Calcium hydroxide is a commonly used sorbent in the dry-scrubbing of hydrogen chloride from flue gases. In this study the kinetic parameters for the reaction between gaseous HCl and solid Ca(OH)2 have been obtained at low temperatures in a fixed-bed laboratory reactor. The influence of the operating temperature (323−400 K), HCl concentration (150−1000 ppm), and humidity (0−11% M) was studied. The experimental results show that in the first few seconds a very fast chemical reaction occurs, with a reaction rate constant per unit surface area of solid larger than 10-3 ms-1. This reaction was found to be first order relative to HCl concentration and its mechanism is apparently independent of the presence of moisture. However, the relative humidity of the gas has a major impact on the progress of the reaction: when no moisture is present the reaction stops after a short period of time (2−3 min), with very low maximum solid reactant conversions (<5%). For the experiments with humidified gas an almost complete conversion of Ca(OH)2 was obtained after about 40 min of reaction time. For this case the grain model with product layer diffusion limitations is in very good agreement with the experimental results. The diffusion coefficient in the product layer obtained through this model varied from 10-13 to 10-11 m2 s-1 and the activation energy for this parameter was estimated at ≈19 kJ mol-1 for the range of temperatures studied. A simple linear relationship describes well the effect of relative humidity of the gas on the diffusion coefficient in the solid product layer. In the presence of humidity, the very high conversions of the solid reactant show a good potential applicability to continuous dry-scrubbing of HCl at low temperatures.
Organizations have been showing a growing awareness regarding the importance of corporate sustainability. However, the integration of sustainability concerns in companies' long‐term planning, strategic management, processes, and activities is still challenging, disconnected, and often conducted in isolation. Based on a qualitative exploratory research combining different perspectives found in the literature, the present research presents a theoretical framework that is expected to enhance the adequate development and management of organizational sustainability‐oriented practices — the Integrative Sustainable Intelligence model. This model provides organizational managers with a structured framework to adequately understand, select, implement and assess sustainability promoting actions, based on the development of structural and systematic disruptive tools and involving the exchange of collaborative ideas between organizational stakeholders. The adoption of the Integrative Sustainable Intelligence model is expected to foster change processes and innovations in the search for solutions for sustainability‐oriented business models.
This paper describes a theoretical and experimental study on the use of a reverse-flow cyclone for the dry scrubbing of HCl. Solid lime particles are injected at the cyclone inlet at low temperatures. The inlet gas composition varied in HCl concentration up to 550 ppmv and in water content up to 3.4 vol %. The experimental results show complete HCl removal for solid reactant feeds corresponding to 2−3 times the stoichiometric ratio and for very short residence times (0.05 s). The presence of humidity in the gas was found to be very important for obtaining high HCl removal efficiencies. Significant differences were found in the morphology of the solid products obtained with and without humidification. The experimental results were modeled by considering plug flow for the solid phase and plug flow or perfectly mixed flow for the gaseous phase. In both cases, there is good agreement with the experimental observations. The results suggest that cyclones can be effectively and economically used for acid gas cleaning purposes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.