Any pulp mill owner knows that energy is the third largest cost in production behind materials and labor. What they might not know is that evaporators are the biggest energy users in the pulp mill. About 40% steam needed per ton pulp goes to the evaporators. Older evaporators need about 33% more steam for the same amount of evaporation and produce less reusable condensate, leading to higher fresh water usage.
88% of pulp lines in North America are more than 30 years old and for evaporators, the average age is 40 years old. Many older mills have at least two evaporator trains, while newer ones are able to achieve five times the capacity with only one train. As evaporators age, the operating and maintenance costs continue to rise and efficiency falls.
The mills that will survive in the long run are the ones who can control their cost of production by limiting water and energy usage while maintaining evaporator efficiency. The best way to achieve this may be to undertake an evaporator rebuild and upgrade. By adding heating surface and upgrading condensate segregation, an upgraded evaporator plant can provide improved steam economy, a dry solids increase and an overall increase in capacity. The performance of an evaporator is directly linked to the mill water usage. An upgraded one produces clean condensate that can be reused in the mill process reducing the need for fresh water. This lowers costs and environmental impact.
Valmet is the market leader for evaporation equipment for chemical pulp mills, both for new trains and upgrades to existing trains. Upgrades are a good way to achieve improvement in performance that come close to what new train can achieve, but at a lower cost and making use of existing infrastructure. To find out more about how Valmet can upgrade and rebuild your evaporator, contact us today.