Search

Abstract: Conceptual design using multi‐bed series reactors consisting of catalysts and adsorbent beds was performed for a new SF6 abatement and utilization technology free of toxic chemicals to reduce SF6 emissions and produce valuable products like CaF2 and CaSO4 simultaneously. With process simulation studies using Aspen HYSYS®, comparative studies for a single‐bed reactor (SR‐1), a two‐bed series reactor (SR‐2), and a three‐bed series reactor (SR‐3) revealed that more CaF2 and CaSO4 were produced in multi‐bed series reactors compared to a SR‐1 (SR‐3 > SR‐2 > SR‐1) possibly due to sorption‐enhanced hydrolysis. In addition, lower operating temperatures were observed in multi‐bed series reactors (TSR1 > TSR2 > TSR3) showing the positive effect of using multi‐bed series reactors for a simultaneous SF6 abatement and utilization technology. [ABSTRACT FROM AUTHOR]

In this paper, a multi-stage catalyst-adsorbent reactor consisting of a series of catalyst and adsorbent beds is proposed for an effective tetrafluoromethane (CF4) abatement and conversion of corrosive hydrogen fluoride (HF) to CaF2, a useful chemical. Experimentally, enhanced CF4 conversions were observed in multi-stage catalyst-adsorbent reactors compared to a zero-stage reactor (catalyst bed only) confirming sorption-enhanced CF4 hydrolysis due to selective removal of HF during reaction. In addition, some useful design guidelines to select the number of stages and a proper time to replace adsorbents are presented. To develop a process simulation model to represent experimental data, Aspen HYSYS®, a commercial process simulator, was used providing a proper model to match experimental data quite reasonably. Based on experimental and simulative studies, a three- or four-stage catalyst-adsorbent reactor is recommended for CF4 abatement considering both reactor performance and capital/operating expenditures. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A preliminary techno-economic analysis combining process simulation and economic analysis has been carried out to assess the feasibility of employing a new CF4 abatement and utilization process without HF effluent, where CaO was employed to convert produced HF into CaF2, a useful chemical. Moreover, the effect of employing multi-bed series reactors compared with a single-bed reactor on CaF2 production was analyzed using Aspen HYSYS® based on material and energy balances from process flow diagrams for three systems, a single-bed reactor (S-1), a two-bed series reactor (S-2), and a three-bed series reactor (S-3). From economic analysis to estimate annual operating cost savings for three systems, it was found that multi-bed series reactors (S-2 and S-3) performed better than a single-bed reactor (S-1) due to equilibrium shift by Le Chatelier's principle leading to reduced operating temperatures to produce the same amount of CaF2 as S-1. Consequently, annual cost savings of about 7 to 13% were obtained in S-2 and S-3 compared to S-1 and this can serve as a useful guideline for the efficient system design. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]