| OCR Text |
Show maintenance (O&M) costs of the installation and operation of the control system. The EPA has developed some preliminary cost estimates for add-on air pollution control devices, specifically spray dryers and dryer/fabric filter combinations. The results of that study (Ref. 14) were used with the assumptions listed in Table 3 to develop the cost impacts of the addition of these APCDs to a RDF combustor. The capital costs are, of course, highly dependent on the degree of difficulty of retrofitting the equipment into the available space. A retrofit of both a spray dryer and fabric filter equpment can be virtually impossible in some instances. However, assuming some reasonable level of difficulty of the retrofit, the impacts of the addition of the APCD on the tipping fee for the facility described in Table 3 are provided in Table 4. As can be seen in this table, the cost of retrofitting and operating a spray dryer/fabric filter to this selected unit would increase tipping fees from $20/ton to over $32/ton. In other words, a 60 percent increase in tipping fees would be required. The cost of retrofitting with a natural gas cofiring system can be substantially less than a spray dryer/fabric filter retrofit. In Table 3 is also shown the assumptions made for the gas cofiring system. -The impacts on the tipping fee depend primarily on three factors as follows: • The amount of natural gas fired • The cost of natural gas • Whether there is a loss of revenue due to the displacement of municipal waste combustion by natural gas firing. The impact of the cost of retrofitting and operating the natural gas cofiring control scheme is shown in Figure 1. The relative contribution of natural gas usage and costs and the loss of tipping fees due to lack of additional capacity are shown. Thus at a reasonable natural gas cost and usage ($4/ MMBtu and 10 percent respectively) the increase in tipping fee due to the use of natural gas cofiring is less than S8/ton. For lower gas prices and for no loss in revenues due to the existence of extra burning capacity, the tipping 13 |
