Tessenderlo Kerley, Inc.

Tessenderio Kerley, Inc.

Mark P Clarkson

Constance Lynn Frank Lockhart

Harry Charles Kominski

Michael Massoud Hojjatie

Jeroen Van Cauwenbergh

Alexandros Dimitriadis

Nicholas S Shult

Adam T Goldsmith

Constance Lynn Lockhart

Michael Massoud Hajjatie

Mark Daniel Aspengren

Yelana (Helen) Faynshteyn

The invention relates to a process for preparing potassium thiosulfate, potassium sulfite or potassium bisulfite comprising the following steps:

Sulfur dioxide scrubbing system and process for producing potassium products

An efficient process for preparation of potassium thiosulfate (KSO) is described. Potassium hydroxide (KOH) and elemental sulfur (S) are converted to potassium polysulfide, which is subsequently oxidized. The process allows using specifically designed process conditions such as mole ratios of potassium hydroxide to sulfur, and temperature, to obtain an optimized formulation of desired polysulfide, and a specifically designed set of conditions such as temperature, pressure, rate and duration of the oxidant during the oxidation conditions, to obtain a relatively high concentration of soluble potassium thiosulfate product with high purity, with relatively low amounts of byproducts. The manufacturing process can either be a batch process or a continuous process utilizing Continuous Stirred Tank Reactors (CSTR). The CSTR process is dependent on several design parameters, including pressure, and temperature optimization to avoid product instability. The resulting potassium thiosulfate is a beneficial fertilizer with high potassium content as a 50% liquid source of potassium.

Oxidation process for producing potassium thiosulfate

The present invention relates to a system and process utilizing ammonium thio sulfate solution (ATS) as the primary liquid absorption agent that is re-circulated through an SO2 Contactor/Absorber for high efficiency contacting and absorption of sulfur dioxide, SOfrom a combustion gas stream generated by incineration of a Claus Sulfur Recovery Unit (SRU) off gas stream (often referred to as a Claus tail gas stream) and also additional SOgenerated from incineration of additional sulfur containing streams. ATS is also re-circulated through a separate H2S Contactor/Absorber for absorption of and reaction with a Sour Water Stripper (SWS) off gas stream and additional H2S-Acid Gas (A.G.) streams to produce additional concentrated ATS. The process and equipment also provides the ability to readily switch between using ATS and ABS as the primary absorbent solution for SOabsorption, depending upon the concentration of SOin the off gas feed streams.

ATS tail gas treating process for SRU and SWS off gases

The present invention relates to a system and process utilizing ammonium thiosulfate solution (ATS) as the primary liquid absorption agent that is re-circulated through an SO2 Contactor/Absorber for high efficiency contacting and absorption of sulfur dioxide, SOfrom a combustion gas stream generated by incineration of a Claus Sulfur Recovery Unit (SRU) off gas stream (often referred to as a Claus tail gas stream) and also additional SOgenerated from incineration of additional sulfur containing streams. ATS is also re-circulated through a separate H2S Contactor/Absorber for absorption of and reaction with a Sour Water Stripper (SWS) off gas stream and additional H2S-Acid Gas (A.G.) streams to produce additional concentrated ATS. The process and equipment also provides the ability to readily switch between using ATS and ABS as the primary absorbent solution for SOabsorption, depending upon the concentration of SOin the off gas feed streams.

An efficient process to produce calcium thiosulfate (CaSO) from lime, sulfur and oxygen is described. By selecting appropriate process conditions such as mole ratios of lime to sulfur, temperature and pressure of the reaction process and the oxidation conditions, including rate and duration, the concentration of byproducts in the resulting suspension can be reduced to about 2% by weight or less. The solid particulate dispersion in the suspension tends to form a slimy solid suspension that is hard to filter if not treated properly. The suspension then can be acidified and treated with a flocculent. This agglomerates the solids into a floc that filters with ease. The resulting calcium thiosulfate is a clear liquid with concentrations achievable up to 29%.

Process for preparing calcium thiosulfate solution

Ion exchange is used to make two grades of liquid fertilizer. In the first phase, ammonium thiosulfate (ATS) is contacted with a potassium-containing ion exchange resin to make the liquid fertilizer potassium thiosulfate (KTS) and an ammonium-containing resin. If operated under ambient temperatures, oxidation of any sulfites and the attendant formation of insoluble sulfates is avoided along with the associated fouling costs. The recharge line is operated in parallel to the KTS line. When the ammonium-containing resin is contacted with potassium chloride, the ammonium cations are exchanged for potassium cations and produce an ammonium chloride that can be used as a second liquid fertilizer. If desired, a concentrator can be used to remove water from each fertilizer to increase its concentration of KTS or ammonium chloride.

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Gilbert, AZ, United States of America

Mark P Clarkson