Practical Process Integration Retrofit Part 4. Handling Large Projects

Practical Process Integration Retrofit

Part 4.  Dealing with Large Projects

  G.T.Polley

The  “Cross-Pinch Method” is suitable for use in identify retrofits when the number of streams is small (the example used in the demonstration of this method had seven streams, Polley [2011]). However, “Pinch Technology” is based on the assumptions that capital cost expenditure is controlled by the cost of heat exchangers and factors such as network operability can initially be ignored. With small projects operability considerations are easily undertaken by an experienced process engineer as the revamp is developed. With large projects this is difficult. The evaluation of the capital cost of a revamp can often be dominated by the cost of piping a modification to “civils”. With small sized projects an experienced process engineer can incorporate a consideration of these factors as a network structure is developed. With large projects this is not possible.

The solution to this problem is to decompose large networks into a number of smaller self contained networks.

References

Tjoe T.N. & Linnhoff B. “Using pinch technology for process retrofit”, Chem.Engng., 1986 April 28, pp47-60

Ahmad S. & Linnhoff B. “Supertargeting: Different process structures for different economics”, ASME J.En.Res.Tech., 1989, 111(3), 131-136

Tjoe T.N.  Ph.D. Thesis 1986, UMIST, UK