(164b) Integrated Modelling and Optimization of Refinery Hydrogen Networks

INTEGRATED MODELLING AND
OPTIMIZATION OF REFINERY HYDROGEN NETWORKS Blessing Umana^a,
Nan Zhang^a*, Robin Smith^a

a Centre for Process
Integration, School of Chemical Engineering and Analytical Science, The
University of Manchester, PO Box 88, Sackville Street, M60 1QD, UK

ABSTRACT

Current
trends in the demand of middle distillates are stretching the existing hydrogen
production capacity, resulting in a deficit in the refinery hydrogen balance.
Previous approaches in the design of refinery hydrogen networks have neglected
the integration of hydroprocessors in the overall network optimization, which
is critical to bridging the gap between ?white papers? and industrial practice.
As a result, major interactions between process performance and the hydrogen
network are unexploited.

A
method for integrating hydrodesulphurisation process models and multicomponent
hydrogen network model has been developed [1].
However, hydrocracking units and their associated models were not accounted for
in the integrated optimisation of multicomponent hydrogen networks. The present
work describes the integration of hydrocracker process models and multicomponent
hydrogen network models. An overall feed conversion model and a five-lump
experiential yield model has been developed based on the feed characteristics,
catalyst properties and process operating conditions. The model is capable of
predicting conversion and product yields in hydrocracking processes. The proposed
model is validated with different feedstock properties and shows good agreement
with industrial data. Of crucial importance is the integration of the models in
the overall refinery framework to exploit the interactions between process
performance and the hydrogen network. The integrated superstructure consisting
of dynamic interactions between hydrocracking processes and the multicomponent
hydrogen network is optimized with the CONOPT solver in General Algebraic
Modelling System (GAMS).   The effects of feed characteristics and operational
changes on conversion and product yields are investigated. The results
demonstrate expected industrial trends from the effect of changing operating
conditions on product yields. As demonstrated in a case study, by integrating
hydrocracking models into multicomponent hydrogen networks, the motivation for
refinery hydrogen management can now be approached from a realistic and
holistic view to optimising hydrogen use.

Reference

1     
Umana
B, Shoaib A, Zhang N, Smith R. Integrating hydroprocessors in refinery hydrogen
network optimization. Applied Energy. 2014; 133:169-182.