Hydrogen sulfide is a naturally occurring gas contained in many of the world’s crude oils. H2S has become an important topic in recent years due to the increasing demand for hydrocarbon products.
Hydrogen sulfide is a colorless gas, with an offensive odor and a sweetish taste. It is soluble in water, alcohol, oils, sulfur, and many other solvents. It has a specific gravity of 1.1895 with reference to air, and is considered a weak acid. Hydrogen sulfide can be dangerous to personnel on the surface as it is extremely toxic to human and animal life, and is extremely corrosive to most metals as it can cause cracking and destruction equipment.
A maximum of 8 h of exposure to concentrations greater than 100 ppm H2S will cause hemorrhage and death. Concentrations above 600 ppm can be fatal in 3 to 5 min. Highly stressed, high-strength steel can fail in a matter of minutes in the presence of 50 ppm H2S.
Relying solely on its odor is not recommended, since at concentrations above 100 ppm, it deadens a person’s sense of smell within a few minutes. The pure gas is heavier than air and can collect in low areas such as pit rooms and accommodation. .
The hydrogen sulfide content of fluids in the permeable formations of oil wells has a considerable impact on the economic value of the hydrocarbons produced and production operations. Typically, the sulfur content of crude oils is generally in the range 0.3–0.8 wt.%, and the hydrogen sulfide content of natural gas is in the range 0.01–0.4 wt.%, although concentrations of hydrogen sulfide in natural gas of up to 30 wt.% have been reported.
Several recent reports have claimed a systematic increase in the sulfur content of crude oils over the past 10–20 years and anticipate further significant increases in the concentration of hydrogen sulfide in both oil and natural gas.
The H2S and the H2O will react to form H2SO4 (Sulfuric Acid), a heavy oily liquid that can eat its way through a steel pipeline or storage tank that result into sharp increase of corrosion rate (2-4 times) especially that of pit corrosion.
This H2S scavenger can provide a cost-effective alternative to conventional gas/liquid sweetening processes such as amine units or solid dry bed processes to prevent hydrogen sulfide corrosion. The use of scavengers are a good economic choice. It is technically possible to use scavenger to remove high concentrations of H2S and this may be the best choice for a short-term need especially if capital cost can be minimized through continuous injection.
Our engineers can assist you in identifying and selecting the most cost-effective equipment and chemical for your facility, applying the scavenger treatments, and monitoring the results to ensure optimum performance.
Compare AS-700 and commercial H2S Scavengers:
This product is used in a significantly smaller dosage than all other regular chemicals in use today and reacts faster than other similar chemicals.Unlike other similar H2S scavengers, this product is a fast reaction chemical that react as soon as injected to the flow lines.
Features:
- Less injection rate compare to typical H2S Scavenger
- Removes H2S concentrations economically
- Eliminates safety risks
- Removes corrosion problems
- Meets natural gas sales specifications
- H2S is converted to non-hazardous compounds that are easily disposed.
- The reaction is instant and irreversible and has no effect on oil or gas quality.
Advantages of H2S Scavenger
- Eliminates safety risks
- Very low injection rate
- Maximized throughput while increasing production efficiency
- Improved injectivity by eliminating FeS from produced water, an agent known to cause plugging
- Very high temperature stability, up to 150 °C.
- No precipitation of calcium scale
- No foaming
- No emulsion
- High reactivity
- Suitable for wide pH range.
- Can be used in water phase.
- Highly effective at low pH and low temperature
- Improved operational reliability
- Conforming to the illustrated quality parameters
- Cost effective
- Available in different specifications
- Quality approved
- …
Similar Experience
CASE STUDY #1 ONSHORE CHALLENGES
- The primary goal was to reduce levels of H2S primarily for HSE and cost efficiency
- H2S scavenger that could be applied to produced fluids prior to depressurization and separation either at wellhead or downhole
- Storage Tank H2S levels 3,600 ppm (Acceptable level < 1,000 ppm)
- Fuel Gas H2S levels 2,800 ppm (Acceptable level < 500 ppm)
Results:
- 86% reduction of H2S levels in storage tank was achieved
- 64% reduction in fuel gas whilst injecting at 4,500 ppm
- During the field trials, had no adverse effects on produced water, pH and bicarbonate levels, therefore did not affect the carbonate scaling potential
- No issues in oil-in-water quality or fluid separation were observed
- Increase in production of approx. 4% crude was observed
CASE STUDY #2 OFFSHORE CHALLENGES
- Triazine scavenger residuals and reaction by-products that are returned from the gas system into produced water can cause severe scaling problems.
- With triazine calcium carbonate scale was found to build up within equipment to an unworkable level within 2 weeks and production had to be halted for the application of a dissolver.
RESULTS :
- The service provider formulated and recommended it for field trial
- It was found to reduce topside H2S levels by 83% from 32 ppm to 4 ppm with injection at 850 ppm based on total fluids
- Due to the nature of this product, the scaling tendency of the produced waters was reduced and no build up / restriction was observed
- The Scavenger treatment eliminated the requirement of the regular process shut-downs to carry out scale dissolver treatments
CASE STUDY #3 OFFSHORE
- The product is supplied subsea directly into the wellheads providing excellent reaction temperature for the scavenger
- The long tie back provides excellent reaction environment for this product with long contact time and high turbulence during the transit time to the installation
- It efficiently reduces H2S at an average of 88% to 4 ppm, which is well below the 9 ppm gas lift riser specification for this field
- This product has been found to have no detrimental effect on the oil-in-water or separation of the process
