The air velocity of starting deposition of biomass particle conveyed by air in the fuel pipes of boilers

Abstract

Biomass fuel is promoted toward a target of net GHG zero emissions in 2050 that Japanese government announced last October 2020. Using biomass pellets in pulverized coal fired power plants are recently increasing. IHI has supplied the co-firing power plants of 30cal% or more biomass pellets with coal. The biomass particles after pulverization by biomass mills are transported to the burners through the fuel pipes by air. Deposition of the biomass particles in a fuel pipe on the way to a burner make a serious impact on the stable combustion and boiler operation. It is important to understand conditions of occurring deposition in order to prevent the deposition of the biomass particles in the fuel pipe. However, various types of pellets are used, and conditions of occurring deposition is depending on the size and shape of the biomass particles. In this test, the transportation of two types of biomass particles is observed by using a transparent horizontal pipe with 30m length. This result suggests that conditions of occurring deposition is different depending on the shape of biomass particles.

Keywords

• woody pellet
• gas-particle two-phase stream
• powder conveying
• pulverized coal fired boiler
• biomass co-firing
• froude number