JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016 - 45

Specialised dangerous goods tanks for the transport of highly corrosive chemicals

reduced fuel costs, reduced emissions, improved transported product quality, and
better asset utilisation.

A high-quality tank liner
The Omni Tanker A and AB tanks are
the realisation of the vision of company
founder Bill Rodgers, who saw the need
for lightweight, highly corrosion resistant
tankers for the chemicals industry some
10 years ago. The development started in
2006. The first stage gate was the liner. Mr
Rodgers, who had worked in the area of Fibre Reinforced Polymer (FRP) tanks and
structures for approximately forty years,
recognised the need to develop a highquality tank liner, which would not suffer
the same adverse effects as standard FRP
tanks with FRP liners or rubber liners in
chemicals such as sodium hypochlorite.
Standard liners, while effective for many
corrosive chemicals, break down in service
due to environmental stress cracking and
gradual embrittlement, with seams and
joins being particularly susceptible to the
breakdown.

The third stage gate in the development
project was passed in late 2007, when the
first full-size prototype tank was built and
achieved Dangerous Goods approval for
the transport of Class 8 corrosive liquids in
Australia, in the form of the Omni Tanker
A Tank. This represented completion of
the initial formal development project, and
led to the commencement of continuous
production. A follow-up project to adapt
the A tank technology to a short wheel
base version, the AB tank, was launched
immediately and this tank was brought

into service in 2011.
With the product type approval granted,
the Omni Tanker A and AB tanks gained
interest and subsequent orders from several prominent Australian clients including Chemtrans, Coogee Chemicals, Toll
and McColls. The Omni Tanker A and AB
tanks have been in service since the introduction dates listed above and are the preferred choice for Class 8 corrosive chemical transport in Australia. The tanks have
been noted to perform very well by Omni
Tanker and customers alike, verifying that
the original design objectives have been
achieved.

Chemical transport
Two key innovations come together to
form the Omni Tanker, which are the
thermoplastic liner with high adhesion strength to the composite as well as
chemical resistance, and the low-weight
composite tank solution integrating the
thermoplastic liner. The Omni Tanker
liner, developed specifically for composite
applications, is a platform technology that
has been initially deployed to the corrosive
chemical transport industry in Australia.
The liner is being considered for a number
of applications outside of the current technology deployment. These include tanks
for the transport of milk or other foodstuffs, rail wagon tanks, IBCs, marine fuel
tanks, aircraft fuel tanks and storage tanks.
The A and AB tanks, in their current form,
are suitable for the transport of milk and
other foodstuffs, and non-corrosive chemicals, and an effort is underway to expand
the product use into these applications.
The next confirmed application for the
Omni Tanker liner platform technology
will be an adaptation of the A and AB tanks
into a family of large SWAP tanks, ISO
tanks and mini-tanks for the European and
Australian markets. These tanks are currently undergoing UN ADR (dangerous
goods transport by road), UN RID (dangerous goods transport by rail), and CSC
(international convention for safe containers) type approval. Products are expected
to enter the market in 2016.

No107 August - September 2016

More information:
www.omnitanker.com

/ jec composites magazine

Feature Wind energy

Mr Rodgers noted the benefits of thermoplastic materials in terms of chemical resistance, while acknowledging the
drawback of poor adhesion between such
materials and FRPs. As such, a method of
obtaining good adhesion between a thermoplastic liner and a thermoset matrix
FRP was sought. The concept of combining a seamless thermoplastic liner vessel
with an FRP surrounding structure was
tested on a small scale in 2006. Of particular interest was the combination of polyolefins such as polyethylene and fluoropolymers such as Halar as liners, to thermoset
vinyl esters and epoxies to be used as composite matrices. Several different pathways
were explored to reliably achieve a strong
and repeatable bond between these two
incompatible materials. A liner solution
was eventually found, and the patenting
process started immediately.
Omni Tanker have since secured a number of international patents on the liner
manufacture and its combination with
FRPs. The ability to manufacture a seamless hollow vessel was a major step forward
in technological advancement, as previ-

ously all thermoplastic vessels contained
seams that were generally the points where
breakdown commenced in service. The
strength of the interface between the thermoplastic and thermoset materials was determined to exceed 8 MPa in shear which
was deemed acceptable for the target application as it would result in high long
term durability under the expected service
loads. Achieving this seamless liner with
high adhesion strength to an FRP material
represented the achievement of the major
project milestone associated with the first
stage gate.
The second stage gate in the project was the
development of a composite tank structure
to house the liner and liquid contained
within it. The structure had to exhibit suitable chemical resistance for service and be
lightweight, whilst permitting insulation
of liquid cargoes to prevent breakdown
during transport. As such, the materials
selected for the structural portions of the
tank were vinyl ester resin for chemical resistance, and carbon fibre reinforcement to
minimise the tank weight. Finite element
analysis using Strand 7 was employed to
generate an optimised layup sequence for
the carbon reinforcement, with the tank
being optimised for both strength and fatigue resistance.
The benefit of using anisotropic CFRPs is
that the material properties could be tailored to the stress field based on directional load requirements. Completion of the
tank design according to key mass, chemical resistance and insulation requirements
represented the achievement of the major
project milestone associated with the second stage gate.

http://www.omnitanker.com

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #107 - August/September 2016