The need for evaporator upgrade may result from demand for higher pulp production or better energy efficiency, tighter emission limits or changes in the pulping process.

Rinheat supplies upgrades for:
  • Black liquor evaporators
  • BCTMP evaporators
  • NSSC evaporators

Rinheat has developed new technologies for upgrading black liquor evaporation plants including several patented evaporator designs. The upgrades are tailored for each site with thorough process and equipment design. ​3R Heat recovery systems are originally found in TMP mills all over the world and the new application clean steam production in modern biomass and bioproduct plants.​ Rinheat is an agile partner and has experience on both turnkey projects and equipment deliveries.​


The Customer wants to increase capacity without increasing steam consumption.


Introduction of an additional evaporation effect and more efficient surface condenser.


Multiple effect evaporation utilizes the pressure and temperature differences between effects to reuse the energy of primary steam as many times as possible. The Rinheat evaporators are designed to minimize pressure losses throughout the evaporation train and the countercurrent surface condenser allows final condensing temperatures even below 50°C. Adding an effect to a multiple effect evaporation train will allow a higher rate of evaporation for the same amount of steam, or, especially in the case of falling film evaporators, will deliver the same amount of evaporation for less primary steam.


The Customer is operating the mill against recovery boiler capacity and wants to increase pulp production capacity but is also suffering from fouling of equipment.


Increase firing liquor dry solids to reduce the relative amount of flue gases from combustion. Introduce full capacity washing.


If the flue gas side of recovery boiler is limiting the capacity, a solution to increase production is to reduce the amount of water in firing liquor. This will increase energy production and reduce the amount of flue gases. Rinheat OT (Outside Tube) concentrator can provide a solution for the fouling, since the viscous liquor is flowing on the outside of the heat exchange tubes, which makes it washable and non-plugging


A lot of capacity is lost for washing the equipment and need for washing increases with DS increase.


Rinheat full capacity washing and front end optimization.


Washing related losses can be many: First of all, it is always better to wash with weak liquor than condensate – this way, the equipment will be reducing water from the circulation instead of increasing the liquid amount.Secondly, to minimize the loss of production, the front end of the evaporation train should be organized so that the unit in washing can still be driven on full steam.The out coming washing liquor is returned to an evaporator effect corresponding to the dry solids concentration.