Experimental evaluation of hydrogen chloride (HCl) absorption by cement raw meals at low temperatures, using fixed-bed tests. Issue 2 (April 2019)

• Record Type: Journal Article
• Authors: Pachitsas, Stylianos; Wedel, Stig; Jensen, Lars Skaarup; Illerup, Jytte Boll; Dam-Johansen, Kim
• Is Part Of: Journal of environmental chemical engineering. Volume 7:Issue 2(2019)
• Publication Date: 2019-04
• Subjects: BET Brunauer Emmett – Teller theory -- D50 mass median diameter of particles -- EDS energy dispersive X-ray spectroscopy -- SEM scanning electron microscope -- FTIR Fourier transform infrared spectroscopy -- L.S. laser scattering -- MFC mass flow controller -- RM-A raw meal from cement plant A -- RM-B raw meal from cement plant B -- tB breakthrough time in the case of inert samples [s] -- ΔtB breakthrough time from active compound [s] -- ΔtB, dry breakthrough time from active compound using dry gas phase [s] -- ΔtB, moist breakthrough time from active compound using moist gas phase [s]; HCl -- Absorption -- Emission -- Cement -- Limestone -- Low temperatures; Chemical engineering -- Environmental aspects -- Periodicals; Environmental engineering -- Periodicals; Chemical engineering -- Environmental aspects; Environmental engineering; Periodicals; 660.0286
• DOI: 10.1016/j.jece.2019.102959
• Languages: English
• ISSNs: 2213-2929

Abstract

Graphical abstract: Highlights: HCl absorption by cement raw meal at low temperatures. Absorption seems to be a surface reaction consuming the active compound surface area. Moisture content of raw meal increases the HCl absorption capacity. Moist gas phase increases the HCl absorption capacity of raw meal below 200 ℃ . Effect of moist gas phase weakens with temperature. Abstract: The HCl absorption by cement raw meals was experimentally evaluated in the temperature range 100-180℃, using a fixed-bed set-up and gas phase HCl content between 50ppmv and 200ppmv. The effects of temperature, gas phase composition and dispersion of raw meal particles on HCl absorption capacity of raw meals were studied. The obtained data are consistent with our interpretation of HCl absorption mechanism based on a surface saturation phenomenon that corresponds to a certain specific HCl absorption capacity of raw meal. The experimentally observed active compound conversions were significantly less than 1%. The dilution of raw meal samples using fused silica with particle size range 50–100 μm increased the apparent HCl absorption capacity of raw meal 10 times due to the elimination of raw meal particle agglomerates. The HCl absorption was slightly enhanced as the temperature was decreased from 180℃ to 100℃ in the case of dry gas phase tests. A dependence of raw meal HCl absorption capacity on the raw meal moisture content was detected at the same experimental conditions. The presence of 5% v/v H2 O in gas phase increased the absorption capacity of raw meal A by 25% at 180℃ and by 61% at 100℃ relative to the absorption capacity from dry gas phase. The presence of 3% v/v O2 and 30% v/v CO2 in gas phase did not have any apparent effect on the HCl absorption in the investigated temperature range.