دانلود ترجمه مقاله هدف قرار دادن جایگزینی فرآیند با نمایش دو گانه – مجله الزویر

• فهرست مطالب:

 چکیده
۱ مقدمه
۲ مطالعه موردی
۳ مدل سازی و نمایش نیاز های فناوری و ترمودینامیکی
۳ ۱ پیش گرمادهی با تزریق بخار
۳ ۲ خشک سازی دستگاه کاغذی
۳ ۳ پالایشگاه های اولیه و ثانویه
۴ تلفیق سیستم تبدیل انرژی
۵ تشریح فرایند خمیر و وکاغذ
۵ ۱ هدف حداقل نیاز انرژی
۵ ۲ هدف یابی تلفیق
۶ نتیجه گیری
پیوست a فرمولاسیون مسئله بهینه سازی

• بخشی از ترجمه:

مدل دوگانه نیاز انرژی فناوری و ترمودینامیکی ابزاری ارزشمند برای  مراحل اولیه تحلیل انرژی فرایند است. با استفاده از روش بهینه سازی، فرصت های صرفه جویی در انرژی را می توان از حیث هزینه های  برق و سوخت و با توجه به تولید CHP  کمی سازی کرد/ این خود یک گام مهم در روش باز سازی برای شناسایی و ارزیابی گزینه ها قبل از تحلیل بیشتر است. تحلیل پینچ، آنالیز اکسرژی و روش بهینه سازی برای تعریف اهداف انرژی در سطح سیستم ترکیب شده و از حیث هزینه انرژی بیان می شوند تا نیاز انرژی. حداقل انرژی مورد  نیاز(MER) فرایند با استفاده از مدل دوگانه محاسبه شد که  نیاز ترمودینامیکی فرایند را از اجرای فناوری  تفکیک می کند. فرصت های ریکاوری و بازیابی اکسرژی و انرژی برای بهبود تلفیق سیستم به یک فرایند  بررسی شده است. روش هدف یابی بهینه سازی MILP برای شناسایی بهترین روش تبدیل انرژی و بهینه سازی تولید ترکیبی حرارت و برق(CHP ) استفاده شده است. جایگزینی تزریقات بخار برای ترکیب مخازن با مبدل حرارت ها موجب کاهش MER تا ۱۰ درصد  و افزایش تولید ترکیب  حرارت و برق با ۱ریب ۱٫۷ می شود. بهبود کارایی اکسرژی فناوری خشک سازی کاغذ، امری  مشکل است با این حال نتایج نشان می دهد که این می تواند موجب افزایش بازدهی ۱۲ درصدی برق  بدون تغییر در MER یا حداقل انرژی مورد نیاز شود.

• بخشی از مقاله انگلیسی:

Introduction The optimal design of a utility system should seek to meet the energy requirements of the process that it serves at a minimal cost. Pinch analysis [1] is a mature technology, which has been applied with success to the design of heat exchange networks (HEN) in a broad variety of industries including the pulp and paper industry [2]. In the targeting step performed before the HEN design, the minimum energy requirement to heat and cool all process streams to their functional specifi- cations is first established. However, the method, as first proposed, is not well suited to tackle certain issues encountered when attempting to increase the energy efficiency of a process beyond the maximum internal heat recovery that can be achieved by implementing an optimised HEN. Furthermore, it only deals with the reduction of the heat requirement rather than reducing the process energy expenses. Heuristic rules were first proposed by the developers of pinch analysis to provide guidance for the selection and the appropriate integration in a process of energy converting equipment such as turbines and heat pumps [3,4] while the concept of balanced composite curves [5,6] also broadened the scope of conventional pinch analysis to this type of application and the systematic search for solutions was made possible by developments of adapted optimisation algorithms [7]. The introduction of exergy composite curves [8] brought a new perspective to the identification and evaluation of process enhancement opportunities involving energy upgrading and conversion. Maximising the flowrate of the cheapest utility leads to the creation of utility pinch points [5,6] and underscores the need to analyse simultaneously the utility and the process networks. Graphical techniques become impractical when cycles are concerned. A method based on the use of optimisation techniques [10,12,13] and the corresponding graphical representations [9] has therefore been proposed by Marechal and Kalitventzeff. The cost of energy is a very significant factor in pulp and paper manufacturing [16] and the industry has invested many efforts to reduce it over the year [17]. System closure, i.e. the internal reuse of excess process water, using simulation and observation [20,21] or optimisation techniques [22], often entails a significant reduction in energy cost [18,19] and should be a preliminary to any energy optimisation project. For energy analysis per se, Pinch analysis has now become a routine tool and incursions have been made in extensions of the technique to specific cases such as, temperature mitigation by process streams mixing [23,24] or evaporator trains optimisation [25]. Effect modelling and optimisation concepts have also been applied in design methodologies related to reactive systems [15], or combining energy efficiency and environmental concerns [14,26]. The purpose of this work has been to develop a new method based on pinch analysis techniques and optimisation to identify and evaluate, at a very early stage of the study, the opportunities for reducing energy costs by improving the energy conversion in the process. 2. Illustrative case study The method is applied to an integrated newsprint mill located in Canada. The nominal production of the mill is 1230 odt/d of paper with a feedstock of 1060 odt/d of thermomechanical pulp (TMP) and 170 odt/d of deinked pulp (DIP) also produced on site. A simplified process flow diagram focusing on steam and fresh water requirements is given in Fig. 1. The reference state of the mill was based on information from several sources that have been reconciled using the VALI III software [27] to produce a coherent set of heat and mass balances and determine the hot and cold process streams characteristics. High pressure steam (16.5 bar, 540K) is produced by boilers burning biomass (wood residues) and natural gas (NG). It is in part directly used to meet some mill needs and in part depressurised through turbines and headers to three lower pressure levels: MP (4.5 bar, 421K), LP (3.4 bar, 415K) and VLP (1.7 bar, 408K). As indicated on Fig. 2, steam is then directed to the TMP, DIP, paper making plants and other miscellaneous operations. Steam is also exported to an adjoining saw mill. The turbines produce 2MWe of electricity, while the mill purchases 125MWe. The two most important operations from the energy standpoint are wood chips refining and paper drying. Refining consists in disintegrating wood into individual fibres by forcing the chips between two grooved disks rotating at very high speed. It is a very energy intensive operation. In the mill analysed, the refiners consume 83.7MWe or 6820 kJ/odt, (i.e. 2/3 of the total electrical consumption). The mechanical energy supplied to the refiners is largely dissipated into heat, which evaporates whitewater injected with the chips. In most mills, as in this one, the heat content of this medium steam is recovered through heat exchange with fresh water in the heat recovery unit (Fig. 1) since it contains wood contaminants and cannot be reused directly.

دانلود رایگان مقاله انگلیسی

خرید ترجمه فارسی مقاله