Liquefied Propane Gas,
the Preferred Working Fluid for
Cryogenic Power Cycles
Joel V. Madison
CEO
Ebara International Corporation
Cryodynamics Division
Sparks, Nevada, USA
[email protected]
5th Global Technology Conference (GTC-2012)
25th World LP Gas Forum
11-13 September 2012
Bali, Indonesia
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.
Company Profile
EBARA Headquarters and Factory, Nevada, USA
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
Ebara LNG Test Facility in Nevada
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.
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.
Traditional Power Recovery Cycle
High Pressure
LNG
Vaporizer
Natural Gas
Pipeline
Heater
Pump
Expander
Traditional Power Recovery Cycle
Traditional Power Recovery Cycle
Combined Machine
Turbine-Generator / Pump-Motor
Net Generated Power = hNP
hNP = (h3 – h4) – (h2 – h1)
Turbine Power
Pump Power
Current Power Recovery Cycle
with Two-Phase Expansion
Pressure (Mpa)
Two-Phase Power Cycle with Propane as Working Fluid
3
2
1
4
Enthalpy (kJ/kg)
Schematic
of the
Two-Phase
Power
Cycle
Schematic Layout of the Two-Phase Power Cycle
Vaporizer
High Pressure
LNG
Natural Gas
Pipeline
12 Pump
23 Heat input
4
34 Expansion
Expander
41 Condensation
Cooling
3
1
Pump
2
Heater
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
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
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.
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
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
Nozzle Ring with converging nozzles
generates high-velocity vortex flow
Reaction turbine runner converts
angular fluid momentum into shaft torque
A radial outflow turbine for power generation by
isentropic two-phase expansion to lower pressure
Two-Phase Expander with
Two-Phase Draft Tube
for Pressure Recovery
and Condensation
Thermodynamic Expansion with Two-Phase Draft Tube
P1
Saturation Curve
Pressure
P2
P3
Joule – Thomson Valve
Expander
Two Phase Expander w/Jet Exducer
Two Phase Expander w/Two-Phase Draft Tube
Enthalpy
Liquefied Propane Expanders
for Single Phase and for
Two-Phase Expansion are
Proven Equipment in
Existing LNG Liquefaction
Trains
Liquefied Propane Expander
for Single Phase Expansion
for Two-Phase Expansion
Two-Phase
Liquefied Gas
Expander
at Ebara
Manufacturing
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 2009.
28
Field Experience
Thank You