Sulfur compounds deposition areas

Fig. 4A, B C show the activity change of mordenite catalysts as a function of copper content on catalyst for the reduction of NO with the sulfur content deposited on catalyst surface. Note that catalytic activity was defined as the ratio of the reaction rate for a deactivated catalyst to that for a fresh catalyst based on the first-order reaction kinetics a = k/k. The effect of sulfur compounds deposited on the catalysts due to the presence of S02 in the feed gas stream on SCR activity significantly depends on both the reaction temperatures and the copper content of the catalyst. For HM catalyst, the catalytic activity varies with its sulfur content depending on reaction temperatures, i.e., an exponential relationship at 250 °C and a linear relationship at 400 DC as shown in Fig.4A. It has already been investigated that the surface area of deactivated HM catalyst exponentially decreases with sulfur content at lower temperature of 250 °C, while it linearly decreases at higher temperature of 400 aC as shown in Fig. 1 A. Judging from these results between catalytic activity and surface area with their catalyst sulfur content at two different reaction temperatures, the decline of the catalytic activity for deactivated HM catalyst occurs simply due to the decrease of surface area.

Where the fuel contains sulfur compounds, sulfuric acid is ultimately formed, causing acid smutting and both hot-end (high temperature zone) and cold-end (low temperature zone) acid corrosion and fouling, and adds to the total volume of unwanted furnace area deposits. 

Poisoning of the catalyst by contaminants in the fuel/air mixture is one of the major factors affecting catalyst lifetime. Sulfur compounds in the natural gas fuel are possible catalyst poisons. Dust or other contaminants in the air ingested by the turbine could be deposited on the catalyst and mask the active sites or could react with and deactivate the catalyst. In coastal areas salt from sea air is a potential catalyst poison. The catalyst should be sufficiently resistant to these airborne contaminants so that performance is maintained for at least one year. 

Sulfur dioxide stimulates oxidation. It is the major driving force for corrosion in metropolitan areas. Most of the sulfur acquired by surface is not in the form of gas but as dry deposition. In an urban atmosphere, SO is abundantly found in aerosol particles. Large particles containing ammonia are also found. H2S, SO2 and COS in all these participate directly in the corrosion process. The sulfur compound, COS, hydrolyzes to form H2S and it may form CU2S if the quantity of COS is abundant on the other hand, SO2 may hydrolyze to form a bisulfate ion. 

In accordance with the production plans (Odisharia et al 1994), the increase of emission rate for nitrogen oxides (NO ) in the area of Bovanenkovo gas exploration in Yamal peninsula will be during 2000-2015 (Figure 7). Emission of sulfur oxide will be practically permanent and will amount to about 470,000 tons per year. These data indicate also the growth of deposition rate for acid forming and eutrophication compounds in comparison with the present period (Table 1). 

In the plains, Cambisols place the most drainage areas. These soils occupy the hilly plains and low mountain belts up to the 500-700 m elevation, where they coincide with the Broadleaf and Coniferous-Broadleaf Forest ecosystem types. In the most continental parts the oak forests are dominant. For instance, at the slopes of the Sikhote-Alin range Cedar-Broadleaf Forest and in Korean peninsula, the Oak-Maple Forest ecosystems are predominant. In Japan Beech Forest ecosystems are the most abundant. Heavy precipitation rates during wet season (up to 1000-1200 mm with P PE equal to 1) favor the increasing base saturation in the Luvic Cambisols. These ecosystems are characterized by a moderate rate of organic matter turnover with mean values of Cb equal to 2.5 C, is 0.67 and Cbr is 1.7. Such moderate rates are favorable to soil acidification with deposition input of sulfur and nitrogen acid forming compounds (NIES, 1996, Bashkin and Park, 1998). This process can be especially enhanced in... 

The general concept of the atmospheric transport and deposition computational method is that the concentration of any substance determined on the basis of its emissions, is subsequently transported by (averaged) wind flow and dispersed over the impacted area due to atmospheric turbulence. Basically, the rate of substance removal from the atmosphere by wet and dry deposition and photochemical degradation is described by general model algorithms. The transport and dispersion of HM in the atmosphere are assumed to be similar to those for other air pollutants, for instance, such as SO2 and smog compounds (Pacina et al, 1993 de Leeuw, 1994, EMEP/MSC-E, 1996 Dutchak et al, 1998). Based on such an approach, the computational results of sulfur deposition over the area of interest obtained by other authors might be particularly used for the estimation of HM depositions. 

The per cent of the coals sulfur that is lost to the system has been included in Table IV. This loss has been attributed to deposition on the reactor walls, dissolution in the liquid product, and evolution from the system as a gaseous compound. No attempt has been made to pursue these latter areas although the reactor scale contains sulfur as a sulfide. 

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