ARTICLE IN PRESS JID: JTICE [m5G;February 14, 2015;9:59] Journal of the Taiwan Institute of Chemical Engineers 000 (2015) 1–9 Contents lists available at ScienceDirect Journal of the Taiwan Institute of Chemical Engineers journal homepage: www.elsevier.com/locate/jtice A step toward saving energy using thermal modiﬁcation of crude oil preheat network: A case study Arash Shamseddini, Malihe Heravi, Seyyed Mohammad Jokar, Mohammad Reza Rahimpour ∗ Department of Chemical Engineering, School of Chemical and Petroleum Engineering, Shiraz University, Shiraz 71345, Iran article info Article history: Received 6 September 2014 Revised 18 January 2015 Accepted 19 January 2015 Available online xxx Keywords: Heat exchanger network Preheat temperature Thermal modiﬁcation Economic evaluation abstract This paper presents a thermal and economic investigation of a heat exchanger network of a crude distillation unit in its existing conﬁguration, with the aim of increasing the temperature of crude exiting the network and enhances its performance thermally. In the existing system, the crude enters to the preheat network at the temperature of 30 °C and leaves at 188 °C, being heated passing through a combination of nine shell and tube heat exchangers. However, achieving higher temperature is essential due to the extraordinary industrial importance in energy saving. For this purpose, the possibility of higher preheat temperature is investigated, using a computer software analysis, and a new conﬁguration is proposed according to the simulation results. The proposed conﬁguration is also compared with the existing conﬁguration from an economic point of view. Simulation results prove that implementing certain modiﬁcations on the existing design reduces the consumption of utilities and upgrades the performance of the whole process in such a way that a 17 °C rise in temperature of the outgoing crude is achieved. Moreover, a heat recovery boost equal to 4.6 MW is obtained from hot streams using the proposed design. Eventually, the proposed conﬁguration can lead to an improvement of overall process economics. The period of return on investment for the proposed design is about 9 months, proving to be cost effective. © 2015 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers. 1. Introduction Thermal eﬃciency is one of the important factors in industrial plants, especially distillation units and related equipments. The im- provements in thermal energy can be implemented in the processes, components and other effective items providing a reduction in costs and an increase in revenue. 1.1. Crude distillation unit Lots of efforts have been made over the years to analyze crude distillation units (CDU) for energy eﬃciency improvement accord- ing to the estimated amount of the energy required for these unit operations [1]. A crude distillation unit is known as the ﬁrst pro- cess unit of the oil reﬁnery with the purpose of separating the crude oil into fractions with speciﬁed qualities [2]. Various fractions pro- duced by the crude distillation are then introduced to downstream units for additional processing. Crude, as the feed of the distillation unit, should be heated up to a certain temperature before entering the distillation column in which light and heavy fractions are pro- duced from the top and bottom sections, respectively. To provide the ∗ Corresponding author. Tel.: +98 711 2303071; fax: +98 711 6287294. E-mail address: rahimpor@shirazu.ac.ir (M.R. Rahimpour). preheating system, feed/eﬄuent exchangers are usually utilized and this process is completed in heaters. A low preheat temperature is considered as a bottleneck in a typical CDU and clearly the resolution of this issue results in lower fuel consumption in downstream heaters. Accordingly, increasing the crude preheat temperature reduces the duty of the heaters and leads to substantial savings in energy and cost. This temperature increment is dependent not only on changing exchanger’s network conﬁguration, but also on distillation system de- sign, crude hydraulics and heater operation [3]. However, it is worth mentioning that low heat recovery in heat exchanger trains can cause operational problems such as product losses, reduced throughput, ex- cessive loading of the crude distillation column and feed heater and more [4]. Therefore, heat exchanger network (HEN) design has be- come an active research issue in recent decades [5] 1.2. Methodology Increasing demand for energy conservation in the petroleum industry and the growing cost of energy in recent years, a trend likely to remain unchanging in future, has motivated Process Engi- neers to look for optimization techniques and heat-exchanger net- work retroﬁtting, which is deﬁned as modiﬁcation and development in a new conﬁguration of a network in order to optimize existing plant components. The strategies for improving the performance of utilities are far more appealing in reﬁneries where huge amount of http://dx.doi.org/10.1016/j.jtice.2015.01.021 1876-1070/© 2015 Published by Elsevier B.V. on behalf of Taiwan Institute of Chemical Engineers. Please cite this article as: A. Shamseddini et al., A step toward saving energy using thermal modiﬁcation of crude oil preheat network: A case study, Journal of the Taiwan Institute of Chemical Engineers (2015), http://dx.doi.org/10.1016/j.jtice.2015.01.021