Integrated Process Design and Control: Novel Applications in Energy and Environment

Integrated Process Design and Control: novel applications in energy and environment

Sharifzadeh Mahdi[1] , Thornhill Nina F., Shah Nilay.

Centre for process Systems Engineering (CPSE), Imperial College London.

Process design and control share important decisions. When the process specifications are decided there is little room left to improve control performances. Therefore, it is highly recommended that process design and control design should be considered simultaneously. A systematic framework is needed to automatically generate alternative design and control solutions and screen them based on various competing/conflicting economic and control objectives. Such a systematic framework conforms to mixed integer optimization programming under uncertainty.

The challenge is that the integrated approach often leads to large-scale highly-combinatorial mathematical formulations which pose significant challenge for current optimization technology. This presentation provides an overview of our recent endeavours [1-8] at Centre for Process Systems Engineering (CPSE), Imperial College London, for research into integrated design and control of industrial processes. The research objective is to reduce the problem complexity and apply the methodology to challenging problems with energy and environmental applications.

We introduce a methodology for complexity reduction from Integrated Process Design and Control (IPDC) based on the notion of perfect control and process model inversion. Here, the treatment is based on the property that the inverse solution of process model can be used for evaluating the best achievable control performance. We argue that the resulting optimization framework benefits from several desirable properties. Firstly, the complexities associated with control parameterization are disentangled from the problem formulation. Secondly, simultaneous optimization of the control structure and process economy results is self-optimizing properties. Finally and most importantly, the steady-state and dynamic formulations of the so-called inversely controlled process model (ICPM) ensure steady-state operability and functional controllability, respectively.

We demonstrate the application of the proposed methodology using several novel applications including integrated design and control of two-series heat-integrated reactors [2], an ETBE reactive distillation [3], retrofitting an existing NGCC power plant using a solvent-based capture process [5], a liquefied natural gas (LNG) production plant [6], a micro-reactor for autothermal reforming of methanol [7] and integrated operation of renewable energy systems [8]. The features of interest include flexible operation of aforementioned processes under uncertain scenarios such as external disturbances or load reduction. Furthermore, the applied optimization solution algorithms to implement the proposed methodology are elaborated and discussed.      

References

[1] Sharifzadeh M^*, (2013). Integration of process design and control: a review, Chemical Engineering Research and Design, 91 (12), 2515–2549 (Link).

[2] Sharifzadeh M^*, Thornhill NF, (2013). Integrated design and control using a dynamic inversely controlled process model. Computers & Chemical Engineering, 48, 121–134. (Link)

[3] Sharifzadeh M^*, (2013). Implementation of an inversely controlled process model for integrated design and control of an ETBE reactive distillation, Chemical Engineering Science. 92, 21–39. (Link)

[4] Sharifzadeh M^*, Thornhill NF, (2012).Optimal selection of control structures using a steady-state inversely controlled process model. Computers & Chemical Engineering, 38 (5), 126–138. (Link)

[5] Sharifzadeh M^*, Shah, N, (2015). Integrated retrofit and operation of solvent-based capture plants and natural gas combined cycle (NGCC) power plants: solvent performance comparison at industrial scale (invited paper, under review at AIChE Journal)

[6] Sharifzadeh M^*, Park J, Shah N, (2015). Integrated design and operation of liquefied natural gas plants: a case study, (in preparation).

[7] Sharifzadeh M^*, Sempou A, Shah N, (2015). Integrated design and operation of intensified processes: autothermal reforming of methanol using micro-reactors, (in preparation).

[8] Sharifzadeh M^*, Lubiano H, Shah N, (2015). Integrated design and operation of renewable energy systems under variable electricity load scenarios, (in preparation).

---

1 Corresponding author, Email: mahdi@imperial.ac.uk , Address: Room C603, Roderic Hill Building, Centre for Process Systems Engineering (CPSE), Department of Chemical Engineering, Imperial College London, South Kensington, London SW7 2AZ, UK.