MSF PERFORMANCE IMPROVEMENT BY USING THERMO-VAPOR COMPRESSION. Masters thesis, King Fahd University of Petroleum and Minerals.

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Arabic Abstract

من خلال هذه الدراسة تم عمل تحليل لنظام تحلية التقطير الوميضي والذي يعد أهم تقنية لتحلية مياه البحر. الهدف من هذا البحث هو رفع كفاءة النظام وذلك باستخدام الضاغط الحراري الذي يعمل على ضغط جزء من البخار المنتج في وحدة التحلية ويتم خلطها مع بخار متوسط الضغط قادم من الغلاية حيث أن البخار الناتج من هذا الضاغط يتم توجيه الى مسخن المحلول الملحي بهدف رفع درجة الحرارة لمياه البحر قبل ادخالها الى حجرة التبخير. باعتبار ذلك كشفت الدراسة بعد اجراء التحليل الشامل ان أفضل موضع للضاغط الحراري هو عند المرحلة رقم 8 حيث أن مواصفات تشغيل المسخن تكون مستوفية وقابلة للتطبيق. على الجانب الاخر معامل الاداء سيرتفع بنسبة 51 % حيث أن البخار المستخدم من الغلاية سينخفض بنسبة 33 % مما يعزز من كفاءة النظام حراريا. من المهم ان نذكر ايضا من خلال نتائج هذه الدراسة ان استبدال تغذية نظام التحلية من بخار .% ذات ضغط منخفض الى بخار ذو ضغط متوسط سوف ينعكس ايجابا على حفظ الطاقة بنسبة 15 أخيرًا، تلقي هذه الدراسة الضوء على طريقة تغذية بالبخار من محطة توليد الكهرباء عند 1.2 بار و 108 درجة مئوية والتي لم تحظ باهتمام الباحثين في تحليل الطاقة المهدرة وإمكانية تعويضها بنظام أخر أكثر كفاءة.

English Abstract

Multi-Stage Flashing, MSF is still a dominant thermal desalination technology in comparison with other desalination technologies in spite of the recent, rapid development of multi effect distillation in terms of bulk production and performance ratio. However, Gulf countries are paying millions to develop system performance and production by implementing new ideas or coming up with merging concepts between thermal desalination technologies such as integrating MSF with thermo-vapor compression and studying how the potential improvement as well as best performance ratio that can be optimized. In this work, we focus on MSF multi-stage flash with thermo-vapor compressor and analyze positioning the TVC in different locations to find out the most suitable stage for TVC connection, which can result in the best performance ratio and production rate. The proposed MSF-TVC system has significantly higher thermal performance ratio than conventional MSF, which implies reduction in input energy to the system per unit mass of product water as well as the reduction of heat transfer area. EES (Engineering Equation Solver) software is used for performing the mathematical analysis of the system. The code is validated through comparison with actual operating data of an existing plant. Therefore, real data for Al-Juabil plant phase-2 has been used and system detailed analysis is regenerated. Results showed very good accuracy for the important process variables in comparison with the Al-Jubail plant. We integrated many configurations of TVC, either single or double stage TVCs with MSF system. The analysis has been carried out on the same unit production of 1245 m3/h by normalizing other process variables such as steam flow rate and brine recycle for the MSFTVC system. A significant improvement of PR found from 8.58 to 12.96 is shown. It’s also important to state that the entrained vapor by TVC from one selected stage would result in a penalty of reduction of recovered heat to the circulating brine before it is introduced to brine heater leading to a temperature drop by one stage (ΔT). Accordingly, the capital cost might drop since the condenser tubes that are either totally or partially removed in order to control the amount of entrained vapor to the TVC. Moreover, the comparison between the original system and the MSF-TVC system has shown a significant drop of about 34% of cooling seawater. Nevertheless, the study reveals that MSF-TVC system has shown significant impact toward power plant where utilizing the medium pressure steam instead of low pressure steam leading to 15 % energy saving due to reduction in thermal energy losses. Finally, this study sheds light on the possibility to have steam feed from power plant at 1.2 bar and 108 °C that has not received enough attention by researchers.

Item Type: Thesis (Masters)
Subjects: Engineering
Department: College of Engineering and Physics > Mechanical Engineering
Committee Advisor: Antar, Mohammed
Committee Members: Antar, Mohammed and Zubair, Syed and Hamad, Osman
Depositing User: MUSA ASSERI (g201410580)
Date Deposited: 15 Oct 2019 08:47
Last Modified: 01 Nov 2019 18:01