Process modularization is an alternative process design
and construction
framework, in which modular units are independent and replaceable
blocks of a process system. While modular plants have higher efficiency
and are safer to construct than conventional stick-built plants (Roy,
S. Chem. Eng. Prog. 2017, 113, 28–31), they are significantly more challenging to operate
because of the loss in the control degrees of freedom that comes with
process integration and intensification (Bishop, B. A.; Lima, F. V. Processes
2021, 9, 2165).
To address this challenge, in this work, operability analyses are
performed to consider the design and operation of modular units. Initially,
a steady-state operability analysis is employed to find a set of feasible
modular designs that are able to operate considering different modular
plant conditions. A dynamic operability analysis is then applied to
the feasible designs to identify the operable designs that are capable
of rejecting the operational disturbances. Lastly, a closed-loop control
measure is introduced to compare the performances of the different
operable designs. The proposed approach is implemented in a modular
membrane reactor to find a set of operable designs considering different
natural gas wells, and the respective closed-loop nonlinear model
predictive control performance of these units is evaluated.