توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱Area targeting of Heat Exchanger Network considering fouling
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۷
Area targeting of heat exchanger network is, calculation of the minimum surface for a heat transfer area among hot and cold streams and utililities. Fouling is generally defined as the accumulation of unwanted materials on the surfaces of processing equipment. It is a transient process that begins with a clean heat transfer surface and continues until the point that surface become fouled to the point that the heat exchanger can no longer be used effectively . Fouling ads an additional heat transfer resistance on both tube and shell side of the heat exchanger. As the fluid fouls not only the overall heat transfer coefficient decrease significantly but also pressure drop will also increase significantly. The total cost associated with fouling deposition is significant. Fouling affects both the capital and the operating cost of heat transfer equipment. By implementing an optimal area targeting , the performance of heat exchanger networks prone to fouling can be significantly improved and their operating cost reduced.<\div>

۲Area Targeting of HEN for Shiraz Refinery Atmospheric Distillation Unit with Variable Physical Properties of Crude Oil Consideration
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۸
In the previous studies of area targeting using pinch technology, the effects of physical properties variation (density, thermal conductivity, heat capacity and viscosity),and the optimal allocation of fluids to tube–side or shell–side and variation of heat transfer coefficient (h) as a function of temperature with fixed pressure drop was considered by Omidkhah and Hojjati. In this work Shiraz distillation unit is used as a real industrial case study by using the above method to obtain more actual results of area targeting by sketching heat exchanger network area versus different"ΔTmin". Composite curves were plotted using Cp as a function of temperature in order to applying physical properties variation at targeting stage. Then, they were divided into small temperature intervals. Corresponding Pressure drop and heat transfer coefficient were calculated in each interval. Each real heat exchanger was divided into some thermally small hypothetical heat exchangers. Required area in each small exchanger was determined using rigorous physical property calculations by using MATLAB and HYSYS software. The summation of small interval area would be total network area which can be used to improve heat integration project of distillation tower in Shiraz refinery. The case study which is introduced in this article has an advantage to enable the designer to predict a more reliable and accurate estimation of area targeting results at detail design stage of distillation unit heat exchanger network.<\div>

۳One–dimensional Pseudo–homogeneous Modeling and Simulation of Autothermal Reformer
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۲۰
Autothermal reformer (ATR) usually consists two separate sections: Combustion section and bed section. Namely combustion section model includes atomic mass balances of species, equilibrium equation for water–gas–shift (WGS) reaction and considering some reaction progress for methane steam reforming (MSR). Calculation starts with the assumption of equilibrium for MSR then by departing from equilibrium temperature, concentrations at the end of this section are computed. For bed section, a one–dimensional pseudo–homogeneous model is assumed. Pressure, temperature and concentration gradients along the bed are determined. Effectiveness factors (η) are small values and considered to b constant. It has been shown that their variations have little effect on results. Therefore pseudo–homogeneous model can be used confidently. Intrinsic kinetics is considered for MSR and WGS. Heat losses from reactor wall are taken into account. The results of the model are in good agreement with industrial data available in literature.<\div>

۴Optimization of Steam Network in Shiraz Refinery Utility Systems Using Variable Physical Properties
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۵
Utility system design greatly influences the total site design and operation. In this paper, it has been attempted to apply a method of assimilating solution to determine the optimum pressure level of utility system by considering the variation of physical and thermodynamic properties due to temperature and pressure changes. Mathematical programming methods are also used to reach the maximum profit.<\div>
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