Improving efficiency of the evaporation process to reduce greenhouse gas emissions at the Kwidzyn mill

Project Description

Modernisation of the evaporator plant at International Paper’s Kwidzyn mill in Poland began in 2015 and was completed in March 2018. The project originated as an internal cost reduction initiative, combined with International Paper’s continuous commitment to reduce greenhouse gas emissions.

The project aims to reduce steam consumption in the evaporation process, and increase the overall efficiency of the process.
The upgraded and newly designed equipment allowed us to achieve better steam economics, as well as higher dry solids capacity of black liquor – the main fuel in the recovery boiler.
An innovative concept assumed that we would remove more water at the evaporator stage, rather than doing it directly in the recovery boiler. A reduced feed of water mixed with fuel into the recovery boiler significantly improves the overall efficiency of the process, and increases heat generation from carbon-neutral fuel (black liquor), allowing us to replace corresponding volumes of coal.

The project team faced three major challenges. The first was design, where an error was only spotted during start-up. The second arose from the very short time for the implementation, and lack of space for configuration changes within the massive number of pipelines. The last challenge was to optimise and stabilise the new process to reach the target parameters, which took more than two months.

Project Purpose

The main purpose of the project was to decrease fossil fuel consumption and subsequently CO2 emissions at the Kwidzyn mill. To reach this goal two major changes were introduced to the evaporation process:

  • Debottlenecking of vapor line
  • A brand new concentrator to boost dry solids of black liquor

Project Evaluation

The annual savings come from:

  • Less heat used in the evaporation process – about 300,000 GJ/year
  • Additional thermal green energy from the recovery boiler – about 190,000 GJ/year;

Together this allows a reduction in coal consumption by 25,000 tonnes a year.

Martin Figacz 

Energy Plant Manager

At International Paper we continuously work to reduce our environmental footprint. At the power plant, we focus on how to reduce our manufacturing emissions and improve air quality.
We go beyond what EU regulations require, and look for continuous improvements in operations, upgraded equipment and fuel substitution. Reducing the volume of fossil fuel at our facility has an immediate positive effect on operating costs and emissions of greenhouse gases and other air pollutants. Our strategy and the thinking behind it led us to evaluate improvement projects like the one we completed in March.

We have worked on this idea for the past three years, and in the end the modernisation of the evaporator allowed us to make a step change related to black liquor dry solids used in the recovery boiler. Combined with improved efficiency and economics of the evaporation process, this resulted in another significant reduction of coal consumption and GHG emissions at our mill. Personally, I am very proud of this achievement.


Main Features

CO2 Emissions saved (tCO2)

52,000 tonnes/year


$6.5 million

Other projects