Chlorine Release during Fixed-Bed Gasification of Coal Chars with Carbon Dioxide

Abstract

CO2 gasification of two kinds of coal chars has been carried out using a fixed-bed quartz reactor mainly at 0.1 MPa and 1000 °C to investigate the behavior of chlorine release during char gasification. For this purpose, an Indonesian sub-bituminous coal or an American bituminous coal is first pyrolyzed at 400 °C/min up to 1000 °C, and the resulting char is gasified in situ at 1000 °C with 50 vol % CO2. The Cl contents of the sub-bituminous and bituminous coal chars are 310 and 1300 μg/g-dry, respectively. Conversion of the Cl to gas species increases with increasing char conversion, and there is an almost 1:1 linear relationship between the two. Chlorine distribution depends strongly on char conversion: yield of water-soluble Cl species increases significantly with increasing conversion up to approximately 50 mass %-daf and then levels off, whereas that of water-insoluble Cl increases more remarkably at the latter stage of the gasification. No measurable amounts of Cl2 are detectable, irrespective of the extent of char conversion, but HCl can be detected significantly. The temperature-programmed desorption run of an activated carbon sorbent recovered after gasification also shows that most of the water-insoluble Cl is thermally stable even at a high temperature of 1000 °C. The formation of water-insoluble Cl-functional groups is discussed mainly on the basis of the results of some model experiments and subsequent Cl 2p XPS measurements.

Catalytic dehydrochlorination of 1,2-dichloroethane to produce vinyl chloride over N-doped coconut activated carbon

“…S7 †), the different chemical states of Cl are represented by four main peaks at 197.3 eV, 199.0 eV, 200.2 eV and 201.7 eV, respectively, corresponded to the Cl 2p 3/2 of Cl À1 , the Cl 2p 1/2 of Cl À1 , the Cl 2p 3/2 of C-Cl bond, and the Cl 2p 1/2 of C-Cl bond. 33,34 Polymer of vinyl chloride is proved to be produced on the catalysts surface during the reaction by the C-Cl bond that exists in the used catalysts. The Cl À1 can be attributed to the HCl product that absorbed on the catalysts.…”

Fate of the Chlorine in Coal in the Heating Process

“…The gas resulting from O 2 bomb combustion was captured in an aqueous solution of (NH 4 ) 2 CO 3 and an absorption spectrophotometer (Hitachi) was used to measure quantities of coal-Cl and of chlorine contained in tar (tar-Cl) and char (char-Cl). 6,13,15,[17][18][19] The reproducibilities of our chlorine-content analyses were ± 5, ± 7 and ± 4% respectively for HCl, tar-Cl and char-Cl.…”

“…6,[13][14][15][16][17][18][19] The correlation coefficient for the calibration curves-constructed for HCl diluted by ultra-high purity N 2 to 20, 50, 100, 200 ppmwas 0.99986. The gas resulting from O 2 bomb combustion was captured in an aqueous solution of (NH 4 ) 2 CO 3 and an absorption spectrophotometer (Hitachi) was used to measure quantities of coal-Cl and of chlorine contained in tar (tar-Cl) and char (char-Cl).…”

An electrochemical DNA biosensor for evaluating the effect of mix anion in cellular fluid on the antioxidant activity of CeO2 nanoparticles

“…Hence, it is think that carbonate group affected the antioxidant activity of CeO 2 nanoparticles as same as phosphate group. Additionally, it should be noted that, no obvious peak was found from 192 eV to 204 eV (Tsubouchi et al, 2013), indicating that there was no chlorine element on the surface of CeO 2 nanoparticles (Fig. 6A).…”