Engineering application and economics of LIMB (limestone injection/multistage burners)

The paper describes the use of an EPA LIMB cost model, in conjunction with cost and performance models for flue-gas desulfurization (FGD), to compare these two technologies under similar premises. (NOTE: The performance goals of LIMB, EPA's acronym for Limestone Injection/Multistage Burners for use in SO/sub 2//NOx control for coal-fired boilers, are 50-60% reduction of SO/sub 2/ and NOx for retrofit systems, and achievement of New Source Performance Standards (NSPS) for SO/sub 2/ and NOx for application on new utility boilers. These performance requirements, furthermore, are to be achieved at significantly lower cost than that for FGD, the major control technology alternative.) For a new 500-MW unit burning 1.92%-S coal and achieving control to meet NSPS, costs per ton of SO/sub 2/ removed are estimated to be $1377, $771, and $921 for limestone FGD, lime spray drying, and LIMB using calcitic hydrate, respectively. At 0.48% S in the coal, these costs are estimated at $3715, $1954, and $1134 for limestone FGD, lime spray drying, and LIMB, respectively. For a 300 MW retrofit system, costs per ton of SO/sub 2/ removed for wet limestone FGD and LIMB using calcitic hydrate on a 1.92% S coal application are $1359 and $844, respectively.