Journal Articles

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Author: search.filters.author.Koh, Kho King.Subject: search.filters.subject.Heat exchanger

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    Design verification of heat exchanger for ballast water treatment
    (Jurnal Teknologi, 2014) Balaji, Rajoo.; Yaakob, Omar.; Adnan, Faizul Amri bin.; Koh, Kho King.
    Using waste heat from ship’s engines is one of the methods considered for heat treatment of ballast water. For such a system harvesting the engine exhaust heat, a heat exchanger will be vital. Design optimisation of a heater employing exhaust gases of the engine as utility fluid and ballast sea water as the process fluid was achieved using Lagrangian methods, keeping the annual cost as the objective function. Costs for installation, maintenance as also costs for the utility and process fluids were considered. Heat balance data, specific fuel consumption values from a typical operational ship and current fuel costs were considered for the design. The thermodynamic and geometric designs were worked out using computer based software for comparing the designs. Costs were also computed using a different approach for all the designs. Since the amount of heat transferred was specified and the application was limited to a single process, direct cost method was used for the computation. The objective function values obtained from Lagrangian equations were compared with the values obtained from direct cost computations. From the optimal designs, choice was justified based on annual cost, optimum exit temperature of shell side fluid and optimum mass flow of tube side fluid.
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    A study of ballast water treatment using engine waste heat
    (Journal of The Institution of Engineers (India): Series C, 2019-04) Balaji, Rajoo.; Yaakob, Omar.; Koh, Kho King.; Adnan, Faizul Amri bin.; Ismail, Nasrudin bin.; Ahmad, Badruzzaman bin.; Ismail, Mohd Arif bin.
    Heat treatment of ballast water using engine waste heat can be an advantageous option complementing any proven technology. A treatment system was envisaged based on the ballast system of an existing, operational crude carrier. It was found that the available waste heat could raise the temperatures by 25 C and voyage time requirements were found to be considerable between 7 and 12 days to heat the high volumes of ballast water. Further, a heat recovery of 14–33% of input energies from exhaust gases was recorded while using a test rig arrangement representing a shipboard arrangement. With laboratory level tests at temperature ranges of around 55–75 C, almost complete species mortalities for representative phytoplankton, zooplankton and bacteria were observed while the time for exposure varied from 15 to 60 s. Based on the heat availability analyses for harvesting heat from the engine exhaust gases(vessel and test rig), heat exchanger designs were developed and optimized using Lagrangian method applying Bell–Delaware approaches. Heat exchanger designs were developed to suit test rig engines also. Based on these designs, heat exchanger and other equipment were procured and erected. The species’ mortalities were tested in this mini-scale arrangement resembling the shipboard arrangement. The mortalities realized were[95% with heat from jacket fresh water and exhaust gases alone. The viability of the system was thus validated.