1. Effect of Ca(OH)2 on the Release Characteristics of HCl during Sludge Combustion
Zhenghui Xu, Jiankang Tan, Chunhua Hu, Ping Fang, Xiang Xiao, Jianhang Huang, Haiwen Wu, Zijun Tang, Dongyao Chen ACS Omega. 2020 Oct 15;5(42):27197-27203. doi: 10.1021/acsomega.0c03286. eCollection 2020 Oct 27.
With the addition of Ca(OH)2, the effects of combustion temperature, moisture, sludge particle size, and chlorine-containing additives on the removal of HCl during sludge combustion were studied. The experimental results showed that combustion temperature and moisture content promoted the formation of HCl and Ca(OH)2 played a key role in the formation of HCl during sludge combustion. Under the best conditions of a sludge particle size of 380-250 μm, moisture content of 5%, temperature of 850 °C, and Ca(OH)2/sludge weight ratio of 3/10, the HCl capture efficiency was 79.81%. In addition, the effect of PVC on the production of HCl was greater than that of NaCl, probably because the lattice energy of NaCl was much higher, indicating that inorganic chlorine was not the main source of HCl. Ca(OH)2 can effectively inhibit the formation of HCl, which had practical guiding significance for the formation of HCl during the sludge combustion, especially the sludge containing chlorine.
2. Dissociative recombination of HCl+, H2Cl+, DCl+, and D2Cl+ in a flowing afterglow
Justin P Wiens, Thomas M Miller, Nicholas S Shuman, Albert A Viggiano J Chem Phys. 2016 Dec 28;145(24):244312. doi: 10.1063/1.4972063.
Dissociative recombination of electrons with HCl+, H2Cl+, DCl+, and D2Cl+ has been measured under thermal conditions at 300, 400, and 500 K using a flowing afterglow-Langmuir probe apparatus. Measurements for HCl+ and DCl+ employed the variable electron and neutral density attachment mass spectrometry (VENDAMS) method, while those for H2Cl+ and D2Cl+ employed both VENDAMS and the more traditional technique of monitoring electron density as a function of reaction time. At 300 K, HCl+ and H2Cl+ recombine with kDR = 7.7±2.14.5 × 10-8 cm3 s-1 and 2.6 ± 0.8 × 10-7 cm3 s-1, respectively, whereas D2Cl+ is roughly half as fast as H2Cl+ with kDR = 1.1 ± 0.3 × 10-7 cm3 s-1 (2σ confidence intervals). DCl+ recombines with a rate coefficient below the approximate detection limit of the method (≲5 × 10-8 cm3 s-1) at all temperatures. Relatively slow dissociative recombination rates have been speculated to be responsible for the large HCl+ and H2Cl+ abundances in interstellar clouds compared to current astrochemical models, but our results imply that the discrepancy must originate elsewhere.