Chemical Engineering
Amin Ahmadpour; Mehdi Jalali
Abstract
Most of the equipment used in material transportation industries, chemical and non-chemical process industries, and even most military equipment use metal base structures. Corrosion of metals, destruction of metal structure or basic alloy is an obvious thing, the consequences of which may be economic, ...
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Most of the equipment used in material transportation industries, chemical and non-chemical process industries, and even most military equipment use metal base structures. Corrosion of metals, destruction of metal structure or basic alloy is an obvious thing, the consequences of which may be economic, human, environmental, or in general, the collection of these losses. All these unpleasant consequences stem from several factors, one of the most important and main mechanisms is the phenomenon of corrosion of metal atoms (loss of valence layer electrons of the metal in the presence of oxidizing agents) and their transformation into ions, which are forced to leave the metal structures and entering the surrounding solution or electrolyte. These phenomena lead to the loss of metal mass, which can manifest itself as a decrease in overall thickness (uniform corrosion) and progressive holes in the depth of the metal (pitting corrosion). In general, corrosion is the cause of mechanical failure and the reduction of structural strength is a target process, because its effects cause the equipment to be destroyed and taken out of service against a mechanical stress higher than the threshold of tolerance, followed by economic losses, human casualties and the environment biologically obtained. Historically, researchers and engineers have always faced the phenomenon of corrosion, and depending on the era in which they lived and the level of science and technology at that time, they used one of the methods to protect the surface against corrosion and other destructive mechanisms of the equipment's materials. Covering the surface with a resistant layer against the penetration and attacks of corrosive and destructive agents is one of the most traditional methods of protecting materials against the destructive behavior of the environment that surrounds a device during its lifetime.
Chemical Engineering
Rozita Kaviani; Amir Arezi
Abstract
The ability of pinch technology to provide a general approach to process design and analysis, but it is incapable of analyzing systems that include power in addition to heat. On the other hand, exergy analysis The main limitation of exergy analysis is the lack of a comprehensive system design method. ...
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The ability of pinch technology to provide a general approach to process design and analysis, but it is incapable of analyzing systems that include power in addition to heat. On the other hand, exergy analysis The main limitation of exergy analysis is the lack of a comprehensive system design method. The combined analysis of punch and exergy, obtained from combining the two mentioned methods, uses both methods to remove both methods’ limitations. In this article, by introducing the Ahvaz Ramin power plant as the studied power plant, an attempt has been made to identify and examine effective improvements using the CPEA(Combined pinch and Exergy Analysis) method. Three proposed correction scenarios have been used to optimize the power plant: 1- Approaching the pins, 2- Increasing the steam in the boiler 3- Decreasing the condenser pressure. The results show that it is possible to increase the studied power plant’s efficiency by about 1.7% by using this method. The fuel consumption of 1569 cubic meters per hour reduces emissions by about 1.7 percent (equivalent to 20 tons per hour). Therefore, the production of pollutants is significantly reduced. Thermoflow software (Steam Pro) simulated the power plant and Aspen Pinch software for CPEA analysis.
Chemical Engineering
Amin Ahmadpour; Masoud Rafiee
Abstract
Propylene is the second most widely product in the world after ethylene. The amount of propylene produced by steam cracking processes as the first source of ethylene and propylene production is limited. New methods of propylene production (dehydrogenation of propane, conversion of methanol to olefins, ...
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Propylene is the second most widely product in the world after ethylene. The amount of propylene produced by steam cracking processes as the first source of ethylene and propylene production is limited. New methods of propylene production (dehydrogenation of propane, conversion of methanol to olefins, conversion of methanol to propylene, etc.) can supply some of its growing demands. The intermediate conversion processes of olefins can meet part of the market demand by converting some of the lighter or heavier olefins from thermal cracking furnaces and by increasing the amount of propylene product. In this paper, we study the technology and economics of several catalytic cracking processes of C4 to C8 carbon olefins. The processes investigated in this report for the catalytic conversion of the by-product of heavier olefins to propylene include Omega, OCP, Superflex, Propylur, and MOI processes.
Chemical Engineering
Saeed Raveshi; Amin Ahmadpour
Abstract
Nowadays energy and electricity production is one of the major concern of governments. Electricity generation by solar systems is considered as one of the alternative for fossil fuels. There is a surge in the use of the solar chimney power plant in the recent years which accomplishes the task of converting ...
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Nowadays energy and electricity production is one of the major concern of governments. Electricity generation by solar systems is considered as one of the alternative for fossil fuels. There is a surge in the use of the solar chimney power plant in the recent years which accomplishes the task of converting solar energy into kinetic energy. In this study a numerical simulation and geometrical parameters optimization of the solar chimney is discussed. In this paper, solar chimney prototype in Manzanares, Spain, as a practical example is used. To explore the geometric modifications on the system performance (output power and efficiency), effect of chimney height, collector radius and collector height is studied. A numerical simulation in this paper were used to evaluate the performance of a solar chimney power plant system, in which the effects of various parameters on the relative static pressure, driving force, power output and efficiency have been further investigated. In order to validate the present work, upwind velocity in the solar chimney was compared with an experimental model.
Chemical Engineering
Hossein Hosseini; Asef Zare
Abstract
Gas turbines are usually designed in such a way that the pressure of hot gases at the exit of the turbine and after the last moving blade is slightly lower than the atmospheric pressure. Therefore, in order to overcome the ambient pressure, a divergent duct is considered at the gas turbine outlet, and ...
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Gas turbines are usually designed in such a way that the pressure of hot gases at the exit of the turbine and after the last moving blade is slightly lower than the atmospheric pressure. Therefore, in order to overcome the ambient pressure, a divergent duct is considered at the gas turbine outlet, and in this way, the exhaust gases, which have a relatively high temperature, are sent to the surrounding atmosphere through the exhaust. The useful output power is transferred to the compressor and then to the generator. Today, the use of gas turbines in power plants and as a generator of electricity is very valuable. In addition, they are widely used in various industries such as space industries, marine platforms, petrochemical industries, etc. These turbines can be useful especially in parts of the electricity industry that require quick installation and commissioning, as well as in cases where the national electricity grid is lost. Speed in construction and installation, low investment cost and low maintenance cost, light weight and the possibility of using multiple fuels are among the advantages of gas turbines compared to other power plants. Current gas turbines are operated with fuels such as natural gas, diesel, low thermal value gases, methane, crude oil, oil. Regarding the disadvantages of these turbines, we can mention the low efficiency and the need for major repairs after fewer working hours and the changes in power and efficiency due to atmospheric changes.
Chemical Engineering
Amin Ahmadpour; Rozita Kaviani
Abstract
Today, the recovery of acetone as an expensive and widely used solvent in the production units of methyl methacrylate, bisphenol A, MTBA, plastics and synthetic fibers is very important. One of the most common recovery methods is the absorption process (solvent separation), which is sometimes used in ...
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Today, the recovery of acetone as an expensive and widely used solvent in the production units of methyl methacrylate, bisphenol A, MTBA, plastics and synthetic fibers is very important. One of the most common recovery methods is the absorption process (solvent separation), which is sometimes used in combination with surface absorption or membrane separation due to its cheapness and availability of knowledge. In this research, it was simulated with Aspen Plus V 7.2 software and the experimental rules of absorption and distillation columns, and with the Levi-Benn model to recover 99.5% of acetone from its mixture with air (10.3-687Mol/hour), the optimal conditions for the absorption tower, 20 equilibrium stages were obtained at atmospheric pressure with effluent and return gas from the separation section. In this situation, the molar ratio of the reflux of the distillation tower is 20.9 with the minimum energy consumption in the partial condenser at the rate of 2.3 Kw and 20 equilibrium stages.
Chemical Engineering
Rozita Kaviani; Ahmad Omidvar; Amir Arezi
Abstract
In recent years, cogeneration systems have been considered to increase the efficiency and optimal use of energy sources for the production of electrical energy and heat energy. Electricity and heat energy cogeneration systems can achieve up to 70% efficiency, and at the realistic and subsidized rates ...
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In recent years, cogeneration systems have been considered to increase the efficiency and optimal use of energy sources for the production of electrical energy and heat energy. Electricity and heat energy cogeneration systems can achieve up to 70% efficiency, and at the realistic and subsidized rates of energy carriers, the beneficiaries of these systems supply the demand and supply sectors. In this study, the optimal working point of a system consisting of several independent units, capable of trading electricity, based on the consumption of various fuels, and utilization of storage tank was determined using genetic algorithm, and modeling accuracy were compared. Other references have also been made. The simulation results show that in the temperate seasons and summer, the cogeneration system meets all electrical and thermal requirements during the 22-23 hours due to the high electricity grid rate and at the end of 24 hours, the total cogeneration cost For almost all seasons 50% less than the conventional production system. It has also been shown that the use of absorption chillers has improved the ratio of electrical and heat loads, and the efficiency of the cogeneration system has increased compared to the previous state, and the heat energy loss has also decreased.
Chemical Engineering
Andi Johnson
Abstract
Mathematical models can be described as a description of a system with mathematical language. This is done by introducing the system under study with a series of equations. Interpreter equations of the system are obtained based on the laws governing that system, boundary conditions, initial conditions ...
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Mathematical models can be described as a description of a system with mathematical language. This is done by introducing the system under study with a series of equations. Interpreter equations of the system are obtained based on the laws governing that system, boundary conditions, initial conditions and physical properties of the system under study. These models make it easier and faster to investigate the effect of various parameters on the system response. Once the mathematical model of a system is obtained, they can be solved analytically or numerically depending on the complexity of the equations. If the model presented is valid for a range of real numbers assigned to variables, it will be a continuous model, and if the model is valid for specific numbers in a range and for all real numbers in that range, it will be a model will be discrete. If the system does not respond to changes in time, the proposed model is called permanent. If the passage of time affects the response of the system, the proposed model is called a non-sustainable model.
Chemical Engineering
Frank Delborty
Abstract
Construction of hydropower, wind, solar, nuclear, geothermal and recycling power plants. It is one of the solutions that the experts in this field of energy production have succeeded so far and have made significant progress in the world by presenting appropriate plans. Iran also did not hold back from ...
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Construction of hydropower, wind, solar, nuclear, geothermal and recycling power plants. It is one of the solutions that the experts in this field of energy production have succeeded so far and have made significant progress in the world by presenting appropriate plans. Iran also did not hold back from this convoy and by building hydropower plants and using the potential of the country's surface water, which amounts to 50. TVVH / y annual energy production by this type of power plants, has taken a step that the vision It puts a light in front of it. Attention and emphasis on sustainable and economic development of energy supply in the national sphere, reduction of greenhouse gases to prevent environmental degradation, expansion of production capacities and increase of energy revenues, replacement of fossil products including oil and gas in power plants, maximum use. The potential of the country's hydroelectric power and ultimately the economic efficiency of this type of power plants during operation to balance the supply of cheap energy to consumers is one of the goals of the energy production sector in our country. In order to implement these goals, the Ministry of Energy based on coherent and purposeful planning in order to realize the full utilization of hydropower generation facilities, which in this context in the framework of energy development and diversification of Iran water and power resources development company, which is organized. He is one of the specialists in the design and construction of hydropower plants, and in the form of this company, he was able to carry out the planned programs in the hydropower sector.
Chemical Engineering
Kim Lo Han
Abstract
In this research, thermal and catalytic pyrolysis and the amount of liquid product obtained from pyrolysis and its composition have been considered. In pyrolysis of each polymer, the amount of liquid product was increased by performing several optimization steps on the reactor. According to studies, ...
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In this research, thermal and catalytic pyrolysis and the amount of liquid product obtained from pyrolysis and its composition have been considered. In pyrolysis of each polymer, the amount of liquid product was increased by performing several optimization steps on the reactor. According to studies, among the three catalysts used, the FCC catalyst produces the most liquid product and the HZSM-5 catalyst releases most of the product as gas due to the small pore size. By gas chromatography test, the percentage of liquid product components, aromatic, olefin, paraffin and naphthenic in the product were obtained and also liquid product components were obtained based on the number of carbons. The results of gas chromatography test show that a significant percentage of the product in pyrolysis with FCC catalyst is olefins. Evaluation can be said that in pyrolysis of rubbers (polybutadiene rubber and styrene butadiene rubber) due to the presence of many double bonds in their structure and the formation of many radicals during pyrolysis, a pyrolysis process will be multi-stage and unlike plastic pyrolysis. The hydrocarbon liquid product is extracted separately and in several stages. The trend of temperature changes in pyrolysis of tires is also increasing and decreasing.
Chemical Engineering
Tayeb Mahmut
Abstract
Referring to the need for three factors of capital, materials and machinery and manpower in the implementation of development projects in the country, he said: "The private sector will never accept investment in projects without considering the profit." Engineer Droudian added: "Since water projects ...
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Referring to the need for three factors of capital, materials and machinery and manpower in the implementation of development projects in the country, he said: "The private sector will never accept investment in projects without considering the profit." Engineer Droudian added: "Since water projects are not feasible in the short term, so the capital is locked for a long time and on the other hand, even after operation, the project does not have a good return." Referring to finding a way to improve the efficiency of projects, he said: 94% of the country's extracted water is consumed in the agricultural, industrial and domestic sectors without any restrictions and disproportionate to the efficiency and price of water input, and according to the water market in Iran, efficiency The desired capital will not be realized after the completion of the project. "Many investors and contractors believe that in the implementation of projects by the private sector, projects are expected to be key in hand so that the private sector can put the projects into operation in the shortest possible time, and as a result, the project," he said. Have an acceptable profitability.
Chemical Engineering
Frank Delborty
Abstract
Central receiver solar systems are capable of generating electricity at high capacities and are more efficient than other similar systems due to their high operating temperature. These types of power plants can be used to supply steam to thermal power plants and also to produce hydrogen. Because, like ...
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Central receiver solar systems are capable of generating electricity at high capacities and are more efficient than other similar systems due to their high operating temperature. These types of power plants can be used to supply steam to thermal power plants and also to produce hydrogen. Because, like other solar systems, only energy from solar radiation is used, there are no problems with greenhouse gas emissions or environmental pollution. These systems are one of the few solar electrical systems that can properly store solar energy and inject the stored energy into the grid when necessary, such as at night or in cloudy weather. The above advantage can be used to store energy and deliver electricity during peak network times. A 100-megawatt power plant with a capacity of 12 hours of energy storage requires only 4,000 square meters of barren land and can well supply the energy needed by 50,000 households. There are millions of square meters of barren land in the central deserts and in the southern, southwestern and northwestern regions of Iran, which can be used as a source for solar energy production compared to hydropower.
Chemical Engineering
Frank Delborty
Abstract
Regarding this question, it should be strongly said that in most cases the answer is yes. Many of these power plants' problems can be solved, and the national ORNL laboratories play an important role in this regard. Choosing the right place for the right design, design and management can lead to further ...
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Regarding this question, it should be strongly said that in most cases the answer is yes. Many of these power plants' problems can be solved, and the national ORNL laboratories play an important role in this regard. Choosing the right place for the right design, design and management can lead to further solutions to these problems. As mentioned earlier, the use of fish ladders, aeration and flow control in large dams is one such solution. Environmental solutions have always existed, meaning that activities can be performed to eliminate or minimize the effects of these projects, or ultimately to compensate for them in some way. In hydropower projects, work can be done to resolve, alleviate, or mitigate the problem before it occurs. ORNL experts have been working for over a decade to effectively evaluate these problems and provide solutions to them. We are currently assisting the US Department of Energy to, with the help of industry, present a plan for the technological development of these power plants in an environmentally friendly manner. Large dams in the Pacific Northwest have stairways for fish that allow adult free fish to enter the river from the ocean to spawn young fish. The fish ladder is a classic example of this. Today, it is found that resident fish in one area also migrate seasonally to spawn to other areas and therefore need a crossing to cross.
Chemical Engineering
Martin Zbuzant
Abstract
In order to optimize the amount of dopant, 3 catalysts with different weight percentages of dopant entered the test medium and it was found that the increase of silver, cerium, nickel. It is one of the factors that accelerates the process of destruction. But this increase works to some extent, and more ...
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In order to optimize the amount of dopant, 3 catalysts with different weight percentages of dopant entered the test medium and it was found that the increase of silver, cerium, nickel. It is one of the factors that accelerates the process of destruction. But this increase works to some extent, and more than this amount will have the opposite effect. In order to optimize the amount of dopant, the oxidative activity of the di benzothiophene compound in a simulated mixture of petroleum derivatives on a set of cerium catalysts as well as nickel deposited on a titanium dioxide substrate was doped with various amounts of Ni dopantin. In general, the oxidant enters the test medium to facilitate degradation. All experiments with the presence of oxidant had a higher efficiency. Therefore, in order to optimize the amount of oxidant, different amounts of them were introduced into the test medium and it was found that increasing the oxidant is one of the factors that accelerates the degradation process, but this increase is somewhat effective and more destructive.
Chemical Engineering
Frank Rebout
Abstract
Fluid molecules adhere to objects due to their viscosity when passing through them, thus causing friction between the fluid and the body. This friction depends on the type of surface, its amount, fluid characteristics and flow. There is a transition zone between the stratified boundary cortex and the ...
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Fluid molecules adhere to objects due to their viscosity when passing through them, thus causing friction between the fluid and the body. This friction depends on the type of surface, its amount, fluid characteristics and flow. There is a transition zone between the stratified boundary cortex and the turbulent region. This practice has been extensively researched in airfoils, especially in Transonic airfoils. For example, research at NASA (ACEE: Air Craft Energy Efficiency) was conducted in the 1970s and 1980s. In this regard, they have succeeded in making airfoils with a border layer up to 60% on the upper edge and up to 50% layer on the lower edge, for the angle swept by the airfoil 26 degrees and Mach number 0.81-0.85 and Reynolds number Chord. The reduction rate of airfoil drag coefficient was 55% compared to the same airfoil with 26 angle and completely turbulent flow. As mentioned before, blowing can delay the onset of disturbance. The physical cause of this will be discussed in the section on secondary fluid. The blowing action can either give more momentum to the fluid and delay the separation, or it can dampen the turbulence and keep the boundary layer layered, thus delaying the transition point. NASA has re-used the airfoil of the previous topic and used blowing in it. The name of these airfoils (ATC: Anti Separtation Tailord Control) has been specified.
Chemical Engineering
Kim Lo Han
Abstract
Heavy polyethylene catalytic pyrolysis with 15% HZSM-5 catalyst was performed at 500 ° C in a semi-continuous stirrer reactor under nitrogen gas. In the first experiment, about 46.7% of the liquid product, 29.2% of the gas product and 4.5% of coke was produced. In the second experiment, with the ...
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Heavy polyethylene catalytic pyrolysis with 15% HZSM-5 catalyst was performed at 500 ° C in a semi-continuous stirrer reactor under nitrogen gas. In the first experiment, about 46.7% of the liquid product, 29.2% of the gas product and 4.5% of coke was produced. In the second experiment, with the changes made on the reactor and condenser, the liquid product output increased by about 8%. In a similar study, the effect of HZSM-5 zeolite catalyst acidity on the catalytic degradation of heavy polyethylene was evaluated. To have HZSM-5 with different acidities, sodium nitrate solution with different concentrations was used. Displacement of protons in the original sample by sodium cations (at room temperature for 4 hours) reduces the acidity of the samples. By adding sodium to HZSM-5 and ion transfer, the acidity of the catalyst decreased and the degradation temperature increased from 390 °C to 555 °C. The gases released from pyrolysis were also analyzed by gas chromatography and it was concluded that the selectivity of volatile products changes with catalytic acidity.
Chemical Engineering
Kim Lo Han
Abstract
Network methods are one of the most widely used groundwater modeling tools that have become widespread and popular over the last two decades. In this research, with a new approach to network methods, these methods are introduced as a numerical model to simulate the movement of groundwater. With the development ...
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Network methods are one of the most widely used groundwater modeling tools that have become widespread and popular over the last two decades. In this research, with a new approach to network methods, these methods are introduced as a numerical model to simulate the movement of groundwater. With the development of this network model, a non-systematic model has been proposed to solve the flow in an arbitrary network. Although many of these problems occur on the surface of the earth, these pollutants enter groundwater after penetrating the earth. After joining the groundwater, these pollutants are transferred by moving groundwater and reach rivers, lakes and wells. On the other hand, the limited groundwater has made the groundwater increasingly important as a source of human drinking water. One of the first steps required to estimate the behavior of groundwater is to find a mathematical model that the application of these models in turn requires the collection of information. By using experimental systems, the cause of errors caused by human error or human ignorance can be greatly reduced and eliminated. For this reason, many studies have been done on issues such as maintenance of a wellhead, design of drinking water supply systems, estimation of movement and transfer of pollutants in the aquifer, etc., and mathematical models for these problems have been presented.
Chemical Engineering
Martin Zbuzant
Abstract
According to international standards, sulfur in fuels used in the transportation industry, as one of the most important polluting industries, should be reduced to around 10 ppmw, while many refineries around the world produce sulfur fuels with more than 1000 ppmw. One of the new and cost-effective methods ...
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According to international standards, sulfur in fuels used in the transportation industry, as one of the most important polluting industries, should be reduced to around 10 ppmw, while many refineries around the world produce sulfur fuels with more than 1000 ppmw. One of the new and cost-effective methods of reducing sulfur among all existing methods is photocatalytic oxidation methods. Another advantage of designed catalysts is that while they are used in the desulfurization process, the oxidation and adsorption processes take place rather than in separate steps (which in turn increases cost and time), due to the structural properties of this. The catalyst of both phases takes place simultaneously and simultaneously during one phase. In reactor experiments, the oxidative desulfurization (ODS) process of model diesel fuel, including the resistant compound of d-benzothiophene in n-shop solvent with 100 ppmw sulfur, was performed under mild operating conditions such as ambient temperature and pressure without hydrogen and the effect of operating parameters such as catalyst mass. Amount and concentration of H2O2 oxidant, type and amount of light radiation, amount of dopant and type of catalyst on the percentage of conversion of sulfur compounds and in other words on the efficiency of the study process and showed that increasing the amount of catalyst, amount and concentration of auxiliary oxidant and the amount of dopant to Certain will increase the efficiency and more than that will reduce the efficiency of the desulfurization process.
Chemical Engineering
Frank Rebout
Abstract
There are many ways to reduce the coefficient of friction as a result of pressure drop in internal flows and thrust force in external flows. For example, film suction, injection of gas bubbles in the boundary layer, use of magnetic fluid, etc., which are mostly intermediate fluids. Polymers are among ...
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There are many ways to reduce the coefficient of friction as a result of pressure drop in internal flows and thrust force in external flows. For example, film suction, injection of gas bubbles in the boundary layer, use of magnetic fluid, etc., which are mostly intermediate fluids. Polymers are among the materials that can be used as intermediate fluids. Due to their ring structure and chain structure, polymer particles stretch and elongate when they are inside the stream. This stretching first absorbs energy from the fluid and does not allow this energy to be used to produce vortices. Second, stretching the polymer chain like a wall prevents the growth of vortices. The higher the molecular mass of the polymer, the greater the drop loss and the lower the critical concentration due to the heavier the polymer. As the concentration of polymer in water increases, the drop curve in terms of discharge towards the horizontal axis of Shifa and gets closer to it. In other words, the friction drops decreases. Percentage drop for 100gr per cubic meter of water is 4.54%, 200gr per cubic meter is 12.78%, 300gr per cubic meter is 27%, 400gr per cubic meter is 30.7% and 500gr per cubic meter is 39.4%, the maximum amount of reduction is.
