Sulfur inventory

The wodd s largest sulfur iaveatories are stiH ia Canada. By the end of 1994, after significant vattiag, stocks iacreased by approximately 2.2 x 10 to 7.8 X 10 t. The United States, which had 4.2 million metric tons of sulfur inventories in 1982, reduced sulfur inventories to the lowest levels in a decade during 1992, a record year for phosphate fertilizer exports. This changed during 1993—1994, when phosphate fertilizer production eased and sulfur stocks increased to 1.1 million metric tons. Sulfur inventories in Poland and West Asia have also declined slightly (33). 

The decrease in wodd sulfur inventories ended in the period 1990—1992. From 1991 to 1992, sulfur inventories remained relatively stable. However, wodd sulfur inventories in 1993 increased sharply, to an estimated 11.8 million metric tons. This increase was caused by a sharp fall in wodd demand for phosphate fertilizers, which, because of market conditions, led to a laige increase in vatting sulfur, especially in Canada. Figure 3 shows wodd sulfur inventory levels in the main producing countries or regions from 1980 through 1994. 

Sulfur inventories and pricing will be major factors which will ultimately dictate the future of SAS systems in the paving industry. To the author s knowledge no major field projects involving SAS materials are being planned for the near future. 

The temperature dependent algorithms used to predict natural sulfur emissions do not account for all of the variation in observed emissions. Other important environmental parameters may include, but are not limited to, tidal flushing, availability of sulfur, soil moisture, soil pH, mineral composition, ground cover, and solar radiation. A more accurate estimation of the national sulfur inventory will require a better understanding of the factors which influence natural emissions and the means to extrapolate any additional parameters which are determined to be important. 

For a solid sulfur product, the sulfur layer is pumped to large outside vats where it is allowed to cool. The simplest containment for this method consists of a vertical sheet metal rim which is used to hold the molten sulfur until it solidifies. Once the product is solid, the metal rim is moved upward ready to receive the next layer of molten sulfur. The large, compact dense masses of product thus formed represent one of the least expensive and best environmentally controlled forms of storage of excess sulfur inventory. For delivery, the large mass is broken up using small explosive charges or mechanical means. 

An atmospheric sulfur inventory for the whole European continent has been recently constructed by E. Meszaros et al. (1978). These authors show on the basis of the comparison of anthropogenic sulfur emission (Semb, 1978) and sulfur advection from the Atlantic that the sulfur gained by advection is small. 70-85 % of the sulfur emitted and imported is removed over the continent equally by dry (mostly in form of S02) and wet deposition. Meszaros and his associates have estimated the dry deposition of S02 by using an average European S02—S concentration calculated from data in Table 13 (3.2 /tg m-3) and a dry deposition velocity of 1cm s (Garland, 1978). The value of wet deposition was based on precipitation chemistry measurements. It follows from this quantitative calculation that Europe contributes 15-30 % of its sulfur emission to the tropospheric sulfur cycle of other areas. 

Only one-half of the sulfur inventory occurs as sulfate. The other half is present as pyrite in the sediments due to the action of sulfate-reducing bacteria living in marine muds. The reduction is made possible by organic carbon. The reaction may be written... 

On June 24, 2003, a major fire took place at the mine. After burning for a month, 300,000 tonnes of sulfur inventory had been destroyed. The massive sulfur dioxide plume spread over 1,000 km, and was tracked by satellite. The 600,000 tonne gas cloud was the largest man-made release of sulfur dioxide in history. Hussain s troops had added to the problem by flooding the mines with bitumen. 

While total block inventories in Alberta have risen since 1991, the trend is misleading. For the past few years, sour gas sulfur blocks have steadily declined. For example, the largest block inventory in Canada (outside of the oil sands) has been at Ram River, which by 2002 was over three million tonnes. Since then, the block inventory at Ram River had declined to 1.7 million tonnes by mid-2006. Between 2001 and 2005, the total sour-gas sulfur inventories have dropped by 3.5 million toimes. This decline, however, has been offset by the block inventory of Syncrude from its oil sands operations. In 2009, this inventory alone stood at more than eight million tonnes. In other words, the readily accessible sulfur inventories have steadily declined, but this decline has been outpaced by increases in remote inventories that are more difficult to market (because of logistic costs). 

Scheduling of vessels to the arrival of unit trains was nearly impossible. Large inventories of sulfur had to be kept at the port. The formed-sulfur inventory would have to be communal, since most producers were shipping through Cansulex, and later Prism, to the port. In 1970, the Solid Sulfur Train Operating and Exchange Plan established a common inventory for twenty-four sulfur producers at Vancouver. The sulfur was segregated into three piles slate, rotoform (Shell), and Ollier prill. 

Why are "oxides of nitrogen" and "oxides of sulfur" usually reported in emission inventory tables rather than the actual oxidation states ... 

Closed drain headers are normally provided for safe drainage of equipment containing severely toxic, corrosive, pollutant or high cost chemicals (e.g., phenol, sulfuric acid, monoethanolamine, sulfur dioxide, catacarb) where there is an appreciable inventory in a number of processing vessels in a plant. The header should be at least 50 mm in diameter, and should be tied into the major vessels and equipment with 25 mm minimum size connections (20 mm is considered adequate for pumps). The header may be routed to a gravity drain drum (with recovery to the process by pump or gas pressurization), or to a pumpout pump returning to the process, or in the case of sulfuric acid, to an acid blowdown drum. 

Nitroglycerin (NG) production provides a good example of the reductions in inventory that can be achieved by redesign. It is made from glycerin and a mixture of concentrated nitric and sulfuric acids. The reaction is very exothermic if the heat is not removed by cooling and stirring, an uncontrollable reaction is followed by explosive decomposition of the NG. 

PEL Pg pmol PHS PMR ppb ppm ppt REL RfD RTECS sec SCE SIC SIR SMR STEL STORET TLV TSCA TRI TRS TWA u.s. UF yr WHO wk permissible exposure limit picogram picomole Public Health Service proportionate mortality ratio parts per billion parts per million parts per trillion recommended exposure limit Reference Dose Registry of Toxic Effects of Chemical Substances second sister chromatid exchange Standard Industrial Classification Standardized incidence ratio standard mortality ratio short term exposure limit STORAGE and RETRIEVAL threshold limit value Toxic Substances Control Act Toxics Release Inventory total reduced sulfur time-weighted average United States uncertainty factor year World Health Organization week... 

U.S. Environmental Protection Agency Toxic Substances Control Act (U.S. EPA TSCA) Chemical Inventory and Test Submission Data Base, 13 694 U.S. EPA Tier 2 specification, gasoline sulfur content, 10 54. See also Environmental Protection Agency (EPA)... 

The amount of SOx produced in the regenerator can be considerable. For example, consider a 50,000-barrels-per-day unit, with a catalyst inventory of 500 tons and a catalyst circulation rate of 50,000 tons a day. The unit operates at a catalyst to oil ratio of 6. The feedstock contains 2.0% sulfur, and 7% of the sulfur in the feedstock goes to coke. For this unit, the daily SOx emissions would be 23.3 tons, expressed as SO j or 11.7 tons, expressed as elemental sulfur. 

SOx additive (50 tons) in the catalyst inventory of the unit under consideration, the additive must capture and release 0.20% sulfur, based on the weight of the additive, during each cycle. For SOx additives with capacities greater than 0.20% sulfur per cycle, smaller amounts of the additives would be required in the inventory. 

SO, additive chemistry has been described previously in literature [3]. SO, reduction additives remove SO, from the regenerator flue gas and release the sulfur as H2S in the FCC reactor. In a full bum regenerator, the amount of SO2 removed is directly proportional to the amount of additive used. Normal additive levels in the catalyst inventory range from 1-10%, with up to 20% being used in some units. Typical SO, removal rates have historically been in the 20-60% range. With the introduction of new super additives, rates in excess of 95% are commonly being achieved [4]. 

Large regenerator inventories will reduce the efficiency of an additive. Inefficient strippers increase the amount of sulfur going to the regenerator, and hence increase the SO emissions. 

Similar to other commercial commodities, sulfur is stockpiled or vatted when production exceeds demand. Inventories of elemental sulfur held by U.S. producers peaked at 5.6 million metric tons in 1977 inventories held by Canadian producers in Alberta, Canada, peaked at 20.6 million metric tons in 1978 and 1979. By 1995, annual U.S. production of sulfur in all forms had grown to 11.5 million metric tons and apparent consumption of sulfur in all forms was about 13.2 million metric tons the annual growth rate was about 3% during the 1970s and 1980s. In North America, discretionary sulfur output decreased to about 2.9 million metric tons in 1995 as overall world demand for sulfur declined. During this same period, nondiscretionary sulfur output constantly increased (21,33). 

The ability of the U. S. Frasch industry to fly-wheel domestic supply and demand in the short-run depends on its current inventories and capacity utilization. In the mid-term, mines may be opened or closed based on perceived long-term market equilibria. Longterm, however, in the absence of a significant successful exploration program, Frasch sulfur is a depleting resource. As the peakload, rather than base-load, producer its minimum price is that which will cover the costs of the incremental mine. Its actual price will represent supply-demand equilibrium in world markets. 

We anticipate that the demand/supply gap will continue to stay narrow over the next several years and that sulfur prices and profit margins will remain high. The recent supply dilemma has been alleviated partially by reduction of inventories, primarily in Western Canada and at Frasch sulfur stockpiles in the U.S. Mexico and Poland. But, since no new major sources of sulfur will be available over the near term, the world operating rate will probably continue to stay above 90% in the early 1980 s. 

In addition to the reactions that produce elemental sulfur, competing reactions also occur that produce undesirable by-products such as sodium thiosulfate. This is detrimental, because the thiosulfate remains in solution, and its concentration can generally be reduced only by bleeding off a portion of the solution inventory. This solution purge waste stream is hazardous, largely because it also contains vanadium compounds. The key to reducing the metal content of the waste stream is to reduce the rate of thiosulfate formation. 

A U. S. national biogenic sulfur emissions inventory with county spatial and monthly temporal scales has been developed using temperature dependent emission algorithms and available biomass, land use and climatic data. Emissions of dimethyl sulfide (DMS), carbonyl sulfide (COS), hydrogen sulfide (H2S), carbon disulfide (CS2), and dimethyl disulfide (DMDS) were estimated for natural sources which include water and soil surfaces, deciduous and coniferous leaf biomass, and agricultural crops. The best estimate of 16100 MT of sulfur per year was predicted with emission algorithms developed from emission rate data reported by Lamb et al. (1) and is a factor of 22 lower than an upper bound estimate based on data reported by Adams et al. 

Recent concern for the role of sulfate in acidic deposition has intensified the need for a more accurate estimation of natural sulfur emissions in the United States. The magnitude and the spatial and temporal distribution of natural sulfur emissions must be quantified in order to be useful in efforts to predict the effectiveness of various control strategies for acid deposition. The inventoiy estimates described in this paper predict monthly sulfur emissions from each county in the contiguous United States. Improvements in the methodology used to calculate this natural emissions inventory may be a useful guide in the calculation of the national emissions inventories of other naturally emitted compounds which have the potential to make significant contributions to regional air quality. 

GUENTHER ETAL VS. National Biogenic Sulfur Emissions Inventory... 

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