Chemical processes must now use as little energy as economic and practicable to:
- reduce operating costs
- prevent the build-up of carbon dioxide in the atmosphere from burning fossil fuels
- preserve reserves of fossil fuels.
But how can we achieve the highest levels of energy efficiency, minimize our costs and fulfill society’s aspirations for sustainable activity?
Opportunities to Improve the Energy Efficiency
Most processes operate in the context of an existing site in which a number of processes are linked to the same utility system. The utility system converts fuels to steam, electricity and shaft power to satisfy the demands of the processes on the site. The utility systems of most sites have evolved over many years without fundamental questions being addressed as to their design and operation. Because utility systems are subject to much uncertainty of operation across the site, there is usually significant redundancy in place.
This redundancy allows the site to respond to changes in the operation across the site, for maintenance of equipment and for breakdown. Maintaining the integrity of site operation is important, but the penalty is a significant amount of utility equipment redundancy.
However, this redundancy also presents opportunities to improve performance by managing its operation more effectively. Thus, utility systems offer the opportunity of substantial savings given their large investment requirements and operating costs. A variety of techniques can be applied to improve the efficiency of operation of existing systems at various levels of investment, starting from no capital investment at all.
The State-of-Art Approaches
Investigating improvements in energy integration of individual processes should begin by understanding the utility system that services the process. Only in this way can the true incentives to improve the energy performance of individual processes be established.
Thermodynamic techniques for heat exchanger network design and retrofit were developed in the 1980’s. These have proved to be extremely successful industrially. However, these methods also have significant drawbacks. This is particularly true when trying to improve the performance of existing processes in retrofit.
This problem was difficult to address using the thermodynamic methods developed in the 1980’s, since when they were applied to retrofit they effectively considered the problem as a pseudo new design.
To be effective, whatever approach is used should not attempt to move the design of an existing process towards an ideal new design, but to take account of what is existing. Significant improvements have been made to heat exchanger network design methods in recent years to parallel those in utility system design, both retrofit and new design.
Process Integration Ltd brings state-of-the art technologies to improve energy efficiency with solutions through software, training and consultancy that are tailored to meet the individual needs of companies