Abstract: Biomass, as an important clean energy source, has unique advantages in replacing traditional fuels and reducing carbon emissions. The development of direct combustion biomass power generation technology for circulating fluidized bed boilers is of great significance for promoting China's green energy cycle development and carbon neutrality. China has abundant reserves of yellow straw biomass, but due to its inherent characteristics such as high alkalinity and high chlorine, it is more difficult to utilize it as a power generation raw material. Currently, boilers using yellow straw biomass often suffer from pollution and corrosion, which affect the long-term stable operation of the boiler. Taking a 220 t/h high-temperature and high-pressure cfb boiler that uses a large proportion of yellow straw biomass as an example, the boiler is designed with 50% yellow straw and 50% ash straw as fuel. It is expected to utilize 457 000 tons of biomass annually, reducing 370 000 tons of CO₂ emissions. A series of measures have been proposed to solve the problem of contamination and corrosion affecting the reliability of boilers that burn a large proportion of yellow straw biomass. A lower bed temperature design is adopted to prevent coking in the furnace and suppress alkali metal precipitation from the source. The upper heating surface of the tail flue adopts a large pitch low wall temperature water-cooled evaporation tube bundle to quickly reduce the inlet flue gas temperature of the downstream heating surface, avoid the contamination sensitive temperature range, and reduce the furnace fluidization speed and tail heating surface flue gas flow rate. The tail heating surface is arranged in a row to reduce flue gas disturbance. Multiple high-pressure blowing air and coke removal air are added to the inlet flue of the cyclone separator and the riser of the material return device respectively to solve the contamination problem; Arrange the high-temperature stage superheater with a wall temperature greater than 480 ℃ in the furnace, and use the large amount of circulating materials in the main circulation loop to wash away and prevent alkali metal chlorides from depositing on the heating surface and causing corrosion. All heating surface tubes are made of SA-213TP347H material, and the low-temperature stage superheater at the tail can be made of 12Cr1MoVG material to solve the problem of high-temperature corrosion; By using the special structure of "External air preheater + Graded economizer" instead of conventional air preheater, the exhaust temperature can be controlled by controlling the feedwater flow rate of the air preheater. Under the same exhaust temperature, the metal wall temperature of the final heating surface can be significantly increased, reducing the possibility of chloride and sulfuric acid condensation and precipitation on the final heating surface, and solving the problem of low-temperature corrosion.