Master Dissertations

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Author: search.filters.author.Eswara, Arun KishoreHas files: Yes

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    Design of plate fin heat exchanger with offset strip fins for the liquefaction of natural gases
    (Indian Maritime University, Kolkata Campus, 2019-06-20) Kashiwal, Mukul; Eswara, Arun Kishore
    In the cryogenic systems such as liquefier, cryo-coolers, etc. the heat exchangers are one of the most critical components. The heat exchanger used in cryogenic applications must have high effectiveness to produce a proper refrigerating effect and it should not be less than 85%. It has already experimented that if the value of the effectiveness of the heat exchangers falls below the design value, then the no liquid will be produced. On a general basis, there are so many heat exchangers available in the industry which are used in the cryogenic works but there is a special category of the heat exchangers that are available, which are now used widely because of there because of their compactness, low weight, and high effectiveness. These heat exchangers are known as the compact heat exchangers. The objective of this work is to design a plate fin heat exchanger, which is when used in the liquefaction cycle must be able to liquefy the natural gases and to produce 1000 Kg liquid ih a day, which can be transported easily for the various purposes through various ways. This work has been carried on the plate fin heat exchanger with selecting the offset strip fin, which is the most reliable fin design in the liquefaction applications. The work includes the two cryogenic fluids, one is methane and the other is propane. Propane is used as the coolant to bring down the temperature of methane to this close that when passed through the expander or by precooling in the liquefaction cycle it gets liquefied easily. Catia software was used to model the component and Matlab programming has also been done to design a plate fin heat exchanger. As the geometry were too complex to analyse in the software because of the physical memory limitation, a small symmetric part of the heat exchanger model were imported in the analysis software called Ansys 18.1 for the validation of the results and it can be concluded from the observations that the model is capable to do the desired function. A small variation in the calculation and analysis results has been observed, and the effectiveness of the heat exchanger was found to be above 90 %. Aluminium 3003 has been used as the material for the fins strips and for separating plate.
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    Design of small scale liquefaction cycle for natural gas
    (Indian Maritime University, Kolkata Campus, 2019-06-19) Gupta, Nishit; Eswara, Arun Kishore
    Liquefied natural gas is found to be the most economical mode of transportation for distances covering more than 3500 miles. The boiling point of natural gas is 111 .7 K at atmospheric pressure and falls under the category of cryogenics. The process has components such as compressor, heat exchanger, expansion valve, insulating material, storage tank and pipes. The liquefaction of natural gas is achieved by processing natural gas in the liquefaction cycle. There are many parameters affecting the cycle such as compressor efficiency, heat exchanger effectiveness, ambient temperature, friction losses in pipes and insulating materials. In this thesis, some of the above mentioned parameters are considered while some parameters are neglected or assumed appropriately. It is observed that out of the existing cycles such as simple Linde-Hampson cycle, Pre-cooled cycle, Claude cycle and Kapitza cycle, each cycle has its own benefits and drawbacks. The fraction of liquefaction is found maximum for simple Claude cycle while the work required also reduces due to expansion of the high pressure gas through reciprocating expansion engine. The iterative procedure to find the configuration of each cycle is explained in the thesis and can be used with minimum bare inputs. An experimental setup can be built through these configurations and better study can be performed. To obtain the results, residue in the iterations is taken to 0.1 for temperature, pressure and mass flow rate both. In the Claude cycle, for mass flow rate of 1.02 kg/sec and the pressure ratio of 40, the fraction of liquefaction is found 0.0646 while in the kapitza cycle, for mass flow rate of 1.35kg/sec and the pressure ratio of 40, the fraction of liquefaction is found as 0.040. It is found that, the pressure required to liquefy the gas is not practical in the case of Linde-Hampson cycle. Further, it is found that Claude and Kapitza cycle can be used for experimental purpose.