Evaluation of Heat Exchanger Network Retrofit Design Using Plant Data

Abstract

Fouling in pre-heat trains of atmospheric crude distillation units is one of the major issues hindering the efficiency of oil refineries. This paper illustrates the benefits of using dynamic simulation, combined with plant measurements, to evaluate heat exchanger retrofit opportunities that provide the largest savings to the refinery. Once the fouling behavior of the network is well characterized and the most critical heat exchanger is identified, the performance of a retrofit design for that exchanger is assessed by re-running history using plant measurements for an extended period of operation. The comparison of the original design versus alternative ones, based on the potential reduction of fouling, provides an overall assessment of the impact on energy/economic savings for the whole network given by the proposed retrofits options. This enables the design engineer to use available plant data to evaluate and select the most beneficial design option, not simply based on expected operating conditions and fixed fouling factors, but on time-varying conditions and dynamic fouling build-up as it happens in the plant. The method is demonstrated with an industrial case study. The estimated savings in furnace duty were of 1.5–2.7 MW, resulting in expected economic benefits of $270–700 k per year.

Additional information

Notes on contributors

Emilio Díaz-Bejarano

Emilio Diaz-Bejarano is a senior consultant at Hexxcell Ltd., where he works on the development of Hexxcell Studio^TM and consulting services to oil and gas and process industries. He holds a degree in Chemical Engineering from Universidad de Salamanca, Spain, a M.Sc and a Ph.D. in Chemical Engineering, both from Imperial College London. He was awarded an Iberdrola Foundation Scholarship for Master's Studies in Energy and the Environment and he was recipient of the Geoff Hewitt Prize from Imperial College as the top student in the 2011 M.Sc. His research interests are in process systems engineering and data analytics with focus on the development of mathematical models for heat exchange and energy systems.

Marta Yugo Santos

Marta Yugo Santos is the Concawe Science Executive for Economics and Modeling in the fields of CO₂ and Energy. Her responsibilities include to provide governance and supervision of Concawe’s activities in assessing the economic and GHG emissions impact of emerging technologies, roadmaps and legislation affecting the EU refining sector, the vehicle fleet and the low-carbon economy. She has over 12 years of experience in the Oil and Gas industry initially as a refining process engineer at REPSOL Technology Center and then as a senior Energy and Carbon Analyst in REPSOL’s the Environment and Sustainability division where she took part of the team leading the work presented in this paper before joining Concawe in 2017. She holds a bachelor’s degree in chemical engineering specialized in environment for the Complutense University of Madrid and a M.Sc. degree in Refining, Gas and Marketing.

Manuel García Dopico

Manuel García Dopico is the Heat Transfer Department Manager, in the Engineering Division of Repsol. He has over 23 years of experience in thermal design of shell and tube heat exchanger, aircoolers, fired heaters, boilers, and flares. Prior to Repsol, he has worked in research in “Catalytic Cleaning of flue gas from incinerators”, this research was financed by the European Community in the program "Complete Catalytic Combustion of Halogenated (Waste) Material". He holds a degree in Chemical Engineering from the Complutense University of Madrid and a Ph.D. in Chemical Engineering from the Politecnica University of Madrid.

Francesco Coletti

Francesco Coletti is the Chief Technology Officer of Hexxcell Ltd. where he leads the development of Hexxcell Studio™, an advanced thermo-hydraulic fouling analysis and prediction software, as well as the company’s energy efficiency consulting practice. Prior to Hexxcell, he has worked as a Development Specialist in the Cryogenic Systems R&D group at Praxair Inc. where he focused on mathematical optimization of cryogenic multi-stream heat exchangers and air separation units. He is the Executive Editor of Heat Exchanger Design Handbook and serves as Secretary for the UK National Heat Transfer Committee. He holds a Laurea degree in Chemical Engineering from the University of Padova, Italy, a M.Sc. in Process Systems Engineering and a Ph.D. in Chemical Engineering from Imperial College London.