The working hypothesis for the study was that the main part of the chlorine in biomass is in an inorganic form and therefore should not vaporize appreciably below the melting point of the corresponding salt (around 700 °C) because the vapor pressure over solid salt is negligible. In the study, biomass fuels (sugarcane trash, switch grass, lucerne, straw rape) were subjected to pyrolysis in a flow of nitrogen, and the weight of the residue and its chlorine content were measured and compared to the original fuel. Contrary to the hypothesis, the results showed that during pyrolysis of biomass 20−50% of the total chlorine evaporated already at 400 °C, although the majority of the chlorine was water soluble (in grass 93%) and therefore most probably ionic species. At 900 °C, 30−60% of the chlorine was still left in the char. At 200 °C less than 10% of chlorine had evaporated from the fuel, indicating that the chlorine is not associated with water. Another result was that there was no significant difference in ...

Release of Chlorine from Biomass at Pyrolysis and Gasification Conditions1

Chlorine in coal : A review

Chlorine in coal: an XAFS spectroscopic investigation

Detailed studies have been carried out on the distribution of organic functional groups and inorganic species in as-received (ar) and acid-washed (aw) brown coals using elemental analysis, energy dispersive X-ray analysis (SEM-EDX), X-ray photoelectron spectroscopy (XPS), and Time-of-flight−secondary ion mass spectrometry (TOF−SIMS). Surface concentrations of the various carbon groups, organic oxygen, and inorganic hydroxide were obtained using XPS, but oxygen from clay and quartz, if present, interfered with organic oxygen determinations for the coals. A comparison of ar and aw coals using XPS and SEM-EDX is provided in terms of inorganic and organic sulfur groups. Chloride in these coals is present mainly as acid extractable forms, but small amounts of chloride in the organic matrix were indicated by the elemental analysis of ultra low-ash coals. TOF−SIMS fragments from brown coals were indicative of polymers consisting mainly of single aromatic groups linked by hydrocarbons with carboxyl and phenol fun...

Analytical and Characterization Studies of Organic and Inorganic Species in Brown Coal

In order to understand chlorine chemistry in coal pyrolysis, the dynamics of HCl evolution and changes in chlorine functional forms during temperature-programmed pyrolysis of eight Argonne premium coal samples have been examined with an online HCl-monitoring technique and by the Cl 2p X-ray photoelectron spectroscopy (XPS) method. The rate profiles of HCl evolved show at least three distinct peaks at 390, 520, and 600 °C, and the presence of these peaks depends strongly on the type of coal. The HCl peak at 390 °C appears with four coals alone and becomes considerably small by water washing, whereas the high-temperature peaks above 450 °C observed with almost all of the coals do not change significantly after washing. Yields of HCl up to 1000 °C are in the range of 50–90% in many cases, and the yield tends to decrease with increasing atomic Ca/Cl ratio in coal. The chlorine XPS analyses show that the chlorine in each coal is enriched at the surface and composed of inorganic and organic functional forms. Th...

Geofrey Fynes

Papers

The thermal emission of chlorine-containing compounds from coal following brine and chlorine gas treatments