Decomposition process costs

The energy requirement per mole of hydrogen produced (37.8 kJ/mol H2) is somewhat less than for the SR process. Due to a relatively low endothermicity of the process, less than 10% of the heat of methane combustion is needed to drive the process. In addition to hydrogen as a major product, the process produces a very important byproduct clean carbon. The process does not include the WGS reaction and energy-intensive gas separation stages. A preliminary process design for a continuous methane decomposition process and its economics has been developed.7 The techno-economic assessment showed that the cost of hydrogen produced by TD of NG ( 58/1000 m3 H2, with carbon credit), was somewhat lower than that for the SR process ( 67/1000 m3 H2).7... 

Thermal DeNOx Process Costs and Requirements in Application to Boilers and Furnaces With a modest 1.5 to 1 excess of NH3 over NO t he Thermal DeNOx reaction is capable of reducing NOx to levels which in an ideal case would be very low. For NFf at 290/ ton this corresponds to a cost of 161/ton of NOx removed. In some applications hydrogen is not needed but in others it is. For some of the latter applications it is readily available and inexpensive. In others hydrogen must be generated by NHg decomposition. For a situation in which H2 at 2/1 ratio to NF is needed, the NFf thus used would cost 214/ton of NOx removed. 

Against this rather bleak economic backdrop, the commercial potential for the decomposition process appears quite attractive. Obviously, since a single optimized process has yet to be identified, the detailed economics of the decomposition technique are impossible to estimate. Nevertheless, some instructive cost comparisons can be made. 

Increased capital cost penalty to decomposition process (25% over Claus) ( 8.00)... 

However, in spite of this conservative approach, it is clear from Table I that the decomposition process offers considerably more profit potential than the conventional Claus process. Recalling that the totals in Table I represent only the comparative profitability, comparison of the actual profit generated by each process favors the decomposition process more strongly. For example, the total capital and operating costs for a medium sized (150 - 200 tonne/day)... 

Claus plant (including tail gas treatment) are of the order of 32/tonne exclusive of steam credit. Subtracting these costs from the totals in Table I, the overall net revenue from the Claus system would be 21.75/tonne of sulphur produced whereas that from the decomposition process would be 50.50 /tonne - a 230% difference. Even in the unlikely event that the total capital and operating costs for the decomposition process exceed those of the Claus system by 100%, the two processes are still approximately competitive. 

In comparison to the well known results achieved in plug flow systems, the flame regime causes a number of differences corrosion and plugging are markedly alleviated and acceptable decomposition efficiencies aren t achieved except in special cases, whereby the process cost increases to a considerable extent. Amongst the several components contributing to the overall process cost, the required fuel mass fraction of the waste water (more exactly the overall heating value of the mixture of water and fuel) would appear to be the most important one. 

One of other conventional processes for H2O decomposition is photoelectrochemical. In this method, H2O is broken down into H2 and O2 by electrolysis, but the electrical energy is obtained by a photoelectrochemical cell (PEC) process. A photoelectrochemical H2O decomposition process is a zero emission process and uses free solar energy or ultraviolet (UV) light (Alenzi et al., 2010 Currao, 2007 Nowotny, Bak, Nowotny, Sheppard, 2007). Many studies have been presented for finding the best material candidate for the photoelectrochemical process discovered by Fujishima and Honda (1972) as a first approach. The main criteria for these materials are low cost. 

In conclusion, presenting the comprehensive analysis of NO decomposition in MR systems needs more research. On the other hand, to prevent the high cost of experimental studies, modeling technique can be suggested as a suitable procedure. However, to our best knowledge, there is no presentable modeling study about NOx decomposition process in the MR set-up. 

Conventional triorganophosphite ligands, such as triphenylphosphite, form highly active hydroformylation catalysts (95—99) however, they suffer from poor durabiUty because of decomposition. Diorganophosphite-modified rhodium catalysts (94,100,101), have overcome this stabiUty deficiency and provide a low pressure, rhodium catalyzed process for the hydroformylation of low reactivity olefins, thus making lower cost amyl alcohols from butenes readily accessible. The new diorganophosphite-modified rhodium catalysts increase hydroformylation rates by more than 100 times and provide selectivities not available with standard phosphine catalysts. For example, hydroformylation of 2-butene with l,l -biphenyl-2,2 -diyl... 

Relatively high (typically 980—1200°C) temperatures are required to decompose spent acids at reasonable burner retention times. Temperatures depend on the type of spent acid. A wide variety of spent acids can be processed in this way, but costs escalate rapidly when the sulfuric acid concentration in spent acid (impurity-free basis) falls below about 75%. A few relatively uncontaminated spent acids can be reused without decomposition by evaporating the excess water in concentrators, or by mixing in fresh sulfuric acid of high concentration. Weak spent acids are frequently concentrated by evaporation prior to decomposition. 

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