Energy intensive industries are those that transform physica- or chemically the raw materials into final products, utilizing huge amounts of energy per unit produced, for example, cement, iron & steel, petroleum refining, chemicals & petro-chemicals, metal casting, glass, mining, aluminum and forest products. These industries are able to reduce their sustainability gap by developing in their business models an industrial ecology approach.
According to Erkmann, there are four strategies that could be applied for their sustainability management: to turn the by-products into economic products, to minimize waste effluents, to increase production efficiency (“doing more with less”) and to decarbonise the energy supply. (Erkman, 1998)
These strategies could be implemented in three different scales:
Macroscopic: It’s about reducing the material and energy flows in the whole economy in a local, national or global level
Mesoscopic: it’s about minimizing waste generation in a production unit by improving processes.
Microscopic: it’s related to production optimization at molecular level by finding alternative chemical reaction routes, for example, the green chemistry
Nowadays, turning the by-products into economic products in a regional or local scale is acquiring importance; actually some countries have introduced these principles in their laws, specifically, the case of Switzerland, Belgium and China. (Tubiana, 2011)
To do it a reality, it would be necessary to take into account complex consideration on product and process design, such as the economics and optimization.
First, an inventory of all the industry players in a region, such as their waste treatment and management needs should be done. That means, doing the flux inventory and sensitize the stakeholders about sorting and mutual waste collecting.
A tool which is able to support the assessment of industrial ecosystems design is the Chemical Process Simulation (CPS); it has been used for modeling multiple industrial processes from different companies, so it can assist project developers in order to evaluate the environmental impacts and the economical benefits of developing a byproducts exchange network (Casavant, 2004).
A trouble which may be found using this tool is the data quality; by doing the inventory of the different process streams, it has been found disparities on the sorting practices (companies sort according to their priorities) and different measurement units (m3, tons, numbers…) (Pôle Synéo, 2011). These disparities increase the uncertainty of process models, so data collection from companies and assumptions must be done in detail.
Then, an evaluation in comparison with the “business as usual (BAU)” scenario is needed, because waste valorization may require transportation and an intermediary treatment process which might have deeper environmental impacts.
Finally, Developing a byproducts exchange network could take time depending on the grade of complexity, for this reason, the synergies between industries may be prioritized in short, medium and long term.
In summary, external waste valorization will reduce the sustainability gap in many process industries by utilizing process simulators for certificating its technical feasibility. By the other side, an economic and risk evaluation is necessary to be performed.
Sources:
Erkman Suren. Vers une écologie industrielle. Charles Léopold Mayer Editions. Switzerland 1998 pg 100
Casavant, Tracy E. et al. Using chemical process simulation to design industrial ecosystmes. Journal of Cleaner Production 12. Canada 2004. Pg 901 -908
Pôle Synéo. www.polesyneo.eu Consulted on September 12th, 2011
Tubiana, Fabian. L’écologie industrielle cherche partenaires. Environnement Magazine No 1697. France May, 2011. Pg 22- 26
