توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱The Comprehensive Concept of Urea Thermal Hydrolysis in Industrial Urea Wastewater Treatment
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۸
This paper gives a comprehensive study on urea wastewater treatment by co–current and counter–current configurations of thermal hydrolysis reactors. A model is developed for the two configurations of urea thermal hydrolysis reactors of industrial urea plants. In the proposed model the urea hydrolysis reactors are divided into several continuously stirred tank reactors (CSTRs). The extended electrolytic UNIQUAC equation is used to describe nonideality of liquid phase of NH3–CO2–H2O–urea system under high temperature. The model incorporates reaction rates of urea hydrolysis and takes into account the effects of solution non–ideality and back–mixing on the urea thermal hydrolyser performance. Themodel provides temperature and concentrations distribution of different components in the liquid and vapor phases along the urea thermal hydrolyser. Comparison of two types of hydrolysis reactors shows counter–current mode of hydrolyser isn’t better than co–current mode under each operation condition; but, to achieve the new environmental standards and complete treatment, application of counter–current hydrolyser is necessary. Sensitivity analysis was carried out to assess the effect of the various operating parameters on the two types of hydrolysis reactors performances.<\div>

۲Enhancement of Methanol Production in a Single–Type Reactor with CO Injection
نویسنده(ها): ، ،
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۷
Dynamic simulation of a single–type industrial methanol reactor with CO–rich feed that supplied from the reactor output, has been studied in the presence of long term catalyst deactivation. In this work, the one–dimensional heterogeneous dynamic model has been considered. A single–type methanol reactor is basically a vertical shell and tube heat exchanger. The catalyst is packed in vertical tubes and surrounded by the boiling water. The methanol synthesis reactions are carried out over commercial CuO\ZnO\Al2O3 catalyst. The heat of exothermic reactions is transferred to the boiling water and steam is produced. We investigated the performance of rector with CO injection to feed entrance and compared productm and reactant mole fraction profiles of aforesaid reactor with that of conventional single type (CMR) and membrane methanol reactor (MMR). The simulation results represent 14.24% and 22.93% enhancement in the yield of methanol production in comparison with MMR and CMR, respectively while 5% CO was injected into the 95% of feed. On the other hand, CO is an important cause of pollution and a hazardous material in many industrial processes which must be removed and this method is a suitable method for this case.<\div>

۳Improvement of Wastewater Treatment Section of Old Urea Plant to Satisfy New Environmental Standards
اطلاعات انتشار: ششمین کنگره بین المللی مهندسی شیمی، سال
تعداد صفحات: ۹
In this study, the removal of ammonia and urea from outlet wastewater of treatment section of old urea plant has been investigated. Since the amount of urea and ammonia in outlet wastewater of treatment section of old urea plant is not acceptable due to environmental restrictions and possible to upgrade this wastewater to reuse for boiler feed water or cooling water, an additional thermal hydrolyser– desorber system is used for reduction of urea and ammonia. The extended electrolytic UNIQUAC equation has been used to describe the non–ideality of liquid phase. The proposed model incorporates reaction rate of urea hydrolysis and takes into account the effects of solution non–ideality and backmixing on the reactor performance. The model provides concentration distribution of different components in liquid phase along the height of reactor and in liquid and vapor phases in the desorber. Also the effects of key parameters on the performance of wastewater treatment process have been examined. The result of this work shows that an increasing of inlet temperature of wastewater and steam flow rate improves the urea and ammonia removal efficiency.<\div>
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