Pollutants generation characteristics from retired wind turbine blades treated with thermochemical methods

Due to the light weight, high strength, and long blades of wind turbine blades characteristics, it has been a difficult problem for the recycling in the solid waste industry. The thermochemical treatment of retired wind turbine blades is a technology with great potential for large-scale industrial application. In response to the issue of pollutant emissions during the thermochemical treatment process, the pre-treated wind turbine blades thermal conversion experiments were conducted on a tubular electric furnace experimental platform under four different temperatures of 400, 600, 800, and 1000 ℃ during N₂, CO₂, and air atmospheres, respectively. The pollutants emissions containing nitrogen and chlorine were tested. Under the CO₂ and N₂ ambience, HCN and NO are the main nitrogen-containing pollutants. As the temperature increases, HCN gradually increases. At 1000 ℃, HCN-N is the most important nitrogen-containing component, accounting for 88.3% of total nitrogen. However, the proportion of HCl-Cl to total chlorine fluctuates little, maintaining around 5%. Under the air ambience, NO is the main nitrogen-containing pollutant, with a peak concentration of 918.3 × 10⁻⁶. Moreover, the oxygen in the NO mainly comes from the wind turbine blades themselves, rather than the external air. As the temperature increases, HCl and HCN gradually decrease, reaching their maximum at 400 ℃, accounting for 46% and 8.4% of total chlorine and total nitrogen, respectively. CO₂ has a significant promoting effect on the distribution of products, which is related to temperature and composition. CO₂ can significantly promote the generation of HCN and NO at a high temperature of 1000 ℃, but the promotion effect is not significant at a low temperature of 400 ℃. At a low temperature of 400 ℃, CO₂ has a significant promoting effect on the generation of NO₂, while at a high temperature of 1000 ℃, CO₂ has no significant promoting effect on the generation of NO₂. Considering that the oxygen generated by NO mainly comes from the blades themselves, traditional air classification is not effective in reducing nitrogen oxides. Therefore, pilot development requires specialized flue gas nitrogen and chlorine removal devices.