oa South African Journal of Chemical Engineering - Pulverized coal versus circulating fluidized-bed boilers - perspectives and challenges for South Africa
Power generation in South Africa has historically and continues to depend on the use of pulverized coal combustion. The pulverized coal boilers are used by the majority of power stations around South Africa. Although other types of technologies, such as circulating fluidized bed (CFB) are available which are not used for this purpose in South Africa. CFB technology is versatile with the advantage of fuel flexibility compared to pulverized coal technology; it is able to burn coal of high ash and sulphur content and low heating values without affecting the emissions of the greenhouse gases; furthermore it burns other types of solid fuels such as low quality coal; lignite and coal blends. This paper addresses the advantages, limitations and challenges of both technologies with the focus on the behaviour of selected South African coals in CFB. The study was carried out using Russian coal of a high calorific value and low ash content as a reference. We investigated the emission trends of CO, CO2, SOχ and NOχ, HCl and other volatiles. It was found that the emissions was below the limit which didn't exceed 250 ppm for SO2 with a combustion efficiency of 98%.
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