97/03976 Researches on the aerodynamic characteristics of CWS tangentially arranged burners in utility boilers

Abstract

High concentration coal water slurry (CWS) is a new type of coal based liquid fuel developed and applied to replace oil for direct use in industry since the mid-seventies. Industrial tests of coal water slurry combustion in the 20 tons per hour steam output and 60 tons per hour steam output oil fired boilers have been carried out since 1981 in China. Nowaday, a project of burning coal water slurry in the 230 T/H utility boiler in Baiyanghe power plant has been made and several of the retrofit works have been done. This is the first time in this country. The boiler was originally designed based on burning coal. Actually, it keeps on burning oil. It has a cross-section of high length-width ratio (the long-side and short-side are 10.1 m and 7.15 m respectively, the ratio is 1/1.3). Based on the demand of power plant authority and the particularity of boiler construction, the CWM burners must be arranged on two side walls which are shorter than the front and rear wall. As we know, the length-width ratio of cross-section in a tangential fired furnace is generally suggested to be no more than 1/1.25. However, the ratio of this furnace hasmore » already been 1/1.3. If calculating in terms of burner-located points on furnace walls, the length-width ratio is 1/2.13. This obviously contradicts with general suggestion. No furnace aerodynamic information about this arrangement can be found. This arrangement will cause easily the deflection and impingement of the airflow, and it is difficult to form a good airflow distribution. So the retrofitting and design of the burner on the old boiler are very important. For this purpose, the experimental researches in two cold model facilities were carried out carefully. The experimental projects reported in this paper include the aerodynamic characteristic of two shape burners.« less