Sulfur production, sources

Figure 7 World sulfur production (source http //pubs.usgs.gov/of/of01-197/html/app5.htm).

By 1987, sulfur trioxide reagent use in the United States exceeded that of oleum for sulfonation. Sulfur trioxide source is divided between Hquid SO and in situ sulfur burning. The latter is integrated into sulfonation production faciUties. 

Sources of sulfur are called voluntary if sulfur is considered to be the principal, and often the only, product. Sulfur has also been recovered as a by-product from various process operations. Such sulfur is termed involuntary sulfur and accounts for the largest portion of world sulfur production (see Sulfur REMOVAL AND RECOVERY). 

Pyrite is the most abundant of the metal sulfides. Eor many years, until the Erasch process was developed, pyrite was the main source of sulfur and, for much of the first half of the twentieth century, comprised over 50% of world sulfur production. Pyrite reserves are distributed throughout the world and known deposits have been mined in about 30 countries. Possibly the largest pyrite reserves in the world are located in southern Spain, Portugal, and the CIS. Large deposits are also in Canada, Cypms, Einland, Italy, Japan, Norway, South Africa, Sweden, Turkey, the United States, and Yugoslavia. However, the three main regional producers of pyrites continue to be Western Europe Eastern Europe, including the CIS and China. 

Figure 2.7 U.S. production of sulfur and sulfuric acid. Source Lowenheim and Moran, Chemical and Engineering News, Chemical Economics Handbook)...

Volcanic and Other Surface Deposits. Sulfur is recovered from volcanic and other surface deposits by a number of different processes, including distillation, flotation, autoclaving, filtration, solvent extraction, or a combination of several of these processes. The Japanese sulfur deposits are reached by tunnel, and mining is done by the room-and-pillar, chamber-and-pillar with filling, and cut-and-fill systems. Sulfur was historically extracted from the ore by a distillation process performed in rows of cast-iron pots, each containing about 180 kg of ore. Each row of pots is connected to a condensation chamber outside the furnace. A short length of pipe connects each pot with a condenser. Brick flues connect combustion gases under the pots. Sulfur vapor flows from the pots to the condensation chamber where the liquid sulfur is collected. The Japanese ore contains 25—35 wt % sulfur. This method has been superseded by other sources of sulfur production. 

Energy demand, the implementation of sulfur oxide pollution controls, and the future commercialization of coal gasification and liquefaction have increased the potential for the development of considerable supplies of sulfur and sulfuric acid as a result of abatement, desulfurization and conversion processes. Lesser potential sources include shale oil, domestic tar sands and heavy oil, and unconventional sources of natural gas. Current supply sources of saleable sulfur values include refineries, sour natural gas processing and smelting operations. To this, Frasch sulfur production must be added. 

Since the 1950 s there has been a remarkable growth in sulfur production from the hydrogen sulfide of natural and refinery gases. Once a minor source of world brimstone, sour gas now makes a very significant contribution to world sulfur production. 

The four major sections of the review cover developments in new sour gas Sources, improvements in Production techniques associated with the separation and conversion of H2S to elemental sulfur, aspects of the Environmental impact and its minimization and, finally, new developments in the forming and handling of the sulfur Product itself. 

The intervening years to 1981 have seen several world market sulfur demand cycles which have effected the rate of acceptance of these new sulfur sources but slowly the recovered sulfur product has taken its place alongside other world sulfur sources such as Frasch mined and pyrites. In very recent times there have even been moves to re-open very sour gas wells as sulfur wells as world demand for this key commodity has grown and prices have crossed 100/tonne FOB the plant gate. 

Recovered sulfur sources in Middle East countries have also been developed recently. Most important of these is the Saudi Arabian gas recovery program at Berri, Shedgum and Uthmaniyah which will initially add some 4,000 tons/d to recovered sulfur production. This additional 1.5 million tons/annum of recovered sulfur will further enhance the growing dominance of recovered sulfur in the total world market picture. 

In 1979 sulfur obtained as a by-product from petroleum refining accounted for 19.7 percent of total sulfur produced in the U.S. The requirement to desulfurize residual fuels or alternatively to refine them to finished transportation fuels will result in a substantial increase in sulfur produced at refineries even if medium sweet crudes continue to be the primary refinery feedstock. However, most experts predict that crudes will become sourer in the future. The contribution from natural gas is an additional uncertainty. Conventional wisdom predicts that natural gas demand will maintain current levels or possibly decline over the next 20 years. The combination of these factors may increase conventional by-product sulfur from petroleum and natural gas by a factor of three or more by the year 2000. This would bring its sulfur contribution up to approximately 12 million tons by 2000, the same as that predicted by the MITRE estimate for synthetic fuels sulfur production. Thus, a possible total contribution of 60 percent of projected sulfur demand could be met by the combination of these by-product sources of sulfur. 

Table I provides a summary of the outlook for world sulfur supply over the coming decade. This table shows the combined totals of all sources and forms of sulfur elemental and non-elemental as well as discretionary and non-discretionary, including the use of pyrites. As the bottom line in the table shows, we anticipate that world sulfur supplies will grow at a faster rate over the coming 5-10 years than they have in the recent past. Of particular interest is the considerably expanded sulfur production outlook that we forsee for the U.S. and Mexico over the coming decade, the basis for which will be discussed later in this paper.

During the late 1960 s and 1970 s free world production and consumption of sulfur have changed significantly, especially in North America. Because of the very nature of sulfur sources and uses, the future holds the potential for some major shifts in the traditional patterns. In the spring of 1981 a Sulfur Symposium held as part of the 181st Annual ACS Meeting in Atlanta attempted to review the potential for new sulfur production and utilization (traditional production and consumption technology was not addressed), and this volume is based on the papers presented. 

On the supply side, sulfur production is now controlled more by the demand for energy through the desulfurization of fuels than by the demand for sulfur per se, and this tendency is increasing. In 1965 involuntary byproduct recovered sulfur amounted to less than 20% of total elemental sulfur production in the United States and Canada, but by 1980 over 60% of all elemental sulfur resulted from refinery and natural gas processing operations. Many future hydrocarbon energy sources (coal, deep gas, heavy oil, shale, etc.) contain considerably more sulfur compared with conventional hydrocarbon fuels, and thus their exploitation will add to the ever increasing supply of by-product sulfur. 

There have been a number of studies of biogenic emissions of sulfur gases other than H2S reported in the literature. Most of these have been concerned with high productivity sources, such as salt marshes and tidal areas and are summarized in Table II. 

The United States is now the major sulfur producer, accounting for 20% of world production. The most important sources in the US are from Louisiana and Texas, and other major producers are Japan, Canada, China, Russia, and Mexico. World sulfur production (and apparent consumption) peaked at nearly 60 Mt in 1989 and declined by almost 14% to 52.8 Mt in 1993 (Figure 7). There was a partial recovery from this time and future growth is expected. 

Fumaroles represent a gentler and more continuous source of sulfur. The sources can be dispersed and quite small, so the total emissions from this source are not easy to estimate. Some of them are dominated by H2S. The sulfur gases, SO2, H2S, Sg, have been found in a range of fumaroles (Montegrossi et al., 2001). Although present Sg remains a minor component several orders of magnitude below SO2 and H2S. The production of sulfuric acid through aerial oxidation of sulfur(IV) is the most familiar process but it can readily be produced by disproportionation in fumarolic systems (Kusakabe et al, 2000) ... 

If hydrogen sulfide is not conveniently available from local process sources it may be produced on site by reducing a part of the sulfur product of the process with methane (Eq. 3.31). 

TABLE 9.2 Sources of Sulfur Production for Major Producers in 2000, as Percentages of the Totai"... 

Extensive dust removal facilities are required to clean up the sulfur dioxide stream from these sources, which adds substantially to the capital cost of the plant and offsets the raw material cost advantage obtained from these sulfur sources. Sometimes, hydrogen sulfide is simply burned to produce sulfur dioxide when the source of the hydrogen sulfide is near a producing sulfuric acid plant. If this method is used then the need for elemental sulfur production by the Claus process is bypassed. 

Sulfur compounds in the atmosphere are provided by the decomposition of organic matter, combustion of fossil fuels, production of sea salt particles and volcanic activity. We can rather well quantify the strength of these sources, except the intensity of biological sulfur production. 

On the basis of the foregoing discussion and further considerations the schematic atmospheric sulfur budget represented in Fig. 19 is proposed. The terms in the cycle were determined as follows. We accepted the figures of Friend (1973)for the strength of anthropogenic sources and for the sulfur production rate by volcanos (65 x 1061 yr 1 and 2 x 1061 yr respectively). On the other hand, we assumed, in accordance... 

Traditionally, sulfur has been produced using the Frasch process, in which superheated water (440 K under pressure) is used to melt the sulfur, and compressed air then forces it to the surface. For environmental reasons, the Frasch process is in decline and many operations have been closed. Canada and the US are the largest producers of sulfur in the world, and Figure 15.2 shows the dramatic changes in methods of sulfur production in the US over the period from 1970 to 2001. The trend is being followed worldwide, and sulfur recovery from crude petroleum refining and natural gas production is now of greatest importance. In natural gas, the source of sulfur is H2S which occurs in concentrations of up to 30%. Sulfur is recovered by reaction... 

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