• Energy Research

Resistance parameters are essential for the prediction of pressure drop in bag filters. The reported values for limestone dust differ in magnitude and also depend on operating parameters. In this work, experimental data is provided from a pilot scale pulse-jet regenerated bag filter test facility for three types of needle felts using air and limestone dust at ambient conditions. Results reveal that specific resistance of filter media is independent of velocity while the specific resistance of filter cake increases linearly with filtration velocity. Residual pressure drop is almost constant, independent of upper pressure drop limit. The cake resistance at constant velocity fits to a second degree polynomial whereas it increases linearly with the velocity. A linear relation is reported here for all the cases. The resistance of filter cake decreases at higher upper pressure drop limit.

La récupération du pétrole améliorée par le CO2 en utilisant un tensioactif philique de CO2 nouvellement synthétisé comme agent de contrôle de la mobilité du CO2 est rapportée. Le sulfonate d'éthoxylate de nonyl phénol (NPE) a été préparé par estérification de l'alcool avec de l'anhydride maléique suivie de sa sulfonation. L'effet de la tension interfaciale (IFT) entre le CO2 et la saumure à l'aide de NPE a été étudié pour vérifier la philicité du CO2 du tensioactif. Le compte rendu détaillé des effets de la pression et de la température sur l'IFT entre le CO2/saumure en présence et en l'absence de tensioactif sur les conditions de pression et de température spécifiées est étudié et discuté. LES NPE ont effectivement abaissé l'IFT entre le CO2/saumure (30 mN/m) à moins de 5,23 mN/m. La quantité de mousse a été améliorée en utilisant la bétaïne comme booster de mousse. Les propriétés d'endurance de la mousse statique en présence et en l'absence d'huile ont également été examinées avant le test de performance réel des tensioactifs à l'aide d'un échantillon de bouchon de réservoir. Il a été noté que la stabilité de la mousse était de 900 s en présence d'huile à 90 °C dans un environnement de CO2. L'effet de la mousse en utilisant DES NPE synthétisés sur la mobilité du CO2 est également présenté. Le facteur de réduction de la mobilité du CO2 s'est avéré être de 3,1. Il est conclu que LES NPE ont un grand potentiel pour les applications CO2-EOR. Se informa de la recuperación de petróleo mejorada con CO2 mediante el uso de un tensioactivo fílico de CO2 recién sintetizado como agente de control de la movilidad de CO2. El nonil fenol etoxilato sulfonato (NPES) se preparó mediante la esterificación de alcohol con anhídrido maleico seguido de su sulfonación. Se investigó el efecto de la tensión interfacial (IFT) entre el CO2 y la salmuera utilizando NPE para verificar la filicidad del CO2 del tensioactivo. Se estudia y discute la explicación detallada de los efectos de la presión y la temperatura en el IFT entre CO2/salmuera en presencia y ausencia de tensioactivo en condiciones específicas de presión y temperatura. LOS NPE redujeron efectivamente el IFT entre CO2/salmuera (30 mN/m) a menos de 5,23 mN/m. La cantidad de espuma se mejoró mediante el uso de betaína como refuerzo de espuma. Las propiedades estáticas de resistencia de la espuma en presencia y ausencia de aceite también se examinaron antes de la prueba de rendimiento real de los tensioactivos utilizando una muestra de tapón de núcleo de depósito. Se observó que la estabilidad de la espuma era de 900 s en presencia de aceite a 90 °C en un entorno de CO2. También se presenta el efecto de la espuma mediante el uso de NPE sintetizados sobre la movilidad del CO2. Se encontró que el factor de reducción de la movilidad de CO2 era de 3,1. Se concluye que los NPE tienen un gran potencial para aplicaciones de CO2-EOR. CO2 enhanced oil recovery by using newly synthesized CO2 philic surfactant as CO2 mobility control agent is reported. Nonyl phenol ethoxylate sulphonate (NPES) was prepared by the esterification of alcohol with maleic anhydride followed by its sulphonation. Effect of interfacial tension (IFT) between CO2 and brine using NPES was investigated to verify the CO2 philicity of the surfactant. The detailed account of effects of pressure and temperature on IFT between CO2/brine in the presence and absence of surfactant on specified pressure and temperature conditions is studied and discussed. NPES effectively lowered the IFT between CO2/brine (30 mN/m) to less than 5.23 mN/m. Foam quantity was improved by using betaine as foam booster. The static foam endurance properties in the presence and absence of oil were also examined prior to the actual performance test of surfactants using a reservoir core plug sample. It was noted that the foam stability was 900 s in the presence of oil at 90 °C in CO2 environment. The effect of foam by using synthesized NPES on mobility of CO2 is also presented. The CO2 mobility reduction factor was found to be 3.1. It is concluded that NPES has great potential for CO2-EOR applications. تم الإبلاغ عن استخلاص النفط المحسن لثاني أكسيد الكربون باستخدام خافض التوتر السطحي لثاني أكسيد الكربون المركب حديثًا كعامل تحكم في حركة ثاني أكسيد الكربون. تم تحضير نونيل فينول إيثوكسيلات سلفونات (NPES) عن طريق استرة الكحول باستخدام أنهيدريد الماليك متبوعًا بكبريتاته. تم التحقيق في تأثير التوتر البيني (IFT) بين ثاني أكسيد الكربون والمحلول الملحي باستخدام NPES للتحقق من صحة ثاني أكسيد الكربون للمادة الخافضة للتوتر السطحي. تتم دراسة ومناقشة الحساب التفصيلي لتأثيرات الضغط ودرجة الحرارة على IFT بين ثاني أكسيد الكربون/المحلول الملحي في وجود وغياب المادة الخافضة للتوتر السطحي على ظروف الضغط ودرجة الحرارة المحددة. خفضت NPES بشكل فعال IFT بين CO2/محلول ملحي (30 مللي نيوتن/م) إلى أقل من 5.23 مللي نيوتن/م. تم تحسين كمية الرغوة باستخدام البيتين كمعزز للرغوة. كما تم فحص خصائص تحمل الرغوة الساكنة في وجود الزيت وغيابه قبل اختبار الأداء الفعلي للمواد الخافضة للتوتر السطحي باستخدام عينة سدادة الخزان الأساسية. لوحظ أن استقرار الرغوة كان 900 ثانية في وجود الزيت عند 90 درجة مئوية في بيئة ثاني أكسيد الكربون. كما يتم عرض تأثير الرغوة باستخدام NPES المركبة على حركة ثاني أكسيد الكربون. تم العثور على عامل تقليل حركة ثاني أكسيد الكربون ليكون 3.1. تم التوصل إلى أن NPES لديها إمكانات كبيرة لتطبيقات CO2 - EOR.

AbstractThe axial velocity in two different tests with pulse‐jet bag filters made of needle felts on a pilot‐scale test facility separating limestone dust from air under ambient conditions is measured and simulated at different cake area loads. Results reveal that the axial velocity profiles are not truly linear along the whole length of the bag. A nonuniform gas flow prevails when the bags are differently dust‐loaded. The same behaviors are observed even at the end of filtration cycles at different upper pressure drop limits. At the higher upper limit, the nonuniformity is stronger. Radial velocity profiles are nearly symmetric along the length of the bag.

AbstractCoal–water slurry (CWS) has been targeted as a promising fuel and an alternative to fuel oil. CWS has numerous advantages of low and convenient transportation and high solid content. Pakistan is going through a severe energy crisis and among the top 10 countries facing energy crises reported by the United Nations. Besides, Pakistan has become the top seventh country in coal reserves (i.e., 185 billion tones) after the discovery of huge lignite coal reserves in Thar, Sind province. Previous studies investigated the use of additives to enhance CWS properties at a low shear rate and its utilization accordingly. Particularly, the present work studied the high range of shear rate to improve the properties of CWS for transportation and combustion purposes. This study on the improvement in performance of rheology properties of CWS is conducted to improve the properties by cost‐effective additives. The coal concentration varies from 20% to 60%, whereas runs were carried out with and without the cost‐effective additives. The results demonstrated that the coal slurry showed shear‐thinning property when viscosity was increased at high concentrations in the absence of additives. The addition of additive changed the rheological behavior from pseudoplastic to dilatant region. The presence of a high fraction of coal increased the apparent viscosity of CWS. The static stability test of all coal samples was performed using rod drop method at concentrations of 40% to 60%. The study found that stability was achieved earlier with a lower concentration of 40% as compared with higher concentrations of 50–60%. It is expected that this research would be helpful for the country facing adverse energy crises that badly affect the economy and other social aspects of human life.

Abstract Energy/Power is an important element of social and economic development. Without availability of energy at a reasonable price, there is little prospect of developing the country's economy and people's living conditions. A quarter of Pakistani population have no access to electricity, and currently a shortage of 5.0–7.0 GW power supply causes load shedding/blackout problems. In Pakistan, most of the power is generated from non-renewable sources like natural gas etc. Pakistan receives almost 15.525 × 1014 kW-hour of solar energy per year and sunshine duration is normally 8.0–10.0 h per day. Animal/farm wastes are readily available in Pakistan. Residues from these sources produce 103.0 billion m3 of biogas per year that is equivalent to 63.20 TWh. The objective of this study is energy production by using easily available indigenous resources. In this study a 3.0 kW integrated solar/biogas power generation system consist of 2.84 kW solar system and 4.0 m3 biogas system is designed and installed. This paper also present simulation model of system. A hybrid inverter is used to convert DC power of photovoltaic modules and the battery bank in to AC power and combines with the output power of biogas generator. Performance of the hybrid system are analysed from May 1, 2018 to June 15, 2018. During the test maximum power produce by the integrated system is 1.10 kW in morning, 2.14 kW in noon and 1.16 kW in afternoon.

Abstract Solar thermal systems are an efficient utilization of solar energy for hot water and space heating at domestic level. A Solar Water Heater (SWH) incorporating an Evacuated Glass Tube Collector (EGTC) is simulated using TRNSYS software. Efficiency parameters are pointed, and a parametric optimization method is adopted to design the system with maximum conceivable efficiency. In the first part, the selection of refrigerant for heat transportation in SWH loop is presented. A set of 15 working fluids are chosen, and their chemical properties are computed using NIST standard software (REFPROP). The selected working fluids are tested in the system under study and plots for energy gain and temperature are plotted using TRNSYS. Results showed that ammonia (NH3) having specific heat 4.6kJ/kg-K and fluid thermal conductivity 2.12 kJ/hr-m supplies peak energy gain of 7500 kJ/h in winter and 8900 kJ/h in summer season along 120 °C temperature rise. On the other hand, R-123 having specific heat 0.65kJ/kg-K and fluid thermal conductivity 0.0293kJ/hr-m showed inferior performance during the simulation. A solar-hydrogen co-generation system is also designed and simulated under low solar insolation and warm climate regions to study annual hydrogen produced by the hybrid system. System comprises main components: a PV array, an electrolyzer, a fuel cell, a battery, a hydrogen storage unit and a controller in the complete loop. Results of Hydrogen cogeneration system provide 7.8% efficiency in the cold climate of Fargo North Dakota state due to lower solar insolation. While hot climate condition of Lahore weather provides efficiency of 11.8% which satisfy the statistics found in literature.

Pulse-jet bag filters are frequently employed for particle removal from off gases. Separated solids form a layer on the permeable filter media called filter cake. The cake is responsible for increasing pressure drop. Therefore, the cake has to be detached at a predefined upper pressure drop limit or at predefined time intervals. Thus the process is intrinsically semi-continuous. The cake formation and cake detachment are interdependent and may influence the performance of the filter. Therefore, understanding formation and detachment of filter cake is important. In this regard, the filter media is the key component in the system. Needle felts are the most commonly used media in bag filters. Cake formation studies with heat treated and membrane coated needle felts in pilot scale pulse jet bag filter were carried out. The data is processed according to the procedures that were published already [Powder Technology, Volume 173, Issue 2, 19 April 2007, Pages 93-106]. Pressure drop evolution, cake height distribution evolution, cake patches area distribution and their characterization using fractal analysis on different needle felts are presented here. It is observed that concavity of pressure drop curve for membrane coated needle felt is principally caused by presence of inhomogeneous cake area load whereas it is inherent for heat treated media. Presence of residual cake enhances the concavity of pressure drop at the start of filtration cycle. Patchy cleaning is observed only when jet pulse pressure is too low and unable to provide the necessary force to detach the cake. The border line is very sharp. Based on experiments with limestone dust and three types of needle felts, for the jet pulse pressure above 4 bar and filtration velocity below 50 mm/s, cake is detached completely except a thin residual layer (100-200 μm). Uniformity and smoothness of residual cake depends on the surface characteristics of the filter media. Cake height distribution of residual cake and newly formed cake during filtration prevails. The patch size analysis and fractal analysis reveal that residual cake grow in size (latterly) following regeneration initially on the base with edges smearing out, however, the cake heights are not leveled off. Fractal dimension of cake patches boundary falls in the range of 1-1.4 and depends on vertical position as well as time of filtration. Cake height measurements with Polyimide (PI) needle felts were hampered on account of its photosensitive nature.