We are Yixing Wencheng Chemical Co., Ltd., a manufacturer specializing in polyols—including triethylene glycol (TEG)—with over 30 years of experience in the production and sales of polyols and their derivatives. TEG serves as a specialized dehydrating agent for natural gas, oilfield gas, and refinery gas. Thanks to its exceptional hygroscopic properties, low volatility, thermal stability, and ability to undergo high-temperature regeneration, TEG has become the standard solvent for natural gas purification worldwide.Approximately 65% to 70% of global TEG consumption occurs within the oil and gas industry, where it is utilized across four key application areas. Drawing on our domestic and international sales experience as well as on-site operational insights, I would like to share some of our expertise with you, in the hope that it proves useful to those interested in the subject.
What are the four key application areas for triethylene glycol in the oil and gas industry, and what specific details require attention? I will share this information below for those interested.
1. Natural gas dehydration at onshore and offshore wellheads and gas gathering stations
TEG is suitable for the dehydration of gas from conventional fields, shale gas formations, and coalbed methane (including associated gas). Thanks to its acid-resistant properties, it is also effective for dehydrating sour gas (containing H₂S/CO₂). It is worth noting that the purity of TEG drops from ≥99% to 93%–96% after absorbing moisture. Discarding the diluted TEG at this stage would be highly wasteful; given TEG’s high boiling point and negligible evaporative loss, the absorbed water can be removed through heating, allowing the TEG to be restored to high purity and recycled. For TEG used in sour gas (H₂S/CO₂-rich) dehydration, a stripping regeneration process can be integrated to simultaneously remove dissolved sulfur components, thereby extending the solvent's service life.
2. Dehydration at large-scale natural gas purification plants and the initial stations of long-distance transmission pipelines
The standard for outgoing commercial gas specifies a water content of ≤112 mg/m³; therefore, compliance relies entirely on deep dehydration using TEG. Purified gas—having undergone amine-based desulfurization and decarbonization at the plant—must undergo deep TEG dehydration before entering the long-distance transmission pipeline.
3. Deep Dehydration Upstream of the LNG Liquefaction Unit (Essential Pre-treatment for LNG)
Before natural gas enters the cryogenic liquefaction unit (-162°C), it must undergo deep dehydration using TEG to achieve a dew point below -50°C. Given the cryogenic operating conditions, even trace amounts of moisture can freeze and cause blockages in heat exchangers and liquefaction cold boxes. TEG is the standard dehydration agent for LNG plant pre-treatment; TEG dehydration systems are installed at coastal LNG receiving terminals and inland liquefaction plants worldwide.
4. Purification and drying of refinery dry gas, flare gas, CO₂-EOR gas, and associated CO₂ from oilfields
To prevent pipeline freezing/blockage and equipment corrosion, these gases require moisture removal using TEG prior to recovery.
Many people might wonder: why choose triethylene glycol (TEG) as a dehydrating agent instead of diethylene glycol (DEG) or monoethylene glycol (MEG)? What is the primary reason the oil and gas industry selects TEG?
1. TEG has a high boiling point (285°C) and extremely low vapor pressure: its evaporative loss at ambient temperature is less than one-third that of DEG and less than one-tenth that of MEG, resulting in minimal makeup requirements during long-term operation.
2. TEG has a high water-absorption capacity: for a given mass, it absorbs more water than DEG, allowing for lower circulation rates and a smaller equipment footprint.
3. TEG exhibits excellent thermal stability: it undergoes minimal thermal degradation during regeneration at 200°C and demonstrates superior stability in the presence of acidic media (H₂S/CO₂).
4. TEG achieves a deeper level of dehydration: it can reach a minimum dew point of -50°C, meeting the requirements for LNG production and ultra-high-pressure CO₂ drying (whereas DEG can only achieve approximately -25°C).
The oil and gas industry imposes specific quality requirements on triethylene glycol (TEG). TEG intended for this sector generally requires a purity of over 99.5% (though some applications specify a minimum of 99%), while high-sulfur gas fields and LNG facilities utilize products with 99.8% purity or higher, strictly limiting impurities such as water, ethylene glycol, and diethylene glycol. Parameters regarding acid value, iron ions, chloride ions, and hydrocarbon content must meet established standards to prevent equipment corrosion and solvent foaming. The product must be colorless and transparent, exhibit excellent anti-foaming properties, and resist thermal degradation or coking during high-temperature regeneration. Yixing Wencheng Chemical Co., Ltd. manufactures TEG that meets these specialized oil and gas industry requirements.
Our company offers a range of high-quality polyols—including triethylene glycol (TEG)—characterized by stable performance and superior quality. Exported to numerous countries worldwide, these products are widely used in the oil and gas industry, as well as in applications such as aromatics extraction solvents, plasticizers, and lubricant raw materials. With thirty years of deep industry experience, we remain committed to quality and production stability, and we warmly welcome customers from all sectors to contact us for consultations and potential collaboration.
