Gas processing plant

The gas processing options described in the previous section were designed primarily to meet on-site usage or evacuation specifications. Before delivery to the customer further processing would normally be carried out at dedicated gas processing plants, which may receive gas from many different gas and oil fields. Gas piped to such plants is normally treated to prevent liquid drop out under pipeline conditions (dew point control) but may still contain considerable volumes of natural gas liquids (NGL) and also contaminants. 

Other natural gas Hquids include natural gasoline [8006-61 -9] which is composed of the pentanes and heavier components of the natural gas stream, and ethane [74-84-0]. Most recendy ethane has become the principal product of natural gas processing plants. 

Design and Construction ofiEP-Gas Installations at Marine Terminals, Natural Gas Processing Plants, Refineries, Petrochemical Plants, and Tank Farms, API Standard 2510, 4th ed., American Petroleum Institute, Washington, D.C., Dec. 1978. 

Equipment Leaks of VOG from Onshore Natural Gas Processing Plants... 

For many years, turboexpanders have been used in cryogenic processing plants to provide low-temperature refrigeration. Power recovery has been of secondary importance. Expander efficiency determines the amount of refrigeration produced and, in gas process plants, the amount of product usually depends on the available refrigeration. Accordingly, there is a large premium on efficiency and, of course, on reliability. 

As stated earlier, turboexpanders are normally used in cryogenic processes to produce isentropic expansion to cool down the process gas. Two common applications are natural gas processing plants and chemical plants. In natural gas processing plants, turboexpanders are installed to liquify heavier hydrocarbon components and produce lean natural gas with specified dew point limits to meet required standards. 

Figure 6-14. Process flow diagram of a typical natural gas processing plant.

The total cost of the 100 losses is 7.52 billion in 1997 dollars, The largest loss was 252,500,000, from a vapor cloud explosion at a gas processing plant at Cactus, Mexico. The average loss was 75,800,000. 

Single losses were most costly at refineries than in any other type of plant at an average loss of 73.700,000, The second most costly accidents occurred at petrochemical plants w iih an avciagc loss of 80,800,000. Although only 1% of the losses occurred at gas processing plants, the hiahest (vcrage loss was 117,800,000. 

Ethylene glycol is the most common recoverable inhibitor. It is less soluble in hydrocarbons and has less vaporization loss than methanol. This is common on the inlet to gas processing plants. 

A gas-processing plant, as described in Chapter 9, is designed to recover ethane, propane, butane, and other natural gas liquids from the gas stream. A condensate stabilizer also recovers some portion of these liquids. The colder the temperature of the gas leaving the overhead condenser in a reflux stabilizer, or the colder the feed stream in a cold-feed stabilizer, and the higher the pressure in the tower, the greater the recovery of these components as liquids. Indeed, any stabilization process that leads to recovery of more molecules in the final liquid product is removing those molecules from the gas stream. In this sense, a stabilizer may be considered as a simple form of a gas-processing plant. 

The first step in a gas processing plant is to separate the components that are to be recovered from the gas into an NGL stream. It may then be desirable to fractionate the NGL stream into various liquefied petroleum gas (LPG) components of ethane, propane, iso-butane, or normal-butane. The LPG products are defined by their vapor pressure and must meet certain criteria as shown in Table 9-1. The unfractionated natural gas liquids product (NGL) is defined by the properties in Table 9-2. NGL is made up principally of pentanes and heavier hydrocarbons although it may contain some butanes and very small amounts of propane. It cannot contain heavy components that boil at more than 375°F. 

In most instances gas processing plants are installed because it is more economical to extract and sell the liquid products even though this lowers the heating value of gas. The value of the increased volume of liquids sales may be significantly higher than the loss in gas sales revenue because of a decrease in heating value of the gas. 

This chapter briefly describes the basic processes used to separate LPG and NGL liquids from the gas and to fractionate them into their various components. It is beyond the scope of this text to discuss detailed design of gas processing plants. 

A gas processing plant selectively extracts ethylene and ethane from an incoming natural gas mixture stream. These two light hydrocarbons are absorbed in a heavy gasoline type absorber oil, and then stripped with open steam in an open tower. The system data are (see Figure 8-41) ... 

NGL are those portions of natural gas which are recovered as liquids in separators, field facilities or gas processing plants. Natural gas liquids include, but are not limited to, heavier hydrocarbon components, natural gasoline and condensate they may include small quantities of nonhydrocarbons. 

Natural Gas Processing Plants, Refineries, Petrochemical Plants, and Tank Farms. Washington, D.C. 

Mahoney (1997) has analysed the 170 largest losses in refineries, petrochemical plants and gas processing plants from 1966 to 1996. Nearly all the losses in the analysis involved fires or explosions. Most common primary cause of losses was piping. Instone (1989) analysed some 2000 large loss claims of hydrocarbon industry at Cigna Insurance. Table 20 lists the ISBL equipment and Table 21 lists the data of the OSBL equipment by Mahoney (1992, 1997) and Instone (1989). 

Natural Gas Liquids (NGL) - The portions of natural gas that are liquefied at the surface in production separators, field facilities, or gas processing plants, leaving dry natural gas. They include but are not limited to ethane, propane, butane, natural gasoline, and condensate. 

The problems associated with new synthesis gas processes are far greater than problems associated with gas processing plants or refineries because of water, salt, sludge, ammonia, and cresols present in the process streams. This paper attempts to identify the magnitude of the problems and methods for solving these problems. The problem of predicting the thermodynamic properties of nonpolar-polar mixtures by means of equations of state is also identified as an area needing study. 

Clark, P.D., Dowling, N.I., Hyne, J.B., Moon, D.L. 1995. Production of hydrogen and sulfur from hydrogen sulfide in refineries and gas processing plants. Alberta Sulphur Res Quart Bull 32 11-28. 

Uses Solvent recovery and extraction blowing agent for plastic foams low temperature thermometers natural gas processing plants production of olefin, hydrogen, ammonia fuel production pesticide manufacture of artificial ice organic synthesis. 

Steam Line Rupture at Tennessee Eastman Division, Peter N. Lodal Lessons Learned from the Longford Royal Commission Investigation into the Explosion and Fire on 25 September 1998 at the Esso Gas Processing Plant, Mark Boult Gary Kenney, Robin Pitblado... 

In 1978, U. S. recovered sulfur production and shipments were balanced at 4.1 MM metric tons each (11). Year end capacity has been estimated at 6.2 MMLT and 6.4 MMLT for 1980 and 1985, respectively (12, 13). Assignable daily capacity at year end 1978 was 9,132 metric tons for refineries, 5,464 metric tons for natural gas processing plants, and 1,682 metric tons from H2S and acid gas... 

Natural Gas Processing. In 1978, based on a 330 day operating year, sulfur output from natural gas processing plants was estimated at 276,000 LT in district I 30,000 LT in district II ... 

Di-isopropanol-amine (DIPA) is used to remove hydrogen sulfide from natural gas supplies (Goar, 1971). Unfortunately, this compound has been found as a groundwater contaminant at a total concentration of about 1 mM levels near such a sour gas processing plant. Consider an aquifer with the following characteristics ... 

Transport of Di-Isopropanol-Amine (DIPA) in Groundwater from a Sour Gas Processing Plant... 

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