Modeling and Multi-objective Optimization of a Packed Bed Reactor for Sulfur Dioxide Removal by Magnesium Oxide Using Non-dominated Sorting Genetic Algorithm II

Nowadays, protecting the environment is of utmost importance worldwide, and sulfur dioxide is one of the main pollutants in the atmosphere. This work proposes a new method for simultaneous SO2 removal by MgO, and production of magnesium sulfate in a packed bed reactor for which breakthrough curves have been obtained. Furthermore, the effect of important operating parameters, including temperature, SO2 concentration, and gaseous flow rate was investigated. Experiments showed that increasing the temperature improved the breakthrough lifetime, but the increase in concentration and flow rate reduced the lifetime. The experimental results were predicted successfully by applying the Random Pore Model (RPM). Finally, the Non-dominated Sorting Genetic Algorithm II (NSGA II) that is a technique for multi-objective optimization, was employed to determine the best operating parameters for SO2 removal by magnesium oxide in the packed bed reactor. This work is licensed under a Creative Commons Attribution 4.0 International License

Comparison of Sulfur Dioxide Removal Reactions Kinetics by Na2CO3 and Other Different Sorbents from Coal-fired Power Plants

This work deals with kinetic parameters estimation of Na2CO3+SO2 reaction employing sophisticated random pore model. The temperature of experiments ranges from 100 to 250 °C, and various SO2 concentrations are within 0.13–1.12 vol.%. According to the results, the reaction rate concentration dependency follows the fractional function. The values of rate constants and product layer diffusivities are expressed at various temperatures. Finally, it was attempted to describe the significance of this sorbent for SO2 removal. Therefore, the kinetic results of Na2CO3+SO2 reaction were compared with other similar studies on SO2 reaction kinetics with CaO, CuO, and MgO sorbents. It was concluded that Na2CO3 shows advantages of higher rate constants, lower operating temperatures, and less possibility of incomplete conversion problem. The reported kinetic constants are essential for design of flue gas desulfurization reactors, especially in coalfired power plants. This work is licensed under a Creative Commons Attribution 4.0 International License

Simulation and Optimization of Coal Gasification in a Moving-bed Reactor to Produce Synthesis Gas Suitable for Methanol Production Unit

This paper presents process simulation and optimization of coal gasification process in a moving-bed reactor using Pittsburgh No. 8 coal as feed. The system of differential equations for the mass and energy balances was solved using 4th-order Runge-Kutta method and optimized by non-dominated sorting genetic algorithm-II (NSGA-II) method. The simulation was used to predict solid and gas temperature profile and gas composition along the reactor. The simulation results were compared successfully with experimental data relevant to Westfield plant in Scotland. In addition, the effect of operating parameters such as coal-to-oxygen molar ratio, steam-to-oxygen molar ratio, inlet gas temperature, reactor pressure, and oxygen mole fraction in inlet air on amount of synthesis gas (syngas) production, hydrogen to carbon monoxide molar ratio (HCMR) in produced syngas, and coal conversion was investigated. Finally, the reactor performance was optimized to produce the highest syngas production with a HCMR of two using NSGA-II method. This work is licensed under a Creative Commons Attribution 4.0 International License

Simulating and Optimizing Hydrogen Production by Low-pressure Autothermal Reforming of Natural Gas using Non-dominated Sorting Genetic Algorithm-II

Conventional hydrogen production plants consist of natural gas steam reforming to CO+3H2 on Ni catalysts in a furnace, water-gas shift reaction for converting CO into CO2 and CO2 absorption. A new alternative method for highly endothermic steam reforming is autothermal reforming (steam reforming with air input to the reactor) without the need for external heating. In this study, hydrogen production by autothermal reforming for fuel cells (base case) was simulated based on a heterogeneous and one-dimensional model. In addition, the effect of operating variables on the system behavior was studied. Finally, Pareto-optimal solutions for the maximum molar flow rate of the produced hydrogen and methane conversion were determined by NSGA-II. There was a huge increase in the produced hydrogen molar flow to the base case, which showed the importance of optimizing autothermal reformers for hydrogen production

Does a long reference list guarantee more citations? Analysis of Malaysian highly cited and review pPapers

Earlier publications have shown that the number of references as well as the number of received citations are field-dependent. Consequently, a long reference list may lead to more citations. The purpose of this article is to study the concrete relationship between number of references and citation counts. This article tries to find an answer for the concrete case of Malaysian highly cited papers and Malaysian review papers. Malaysian paper is a paper with at least one Malaysian affiliation. A total of 2466 papers consisting of two sets, namely 1966 review papers and 500 highly-cited articles, are studied. The statistical analysis shows that an increase in the number of references leads to a slight increase in the number of citations. Yet, this increase is not statistically significant. Therefore, a researcher should not try to increase the number of received citations by artificially increasing the number of references

The blurring boundaries between synchronicity and asynchronicity:new communicative situations in work-related Instant Messaging

Instant messaging is one of the most popular communication technologies in virtual teams, enabling interactions to intertwine whole working days, thus creating the sense of copresence for team members who are geographically dispersed. Through close linguistic analyses of naturally occurring data from a virtual team, this article discusses the implications of two novel communicative situations enabled by instant messaging: presence information and the persistence of transcript. The preliminary findings of this study indicate that these new communicative situations require the flouting or rethinking of previously existing interactional norms and that communicative practices employed by the team members are not yet conventionalized/normalized, the expectations and interpretations of interactional rituals and timing vary highly, even within the same virtual team

Changing perspectives on the internationalization of R&D and innovation by multinational enterprises: a review of the literature

Internationalization of R&D and innovation by Multinational Enterprises (MNEs) has undergone a gradual and comprehensive change in perspective over the past 50 years. From sporadic works in the late 1950s and in the 1960s, it became a systematically analysed topic in the 1970s, starting with pioneering reports and “foundation texts”. Our review unfolds the theoretical and empirical evolution of the literature from dyadic interpretations of centralization versus decentralization of R&D by MNEs to more comprehensive frameworks, wherein established MNEs from Advanced Economies still play a pivotal role, but new players and places also emerge in the global generation and diffusion of knowledge. Hence views of R&D internationalization increasingly rely on concepts, ideas and methods from IB and other related disciplines such as industrial organization, international economics and economic geography. Two main findings are highlighted. First, scholarly research pays an increasing attention to the network-like characteristics of international R&D activities. Second, different streams of literature have emphasized the role of location- specific factors in R&D internationalization. The increasing emphasis on these aspects has created new research opportunities in some key areas, including inter alia: cross-border knowledge sourcing strategies, changes in the geography of R&D and innovation, and the international fragmentation of production and R&D activities