Optimal Scheduling of the Peirce–Smith Converter in the Copper Smelting Process

Copper losses during the Peirce–Smith converter (PSC) operation is of great concern in the copper smelting process. Two primary objectives of the PSC are to produce blister copper with a shorter batch time and to keep the copper losses at a minimum level. Due to the nature of the process, those two objectives are contradictory to each other. Moreover, actions inside the PSC are subject to several operational constraints that make it difficult to develop a scheduling framework for its optimal operation. In this work, a basic but efficient linear multi-period scheduling framework for the PSC is presented that finds the optimal timings of the PSC operations to keep the copper losses and the batch time at a minimum level. An industrial case study is used to illustrate the effectiveness of the proposed framework. This novel solution can be implemented in other smelting processes and used for the design of an inter-PSC scheduling framework.

Delayed Casting of UHPFRC Elements

Because of high durability and excellent material properties, innovative (thin-walled, shell) structures should be designed. Ultra - High Performance Fiber Reinforced concrete might be used for a specific application with very complex design and very complex shape. Usually, in design UHPFRC structure a reinforcement bars are replaced by a scattered reinforcement. Load bearing capacity in bending of the final shell or thin-walled structure might be influenced by many other factors, including fiber distribution, type and orientation, casting position (for example for up-side down casting) of the shell part of the structure and others. Very significant factor should be a cold joint in term of possible time delay between two batches (simulation of breakdown of the mixer, waiting time to air leakage). At the actual paper focus on an experimental program on cold joint between two batches of fresh UHPFRC poured into the thin wall and deck panels with longitudinal rib. These cold joints are caused by time delay between previous and next batch. Time between two batches differs in range of 10 – 90 minutes.

Modeling of Methyl Methacrylate Polymerization Using MATLAB

This paper presents a modeling of methyl methacrylate (MMA) polymerization with toluene in the presence of azo-bi’s-isobutyronitrile (AIBN) using MATLAB. This work aims to optimize the initial concentration of initiator and the reactor temperature to achieve a maximum monomer conversion in minimum batch time. The optimization of solution polymerization of MMA based on the three-stage polymerization model (TSPM) was performed using ode23t solver. The non-linear polymerization kinetics considered the gel, glass and cage effect to obtain a realistic prediction. The predicted reactor and jacket temperature showed a reasonable agreement with the experimental data, where the error is about 2.7 % and 2.3 %, respectively. The results showed that a maximum monomer conversion of 94 % was achieved at 0.126 kgmol m–3 of the initial concentration of AIBN and 346 K of the initial reactor temperature in 8,951 s (2.5 h).

Optimization of DMC Transesterification Based Biodiesel Production

In this work, two types of optimization problems which are crucially related to batch reactor operation are considered. First problem is to maximize the conversion and second problem is to minimize the batch time. Both problems are solved using sequential quadratic programming (SQP) available in Aspen Plus. The manipulated variables i.e. reactor temperature and amount of palm oil are optimized simultaneously based on the specified objective function and equality constraint. Effect of intervals for both optimization problems are also evaluated in this paper. The results show that in maximizing conversion, the number of intervals did not significantly affect the amount of conversion. Meanwhile in minimizing batch time, the introduction of intervals was positively reduced the reactor temperature but negatively minimize the batch time.

Time requirements in closed and open batch distillation arrangements for separation of a binary mixture

Batch time requirements are provided for the separation of binary zeotropic mixtures in two different multivessel columns (with and without vapor bypass), a non-cyclic two-vessel column and a regular batch column based on dynamic simulations. The first three columns are operated as closed (total reflux) systems and the regular batch column is operated as an open (partial reflux) system. We analyze the effects of feed composition, relative volatility and product specification on the time requirements. The multivessel arrangements perform better than the regular batch column, which requires from 4.00 to 34.67% more time to complete a given separation. The elimination of the vapor bypass in the multivessel column is impractical though it has a positive effect on the batch time requirements. Thus, the multivessel column, with the vapor stream bypassing the intermediate vessel, is proposed as the best candidate for a binary zeotropic mixture with low concentration of light component, low relative volatility and high product purity demand. Furthermore, an experimental multivessel column with vapor bypass is built and the corresponding experiments verify the simulations.

Microalgae harvesting and cell disruption: a preliminary evaluation of the technology electroflotation by alternating current

Some species of microalgae have high productivity and lipid content, which makes them good candidates for biodiesel production. Biomass separation and cell disruption are important steps in biodiesel production from microalgae. In this work, we explored the fundamentals of electroflotation by alternating current (EFAC) with non-consumable electrodes to simultaneously harvest microalgae and disrupt cells from mixed microalgae obtained from waste stabilization ponds. The harvesting efficiency was evaluated using chlorophyll-a and turbidity, which reached removals of 99% and 95%, respectively, during a batch time of 140 min. Cell disruption was evaluated using lipid extraction, and the best results were achieved with a batch time of 140 min, which resulted in a 14% yield. Therefore, EFAC was shown to be an attractive potential technology for simultaneous microalgal harvesting and cell disruption.