البحث — المستودع الرقمي العراقي

المستخلص: مياه الصرف الصناعي لمصافي النفط الناتجة بصورة رئيسية من عمليات تكرير النفط الخام والصناعات التحويلية، مواد التشحيم والبتروكيماويات الوسيطة. هذه السوائل هي المصدر الرئيسي للتلوث البيئي المائي. تتكون مياه الصرف الصناعي من الزيوت والشحوم والمركبات العضوية ا | Petroleum refinery wastewater originating from petroleum industries primarily resulted in refining crude oil and manufacturing fuels, lubricants and petrochemical intermediates. These effluents are a major source of aquatic environmental pollution. The wastewaters are composed of oil and grease, toxic organic compounds along with many other minerals. In this study, wastewater of Al - Najaf petroleum refinery was used as electrolyte solution in the experiments, and the effect of some variables on the removal of organic material as a pollutant in term of COD were studied. The performance of anodic oxidation represented by COD removal was studied using 1 liter batch - mode parallel plate electrochemical reactor at constant initial COD concentration and fixed agitation speed of 250 rpm with the variation of operating conditions that were expected to have a major effect on process. These variables were : electrodes material (platinum, stainless steel, graphite, PbO2, and carbon felt), current densities (5, 15, 25) mA cm - 2 for carbon felt electrode and (10, 30, 50) mAcm - 2 for other electrodes, pH (4, 7, 10), temperatures (25, 40, and 55)?C and with electrolysis time up to 120 minutes. The results show that the direct anodic oxidation process gave the best COD removal percent of 84.88% and 86.27% at 50 and 25 mA cm - 2 current densities for PbO2 and carbon felt anode materials, respectively. The highest COD removal was predicted at pH 4 and the best temperature at 55?C for all electrode types. The reaction was followed by pseudo first - order kinetics rate. As well, it was studied the effect of current density on the current efficiency, instantaneous current efficiency, energy consumption, charge load with the time and calculated activation energy.

تحسين الاداء الحراري للمائع النانوي في المبادلات الحرارية == Enhancement Of Thermal Performance Of Nanofluids In Heat Exchangers

اسم المؤلف: شهد فالح حسن

اسم المشرف: تحسين علي الحطاب

الموضوع العام: الهندسة الكيمياوية

السنة: 2017

الموضوع الدقيق: الهندسة الكهروكيمياوية

الدرجة: ماجستير

الجامعة: جامعة بابل - كلية الهندسة - قسم الهندسة الكيمياوية

اللغة: الانكليزية

مكان الجامعة: بابل

الصفحات الاولى:

المستخلص: التقنية الواعدة التي تستخدم لتعزيز عملية الانتقال الحراري هي باستخدام الموائع النانوية كخيار جيد واستبدالها محل السوائل التقليدية الشائعة. والمبادلات الحرارية هي معدات واسعة التطبيق في كثير من التطبيقات الصناعية المختلفة وبالتالي يكون سلوك وخصائص المائع | The most promising technique that is used to enhance the thermal performance for the heat transfer processes is using the nanofluids as a good choice to replace the conventional fluids. The heat exchangers are the wide range application equipment that is used for different industrial applications and therefore, the properties and the behavior of the fluid media are the main control parameters in equipment design of the heat exchangers. In this work an attempt was made to investigate experimentally the thermal performance of nanofluid which consists of deionized water (DI) as a base fluid and Aluminum oxide (Al2O3) as solid nanoparticles. The investigation includes two parts, the first one is studying the effect of addition of solid nanoparticles to the base fluid on the thermo - physical properties such as density, viscosity and thermal conductivity for different values of the volume fraction of nanoparticles. The second part includes the experimental work studying the effect of the nanoparticles (Al2O3) volume fraction (0.05, 0.1 with base fluid ), heat flux (With three values 7.4W,11W,16.8W) and angle (With two values 90?,45?) with four models (four different type from wicks in heat pipe) to enhance the heat transfer in heat pipe with two cases of transient temperature distribution and steady state. One model is different from the other by using different wicks in a heat pipe in all models. The general results referred to the enhancement of heat transfer rate are represented by increasing the concentration of nanoparticles (Al2O3) volume fraction such as (?=0.1) is better than (?=0, ?=0.05), increasing heat flux such as (16.8W) is better than (7.4W,11W) and an inclination angle such as( 45?) is better than (90?).At the transient state the time to reach to the steady state decreases when the concentration of the nanoparticles (Al2O3) volume fraction increases, the heat flux increases and the angle incline. In model 4 the heat transfer enhancement is better than that of model 3 and model 3 is better than that of model 2 and model 2 is better than that of model 1.The time to reach the steady state decreases in model 4 more than model 3, model 2 and model 1. The temperature decreases in the heat pipe when we gradually sidle from heater. The time to reach to steady state found in model 4 at concentration of nanofluid (?=0.1) and heat flux (16.8W) in angle (45?) is (19 min). In the steady state when we increase the concentration of the nanoparticles (Al2O3) volume fraction at the same distance (z) the temperature increases ,The increase in the heat flux of the hot part of the heat pipe will always increase the temperature in the heat pipe and the temperatures distribution in the heat pipe will be improved. The thermal performance of the heat pipe is enhanced by increasing the concentration of the nanofluid , the heat flux and by inclining the heat pipe from 90? angle to 45? angle such as in result of model 4.