Abstract—Improved condition monitoring of production equipment enhances process safety and the ability to perform preventive maintenance, thus reduces downtime and associated costs. Condition monitoring or early detection is an integrated part of Abnormal Situation Management (ASM) and is becoming more and more important to chemical process industries due to safety, environmental, and economic reasons. Despite these developments, ASM is generally poorly practiced in the process industries. Much of the actual practice places the onus on plant operators to respond effectively to abnormal conditions. The objective of this article is to plot the data in real time for the detection of fouling in air-cooled exchangers and leaks due to longitudinal bypass in shell and tube heat exchangers. This data is obtained from the Distributive Control System (DCS) historian in the case of shell and tube heat exchanger and experimental methods for air cooled heat exchangers respectively. In this research apparent fouling in one of the shell and tube heat exchanger was actually longitudinal baffle bypass leak. The methodology used in this study is non-intrusive condition monitoring of the heat exchangers of a petrochemical plant. For the air cooled heat exchangers, the data is obtained by using a hot wire anemometer to measure the air flow and thermocouple wire to measure the temperature of the air for both inlet and outlet conditions respectively. The data got is then analyzed by using heat transfer equations and ASPEN exchanger design program. In the case of shell and tube heat exchangers the flow rate and temperature data of both the shell side and tube side fluid is got from the DCS historian respectively. Then using the heat transfer equations for a shell and tube heat exchanger the data is plotted and analyzed. The results obtained indicate that fouling in the case of air cooled heat exchangers takes place on the air side and is higher in carbon steel tubes than in admiralty. In the case of shell and tube heat exchangers for the BFU type; apparent fouling is actually the longitudinal bypass leak which is severe. For the BEU type fouling, it is due to gum formation and is verified from the data. The schemes for early detection of the above are expected to be a useful for the development of a diagnostic tool for operation alert for ASM and preventive maintenance respectively.
Index Terms—Abnormal situation management, fouling, longitudinal baffle leak, heat transfer.
William P. Swan was with SASOL, Lake Charles, Louisiana, USA (email: bswanfamily@aol.com).
Dan P. Fernandes, is with the Center for Abnormal Situation Management Research, Lamar University, Beaumont, Texas 77710, USA (email:dfernandes@lamar.edu).
Aniket Khade and Daniel H. Chen are with the Center for Abnormal Situation Management Research, Lamar University, Beaumont, Texas 77710, USA (email: akhade@lamar.edu, Daniel.chen@lamar.edu).
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Cite: William P. Swan, Dan P. Fernandes, Aniket Khade, and Daniel H. Chen, "Abnormal Situation Management: Detection of Fouling and Longitudinal Bypass in Heat Exchangers," International Journal of Chemical Engineering and Applications vol. 9, no. 1, pp. 9-15, 2018.
