Natural gas liquids recovery

New Mexico s San Juan Gas Plant is one of the United States newest and largest natural gas liquids recovery plant. Commissioned in November 1986, its levels of productivity are high by industry standards. Located near Bloomfield, New Mexico, just south of tlie Colorado border, the plant is jointly owned by Conoco Inc. (then a subsidiary of the DuPont Company) and Tenneco Inc., both of Houston. It is operated by Conoco and is named after its location in the San Juan basin, an area of oil, gas, and coal production. 

Condensation principle, 76 65 Condensation processes, natural gas liquid recovery by, 72 375 Condensation reactions... 

No discussion of natural gas liquids recovery would be complete without some reference to the conservation problems involved. Formerly considerable volumes of oil well gas were flared without processing. The liquid content of this rich gas was lost entirely. 

Long, N.V.D. and Lee, M. (2012b) Improvement of natural gas liquid recovery energy efficiency through thermally coupled distillation arrangement. Asia-Pacific Journal of Chemical Engineering, 7, 71-77. 

This type of column is found in the light ends section of the refinery gas plant and processes only identifiable components. It is also the common type of fractionator found in the distillation section of natural gas liquids recovery facilities or, for that matter, in most chemical plants where the process objective is to make a separation between two components. The design procedure for calculating this type of tower is outlined in the following discussion. 

When gases are rich in ethane, propane, butane and heavier hydrocarbons and there is a local market for such products it may be economic to recover these condensable components. Natural gas liquids can be recovered in a number of ways, some of which have already been described in the previous section. However to maximise recovery of the individual NGL components, gas would have to be processed in a fractionation plant. 

Ethane is used by petrochemical plants to make ethylene, a primary building block for many plastic products. Butane and condensate are used by refineries producing automotive fuel. For production of NGL s (natural gas liquids), die plant s recovery rate of 98% of ediane and 100% of all odier liquid products contained in natural gas, is among die best in die world. 

Process for Recovery of Natural Gas Liquids From a Sweetened Natural Gas Stream, U.S. Patent 4,421.535, Dec. 20, 1983. 

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 definitions above are an abbreviated version of those used in a veiy complex and financially significant exercise with the ultimate goal of estimating resei ves and generating production forecasts in the petroleum industry. Deterministic estimates are derived largely from pore volume calculations to determine volumes of either oil nr gas in-place (OIP, GIP). This volume when multiplied by a recovery factor gives a recoverable quantity of oil or natural gas liquids—commonly oil in standard barrels or natural gas in standard cubic feet at surface conditions. Many prefer to use barrels of oil equivalency (BOE) or total hydrocarbons tor the sum of natural gas, natural gas liquids (NGL), and oil. For comparison purposes 6,000 cubic feet of gas is considered to be equivalent to one standard barrel on a British thermal unit (Btu) basis (42 U.S. gallons). 

Natural gas liquids may contain significant amounts of cyclohexane, a precursor for nylon 6 (Chapter 10). Recovery of cyclohexane from NGL hy conventional distillation is difficult and not economical because heptane isomers are also present which hoil at temperatures nearly identical to that of cyclohexane. An extractive distillation process has been recently developed by Phillips Petroleum Co. to separate cyclohexane. ... 

After the recovery of natural gas liquids, sweet dry natural gas may be liquefied for transportation through cryogenic tankers. Further treatment may be required to reduce the water vapor below 10 ppm and carbon dioxide and hydrogen sulfide to less than 100 and 50 ppm, respectively. 

Mehra (2) [Named after the inventor] A gas separation process utilizing absorption in a solvent at moderate pressures. Developed by Advanced Extraction Technologies and applied to hydrogen recovery, nitrogen rejection, and recovery of natural gas liquids. 

While the recovery processes used in extracting natural gas liquids from our gas production have improved enormously in the past 25 years, there has really been no new fundamental development in this period. Use of higher pressures and lower temperatures has permitted higher levels of recovery. Thus in today s technology recovery of 70 to 80% of the propane contained in the gas is a common attainment and higher recoveries are known. Similarly, 95% of the butanes may be readily recovered as liquid and substantially 100% of the pentanes and heavier volatiles. 

Adjusted for Possible Increased Recovery of Natural Gas Liquids (Table V) ... 

Domestic petroleum, natural gas, and natural gas liquids production has declined at a rate commensurate with the decrease in reserves (see Table 2). Consequently, the reserves/production ratio, expressed in years, remained relatively constant from about 1970 through 1992, at 9—11 years (16). Much of the production in the early 1990s is the result of enhanced oil recovery techniques water flooding, steam flooding, C02 injection, and natural gas reinjection. 

The market value of natural gas liquids is highly volatile and historically has been weakly related to the world price of cmde oil. During the 1980s, the market value of natural gas liquids ranged from approximately 60% of the price of cmde to 73% (12). In this 10-year interval, several fluctuations occurred in the natural gas liquid market. Because of the variability of the natural gas liquid market, the NGL recovery plants need to have flexibility. Natural gas liquid products compete in the following markets ethane propane a liquefied petroleum gas (LPG) a C-3/C-4 mix and -butane all compete as petrochemical feedstocks. Propane and LPG are also used as industrial and domestic fuels, whereas 2-butane and natural gasoline, consisting of C-5 and heavier hydrocarbons, are used as refinery feedstocks. 

The total U.S. recovery of natural gas liquids is about 30-35 barrels per million cubic feet of marketed natural gas. The total NGL supply is supplemented by about 200-250 million barrels per year of refinery production, which equates to about 5 percent of the total crude oil charge to refineries. Some of the petrochemical products produced from natural gas and NGLs are shown in Fig. 20.5. 

Combining refrigeration with oil absorption allowed for additional liquid recoveries and greater economy of operation. Using temperatures as low as -40°F (-40°C), refrigerated oil absorption plants were capable of recovering 70 percent or more of the propane present in the natural gas stream. Recoveries of the butane and heavier constituents were essentially 100 percent. 

Recovery of natural-gas liquids (NGL) from natural gas is quite common in natural gas processing. Recovery is usually done to ... 

The main purpose of Natural Gas Liquid (NGL) recoveiy unit is to separate out propane plus component from treated feed gas using ORTLOFF-SCORE (Single Column Overhead Recycle) process. The NGL Recovery Unit is designed to recover more than 96.8% of the available propane and almost 100% of the C4+ and heavier hydrocarbons when processing at the design flow rates of 1580Knm3/hr. 

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