Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B17/00—Sulfur; Compounds thereof
  • C01B17/16—Hydrogen sulfides
  • C01B17/167—Separation
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B17/00—Sulfur; Compounds thereof
  • C01B17/16—Hydrogen sulfides
  • C01B17/168—Purification

Definitions

• the invention relates to a process for the removal of polysulfanes from gas streams formed during H 2 S synthesis.
• polysulfanes In H 2 S syntheses from hydrogen and sulfur, polysulfanes (HS n ) are generally found as by-products in the crude gas in an order of magnitude of > 400 vpm (volume per million) , and when the gas stream is compressed these tend to decompose in an uncontrolled manner into H 2 S and sulfur. This leads to undesirable sulfur deposits in the whole of the compression area, including the peripheral pipes and valves .
• the high H 2 S concentration makes the shift of the equilibrium to the left-hand side seem probable and the decomposition of the polysulfanes into hydrogen sulfide and sulfur to be a non-preferred reaction.
• the object of the invention is to provide a process for the practically complete removal of the polysulfanes, thus preventing sulfur deposits in the plant's pipes.
• the invention provides a process for the removal of polysulfanes from crude gas formed during the production of hydrogen sulfide, characterized in that the crude gas, with a content of > 80 vol., preferably > 95 vol. H 2 S and > 100 to 2000 vpm, particularly > 400 to 1500 vpm, of polysulfanes (HS n with n: 2 to 8), is passed through an optionally multi-stage washer system, brought into contact with water and/or methanol, preferably with basic aqueous and/or methanol systems, and a pure gas is obtained in which the polysulfanes are present depleted by > 50 to > 99.5%, based on the starting value.
• the quantities of polysulfanes can optionally also be more than 2000 vpm.
• Jet washers are preferably used, which, like other washers, can be operated at a pressure of 1.05 to 10 bara, preferably at 1.05 to 2 bara.
• Unpressurized operation is an alternative, however.
• aqueous and/or methanolic 0.5 to 20 wt.%, preferably 0.5 to 10 wt.%, solutions of alkali hydroxides or oxides, especially OH/KHS or NaOH/NaHS solutions, are used as washing fluid.
• the hydrogen sulfides are formed while passing the gas streams through the washing fluid.
• the suitable temperature range is generally between 0 and 150°C, especially 10 and 60°C.
• the polysulfanes are removed from the gas streams with a degree of depletion of > 50 to > 99.5%, preferably > 70 to > 99.5%, based on the starting content in the crude gas .
• the sulfur formed during the conversion of the polysulfanes goes into solution, among other things as a result of the formation of the corresponding polysulfides .
• Sulfur precipitated in solid form can optionally be discharged with the aid of suitable filtration devices.
• the washing solution circulates and is discharged as a function of the polysulfide/sulfur load.
• the washing fluid is topped up as a function of the rate of discharge and of quantities of solvent that may evaporate.
• the H 2 S-containing gas is generally after-treated with the above-mentioned solutions in a washing column or a packed bed in counter-current (counter-current washer) . Entrained droplets are separated by means of a demister system. ⁇ Any quantities of sulfane remaining in the gas stream of purified H 2 S can also be broken down in a downstream adsorber bed (activated carbon, zeolite) and the sulfur formed can be separated off.
• the polysulfane concentrations are dependent upon the reaction conditions in the HS reactor.
• H 2 S crude gas was passed through an adsorption column packed with approx. 7 1 of etched Raschig rings at 20 Nm 3 /h.
• the sulfur forming by decomposition of the polysulfanes was deposited on the surface of the packings. A degree of depletion of 25% was achieved. Service life of the adsorber bed 20 h.
• H 2 S crude gas was passed through an adsorption column packed with approx. 7 1 of Si0 2 supports (particle size 3 - 5 mm) at 20 Nm 3 /h.
• the sulfur forming by decomposition of the polysulfanes was deposited on the surface of the packings. A degree of depletion of 50% was achieved. Service life of the adsorber bed 48 h.
• H 2 S crude gas was passed first through a jet washer system operated only with water and then through an adsorption column packed with approx. 12 1 of activated carbon (particle size 5 - 6 mm) at 200 Nm 3 /h for 60 h. Before entering the adsorption column, a degree of depletion of 75% and after the column a value of > 99% was measured.
• H 2 S crude gas was passed first through a jet washer system supplied with methanol at 200 Nm 3 /h for 48 h. A degree of depletion of > 50% was achieved, based on the crude gas.
• H 2 S crude gas was passed first through a washing column operated with a methanol/triethanolamine mixture (5% triethanola ine) for 24 h at 10 Nm 3 /h.
• the sulfur forming as a result of decomposition of polysulfanes dissolved in the washing solution. A degree of depletion of 80% was • achieved.
• Example 4 H 2 S crude gas was passed through a jet washer system supplied with a methanol/NaOH mixture (5% NaOH) for 400 h at 200 Nm 3 /h. A degree of depletion of 99% was achieved.
• H 2 S crude gas was passed through a jet washer system supplied with a water/KOH mixture (12% KOH) for 200 h at 200 Nm /h. A degree of depletion of 99.5% was achieved.

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Treating Waste Gases (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)
• Gas Separation By Absorption (AREA)
• Polymers With Sulfur, Phosphorus Or Metals In The Main Chain (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)

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• 2002
  • 2002-09-26 DE DE10245164.8A patent/DE10245164B4/de not_active Expired - Fee Related
• 2003
  • 2003-08-26 AU AU2003255483A patent/AU2003255483A1/en not_active Abandoned
  • 2003-08-26 AT AT03798130T patent/ATE425121T1/de not_active IP Right Cessation
  • 2003-08-26 JP JP2004538838A patent/JP4423199B2/ja not_active Expired - Fee Related
  • 2003-08-26 BR BR0314663-4A patent/BR0314663A/pt not_active Application Discontinuation
  • 2003-08-26 WO PCT/EP2003/009432 patent/WO2004028963A1/en not_active Ceased
  • 2003-08-26 ES ES03798130T patent/ES2323060T3/es not_active Expired - Lifetime
  • 2003-08-26 US US10/529,148 patent/US7326393B2/en not_active Expired - Lifetime
  • 2003-08-26 RU RU2005112707/15A patent/RU2323874C2/ru active
  • 2003-08-26 EP EP03798130A patent/EP1542925B1/en not_active Expired - Lifetime
  • 2003-08-26 CN CNB038230240A patent/CN1292980C/zh not_active Expired - Fee Related
  • 2003-08-26 DE DE60326604T patent/DE60326604D1/de not_active Expired - Lifetime

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