Even now, gas production is gaining market share as liquefied natural gas lng provides an economical way. Glycol dehydration troubleshooting guide oil and gas. Comparison of natural gas dehydration methods 1,2 general overview of applicability of each dehydration method is shown in figure below. First, co2 and h2s removal stage which is constructed to assure that co2 would not exceed 50 ppm in the natural gas feed. When i read several literatures related to natural gas dehydration, the. However, natural gas found at the wellhead, although still composed. Comparison of methods for dehydration of natural gas stored in. Glycol dehydration cannot get to these low water levels mole sieves used for this. Water also can cause corrosion in the presence of acid gas component in natural gas. A great deal of the vapor and liquid that is caught up in the natural gas. It is one of the cleanest, safest and most useful of all energy. Contents vii disadvantages 43 plunger pumps 43 advantages 43 disadvantages 43 comparisonofhydrate prevention methods 43 overview 43 heaters 44 chemical injection 44 downholeregulators 44 summaryof hydrate prevention methods 45 hydrateinhibition 45 hammerschmidt equation 45 determinationoftotal inhibitor required 47 procedurefor. Dehydration is the process by which water is removed from natural gas.
Glycols typically seen in industry include triethylene glycol teg, diethylene glycol deg, ethylene glycol meg, and tetraethylene glycol treg. The equipment that extracts this liquid gold is expensive and sensitive to liquids. Natural gas phase behavior the natural gas phase behavior is a plot of pressure vs temperature thatdetermines whether the natural gas stream at a given pressure andtemperature consists of a single gas phase or two phases. Gas dehydration field manual defines the various methods of gas dehydration and discusses the differences between adsorption and absorption. This course will give you a basic understanding of the operation of a glycol dehydration system. Poor dehydration requires further, more detailed investigation dew points below spec. Pdf on oct 31, 2012, michal netusil and others published natural gas dehydration find, read and cite. Several natural gas dehydration methods and range of. The natural gas used by consumers is composed almost entirely of methane. Delta gas plant dehydration process using the hysys simulator. If there is only a small amount of water present, then the formation of hydrate is less. The theme of natural gas ng dehydration is closely linked with storage of natural gas.
It is the most common and economical means of water removal from these streams. This site is like a library, use search box in the widget to get ebook that you want. 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. Glycol dehydration is a liquid desiccant system for the removal of water from natural gas and natural gas liquids ngl. Dehydration of natural gas is the removal of the water that is associated with natural gases in vapor form. Principles and practices kindle edition by mokhatab, saeid, poe, william a. If there is no water present, then it is impossible for a hydrate to form. Lng dehydrationdrying of natural gas absorption and refrigeration with hydrate inhibition is the most common dehydration process used to meet pipeline sales specifications. At the same time, the petrochemical industry with its new plastic materials quickly increased production.
It can increase pressure drop in the line and often leads to corrosion problems. The dominant components of the natural gas, particularly methane, have the ability to form hydrates if the temperature and pressure allows hydrates to form. Natural gas dehydration lessons learned from the natural gas star program conocophillips the colorado oil and gas association, and the independent petroleum association of mountain states producers technology transfer workshop durango, colorado september, 2007 epa. Water content of natural gas 9 gpsa engineering data book, th ed. 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. Optimization of natural gas dehydration using triethylene glycol was carried out using aspen hysys process software and regression analysis. The sample calculations, equations and spreadsheets presented herein were developed using examples published in the engineering data book as published by gpsa as a service to the gas processing industry.
Natural gas hydrate download ebook pdf, epub, tuebl, mobi. 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. This stage is directed more to co2 removal since the bolivian natural gas contains. Thanks to the recent shale boom in north america, natural gas is in a surplus and quickly becoming a major international commodity. Natural gas is considered the dominant worldwide bridge between fossil fuels of today and future resources of tomorrow. The water content of the gas can be calculated using the. Use features like bookmarks, note taking and highlighting while reading handbook of natural gas transmission and processing. The phase behavior for natural gas with a given composition is typicallydisplayed on a phase diagram, an. As an introduction, the book provides different concepts and theories that describe the gas processing industry. This is a common method used for preventing hydrate formation. Dehydration is necessary to ensure smooth operation of gas transmission lines prevents the formation of gas hydrates and reduces corrosion.
All raw natural gas is fully saturated with water vapor when produced from an underground reservoir. When other hydrocarbons are present, the natural gas is wet. General selection chart of natural gas dehydration method 1, with modification bonus. Optimization of natural gas dehydration using triethylene. Introduction natural gas is a combustible mixture of hydrocarbon gases and a vital component of the worlds supply of energy. Gas dehydration field manual ebook by maurice stewart. Known for being highly flammable, gas hydrates are a preventable threat that can costs millions of dollars in. Two subsea natural gas treatment processes, namely natural gas dehydration and acid gas removal, are discussed in details with respect to the advantages and challenges in the implementation of. Rarely covered in formal engineering courses, natural gas hydrates are a common problem and reallife danger for engineers worldwide. The petroleum industry spends millions of dollars every year to combat the formation of hydratesthe solid, crystalline compounds that form from water and small moleculesthat cause problems by plugging transmission lines and damaging equipment. Liquid desiccants have found an extremely wide use for the dehydration of natural gas, and the bulk of this discussion will be centered upon glycols as utilized in gas dehydration. The natural gas industry has recognized that dehydration is necessary to ensure smooth operation of gas transmission lines.
In the transmission of natural gas further condensation of water is problematic. A recent epa survey determined that almost 36,000 glycol dehydration units are operating in the united states. Final report novel membranes for natural gas dehydration. There are two basic reasons why ng storage is important. Tegi t i b ti tteg is most common in absorption systems meg is most common in glycol injection systems. Glycol dehydration is a key component of the overall process that cant be skipped over. 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. 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. With all units optimally specified during the process, the lean teg inflow rate was varied with the water content in. The existing methods for gas dehydration in the field fall.
One of the problems with some of this natural gas is that it is in remote areas where there is little or no local use for the gas. With this in mind, national strategic reserves are created. Glycol dehydrators, part of natural gas dehydration systems, remove water vapor from gas streams to prevent the formulation of hydrates and corrosion in pipelines. Natural gas is considered dry when it is almost pure methane, having had most of the other commonly associated hydrocarbons removed. Modelling of natural gas sweetening and dehydration processes. All information and calculation formulae has been compiled and edited in cooperation with the gpa midstream association. Calcium chloride is often mentioned as a desiccant. Design glycol units for maximum efficiency vincente n. The glycol dehydration unit is a reliable, efficient system for removing water from natural gas well streams in order to meet typical pipeline and process. Nearly 50 percent worldwide natural gas reserves of 6,254. It is said to be applicable if water removal demand is not too big and the plant is on the low capacity side.
Gas dehydration chapter 11 based on presentation by prof. The idea of storing natural gas ng is to straighten demand and be. Handbook of natural gas transmission and processing. If the composition of co2 exceeded that limit it would freeze in the liquefaction process pipelines. Dehydration of natural gas is needed to remove the water that is associated with natural gases in vapor form. S natural gas reserves totaling 239 tcf, as stranded gas 1 2. Water vapour needs to be removed from natural gas streams to meet gas specifications and to avoid corrosion and hydrate formation in process equipment and pipelines. Although dehydration historically has been a fairly inexpensive step in the upgrading of natural gas to pipeline quality, costs are increasing. 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. When large gas volumes are transported, dehydration is the most efficient and economical means of preventing the hydrate formation in the trunk pipeline.
Secondly, ng storage enables the maximum capacity of distribution lines to be exploited. This paper compares three methods for natural gas dehydration that are widely. Unless gases are dehydrated, liquid water may condense in pipelines and accumulate at low points along. Click download or read online button to get natural gas hydrate book now. This treatment consists of dehydrating the natural gas, which is accomplished by lowering the dew point temperature of the gas at which water vapor will. 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. For the same inlet data, emah 11 performed simulations of a natural gas dehydration process in aspen hysys and aspen plus using different equilibrium models in order to. Comparison of three methods for natural gas dehydration. More than 90 percent of these systems 34,000 treat natural gas at flow rates averaging less than 10 mmscfd, the range in which a membrane process is more cost effective than glycol dehydration. One of the most common methods for removing the water from produced gas is glycol. Gas dehydration field manual presents different methods of gas dehydration, focusing on the differences between adsorption and absorption. It discusses the various designs and operations in a gas processing facility.
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