Maximum production rate optimization for sulphuric acid decomposition process in tubular plug-flow reactor

In this paper, optimization and control of a tubular reactor for thermal bulk post- polymerization of styrene have been investigated. By using the reactor mathematical model, static and dynamic simulations are carried out. Based on an objective function including polymer conversion and polydispersity, reactor optimal temperature profile has been obtained. In the absence of model mismatch, desired product characteristic can also be obtained by applying the corresponding reactor wall or jacket temperature profile. To achieve this temperature trajectory, reactor jacket is divided into three zones and jacket inlet temperatures are used as manipulated variables. Effectiveness of the proposed approach has been demonstrated through computer simulation. Furthermore for a special case of model mismatch, a method has been proposed which results in a near optimal profile.

Yield optimization for the van de vusse reaction

The number of pallets circulating in a closed loop production system is an important factor which affects the production rate. If the number is large, pallets stagnate in the system. If the number is small, an idling state occurs frequently in many stages. In both cases the production rate drops. Therefore, it is necessary to control the number of in-process pallets in the system according to the states of pallet flow and stages in order to maximize the production rate. In this paper, we study the effect of pallet input control for a closed loop production system with constant operation cycle time and stage breakdown. First, we model a pallet flow in the system by a Markov model, and analyze the maximum production rate yielded in the system and the optimum policy for pallet input control by a Markov decision process. Next, we present the effectiveness of pallet input control comparing with the uncontrolled system. Finally, in order to investigate the effect of the number of pallets on the production rate, we analyze the production rate and the number of in-process pallets under the optimum policy using the reward function which consists of the production rate and the number of in-process pallets. The main results are as follows. (1) There is the optimum policy for pallet input control which yields the maximum production rate. (2) The pallet control is effective to increase the production rate and decrease the number of in-process pallets. (3) The decrease of the number of pallets monotonously reduces the production rate. However, if the buffer capacity is large, the reduction is very small near the maximum production rate.

Efficiently solving multiple objective optimal control problems

In this investigation, a dynamic simulation and optimization for an auto‐thermal dual‐type methanol synthesis reactor was developed in the presence of catalyst deactivation. Theoretical investigation was performed in order to evaluate the performance, optimal operating conditions, and enhancement of methanol production in an auto‐thermal dual‐type methanol reactor. The proposed reactor model was used to simulate, optimize, and compare the performance of a dual‐type methanol reactor with a conventional methanol reactor. An auto‐thermal dual‐type methanol reactor is a shell‐and‐tube heat exchanger reactor in which the first reactor is cooled with cooling water and the second one is cooled with synthesis gas. The proposed model was validated against daily process data measured of a methanol plant recorded for a period of 4 years. Good agreement was achieved. The optimization was achieve by use of genetic algorithms in two steps and the results show there is a favorable profile of methanol production rate along the dual‐type reactor relative to the conventional‐type reactor. Initially, the optimal ratio of reactor lengths and temperature profiles along the reactor were obtained. Then, the approach was followed to get an optimal temperature profile at three periods of operation to maximize production rate. These optimization approaches increased by 4.7 % and 5.8 % additional yield, respectively, throughout 4 years, as catalyst lifetime. Therefore, the performance of the methanol reactor system improves using optimized dual‐type methanol reactor.

In this paper we study a new estimation method for the maximum production rate in a high quality relay production system and an optimum operation method yieling the production rate. A relay is generally composed of two main parts (Base and Armature) with machining errors occurred in machining processes, so a 'Matching method' must be applied to the system to produce high quality relays. In the 'Matching method' one part is reprocessed using a tool selected according to an assembling error to reduce the assembling error, but the correct tool can not always be selected because the assembling error, which is calculated by machining errors, contains measuring errors. Measuring errors are occurred in measuring processes of machining errors. At first, we propose the estimation method for the maximum production rate and the optimum operation method under two conditions that tools are already set and that tools are not set yet. Next, the effects of machining and measuring accuracies on the maximum production rate and the optimum operation method are investigated. Results show that the proposed method can estimate the maximum production rate and the optimum operation method and that the machining and measuring accuracies both affect the production rate and the operation method.

Optimization of the reactor–regenerator system with catalytic parallel–consecutive reactions

Laminar flow tubular chemical reactors comparison with ideal (plug flow) tubular reactors

The results of a study of the optimization of the experimental conditions for maximum production rate in overloaded elution and displacement chromatography are discussed. This study is based on the use of the equilibrium-dispersive model of chromatography and the competitive Langmuir isotherms to calculate individual band profiles in the elution and displacement modes, and of a simplex algorithm to optimize the production rate. The operating parameters (sample size, mobile phase velocity, and the displacer concentration in the displacement model) and the column design parameters (column length and average particle diameter) are optimized simultaneously. Binary mixtures having relative concentrations 3:1 and 1:3, and separation factors of 1.2 to 1.8 are investigated. One of our major results is that, in both modes of chromatography, the maximum production rate is achieved at very low values of the retention factors, k', much lower than those used in current practice. In all cases, unless k' exceeds greatly that optimum value, the production rate is higher in overloaded elution than in displacement chromatography. This is particularly true for the extraction of a minor component, which is eluted second.

Simultaneous hydrogen and aromatics enhancement by obtaining optimum temperature profile and hydrogen removal in naphtha reforming process; a novel theoretical study

The paper describes the results of a simulation study of a novel method to control water coning in an oil producing well. This method uses a dual completion configuration: above and below OWC. In this configuration, the well section above OWC is completed in the oil zone and produces oil, while the well section completed below OWC in the water-saturated zone serves as a drain to control the rise of the water cone (tailpipe water sink). The physical principle of coning control in this method results from the effect of the water sink upon flow potential between the sink and oil-production perforations. The effect depends upon the water sink flowrate, and it results in suppression of water coning. The objective of this study was to investigate production performance of the well with and without the water sink tailpipe. At first, the water sink's position and flowrate were investigated as they affected the critical production rate of oil, i.e. maximum production rate without the water breakthrough. Next, a comparison was made between the amounts of water produced for greater than critical oil production rates in these two systems. The comparison tests were designed as a series of simulated oil production cycles in a well/reservoir system of known geometry and reservoir properties. The coning behavior of the production system with the tailpipe water sink was mathematically modelled using the flow potential distribution generated by two constant-terminal-rate sinks located between the two linear boundaries and the constant-pressure outer radial boundary. This new model was verified by using the existing and simulated data of water coning in conventional wells and by setting the water sink flowrate at zero, with oil being the only produced fluid. Verification tests were used to select the type of oil reservoir with the thick oil zone and the small dip angle for further comparison studies. In these studies, the amount of produced water with and without the tail water sink was calculated for production rates exceeding the water breakthrough levels in conventional wells. Field data was compared to the results obtained from the water sink model. The study demonstrated the existence of an active mechanism to control water coning with the tailpipe water sink. The mechanism is particularly effective with low flowrate at the sink because it prevents the water cone from breaking through the oil zone into the producing perforations. Also evaluated were the configurations of the well/reservoir system for the tailpipe water sink process. This process yielded less produced water than the conventional method did at the same or higher oil rate.

The adrenal gland production rate of cortisol during ACTH administration and the production rate of 11-desoxycortisol during Metopirone and ACTH administration were studied in a group of dogs. The plasma level of Substance S was a direct function of its adrenal production rate, whereas the plasma level of cortisol was not a direct function of the adrenal cortisol production rate. The maximal adrenal production rate of 11- desoxycortisol during Metopirone block appears to represent a major proportion of the maximal cortisol production rate without this block. Intravenous Metopirone administration over a 7-hr period did not stimulate maximal pituitary ACTH response, as a further increment in response was observed following endotoxin administration. When dogs were treated with ACTH and cortisol for 5 days and tested 36 hr after this therapy, their response to Metopirone was clearly decreased, yet their ACTH response to endotoxin was equivalent to that seen prior to therapy. Endotoxin is a more effective stimulus of ACTH release than Metopirone. Metopirone administration may provide a poor index of pituitary capacity to release ACTH in response to other stimuli.

It is well known that the chemotherapy drug doxorubicin (DOX) is associated with a dose dependent cardiotoxicity, and thus the primary focus of DOX-induced side effects has been the heart. However, there is evidence that DOX also imparts a negative effect on skeletal muscle, but at this point, the nature of this DOX-induced myotoxicity is currently unknown. PURPOSE: To investigate the effects of varying in vivo DOX doses on skeletal muscle function. METHODS: Male rats were randomly assigned to receive 10 mg/kg DOX (DOX1), 12.5 mg/kg DOX (DOX2), 15 mg/kg DOX (DOX3), or control vehicle (CON). Five days following injections, animals were anesthetized and the soleus and extensor digitorum longus (EDL) muscles were excised for ex vivo muscle function analysis. Muscles were maintained in 37°C oxygenated Krebs buffer, and the proximal end of the muscle was mounted to a stationary glass hook while the distal end was affixed to an isometric force transducer. Maximal twitch contraction properties and fatigue rates were determined for all muscles using field stimulating platinum electrodes. RESULTS: Maximal twitch force was significantly reduced in solei from DOX2 and DOX3 when compared to controls (-60% and -72%, respectively, p<0.05). Likewise, DOX2 and DOX3 solei possessed a significantly lower maximal rate of force production (-64% and -72%, respectively, p<0.05) and maximal rate of force decline (-52% and -59%, respectively, p<0.05) when compared to CON. Only EDL muscles from DOX3 possessed significantly different maximal twitch force, maximal rate of force production, and maximal rate of force decline when compared to CON (-67%, -72%, and -60%, respectively, p<0.05). Using a 100 s fatigue protocol, fatigue rate pattern differences were observed in the solei only. Whereas CON solei produced less force than baseline at 70 seconds, DOX1, DOX2, and DOX3 all produced less force than baseline at 30 seconds. CONCLUSIONS: DOX treatment altered muscle function in a dose-dependent manner, and the effects were more profound in the soleus than the EDL. Skeletal muscle dysfunction may, therefore, be contributing to the fatigue experienced by cancer patients receiving DOX which suggests that approaches aimed at minimizing DOX-induced side effects should also target skeletal muscle.

The characteristics of adult bovine adrenocortical cells were studied throughout their life span of 55-65 generations in monolayer culture. Over this period, the cells maintained the capacity to synthesize steroids when tested with repeated maximal doses of ACTH, prostaglandin E1, monobutyryl cAMP, or cholera toxin. Prostaglandin E1 stimulated cAMP production and steroidogenesis, and inhibited DNA synthesis, as measured by incorporation of [3H]thymidine, with dose-response characteristics that did not vary over the first 50 generations in culture. In contrast, the maximal rate of cAMP production stimulated by ACTH declined exponentially at a rate of 7% per generation. In primary and secondary cultures, ACTH stimulated steroidogenesis maximally and inhibited [3H]thymidine incorporation into DNA completely at a half-maximal effective concentration (ED50) of 0.08 nM which was two orders of magnitude less than the ED50 of 8 nM for stimulation of cAMP production. As the ACTH-stimulated maximal rate of cAMP production fell with increasing generation number, the ED50 for ACTH stimulation of steroidogenesis and inhibition of DNA synthesis increased. From about the 20th generation onward, the ability of ACTH to inhibit DNA synthesis maximally declined so that by the 40th generation, cells were completely resistant to the growth-inhibitory effects of ACTH. High-dose ACTH continued, however, to stimulate steroid production maximally over the 50 generations studied. In late passage cells, the ED50 for ACTH stimulation of steroidogenesis was 8 nM, identical to that for cAMP production. Although ACTH-stimulated cAMP production was related to both stimulation of steroidogenesis and inhibition of DNA synthesis, higher cAMP levels appeared required for inhibition of DNA synthesis than for stimulation of steroidogenesis. Mitogenic responses to fibroblast growth factor and to angiotensin II were retained throughout long term growth in culture. The progressive loss of ACTH-responsiveness was specific and a function of aging of bovine adrenocortical cells in culture.

In this paper, the cooling crystallization process in a continuous oscillatory baffled crystallizer (COBC) has been studied. The control objective is to obtain the desired crystal size distribution (CSD) from this process. A population balance equation (PBE) is derived by combining the crystallization mechanism and the COBC's structure characteristics. The simulation of crystallization has been done by combining the PBE with the residence time distribution of the flow, where the residence time distribution is approximated by the tanks-in-series model. In order to get the optimal temperature profile, an optimization formulation is defined. By solving the optimization problem, we can get the optimal temperature profile. The inlet temperature of the cooling water of the jacketed glass tubes is calculated based on energy balance which ensures that the solution temperature along the crystallizer follows the desired cooling temperature profile. A set of simulations has been provided to demonstrate the effectiveness of proposed methods.