The interesting points of this example lie in the use of the absorption module for the contactor model and in the representation of two columns connected in series the teg regenerator and the teg stripper by a single prosimplus stripper module. Troubleshooting a glycol dehydration system oil and gas. Produced gas is saturated with water, which must be removed for gas transmission glycol dehydrators are the mostcommon equipment to remove water from gas 36,000 dehydration systems in natural gas production, gathering, and boosting most use triethylene glycol teg glycol dehydrators create emissions methane, vocs, haps from reboiler vent. Natural gas dehydration damascus citizens for sustainability. Because most of the water vapor has to be removed from natural gas before it can be commercially marketed, all natural gas is subjected to a dehydration process. Pdf dehydration of natural gas is needed to remove the water that is associated with natural gases in vapor form. Natural gas is moved by pipelines from the producing fields to consumers. The axes are water content in the wet gas, in lbmmscf and dry gas dew point, in f. The lg liquid gas coalescers utilizes proprietary, high performance all syntheticcoalescing media in a pleated configuration. The mathematical model found that urea was the most profitable process for natural gas field flow rates higher than 5 mmscfday. Dehydration is necessary to ensure smooth operation of gas transmission lines prevents the formation of gas hydrates and reduces corrosion. Need to dry gas to dew point below lowest operating temperature plant operations need 4 to 7 lbmmscf 85 to 150 ppmv in pipeline glycol dehydration most common to produce water contents down to 10 ppmv need to have less than 1 ppmv h 2 o in gas to cryogenc units glycol dehydration cannot get to these low water levels mole sieves. The second dehydration method is adsorption of h 2o.
Natural gas dehydration unit with teg tri ethylene glycol. Removal of water from natural gas by lowering the dew point temperature of the natural gas. The gas industry normally uses adsorption dehydration units upstream of a liquefied natural gas lng plant or a deep natural gas liquid ngl extraction plant where the gas temperature reduces to less than 160 c 256 f and 100 c 148 f, respectively. Simulation of gas dehydration on an fpso using aspen hysys. Glycols typically seen in industry include triethylene glycol teg, diethylene glycol deg, ethylene glycol meg, and tetraethylene glycol treg.
Mokhatab, gas processing consultant, halifax, nova scotia, canada. Major gas fields were discovered in the 80s and 90s. Glycol dehydration most common to produce water contents down to. Natural gas, in itself, might be considered a very uninteresting gas it is colorless, shapeless, and odorless in its pure form, but it is one of the cleanest, safest, and most useful of all energy sources etuk, 2007. Typically one bed is drying gas and the other is being regenerated.
Tegi t i b ti tteg is most common in absorption systems meg is most common in glycol injection systems. Michael sinagra has over 35 years production equipment experience and is recognized throughout the industry for being an expert in the area of production equipment with emphasis on triethylene glycol regenerative gas dehydration systems. The natural gas feed should be completely dry, even from the smallest traces of water molecules dehydration of natural gas must begin at the source of the gas in order to protect the transmission system. Gas hydrates are crystals of natural gas and water which can appear fare above. High pressure, low velocity gas can be handled with a relatively small diameter tower. For plants where significant amounts of propane or ethane are recovered, the industrystandard dehydration technology is molecular sieve desiccant. As such, the title capex and opex considerations for gas dehydration technologies can be interpreted in several ways. Modeling and simulation of natural gas dehydration reactor. The countless hazards that come with the use of a teg unit make pds units a unanimous solution to safe natural gas dehydration. Produced gas is saturated with water, which must be removed for gas transmission glycol dehydrators are the most common equipment to remove water from gas 36,000 dehydration units in natural gas production, gathering, and boosting most use triethylene glycol teg glycol dehydrators create emissions methane, volatile organic compounds. Gas dehydration free download as powerpoint presentation. Why gas dehydration gas dehydration is an important process in on and offshore gas. Natural gas is an important energy source among other sources of fossil fuels.
Our emission free dehydrators are a reliable, costeffective, and clean way to dehydrate your natural gas streams. Glycol dehydration systems are not only efficient at removing water from a natural gas stream, they also remove benzene, toluene, ethylbenzene, and xylene btex as well as other volatile organic compounds vocs. Feb 14, 2016 dehydration of natural gas is the removal of the water that is associated with natural gases in vapor form. Molecular desiccant in natural gas dehydration process. Molecular sieve for natural gas drying water or other impurities present in the natural gas can increase the risk of damage to the pipeline as the result of corrosion or hydrate formation. The natural gas dehydration process is selected based on the water dew point. This research is considered as an introduction for designing a natural gas processing plant it concerns with natural gas processing systems sweeting, dehydration, fractionation, liquefaction and recovery as an example for natural gas processing. Modelling of natural gas sweetening and dehydration processes. May 24, 2017 gas dehydration is the removal of water from the gas stream in order to meet pipeline specifications. Optimal design and operation of molecular sieve gas.
The sweetened natural gas leaves the top of the contactor saturated with water and so dehydration is normally required before the gas is sold or fed to a cryogenic gas plant. The last 25 years have seen a remarkable growth in the contribution of gas to the worlds total primary energy demand. To perform a good troubleshoot on glycol dehydration equipment, you must know what the system is designed for and how the current conditions compare to that design. Glycol dehydration process an overview sciencedirect topics. Natural gas is an important source of energy and is a naturally occurring fuel found in oil fields. The gas remains there until it is added back into the pipeline when people begin to use. Exterrans unit provides you with reliability, efficiency and flexibility in a single package and a wide range of options to meet your needs. Optimization of natural gas dehydration using triethylene. This paper compares three methods for natural gas dehydration that are widely applied in industry.
Comparison of three methods for natural gas dehydration. This work dehydration of natural gas using triethylene glycol teg as the dehydrating agent, examined the amount of water removed from the natural gas stream when the dehydrating agent and the gas, flow in counter current manner in a contacting column. These facilities typically consist of a molecular sieve dehydration, optional mechanical refrigeration, turbo expandercompressor and demethanizer to drop the temperature of the gas and remove condensed ethane and other natural gas liquids. The dehydration of natural gas is very essential in the gas processing industry to remove water vapor. Since natural gas demand is greater in the winter, gas is stored along the way in large underground storage systems, such as old oil and gas wells or caverns formed in old salt beds.
Natural gas utilities typically transport natural gas from delivery points located on interstate and intrastate pipelines to households and businesses through small diameter distribution pipelines. Natural gas is the gas obtained from natural underground reservoirs either as free gas or gas associated with crude oil. Glycol dehydration troubleshooting guide oil and gas. Natural gas dehydration unit dehydration of natural gas. The gas is colorless and odorless, but generates a great deal of energy when combusted. Ethylene glycol hoch 2 ch 2 oh was, initially, the principal chemical agent in this process, has a very strong affinity for water and when the glycol is in contact with a stream of waterwet natural gas. Natural gas dehydration technologies teg glycol, membrane.
This report is therefore introduced with a brief description of the danish off. Pdf on oct 31, 2012, michal netusil and others published natural gas dehydration find, read and cite all the research you need on. First, co2 and h2s removal stage which is constructed to assure that co2 would not exceed 50 ppm in the natural gas feed. Schlumberger glycol dehydration processes remove water vapor from natural gas, which. Hysys can handle multiphase flow modeling, gas processing and refinery reactors. Optimal design and operation of molecular sieve gas dehydration unitspart 1. Regeneration is done by preheated gas, as it is depicted on the. New lg liquid gas coalescers are designed to remove aerosols and fine particulate contaminants from natural gas streams. Raw natural gas requires dehydration in order to avoid the formation of hydrates, reduce corrosion, and meet sales specifications before it is sent downstream. This can be done either by adsorption or absorption processes. Uses absorption process to transfer water into the glycol. Glycol dehydration is a liquid desiccant system for the removal of water from natural gas and natural gas liquids ngl. Pdf a study of the dehydration process of natural gas in iraqi. All raw natural gas is fully saturated with water vapor when produced from an underground reservoir.
Mol sieve dehydration is a process where water vapors are removed from the gas streams using the highly effective desiccant material known as molecular sieves. Dew point is the temperature to which a gas must be cooled in order to become saturated with water. Gas dehydration field manual defines the various methods of gas dehydration and discusses the differences between adsorption and absorption. Among our experience there are units in sour service more than 20 ppmv of h 2 s, the largest silica gel gas dehydration plants in the world and units located offshore. Herold, contributing writer, amsterdam, the netherlands. The idea of a dehydration system for gas processing is a fairly simple one. Dehydration of low pressure natural gas oil and gas process. Water is removed from the natural gas also to avoid freezing in the pipeline of the liquefaction process. Process design project, 2011 fall personal webpages at ntnu. The nonpermeated gas, mainly ch 4, remains at process pressure and becomes the product gas membrane dehydration. Secondly, ng storage enables the maximum capacity of distribution lines to be exploited. Water molecules in the gas adhere to the desiccant as the natural gas passes through, with the gas ultimately leaving dry at the bottom.
An example of natural gas dehydration, using teg, was built with prosimplus. Dry glycol flows down the tower from the top, from tray to tray or through packing material. Exterran is the rst choice for gas processing plants. Natural gas dehydration by desiccant materials sciencedirect. Troubleshooting a glycol dehydration system is a bit more nuanced but the authors quote pretty much forms the basis for the process. Natural gas dehydration experts a t van gas technologies have decades of experience and have encountered virtually every application imaginable. Gas hydrates have a crystalline struc ture similar in appearance to water crystals, but their form ation occurs at considerably higher temperatures. Natural gas is favored as a fuel source because unlike other energy sources, the combustion of natural gas is clean and does not emit harmful substances into the atmosphere. Updated and more practical than ever, natural gas hydrates, third edition helps managers and engineers get up to speed on all the most common hydrate types, how to forecast when they will appear, and safely mitigate their removal. Frost on exterior of tower gas temps below 30 degrees farenheit clogge trays or packing in tower unusually loud noise partially plugged trays or packing high pressure or high velocity gas tower may be undersized dew points dew points above spec. Thermodynamic simulation of gas dehydration is difficult due to the interaction be. Hydrates are solid, icelike crystallized compounds formed of hydrocarbons and water.
On the other hand, soliddesiccant dehydration uses the principle of adsorption, with gas passing from top to bottom of a tower containing desiccant material. Absorption uses a dehydrating agent to remove water vapor from natural gas while adsorption condenses water vapor out of the gas. Gas dehydration 6 aalborg university esbjerg 1 introduction the offset for this report is the offshore oil and gas production in the danish sector in the north sea. Introduction the use of glycol to dehydrate gas streams is an established method that has proven its functionality and versatility over many years. These units can reduce the water content of a gas stream to less than 0. Water also can cause corrosion in the presence of acid gas component in natural gas. In this method the h 2o is adsorbed by solid desiccants, most often by mole sieve, silica gel or alumina. Poor dehydration requires further, more detailed investigation dew points below spec. Natural gas production and delivery process diagram. Lower water vapor content in high pressure natural gas also affects the size requirements of the equipment.
The solid desiccants commonly used for gas dehydration are those that can be regenerated and. Process temperatures inside the contactor rise above ambient temperature due to the exothermic heat of absorption and reaction, with a maximum temperature observed near. As an introduction, the book provides different concepts and theories that describe the gas processing industry. Shale gas and new fracking techniques are covered in detail. Farman abstract the purpose of this research is to study the dehydration process of natural gas by adsorption using molecular sieve as it is in the north gas. The theme of natural gas ng dehydration is closely linked with storage of natural gas. Without dehydration, a free water phase liquid water could also drop out of the natural gas as it is either cooled or the pressure is lowered through equipment and piping.
Design glycol units for maximum efficiency vincente n. The glycol dehydration process is an example of a process that provides absorption dehydration, and in the process, a liquid desiccant provides the means to absorb water from the gas stream. It discusses the various designs and operations in a gas processing facility. Natural gas dehydration is the process of removing associated water from natural gas molecules either by absorption or adsorption. Gas dehydration field manual presents different methods of gas dehydration, focusing on the differences between adsorption and absorption. With this in mind, national strategic reserves are created. Designed for engineers, technologists, and operations personnel involved in the design and operation of gas processing facilities, the book starts with an explanation of the terms and theories used. In addition to separating oil and some condensate from the wet gas stream, it is necessary to remove most of the associated water. Scribd is the worlds largest social reading and publishing site. Adsorption or solid bed dehydration is the process where a solid desiccant is used for the removal of water vapor from a gas stream. Natural gas dehydration 5 temperatures and the absorbed water is boiled out from teg during regeneration in a reboiler at high temperatures. Gas hydrates the dehydration of natural gas by any means is done primarily to prevent the formation of gas hydrates during the trans mission of natural gas.
The dehydration process is simplewet gas contacts dry glycol, and the glycol absorbs water from the gas. The dehydration unit of a plant that processes natural gas uses triethylene glycol teg as an absorbent to remove water from the gas to prevent blockages in pipes due to the formation of hydrates. In general, the faster the gas is moving, the bigger around the tower needs to be. Pdf natural gas dehydration using triethylene glycol teg.
Gasdry desiccants are applied throughout the natural gas industry, from the production field, to the processing plant, to storage, transmission, and distribution. Rarely covered in formal engineering courses, natural gas hydrates are a common problem and reallife danger for engineers worldwide. The gas dehydration school he teaches was developed over 20 years ago, through many hours of field experience. For the love of physics walter lewin may 16, 2011 duration. If the composition of co2 exceeded that limit it would freeze in the liquefaction process pipelines. Glycol dehydration process an overview sciencedirect. There are two basic reasons why ng storage is important. Analysis of natural gas prices and also developments in the natural gas sector. Passive dehydration system croft productions systems. Molecular sieve technology is widely used for the simultaneous removal of water and mercaptans from both gas and liquid feed streams. Pdf processing of natural gas sweeting, dehydration. It is usually produced saturated with water vapor under production conditions.
In order to achieve such speci cations, the raw gas must pass through a series of puri cation steps, which compose the socalled natural gas chain. Natural gas dehydration technologies natural gas must be dehydrated to remove water vapour. A triethylene glycolwater system analysis article pdf available in energy sources part a recovery utilization and environmental effects 3220. Water vapour causes the formation of hydrates, over saturation of natural gas, and corrosion of equipment. Glycol dehydration units depress the hydrate formation point of the gas through water removal. Lng dehydrationdrying of natural gas absorption and refrigeration with hydrate inhibition is the most common dehydration process used to meet pipeline sales specifications. Produced gas is saturated with water, which must be removed for gas transmission. In natural gas systems, removing water vapor reduces pipeline corrosion and eliminates line blockage caused by hydrate formation. Maurice stewart, ken arnold, in gas dehydration field manual, 2011. The specific focus of the report is gas dehydration and the processes involved. Betsy casada sunday, july 23, 2017 the presence of waterwater vapor in natural gas causes hydrates solid, icelike crystals of hydrocarbons and water that form under high pressure in well streams with a low temperature which in turn cause freezing and blocking of pipelines, valves and other equipment, effectively shutting. Meeting the challenges of glycol dehydration whitepaper. One of the most common methods for removing the water from produced gas is glycol. Several known vocs, volatile organic compounds, such as propane, benzene and formaldehyde occur in natural gas and are emitted from teg units.
Some physical properties of pure teg are given in the following text. This stage is directed more to co2 removal since the bolivian natural gas contains no sulfur in. Triethylene glycol teg is the most commonly used glycol in the dehydration process, and the glycol. The raw natural gas extracted from production wells contains many impurities that must be removed in order to achieve the speci cations of the liqui ed natural gas lng andor the pipeline gas. Using some recently executed projects, the major considerations andor optimizations will be explained.
Gas dehydration is widely used in natural gas treatment plant as a common process, because water and hydrocarbon can form hydrates ice formation which may block valve and pipelines. The source of the gas moved through the transmission lines may be producing wells or developed storage pools. Process used for dehydration of natural gas by absorption. It is the most common and economical means of water removal from these streams. Solutionstm glycol dehydration unit is a complete water vapor removal system used on natural gas well streams to meet typical pipeline and process specifications.
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