Moisture Dehydration Solution with Molecular Sieve Desiccant Adsorbents

Nature has blessed us with uncountable resources; some can be used directly, while others need to undergo a purification process. This is true for natural gas as well. To harness its full potential, natural gas must undergo a purification process in a gas processing plant to remove impurities that can hinder its performance. Whether it’s being used for power generation, petrochemical production, or transportation, ensuring its purity is essential.

Natural gas extracted from underground reservoirs does not come in its purest form. It has to undergo industrial separation processes that eliminate impurities, resulting in dry gas suitable for transportation and consumption.

In this guide, we’ll explore the purification processes that natural gas goes through to meet the demands of various industries.

What is Natural Gas Purification, and Why is Removing Its Main Impurities Necessary?

Raw natural gas consists majorly of methane (the main component used for energy) and ethane, but it also contains other impurities such as -

1. Water Vapor (H₂O)

The natural gas extraction from the well contains water vapor, which, if not removed, can condense into liquid water, causing issues such as reduced energy content and clogged pipelines.

2. Carbon Dioxide (CO₂)

Carbon dioxide can be present in concentrations ranging from 10-20 mol% to as high as 70 mol%. Gas containing high volumes of CO2 cannot be burned safely and can react with H2S and H2O to make corrosive compounds that threaten steel pipelines.

3. Hydrogen Sulfide (H₂S) – "Sour Gas"

Natural gas containing high amounts of hydrogen sulfide is also known as sour gas due to its foul smell, toxicity, and flammability. It can pose potential health risks to humans and can damage pipelines.

4. Mercury (Hg)

The concentration of mercury in natural gas can cause problems such as corrosion, equipment damage, poisoning the catalyst, and raising environmental concerns.

It is essential to purify natural gas to ensure safer and more efficient use. This purification not only affects pipelines but also has implications for the environment. For instance, the United States has strict regulations regarding the emissions of harmful gases, which require industries to adhere to specific environmental standards.

Key Equipment Used in Natural Gas Purification and Their Functions

To remove impurities from natural gas, we require the equipment mentioned below. These are important to ensure that natural gas is safe, efficient, and clean before being utilized in houses, industries, and power plants.

•  Separators: 

The first step towards the purification of natural gas is done using a separator. The gas passes through it and removes liquid like water and heavy hydrocarbons (oily substances) in massive amounts. 

•  Amine Absorption Units: 

Anime absorption units are machines that remove harmful gases such as carbon dioxide (CO₂) and hydrogen sulfide (H₂S) from natural gas. In brief, this is a process where a chemical called amine is used to clean the gas; when the natural gas passes through the unit, the amine reacts with harmful gases and absorbs them.

•  Sulfur Recovery Units (SRUs):

The sulfur recovery unit helps convert hydrogen sulfide into solid sulfur, which is later sold and used in the making of fertilizers, batteries, rubber, and chemicals. 

•  Cryogenic Separation Units: (Air Separation Units)

The air is separation unit is removing Moisture, Co2 and Hydrocarbon With the help of Molecular Sieve and Alumina Balls, then the cryogenic gas plant uses freezing temperatures to separate natural gas liquids (NGLs) from natural gas. Now, the NGLs include - ethane, butane, and propane; they are valuable and helpful in many industries, so they are sold separately afterward. 

•  Dehydration system: 

Glycol dehydration is a process that is used to remove water vapor from natural gas; it prevents the forming of ice-like substances in the pipeline. The process works in the way that the natural gas passes through a liquid called glycol; it then absorbs the water from the gas and leaves it dry, eliminating the risk of freezing.

•  Mercury removal system: 

Small size yet significant effect, yes, that's true when we talk about mercury; despite the quantity present in natural gas, the damage is always severe. In LNG plants and cryogenic units, the presence of mercury would do massive damage to aluminum equipment, pipelines and machinery. 

The Process of Natural Gas Purification 

Natural gas processing is a step-by-step method to remove impurities from the natural gas. Let's take a look at the significant steps - 

1. Raw Gas Pretreatment

The first step in natural gas purification is raw gas pretreatment; as the name suggests, it is all about cleaning up the raw gas, removing large impurities, and setting the gas up in the right conditions for the rest of the purification process.

 When natural gas is excreted from the ground, it is accompanied by oil, water, and dirt. The unwanted elements are removed using types of equipment’s such as separators and filters. 

The pretreatment also involves controlling the temperature and pressure of the gas; natural gas needs to be at the right temperature and pressure for the next steps in purification to work correctly.

2. Acid Gas Removal

Acid gases like hydrogen sulfide and carbon dioxide are removed during the purification process of natural gas. Now, these gases need to be controlled as they pose a serious issue for both the environment and further operations. 

Problems such as - corroded pipelines, blockage in equipment, lowering the energy content of natural gas, freezing during specific processes, etc. 

Amine absorption is the solution to this problem! The amines react with H₂S and CO₂, capturing these gases and removing them from the gas stream. 

Physical methods such as molecular sieve adsorption or pressure swing adsorption are used for further purification. The following techniques are used when an ultra-pure gas is required, removing almost all sulfur from natural gas. 

3. Dehydration 

The dehydration process is necessary to prevent hydrate formation in the pipeline because water vapor combines with natural gas to form hydrates(ice-like crystals), blocking the pipelines and causing other serious issues such as loss of gas flow and operational interruptions. 

Water in natural gas causes corrosion in pipes and equipment, which damages the machinery and shortens its lifespan with costly repairs. 

To protect other processes, like cryogenic separation and sulfur recovery that comes after dehydration, it's essential to remove water from the natural gas. 

So now you know why Dehydration is needed! Let's jump onto the Dehydration process. There are four main methods for dehydration- 

1. Primary Dehydration with Glycol: Primary Dehydration with Glycol is one of the most common methods to remove water from natural gas. Triethylene glycol (TEG) is a liquid that passes through the gas stream, absorbing the water vapor from the gas. The final gas will have less than 7 lbs of water per million standard cubic feet (lbs/MMscf), which meets the standards for pipeline-quality gas.

2. Molecular Sieves (for higher moisture content): When the water content in the natural gas is high, 4A molecular sieves are used for an efficient purification process, especially in low-temperature conditions. 

3. 13X Molecular Sieves are used for deeper drying of natural gas; they are a type of adsorbent material made up of zeolite crystals. Zeolites are porous materials that can trap and hold molecules such as water. The 13X molecular sieves have a high affinity that enables them to remove water even at low concentrations (as low as 0.1 parts per million, or ppm)

4. Activated alumina is used for moderate drying and helps achieve moisture levels like a dew point of -40°C. The activated alumina has a porous structure, high surface area, and high water adsorbing capacity, which makes it the best option for moderate drying. A cost-effective solution to remove bulk water load.

4. Removal of Heavy Hydrocarbons and Mercury

Certain harmful chemicals, such as heavy hydrocarbons and mercury, need to be removed, even if they are in their smallest form. Hydrocarbons (large molecules) solidify in low temperatures, blocking the pipes and equipment. 

On the other hand, mercury can corrode aluminum parts in cryogenic heat exchangers, causing them to break down and leading to heavy repair expenses. Molecular sieves (5A,13X) are the most widely used advanced adsorbents to remove these impurities like moisture, CO2 and Hydrocarbons.

The molecular sieves 5A and 13X are very good at trapping both heavy hydrocarbon and mercury. Molecular Sieve is best known for working at low temperatures, a much-needed element in cryogenic systems. They are reusable and cost-effective, making them the best choice for the longer run. 

Activated carbon: Activated carbon is also used in the removal of mercury. However, it's always considered as a second choice.

Purity Requirements for Natural Gas in Different Industries

Various industries have different purity requirements for natural gas to ensure that their equipment is not damaged. Second, they want natural gas to be purified in certain ways that fit best for their use. Here is a list of a few industries and their purity requirements. 

Different industries have different requirements for natural gas purity depending on what the gas will be used for:

•  Pipeline transportation:Needs to be free of water, acid gases, and impurities to prevent corrosion and blockages.
•  Power plants need to be dry to avoid corrosion in equipment.
•  Petrochemical applications: Needs to be free of sulfur and hydrocarbons to avoid interference with chemical reactions.
•  NGL production: Needs to be very dry and free of CO₂ to avoid freezing and contamination during the separation process.
•  Oil refineries and specialized applications Need specific control over sulfur, moisture, and hydrocarbon composition for efficient and high-quality production.

In natural gas treatment, desiccants such as Alumina Balls and Molecular sieves are the best choice for achieving these purity levels because they are highly effective, selective, and regenerative, which makes them a cost-effective solution for long-term use.

Molecular sieve beads are tiny, porous particles that help capture molecules based on their size. They are commonly used and applied in various processes and important applications as desiccants to eliminate moisture from gases and liquids. The material can be used multiple times making it an affordable and sustainable adsorbent solution by regenerating it once fully saturated. In this blog, we will understand the regeneration process for molecular sieve beads and how it allows the beads to be used multiple times.

Types of Molecular Sieves

There are different types of molecular sieve desiccant that are used in various industrial processes and applications according to their pore sizes.

3A Molecular Sieves: They have a pore size of about 3 angstroms and are used to dry gases and liquids by removing excess moisture or water content from them. These sieves are used as desiccants in the petroleum and chemical industries for drying unsaturated hydrocarbons like ethylene and propylene, as well as polar liquids such as methanol and ethanol. They are commonly used in the chemical and pharmaceutical industries for maintaining purity levels in solvents and preventing moisture contamination in packaging. 3A molecular sieves have a three-dimensional structure, higher mass transfer efficiency, and crush strength.

4A molecular sieves: These have a slightly larger pore size than 3A sieves and can efficiently adsorb water, ammonia, and carbon dioxide, making them useful for drying non-polar solvents and maintaining purity in petrochemical products and byproducts. They are also used in pharmaceutical applications to dry solvents and maintain low humidity levels. 4A molecular sieves have a strong ability to adsorb and a preference for smaller molecules, which makes them useful in many industrial uses.

5A Molecular Sieves: 5A molecular sieves have a larger pore size when compared to 3A and 4A sieves, helping them adsorb larger molecules. Their larger pore size makes them effective in removing impurities from natural gas and other hydrocarbon streams. They are known for their high adsorption capacity and are used in the petrochemical industry for drying and purifying gases and liquids. Widely used in VPSA plant for separation of Oxygen and Nitrogen.

13X Molecular Sieves: These sieves have the largest pore size of 8-10 Angstrom, allowing them to adsorb even larger molecules that are characterized by their high adsorption capacity and are used in applications requiring the removal of larger molecules, such as oxygen from food packaging and in Pressure Swing Adsorption (PSA) systems for producing medical-grade oxygen. The large pore size of 13X molecular sieves makes them suitable for a wide range of industrial applications and processes.  In Air Separation Unit in Oxygen and Cryogenic Plant, LPG Sweetening (Removal of Mercaptan).

Zeolite-Based Molecular Sieves

Zeolite-based molecular sieves also offer unique properties and applications in various industries. Here are the different types available.

3A Zeolite: These zeolites have a small pore size, that helps them adsorb water and other small molecules. They are mainly used in various drying applications, particularly for polar solvents like ethanol. 3A zeolites are known for their high thermal stability and are often used in drying processes where temperature control is important and required. They have many unique properties such as they can effectively exclude larger molecules, making them ideal for maintaining purity in chemical processes.

4A zeolites: They have an excellent adsorption selectivity, and a slightly larger pore size than 3A zeolite, to adsorb water, ammonia, and carbon dioxide, making them useful for drying non-polar solvents and maintaining purity in petrochemical as well as other various industrial applications.

5A Zeolite: These zeolite materials have a larger pore size, that effectively adsorb larger molecules, and that’s why are commonly used in the petrochemical industry for drying and purifying gases and liquids as they have a strong affinity for hydrocarbons. The high adsorption capacity of 5A Zeolite makes it effective in removing impurities from natural gas and other hydrocarbon streams.

13X zeolites: 13X zeolites are highly versatile due to their large pore size, allowing them to adsorb a wide range of molecules as compared to the other zeolite types and sizes. They are used in PSA systems for oxygen production and in air purification systems.

Applications of Molecular Sieve Beads

Molecular sieve beads are widely used in drying and purification processes across various industries.

Petrochemical Industry: Molecular sieves desiccants are used to dry and purify gases and liquids, ensuring the removal of impurities and moisture, which is required for maintaining product quality and preventing equipment damage.

Gas Processing: In natural gas processing, molecular sieve beads help remove water, vapor, and other impurities, which is important for preventing ice formation and maintaining pipeline quality and operations effectively.

Compressed Air Drying: Molecular sieves are effective in drying compressed air, reducing the dew point to very low levels, and thus are beneficial in these industrial applications. This is important for preventing moisture-related issues in pneumatic systems.

Pharmaceuticals and Electronics: Molecular sieve beads are used to maintain dry conditions in packaging for drugs and electronic components, preventing moisture damage during long durations of transit and storage.

Industrial Oxygen Generation: Molecular sieve beads play a key role in Pressure Swing Adsorption (PSA) systems for producing medical-grade oxygen by separating oxygen from air.

Regeneration of Molecular Sieves

Regenerating molecular sieves during usage, once they are saturated to their full extent, is helpful and necessary for restoring their adsorption capacity and extending their lifespan. This method keeps operations running smoothly and lowers expenses by preventing the need for regular replacements.

Various methods of regeneration

The regeneration process generally involves heating the molecular sieve desiccants to release adsorbed humidity, water, or vapour substances. This can be done by raising the temperature which is usually between 200-320°C, and reducing pressure, or by using a pure gas to purge the adsorbent material. Pressure swing adsorption (PSA) and temperature swing adsorption (TSA) are also effective methods that are widely and popularly used for the regeneration molecular sieves.

The best practices and challenges

For the regeneration of the sieves desiccant, the best practices include selecting the right regeneration method for each sieve type, monitoring and maintaining proper required temperature and pressure, and avoiding over-regeneration of the material. Some of the very common challenges include potential damage from excessive heat and the need for careful monitoring to maintain the adsorption capacity of the desiccant material, and proper regeneration can significantly reduce waste and operational costs for use in various industrial processes and applications effectively.

Conclusion

In summary, molecular sieve beads come in various types, each with unique properties and applications. They are important and are used in various industries like petrochemicals and gas processing for drying and purification. It is important to choose the right type and follow best practices for regeneration to make the most of the desiccant material and its properties. We encourage you to apply these insights in their own processes to improve efficiency and reduce costs. This approach can improve the performance and lifespan of your molecular sieves, resulting in more successful operations.

Molecular sieves are a very reliable, safe, and efficient adsorbent material and solution that are used in various processes and applications across industries. The material has a high absorbency capacity when compared to other desiccants and adsorbents and has tiny pores that can trap moisture and impurities, which is essential for preventing damage and maintaining performance. In the refrigeration industry, they effectively help keep refrigeration systems running well by getting rid of excess moisture, which lowers the chances of corrosion and other problems.

What are Molecular Sieves?

Molecular sieves are special materials with tiny, uniform pore structures that can very efficiently trap specific molecules based on their pore size and polarity. They are applied in many applications and processes for their unique properties and in refrigeration systems, they help remove moisture and impurities from gases and liquids.

This process ensures that the system runs efficiently and prevents damage like corrosion. The mechanism of selective adsorption means that only certain molecules fit into the pores, allowing molecular sieves to target water vapor and other unwanted substances effectively.

Zeolites in Refrigeration

Zeolites are very useful in refrigeration due to their unique properties. They are mainly a type of molecular sieve made from microporous aluminosilicate minerals, and have tiny, well-defined pores that allow them to selectively trap certain molecules, making them very useful in refrigeration.

Zeolites have unique properties and ability to adsorb water vapor, even at low partial pressures. This means they can effectively remove moisture from refrigerants and air, which is important and beneficial for preventing problems like corrosion and freezing in refrigeration systems which can lead to breakdown or short circuits in the equipment. They also protect the equipment and prevent mold formation due to excess humidity, which can damage the refrigeration process.

Zeolites help maintain a dry environment, improving efficiency and increasing the lifespan of equipment by protecting the equipment from the detrimental factors such as varying or excess levels of moisture or humidity. And since they have a natural presence and high effectiveness they are a popular choice for cooling applications across various industries.

Moisture Control in Refrigeration Systems With Molecular Sieves

Molecular sieves are used for controlling moisture levels in refrigeration systems, and mainly work by using tiny pores in their material that can trap water molecules effectively. When air or refrigerant passes through these sieves, the moisture is adsorbed, preventing it from causing problems in the system, which is important because excess moisture can lead to corrosion, freezing, and reduced efficiency.

Here the mechanism of working of the molecular sieves in the refrigeration systems involves the selective adsorption principle of the material, which can target water vapor while allowing other gases to pass through. This feature keeps the refrigeration system dry and running well, and protects its important parts and equipment from rust, corrosion, mold growth, and other damage due to high humidity.

Refrigeration is important for many industries such as food and medicine preservation. Thus it is required to maintain low moisture levels to improve the performance and lifespan of cooling equipment, and in turn, reduce maintenance costs of sensitive and important refrigeration systems and equipment.

Advantages Of Using Molecular Sieves Over Traditional Desiccants In Refrigeration Systems

- Using molecular sieves in refrigeration systems offers several advantages over traditional desiccants. First, molecular sieves have tiny, uniform pores that allow them to selectively trap water molecules while letting other gases pass through. This selective adsorption property may not be found in other desiccant varieties.

- Molecular sieves can adsorb more water than traditional desiccants, making them more effective in preventing problems like corrosion and freezing on a large scale of application. This is especially important in places where high humidity can affect refrigeration performance.

- Molecular sieves do not require frequent replacement or regeneration, leading to lower maintenance costs. 

- They are also more durable and can withstand harsh conditions, providing a longer lifespan in refrigeration applications.

Conclusion

It is best to use high quality molecular sieves or Zeolites for your refrigeration systems to make sure they function well throughout their efficient life. Sorbchem India is the largest supplier of molecular sieves of different sizes and forms. Check out our products and choose the right one for your customized needs.

Aerosol products need to be maintained in their high quality and away from contaminants, moisture, dust, and other gases, that is why the use of molecular sieves can help achieve this in the most effective way. Molecular sieves, especially 13X molecular sieves, are available in beads and pellet shapes, and thus are applied and used in various processes and applications to keep aerosol products clean and effective by filtering out harmful chemicals, gases, Odor, and contamination.

Since aerosol products deal with perfume, good smell, and fragrance, the gases need to be passed through a bed of molecular sieves to effectively remove any bad Odor that may be present in them, as this can affect the aerosol product quality. 

In the aerosol industry, 13x molecular sieve removal mercaptan is mainly used for eliminating mercaptan which is a chemical that can produce bad smells and odors in products such as LPG and aerosol sprays. Mercaptan is used in LPG to find gas leaks, but it can also spoil the smell of perfumes and deodorants because of its strong odor, as perfumes and other fragrances should actually smell in a nice way and should be appealing.

By using 13X molecular sieves in the process, and effectively passing LPG through beds filled with 13X molecular sieves, LPG manufacturers can remove mercaptan, making sure their aerosol products smell good and are of high quality. This step is important for producing good-smelling and effective aerosol products for consumers like perfumes, fragrances, etc.

Why are 13x Molecular Sieves Used in the Aerosol Industry?

13X molecular sieves are used in the aerosol industry for various reasons, due to their high efficiency and, useful properties.

- The 13x molecular sieves material is very tough and can handle a lot of pressure without breaking. This is very much useful when dealing with large scale applications in the aerosol processes and applications since they can be used safely in aerosol products without worrying about damage.

- 13X molecular sieves have larger pores which is about 10 angstroms (10Å), this allows them to adsorb bigger molecules like water and carbon dioxide, which are often unwanted in aerosol products and need to be removed.

- They can hold a significant amount of moisture and impurities, which is very helpful during the manufacturing and storage of the various aerosol products to ensure that products remain stable and effective over time and throughout their shelf life.

- The material has selective adsorption qualities, and 13X molecular sieves can specifically target and remove certain contaminants, like mercaptans, which can affect the quality of aerosol products to effectively adsorb and remove them.

- Unlike some other materials, 13X molecular sieves cannot be reused or regenerated after they have absorbed substances. This means that they need to be replaced to make sure the processes are running smoothly and functioning properly, to keep products fresh and effective every time.

- By efficiently removing moisture, contaminants, dust, gases, and other impurities, 13X molecular sieves can greatly help extend the shelf life of aerosol products, keeping them fresh longer and throughout the shelf life of storage, transportation, or cargo.

Nowadays, people are preferring nitrogen for tyre inflation instead of regular air. This is to keep the vehicle safe and running smoothly for long periods of time. Nitrogen keeps tires inflated longer and lowers the chance of them bursting. Carbon molecular sieves are important for cleaning nitrogen by getting rid of oxygen and other unwanted substances. Thus, using them in tire inflators helps get pure nitrogen, improving tyre performance and making driving safer.

How do Carbon Molecular Sieves Work For Nitrogen Purification?

Carbon molecular sieves are highly adsorbent materials that can adsorb various gases based on their size. This allows for high-quality purification of the gases, and pure nitrogen can be obtained. In the purification process, when air is compressed and passed through the medium, the sieves can selectively adsorb oxygen and moisture efficiently, allowing only nitrogen to pass through and thus be purified.

This method is called pressure swing adsorption, and in this process, the air is compressed and cleaned to remove impurities and contaminants present in the mixture. Next, it goes into a bed of carbon molecular sieve, where small oxygen molecules get caught, and big nitrogen molecules pass through, providing nitrogen that is upto 99.9% pure and efficiently separating nitrogen.

Why Use Carbon Molecular Sieves For Nitrogen Purification?

There are many reasons and benefits of using carbon molecular sieve for nitrogen tyre inflator.

High Purity Levels: Carbon Molecular Sieves can help produce pure nitrogen which is important for tyre performance, as pure nitrogen keeps tyre pressure longer and reduces rubber oxidation, which makes tyres last longer. The pores in carbon molecular sieves are designed to be just the right size to allow nitrogen molecules to pass through while blocking larger oxygen molecules.

High Efficiency and Speed: You can quickly generate nitrogen using Carbon Molecular Sieves, which is essential for busy tyre service centers. The PSA process is continuous, meaning that as one chamber is purifying nitrogen, another can be regenerating, ensuring a steady supply.

Cost-Effective: Making nitrogen locally by using Carbon Molecular Sieve Nitrogen Generator is usually cheaper than buying it in bottles, which can save a lot of money, especially for companies that need a lot of nitrogen.

Chemical Properties: The sieves have chemical properties that attract and hold onto oxygen and impurities better than nitrogen, capturing any oxygen that slips through quickly.

The PSA nitrogen purification method, along with the special characteristics of carbon molecular sieves, is a great option for creating pure nitrogen. This new technology improves tire performance, making driving safer and more efficient. Sorbchem India is the largest supplier of carbon molecular sieves, and we provide premium quality products to various industries and applications worldwide.