Abstract: One of the main technical barriers in biomass gasification development is the formation of tar. After condensation,the tar will not only erode reactors, but affect the following production. So the tar must be eliminated. Tar removal technologies can be divided into two approaches: physical methods and chemical methods. Although the physical methods can eliminate tar very effectively, but during the process they also produce lots of wastewater which pollute the environment. Chemical methods not only can eliminate tar radically,but also increase the conversion rate of the raw material. This paper emphasizes to introduce the chemical methods.

Key words: biomass, tar, gasification, purification