Hydrogen Sulfide (H2S)
Hydrogen Sulfide (H2S) is a colorless, flammable and extremely dangerous gas. It is found in many refinery streams such as crude oil, asphalt, residual fuel, mid distillate, gasoline and blend components. As well as natural gas, propane and LPG. It is heavier than air and can travel along the ground.
Protection Against H2S Exposure
In concentration as low as .0054 ppm the stream containing the gas smells like rotten eggs. In higher concentrations over 10 ppm, it desensitizes the olfactory nerves. A level of H2S gas at or above 100 ppm is
Immediately Dangerous to Life and Health (IDLH). The use of personal H2S monitors is mandatory as well as fixed H2S sensors located around the plant.
The removal of CO2 commonly occurs with the removal of H2S in the refinery streams. This is because certain amines absorb both CO2 and H2S.
An Amine unit typically contains a counter current absorber where the gas stream containing H2S and CO2 comes in contact with the liquid amine. The rich amine solution is sent to a regenerator or desorption column where the H2S and CO2 is stripped and the amine recycled.
The stripped H2S gas from the Amine unit will be processed in another unit called a Claus plant. In the Claus plant 1/3 of the H2S reacts with with O2 and forms SO2. The SO2 reacts with the balance or 2/3 of the H2S to form molten sulfur and water vapor.
The key to selecting the proper treatment scheme is dependent upon the concentration not only of H2S, but also of carbon dioxide and ammonia. Let COSTELLO help you with determining the proper H2S treatment scheme for your mini refinery processes.