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.

This paper attempts to design a vane type feed inlet device to study the flow of vapour in vacuum column containing feed inlet device. The flow of inlet feed has been analysed for pure vapour and mixture streams. The primary function of the flash zone is to separate the entrained liquid feed from the vapour. This is achieved with a feed entry device that changes the direction and reduces the feed velocity as well as by providing adequate height between the wash and the flash zones. Liquid flow behaviour, such as velocity distribution, in the feed inlet device is of considerable importance in determining column performance. Using the volume-average method, a computational fluid dynamics (CFD) model was proposed to describe the liquid flow behaviour in a structured vane type feed inlet device. The values of the geometrical parameters and operation Reynolds number that mark the transitions of flow regime in the inlet device and column are reported. The model of inlet device in column has been developed and meshed in Gambit and the velocity distribution of the flow has been studied at different sections of the column. The proposed study of flow in a column containing feed inlet device has been done in Fluent.

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.

Corrosion from long time ago was one of the biggest problems of gas and oil industry. Corrosion not only cause to high costs of repairs ,but stopping production during repairing and safety matters cause to enormous loss .The importance of covering of underground pipes with plastic material in decade of 1970 continuously has been increased .So that in many cases ,replaced to traditional protector on the base of natural pitch and coal tar .In 1980 more progress was in the field of covering pipes with plastic materials that cause to decisively stabilization of polyethylene and molten connected epoxy as new protector for underground and sea pipe lines .So the aim of continuous extension of plastic materials and covering systems was in direction of making protection tools that are flexible for transferring and resting on extension slope from environment temperature and even preserve their integration in extension range of applied temperature .In this paper we try to study the act of corrosion in external metal pipe lines and even different ways of protection and ways of contrast against mechanical injury and chemical corrosion under soil , by attention to the type of soil.

The unified power quality conditioner (UPQC) is being used as a universal active power conditioning device to mitigate both current and voltage harmonics at a distribution side of power system network. This paper emphasis enhancement of power quality by using UPQC with fuzzy logic controller(FLC)and proportional- integral(PI)controller. The main purpose of the proposed (FLC)is capable of providing good static and dynamic performances compared to PID controller.

Plastics have become an important part of modern life and are used in different sectors of applications like packaging, building materials, consumer products and much more. Each year about 100 million tons of plastics are produced worldwide. Demand for plastics in India reached about 4.3 million tons in the year 2001-02 and would increase to about 8 million tons in the year 2006-07. Degradation is defined as reduction in the molecular weight of the polymer. The Degradation types are (a).Chain end degradation/de-polymerization (b).Random degradation/reverse of the poly condensation process. Biodegradation is defined as reduction in the molecular weight by naturally occurring microorganisms such as bacteria, fungi, and actinomycetes. That is involved in the degradation of both natural and synthetic plastics.  Examples of Standard Testing for Polymer Biodegradability in Various Environments. ASTM D5338: Standard Test Method for Determining the Aerobic Biodegradation of Plastic Materials under Controlled Composting Conditions, ASTM D5210: Standard Test Method for Determining the Anaerobic Biodegradation of Plastic Materials in the Presence of Municipal Sewage Sludge, ASTM D5526: Standard Test Method for Determining Anaerobic Biodegradation of Plastic Materials under Accelerated Landfill Conditions, ASTM D5437: Standard Practice for Weathering of Plastics under Marine Floating Exposure. Plastics are biodegraded, (1).In wild nature by aerobic conditions CO₂, water are produced,(2).In sediments & landfills by anaerobic conditions CO₂, water, methane are produced, (3).In composts and soil by partial aerobic & anaerobic conditions.

The deterioration of the flexible pavements are also due to extreme climatic conditions prevailing in the country in addition to the heavy traffic. The polymer modification of the bitumen can improve the quality of binders and enhance the properties of binders used for the construction of pavements. Ageing of bitumen is one of the principal factors causing the failure of bituminous pavement components due to the prolonged exposure to air and environmental conditions. Ageing are of two types i.e. short term and long term. Short-term ageing occurs when binder is mixed with aggregates in a mixing plant. Long-term ageing occurs after pavement construction and is generally due to environmental exposure and loading. The properties of bitumen mainly depend on the age of bitumen. Therefore there is a need to study the properties of modified bitumen before and after ageing. In this paper the the physical properties of EVA (Ethyl Vinyl Acetate) modified bitumen is discussed, optimum dose is determined and the effect of ageing on the binder prepared using the optimum dose is evaluated.