Debottlenecking Debottlenecking: Exploiting Opportunities to Boost Performance
The goal of debottlenecking is to increase production capacity at an existing plant by making modifications to the equipment configuration or workflow. This is accomplished by eliminating bottlenecks that limit throughput. It can be an extremely profitable exercise for users, because in most cases debottlenecking adds extra capacity at a fraction of the cost of new build or expansion. PROCESS has put together some practical examples.
Retrofit, revamp and debottlenecking take place repeatedly over the course of a 40–50 year chemical plant lifecycle. Debottlenecking in particular provides a way of reacting quickly to evolving markets by significantly increasing capacity. To cite one example, special chemicals manufacturer Lanxess is increasing Mesamoll production in Krefeld-Uerdingen in response to rising demand for phthalate-free plasticizers. An investment in the mid single-digit million euro range is sufficient to expand capacity by 40 percent. The debottlenecking project will also include a significant amount of retrofit work, for example installation of new heat exchangers and reaction boilers.
Another successful project is underway at VTU. An ultrafiltration system is used to filter fermentation mash on a pharmaceutical production line. To avoid product degradation and maximize overall yield, this process step has to take place at low temperature, making filtration difficult. However, the filtration temperature must also not fall below a certain minimum threshold, because otherwise proteins precipitate out which impairs the permeability of the membrane and increases filtration time. The goal of the debottlenecking project is to reduce filtration time and increase overall yield.
After reviewing of a number of options, the engineers decided that changing the ultrafiltration system from batch to continuous mode was preferable to increasing the membrane size and incurring the higher investment costs. The four-loop system was converted to continuous mode. The concentration and diafiltration factors can be adjusted in each loop by measured addition of demi water. This operating mode has the advantage that the dwell time of the fermentation mash, which is continually fed into the ultrafiltration system, decreases significantly. Furthermore, in contrast to batch mode, the product concentration in the filtrate can be held constant. Overall yield increased by 16 percent, surpassing the original goal of 10 percent by a considerable margin.