Paper Technology International 2020 - Journal - Page 103

PAPERTECHNOLOGYINTERNATIONAL
Once started up, the sulfuric acid plant will help Klabin
control the sodium and sulfur balance of the mill and will also
improve the resource efficiency as less sulfate needs to be
discharged due to the optimized Na/S balance. Major savings are
achieved by reduced spending on chemicals, not only on sulfuric
acid, but much more importantly, in reduced consumption of sodium
make-up chemicals. The WSA plant also reduces the environmental
footprint by reducing the need for purge streams containing sulfur
and sodium.
There are also outside logistics advantages, “Sulfuric acid
is used widely at the mill site to control pH in several parts of our
process, and the amount we use is actually quite huge,” adds
Razzolini. “But this is not only about sustainability and economics;
there is also a major logistics issue with transporting some five or six
hazardous chemical trucks from 500 km away to the mill site, every
day.”
When all the sulfuric acid needed by the mill is produced
internally, only elemental sulfur will need to be transported to the
mill. The elemental sulfur volume represents one third of the sulfuric
acid volume, and it is used only to supplement the sulfur flow in
CNCG gases. Therefore, transport is reduced by as much as 85%,
with the added advantage of the transported elemental sulfur not
being a hazardous substance.
Sulfuric Acid Production – Learning Curve?
The Ortigueira mill will soon be 100% self-sufficient in
sulfuric acid, which makes the mill a major chemical producer
as well as a pulp producer. What is there to learn about the new
process? Razzolini says, “At the site we generate oxygen, sodium
chlorate, which generates hydrogen, used in the lime kiln. Chlorate
is converted to chlorine dioxide. We also handle elements inside the
cooking and evaporation process, as well as separate methanol,
turpentine, and tall oil. In fact, there is actually a long list of what we
already do, and we are very much heading in the direction of a true
biorefinery when it comes to side streams generated from the mill.”
Razzolini adds, “Obviously in the case of the sulfuric acid
plant, we are talking about a very corrosive material that is difficult
to handle and we have to have a very high level of safety involved
in all the operations, as we already do mill-wide. This safety priority
has been at the top of our agenda when it comes to the sulfuric acid
plant.”
“We have partnered
with ANDRITZ for
many years at Klabin,
developing a lot of
projects, initiatives,
and technologies.”
FRANCISCO RAZZOLINI
Director of Industrial Technology,
Innovation, Sustainability and
Projects.
101

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