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Heat exchanger networks have been known to be the essential parts in the chemical industries. Unfortunately, since the performance of heat exchanger can be decreasing in transferring the heat from hot stream into cold stream due to fouling, then cleaning the heat exchanger is needed to restore its initial performance periodically. A process of heating crude oil in a refinery plant was used as a case study. As many as eleven heat exchangers were used to heat crude oil before it was heated by a furnace to the temperature required to the crude unit distillation column. The purpose of this study is to determine the cleaning schedule of heat exchanger on the heat exchanger networks due to the decrease of the overall heat transfer coefficient by various percentage of the design value. A close study on the process of heat exchanger cleaning schedule in heat exchanger networks using the method of decreasing overall heat transfer coefficient as target. The result showed that the higher the fouling value the more often the heat exchanger is cleaned because the overall heat transfer coefficient decreases quickly.

Heat exchanger networks (HENs) play an important role in the chemical industries. Unfortunately, fouling is inevitable in heat exchangers operation. Therefore, the optimal cleaning procedure is required to restore heat exchangers' performance periodically. A systematic cleaning scheduling strategy for the heat exchanger network in an oil refinery is proposed in this work. There are 11 operating heat exchangers in an oil refinery to be reviewed. Different cleaning decision scenarios based on the overall heat transfer coefficient are explored for optimal cleaning schedule performance. The daily number of exchangers available to be cleaned i.e., the unit cleanability, is investigated while minimizing the energy consumption and the additional heat requirement due to the offline heat exchanger under cleaning procedure. The HEN performance and the energy-saving from the cleaning procedures are benchmarked with the uncleaned HEN. The results indicate that the cleaning procedure significantly increases the HEN performance and simultaneously reduces the heat requirement if compared to the untreated HEN benchmark. The possible conflicting situation is discussed when some heat exchangers are waiting to be cleaned due to the unit cleanability restriction, which allows the overall heat transfer coefficient to be below the allowed limit. Therefore, nonconflicting cleaning scheduling is also addressed in this work by relaxing the unit cleanability limit. Furthermore, the optimal cleaning schedule is also suggested for user reference. In this work, the optimum cleaning schedule with minimum energy consumption and maximum energy saving could be achieved when cleaning decision limit is set at 40% decrease of overall heat transfer coefficient. In the contrast, the lowest number of cleaning procedures is associated with 90% decrease in the overall heat transfer coefficient as the cleaning decision limit. [ABSTRACT FROM AUTHOR]

The carbon dioxide emission from the industrial sector and the power plant contribute significantly to global climate change for several decades. The carbon capture and storage technology is the primary solution to reach the reduction target of carbon dioxide emissions. The carbon capture and storage activities involve CO 2 capturing, transporting, and storing in geological storage, requires number planning. The process integration approach by pinch analysis method can be used for the carbon capture and storage planning problem and to develop the carbon capture and storage network design. However, the applicability of the method needs to be evaluated when some constraints in carbon capture and storage network design are applied. This paper proposes an improved pinch analysis based method for carbon capture and storage target and network design. The method begins with targeting the maximum carbon exchange in the carbon capture and storage system, which is followed by designing the carbon capture and storage network. Next, the capital-carbon trade-off is introduced as a new strategy for assessing carbon capture and storage network design to show the economic feasibility of the design. Four case studies demonstrate the applicability of the proposed method to the carbon capture and storage systems in the central and western part of Indonesia. The application of this new strategy in the western part of Indonesia as a single region system revealed that the flat minimum of the total annual cost is obtained at a five year time difference with the amount of up to US$ 149.3 million. Image 1 • A CCS cascade analysis in central and western part of Indonesia was introduced. • A systematic approach in multi-region and multi- period was proposed. • Cascade analysis with minimum time difference was shown to be a good method. • Grid diagram showing the pairing between source and sink was a power tool. • Capital-carbon trade-off as a new strategy was proposed to assess CCS system design. [ABSTRACT FROM AUTHOR]