(133c) Energy Integration - a Fresh Look for a Changed Energy World

The fundamental world shift in energy prices has a structural basis, and leading industry analysts are forecasting a long term oil price above $40/bbl. At the same time, environmental pressure to reduce CO2 emissions is growing steadily. Consequently the incentive to invest in technology to reduce energy consumption in process and energy plant has also fundamentally shifted, and a fresh look at capital schemes for energy conservation is warranted. However, this is against a background of the ?low hanging fruit' energy schemes having already been ?plucked' over the last 10 years.

Consequently there are two strategic directions in which it is logical to look for new energy projects. The first is to look to new ideas for heat integration schemes between adjacent processes and sites. An example is the use of refinery waste heat to evaporate LNG, substituting fuel firing in the LNG terminal's vaporisers. M W Kellogg Ltd. has developed a study and design methodology for such schemes and demonstrated their economics. The approach and results are presented in outline, and implementation issues discussed against the background of the operational difficulties perceived independently by the two centres.

The second strategic direction is to re-visit those ?old' ideas which in the past have been discounted on the grounds that they were uneconomic, but which in the new energy world could pay out. These can be given added incentive by adding new design ideas. Examples include the use of heat pumping in above-ambient distillation schemes, and some dividing wall column applications. A worked example is presented in which heat pumping and use of a dividing wall column for C4 isomer separation are re-visited as energy-saving alternatives.