DEVELOPING NETWORK MODELS OF INDUSTRIAL SYMBIOSIS

Thérèse G. Lee Chan1, Venessa K.K. Bhagwat2 and David A. Janes3*

1,2,3Faculty of Engineering, The University of the West Indies, Trinidad

1Email: therese.lee@sta.uwi.edu

2Email: venessa.bhagwat@my.uwi.edu

3Email: david.janes@sta.uwi.edu *(Corresponding author)

Abstract:

This study aimed to examine whether industrial symbiosis (IS) could be applied on the Point Lisas Industrial Estate (PLIE) in Trinidad and Tobago for the reuse of process carbon dioxide (CO2) within the estate. To acquire optimal networks, initially simplified petrochemical complexes were posed as transportation-type problems and solved with linear programming and mixed integer linear programming techniques. Network models were developed in which process CO2 was optimally allocated between existing ammonia (sources) and methanol plants (sinks) on the PLIE. Multiple scenarios were considered including possible restrictions on CO2-transfers from sources or to sinks. The functionality of the developed network models was confirmed with three test cases. Multi-objective optimization (MOO) was applied to a fourth model, with a secondary objective of minimising operational network costs. In the second stage, an enterprise input-output (EIO) model was developed from both process engineering and economic data. It incorporated performance indicators, which had been proposed in the literature, to calculate the level of industrial symbiosis and benefits - based on “the three pillars of sustainability” - realized in the representative industrial network. On the representative petrochemical network, 17% of the process CO2 emissions were reused in chemical manufacturing and the eco-connectance, which is one measure of the level of IS, was determined as 1.33. This demonstrates the presence and level of IS in the industrial park. Furthermore, optimized flow networks were created, with and without a CO2-reusing propylene carbonate plant. MOO was used to determine how to add the CO2-reusing plant to the industrial network to minimize both CO2 emissions and implementation costs. The addition of a CO2-reusing plant reduced the CO2 emissions by 1.1%, demonstrating there is scope for improving the existing IS network.

 

Keywords: Industrial symbiosis, Carbon dioxide utilization, Multi-objective optimization.

https://doi.org/10.47412/ZXGG6891

 

 

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