Flow structure and combustion characteristic of 65 t/h oil shale-fired circulating fluidized bed riser—2: Dilute phase

In this paper, a 65 t/h oil shale-fired circulating fluidized bed (CFB) boiler was put into commercial operation in Huadian of China in 1996 and industrial hot experiment was done for studying the flow structure and combustion characteristic of CFB dilute phase regime. Flow structure and solid flux of dilute phase regime were investigated along both vertical direction and horizontal direction under different boiler loads. Particle-size distribution and carbon content of oil shale combustion residues were obtained. Experimental investigation shows that SO₂ concentration decreases with increasing the furnace height, and NO_X emission can be reduced by adopting staged combustion technology, low-temperature combustion and circulating combustion. Experimental results are valuable for adjusting the 65 t/h boiler and designing large-scale oil shale-fired CFB boiler. At the same time, the experiment lays a foundation for modeling the flow structure, combustion, heat transfer and abrasion of oil shale-fired CFB dilute phase regime.