Abstract
C5 fraction, which accounts for 15-25% in naphtha, consists of molecules such as isoprene (IP), pentadiene (PD), cyclopentene (CP), and cyclopentadiene (CPD) can be used to manufacture petroleum resin and other high value-added products. Yet it is often burned as fuel and not fully utilized because separation of these products with close boiling points is difficult. One common process is to react CPD itself to form high boiling dicyclopentadiene (DCPD) so that it can be separated from the other C5 molecules. In addition, extractive distillation is also used to recover alkynes from light ends. Such a process involves the use of multiple separation columns and reaction zones. Furthermore, it is found that the reactor is highly coupled with one of the separation columns by two recycle streams which may lead to snowball effect and difficulty in control. Hence a wide range of opportunities for process integration and intensification is available. We find that the entire process with reaction and separation can be substantially simplified by reducing the number of reaction zones from 2 to 1 and number of columns from 8 to 6. Such a simplification increases not only process operability but also product concentration of DCPD from a range between 85wt% and 92wt% to at least 98wt%, while maintains the high purity (>99.75 wt %) for the IP stream and specified purity (>89.90 wt %) for the PD plus CP stream. In addition, capital cost can be greatly decreased for the simplified process. This process can be further intensified by using thermal coupling and external heat integration. Much energy saving can be achieved for the intensified process. Simulation results demonstrate that the proposed simplified and intensified process can substantially reduce capital cost, operating cost as well as improve process operability for the separation of a C5 mixture.