Transcript Mitsubishi Heavy Industries, Ltd. Industrial Prospective for Hydrogen Utilization - Safety Aspect -

Industrial Prospective
for Hydrogen Utilization
- Safety Aspect -
10 September 2005
K.Takeno
Mitsubishi Heavy Industries, Ltd.
MHI’s Activities for Hydrogen
MHI, general machinery and power plant maker,
focuses on two aspects concerning hydrogen.
1. When hydrogen is used as the alternative
energy resources from fossil energy, we should
provide the high-quality and high-efficiency
devices for hydrogen production, storage, and
utilization.
2. Utilization as the media of energy chain among
natural reproducible energy (wind, solar,
geothermal, water, biomass, etc.), and nuclear
energy.
Energy Chain through Hydrogen
Natural Gas
Gas Engine
(η～44%)
Fossil Energy
Steam
Reformation
H2
(Natural Gas, Oil)
Membrane
Reformation
Gas Turbine
Storage of
Hydrogen
(η～41%)
On-site hydrogen station
PEFC
Natural Energy
(Wind, Solar, Biomass)
Electricity
(η～60%)
Electrolysis
of Water
H2
Nuclear Energy
Direct Production
from Water
Special Use
(rocket etc)
As the final conversion device from hydrogen, PEFC has highest efficiency
Role of Hydrogen in Natural Energy System
Electricity
DC/AC
DC/AC
H2
Wind Power
O2
Solid Polymer Water
Electrolysis
Solar Cell
Rechargeable battery
Methanol
(Storage)
Polymer Electrolyte
Fuel Cell
Solid Oxide Fuel Cell
Engine
Biomass Gasification
to produce H2 and CO
Power Source
If biomass gasification is combined, performance becomes higher (oxygen from
electrolysis can be utilized and carbon from biomass can be fixed to liquid fuel).
Introduction of Future Plan (RERE System)
＊RERE(Renewable Energy based Rural Electrification)
Research on Safety
Wind
Buoyancy
Mixing of air
with H2
Flow & Diffusion
LH2 : Evaporation Diffusion
GH2 : Diffusion
Flammable H2/Air Mixture
H2
Tank
EXPLOSION or
Diffusion Flame
Leak of LH2 (Liquid) or
GH2 (High-PressurizedGas)
Pressure Wave
Radiation
Research on Safety (continued)
Hypothesis Accidents
Probability study
# Evaporation of LH2
# Diffusion of GH2
Experiments
# Immediate Ignition ⇒
Computer
Simulation
# Delayed Ignition
⇒
Diffusion Flame
Explosion
# Spread of Flammable Mixture
# Scale of Diffusion Flame
Evaluation of Safety
(Risk Analysis)
# Propagation of Pressure Wave
# Radiation from High Temp. Steam
Safety Regulation
Research on Safety (continued)
3.6m
21m
High-pressure H2 flame（d=10mm，P=28MPa）
(Visualized by Na addition)
Length of 火炎長　Flame Lf　(m m )
100000
10000
16700･M0.5
1000
100
0.0001
Nozzle
diam.
噴出口径
(m m )
10.0
2.0
0.53
0.001
0.01
0.1
M (kg/s)
Flow Rate of流量　H2 Gas
1
5.0
1.17
0.32
10
L f / d  399.2  P 0.5
rf max / d  71.6  P 0.48
Lig=31.5mm
Schuliren photo image（d=1mm，P=20MPa）
(Flame is stabilized behind shock wave)
P : [ MPa ]
Correlation of flame scale
Lf: flame length
rfmax: maximum flame diameter
d: nozzle (opening) diameter
This formula is used for the Japanese
regulation of hydrogen safety.
Research on Safety (continued)
Large scale (300m3) explosion experiment,
conducted by IAE / SRI
(H2 (30%) / Air mixture)
Typical result on the atmospheric diffusion of leaked
H2 at an assumed hydrogen supply station.
(40MPa-400m3, d=10mm opening, t=3s)
75～90m/s
[Pa]
Velocity of flame propagation
Pressure distribution at t=100ms
Principal Conclusion and Perspectives
Total Efficiency
from NG
via H2 direct use
Natural Gas
Gas Engine
(η～43%)
Fossil Energy
Steam
Reformation
H2
(Natural Gas, Oil)
Membrane
Reformation
Gas Turbine
Storage of
Hydrogen
(η～39%)
PEFC
Natural Energy
(Wind, Solar, Biomass)
Electricity
(η～60%)
Electrolysis
of Water
H2
Nuclear Energy
Direct Production
from Water
～29% ～42%
～27% ～39%
～42%
Special Use
(rocket etc)
# Problem seems to be the energy efficiency. It is difficult to overcome the direct use of natural gas to gas
engine or turbine.
# At the standpoint of industrial researcher, it is the urgent demand to raise the conversion efficiency from
NG or nuclear energy to hydrogen. Specially, MHI expects membrane reformer, which can be operated
at low temperature (～550℃) and conversion efficiency is high (～75%).
# From CO2 problem, the use of natural renewable energy is expanding globally. If hydrogen is the core of
energy flow, many kinds of natural energy can be combined.
Membrane Reformer
CH4
Atomic Furnace
Ｈ２
CH4＋H2O+heat→CO+3H2
Reformation
Catarist
Membrane
Catarist
City gas
Steam
Hydrogen
Heat
Membrane
This can be operated at low temperature (～550℃) and conversion efficiency is high (～75%)