The present paper analyses sweetening technologies available to treat natural gas with a high carbon dioxide co 2 content, considering the integration of sweetening facilities with different gas. Sour natural gas compositions can vary over a wide concentration of h 2 s and co 2 and a wide concentration of hydrocarbon components. Pdf on mar 1, 2014, mateusz korpys and others published methods for sweetening natural and shale gas find, read and cite all the research you need on researchgate. Carbon dioxide and hydrogen sulfide removal from natural gas is a key step in the liquefied natural gas lng process, in particular for sour gas streams containing significant.
In all regenerative solvent systems, it is necessary to periodically add pure solvent to the solution because of the loss of solvent during operation. It was an oral presentation at ghgt12 in austin, texas, usa. Modelling the natural gas sweetening and dehydration prior to. Modelling of natural gas sweetening and dehydration prior. The gas sweetening process aims to remove part or all of the acid gas that the natural gas contains for different reasons as follows. Natural gas that contains sulfur is called sour gas because sulfur has a strong rotteneggs odor. Solvent losses in gas treating systems can occur because of. The co 2 level must be reduced according to the natural gas sales specification. Fundamentals of gas sweetening k, f, butwell l, kroop union carbide corporation tarrytown, new york natural gas has a wide range of acid gas concentrations, from parts per million to 50 volume percent and higher, depending on the nature of the rock formation from which it. Us4748011a method and apparatus for sweetening natural. Thus, sour gas or acid gas must be treated to remove these toxic components. Co2 from natural gas sweetening to kick start eor in. Recovery after extraction, raw natural gas must go through processing before it is suitable for industrial, commercial, and residential usage.
The present work comprises the modelling of natural gas ng purification prior to liquefaction. The present work comprises the modelling of natural gas ng purification prior to liquefaction, more precisely its sweetening and dehydration. To meet sales specifications and maintain efficient operations, natural gas goes through a sweetening process to remove contaminants. Modelling the natural gas sweetening and dehydration prior. Doctor test is qualitative test for detecting hydrogen sulfide and mercaptan sulfur in hydrocarbon liquids. Publishers pdf, also known as version of record includes final page. First, liquids can be stored and transported to the market more profitably than gas.
Gas sweetening is the process for the removal of mainly acid gases h 2 s and co 2 and, in addition, the simultaneous removal of sulphur organic species rsh, cos, cs 2 from process gas. Amines as gas sweetening agents henriette hansen, master thesis spring 2014 page 10 of 74 1. Typical contaminants in natural gas streams may be liquid hydrocarbons, salt water, sands, well treating compounds, pipeline treating chemicals, and compressor oils. Crude oil sweetening and stabilization aong website. Since ng exists in underground reservoirs it contains several impurities that must be removed in order to meet liquefied natural gas lng specifications, since they can cause corrosion, plugging and. Natural gas processing consists of separating first, all impurities found including acid gases, water vapor, and inert gases. In the transmission of natural gas further condensation of water is problematic. The processing of natural gas, in many respects, is less complicated than the processing of crude oil but is equally important to the end users. Sweetening of sour natural gas is the initial purification step which takes care of the removal of acid gases h2s and co2. For the purpose of these calculations a generic natural gas source is assumed with a high co 2 content of 10%. Pdf on mar 1, 2014, mateusz korpys and others published methods for sweetening natural and shale gas find, read and cite all the.
A method and apparatus are disclosed for sweetening of natural gas at the well head or at a common collection point from a number of wells, where, in the usual collection system for natural gas, the gas from one or more wells is collected through a collection line or manifold and often subjected to conventional treatments for dehydration andor separation of petroleum condensates. Gas sweetening is a process that has to be executed to remove hydrogen sulphide h2s from gasses. Simulation study of sweetening and dehydration of natural. Sour gas must be sweetened because h 2 s and co 2 have a corrosive effect on gas pipelines and are also toxic to humans. When natural wellhead or oil field associated gases are highly loaded with acid gases, the dilemma facing most operators is what to do, how and when to best. Gas sweetening is the process of removing hydrogen sulfides, carbon dioxide, and mercaptans from natural gas to make it suitable for transport and sale. The amine solution sweetens the natural gas by absorbing the c0 2 and h 2 s upon contact. The second case study examined and design sweetening process for natural gas stream with a moderate contents of acid gases which about 2500 ppm for h2s. A feed natural gas is introduced to the lumen side of the membrane contactor.
In this way, the sweetening of ng using diethanol amine dea was simulated in. Our expertise in sweetening processes includes multicomponent absorption of inorganic and organic sulphur species. Natural gas containing high quantities of h2s and co2 is considered toxic. If the composition of co2 exceeded that limit it would freeze in the liquefaction process pipelines. Pdf gas sweetening process subhasish mitra academia. Natural gas from a natural reservoir or associated to a crude production can contain acid gas h2s andor co2. The process can include providing a membrane contactor having a lumen side and a shell side. An exemplary embodiment can be a process for sweetening natural gas to liquefied natural gas specifications.
Introduction to the sweetening of natural gas with emphasis on sulfur recovery. For commercial natural gas, the maximum allowable co 2 level is 2. This stage is directed more to co2 removal since the bolivian natural gas contains no sulfur in. First, co2 and h2s removal stage which is constructed to assure that co2 would not exceed 50 ppm in the natural gas feed. It is a common unit process used in refineries, and is also used in petrochemical plants, natural gas processing. Two key passages are the sweetening removal of h 2s and co 2 and the dehydration processes. H2s is poisonous and if leakage occurs, people in the surroundings can be. Simulation study of sweetening and dehydration of natural gas. Removal of these acid gases is essential since their presence poses severe corrosion problem to the downstream process lines and. Aminebased gassweetening processes prove economically more viable than the benfield hipure process richard aochieng, abdallah s. All heat exchangers, air coolers, and centrifugal pumps are designed with at least a 10% capacity margin. The process is summarized in reaction 1 and illustrated in figure 5. Gas sweetening and processing field manual provides engineers with the ability to understand and select the most efficient and cost effective method to fit their individual needs. For safety reason, to remove the h2s content of the natural gas stream.
Amines as gas sweetening agents henriette hansen, master thesis spring 2014 page 3 of 74 abstract co 2 and h 2s are acid components present in natural gas recovered from wells in the underground. Basic terminology safety precautions gas specifications natural gas contaminants why sweetening the gas. Video sample from amine sweetening, overview and explanation of principles, supported with onsite viewing and clear graphics. Amine treatment, physical methods and others are discussed. 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. The sweet gas is removed overhead and the rich amine is drained and. Amine treating can be used in refineries, petrochemical plants, natural gas processing plants and other industries.
Aminebased gassweetening processes prove economically. This step will be explained in detail in the liquefaction section of this report. Amines as gas sweetening agents amines as gas sweetening. The train 3 gas sweetening plant is a benfield hipure design supplied by uop, and is a hybrid arrangement of the basic benfield and amine units5. It is a rigorous exposition of all natural gas sweetness processes. Pdf introduction to the sweetening of natural gas with. Water in natural gas can create problems during transportation and processing, of which the most severe is the formation of gas hydrates or ice that may block pipelines, process equipment, and instruments.
At present, the amine process also known as the girdler process, is the most widely used method for h2 s removal. The present paper analyses sweetening technologies available to treat natural gas with a high carbon dioxide co2 content, considering the integration of. In consultation with the customer, we select the most costeffective approach that also provides the right treatment performance for the particular makeup of the gas stream. Gas sweetening is a critical procedure in gas processing facilities. Us4748011a method and apparatus for sweetening natural gas. An absorption solvent is introduced to the shell side of the membrane contactor. The process involves an amine gas con tactor that typically operates at pressure up to 1200 psi 83 bar, and an amine. Amines as gas sweetening agents amines as gas sweetening agents. Reviews of the gas sweetening and processing field manual. If not removed from the gas they are a cause of corrosion in equipment.
The exercises appear at the conclusion of each chapter. The actual process used to separate oil from natural gas, as well as the equipment that is used, can vary widely. Co 2 from natural gas sweetening to kick start eor in the north sea. Corrosion of materials in contact with natural gas and condensed water is also a common problem in the oil and gas industry. Gas sweetening is one of the important purification processes which is employed to remove acidic contaminants from natural gases. Natural gas sweetening using ionic liquids technische universiteit. Gas sweetening processes chemical processes hot potassium. A sweetening plant using mdea is employed to reduce the co 2 content of the. The processes used for removal of acid gas are referred to as sour gas sweetening, amine gas sweetening. These impurities need to be removed to different levels to meet each clients specific process requirements.
It is an essential step of sour gas processing for natural gas treatment, ngl recovery. Modelling of natural gas sweetening and dehydration processes. Gas sweetening and processing field manual sciencedirect. The removal of h 2 s from sour gas is called sweetening.
Amine gas sweetening is an energy intensive process commonly used to remove hydrogen sulfide and carbon dioxide from natural gas streams. It can increase pressure drop in the line and often leads to corrosion problems. H 2s is corrosive and is damaging the pipe systems and equipment when present. Sour gas is natural gas or any other gas containing significant amounts of hydrogen sulfide h 2 s natural gas is usually considered sour if there are more than 5. Sebastine2 1school of chemical and petroleum engineering, koya university, kurdistan regioniraq 2school of science and engineering, teesside university, uk abstract natural gas is the most important and. Sulfur in natural gas occurs as hydrogen sulfide, which must be removed because it. In the case of sweetening, the most common process technique. It is important that these contaminants be removed before the gas reaches the absorber.
It features tips for diagnosing and solving equipment and pdf process problems. If the h 2 s content exceeds the sales gas specification limit, the excess h 2 s must be separated from the sour gas. Enerflex provides the full suite of sour gas sweetening approaches, including amine and glycolbased systems. Schlumberger designs and manufactures a variety of gas sweetening systems, including amine systems, to remove hydrogen sulfide h2s, carbon dioxide co2, mercaptans, and other contaminants from natural gas streams. It includes equipment and process troubleshooting techniques. In most sour gas sweetening installations, a corrosion inhibitor is continuously injected into the sweetening solution.
Aminebased gas sweetening processes prove economically more viable than the benfield hipure process richard aochieng, abdallah s. Second, it is advantageous to minimize gas losses from light crude oil when stored. Moreover, in this simulation work, meg mono ethylene glycol was selected as an absorbent for the gas sweetening process. Amine gas treating, also known as amine scrubbing, gas sweetening and acid gas removal, refers to a group of processes that use aqueous solutions of various alkylamines commonly referred to simply as amines to remove hydrogen sulfide h 2 s and carbon dioxide co 2 from gases. Aminebased gassweetening processes prove economically more.
Gas sweetening introduction carbon dioxide co2 and hydrogen sulphide h2s are common impurities in natural gas. Two key passages are the sweetening removal of h2s. Natural gas sweetening process simulation and optimization. The most common methods for removal of co2 andor h2s from the gas is via amines, physical solvents, membranes or. Sweetening of natural gas free download as powerpoint presentation. The process involves an amine gas con tactor that typically operates at pressure up to 1200 psi 83 bar, and an amine regenerator that operates at near atmospheric pressure. Gas sweetening and processing field manual 1st edition. Petersa, justin slagleb adepartment of chemical engineering, petroleum institute, p. Gas sweetening is sometimes referred to as amine treating.
A third safety step is taken in the liquefaction process where molecules of water, which accompany the natural gas in the feed, are condensed and flashed in the stage of natural gas precooling. Pdf methods for sweetening natural and shale gas researchgate. Sweetening of natural gas gases chemical process engineering. Untreated natural gas containing carbon dioxide c0 2 and hydrogen sulfide h 2 s flows into the bottom of the amine contactor where it contacts countercurrent flowing aminewater from the top of the tower. Improved performance of the naturalgassweetening benfield. Fundamentals of gas sweetening k, f, butwell l, kroop union carbide corporation tarrytown, new york natural gas has a wide range of acid gas concentrations, from parts per million to 50 volume percent and higher, depending on the nature of the rock formation from which it comes. In the case of sweetening, the most common process technique involves an aqueous solution of alkanolamines as absorbing solvent. However, this threshold varies by country, state, or even agency or application. The process of removing sulfur from natural gas is therefore called sweetening. If h2s and co2 volumes are appreciable, this lowers the heating value of the sales gas. The economic value of the crude oil is accordingly influenced by stabilization. Co from natural gas sweetening to kick start eor in the. Therefore, this study aims to simulate the gas sweetening process by using the aspen hysys v.
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