Refining distillation process

Polyolefin plastics are essentially polymers that are composed out of hydrocarbon molecules. These are typically obtained from fossil fuel that is, petroleum. After a relatively simple heat treatment in a refining (distillation) process, specific distillate fractions, being hydrocarbon... 

Solvent Refined Coal Process. Work ia the mid-1960s by the Speacer Chemical Co. (9) and dating the 1970s by the Gulf Chemical Corp. led to two solvent refined coal (SRC) processiag schemes SRC-I for productioa of low ash soHd boiler fuels and SRC-II for distillates, eg, "syn-cmde."... 

Petroleum refining Primary distillation process Sludges containing hydrocarbons... 

The crude source has a definite effect on the composition of the refined product. A schematic illustrating the distillation process is shown in Figure 4.5. These products correspond to their respective boiling points, carbon ranges, and analytical method as illustrated in Figure 4.6. 

Refining the process(es) by which petroleum is distilled and/or converted by application of a physical and chemical processes to form a variety of products are generated. 

The ability of water to function as a solvent for many compounds also makes it useful in the fuel refining and processing industry. It is utilized to wash and remove salts from crude oil prior to distillation, remove H2S and mercaptans from processed fuel (as caustic water), and function in the removal of trace amounts of acid from acid-catalyzed fuel processing reactions. 

Crude oil typically contains little to no olefinic compounds. Through refining and processing, however, olefins are produced and become a part of various crude oil fractions. Olefins can be found in thermally cracked and catalytically cracked gasoline fractions as well as in FCC cycle oils and coker gas oils. For this reason, it is not unusual for finished gasoline and distillate blends to contain a high-olefin-content stream. 

Bitumen describes a black or dark brown masticlike material that is thermoplastic in nature and softens upon heating. The sources of bitumen are petroleum or coal deposits. The natural product is commonly called gilsonite or pitch, a mineral formed by an old weathered petroleum flow at the surface of the earth that has left behind the larger molecules from the petroleum. A principal source in the past has been Lake Trinidad, a 445,000 m2 deposit on the island of Trinidad. Bitumen from petroleum or crude oil is called asphalt (qv). It is the material left behind after all the valuable compounds, eg, gasolines, have been distilled out of the cmde oil. The amount and quality of asphalt is dependent on the source of the crude oil used in the refining process. Some cmde oils have a higher content of asphaltic bitumen left after the distillation process. Bitumen from coal is coal-tar pitch. It remains after the valuable coal oils and tars have been distilled out of the coal tars produced by distractive distillation. Most industrial applications for bitumen products use asphalt or coal-tar pitch because the supply is more uniform and plentiful. 

Solvent-Refined Coal Process. In the 1920s the anthracene oil fraction recovered from pyrolysis, or coking, of coal was utilized to extract 35—40% of bituminous coals at low pressures for the purpose of manufacturing low cost newspaper inks (113). Tetralin was found to have higher solvent power for coals, and the I. G. Farben Pott-Broche process (114) was developed, wherein a mixture of cresol and tetralin was used to dissolve ca 75% of brown coals at 13.8 MPa (2000 psi) and 427°C. The extract was filtered, and the filtrate vacuum distilled. The overhead was distilled a second time at atmospheric pressure to separate solvent, which was recycled to extraction, and a heavier liquid, which was sent to hydrogenation. The bottoms product from vacuum distillation, or solvent-extracted coal, was carbonized to produce electrode carbon. Filter cake from the filters was coked in rotary kilns for tar and oil recovery. A variety of liquid products were obtained from the solvent extraction-hydrogenation system (113). A similar process was employed in Japan during Wodd War II to produce electrode coke, asphalt (qv), and carbonized fuel briquettes (115). 

In short, distillation is, at best, looked upon as a means by which the lower-boiling fractions can be separated from a feedstock prior to being subjected to a suitable conversion (or refining) method. It is, in fact, the means by which the undesirable higher molecular weight materials are removed from the feedstock as atmospheric or vacuum residua. It would, indeed, be a very rare occasion if the distillation process actually served as an efficient means of desulfurization rather than a concentration process. 

Refining conventional feedstocks presumes that the distillation is the first pretreatment process applied to a feedstock. Application of distillation as a separation to heavy feedstocks is a moot point, often being considered economically unnecessary and of little benefit to the refining scenario. Processes that receive consideration to separate the residuum include deasphalting as well as thermal treatment. These options have not been accepted for wide use because of increased cost or because they recover low-value portions of the feedstock that must be used or disposed of at some stage of the refining operation. Nevertheless, some consideration is worthy of note here because of the potential for such concepts in the future. 

In order to satisfy the changing pattern of product demand, significant investments in refining conversion processes will be necessary to profitably utilize the heavy oils and residua. The most efficient and economical solution to this problem will depend to a large extent on individual refinery situations. However, the most promising technologies will likely focus on the conversion of vacuum residua and extra-heavy crude oils into useful low-boiling and middle distillate products. 

The lighter distillates and naphtha from oil shale and coal can be refined by processes used for petroleum, except that more severe hydrotreatment will be required to remove nitrogen and the other nonhydrocarbon impurities that poison catalysts and cause product instabiltiy. 

Distillation processes exploit the low volatility of cholesterol compared to the major triacylglycerols of milk fat for removal of cholesterol. Vacuum and short-path molecular distillation processes can efficiently remove cholesterol but it may be achieved at the expense of removing some low-molecular weight triacylglycerols and flavor components of the milk fat. Vacuum steam distillation is commonly used for refining fats and can also be used to refine milk fat. Cholesterol-reduced milk fat, which was produced by steam distillation, has been used successfully to formulate butter, cream and ice cream (Schroder and Baer, 1991, Elling et al., 1995, 1996). If the flavor of milk fat is to be preserved, the flavors can be trapped and re-incorporated into the milk fat that has been stripped of cholesterol (Boudreau and Arul, 1993). 

Catacol A catalytic distillation process for petroleum refining, offered by Axens. 

The details of glycerine refining via the Crown Iron Works Co. process, which is representative of the continuous distillation process used by a large portion of suppliers for soap lye crude glycerine, are detailed here (Figure 6). 

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