What is hydrogen sulfide?

Hydrogen sulfide (H₂S) is a colorless gas that occurs industrially as a natural component of fossil fuels. Notorious for corrosion, toxicity, flammability, and foul odor, H₂S has been the bane of both workers and equipment since the inception of modern refining and downstream industries.

How poisonous?
How corrosive?
How explosive?
How unpleasant?

Accurate H₂S monitoring requires correction for the overlapping absorbance of other significant sulfur compounds. The OMA-300 H₂S uses robust diode array technology to continuously procure full, high-res spectra; this enables the software to differentiate between compounds and attribute absorbance where it's due. An advanced multi-component system, the OMA-300 H₂S continuously monitors dynamic concentrations of H₂S, SO₂, COS, CS₂, and mercaptans.

Click an application at left to learn more.

Common ranges: 0-1000 ppm, 0-100 ppm

The synthesis gas (syngas) produced from coal gasification can be further converted into gasoline or diesel through the Fischer-Tropsch process. The H₂S occurring naturally in coal must be removed both to meet environmental standards and protect expensive catalysts from sulfur poisoning. Online H₂S analysis at various critical sites will curb pollution, protect equipment, and validate efficiency benchmarks.

Common range: 0-300 ppm

Monitoring H₂S and SO₂ concentrations in flare gas is required to comply with the Clean Air Act Amendments (CAAA) of 1990.

In power plants and other combustion areas, the exhaust gases released to the atmosphere via flues often contain various sulfur compounds. Desulfurization units and scrubbers are used to treat the flue gas and prevent sulfur pollution. The multi-component OMA-300 H₂S continuously provides real-time levels of H₂S, SO₂, and other sulfur compounds in flue gas streams.

As with other fuels, liquefied petroleum gas (LPG) that contains H₂S will corrode equipment and cause dirty emissions. H₂S is known to cause cracking in spherical LPG storage tanks, contribute SO₂ pollution from LPG-burning engines, and destroy fuel systems that use copper or its alloys. Sulfur odor can also be a major consideration, whether you're an employee at an LPG processing plant or an end user.

Online analysis with the OMA-300 H₂S provides the caliber of LPG quality assurance that the industry requires in modern times. This fully automated system continuously monitors dynamic concentrations of H₂S, SO₂, COS, and mercaptans in propane streams. For those who have grown accustomed to regular maintenance and downtime with conventional measurement apparatuses such as lead acetate tape, the consumable-free OMA-300 H₂S will feel like a new dimension in process efficiency.

In refineries, any water that contains H₂S is considered sour. Other contaminants include ammonia, phenol, and cyanide.

The OMA-300 H₂S with the headspace sampling system is used to continuously measure dynamic H₂S and ammonia concentrations simultaneously in effluent water.

Common ranges: 0-300 ppm H₂S, 0-4% mercaptans

Mercaptans (thiols) with low molecular weight are particularly volatile, toxic, and corrosive, and are thus removed from natural gas prior to liquefaction. The typical method is caustic washing over a catalyst bed; since hydrogen sulfide interferes with this method, the H₂S must also be eliminated. Every few hours, the process switches to an alternate catalyst so that the overloaded one can be regenerated (i.e., heated and purged with carrier gas).

Optimization of mercaptan oxidation and catalyst regeneration requires multi-point, continuous monitoring of mercaptan and H₂S concentrations. The multi-component OMA-300 H₂S is commonly configured to measure dynamic ranges of mercaptans and H₂S using high-res UV absorbance spectra. This system bests traditional gas chromatography across the board; notable advantages include far less maintenance, no need for sample separation, instantaneous response, and solid state construction.

The sour feed gas stream which enters the oxidation furnace in an SRU typically contains H₂S, ammonia, water vapor, CO₂, and hydrocarbons. The furnace is used to convert H₂S and any other sulfur compounds to SO₂ and elemental sulfur. As the incoming feed gas composition varies, the amount of air needed for optimal combustion fluctuates. Without any safeguard at the front end of the SRU, the process is left vulnerable to operational upset due to H₂S fluctuation.

While a tail gas analyzer measures the H₂S:SO₂ ratio in the tail gas stream and provides feedback control, the feed forward system measures hydrogen sulfide at the beginning of the process and therefore does not have the inherent time delay of monitoring the process downstream from the reaction. The best control is achieved through use of feed forward analysis and tail gas analysis in tandem.

The OMA-300 H₂S with feed forward sample conditioning system enables fully automated air demand control. This online analyzer reacts to the real-time hydrogen sulfide levels in the sour feed gas stream for excellent response time; the rugged sample conditioning system continuously corrects for pressure and flow variations in the process.

Effective combustion control doesn't only keep your process on the right side of environmental regulations; it also protects downstream catalysts from destructive H₂S accumulation and prevents a host of downtime-intensive maintenance problems.

This system is often integrated (using a single controller and sampling system) with the MCP-200, an infrared analyzer for methane and CO₂.

Common range: 0-10 ppm ( ±0.5 ppm)

An important criterion for high-quality LNG is the absence of H₂S. In order to protect the steel in handling equipment and the copper in fuel systems, H₂S levels must be proactively reduced. At the same time, modern consumers are expressing higher expectations for clean-emitting, odor-free natural gas. Greater expectations require greater technology.

The OMA-300 H₂S is an industry-proven analytical solution for sweet gas quality assurance. Monitoring H₂S, SO₂, COS, and mercaptans simultaneously, this instrument showcases OMA-class multi-component analysis.

H₂S is known to corrode gas transport pipelines, as described above. Quality assurance at custody transfer stations helps verify gas cleanliness and protect subsequent pipelines.

Furthermore, natural gas is used for energy in homes worldwide. H₂S is a well-documented poison and should be removed from sales gas before reaching domestic burners.

Gases from different sources and with varying compositions mix together in the wellhead. Many gas wells have shut-off valves if the H₂S concentration in the mixture rises above 5 ppm, a safety measure for protecting equipment and personnel.

Analyzers for wellhead gas composition must be able to operate continuously in remote locations with limited utilities and at considerable pressures. The OMA-300 H₂S is the specialty solution for such applications, offered with a selection of purges and explosion-proof enclosures.

Common range: trace

Low ppm concentrations of H₂S in cooling water indicate heat exchanger leaks. Reliable analysis with the OMA-300 H₂S prevents wastewater pollution and equipment risks due to corrosive H₂S in recycled water.

Common ranges: 0-5000 ppm before scrubber, 0-20 ppm after scrubber

The gas produced by anaerobic digestion of organic matter can be used to generate electricity in sewage plants, provide various types of heating, and, if compressed, serve as fuel for combustion engines. Unfortunately, biogas typically contains up to 3% corrosive H₂S.

The iron drums used to store biogas are quickly destroyed by unregulated H₂S content. Downstream from storage, H₂S-rich sales gas risks costly breakdown of handling equipment and piping. Accurate H₂S monitoring with the OMA-300 H₂S equips biogas producers with long-term capacity for scrubber efficiency verification, sales gas quality assurance, and proactive equipment insurance.

Common Range: 0-300 ppm

The EPA requires measuring of H₂S concentrations in the gas harvested from landfill microorganisms. Additionally, landfill sales gas that contains significant H₂S cannot be used in power generators.

Common ranges: 0-2,000 ppm, 0-5%, 0-70%

Unmanaged H₂S contamination inevitably results in expensive catalyst corrosion.

Please see the TLG-837 Tail Gas Analyzer.

The sour feed gas stream which enters the oxidation furnace in an SRU typically contains H₂S, ammonia, water vapor, CO₂, and hydrocarbons. The furnace is used to convert H₂S and any other sulfur compounds to SO₂ and elemental sulfur. As the incoming feed gas composition varies, the amount of air needed for optimal combustion fluctuates.

The OMA-300 H₂S provides completely automated combustion control. This system continuously adjusts combustion air demand based on real-time H₂S levels in the sour feed gas stream; with wide dynamic range and ultra-fast response, the OMA-300 H₂S is designed to handle both the subtlest and most dramatic concentration fluctuations with minimal lag. Our rugged sampling systems continuously correct for pressure and flow variations in the process.

Effective combustion control doesn't only keep your process on the right side of environmental regulations; it also protects downstream catalysts from destructive H₂S accumulation and prevents a host of downtime-intensive maintenance problems.

This system is often integrated (using a single controller and sampling system) with the MCP-200, an infrared analyzer for methane and CO₂.

Amine gas treating is used to remove H₂S and CO₂ from sour gas. In the absorber unit, an amine solution absorbs H₂S and CO₂ molecules to "sweeten" the upflowing gas stream; gradually, the amine becomes "rich," or saturated, with absorbed H₂S/CO₂ and must be regenerated to restore effectiveness. Typically comprised of a stripper with a reboiler, the regenerator unit turns rich amine into "lean amine" for recycled use.

Online monitoring of lean amine composition provides real-time verification that the regenerator is working efficiently. If the amine sent back to the absorber is not sufficiently cleaned of H₂S and CO₂, it loses functionality. The OMA-300 H₂S is the popular choice for lean amine analysis; with an extremely rugged headspace sampling system, this configuration is designed for reliable accuracy on liquid streams with unpredictable backgrounds.

Amine gas treating is used to remove H₂S and CO₂ from sour gas. In the absorber unit, an amine solution absorbs H₂S and CO₂ molecules to "sweeten" the upflowing gas stream; gradually, the amine becomes "rich," or saturated, with absorbed H₂S/CO₂ and must be regenerated to restore effectiveness. Typically comprised of a stripper with a reboiler, the regenerator unit turns rich amine into "lean amine" for recycled use.

Continuous rich amine analysis is the only way to achieve optimal amine regeneration. The OMA-300 H₂S precisely identifies the event of user-specified "richness," or saturation, so that the operator knows exactly when amine solution regeneration is due. With automated feedback control, the regeneration process can be adjusted based on the measured acid gas in the rich amine; this feature has often proven an easy way to reduce energy costs.

The OMA-300 H₂S uses a rugged headspace sampling system to isolate highly accurate H₂S and CO₂ concentrations in liquid-phase amine solution. This system excels in solutions with unpredictable compositions; that excellence entails relentless accuracy and maintenance-free performance.

Common Range: 0-5000 ppm

In refineries, any water that contains H₂S is considered sour. Other contaminants include ammonia, phenol, and cyanide.

The OMA-300 H₂S with the headspace sampling system is used to continuously measure dynamic H₂S and ammonia concentrations simultaneously in effluent water.

Common ranges: 0-5% H₂S, 0-1% SO₂

Storing liquid sulfur is often handled by concrete pits in the ground with submerged steam heaters. H₂S gas is released from the sulfur stream and collects in the vapor above the pit. To keep workers safe both from toxic H₂S exposure and potential explosions, the sulfur pit is typically air-purged.

The OMA-300 H₂S is a field-trusted solution for online H₂S control in sulfur pits. Engineered for excellent dynamic range, this system tracks H₂S concentration from low ppm to hazardous % levels with seamless accuracy. Reliable measurement can be used to optimize use of expensive instrument air for purging. The OMA-300 H₂S is configured to simultaneously monitor trace-to-% levels of SO₂ alongside H₂S; since liquid sulfur fires tend to spray SO₂ fumes upward, sensitive SO₂ monitoring lets the operator know immediately when ignition occurs.

This system uses an in situ demister probe mounted directly on the pit. This proprietary design delivers the fastest response time in the industry and requires no high-maintenance sample lines or heat tracing. To learn more about the demister probe, see the sample conditioning system tab for the TLG-837.