Normally suitable for capacity increase up to 30%, with focused and effective operation. It is based on maximum use of the existing equipment, leaving the main process line as much as possible unchanged.
Applicable technologies are:
- Primary Reformer upgrade
- Heat Exchange Reformer (TPR)
- Partial Oxidation Reactor (POx)
- Isothermal Methanol Converter (IMC™)
Central to Casale approach to revamping is the use of technologies specifically devised for this purpose, whose effect is increasing the efficiency of existing units, as opposite to simply replacing existing inefficient equipment or adding new ones (“add-on” approach). Casale revamping philosophy is always to enhance the performances of the existing plant by conceiving more efficient process flow configurations or by installing high efficiency equipment.
In order to increase the production of the synthesis gas the following strategies can be followed:
- Prereformer installation: it allows the primary reformer to process additional natural gas without any alteration. So it is particularly useful when no modifications can be made to the primary reformer.
- Primary reformer upgrade
- Partial Oxidation: a new section is based on a POX (partial oxidation) reactor where natural gas reacts in presence of oxygen without catalyst is added in parallel to existing traditional reformer
In order to debottleneck the loop, existing adiabatic converter can be revamped to isothermal technology using Casale IMC (Isothermal Methanol Converter). Another way of processing a higher flow of make-up gas is to install an additional converter on the make-up gas line, which the so-called "once-through" reactor. Steam raising IMC is particularly suitable for such operation.
The Distillation Section revamping options have to be evaluated to comply with the increased methanol production from the reaction section. In case the columns are not suitable for the new load, it is typical to revamp the columns internals with high efficiency trays.