Eco-efficiency assessment; Production of bleaching chemicals for the Elemental Chlorine Free, ECF, pulp industry - A Case study at Eka Chemicals (AkzoNobel Pulp and Paper Chemicals)

Abstract

Sustainable development embraces three dimensions and main areas; economic growth, social progress and ecological aspects. Eco-efficiency assessment is a business tool which can be used in order to compare two or several products, processes, activities or plants from an environmental and cost perspective. The tool is one way for companies to include sustainable development when it comes to future strategic decision making. Eka Chemicals is a business unit within AkzoNobel mainly producing and supplying chemicals and know how to the pulp and paper industry. The company is applying eco-efficiency assessments in order to learn more about their products and introducing lifecycle thinking in their organization. The main objective with this thesis is to investigate the feasibility of developing a flexible model of alternative production systems and transfer it into Eco-efficiency assessments. A case study at Eka Chemicals acts as the basis for the thesis and it focuses on production processes for bleaching chemicals used by the ECF pulp and paper industry. A second objective is to increase the understanding of the bleaching chemicals production systems in terms of environmental and economic performance. Based on assumptions about; (1) the geographic location of the production and (2) system properties decision making at Eka can affect, four different production systems are compared in terms of eco-efficiency; (1) SVP-LITE, (2) SVP-SCW, (3) chemical island and (4) integrated plant. It was found feasible to develop a flexible model for Eco-efficiency assessment. In the approach chosen, the systems are divided into background systems and foreground systems. Scenario analysis is applied and the scenarios are designed to distinguish background system properties from foreground system properties. This methodological choice makes it possible to identify important parameters and assumptions that affect the overall performance of the systems investigated. It further structures and speeds up the procedures since the assessment can focus on a certain part of the system at a time. The alternative production systems studied show significant differences regarding the environmental impact dimension. When it comes to the economic dimension, it is not possible to differentiate and rank the alternative production systems by use of an eco-efficiency diagram. The most important conclusion of the case study is that the assumption regarding how the electricity used for producing the bleaching chemicals, on the pulp mill site or elsewhere, is crucial for the ranking of the production systems compared. The chemical island is more eco-efficient if the electricity used is produced from biomass. When Russian electricity grid mix is used, the SVP-SCW scores best with regard to eco-efficiency. It is further concluded that the geographical location of the production of ECF- pulp bleaching chemicals is a key parameter when trying to find the most eco-efficient alternative. The choice of producing sodium chlorate on-site or not is also an important parameter affecting the eco-efficiency of the production systems. Since transportations have a small influence on the eco-efficiency, the sodium chlorate is produced preferably off-site and transported to the pulp mill if the electricity system for onsite production is characterized by fossil fuels. If the on-site electricity system includes a large share of renewables, on-site production of sodium chlorate is preferred.