Paper Technology International 2020 - Journal - Page 93

PAPERTECHNOLOGYINTERNATIONAL
Together with ANDRITZ burner solutions, Meva Energy and
RISE, a prototype multifuel burner was developed to be able to run
on standard fossil gas, in this case LPG, as well as Meva Energy’s
renewable gas. Meva Energy’s process engineers generated a
simulation of how different low-value feedstocks would affect the gas
quality and based on those requirements the burner was developed.
The burner was installed in combustion chamber that mimic the
combustion conditions at a tissue mill and then installed at Meva
Energy’s demo plant in Sweden.
The Meva Energy plant was adjusted so the gas could be
extracted at different points along the gas cleaning system. The
tests showed that the burner could easily switch between 100%
syngas to 100% LPG back, and forth and syngas from all the tested
sampling points could be combusted nicely.
Sofidel and Meva Energy to install renewable syngas plant at
Swedish mill
Following this, a study of the effects of introducing the
renewable syngas on the tissue drying system as a whole has been
conducted by ANDRITZ Novimpianti and the University of Pisa.
After successfully concluding this pre-project, Sofidel Sweden and
Meva Energy finally announced a commercial agreement specifying
the world’s first commercial use of renewable gas for fossil-free
tissue drying. The agreement means that Meva Energy will build
and operate a gas production plant at Sofidel´s tissue mill in Kisa,
Sweden and deliver renewable gas to Sofidel on a long-term
contract. The target is to commission the gas plant in mid 2023.
Negative CO2 emissions and potential of cost reduction
Switching to renewable Meva gas, it is estimated that
Sofidel´s Kisa mill will reduce its CO2 emissions by 8500 tons per
year compared with the carbon footprint of today’s consumption
of fossil LPG. The biomass used as fuel will be locally sourced
wood residue. The decentralized principle of on-site generation
in combination with not having to refine the gas to pure methane
is the basis for reaching a high conversion efficiency, as well as
realizing high levels of CO2 emission reductions. Based on this, the
Meva Energy technology can realize more substantial cuts of CO2
emissions than conventional types of biofuel. As the Meva Energy
system also produces biochar, a stable form of renewable carbon
that creates a carbon sink when used for soil improvement, the net
CO2 emissions can potentially even be negative.
The starting point for converting to a renewable solution is
sustainability, but of course, the economic aspect is of the utmost
importance when looking into replacing fossil gas in tissue drying
hoods; energy usage constitutes a considerable share of the cost
for a mill. Fossil gas is subject to a global market where the price
fluctuates dramatically, and the long-term forecasts clearly point
towards higher costs. During the last 18 months the costs for
European emission allowances have sky-rocketed from 18 EUR/tons
to over 60 EUR/tons. Few people think it has reached its top level
and there is strong political push towards an even higher emission
allowance price. What will the cost of combusting fossil natural gas
be a few years from now?
Figure 6: Combustion chamber representing conditions at
Sofidel.
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