THE ENERGY INDUSTRY TIMES - OCTOBER 2018
Technology 15
A dairy factory in
Italy is set to install
a cogeneration plant
that uses an Organic
Rankine Cycle (ORC)
that will operate at a
higher temperature
than existing
systems.
Junior Isles reports.
Owners of small Industrial facilities
that require predominantly
steam, as opposed to
hot water and/or electricity, are often
faced with a choice of either installing
steam turbines, small or micro
gas turbines or reciprocating engines
– none of which are an ideal solution
for processes with large steam requirements
but little electricity.
A recent technology advance,
however, now offers what appears
to be the ideal solution for this market
niche. Italian company, Turboden,
has just announced that it is
to deliver what it says will be the
first high ‘Steam & Power Organic
Rankine Cycle (ORC)’ plant to Centrale
del Latte di Brescia for milk
pasteurisation.
The new high temperature cogeneration
solution is claimed to have an
overall efficiency of more than 90
per cent with a high steam output –
typically producing about 75 per cent
steam, 15 per cent electricity and no
hot water.
Commenting on the new technology,
Paolo Bertuzzi, Turboden’s
Managing Director and CEO, said:
“In terms of the market, we realised
that we could address a niche – in
terms of a different combination of
steam, power and size – that is not
covered by other existing cogeneration
technologies.”
Turboden’s new technology will
target projects between 500 kWe
and 3 MWe, which corresponds to a
steam output of 5-30 t/hr.
It is a market segment that is generally
too small for a cogeneration system
based on a single gas turbine.
And although microturbines could be
used, projects become complex if too
many are required.
“Gas turbines are almost not present
at this size,” noted Bertuzzi. “Internal
combustion engines are the
leading technology at this size. However,
although they give you about
40-45 per cent in terms of electrical
efficiency, you only get about 18 per
cent of steam. So, if you don’t need
hot water, you will lose 35-40 per
cent of the energy input. If you do
not need the power or hot water, this
is not the most suitable technology.”
With the new ORC technology,
heat is received at a higher temperature
than the 300°C used in its current
ORC for CHP biomass applications.
Normally this will deliver hot
water at 80-90°C, which is suitable
for low temperature cogeneration applications
such as district heating or
drying processes. The Steam & Power
ORC increases the system inlet
temperature to 400°C to deliver
steam at different pressures, ranging
from 6 bar up to around 18-20 bar.
Turboden first began developing
the technology two years ago,
analysing which applications required
large amounts of steam, little
electricity and little or no hot water.
It found that industries such as dairies,
food and beverage, paper,
chemical, textile, and oil & gas
could all benefit.
“We had all the components and
were confident we could move our
existing system technology to this
new higher temperature,” noted
Bertuzzi.
Through a research and development
project supported by the Italian
Ministry of Economic Development’s
Fund for sustainable growth,
Turboden designed a new ORC. The
new system is based on a modified
turbine, which uses a working fluid
that is suited to the higher temperature.
The company has a budget of
about €5 million to develop the
project.
The Rankine Cycle is a thermodynamic
cycle that converts heat into
work. Heat is supplied to a closed
loop, which typically uses water as
working fluid. The Organic Rankine
Cycle’s principle is based on a turbogenerator
working as a conventional
steam turbine to transform thermal
energy into mechanical energy and
finally into electrical energy through
an electrical generator. Instead of
generating steam from water, the
ORC-system vaporizes an organic
fluid, characterised by a molecular
mass higher than that of water, which
leads to a slower rotation of the turbine,
lower pressures and no erosion
of the metal parts and blades.
First developed in the 1950s, Turboden
believes ORC technology has
big potential, believing it can go
from the current approximately just
under 300 MW/year (of which 200
MW/year is in geothermal) to about
1 GW/year.
Speaking at a presentation earlier
this year in Brescia, Italy, Bertuzzi
said: “ORC for geothermal can go up
to 400-500 MW/year, taking market
share from steam turbines. Biomass
could also be 100 MW/year, easily.
And a market that has huge potential,
is waste heat recovery for processes
and oil & gas. This could be
an additional 200-300 MW/year.”
Development of the new ORC
system will help realise this potential.
According to the company, the
components in the new system are
the same as its existing cogeneration
technology but new materials
capable of withstanding the higher
temperatures are used.
“We have validated all the components
– we have selected and tested
all the materials. Therefore we do
not see any particular technological
risk to this new development. We are
used to designing units that run at
different temperatures – very low in
geothermal, medium in waste heat
recovery, higher in biomass.”
According to Bertuzzi, the new
technology could make more smallscale
industrial installations with
high steam requirements become
feasible. “To receive certain subsidies,
such as White Certificates, you
often need to comply with an overall
efficiency that is sometimes very
high. So if you don’t need hot water,
it is very difficult to meet these
overall efficiencies.”
With the possibility of receiving
subsidies, which support project
economics, payback times are impressive.
Looking specifically at the
dairy industry, where the first system
will be installed, Bertuzzi notes
that cogeneration systems are not so
widespread.
“Most of them buy power from the
grid and use gas fired boilers to produce
steam. Investing in a cogeneration
plant has a payback in the range
of less than three years. It depends
on the number of operating hours per
year, the size of the project and other
variables such as the price of the
electricity – the higher the electricity
price, the shorter the payback. The
cost of the gas is almost neutral because
you are already burning the
gas to produce the steam.”
The new unit at Centrale del Latte
Brescia will be used to produce 700
kW of electric power and 5 ton/h of
steam in the production processes for
milk pasteurization.
Although the boiler can be designed
to burn natural gas, biomass
or recover waste heat, the Centrale
del Latte Brescia installation will
use a natural gas-fired thermal-oil
boiler designed by industrial boiler
manufacturer Bono Sistemi - Cannon
group. The existing gas boiler at the
dairy will be kept as a backup.
The new thermal-oil, gas boiler is
not a conventional gas boiler that
produces steam to drive a steam turbine.
Instead it produces heat that is
transferred to a thermal oil loop. The
hot thermal oil evaporates the ORC
working fluid and the organic vapour
generated expands to the turbine,
which drives an electric generator to
produce electric power.
Downstream of the turbine, the organic
vapour pre-heats the organic
liquid in the regenerator and is then
condensed at high temperature releasing
its latent heat for steam generation,
to feed the manufacturing
process.
Delivery of the new ORC system is
scheduled in 12 months. As a skidmounted
solution, erection and installation
time is expected to be quite
short. This will see startup of the unit
at the end of 2019/start of 2020.
The owner of the unit is looking
forward to the benefits it will bring
to the operations. Dr Franco Dusina,
President Centrale del Latte di Brescia,
said: “Centrale del Latte is very
sensitive to clean and environmentally
friendly solutions; high efficiency
cogeneration fits perfectly with
our philosophy. For some years we
have been looking for a suitable
technology for our energy needs and
for improving the energy efficiency
of our production plant. We are sure
that the synergy between Turboden
and us, two important companies in
the industrial context of Brescia, will
lead to a successful project.
With this first project now firmly
off the ground, Turboden is already
targeting projects in other industrial
sectors.
Bertuzzi said: “One will be in paper
and the other is in chemical fibres.
We are also aiming to have our
first biomass project soon.”
In terms of the technology, Centrale
del Latte di Brescia is the first
of what Turboden calls a “multiple
size development” that will go up to
3 MWe and 25 t/h.
“We have a pre-design for four or
five sizes but the detailed design of
the larger sizes will be linked to the
first project. Typically, each pre-design
will validate the new size that
will come to the market. We hope to
conclude the development of the different
sizes within two years from
now,” said Bertuzzi.
Commenting on geographic markets,
he says the solution can be very
attractive for all markets where cogeneration
is either already best practice
or in the development phase. “It
depends on the price of electricity
versus the price of natural gas and
the presence of incentives to support
high efficiency cogeneration. We are
actively proposing this solution in
Italy, UK and Ireland but will also be
looking at other countries.”
To support the roll-out of the technology,
in addition to offering aftersales
services such as remote monitoring
and diagnostics, Turboden will
also be looking at how it can support
with financing installations.
Bertuzzi concluded: “In the cogeneration
sector, most of the time customers
are not eager to invest directly
in a project but are used to
having access to off-balance sheet
solutions. With the support of financial
partners and energy service
companies, or even directly, we are
available to study the best rental or
energy service scheme or leasing facility,
according to the customers’
preference.”
Milking the ORC
The gas-fired thermal oil
boiler generates heat that
is transferred to a thermal
oil loop. The hot thermal
oil evaporates the ORC
working fluid and the organic
vapour generated expands
to the turbine to produce
electricity. Downstream
of the turbine, the organic
vapour pre-heats the organic
liquid in the regenerator
and is then condensed at
high temperature releasing
its latent heat for steam
generation
Pasteurisation in milk production will be a prime application for the
new high temperature Organic Rankine Cycle technology