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91.
Electrolytic process, employed for manufacturing basic chemicals like caustic soda and chlorine, is highly energy intensive. Due to escalating costs of fossil fuels and capacity addition, the electricity cost has been increasing for the last few decades. Electricity intensive industries find it very difficult to cope up with higher electricity charges particularly with time-of-use (TOU) tariffs implemented by the utilities with the objective of flattening the load curve. Load management programs focusing on reduced electricity use at the time of utility's peak demand, by strategic load shifting, is a viable option for industries to reduce their electricity cost. This paper presents an optimization model and formulation for load management for electrolytic process industries. The formulation utilizes mixed integer nonlinear programming (MINLP) technique for minimizing the electricity cost and reducing the peak demand, by rescheduling the loads, satisfying the industry constraints. The case study of a typical caustic-chlorine plant shows that a reduction of about 19% in the peak demand with a corresponding saving of about 3.9% in the electricity cost is possible with the optimal load scheduling under TOU tariff. 相似文献
92.
K. Suresh Babu 《Chemical engineering science》2009,64(23):4929-4942
The steady state economic optimization to obtain the most economical controllable design of a double feed ideal reactive distillation (RD) column is demonstrated using real coded genetic algorithm. The novelty of the work is in the development of a simple procedure based on steady state criteria for controllability. The optimization is performed for four scenarios corresponding to a sequential increase in the number of design variables. Results show that limiting the optimization search space to only those designs that satisfy the controllability criteria leads to optimized designs that are only slightly (<2%) more expensive than the most economical design without controllability considerations. The former designs however exhibit much better controllability in terms of effectively handling a large through-put change using two-point temperature inferential control and avoiding a steady state transition under open loop operation. Results also show that the location of the fresh feeds is a dominant design variable with designs that do not constrain the feed tray location to be immediately above and below the reactive zone being substantially more economical. 相似文献
93.
H. R. Kotadia N. Hari Babu H. Zhang S. Arumuganathar Z. Fan 《Metallurgical and Materials Transactions A》2011,42(4):1117-1126
The effect of the processing temperature on the microstructural and mechanical properties of Al-Si (hypoeutectic) alloy solidified
from intensively sheared liquid metal has been investigated systematically. Intensive shearing gives a significant refinement
in grain size and intermetallic particle size. It also is observed that the morphology of intermetallics, defect bands, and
microscopic defects in high-pressure die cast components are affected by intensive shearing the liquid metal. We attempt to
discuss the possible mechanism for these effects. 相似文献
94.
95.
T. Lolla J. Siefert S. S. Babu D. Gandy 《Science & Technology of Welding & Joining》2014,19(6):476-486
In recent years, several incidents of cracking and failures have been observed in Stellite (Stellite is a registered trademark of the Deloro-Stellite Corporation) hardfacing used in valves of modern high temperature combined cycle gas fired power plants. These hardfacing layers are applied as an overlay onto a steel substrate, such as CrMo steel (i.e. Grade 22, WC9) or creep strength enhanced ferritic steel (i.e. Grade 91, C12A). Cracking has been observed in valve components at the Stellite/steel interface and in the weld dilution zone formed between the steel and clad. Ultimately, disbonding or delamination of the weld hardfacing from the valve body occurs and has resulted in collateral damage to components in the plant (such as to the turbine) or valve failure. In this study, the microstructure formed near the Stellite/steel interface is investigated. Based on thermodynamic modelling, microstructure formed at these regions is hypothesised and a simple methodology is proposed to predict the occurrence of these failures. 相似文献
96.
97.
Nadendla Hari Babu Wai Lo David A. Cardwell 《Journal of the American Ceramic Society》2000,83(10):2622-2624
The dependence of growth rate on isothermal undercooling and composition has been investigated for Nd-Ba-Cu-O single grains containing various amounts of nonsuperconducting Nd4 Ba2 Cu2 O10 (Nd-422) phase inclusions and fabricated under a 1% O2 in N2 atmosphere using a top seeded melt growth technique. The growth rate along the crystallographic c -direction is observed to exceed that along the a / b direction at all undercooling temperatures and exhibits a maximum for a Nd-422 content of ∼10 mol%. The samples have been examined by optical microscopy and the results interpreted within an established planar solidification model. 相似文献
98.
99.
Kayala Mallikharjuna Babu P Martin Jebaraj M P Chowdiah 《Bulletin of Materials Science》1990,13(3):227-234
A full factorial 23 matrix was designed to study the bending strength, permeability and hoop-stress of investment moulds. A novel method of ethyl-silicate
hydrolysis; two-step hydrolysis, was used. The results indicate that the bending strength is directly proportional to the
quantity of filler material in the slurry. Grain size of stucco material appears to exert the least effect on bending and
hoop strength, whereas permeability increases slightly when coarser grain is used. 相似文献
100.
BACKGROUND: Much of the current research related to the development of in situ nanocomposites of olefins by polymerizing them with metallocenes in the presence of surface‐treated fillers is carried out in the slurry phase. In slurry‐phase methods a large amount of solvent is required and there is always a need of purification of the final product due to the possibility of traces of solvents present in the product. To overcome these drawbacks, to perform solvent‐free metallocene‐catalysed polymerizations with in situ incorporation of inorganic nanoparticles, we have used a gas‐phase polymerization technique as this does not require solvents and also utilizes monomer feed stocks efficiently. RESULTS: The catalyst used for the synthesis of in situ polyethylene nanocomposites by gas‐phase polymerization was nanosilica‐supported zirconocene. The fillers used were Cloisite‐20A, kaolin and nanosilica. Three different in situ polyethylene nanocomposites, i.e. Cloisite‐20A‐filled polyethylene (CFPE), kaolin‐filled polyethylene (KFPE) and nanosilica‐filled polyethylene (SFPE), were prepared by gas‐phase polymerization. The nanocomposites were obtained in the form of fine powder. The polyethylene content in the developed nanocomposites is in the orthorhombic crystalline phase. Using our approach, it is observed that the nanofillers are completely encapsulated by a thin layer of polyethylene. Significantly higher molecular weight polyethylene was formed in the case of KFPE in comparison to CFPE and SFPE. The thermal decomposition temperature, melting temperature and enthalpy are also observed to be higher for KFPE. CONCLUSIONS: The gas‐phase polymerization technique has been successfully carried out for the synthesis of in situ polyethylene nanocomposites. Copyright © 2007 Society of Chemical Industry 相似文献