Abstract: During the pyrolysis process with sawdust as the biomass material，there always occurs serious blockage in heat exchanger for condensation，which influences the collection of bio-oil. Through analyzing the change characteristics of bio-oil viscosity and substances of blockage in the inner tube of heat exchanger，the substance which caused the condenser blockage was the formation of fouling by the heavier components with boiling point about 250℃，which trapped the unseparated char particles in pyrolysis gas. While condensate dropped down along the inner wall of tubes by gravity，surface condensation caused an increase of bio-oil viscosity and meanwhile sticking with fouling particles，so that the thickness of fouling increased gradually，leading to the blockage of tubes.

摘要： 在以锯木屑为原料进行热解过程中，冷凝用换热器经常发生严重的堵塞现象，影响生物油的收集。本文通过分析研究生物油黏度的变化特性以及冷凝用换热器列管内堵塞物质的性质，发现造成冷凝用换热器堵塞的物质是沸点在250 ℃左右的重组分物质俘获热解气中未分离出去的炭粒所形成的堵塞物；冷凝用换热器堵塞的原因是冷凝下来的液体物在重力作用下沿列管内壁面下落时，由于壁面冷凝作用，使生物油黏度增大同时同近壁面的堵塞物质进一步黏结在一起，使污垢层厚不断增加，最终导致列管堵塞。