Process system engineering in biodiesel production: a review

Biodiesel is fast becoming a popular alternative to fossil fuels, as it is natural, renewable and has low toxic emissions. Strategies that have been adopted to ensure continued growth of the biodiesel industry are policy development, reduction of biodiesel tax, offset funding for incremental fuel cost from CO2 emission fuel and support for research and development of potential biodiesel feedstocks. Recent innovations of biodiesel processes are focused on the development of more efficient catalysts and in the utilization of novel reaction media such as supercritical fluids as well as on a variety of oil feedstocks such as virgin and waste oils. Biodiesel production involves complex processes which require systematic process design and optimization. The main aim of designing biodiesel plants is to maxime conversion of ethyl or methyl esters at the lowest capital cost of the plant. The design should also consider safety and environmental concerns. Process system engineering (PSE) is a systematic approach to design and analyze complex processes by using a variety of PSE tools for the optimization of biodiesel production. This paper reviews the latest PSE tools used in development of novel biodiesel processes. It describes the main PSE elements such as process model development and product design, simulation of biodiesel processes, optimization of biodiesel synthesis, and integration of reactor and separation systems. This review also highlights the sustainability of biodiesel production

Process system engineering in biodiesel production: a review

Biodiesel is fast becoming a popular alternative to fossil fuels, as it is natural, renewable and has low toxic emissions. Strategies that have been adopted to ensure continued growth of the biodiesel industry are policy development, reduction of biodiesel tax, offset funding for incremental fuel cost from CO2 emission fuel and support for research and development of potential biodiesel feedstocks. Recent innovations of biodiesel processes are focused on the development of more efficient catalysts and in the utilization of novel reaction media such as supercritical fluids as well as on a variety of oil feedstocks such as virgin and waste oils. Biodiesel production involves complex processes which require systematic process design and optimization. The main aim of designing biodiesel plants is to maxime conversion of ethyl or methyl esters at the lowest capital cost of the plant. The design should also consider safety and environmental concerns. Process system engineering (PSE) is a systematic approach to design and analyze complex processes by using a variety of PSE tools for the optimization of biodiesel production. This paper reviews the latest PSE tools used in development of novel biodiesel processes. It describes the main PSE elements such as process model development and product design, simulation of biodiesel processes, optimization of biodiesel synthesis, and integration of reactor and separation systems. This review also highlights the sustainability of biodiesel production

Equine sarcoids: Bovine Papillomavirus type 1 transformed fibroblasts are sensitive to cisplatin and UVB induced apoptosis and show aberrant expression of p53

Bovine papillomavirus type 1 infects not only cattle but also equids and is a causative factor in the pathogenesis of commonly occurring equine sarcoid tumours. Whilst treatment of sarcoids is notoriously difficult, cisplatin has been shown to be one of the most effective treatment strategies for sarcoids. In this study we show that in equine fibroblasts, BPV-1 sensitises cells to cisplatin-induced and UVB-induced apoptosis, a known cofactor for papillomavirus associated disease, however BPV-1 transformed fibroblasts show increased clonogenic survival, which may potentially limit the therapeutic effects of repeated cisplatin treatment. Furthermore we show that BPV-1 increases p53 expression in sarcoid cell lines and p53 expression can be either nuclear or cytoplasmic. The mechanism and clinical significance of increase/abnormal p53 expression remains to be established

Methyl esters selectivity of transesterification reaction with homogenous alkaline catalyst to produce biodiesel in batch, plug flow, and continuous stirred tank reactors

Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case 1 and Case 2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60 C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations

Methyl esters selectivity of transesterification reaction with homogenous alkaline catalyst to produce biodiesel in batch, plug flow, and continuous stirred tank reactors

Selectivity concept is essential in establishing the best operating conditions for attaining maximum production of the desired product. For complex reaction such as biodiesel fuel synthesis, kinetic studies of transesterification reaction have revealed the mechanism of the reaction and rate constants. The objectives of this research are to develop the kinetic parameters for determination of methyl esters and glycerol selectivity, evaluate the significance of the reverse reaction in transesterification reaction, and examine the influence of reaction characteristics (reaction temperature, methanol to oil molar ratio, and the amount of catalyst) on selectivity. For this study, published reaction rate constants of transesterification reaction were used to develop mathematical expressions for selectivities. In order to examine the base case and reversible transesterification, two calculation schemes (Case 1 and Case 2) were established. An enhanced selectivity was found in the base case of transesterification reaction. The selectivity was greatly improved at optimum reaction temperature (60 C), molar ratio (9 : 1), catalyst concentration (1.5 wt.%), and low free fatty acid feedstock. Further research might explore the application of selectivity for specifying reactor configurations

Microbial dynamics during various activities in residential areas of Lahore, Pakistan

Bioaerosols are ubiquitous in the atmosphere with their levels affected by a variety of environmental factors as well as type of activities being carried out at any specific time. The present study investigated how indoor activities influence bioaerosol concentrations in five residential houses of Lahore. Agar coated petri plates were exposed face upwards for twenty minutes in kitchens and living rooms during activity and non-activity periods. The temperature and relative humidity levels were noted as well. The bioaerosol concentrations in kitchens during the activity time ranged between 1022 to 4481 cfu/m3 and in living rooms from 1179 to 3183 cfu/m3 . Lower values were observed during non-activity periods. A paired-t test revealed a significant difference in bacterial loads during activity and non-activity times in both micro-environments (p = 0.038 in kitchen and p = 0.021 in living room). The predominant species identified were Micrococcus spp., Staphylococcus spp., and Bacillus spp. which are a common constituent of the indoor environment and are known to be opportunistic pathogens as well

Measurement of NO2 indoor and outdoor concentrations in selected public schools of Lahore using passive sampler

Higher levels of NO2 are a danger to human health especially for children. A seven day study was carried to find out the ambient concentrations of NO2in 27 schools of Lahore with the help of passive samplers. In each school three sites were selected, viz: laboratory, corridor and outdoors. After 7 days exposure the tubes were subjected to spectrophotometric analysis. Results showed that the maximum values measured in laboratory, outdoor and corridors were 376µg/m3 , 222µg/m3 and 77µg/m3 . Minimum values for laboratory, outdoor and corridors were 10µg/m3 , 20µg/m3 and 8µg/m3 . Factors affecting these values were laboratory activities and proximity to main roads. These values were significantly higher than the standard values defined by EPA. Therefore children in schools were at risk of developing health complications

Study on low-grade galena-barite ore beneficiation in Khuzdar, Balochistan, Pakistan

Purpose. Galena and barite are the principal minerals of lead and barium respectively. Both minerals are used extensively in industries because of their distinct properties. In complex poly metallic ores, it is always desirable to produce separate mineral concentrates for subsequent metal extraction. Separation of two or more minerals from complex low-grade multi-metallic ore into commercial grade concentrates requires suitable process. Methods. This research work is centered on development a suitable process for the beneficiation of a low-grade galena-barite ore originating from Khuzdar region (Balochistan Province, Pakistan). Findings. The low-grade ore assaying 39.90% Pb and 24.64% BaSO4 was beneficiated on bench-scale by sequential froth flotation process to recover valuable galena and barite concentrates. The important variables of froth flotation process such as feed size, pulp pH, pulp density, impeller speed, type and quantities of flotation reagents, pulp conditioning time and froth collecting time were optimized to achieve maximum recovery and grade of both concentrates. The rougher galena and barite concentrates were re-ground separately and subjected to one cleaning flotation to obtain better grade final concentrates of respective minerals. Originality. A process flow-sheet was designed in the light of this study. Practical implications. Froth flotation experiments showed that a galena concentrate containing 77.38% Pb with recovery of 90.64% and a barite concentrate assaying 90.23% BaSO4 with recovery of 80.16% could be recovered from this ore. Both the concentrates fall in the category of metallurgical and chemical grades and are suitable for industrial applications.Мета. Підвищення якості низькосортної галеніт-баритової руди, знайденої в Хуздарском районі провінції Белуджистан (Пакистан), до концентрату металургійного якості, що містить більше 70% Pb, із використанням методу пінної флотації. Методика. Масова проба галеніт-баритової руди вагою близько 100 кг була відібрана з шахти Мал-Хор на північному заході від Хуздару та доставлена в лабораторію переробки мінералів MPRC, PCSIR Lahore для проведення досліджень. Зразок підданий первинному подрібненню із використанням щокової дробарки з наступним вторинним подрібненням із використанням валкової дробарки. Зразок до і після флотації піддавався комплексному хімічному і рентгеноструктурному аналізу (XRD). Флотаційні випробування проводилися на лабораторній флотаційній машині D-12. Після визначення оптимального помелу були проведені випробування для оптимізації щільності пульпи, рН пульпи, швидкості перемішування, кількості доданих реагентів, часу флотації й часу кондиціонування. Результати. Встановлено, що вміст свинцю та барію в поліметалічній руді є достатнім для промислового використання. Отримано оптимальну ступінь подрібнення і відновлення при розмірі подачі 80% мінус 200 меш. Виявлено, що збільшення щільності пульпи дещо знижується при збільшенні В/Т з 20 до 35%, але відновлення збільшується, а максимальне відновлення досягнуто при 30%. При використанні для коригування рН пульпи етілксантата калію, а потім бариту з олеатом натрію, виявлено, що при постійних умовах розміру часток і співвідношення твердої речовини та рідини максимально повторне покриття галену досягається при рН 8.5 і бариту при рН 10.0. Було відзначено, що невелика зміна pH значно змінила ступінь і відновлення. Розкрито вплив швидкості перемішування робочого колеса й відзначено, що оптимальною швидкістю на грубій стадії є швидкість 1100 об/хв, а на стадії очищення – 1000 об/хв. Доведено, що методом пінної флотації з даної руди можна отримати концентрат галеніту із вмістом 77.38% Pb і ступенем відновлення 90.64%, а також концентрат бариту із вмістом 90.23% BaSO4 і ступенем відновлення 80.16%. Наукова новизна. Встановлено характер впливу специфічних речовин, що поліпшують показники про-процесу флотації, які сприяють якісному відділенню цінних компонентів руди від порожніх домішок. Практична значимість. Розроблено принципову схему процесу збагачення галеніт-баритової руди на основі пінної флотації в замкнутому циклі. Отримані концентрати галеніту й бариту відповідають необхідним металургійним і хімічним стандартам та можуть знайти промислове застосування.Цель. Повышение качества низкосортной галенит-баритовой руды, найденной в Хуздарском районе провинции Белуджистан (Пакистан), до концентрата металлургического качества, содержащего более 70% Pb, с использованием метода пенной флотации. Методика. Массовая проба галенит-баритовой руды весом около 100 кг была отобрана из шахты Мал-Хор к северо-западу от Хуздара и доставлена в лабораторию переработки минералов MPRC, PCSIR Lahore для проведения исследований. Образец подвергнут первичному дроблению с использованием щековой дробилки, с последующим вторичным дроблением с использованием валковой дробилки. Образец до и после флотации подвергался комплексному химическому и рентгеноструктурному анализу (XRD). Флотационные испытания проводились на лабораторной флотационной машине D-12. После определения оптимального помола были проведены испытания для оптимизации плотности пульпы, рН пульпы, скорости перемешивания, количества добавленных реагентов, времени флотации и времени кондиционирования. Результаты. Установлено, что содержание свинца и бария в полиметаллической руде является достаточным для промышленного использования. Получена оптимальная степень измельчения и восстановления при размере подачи 80% минус 200 меш. Выявлено, что увеличение плотности пульпы несколько снижается при увеличении В/Т с 20 до 35%, но восстановление увеличилось, а максимальное восстановление достигнуто при 30%. При использовании для корректировки рН пульпы этилксантата калия, а затем барита с олеатом натрия, обнаружено, что при постоянных условиях размера частиц и соотношения твердого вещества и жидкости максимальное повторное покрытие галена достигается при рН 8.5 и барита при рН 10.0. Было отмечено, что небольшое изменение pH значительно изменило степень и восстановление. Раскрыто влияние скорости перемешивания рабочего колеса и отмечено, что оптимальной скоростью на грубой стадии является скорость 1100 об/мин, а на стадии очистки – 1000 об/мин. Доказано, что методом пенной флотации из данной руды можно получить концентрат галенита с содержанием 77.38% Pb и степенью восстановления 90.64%, а также концентрат барита с содержанием 90.23% BaSO4 и степенью восстановления 80.16%. Научная новизна. Установлен характер влияния специфических веществ, улучшающих показатели процесса флотации, что способствовало качественному отделению ценных компонентов руды от пустых примесей. Практическая значимость. Разработана принципиальная схема процесса обогащения галенит-баритовой руды на основе пенной флотации в замкнутом цикле. Полученные концентраты галенита и барита соответствуют металлургическим и химическим стандартам и могут найти промышленное применение.The authors are grateful to Associate Professor, Dr. Zulifqar Ali, Department of Mining Engineering, University of Engineering and Technology (UET), Lahore for his valuable support/ cooperation in X-ray diffraction (XRD) analysis and mineralogical evaluation of ore

Automotive related exposure to particulate air pollution in developing countries cities

Poor urban air quality in developing countriesis a growing public health challenge due to rises in population, industries, urbanization and vehiclesalong with insufficient air quality management. Among the range of air pollutants exposure to particulate matter (PM) is of greatest concern due to its association with chronic obstructive pulmonary diseases. The present study reports traffic related exposure to PM by the roads in Lahore, Pakistan. The measurements of mass and number of PM were carried out by GRIMM analysers (Model 1.108 and Model 1.101) and condensation particle counter (TSI 3781). The heavy metals concentration in PM was determined by Graphite Furnace Atomic Absorption Spectrophotometer (Unicam atomic absorption, Cambridge, UK).The mean hourly average concentration of PM10, PM2.5, PM1 and PM10 – 2.5 at the road siteswas higher during weekdays(305 μg/m3, 84 μg/m3, 61 μg/m3 and 222 μg/m3, respectively) in comparison to the weekend (136 μg/m3, 60 μg/m3, 40 μg/m3 and 76μg/m3, respectively). At the background site the levels in the same size fractions were 206μg/m3, 63μg/m3, 31μg/m3, and 143μg/m3, respectively. Likewise, the number concentration of ultrafine particles was considerably higher at road sites (417,003 #/m3) than the background(97,300 #/m3).The concentration of heavy metals in PM decreased in the following order: Si, Al, Zn, Mn, Cu, Ni, Cd, Pb. Overall, the concentration of PM10, PM2.5 and toxic metals (Mn, Cd, Ni) was substantially higher than guidelines by the WHO. Furthermore, relatively higher levels of the fine fraction (PM2.5 and PM1) in the background reflect their higher residence time and resultant increased risk of exposure to the wider public beyond that of the vicinity to automotive sources. Everyday commuters, mostly on two and three wheelers as well asthe residential population in urban areas are at an enhanced risk of exposure to high levels of particulate pollution

Heavy metal composition of particulate matter in rural and urban residential built environments in Pakistan

Heavy metals in outdoor and indoor airborne particulate matter (PM) and dust in different residential built environmentsat two rural and one urban site in Pakistan were analysed. An eight stage non-viable impactor (Thermo Fisher Scientific Inc., USA) loaded with EMP 2000 glass microfiber filter papers (Whatman, England) was used to collect airborne PM.The indoordust samples (settled dust) were collected from different indoor surfaces (floor, cupboards) in living rooms and kitchens from houses at rural sites. The outdoor samples were collected from courtyards of the houses.At the urban site dust samples were also collected by the roads at 27 different locations around Lahoreand at a background site (University of Veterinary and Animal Sciences).Additionally, samples of dung cake, used as solid fuel, at one of the rural sites were taken.Heavy metals (Si, Al, Zn, Mn, Cu, Ni, Cd, Pb, Co and As) were determined by Graphite Furnace Atomic Absorption Spectrophotometer. At rural site I, in general, the concentrations of metals were higher outdoors than indoors, except for slightly higher indoor levels of Cu (0.85μg/m3 indoor: 0.56 outdoorμg/m3), Si (3.31μg/m3 indoor: 3.17 outdoorμg/m3) and Pb(11.99 ng/m3 indoor: 9.32 outdoor ng/m3). At the rural site II the mean concentration were higher outdoors than indoors, excluding Ni which was considerably higher indoors (55.68 ng/m3) than outdoors (31.91 ng/m3).At the urban site,outdoors, Si had the highest concentration (3.46 μg/m3) followed by Al, Zn, Mn, Cu, Ni, Cd, Pb and Co. Similarly, the indoor levels had a maximum contribution from Si (12.30 μg/m3) followed by Al, Mn, Zn, Cu, Cd, As, Pb, Ni and Co.With reference to dust at rural site I the top five metals outdoors were Si (708 mg/kg), Al, Cu, Zn and Pb (52 mg/kg) while, indoors Al was highest (281 mg/kg), followed by Si, Cu, Zn and Pb (57 mg/kg). At rural site II, both outdoors and indoors, Al (274 mg/kg – outdoor: 266 mg/kg - indoor), Si, Zn, Cu and Pb (61 mg/kg – outdoor: 80 mg/kg - indoor) were the five most abundant metals.The main five metals in decreasing order of their concentration in the road dust around Lahore were Si (686 mg/kg), Al, Cu, Zn and Pb (81 mg/kg). On the other hand, the dust samples from the background site showed Si (345 mg/kg) > Al >Pb> Cu > Zn (73 mg/kg). The airborne metal concentration of Pb was within the guideline value of WHO (0.5 μg/m3) but the levels of Mn, Cd and Ni were higher at all sites than the guidelines proposed by European Commission and WHO highlighting the risk of exposure to toxic metals in non-occupational environments