محمد بهبهانی
04-10-2013, 11:57 AM
a b s t r a c t
Process intensification in distillation led to major developments, such as reactive distillation, heatintegrated
distillation, cyclic distillation, as well as Kaibel and dividing-wall column. Still, the separation
of aromatics at industrial scale is carried out typically in a series of conventional distillation columns, with
severe penalties on the associated plant footprint, investment and operating costs. To solve this problem,
this study investigates novel separation alternatives powered by dividing-wall column (DWC) and Kaibel
distillation column. The new sequences using process intensification are able to separate five products
(lights, benzene, toluene, xylene and heavies) at high purity levels, in only two distillation columns.
AspenTech Aspen Plus® was used as a computer aided process engineering tool to perform the rigorous
simulation and optimization of the new separation alternatives, applied to a simplified industrial case
study. In order to allow a fair comparison, all design alternatives were optimized using the sequential
quadratic programming (SQP) method.
Notably, the novel design with two consecutive DWC units reduces the energy demand by 14%, while
the alternative combining a conventional stripper with a Kaibel column leads to over 17% energy savings
as compared to the conventional direct distillation sequence. Moreover, the new separation schemes
require less equipment and a reduced plant footprint.
a r t i c l e i n f o
Article history:
Received 2 December 2011
Received in revised form 10 April 2012
Accepted 24 June 2012
Available online 1 July 2012
Process intensification in distillation led to major developments, such as reactive distillation, heatintegrated
distillation, cyclic distillation, as well as Kaibel and dividing-wall column. Still, the separation
of aromatics at industrial scale is carried out typically in a series of conventional distillation columns, with
severe penalties on the associated plant footprint, investment and operating costs. To solve this problem,
this study investigates novel separation alternatives powered by dividing-wall column (DWC) and Kaibel
distillation column. The new sequences using process intensification are able to separate five products
(lights, benzene, toluene, xylene and heavies) at high purity levels, in only two distillation columns.
AspenTech Aspen Plus® was used as a computer aided process engineering tool to perform the rigorous
simulation and optimization of the new separation alternatives, applied to a simplified industrial case
study. In order to allow a fair comparison, all design alternatives were optimized using the sequential
quadratic programming (SQP) method.
Notably, the novel design with two consecutive DWC units reduces the energy demand by 14%, while
the alternative combining a conventional stripper with a Kaibel column leads to over 17% energy savings
as compared to the conventional direct distillation sequence. Moreover, the new separation schemes
require less equipment and a reduced plant footprint.
a r t i c l e i n f o
Article history:
Received 2 December 2011
Received in revised form 10 April 2012
Accepted 24 June 2012
Available online 1 July 2012