Release Characteristics of Potassium during Biomass Combustion

To investigate the release characteristics of potassium during biomass combustion, experimental studies were conducted on three typical biomass fuels in a reactor with a fixed-bed system. The effects of fuel type, combustion temperature, exposure time, oxygen concentration, and water-washing pretreatment were evaluated. The results show that the K release ratio in corn straw increases with the increment in exposure time when the temperature is between 700 and 900 °C. When burned at 900 °C for 40 min, 17.73% of K is released in the volatile combustion stage, while only 2.62% is released in the char combustion stage. When burned at 700–900 °C, the K release ratios in both corn and wheat straw improve slightly with the elevation in oxygen concentration. Water washing significantly reduces the ratio and the amount of K release from corn straw during combustion. The effect of temperature and atmosphere on K release from the water-washed sample is similar to that for the raw sample.