ANDRITZ SulfitePower sulfite liquor recovery boiler
ANDRITZ has done considerable development work installing sulfite boilers and chemical recovery units around the world to the point where it today has the best available technology. SulfitePower sulfite liquor recovery boilers enable the recovery and reuse of cooking chemicals in an environmentally safe way while generating significant energy for a sulfite pulp mill.
In the early 1900s, sulfite pulping was the dominant means of producing wood pulp. The process uses sulfites or bisulfites to extract lignin with a counter ion (base) of sodium, calcium, magnesium, or ammonia. Today, the sulfite process accounts for less than 10% of total chemical pulp production, but important grades such as dissolving and specialty pulps utilize the sulfite process.
The cooking liquor produced (called brown, red, thick, or sulfite liquor depending upon the application) has special characteristics that must be taken into account when designing the liquor recovery boiler. The first ANDRITZ sulfite boilers were installed in the 1950s, so the company has a long history and extensive experience. ANDRITZ engineered and delivered the world’s largest sulfite boiler and chemical recovery unit to South Africa.
SulfitePower boilers
SulfitePower boilers combust the organic content of the concentrated liquor and close the chemical cycle in the sulfite pulp mill. The process includes raw acid preparation and combustion of malodorous gases while adhering to even the strictest environmental regulations. As a result of the thermal conversion of pulping chemicals, pulp mills can be self-sufficient in meeting their internal energy demand.
The SulfitePower multi-stage chemical recovery system uses highly efficient subsystems for the separation of both water-soluble and insoluble materials. The scrubber is uniquely designed for this purpose and guarantees an excellent raw acid quality, which is the basis for high yield during sulfite pulp production.
SulfitePower benefits
ANDRITZ SulfitePower liquor boilers generate high-pressure steam while converting the main chemicals in the spent cooking liquor to cooking acid for reuse in the pulping process. This is accomplished at very high efficiencies and with low flue gas emissions. The boiler is designed for the additional integration and combustion of methanol, furfural, sludge (production waste), biogases, and gases with high SO2 concentrations (CNCG) or odorous High Volume Low Concentration (HVLC, DNCG) gases.
Sulfite recovery boiler (SulfitePower), at Sappi Saiccor, South Africa
Sulfite recovery boiler (SulfitePower). Tembec, Canada.
A multi-stage chemical recovery system uses highly efficient systems for the separation of both water-soluble and insoluble materials. The scrubber system is uniquely designed for this purpose and guarantees an excellent raw acid quality, which is the basis for high yield during sulfite pulp production.
The benefits of sulfite liquor boilers
ANDRITZ sulfite liquor boilers generate high-pressure steam while converting the main chemicals in the spent cooking liquor to cooking acid for reuse in the pulping process. This is accomplished at very high efficiencies and with low air emissions. The boiler is designed for the additional integration and combustion of methanol, furfural, sludge (production waste), gases with high SO2 concentrations, biogases, and odorous gases (HVLC).
