Catalysts operating cost estimation

The capital cost of an integrated SCR unit for a new 1,000 tonne/day plant is estimated to be 1.5% of the total capital cost of the nitric acid plant. This cost includes the cost of the SCR catalyst but excludes spare parts. The capital cost of an end-of-pipe SCR unit for an existing 1,000 tonne/day plant is estimated to be 3% to 6% of the total capital cost of the nitric acid plant. But this is very dependent on the type of nitric acid process. The SCR will increase operating costs by 1.1% when NOx in the tail gas is reduced from 1,000 ppmv to 200 ppmv. The maintenance cost of the SCR unit is typically 2.5% of the capital cost97. 

Catalytic distillation essentially eliminates catalyst fouling because the fractionation removes heavy coke precursors from the catalyst zone before coke can form and foul the catalyst bed. The estimated ISBL (inside battery limits) capital cost for 35,000bpd CDHydro/CDHDS unit with 92% desulfurization is US 25 million, and the direct operating cost including utilities, catalyst, hydrogen, and octane replace-... 

Estimated investment costs for Cases A and B are shown in Table III. Investment costs are based upon erection of the plant on the U.S. Gulf Coast. Erected costs include the first catalyst charge but exclude associated off-site facilities, crystallizer, and royalty charges. Estimated operating costs are shown in Table IV. Utility costs in dollars per calendar day are based upon use of electric drivers for pumps and compressors, maximum use of air coolers, and fired furnaces for reboiling the light ends... 

Working capital funds, Cwc. are needed to cover operating costs required for the early operation of the plant, including the cost of the inventory and funds to cover accounts receivable. Because they involve the costs of the raw materials and the values of the intermediates, products, and byproducts, the working capital is normally estimated in connection with the calculation of the operating Cost Sheet , which is presented in Table 17.1 and discussed in Section 17.3. Note that funds are usually allocated for a spare charge of catalyst, often kept in a warehouse, as a backup in case an operating problem causes the catalyst to become ineffective. 

Preliminary cost estimations of the modified SCR process and the costs of the conventional SCR process given by J.Ando [6], demonstrate that even in case of a 90% cost reduction of the catalyst in the SCR reactor, the modified process is hardly feasible. Investment and operating cost for the ozone generation plant attributes significantly to the armual total cost of the modified process. Development of less expensive processes for flue gas composition modification with respect to the NO2 component, e.g. catalytic oxidation of NO, is an essential step towards the introduction of a commercially attractive modified SCR process. 

SCR capital cost estimates and levelized cost estimates are summarized in Table 10-17. It is important to note that there are large differences in the estimates. Early estimates are much higher than recent awards and quotes. In particular, note the significantly lower SCR capital costs provided by Wax of the Institute of Clean Air Companies (ICAC) based on 1993 market activity. More recent costs are lower due to the effects of competition, technical advances, operating experience, and fewer changes to the balance of plant than in the early estimates. Also, early SCR units were oversized as suppliers underestinuted catalyst activity. Moreover, in the U.S., the price of catalyst has dropped dramatically since the process was first introduced (Wax, 1993A). Cochran et al. (1993) also discuss some of the factors behind the reduction in SCR costs experienced in the U.S. market. 

The cost variability in Table 10-17 is due to many factors, including dale of the estimate, SCR size and type, initial and controlled NO, concentrations, fuel characteristics, catalyst life/replacement considerations, and modifications to downstream equipment. Operating cost variability depends on the following factors (Robie et al., 199IB) ... 

Environmental control is essential to meet EPA demands. It has been estimated that for a plant consuming 37 million Btu/ton of ammonia produced, environmental control will require 0.7 million Btu, and environmental costs will be 1.1 percent of the operating costs. Discharge streams that require processing to eliminate undesirable contaminants include (1) the regeneration acid and base for boiler feed-water treatment units, (2) the regeneration steam for natural gas desulfurization catalysts, (3) the low temperature shift condensate (ammonia, amines, and methanol), and (4) CO2 removal process regeneration effluents. 

In short the RCH/RP process has significant economic and environmental advantages easy and complete catalyst recovery, high catalyst activity and selectivity, simpler operation, recovery of the exothermic heat of the oxo reaction, virtual elimination of plant emissions and the avoidance of organic solvent. The costs of the RCH/RP process are estimated to be 10% lower than other oxo processes.38... 

Table V shows the salient features of several Fischer-Tropsch processes. Two of these—the powdered catalyst-oil slurry and the granular catalyst-hot gas recycle—have not been developed to a satisfactory level of operability. They are included to indicate the progress that has been made in process development. Such progress has been quite marked in increase of space-time yield (kilograms of C3+ per cubic meter of reaction space per hour) and concomitant simplification of reactor design. The increase in specific yield (grams of C3+ per cubic meter of inert-free synthesis gas) has been less striking, as only one operable process—the granular catalyst-internally cooled (by oil circulation) process—has exceeded the best specific yield of the Ruhrchemie cobalt catalyst, end-gas recycle process. The importance of a high specific yield when coal is used as raw material for synthesis-gas production is shown by the estimate that 60 to 70% of the total cost of the product is the cost of purified synthesis gas.

The cost of hydrogen was estimated by considering the capital costs, capital recovery factor, the operating expenses of the refueling station, the cost of utilities (fuel and electricity), and the cost of catalysts. The natural gas cost was assumed to be 5/ GJ on a higher heating value (HHV) basis, and the electricity cost was assumed to be 70/kWhr. The efficiency of the system (75% on a LHV basis) was used to determine the required amount of natural gas. A capacity factor of 90% for plant utilization was used. The capital recovery factor was determined as 13.1%, assuming 10% interest rate over 15 years. 

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