Frasch process

The Frasch process is a method to extract sulfur from underground deposits by taking advantage of the low melting point of sulfur. It is the only industrial method of recovering sulfur from elemental deposits. Most of the world's sulfur was obtained this way until the late 20th century, when sulfur recovered from petroleum and gas sources became more commonplace (see Claus process).

In the Frasch process, superheated water is pumped into the sulfur deposit; the sulfur melts and is extracted. The Frasch process is able to produce high-purity sulfur of about 99.5%. The Sulphur Institute. "An Introduction to Sulphur." , accessed 17 January 2011.

History

In 1867, miners discovered sulfur in the caprock of a salt dome in Calcasieu Parish, Louisiana, but it was beneath quicksand, which prevented mining. In 1894 the German-born American chemist, Herman Frasch (1852–1914), devised his Frasch method of sulfur removal using pipes to bypass the quicksand. This replaced the inefficient and polluting Sicilian method. The process proved successful, on December 24, 1894, when the first molten sulfur was brought to the surface. The Union Sulphur Company was incorporated in 1896 to utilize the process. However, the high cost of fuel needed to heat the water made the process uneconomic until the 1901 discovery of the Spindletop oil field in Texas provided cheap fuel oil to the region. The Frasch process began economic production at Sulphur Mines, Louisiana in 1903.

When Frasch's patent expired, the process was widely applied to similar salt-dome sulfur deposits along the Gulf Coast of the United States. The second Frasch-process mine opened in 1912 in Brazoria County, Texas. The Gulf Coast came to dominate world sulfur production in the early and middle 20th century.Handbook of Texas Online: Sulfur industry, accessed 20 February 2009. However, starting in the 1970s, byproduct sulfur recovery from oil and natural gas lowered the price of sulfur and drove many Frasch-process mines out of business. The last United States Frasch sulfur mine closed in 2000.Joyce A. Ober (2002) Materials Flow of Sulfur, US Geological Survey, Open-File Report 02-298, p.12, PDF file, retrieved 20 February 2009. A Frasch mine in Iraq closed in 2003 due to the U.S. invasion of Iraq.

The Frasch process is still used to work sulfur deposits in Mexico, Ukraine and Poland.

Process

The Frasch sulfur process works best on either salt domes or bedded evaporite deposits, where sulfur is found in permeable rock layers trapped in between impermeable layers. Bacterial alteration of anhydrite or gypsum, in the presence of hydrocarbons, produces limestone and hydrogen sulfide in the sulfur cycle. The hydrogen sulfide then oxidizes into sulfur, from percolating water, or through the action of anaerobic, sulfur-reducing bacteria

In the Frasch process, three concentric tubes are introduced into the sulfur deposit. Superheated water (165 °C, 2.5-3 MPa) is injected into the deposit via the outermost tube. Sulfur (m.p. 115 °C) melts and flows into the middle tube. Water pressure alone is unable to force the sulfur into the surface due to the molten sulfur's greater density, so hot air is introduced via the innermost tube to froth the sulfur, making it less dense, and pushing it to the surface.

The sulfur obtained can be very pure (99.7 - 99.8%). In this form, it is light yellow in color. If contaminated by organic compounds, it can be dark-colored; further purification is not economic, and usually unnecessary. Using this method, the United States produced 3.89 million tons of sulfur in 1989, and Mexico produced 1.02 million tons of sulfur in 1991.

The Frasch process can be used for deposits 50–800 meters deep. 3-38 cubic meters of superheated water are required to produce every tonne of sulfur, and the associated energy cost is significant. A working demonstration model of the Frasch process suitable for the classroom has been described.

Economic impact

+ World Production of Sulphur (1900-1929) (long tons) Year United States Italy Japan Chile Spain Total 1900 3,147 535,525 14,211 1,661 738 555,282 1901 6,867 554,203 16,287 2,037 600 597,994 1902 7,446 530,913 17,996 2,594 443 559,394 1903 35,097 545,005 22,513 3,504 1,653 607,772 1904 85,000 519,231 25,165 3,538 595 633,529 1905 220,000 559,942 24,264 3,417 600 808,223 1906 295,123 491,920 27,885 4,525 689 820,142 1907 188,878 420,229 32,803 2,859 3,555 648,324 1908 364,444 438,279 32,891 2,662 2,941 841,217 1909 273,983 428,189 36,317 4,437 3,375 746,301 1910 247,060 423,563 43,154 3,762 3,773 721,312 1911 205,066 407,620 49,481 4,380 6,476 673,023 1912 787,735 383,300 53,692 4,361 4,519 1,233,607 1913 491,080 380,209 58,509 6,542 7,381 943,721 1914 417,690 371,875 72,944 9,850 7,933 880,292 1915 520,582 352,451 71,066 9,615 9,517 963,231 1916 649,683 265,120 104,707 14,644 10,461 1,044,515 1917 1,134,412 208,501 116,224 17,787 12,681 1,489,605 1918 1,353,525 230,596 63,748 19,248 12,537 1,679,654 1919 1,190,575 222,555 49,831 18,611 11,263 1,492,835 1920 1,255,249 259,440 38,975 13,129 12,200 1,578,993 1921 1,879,150 269,547 36,013 9,517 5,170 2,199,397 1922 1,830,942 154,696 34,095 12,057 13,028 2,054,818 1923 2,036,097 252,293 36,825 11,200 8,382 2,344,797 1924 1,220,561 290,241 46,133 9,611 9,388 1,575,934 1925 1,409,262 259,428 46,962 8,929 7,859 1,732,440 1926 1,890,027 267,107 47,020 8,787 9,351 2,222,292 1927 2,111,618 300,888 60,371 12,303 10,065 2,495,245 1928 1,981,873 291,430 68,956 15,423 10,199 2,367,881 1929 2,362,389 323,000 58,718 16,000 10,000 2,770,107

List of Mines

+ Frasch Sulphur mines in the United States (1895-1966) Dome State Company From Until Total long tons Sulphur Mine La Union Dec 27, 1894 Dec 23, 1924 9,412,165 Bryan Mound Tx Freeport Nov 12, 1912 Sep 30, 1935 5,001,068 Big Hill Tx Texas Gulf Mar 19, 1919 Aug 10, 1936 12,349,597 Hoskins Mound Tx Freeport Mar 31, 1923 May 26, 1955 10,895,090 Big Creek Tx Union Mar 6, 1925 Feb 24, 1926 1,450 Palangana Tx Duval Oct 27, 1928 Mar 10, 1935 236,662 Boling Tx Union Nov 14, 1928 Aug 30, 1929 9,164 Boling Tx Texas Gulf Mar 19, 1929 >61,118,065 Long Point Tx Texas Gulf Mar 19, 1930 Oct 19, 1938 402,105 Lake Peigneur La Jefferson Lake Oct 20, 1932 Jun 7, 1936 430,811 Grand Ecaille La Freeport Dec 8, 1933 >30,885,243 Boling Tx Duval Mar 23, 1935 Apr 25, 1940 571,123 Boling Tx Baker-Williams Jun 2, 1935 Dec 18, 1935 1,435 Clemens Tx Jefferson Lake May 3, 1937 Dec 14, 1960 2,975,828 Orchard Tx Duval 1938 Orchard Tx Jefferson Lake Jun 7, 1946 >4,551,472 Moss Bluff Tx Texas Gulf Jun 24, 1948 >5,081,343 Starks Dome La Jefferson Lake Jun 15, 1951 Dec 13, 1960 840,249 Spindletop Mine Tx Texas Lake May 12, 1952 >6,310,721 Bay Ste. Elaine La Freeport Nov 19, 1952 Dec 29, 1959 1,131,204 Damon Tx Standard Sulphur Nov 11, 1953 Apr 20, 1957 139,618 Garden Island Bay La Freeport Nov 19, 1953 1991 >7,006,991 Nash Tx Freeport Feb 3, 1954 Nov 23, 1956 153,115 Chacahoula La Freeport Feb 25, 1955 Sep 28, 1962 1,199,015 Fannett Tx Texas Gulf May 6, 1958 >1,773,737 High Island Tx United States Mar 25, 1960 Feb 8, 1962 36,708 Grand Isle La Freeport Apr 17, 1960 1991 >4,466,021 Lake Pelto La Freeport Nov 26, 1960 >2,474,693 Big Hill Tx Texas Gulf Oct 8, 1965 >107,830 Sulphur Mine La Allied Chemical Sep 18, 1966 >1,447 Nash Tx Phelan Sulphur Nov 7, 1966 >622

Mexico

In 1955 Mexico became the world's second largest producer of sulfur behind the United States.

+ Native Sulfur production in Mexico (long tons) 1948-1952 (avg) 1953 1954 1955 1956 1957 Total 8,452 5,900 52,407 475,487 758,415 1,007,915 Frasch 990,122

References

Further reading

History of Sulphur (Sulphur, Louisiana)

External links (Description of Frasch process)