Liquefied Propane Gas, the Preferred Working Fluid for Cryogenic Power Cycles

Transcription

1 Liquefied Propane Gas, the Preferred Working Fluid for Cryogenic Power Cycles Joel V. Madison CEO Ebara International Corporation Cryodynamics Division Sparks, Nevada, USA 5 th Global Technology Conference (GTC-2012) 25 th World LP Gas Forum September 2012 Bali, Indonesia

2 Joel attended University at the United States Air Force Academy, University of Nevada and Pennsylvania State University, earning a B.S. Degree in Mechanical Engineering and a M.S. Degree in Aerospace Engineering. Prior to joining Ebara, Joel as a research engineer for the Advanced Programs Department of the Rocketdyne Division of Rockwell International. During this time he was involved in analysis, development and testing of prototype hypersonic scramjet engines in support of NASA and U.S. Air Force Programs. Since joining Ebara International in 1995 he has worked as a Project Engineer, Project Manager, Chief Engineer, President of the Cryodynamics Division and eventually CEO of Ebara International Corporation.

3 Company Profile EBARA Headquarters and Factory, Nevada, USA

4 EBARA International Corporation Cryodynamics Division Company Profile Established in 1973 Manufacturer of custom engineered liquefied gas pumps and expanders Located in Sparks, Nevada, USA Division of Ebara Corporation of Japan 5000 M2 factory with a modern, dedicated liquefied gas test facility ISO 9001 Certified

5 Ebara LNG Test Facility in Nevada

6 LNG Regasification Process Liquid Natural Gas is unloaded from LNG vessels at the receiving terminal and stored in insulated tanks at atmospheric pressure and a temperature of 111 Kelvin. For regasification and distribution the LNG is pumped to high pressure and then heated to vaporize into its gaseous state. The heat to regasify the LNG is provided by sea water using the heat naturally stored in the sea or by other heat sources.

7 Power Recovery LNG regasification plants are large heat sinks and require also large heat sources. The differences in temperatures between the heat sources and the heat sinks are in the range of 170 Celsius providing the preconditions for an efficient power recovery. The Rankine Cycle is a thermodynamic cycle which converts heat into work. The heat is supplied externally to a closed loop with a particular working fluid, and requires also a heat sink. This cycle generates about 80% of all global electric power.

8 Traditional Power Recovery Cycle High Pressure LNG Vaporizer Natural Gas Pipeline Pump Heater Expander

9 Traditional Power Recovery Cycle Traditional Power Recovery Cycle

10 Combined Machine Turbine-Generator / Pump-Motor Net Generated Power = h NP h NP = (h 3 h 4 ) (h 2 h 1 ) Turbine Power Pump Power

11 Current Power Recovery Cycle with Two-Phase Expansion

12 Two-Phase Power Cycle with Propane as Working Fluid Pressure (Mpa) Enthalpy (kj/kg)

13 Schematic of the Two-Phase Power Cycle

14 Schematic Layout of the Two-Phase Power Cycle High Pressure LNG Vaporizer Natural Gas Pipeline 4 Expander Pump 2 3 Heat input 3 4 Expansion 4 1 Condensation Cooling 1 Pump 2 Heater

15 Compact Assembly of a pump and a two-phase expander The proposed working fluid is LPG The LPG is passed through two separate heat exchangers and a single machine which combines a pump and a two-phase expander

16 Advantages of the Compact Assembly The expander work output is larger than the pump work input and the difference in work is converted by the generator into electrical energy The losses of a separate pump motor are eliminated The losses of the induction generator are recovered and used as heat source to heat the working fluid in addition to the heat from sea water and other heat sources Any leakage of the working fluid is within a closed loop and occurs only between pump and expander

17 Advantages continued Any leakage of the working fluid is minimized due to equal pressure on both sides of the seal, and small leakages are within a closed loop and occur only between pump, expander and generator. The axial thrust is minimized due to opposing directions of the thrust forces decreasing the bearing friction and increasing the bearing life.

18 Existing Field Proven Two-Phase Expanders Cross section of a Two-Phase Liquefied Gas Expander inside pressurized containment vessel with lower inlet and upper outlet nozzle Corresponds in the power cycle to position 3 4 : Isentropic two-phase expansion to a lower pressure

19 Two-Phase hydraulic assembly with nozzle ring (red), turbine runner (yellow), jet exducer (green) and two-phase draft tube (metallic) 3 4 Isentropic two-phase expansion to a lower pressure

20 Nozzle Ring with converging nozzles generates high-velocity vortex flow

21 Reaction turbine runner converts angular fluid momentum into shaft torque

22 A radial outflow turbine for power generation by isentropic two-phase expansion to lower pressure

23 Two-Phase Expander with Two-Phase Draft Tube for Pressure Recovery and Condensation

24 Thermodynamic Expansion with Two-Phase Draft Tube P 1 Saturation Curve P 2 Pressure P 3 Joule Thomson Valve Expander Two Phase Expander w/jet Exducer Two Phase Expander w/two-phase Draft Tube Enthalpy

25 Liquefied Propane Expanders for Single Phase and for Two-Phase Expansion are Proven Equipment in Existing LNG Liquefaction Trains

26 Liquefied Propane Expander for Single Phase Expansion for Two-Phase Expansion

27 Two-Phase Liquefied Gas Expander at Ebara Manufacturing

28 Field Experience with Liquefied Gas Two-Phase Expanders Two-phase rich liquid feed expanders installed in 2003 are operating successfully at PGNiG, Odalanów, Poland. Additional two-phase expanders are installed in the feed to the lower column during Field Experience

29 Thank You