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[摘要]：Potassium, a key nutrient involved in biomass growth, contributes to problematic ash fouling and slagging during combustion. This study was conducted to investigate the combustion behavior of typical rice straw grown in south China, as well as potassium transformation and evolution behaviors. The results showed that the volatile components of the straw have good devolatilization and combustion characteristics, while the residual char is relatively slow to burn out. Under low-temperature conditions, the combustion of char beginning after the devolatilization is almost complete. Chlorine has a higher volatility than alkali metals under combustion conditions. In addition, the migration of potassium has the same tendency as the release of volatiles, indicating that some potassium might evolve together with volatiles at the initial stage of combustion, i.e., in the form of organic potassium. Above 500 degrees C, more inorganic potassium is released to the gas phase, primarily as KCl. These results imply that low-temperature combustion is effective for the retention of potassium within straw ash. A high silica content in straw material is also helpful to constrain inorganic potassium within the biomass residual but might induce agglomeration of the straw ash. |
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