JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015 - 19

Evaluating the viability of
thermoplastic composite
pressure vessels
To address issues with highpressure hydrogen storage
vessels, a U.K. consortium
has worked on a thermoplastic composite alternative. The team designed an
unreinforced rotomoulded
acetal liner filament-wound
with acetal/carbon fibre
tapes. This paper describes
the study results to date.

hydroelectric, coal, nuclear, solar, wind, electrolysis of water, and CNG - and therefore
greater energy security and price stability.
For all the promise of FCVs, and despite the
fact that many automakers have programmes
in development or on the road in testing,
there are still significant technical hurdles to
clear before the technology becomes commonplace on our streets and highways. One
important issue is the development of onboard storage tanks capable of safely carrying
sufficient fuel to propel a vehicle the 500 km
equivalent driving range of conventional cars.
Current tank technology is too heavy, costly,
bulky, hard to recycle, and lacks sufficient
durability. However, hydrogen is not an easy
substance to store.

- Evaluating the viability of
thermoplastic composite
pressure vessels ........... p19

APPLICATIONS

thermoplastics

- Epoxy adhesive for a HarleyDavidson motorbike ...... p22
- New GRP enclosure for
extreme environments p25

Issues with current
storage vessels

Being the lightest molecule known, hydrogen
has extremely high energy density per unit
Michael Ruby
weight, but quite low energy density per unit
Global coMposites business ManaGeR
volume. This means that to ensure hydrogencelanese coRp.
powered FCVs have a driving range that
approaches conventional cars, it is necessary
s automakers increase efforts to boost to compress and store the fuel as a gas under
fuel efficiency and reduce tailpipe
high pressures (20-70 MPa). (Hydrogen
emissions to comply with tough legalso can be stored as a liquid at cryogenic
islation phasing in between now and 2025,
temperatures (-253 °C), but this is considinterest in alternative propulsion systems is at ered impractical for passenger cars.) Since
an all-time high. One technology developed hydrogen also is the smallest molecule, the
for the manned space programme and
permeation resistance of storage materials is
pursued by carmakers in the late 1990s and
critical. To store hydrogen at such high presearly 2000s that once again is gaining traction sures, robust pressure vessels are required.
is the fuel cell. A major benefit of a fuel-cell
Currently, there are four types of these tanks:
vehicle (FCV) is that it can be propelled
all-steel (Type I); steel or aluminium liners
with zero tailpipe emissions, since the only
partially wrapped with thermoset epoxy/
by-product of combustion is heat and water. carbon fibre composite (Type II); steel or
The two most popular fuels for FCVs are
aluminium liners fully wrapped with epoxy/
hydrogen (H2) and compressed natural gas
carbon composite (Type III); and plastic
(CNG or methane). When H2 is the fuel of
or rubber liners fully wrapped with epoxy/
choice, it brings the additional benefits of
carbon composite (Type IV). Type I tanks
flexibility of the fuel source - since it can be
were the first available. Type II tanks were
produced locally in most parts of the world
developed as a lighter (although more costly)
from diverse inputs like biomass, geothermal, alternative. Type III tanks offer higher perfor-

No95 March 2015 /

jec composites magazine 19

http://www.jeccomposites.com

JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #95 - Special JEC Europe - March 2015