Scheduling Multiproduct Chemical Batch Processes using Matrix Representation

Batch process plants are usually designed for the production of specialty and fine chemicals such as paint, food and pharmaceutical to meet specific product requirements as set by current market demand. Batch process plants can be operated as single product in which only one product is produced and multiple products which allow production of more than one product using same batch facility. The economics of the batch process heavily depends on efficient scheduling of the different tasks involved in manufacturing the range of products. The main objective of scheduling is generally to minimize completion time known as the makespan of the batch process. Product sequencing, which is used to set order of products to be produced, has a direct impact on the makespan particularly in the multiple products case. Another effect on makespan is observed for different transfer policies used to transfer the product intermediates between process stages. The generally adopted intermediate transfer policies are (i) zero wait (ZW), (ii) no intermediate storage (NIS), (iii) unlimited intermediate storage (UIS) and (iv) finite intermediate storage (FIS). In the past, the determination of makespan for each transfer policy has been done using a number of mathematical and heuristics approaches. Although these approaches are very efficient and are currently being applied in many chemical process industries but most of them end up with the solution in terms of complex mathematical models that usually lack user interactions for having insights of the scheduling procedure. This motivated the current work to develop relatively simple and interactive alternate approaches to determine makespan. The proposed approach uses matrix to represent the batch process recipe. The matrix is then solved to determine the makespan of a selected production sequence. Rearrangement of the matrix rows according to the varied production sequences possible for the specified batch process recipes enables the makespan to be determined for each sequence. Designer is then provided with the production sequence options with its corresponding makespan from which a selection could be made according to the process requirements

Solvent effectiveness factor: A new correlation to study the influence of solvent, temperature, and stirring rate on synthesis yield of Ionic Liquids

The main objective of this study is to investigate the effect of solvent, temperature, and stirring on synthesis yield of Ionic Liquids (ILs). A representative Ionic Liquid [BMIM][BF4] is prepared using seven different solvents and their influence on percentage yield is explained using a new correlation; solvent effectiveness factor (SEF). The SEF of solvent is governed by nature of solvent, operating temperature and stirring rate. Acetone has the highest SEF 1.275 and affords maximum IL yield 88.11% while toluene has the least SEF 0.674 and produces minimum IL 63.21%. When synthesis temperature is increased from 50 to 80 °C, synthesis yield is substantially increased from 76.7 to 93.08% because rise in temperature increases the SEF from 1.234 to 1.333, mainly due to the decrease in solvent viscosity. Similarly, when stirring rate is increased from 80 to 200 RPM, IL yield slightly increased from 87.37 to 91.35% due to addition of mechanical energy in the reaction mixture which in turn reduced solvent viscosity and increased SEF from 1.278 to 1.297. Keywords: Ionic Liquids, Synthesis, Solvent effectiveness factor, Viscosity, Boiling poin

Convenient Synthesis of Ni-Zn Ferrites from Metal Chlorides

To be updated late

Solid liquid extraction of rice bran oil using binary mixture of ethyl acetate and dichloromethane

The aim of the study is to investigate the potentials of less hazardous, binary mixtures of ethyl acetate (EA) and dichloromethane (DCM) for rice bran oil recovery. Nine solvent mixtures are used with different volumetric ratios of EA/DCM ranging from 0.11 to 9. Solvent mixture with volumetric ratio of 4 (S8) has enabled the maximum oil recovery 88.04 %. The oil extraction yield is enhanced from 76.41 to 89.7 % by increasing the preheating temperature from 40 to 65°C. The other optimized parameters for enhanced oil recovery are: bran particle size <125 μm (obtained with 120 mesh sieve), solvent to bran ratio of 5 mL/g, and stirring time of 15 min. The minimum stirring rate for preventing agglomeration in the mixture and optimized oil recovery is 80 rpm

Development of Algae Guard Façade Paint with Statistical Modeling under Natural Phenomena

Algaecides are chemicals that cause serious health problems. Conventional paints contain algaecides to improve the algae resistance on the paint film. Present research has suggested an environment-friendly paint formulation that focuses on developing algae resistance without having algaecides. In this research, algae growth on newly developed paint is modeled by incorporating dirt resistance of paint and natural phenomena including humidity, temperature, and time, respectively. The fitted Model revealed explained variation of 59.65% in the average algae growth, of which, dirt resistance, humidity, temperature, and some of their interactions play significant role in this variation. The model suggests that the proposed newly developed paint without algaecides is more resistant to algae growth and significantly decreased the average algae growth rate by 0.53% as compared to conventional paints. Keeping the effect of all other factors constant, if dirt resistance of paint (Dc value) increases by one percent, average algae growth decreases by 12.98%; when temperature increases by 1 &#176;C, average algae growth decreases by 22.4%; a positive unit change in the joint linear effect of dirt resistance, temperature, and humidity caused a decrease in average algae growth by 0.0031%. It was also observed that the individual effect of the humidity variable was inversely related with average algae growth. However, the combination of humidity and temperature, humidity and dirt resistance, humidity and time, and the quadratic effect of humidity were found to increase the average algae growth rate. The cubic effect of temperature variable by one degree centigrade resulted in decrease of average algae growth by 0.000907%

Development and Regression Modeling of Dirt Resistive Latex Façade Paint

A highly dirt-resistant paint for building fa&#231;ades without chemicals harmful to nature and the environment would resolve the unattractive disfigurement of building walls caused by dirt. The current ranking of Pakistan in terms of air pollution is 139th. A set of dirt-resistant paint formulae was constructed with the aid of computer programming. From this set, the best dirt-resistant paint formula was explored and identified. The final determination of the optimum formulation was based on statistically planned experiments conducted in the laboratory and in a natural environment. In order to achieve high-quality results, the best available laboratory equipment were used. The results obtained were analyzed and conclusions were drawn using appropriate statistical techniques. The procedure started with the selection of appropriate raw materials and generation of a target population of 543,143 paint formulations by adopting Basic Language computer programming. The average pigment volume concentration (PVC) percentage was computed using theory and found to be 54.98% for the target population paint formulations, verifying the literature results. Experimentation and statistical analysis were performed to compare the classical conventional agitator with the latest lab equipment such as a nano mill, and it was concluded that the nano mill performs better on average than the conventional agitator in the preparation of paint formulations. Hence, the sample of paint formulations was prepared on a nano mill and tested in the laboratory using advanced available technology for the analysis and comparison of paint properties to determine the best paint formulation. The results were analyzed using the Analysis of Variance (ANOVA) technique, and it was concluded that the newly developed paint has the highest dirt resistance on average. The final selected formula, No. 50 (the newly developed paint), was compared with the three best conventional paints available in the Pakistan market in a natural environment for a period of almost one year. A regression model was also constructed to study the effect of environmental factors like time, temperature, and humidity on the dirt resistance of paints. It was found that the newly developed paint formulation is the most environmentally friendly. It performs equally well as one conventional paint and has higher dirt resistance than two other conventional paint formulations containing harmful chemicals. The regression model of dirt resistance involving variables including time, temperature, and humidity shows that these factors significantly affect the dirt resistance of a given paint at a 5% level of significance. For a given paint, 95.34% of the variation in the dirt resistance is due to and explained by the given factors. The regression model is useful for predicting the average dirt resistance of a given paint with a certain level of confidence. The project exemplifies the work of applied research from conceptualization to successful commercialization in the paint industry

Novel polymer matrix composite membrane doped with fumed silica particles for reverse osmosis desalination

Novel polymer matrix composite membranes of cellulose acetate (CA)/polyethylene glycol (PEG) doped with 10–30 wt.% fumed silica particles (FSP) were synthesized. The dissolution casting methodology was used to construct reverse osmosis (RO) membrane which accounts the explicit application for desalination process. The interactions between polymer chains and doped FSP were confirmed by Fourier transform infrared spectroscopy (FTIR). Differential scanning calorimetry thermograms support the physical nature of polymer matrix composite membranes (PMCMs) and an improved glass transition temperature (Tg) from 78.3 to 92.4 °C was observed. The thermal stability of the composite membranes significantly enhanced with the addition of FSP. The typical morphology of PMCM was observed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The 30 wt.% of FSP filled PMCM showed substantial improvement in tensile strength (8.2 MPa) and Young's modulus (854.0 MPa) as compared to the PMCM without FSP. The percentage water content (WC) of the membrane doped with 30 wt.% FSP absorbed more water as compared to the other membranes. It was also noticed that the FSP doped PMCM enhanced the desalination process which was monitored in terms of permeation flux (L/m2·h) and salt rejection (%). The optimum performance of desalination process was shown by 30 wt.% FSP doped PMCM; the permeation flux was 0.66 L/m2·h and salt rejection was 98.4% for the initial feed of 0.35 wt.% NaCl aqueous solution at 25 °C and operating pressure of 4.0 bar (osmotic pressure 2.9 bar)