
Shaft : 316 stainless steel
Discharge separator : 316L stainless steel
(5) Motor
Type : Squirrel cage steel
Power source : 6300 V. 3 phase. 50Hz
Rated output : 665 kW
Rotating speed : 1500 rpm (SS)
(6) Gear reducer
Type : Helical gear. Water cooled (requreid flow rate : 0.7m3/h)
