Chemical Engineering

Azeotropic distillation is a special case of multicomponent distillation used for separation of binary mixtures which are either difficult or impossible to separate by ordinary fractionation. The work is mainly focus on the separation of azeotropic mixtures. Selection of solvent plays an important role in industry to break the azeotropes in easy way. The solvent is selected in such a way that it should break the azeotropic mixture and also should form azeotropic mixture with one of the original component. Determining the existence of homogeneous azeotropes together with their composition, temperature and pressure is important from both theoretical and practical standpoints in the analysis of phase behavior and in the synthesis and design of separation system employing distillation. Different moles of solvent are added to the existence composition of azeotropic mixtures at constant temperature and pressure. Raoult’s law is taken in the modeling to get vapor mixture from given liquid mixture calculated after addition of the solvent to the original azeotropic mixture.

Osmotic dehydration of mango fruits (Mangifer indica L.) is directed towards reduction of its seasonal losses at glut. Effects of sucrose concentrations; 40 to 65°Brix; temperatures; 30 to 50 ºC and time of immersion between 0 to 180 min were studied using samples of diced mango cubes of 2 cm3 dimensions. The measured response variables of water loss, solute gain and performance ratio were subjected to statistical analysis. The results were modelled and optimised on the premise of maximum WL and minimum SG and maximum PR as constraints using the modified distance approach of the response surface methodology (Design Expert 6.08). Optimal osmotic dehydration evaluated were 59.19oBx, 32.06oC and 156.min. of 53.03°Bx sucrose concentration yielded 42.32% WL, 3.41% SG and PR of 10.69 with a desirability of about 89.73%. The results showed that all the input process variables had a significant effect at 5% level of significance (P < 0.05). Optimal process conditions adopted in a semi-continuous pilot plant yielded about 47 (%) water loss and 7.1 (%) solute gain of the initial sample content. The system proved efficient in the treatment of mango with performance ratio in the range of 3 – 7 and could be used in the food industry for the preservation of fruits. More so, the model could be used to predict operational conditions for the OD of other similar fruits. Running title: Optimal osmotic dehydration of mango cubes

The freeze drying behaviour of local cheese was modeled using conservation laws of mass and energy balances such as Fick’s law of mass transfer, Fourier’s law of heat conduction and the Ideal gas equation. The three models developed and simulated are the drying rate, the moisture content and the energy balance models. Three different samples of cheese labeled A, B and C obtained from Bida, Suleja and Kontagora respectively all in Niger State of Nigeria were used to investigate the drying characteristics of local cheese. The analysis of the moisture contents showed that the moisture contents decreased with drying time and that the final moisture content at any time depends on the initial moisture content. Sample A with initial moisture content of 0.0124 kg has a final moisture content of 0.00097kg after 5 hours of drying, while samples B and C with initial moisture contents of 0.009kg and 0.0104kghave their final moisture contents of 0.00001kg and 0.00010kg respectively at the end of 5 hours. When the effect of temperature on moisture loss was studied, it was observed that the moisture loss increased as the freeze drying temperature was increased from 278 to 298K. Results also revealed that moisture loss depends on the initial moisture contents of samples. For this investigation, Samples A, Band C with initial moisture contents of 0.0124kg, 0.0138kg and 0.0104kg have moisture losses of 0.00420kg, 0.00440kg and 0.00363kg respectively at the highest freeze drying temperature of 298K. When the drying rates of samples was investigated, it was found that the drying rates decreased as the moisture contents decreased and which is also a function of the initial moisture contents of samples. The validation of the model was done by carrying out statistical precision analysis which compared the experimental results with those of the output of the models. From the results, the drying rate model showed 75 % agreement with the experimental results (i.e R2 value of 0.75), with a standard error of 3.27X10-5 and a variance of 5.37X10-8, the moisture content model interprets about 98.44 % of the experimental results with a standard error of 7.04X10-4 and the variance of 2.79X10-6, while the energy balance model showed about 99.0 % agreement with the experimental results with a standard error of 2.16X10-5 and a variance of 3.32X10-7.

Greenhouse gases have an important role in understanding earth climate history. Based on these studies greenhouse effect which produces heat due to trapping of heat by greenhouse gases in adjusting earth temperature, Climate change refers to the oscillations in earth global or regional climate in time interval and defines those changes that fluctuate with mean atmospheric conditions or average weather (common) in timescale intervals which fluctuate between decades to million years. Researches and specialists believed that with using of pure energies like solar, windy and heat ground energy and etc, instead of energies cause by fossil fuels will impede of environmental protection implication. So the average volume of light shining at a day is 4 kilowatt H/m2 and the average volume of sunny hour is more than 2800 hour at a year. These changes may have been resulted from earth internal processes or forces beyond it or in recent times due to activities related to the man-made climatically changes. Especially in recent application in the subject of environment policy, the expression of; climate change; often refers to the current changes in new climate.

Carbonic gas by chemical formula CO2 and having acidic property (weak) has many uses as a primal material or intermediate. The first step in produce CO2 gas is diesel combustion. Basically, the conventional methods of fuel combustion, the burning of excess air for complete combustion is used but the CO2 gas production unit must be careful that the air was completely theoretical and no excess air is consider. Because of the separation of CO2 from combustion gases, Mono Ethanol Amine (MEA) solvent is used. This solvent is an amine alcohol with the chemical formula , that because of having alcohol structure is highly sensitive to oxygen And in contact with free oxygen, the alcohol agent becomes to aldehyde and acid That eventually led to the deterioration of the solvent can cause several side effects such as decrease in production rate, the loss of solvent, the phenomenon of corrosion, foam and …This article examines the designed parameters of carbonic gas production unit's solvents in the way of diesel combustion.

The removing dye from wastewaters is a main concern in textile industries letter, press and other commercial manufacturing systems in this decade. This process can make our environment polluted and endanger human being health as they are poisonous and have negative effects on human body. This review paper firstly recognizes synthetic pollution, its characterization and poisonous particles; then, it presents several improvements regarding optimum methods for treating and removing dye from wastewater and finally it suggests some adsorbents that are bio-based and money-saving. A comprehensive category of adsorbents including agricultural waste, bio and natural materials and industrial waste were reported. This paper suggests adsorption method using bio-waste adsorbent as an acceptable method in order to remove dye from waste water. However, further studies are needed to scrutinize the precise results of this approach in industry.

Waste plastics are one of the most promising resources for fuel production because of its high heat of combustion and due to the increasing availability in local communities. Unlike paper and wood, plastics do not absorb much moisture and the water content of plastics is far lower than the water content of biomass such as crops and kitchen wastes. The conversion methods of waste plastics into fuel depend on the types of plastics to be targeted and the properties of other wastes that might be used in the process. Additionally the effective conversion requires appropriate technologies to be selected according to local economic, environmental, social and technical characteristics. In general, the conversion of waste plastic into fuel requires feedstocks which are non-hazardous and combustible. In particular each type of waste plastic conversion method has its own suitable feedstock. The composition of the plastics used as feedstock may be very different and some plastic articles might contain undesirable substances (e.g. additives such as flame-retardants containing bromine and antimony compounds or plastics containing nitrogen, halogens, sulfur or any other hazardous substances) which pose potential risks to humans and to the environment. Pyrolysis is the thermal disintegration of carbonaceous material in oxygen-starved atmosphere. When optimized, the most likely compounds formed are methane, carbon monoxide, hydrogen carbon dioxide and water molecules.the yields of different products depend very much on the process variables. The pyrolytic oil can be blended with the conventional liquid fuels. The pyrolytic waste disposal will also mitigate the problems of environmental pollution.

Reactive Distillation (RD) is the combination of chemical reaction and distillative product separation in single piece of equipment, offers a number of specific advantages over conventional sequential approach of reaction followed by distillation or other separation techniques. The experimental part includes RD experiments in laboratory scale, carefully evaluated database for describing chemical reaction and phase equilibria. The iso-amyl acetate synthesis is also carried out in a packed bed RD column operated in batch and continuous modes. This paper describes an investigation into experimental and simulation work of the heterogeneous esterification of acetic acid with iso-amyl alcohol, catalyzed by an acidic cation –exchange resin. The effects of the variables such as the reflux ratio, vapour rate and feed flow rate on iso-amyl acetate synthesis are studied experimentally. The simulations are based on the equilibrium-stage model approach. The simulation studies are performed in Aspen Plus and MATLAB. Finally results of sensitivity studies using Aspen plus are presented to show the optimum performance of RD column.

Textile industry is the major source of water consumption and wastewater pollution.  There are various treatment techniques to remove textile wastewater pollution.  Textile wet processing unit involves a variety of chemicals comprising a various class of dyes along with huge amount of water resulting from wet processing operation. The conservations of chemical become a most important aspect for environment specially in consideration of the pollution phenomenon and increasing cost of chemicals in order to make the industry much more competitive in the globalize context. For that reason, liquid waste management and waste volume reduction by the product recovery are essential. In the case of India many wet processing industries and about 80% of these are woven fabric dyeing industries are needed to feed the fabric in the garments industries.  For these reasons, effluent treatment planning is a burning question for a wet processing unit. In order to solve these problems as textile technologist we should define many corrective measures.  This paper deals with the effluent standards and different wastages of woven fabric wet processing industries along with reverse osmosis treatment and SDI (Silt Density Index) explained in detail.  It also deals with the various advantages, comparison of RO feed and permeates, RO feed and reject parameters of Silica, Sulphate, Free Chlorine, Chlorides, Silicate and S.D.Index.  RO feed and permeate parameters Si reduced by – 95.46%, SO4 reduced by – 99.19%, Cl¯ reduced by – 94.51%, SiO2 reduced by – 95.22% and SDI reduced by – 100.00%.

In this paper general process design procedure and simulation strategies for reactive distillation (RD) are presented on results are presented. The experimental results obtained from continuous RD column from our previous work are compared with simulation results predicted by three equilibrium stage models of different depths using Aspen plus software. Three types of equilibrium stage models with different complexity are developed, parameterized and compared in simulations in this work. These models are based on the stage concept and use the assumption of vapor–liquid equilibrium on each stage model. Reaction rates for Pseudohomogenous model calculated by our laboratory batch reactor are used for simulation to yield a steady state solution. Finally the VLE data from the databank of Aspen plus is also used to simulate the RD column separately to observe how the results vary with the experimental data and the Aspen plus databank data. It is observed that there is a very good agreement between the results from the Aspen plus databank and the actual column.