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School of Chemical Engineering and Analytical Science

Process integration technology reduces greenhouse gases

The production of chemicals - from fuels to commodity polymers - is energy-intensive and costly. But production costs and greenhouse gas emissions are now falling following research at the Centre for Process Integration. New modelling and software tools based on methods collectively known as 'pinch technology' identify cost-effective efficiency savings in chemical processing; chemical companies around the globe have used the software to make production more sustainable - and cut their fuel bills by hundreds of millions of dollars.

In the face of climate change and diminishing fossil fuel reserves, companies large and small are all looking for ways to save energy. Driven by new environmental legislation, stringent regulation and soaring energy prices, the search for more sustainable energy use and efficient manufacturing is intense.

Sunlight appearing through the clouds

The chemical manufacturing sector is no exception. Indeed, chemical processing plants consume vast quantities of energy as they mix and heat raw ingredients and control reactions to make the commodity chemicals that supply the rest of the manufacturing sector.

Working with 13 industrial members as part of the Process Integration Research Consortium (PIRC), the Centre for Process Integration (CPI) developed computer modelling methods, known as 'pinch technology', which help chemical engineers to improve energy efficiency during chemical manufacturing and processing. CPI developed six software tools, each focusing on different aspects of chemical production: heat recovery systems, utility systems, distillation systems, cryogenic systems, water integration and refinery modelling and optimisation.

"Research by the Centre for Process Integration makes refineries and chemical processing plant more energy efficient - significantly reducing CO² emissions and production costs."

Robin Smith / Professor of Chemical Engineering
30+ consultancy projects icon

Software

Software used in more than 30 consultancy projects.

Following the research phase, spin-out company Process Integration Ltd (PIL) refined the software and developed it for commercialisation. Licences have now been sold to 14 different chemical manufacturing companies worldwide. PIL has also used the software internally for over 30 consultancy projects.

The Chinese petrochemical corporation Sinopec today enjoys a sizable annual cost savings from process improvements identified by the PIL software. For example, Sinopec used the software to design and build cost-effective retro-fitted heat recovery systems in some of its plants.

Consumption

Chemical processing plants consume vast quantities of energy as they mix and heat raw ingredients and control reactions to make the commodity chemicals that supply the rest of the manufacturing sector.

The Manchester software is also used to simulate plant utility systems that provide power and steam for many chemical processing steps. These simulations help operators to optimise the utility systems without additional capital expenditure; Sinopec has saved further simply by deploying its utility systems more effectively.

PIL has conducted many studies on behalf of Sinopec, using the expertise of its 50 employees and its software products. The systematic methods, powerful mathematics and simple graphical outputs developed by the CPI research allow PIL consultants to provide petroleum companies with insights into how they can improve their refinery hydrogen networks.

Molecular modelling of refinery processes by CPI, in collaboration with PIL and Sinopec, has led to the development of a new software system that will help to improve the efficiency of crude oil processing. Sinopec has validated the new software at two refineries and PIL is in the process of finalising the package for market launch.

Background

The Centre for Process Integration focused its research in four distinct areas of chemical manufacturing: heat recovery, utility systems, refinery hydrogen networks and refinery molecular modelling.

The team developed new approaches to heat exchange design that combine mathematical modelling with thermodynamic analysis. By understanding the principles that limit existing heat recovery systems, CPI was able to develop simulations to identify cost-effective improvements by considering process improvements in parallel with retrofitted heat recovery systems.

CPI's modelling of utility systems looked at the part-load performance of equipment as well as the optimisation of the total system. The models have been used to design more efficient utility systems and to improve the operations of existing systems without requiring any additional capital expenditure.

Oil refineries use and produce hydrogen gas which is circulated through the plant through its hydrogen network. The CPI researchers were the first to model the complex production, consumption and disposal of hydrogen; they used the models to systematically analyse these complex interactions and explore their influence on the profitability of the refinery. The CPI software integrates mathematical optimisation methods and graphical outputs to help process engineers work out the minimum hydrogen supply for a network, screen hydrogen purification processes and control the hydrogen network with maximum efficiency.

Finally, the Manchester researchers embraced the challenge to model refinery processes at a molecular level, a task previously thought to be far too complex. However, the team was able to relate the bulk properties of different streams to the molecular make-up of stream components - a breakthrough that made molecular modelling possible. Molecular modelling now makes it possible for refinery operators to manage the flow of specific molecular species through the refinery which helps them to extract more value from crude oil and increase profitability.

The team

Funders

  • Process Integration Research Consortium (PIRC)

List of references

  • X X Zhu, N D K Asante “Diagnosis and Optimization Approach for Heat Exchanger Network Retrofit”, AIChE Journal, Vol. 45, No. 7, pp. 1488-1503 July (1999). (34 citations)
  • P Varbanov, S Perry, Y Makwana, XX. Zhu and R Smith, “Top-Level Analysis of Site Utility Systems”, Chemical Engineering Research and Design, 82 (A6): 784-795 (2004). (27 citations)
  • Joao J Alves, Gavin P Towler, “Analysis of Refinery Hydrogen Distribution Systems”, Industry Eng. Chem. Res. 2002, 41, 5759-5769). (163 citations)