CrystaSulf
Encyclopedia
CrystaSulf is the trade name for a chemical process used for removing hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

 (H2S) from natural gas
Natural gas
Natural gas is a naturally occurring gas mixture consisting primarily of methane, typically with 0–20% higher hydrocarbons . It is found associated with other hydrocarbon fuel, in coal beds, as methane clathrates, and is an important fuel source and a major feedstock for fertilizers.Most natural...

, synthesis gas and other gas streams in refineries and chemical plants. CrystaSulf uses a modified liquid-phase Claus reaction to convert the hydrogen sulfide (H2S) into elemental sulfur which is then removed from the process by filtration
Filtration
Filtration is commonly the mechanical or physical operation which is used for the separation of solids from fluids by interposing a medium through which only the fluid can pass...

. CrystaSulf is used in the energy industry
Energy industry
The energy industry is the totality of all of the industries involved in the production and sale of energy, including fuel extraction, manufacturing, refining and distribution...

 as a mid-range process to handle sulfur amounts between 0.1 and 20 tons per day. Below 0.1 tons of sulfur per day is typically managed by H2S Scavengers and applications above 20 tons per day are typically treated with the Amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...

 – Claus process
Claus process
The Claus process is the most significant gas desulfurizing process, recovering elemental sulfur from gaseous hydrogen sulfide. First patented in 1883 by the scientist Carl Friedrich Claus, the Claus process has become the industry standard....

.

Process Chemistry

In the CrystaSulf process, a heavy hydrocarbon
Hydrocarbon
In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons from which one hydrogen atom has been removed are functional groups, called hydrocarbyls....

 liquid is pumped through an absorber where the liquid contacts the gas stream that contains H2S. The H2S is absorbed from the gas stream and the clean gas stream then exits the absorber. The H2S in the liquid where it reacts with sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...

 (SO2) to form elemental sulfur and water according to the following chemical equation.

2 H2S + SO2 → 3 S + 2 H2O

The formed elemental sulfur remains dissolved in the hydrocarbon solution. Since the elemental sulfur remains dissolved, there are no solids, i.e., no slurry
Slurry
A slurry is, in general, a thick suspension of solids in a liquid.-Examples of slurries:Examples of slurries include:* Lahars* A mixture of water and cement to form concrete* A mixture of water, gelling agent, and oxidizers used as an explosive...

, in the absorber section of the process. This eliminates plugging problems that have been documented for aqueous redox processes when operated at high pressures. The SO2 that was present in the hydrocarbon solution was added prior to the solution being pumped into the absorber. The SO2 is chemically bound in the solution and readily available to react with H2S. The process is operated with an excess amount of SO2 in the solution so that there will always be sufficient amount for the liquid phase Claus reaction with H2S.

Elemental Sulfur Removal

After the dissolved elemental sulfur is formed in the hydrocarbon solution, the liquid is piped from the absorber through a flash vessel if necessary to lower the operating pressure and then through a crystallizer. The crystallizer reduces the temperature of the solution and solid sulfur is formed. The solid sulfur is removed by a filter.

After the solid sulfur is removed, the hydrocarbon solution is re-heated to approximately 150°F and the liquid is then pumped back into the absorber to continue the process of absorbing more H2S and removing it from the gas stream. The hydrocarbon solution has a low corrosion rate.

Patent information for CrystaSulf

6,416,729 B1 ; Process for removing hydrogen sulfide from gas streams which include or are supplemented with sulfur dioxide, by scrubbing with a nonaqueous sorbent; 9-Jul-2002; David W. DeBerry, Dennis A. Dalrymple

6,818,194 ; Process for removing hydrogen sulfide from gas streams which include or are supplemented with sulfur dioxide, by scrubbing with a nonaqueous sorbent; 16-Nov-2004; David W. DeBerry, Dennis A. Dalrymple, Kevin S. Fisher

5,733,516 ; Process for removal OF hydrogen sulfide from a gas stream; 31-Mar-1998; David W. DeBerry

5,738,834 ; System for removal of hydrogen sulfide from a gas stream; 14-Apr-1998; David W. DeBerry

External links


See also

  • Amine treating
  • Hydrogenation
    Hydrogenation
    Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...

  • Claus process
    Claus process
    The Claus process is the most significant gas desulfurizing process, recovering elemental sulfur from gaseous hydrogen sulfide. First patented in 1883 by the scientist Carl Friedrich Claus, the Claus process has become the industry standard....

  • Acid gas
    Acid gas
    Acid gas is natural gas or any other gas mixture which contains significant amounts of hydrogen sulfide , carbon dioxide , or similar contaminants. The terms acid gas and sour gas are often incorrectly treated as synonyms...

  • Sour gas
    Sour gas
    Sour gas is natural gas or any other gas containing significant amounts of hydrogen sulfide . Natural gas is usually considered sour if there are more than 5.7 milligrams of H2S per cubic meter of natural gas, which is equivalent to approximately 4 ppm by volume...

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
x
OK