NOTE: Restrictions are in place to limit access to one or more of the files associated with this item. Authorized users must log in to gain access. Non-authorized users do not have access to these files.
Visit the Energy Systems Laboratory Homepage.
Revamping Pre-Heat Trains for Energy Saving
MetadataShow full item record
In this paper we look at the principles underlying the revamping of pre-heat trains to save energy through increased heat recovery. For brevity, we do not consider throughput changes. Only pre-heat train performance is considered. The interaction between pre-heat train and crude oil distillation column performance is considered elsewhere. The principles underlying the design of new pre-heat trains are also considered elsewhere. That study shows that that pre-heat trains differ from general heat recovery networks in four important respects: (i) The heat demand is dominated by a single 'cold' stream; (ii) Rather than having a distinct 'pinch point', the composite curves are often close over quite a large region; (iii) The heat demand can be broken up into two or three distinct processing regions and the temperatures of these divisions are fixed and more significant than the 'pinch point' itself; (iv) The rate of fouling encountered in pre-heat train exchangers is dependent upon crude oil velocity and exchanger wall temperature. This means that the 'pinch technology principle' of matching the hottest hot stream with the cold stream at its hottest point, first proposed by Ponton & Donaldson, does not necessarily apply with pre-heat trains. When it comes to revamping projects, pre-heat trains differ from general problems in other important aspects. The first is that pressure drop considerations are very important. The pumps used to drive the crude through the train are very expensive. The designer will therefore seek to achieve the targets without pump replacement. Pressure drop is very strongly affected by fouling and allowance will have been made for this in the pump specification. There is, as shown below, a need to consider the hydraulic effects of fouling during retrofit projects. Finally, exchanger technologies which mitigate fouling are becoming established and should be considered during revamp design.
SubjectPre-heat Train Revamping
Yeap, B. L.; Wilson, I.; Pretty, B.; Polley, G. T. (2002). Revamping Pre-Heat Trains for Energy Saving. Energy Systems Laboratory (http://esl.tamu.edu). Available electronically from