A theoretical analysis on combustion intensification for blended coal in rotary cement kiln

Blended coal that consists of 70% anthracite and 30% bituminous coal is che aper than pure bituminous coal, but it is very difficult to burn in the rot ary cement kiln. To burn the blended coal, a new kind of burner, which is c alled the burner with velocity difference jets, is used to intensify combus tion. However, combustion intensification and the formation of stable sinte ring layer should be ensured simultaneously in the cement industry. To comp romise the above two aspects, the better burner construction is decided by simulation. The combustion processes in the rotary cement kiln are simulate d by means of improved multi-fluid model for two-phase turbulent flows with reaction. The results of integral simulation show that the ignition of ble nded coal is slower than that of bituminous coal, but the flame of blended coal is longer than that of bituminous coal. Thus the use of blended coal n ot only reduces the cost but also more suits wet kiln. (C) 2001 Elsevier Sc ience Ltd. All rights reserved.