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This paper proposes a fuzzy multiloop control design for a distillation column. The interaction that occurs between the strategic distillation column variables, which represent a major constraint to construct the rules base when the fuzzy multivariable control of the distillation control is considered, are reduced by introducing a compensator in ca...
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Context 1
... order to apply the fuzzy control of distillation columns, the control strategy given in Figure 1 is considered. As shown in Figure 1, a compensator is introduced in cascade with the distillation column that reduces the interaction between the considered control configuration loops. ...
Context 2
... order to apply the fuzzy control of distillation columns, the control strategy given in Figure 1 is considered. As shown in Figure 1, a compensator is introduced in cascade with the distillation column that reduces the interaction between the considered control configuration loops. ...
Context 3
... the two possible control configurations are interactive. Thus, the control strategy given in Figure 1 is indicated to control correctly the distillation column using the multiloop control system. ...
Context 4
... stability of the considered control strategy is guaranteed if the control configuration loops verify the Bristol's condition, that means, the correspondent relative gain to the control configuration pairs must be positive [5], [8][9], [14]. The values of the cascade's RGA below, indicate that the stability of this column using the control strategy shown in Figure 1 is assured, since the diagonally elements corresponds to the considered control configuration pairs are positives. ...
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Citations
... Relative gain method can be used for variable pairing. [15] Control performance of the column is successfully improved by using predictive control, [16][17][18] robust controls, [19,20] and so on. [21,22] Ethylene column, a typical for distillation columns, is characterized by more complicated structures and stricter product quality than common distillation columns. ...
... The value of ECS is calculated by the actual operation data in Table 3, and the value of Q a is 9.048 × 10 4 kJ/mol based on Eqn (9). Thus, h is obtained by Eqn (18). ...
For distillation columns, a temperature is controlled to hold product quality while the column is operated at constant pressure. In practice, absolute stability of temperature and pressure is unachievable, whereas the product quality, namely, product composition, fluctuates with the variation of them. By analyzing phase equilibrium, the composition fluctuation, caused by slight temperature and pressure variation, cannot be ignored for precise distillation column. Thus, a novel approach is proposed to improve the performance of product quality control. For preliminary, the freestanding pressure dynamic model is established via calculating vapor molar holdup. The modeling method is applied to a commercial ethylene column, and the veracity and reliability of the dynamic model is improved. For principal part, the complementary control strategy is proposed on the basis of the improved dynamic behaviors. Besides qualitative analysis, 2 scenes that contain tight control for external disturbance and transition control for internal regulating are discussed to verify the feasibility and progressiveness of product quality control with complementary structure.
... Relative gain method can be used for variable pairing. [15] Control performance of the column is successfully improved by using predictive control, [16][17][18] robust controls, [19,20] and so on. [21,22] Ethylene column, a typical for distillation columns, is characterized by more complicated structures and stricter product quality than common distillation columns. ...
... The value of ECS is calculated by the actual operation data in Table 3, and the value of Q a is 9.048 × 10 4 kJ/mol based on Eqn (9). Thus, h is obtained by Eqn (18). ...
Reducing energy consumption and increasing ethylene recovery rate can effectively optimize the operation of ethylene columns. This paper discusses the trade-off between energy consumption and recovery rate in different scenes. For normal condition, the influences of energy consumption and recovery rate on economic benefits are represented as energy consumption of separation and energy consumption of circulation, while the unseparated ethylene is recycled by the bottom circulatory system. The operation optimization, whose objective is economic benefits, is achieved at the lowest total energy consumption, the sum of energy consumption of separation and circulation. For abnormal condition caused by furnace decoking, the objectives of operation optimization are economic benefits and operability. Operability, affected with remarkable production fluctuation, is quantified by variation of gas and liquid loads. Moreover, the Pareto curve of the multiobjective optimization problem was obtained with total energy consumption and variation of gas/liquid loads as objectives, and the inflection point achieves the equilibrium of economic benefits and operability. Therefore, the balance of recovery rate and energy consumption is crucial to improve economic benefits. Furthermore, moderately operating recovery rate and energy consumption is suitable to maximize economic benefits and operability simultaneously for production fluctuation. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.
... Improved distillation control can have a significant impact on reducing energy consumption to improve the distillation unit's efficiency and operation, improving product quality and protecting environmental resources. However, distillation control is a challenging problem, due to the following factors: process nonlinearity, substantial coupling of manipulated variables, severe disturbances; and no stationary behavior [1][2][3] . ...
... Improved distillation control can have a significant impact on reducing energy consumption to improve the distillation unit's efficiency and operation, improving product quality and protecting environmental resources. However, distillation control is a challenging problem, due to the following factors: process nonlinearity, substantial coupling of manipulated variables, severe disturbances; and no stationary behavior [1][2][3] . ...
Distillation columns are widely used in chemical processes as separation systems in industries. In order to gain better product quality and lower the energy consumption of the distillation column, an effective control system is needed to allow the process to be operated over larger operating ranges. In this study Different control strategies were used to control the distillate and bottom compositions of a packed distillation column to separate the mixture of methanol (CH 3 OH) and water (H 2 O). The tuning of control parameters were determined for PI and PID controllers using three different methods; Internal Model Control (IMC), Ziegler-Nichols (Z.N), and Cohen-Coon (PRC) to find the best values of proportional gain (K C), integral time (τ I) and derivative time (τ D). The Internal Model Control (IMC) method gave better results than that of the other two methods thus it was recommended to be the tuning method in this work. The low values of ITAE of 61.3 for distillate product composition and 54 for bottom composition were obtained which represent the adaptive neuro-fuzzy inference system (ANFIS) method and assure the feasibility of this method as a control strategy among other methods (conventional feedback controllers (PI, PID), artificial neural network (ANN) , adaptive fuzzy logic and PID fuzzy logic controllers). Keywords: distillation, conventional feedback, artificial neural network, adaptive fuzzy Logic and PID fuzzy logic. اﻟﻤﺘﻀﺒﺒﺔ اﻟﻌﺼﺒﯿﺔ اﻟﺸﺒﻜﺔ ﻧﻈﺎم ﺑﺎﺳﺘﺨﺪام اﻟﺘﻘﻄﯿﺮ ﺑﺮج ﻋﻠﻰ اﻟﺴﯿﻄﺮة اﻟﺨﻼﺻﺔ : ﻋﻠﻰ اﻟﺤﺼﻮل وﻟﻀﻤﺎن اﻟﻜﯿﻤﯿﺎﺋﯿﺔ اﻟﺼﻨﺎﻋﺎت ﻓﻲ اﻟﻔﺼﻞ ﻟﻌﻤﻠﯿﺎت واﺳﻌﺔ ﺑﺼﻮرة ﯾﺴﺘﺨﺪم اﻟﺘﻘﻄﯿﺮ ﺑﺮج ﺑﻈﺮوف ﺑﺎﻟﻌﻤﻞ اﻟﺘﻘﻄﯿﺮ ﻟﺒﺮج ﯾﺴﻤﺢ ﻓﻌﺎل ﺳﯿﻄﺮة ﻧﻄﺎم اﻟﻰ ﻧﺤﺘﺎج ﻗﻠﯿﻠﺔ طﺎﻗﺔ ﺑﺼﺮﻓﯿﺎت اﻧﺘﺎج اﻓﻀﻞ ﻣﺨﺘﻠﻔﺔ. ﺗﻢ ﻟﻌﻤﻠﯿﺔ اﻟﺤﺸﻮي اﻟﺘﻘﻄﯿﺮ ﺑﺮج واﺳﻔﻞ اﻋﻠﻰ ﻣﻦ اﻟﺨﺎرﺟﺔ اﻟﺘﺮاﻛﯿﺰ ﻋﻠﻰ ﻟﻠﺴﯿﻄﺮة ﻣﺨﺘﻠﻔﺔ ﺳﯿﻄﺮة طﺮق اﺳﺘﺨﺪام واﻟﻤﯿﺜﺎﻧﻮل اﻟﻤﺎء ﻣﺰﯾﺞ ﺑﯿﻦ اﻟﻔﺼﻞ. ﻟﻤﺴﯿﻄﺮﯾﻦ اﻟﺴﯿﻄﺮة ﻣﺤﺪدات ﺿﺒﻂ وﺗﻢ PI و PID طﺮق ﺛﻼث ﺑﺄﺳﺘﺨﺪام Internal Model Control (IMC) و Ziegler-Nichols و Cohen-Coon ﻟﻠﻜﺴﺐ اﻟﻘﯿﻢ اﻓﻀﻞ ﻻﯾﺠﺎد اﻟﺘﻨﺎﺳﺒﻲ) Kc (اﻟﺘﻜﺎﻣﻞ وزﻣﻦ (τ I) اﻟﺘﻔﺎﺿﻠﻲ واﻟﺰﻣﻦ) (τ D طﺮﯾﻘﺔ ان وﺟﺪ Internal Model Control ﻛﺎﻧﺖ اﻟﻌﻤﻞ ھﺬا ﻓﻲ اﻋﺘﻤﺎدھﺎ وﺗﻢ اﻟﻄﺮق ﺑﻘﯿﺔ ﻣﻦ اﻓﻀﻞ. ﻟﻠﺨﻄﺄ اﻟﺰﻣﻨﻲ اﻟﺘﻜﺎﻣﻞ ﻟﻤﻌﯿﺎر ﻗﯿﻤﺔ اﻗﻞ ﻋﻠﻰ اﻟﺤﺼﻮل ﺗﻢ اﻟﻤﻄﻠﻖ) ITAE (اﻟﻌﺼﺒﯿ اﻟﺸﺒﻜﺔ ﻟﻠﻤﺴﯿﻄﺮ اﻟﻤﺘﻜﯿﻔﺔ اﻟﻀﺒﺎﺑﯿﺔ اﻷﺻﻄﻨﺎﻋﯿﺔ ﺔ) ANFS (ﻟﺒﺮج اﻟﻌﻠﻮي اﻟﻨﺎﺗﺞ ﻟﺘﺮﻛﯿﺰ ﺑﻨﺘﯿﺠﺔ اﻟﺘﻘﻄﯿﺮ 61.3 و 54 اﻷﺧﺮى اﻟﻤﺴﯿﻄﺮات ﺑﯿﻦ ﻣﻦ ﻣﺴﯿﻄﺮ اﻓﻀﻞ اﻧﮫ ﻋﻠﻰ ﯾﺆﻛﺪ واﻟﺬي اﻟﺴﻔﻠﻲ اﻟﻨﺎﺗﺞ ﻟﺘﺮﻛﯿﺰ PDF created with pdfFactory Pro trial version www.pdffactory.com
... The specifications for top and bottom product purity can be met through keeping the tray temperatures within a specified range around their steady state values. Normally, the process is decoupled into a group of independent loops and suitable controller is assigned to each loop [20]- [22]. ...
Multiple Input Multiple Output (MIMO) systems are characterized by significant interactions (i.e.: coupling) between their inputs and their different outputs. The control of MIMO systems is usually implemented using sets of Single Input Single Output (SISO) loop controllers, which requires proper input output pairing and development of decoupling compensation unit. In this paper, a generalized decoupling technique is proposed. The proposed technique uses relative gain array (RGA) to select proper pairing and hybrid genetic and Nelder-Mead algorithm (HGNMA) to estimate the optimal elements' values of the steady state decoupling compensator unit that minimize internal couplings of MIMO system. HGNMA utilizes the concept of minimizing the summation of the integral square outputs (ISOs) of non-proper paired outputs with respect to specific input. One HGNMA is assigned to each input with its own fitness function. Each HGNMA services to minimize its fitness function. The proposed technique is applied on 4 input/4 output two coupled distillation columns process, it proves remarkable success in minimizing the interaction between every input and all outputs except that output has been proper paired with.
The tasks of sound source localization are always of great value in many engineering applications. In these types of localization appliances, several microphone transducers are usually involved in the localization structures. Each of the arrival times of the sound stimulus applied to these microphones is determined individually and sent to the arithmetic-logic sections immediately by which the localization systems could find out positions of the sound sources subsequently. But these appliances always consist of many components, and the looseness of structures may narrow their practical applications. In this paper, a new type of instrument is designed to accomplish the purpose of localizing the sound source by a relatively compact structure. This bionics structure is designed to mimic the localization function of the ears of the parasitoid fly Ormia ochracea, and it consists of three elastic diaphragms, three bars which connected to the diaphragms, and the other mechanical components. The analysis of this structure's dynamic behavior shows that the incident angles of the sound have special relationship to the responses of this instrument, and the incident angles can be estimated by detecting the vibrations of the three elastic diaphragms. Compared with traditional microphone arrays, this instrument has the advantage of compaction and higher integrated level.
