Testing and Treating H2S and Mercaptans in Crude Oil 

We recently attended a conference in Salt Lake City, where we discussed various testing methods for H2S and mercaptans. Given the significant interest in this topic, we want to provide an overview for those who could not attend. Crude oil, a crucial resource in the energy industry, often contains unwanted contaminants such as Hydrogen Sulfide (H2S) and Mercaptans. These compounds not only impact the oil’s quality but also pose substantial health and safety risks. In this blog, we will delve into the testing and treatment methods typically used for these compounds. 

A Brief Overview of H2S & Mercaptans 

Hydrogen Sulfide (H2S): 

H2S is a toxic and pungent gas found in both the formation and post-production phases of crude oil. It is present in crude oil, natural gas, and water, earning it the nickname “sour gas.” H2S is soluble in water and behaves like a weak acid, making it corrosive. 

Mercaptans (RSH): 

Mercaptans are organic molecules with a structure resembling alcohol but with a sulfur atom chained to hydrocarbons, known as thiols. There are many mercaptan species, and they are notorious for their unpleasant odor. The human nose can detect mercaptans at concentrations as low as 10 parts per billion (ppb). 

Testing Procedures 

Testing for H2S and Mercaptans is a crucial step in ensuring the quality and safety of crude oil. However, not all testing methods are created equal, and the choice of method often depends on the commercial contract. Some common testing methods include: 

Vapor Testing:  

• ASTM 5705 modified: A test that yields results in H2S concentration (ppm/v). It has been modified to test crude oil since it was originally designed for fuel oil testing. 

Liquid Testing: 

• ASTM D7621: A standard method for determining H2S in fuel oils by rapid liquid phase extraction. 
• UOP 163: A titration that measures H2S (ppm/w) and mercaptan (ppm/w) concentrations. 
• ASTM D5623: A GC method that provides H2S (ppm/w) and mercaptan speciation (ppm/w) data. 
• ASTM D130-9/D1838-16: A subjective copper strip test for specific sulfur contaminants. 

Results obtained through these tests are vital for H2S scavenging, ensuring safety, and adhering to contract specifications. Historically, there has been a lack of correlation between different test methods, emphasizing the importance of using a consistent method throughout the process. In the United States, UOP 163 and ASTM 5705 are commonly used for crude oil quality contracts. 

Challenges with Testing Methods 

• ASTM 5705 modifications may be necessary to adapt to crude oil testing conditions, and there is no standardized temperature for testing in practice. 
• Reading stain tubes can be challenging. Moisture in the air and other contaminants in the raw crude oil may negate the accuracy of the tube. 
• UOP 163 may suffer from interference by chemical contaminants and variations in technicians’ interpretations of titration curves. 

Scavengers for H2S and Mercaptans 

To address the presence of H2S and Mercaptans in crude oil, various scavenging methods are employed. These include: 

1. Typical Amines:

• Monoethanolamine (MEA) 
• Diethanolamine (DEA) 
• N-methyldiethanolamine (MDEA) 
• Diglycolamine (DGA) 

2. Non-Regenerative H2S Scavengers:

• Solid, basic metallic compounds 
• Oxidizing chemicals 
• Aldehydes, including Formaldehydes 
• Reaction products (may include triazines) 
• Metal carboxylates/chelates 
• Other amine-based solutions 

Each of these chemical solutions has its advantages and disadvantages, making it necessary to evaluate them on a case-by-case basis. 

Alternatives to Treat H2S 

In addition to scavenging methods, nitrogen stripping is an alternative approach to treat H2S. This method involves bubbling nitrogen through a column, which attracts H2S, allowing lighter-end volumes to escape and be transported to a flare. However, this process comes with its own set of considerations, including the need for a compressor, a nitrogen membrane generation unit, stripping tower kit, and a tie-in to the flare line. Moreover, the loss of hydrocarbons at the flare may raise environmental, social, and governance (ESG) concerns. 

Why It Matters 

Understanding and effectively addressing H2S and Mercaptans in crude oil is essential for various reasons: 

• Prolonging Asset Life: Proper treatment ensures that your assets last longer, maximizing their value. 
• Expanding Markets: High-quality crude with low H2S and Mercaptan content opens doors to more markets. 
• Building Optionality: The ability to adapt to different market conditions leads to better netback prices. 
• Ensuring Personnel Safety: Protecting the health and safety of workers is of utmost importance. 
• Asset Integrity: Treating H2S and Mercaptans preserves the integrity of equipment and facilities. 

 Managing H2S and Mercaptans in crude oil is a critical aspect of the industry. By understanding the characteristics of these compounds, employing appropriate testing methods, choosing effective scavengers, and considering alternative treatments, companies can ensure safer operations and better financial outcomes. Ultimately, the equation for success in the industry is the combination of the highest quality and merchantability, resulting in the highest netback prices. 

Final Thoughts  

Understanding and complying to the commercial contract is paramount. These commercial contracts will stipulate which method is required to meet specifications, so when in doubt, have the operations team speak to the crude quality or commercial teams to understand the exact parameters to ensure the quality of the crude is being met for final delivery. 

The Science of H2S Removal: Our Oilfield Chemical Solutions

 

 

 

 

 

 

 

 

 

As one of the leading H2S scavenger manufacturers and oilfield chemical suppliers in the industry, Q2 Technologies is committed to delivering high-quality H2S removal solutions to its clients. We understand the importance of removing H2S from natural gas and crude oil, as it is a toxic and corrosive gas that can cause serious damage to pipelines, equipment, and the environment. In this blog post, we will discuss the science of H2S removal and how our oilfield chemical solutions can help. 

H2S Scavengers: How they work 

H2S scavenger technologies are used to remove hydrogen sulfide (H2S) from natural gas and crude oil streams. There are various chemistries used for H2S scavenging, including nitrite-based, triazine-based, iron sponge, and caustic-based methods. 

Nitrite-based scavengers work by oxidizing H2S to elemental sulfur in the presence of oxygen. These scavengers can also provide corrosion inhibition, making them a popular choice in certain applications. 

Triazine-based scavengers react with H2S to form stable, non-toxic compounds that can be easily separated from the treated gas or liquid. They are often used in natural gas processing and refining. 

Iron sponge is another common H2S scavenger. It works by using iron oxide to react with and remove H2S from gas streams. 

Caustic-based scavengers (such as sodium hydroxide) react with H2S to form sodium sulfide, which can then be further treated or disposed of. They are commonly used in refineries and other industrial processes. 

Each H2S scavenger has its advantages and disadvantages, and the choice of scavenger depends on several factors such as the composition of the production stream, operating conditions, and environmental regulations. However, with careful selection and application, H2S scavengers can effectively reduce the risks associated with H2S gas in the oil and gas industry. 

H2S Removal Solutions from Q2 Technologies 

At Q2 Technologies, we offer a range of H2S removal solutions to meet the needs of our clients from liquid non-triazine products, iron-based scavengers, to more traditional triazine based scavengers, all designed at removing H2S from crude oil and natural gas. Specifically for crude oil and liquid hydrocarbons, Pro3® is a non-triazine scavenger that offers several advantages over other H2S scavengers, including: 

1. High H2S removal efficiency: Pro3® is highly effective at removing H2S from crude oil streams, even at low concentrations. This is due to its unique chemical composition, which enables it to react with H2S and convert it into sulfate byproducts which drop out into the BS&W. 
2. Long-lasting protection: Pro3® provides long-lasting protection against H2S, which reduces the need for frequent scavenger injections. This can help to reduce costs and increase operational efficiency. 
3. Environmentally friendly: Pro3® is a non-triazine-based H2S scavenger, which means it does not contain triazine or amine compounds that can be harmful to the environment. 
4. Compatible with other chemicals: Pro3® is compatible with other chemicals commonly used in oil and gas operations, including corrosion inhibitors and demulsifiers. This makes it easier to integrate into existing operations. 

Overall, Pro3® offers a high-quality, effective, and environmentally friendly solution for H2S removal in the oil and gas industry. Its unique chemical properties and benefits make it a preferred choice for many Producers and Midstream companies looking to improve their H2S removal processes. 

In addition to Pro3®suite of products, Q2 Technologies offers several other products from this chemical line including  ProM®  and Pro3®HT , all H2S scavengers for the removal of hydrogen sulfide from  crude oil and liquid hydrocarbon streams. ProM® is an oil dispersible  option that is ideal for combating against certain species of mercaptans (a similar sulfur-based compound). Pro3®HT is a specialized product designed for high-temperature applications, with stability and effectiveness up to 150°C (302°F).  

For sour natural gas applications, we offer a range from traditional triazine-based products to non-triazine products in both liquid and dry media applications.  

1. Triazine based scavengers, if properly managed, can be a standard approach to treating H2S. We also provide a vast range of field strength concentrations as well as several additives that can be used for greater effectiveness or for compatibility concerns. 
2. We also have a non-triazine/non-amine alternative to MEA triazine: Pro3®GT & Pro3®GT+ are specially formulated to have the same outcome as triazine. However, GT & GT+’s reactions are not subject to the same side effects one experiences when overtreatment occurs with triazine, such as scale or buildup of particulates. Further, Pro3®GT & Pro3®GT+ has more kinetic prowess than triazine, typically using 20% less overall product when compared to triazine. 
3. Lastly, Pro3®Nano is our innovative dry media that can effectively target H2S in sour natural gas streams that tend to have significant production swings or experience massive ranges in H2S. This product can handle any environment and will provide a sweetened gas stream consistently. With a regenerative aspect, this system is a great change to traditional liquid systems, where the product can be re-energized in system. 

Conclusion 

The importance of removing H2S from natural gas and crude oil cannot be overemphasized, as it is a toxic and corrosive gas that can cause serious damage to pipelines, equipment, and the environment. Q2 Technologies‘ Pro3® H2S scavenger, along with its other products, offers a unique and effective solution for H2S removal, with advantages such as high H2S removal efficiency, reduced iron sulfide formation, long-lasting protection, and environmental sustainability. With a range of options available, Q2 Technologies offers tailored H2S removal solutions that meet the specific needs of its clients, making it an ideal partner for any oil and gas operation. 

If you are interested in learning more about our H2S removal solutions, please contact us. Our team of experts is always ready to answer any of your questions. 

Hydrogen Sulfide (H2S) is a highly corrosive chemical found in Crude Oil, Natural Gas, Production Water, and Formation Water. The presence of H2S in Crude Oil and other volumes plays a significant health risk for those close to or exposed to this noxious substance. Because of its toxicity, if inhaled it can lead to numerous health problems and, in some cases, even death. Workers in the oil and gas Exploration, Production, Midstream,  and Refining Industries may be exposed to this hazardous substance so they must follow a set of safety measures that are outlined below. Please consider the following as a starting point, always consult your company’s EH&S or manager for safety specific requirements.

 

Why is H2S so dangerous?

Health

• The health consequences of hydrogen sulfide depend on how much and how long the worker breathes it in. Exposures to concentrations of 100 ppm or more are harmful to human health. However, even at low doses, significant impacts are observed. The effects range from moderate, such as headaches or eye discomfort, to extremely dangerous, such as permanent loss of smell and taste to unconsciousness and death. 

Damage

• In oil and gas applications, sour gas and sour crude (which contains H2S) can react with air and moisture to produce sulfuric acid, which can corrode metals. The durability and impact strength of facility equipment, particularly the inside surfaces of different components, are diminished, eventually resulting in premature failure.

 

Safety Equipment

 

H2S Monitor

• Always make sure to carry an electronic meter that detects hydrogen sulfide gas. And clip the monitor near your face, on the lapel of your shirt for example.  Always “bump test” by clicking the test button on the monitor prior to entering any job site to ensure the alarm on the monitor is loud –  there may be large decibel producing equipment creating loud noises, your monitor should be louder so you can hear it.
• Do not rely on your sense of smell to detect the presence of hydrogen sulfide or to alert you of dangerous amounts. At low quantities in air, hydrogen sulfide has a “rotten egg” smell. However, after a while, you lose your capacity to detect the gas even if it is still present (olfactory fatigue). In large quantities, this loss of smell can occur extremely quickly, and the ability to detect the gas can be gone instantly (olfactory paralysis).

 

Protective personal equipment

 

• Wear respiratory and other personal protective equipment.
• Make sure you have been properly mask fitted to make sure you will be protected from hazardous vapors.
• If measures fail to lower H2S levels below the allowed exposure limit, respiratory protection must be used as well as additional personal protective equipment (PPE) such as eye protection and perhaps fire-resistant clothing. 

 

Safety Measures

 

Imagine your hydrogen sulfide sensor has gone off, indicating the presence of H2S in your work environment. Now, what do you do?

 

1. Put On Your Gear:

Put on your gas mask if you have one handy and aren’t already wearing one. Pull your straps down firmly and breathe. While you evacuate the area, your mask will keep you safe. 

The requirements for carrying a mask differ based on the setting, so if you don’t have one, don’t worry, just go on to the next stage.

2. Get Upwind: 

• If you’re working in an area with the possibility of H2S release, there should be flags or windsocks on the work site to show you which direction the wind is blowing. Head in the opposite direction immediately. If you can’t see the windsock, toss some dirt or leaves into the air, or look at the trees. 
• The wind can blow and concentrate the H2S into valleys or stands of trees, so the direction you go is essential. If you see a designated gathering area, or “muster site” downwind, go there. 
• This is the easiest and most effective way to avoid H2S inhalation or poisoning.
• Lastly, if your work plan makes it difficult to evacuate an area, consider revising your work plan with your team before starting work in the first place.

H2S Removal

H2S Scavengers should be employed by crude oil companies to benefit from less fouling, corrosion, and property damage, significant reduction of health risks, and a potential increase in the value of production barrels.  

 

In conclusion, anyone who has the possibility of being exposed to H2S must be ready with the recommended safety equipment and the know-how for whenever the H2S monitor goes off.

Always carry:

• H2S monitor
• Properly fitting PPE

If the monitor goes off, remember to:

• Put on your gear
• Get upwind

 

Q2 Technologies manufactures specialty H2S Scavenger Chemistry products that remove H2S from millions of barrels of oil every month. For more information, contact us! 

 

Sources:

https://www.osha.gov/hydrogen-sulfide

https://www.draeger.com/library/content/h2s-ebook-enus.pdf

https://www.fldata.com/hydrogen-sulfide-oil-gas-industry

https://www.gdscorp.com/blog/hydrogen-sulfide/the-four-steps-to-take-in-a-hydrogen-sulfide-h2s-

emergency/#:~:text=Get%20Upwind&text=The%20wind%20can%20blow%20and,avoid%20H2S%20inhalation%20or%20poisoning.

 

When it comes to treating Hydrogen Sulfide (H2S) in Crude Oil and liquid hydrocarbons, there are several types of triazine-based compounds that have historically been used. Unfortunately, if not closely monitored, the by-products of many of these chemistries can actually be more operationally detrimental and thus vastly more expensive, because overuse may cause corrosion and fouling in downstream systems. Fortunately, new technology has emerged! Q2 Technologies boasts a revolutionary new product that is in a class all by itself: Pro3® is an innovative non-triazine and non-amine H2S scavenger for Crude Oil and liquid hydrocarbon applications that is able to reduce chemical use up to 50-75% as compared to Glyoxal and MEA Triazine.

Less chemical

Pro3®’s active ingredient is chemically more effective and efficient at rendering H2S into non-reversible components than triazine could be, chemically speaking Pro3® is superior to triazine.

In a recent study, Pro3®, a non-triazine scavenger, was recommended to substitute a 40% MEA-triazine scavenger, resulting in an 80% cut on chemical consumption compared to triazine. This resulted in a reduction in deliveries and lowered the overall chemical spend. Read more about this case study here.

No Fouling and Corrosion

Q2 Technologies’ non-triazine product does not contain any amines or nitrogen compounds, making it 100% safe for refineries and pipelines. Amine salts from triazines can end up doing more damage to the top stacks of a refinery when heated to +500 °F as compared to the pinhole corrosion that H2S would cause if routed through the refinery untreated. 

The distillation column is the backbone of any refinery and keeping the internals free of corrosion is critical. Refineries that manage asset integrity are constantly evaluating the inlet volume for amines and monitoring the physical nature of the columns.

Effect on supply chain

In the Spring of 2021 there was a significant winter storm event in Texas which had far reaching implications for the triazine market for much of the United States, and consequently Canada and parts of South America. The week-long deep freeze shuttered many chemical plants, and by the company’s estimates, nearly 90% of plants along the Gulf Coast that create the raw materials for triazine were shut down for months. This caused the near-commodity price of triazine to skyrocket: a classic under supply situation resulted in higher demand and the Oil & Gas producers and consumers were hindered by this for over a year. Q2 Technologies monitored this phenomenon closely.  Since our Pro3® is a non-triazine based product, there were no supply chain issues and prices were not affected. Unfortunately, for those that depend heavily on triazine as a main scavenger, the threat of a shutdown could easily happen again, as some plants simply did not come back online in the summer of 2021, and those that were were repaired carry the additional operational burden to produce more and more triazine.

If scavenger costs and operational concerns are a priority, learn more about Pro3® and see how Q2 Technologies can lower your net chemical usage, protect infrastructure, and increase overall hydrocarbon production by rending H2S out. If you think your project can benefit from using Pro3® contact us today.