Eka Engineering: The SVP process
The SVP process is one of Eka Engineering’s
most commonly built processes to generate
chlorine dioxide in large quantities.
Sodium chlorate is reduced by methanol in anacidic environment to form chlorine dioxidegas. The gas is then dissolved in water andused as a bleaching agent in the mill.
SVP-LITE®
Our large-scale, single-vessel processes (SVP) generate
chlorine dioxide in a vacuum environment and produce
a solid salt cake by-product. SVP-LITE® systems use
methanol as a reducing agent.

SVP-SCWThe SVP-SCW (salt cake wash) process is an add-on
option to the SVP-LITE process.
This is a preferred choice for pulp mills that want to further:• Reduce their salt cake by-product (approximately 25%)
• Lower their acid consumption (approximately 17%)

Benefits
The SVP process is an ideal
choice for pulp mills that look forthe below specifications:
Very high yield
High strength CIO2 water
Very fast reaction rate, 		minimum start-up and stoptime (few minutes)• Easy to operate (one stagereactor)• By-product CI2 reduced tonegligible level• Elemental chlorine free CIO2
produced.
• Suitable for larger capacities• Safe CIO2 (high operationvacuum – less risk for 		decompositions)•••

In addition to acid recovery, SVP-SCW features all thesame benefits as SVP-LITE.® It is possible to convert any
SVP process to another with appropriate equipmentchanges.
Main reaction
Our patented SVP-LITE® process generates chlorine dioxide (ClO2) by reducing sodium chlorate(NaClO3) using methanol (CH3OH or MeOH) in a sulfuric acid (H2SO4) solution, according to thefollowing reaction:
12 NaCIO3 + 3 CH3OH + 8 H2SO412 ClO2 + 4 Na3H(SO4)2 + 3 HCOOH + 9 H2O

The by-product of this reaction is an acidic salt cake, sodium sesquisulfate Na3H(SO4)2 that isapproximately 18 - 25 wt.% sulfuric acid. By recovering the sulfuric acid from the sodium sesquisulfate
salt, acid feed requirements and salt cake volume can be reduced by approximately 17% and 25%,respectively. Recovering this acid is the function of the salt-cake wash (SCW).

SVP- LITE® overview
The production of ClO2 in the SVP-LITE® process is based on the reaction between NaClO3 ,sulfuric acid (H2SO4), and CH3OH. The heart of the process is an all-titanium ClO2 generator, alarge vessel in which the NaClO3 is reacted to form ClO2.

The key feature of the SVP-LITE® process is the circulation of the main reactor vessel, which iskept under vacuum:
Reactants (chlorate, methanol and sulfuric acid) are fed to the reactor system where they react
to form chlorine dioxide and a salt cake by-product precipitates
2. Steam is added to the reboiler to evaporate water from the generator solution
3. Gas leaving the generator is a mixture of chlorine dioxide and water vapor, which is absorbed
into water in the absorption tower
4. The absorption tower tail gas is further scrubbed to avoid emissions
5. A side stream of the reactor solution is fed to the filter, which removes the salt cake by-product6. The reactor solution is returned to the reactor
7. Chlorine dioxide water from the absorption tower is transferred to storage tanks
8. An emergency stop interlock system is in place that will shut down the process should pressure,temperature or flow parameters operate out of range
1.

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