Using an APK-051 analyzer in a chemical engineering monitoring system

The capabilities of an APK-051 automatic analyzer for directly measuring the standardized indicators used for automatic chemical monitoring and indirectly determining the concentration of ammonia in water coolant are described.     

A Mixed Integer Stochastic Optimization Model for Settlement Risk in Retail Electric Power Markets

Recent changes in the U.S. electric power markets have contributed to volatility in hourly prices and loads. In this paper we consider the position of the electric power retailer who typically contracts with suppliers and end-users and must provide future load requirements to the suppliers. As part of this energy supply chain, the retailer is faced with great uncertainty in both market prices as well as end-user loads. Based on actual data for the PJM market covering Pennsylvania, New Jersey, and Maryland, we develop a probabilistic optimization model to optimize the net profits for the retailer for a forecast time horizon (typically one or more hours) given the cumulative performance in previous time periods (hours). The resulting model is formulated as a mixed integer linear program with binary variables due to the disjunctive nature of certain forward load estimation bandwidth tolerance constraints. In addition, we also provide an existence result to this optimization model. Lastly, we present a numerical example of the optimization model to validate its workings and provide some insight into model sensitivities.     

Computer simulation of the effect of post annealing parameters on the microstructure inhomogeneity of the non-uniformly deformed copper

A computer simulation on the basis of the Finite Element Method and Monte Carlo Model is developed to simulate the microstructure of the non-uniformly deformed copper workpiece after annealing. Using the computer simulation, the effects of annealing time and temperature on the microstructure inhomogeneity of the workpiece are simulated and investigated quantitatively, by defining an Inhomogeneity Factor, to design an annealing program for reducing the microstructure inhomogeneity. The results show that with increasing the parameters of annealing time and temperature, the inhomogeneity is decreased when one of the parameters is constant. Also, at high annealing temperature, the annealing time changes the inhomogeneity slowly compared with which occurs at low annealing temperature. The simulation results agree well with the experimental values.     

Modeling of the inlet zone in the mixed lubrication situation of cold strip rolling

In this paper a method to simulate the oil thickness and length of elastic deformation in the inlet zone of cold rolling has been developed. The mixed film lubrication model was adopted to describe the behavior of the lubricant and asperity deformation. The elastic Von Karman equation was used to describe the elastic deformation of strip in the inlet zone. The length and lubricant film thickness of the inlet zone can be obtained by a numerical method. Results of simulations show that the reduction, rolling speed, back tension have a significant influence on the lubricant film thickness and the inlet zone length.     

The Measurement of pH in Superpure Condensate and Feedwater of Power Units

The change-over to the European standards for the quality of water coolant in power units of thermal and nuclear power stations makes the requirements for the feedwater quality stricter and brings about problems in the measurement of pH. The conventional calibration of a pH-meter against buffer solutions does not yield the measurement accuracy during measurements in infinitely diluted water solutions with electrical conductivity below 0.3 μS/cm. Reliability and validity of pH measurements can be improved by using the readings of automatic conductivity meters and calibration of analyzer in a superpure medium. The first method is implemented in foreign-made instruments, such as FAM Deltacon pH and AMI Deltacon Power. The second method has not yet been developed and is waiting for its implementation in practice. The investigation of the possibility for implementation of these methods using domestic equipment was carried out in the laboratory at the ion-exchange membrane test facility with metering ammonia or carbonic acid solution into deeply demineralized water and was verified under actual operating conditions at the Petrozavodsk Cogeneration Power Station (TETs) and the Kostroma District Power Station (GRES). This investigation resulted in the design of a prototype of a Lider-APK industrial analyzer intended for measurement of pH and concentration of impurities (such as ammonia, sodium, or chlorides) in condensate type waters in the range of pH = 6.0–10.0, and the development of a calibration procedure of industrial bench test pH-meters using ammonia or carbonic acid solutions. The Lider-APK analyzer outperforms its import equivalents and can be used in the automatic chemical monitoring at thermal power stations (TPS). A procedure for calibration of pH-meters in ultradiluted solutions has been first developed and should be verified at industrial facilities. The results of investigation suggest that both methods can improve the reliability of pH measurements in a superpure water coolant using automatic analyzers.     

Optimization of Short Stroke Control Preset for Automatic Width Control of Hot Rolling Mill

Automatic width control is a key issue in hot strip rolling. The edge rolling has been widely used in the roughing stand of hot strip mill to control the width of the slab. However, the edge rolling and consequent horizontal rolling will cause a significant width change in the head part and tail part of the slab, which have to be trimmed before the finishing stands. Based on the width reduction deformation curve of the head and tail along the longitudinal direction of slab, the short stroke control technology has been developed to overcome this problem. In this paper, the finite element method has been used to simulate the unsteady edge rolling process. Three short stroke control curves have been compared in order to obtain the best width control result. The optimized short stroke control curve has been applied to the automatic width control system of industrial hot rolling mill, and good performance is obtained.     

Occurrence of surface defects on strips during hot rolling process by FEM

During a hot rolling process, surface defects on strips can severely affect the quality of the rolled product, particularly for two conditions: (1) there are initial defects on continuous casting slabs that propagate and/or are inherited from those on the surface of rolled steels from upstream rolling processes; and (2) there are no initial defects on continuous casting slabs, and they consequently appear on the surface of rolled steels due to improper rolling technologies. In this paper, the authors present a new 3D finite element model coupled with constrained node failure to understand better the initiation and growth of surface defects on strips during the hot rolling process for case 2. The strip deformation processes were simulated for various rolling reduction ratios and friction coefficients between the roll and the strip. The occurrence of surface defects on strips was modeled under some rolling conditions. The plastic strain distribution in strips and the rolling forces were obtained. The risk of occurrence of surface defects on strips increases as the friction between the roll and strip increases for the same reduction ratio.     

Bio-Based Polyurethanes from Microbially Converted Castor Oil

Bio-based new polyurethanes (PU) were synthesized from microbially converted castor oil. Castor oil was used as a raw material to synthesize 7,10,12-trihydroxy-8(E)-octadecenoic acid (TOD) by the strain Pseudomonas aeruginosa PR3. Subsequently, hexamethylene diisocyanate (HMDI) was used in different ratios and reacted with TOD to produce new PU. Fourier transform-infrared spectroscopy, nuclear magnetic resonance spectroscopy, and gas chromatography/mass spectrometry were used to confirm the identity of TOD. Differential scanning calorimetry, thermogravimetric analysis, and tensile property testing were used to investigate the thermal and mechanical properties of PU. PU synthesized based on TOD had a tensile strength of 45.4 MPa with low elongation at break of 8.16% at an isocyanate/hydroxyl ratio of 2.0. To modify the properties of PU, TOD was blended separately with polyethylene glycol or polycaprolactone diol at different weight ratios before reacting with HMDI. The modified polymer showed improved thermal stability and comparatively higher elongation at break. This is the first study demonstrating the conversion of castor oil into TOD that can be used stand alone or as a blend for PU synthesis.