Naphtha, production volume

As can be seen, there is a small portion of ethylene produced in the gas. This small amount of olefin was sufficient for the early days of the chemical industry but soon became displaced by the larger production volume of olefins by steam cracking of ethane, LPG and naphtha from oil and gas sources. 

Richard Hale uses the following solvent —Amyl-acetate, 4 volumes petroleum naphtha, 4 volumes methyl-alcohol, 2 volumes pyroxyline, 4 to 5 ounces to the gallon of solvent. Hale used petroleum naphtha to hasten the drying qualities of the varnish, so that it would set on the article to be varnished before it had a chance to mn off. It is, however, the non-hygroscopic character of the solvent that makes the varnish successful. This formula is very largely used for the production of pyroxyline varnish, which is used for varnishing pens, pencils, c., also brass-work and silver-ware. 

Ratio of reaction volume (cu ft) to charge rate (thousand bbl per day) Per-centjigc increase in capacity Maximum naphtha production Quality operation ... 

Isomerization is a small-volume but important refinery process. Like alkylation, it is acid catalyzed and intended to produce highly-branched hydrocarbon mixtures. The low octane C5/C6 fraction obtained from natural gasoline or from a light naphtha fraction may be isomerized to a high octane product. 

Another nonsynthetic source for cyclohexane is natural gasoline and petroleum naphtha. However, only a small amount is obtained from this source. The 1994 U.S. production of cyclohexane was approximately 2.1 billion pounds (the 45th highest chemical volume). 

A plot of boiling temperatures (°F) vs. cumulative percent volume removed from the sample is referred to as a distillation curve. The boiling temperatures for various products range from high to low divided into the following product types residue, heavy gas-oil, light gas-oil, kerosene, naphtha, gasoline, and butanes (Table 4.4). 

The data from the density (specific gravity) test method (ASTM D1298 IP 160) provides a means of identification of a grade of naphtha but is not a guarantee of composition and can only be used to indicate evaluate product composition or quality when used in conjunction with the data from other test methods. Density data are used primarily to convert naphtha volume to a weight basis, a requirement in many of the industries concerned. For the necessary temperature corrections and also for volume corrections, the appropriate sections of the petroleum measurement tables (ASTM D1250 IP 200) are used. 

Petroleum crude and its refinery products have two major component based on distillation. The portion that can be distilled under refinery conditions can be called volatiles and the nondistillables are the nonvolatiles. The volatiles can be analyzed by GC or GC-MS. The crude has both components. The distillate as the names applied, such as naphtha and kerosene contain only volatiles. When GPC is used for analyzing various distillates, the fractions separated by GPC can be characterized by GC or GC-MS. These data can be used to verify the nature of components present in various distillation cuts as a function of GPC elution volume. If the samples such as crude contains both volatiles as well as nonvolatiles, the samples should be separated into volatiles and nonvolatiles. The GPC of both components should be used to calibrate the GPC of the total crude. The parameter that can be obtained from GPC is effective molecular length. It can be used to relate other molecular parameters of interest after calibration. 

In view of these considerations, a large amount of effort is reported in the scientific press on the development of a process to produce benzene from n-hexane by combined cyclization and dehydrogenation. w-Hexane has a low Research octane number of only 24.8 and can be separated in fair purities from virgin naphthas by simple distillation. Recently, an announcement was made of a process in the laboratory stage for aromatiza-tion of n-hexane (16). The process utilizes a chromia-alumina catalyst at 900° F., atmospheric pressure, and a liquid space velocity of about one volume of liquid per volume of catalyst per hour. The liquid product contains about 36% benzene with 64% of hexane plus olefin. The catalyst was shown to be regenerable with a mixture of air and nitrogen. The tests were made on a unit of the fixed-bed type, but it was indicated that the fluid technique probably could be used. If commercial application of this or similar processes can be achieved economically, it could be of immense help in relieving the benzene short-age. 

Figure 1.5 shows ways of designing tubular reactors to include heat transfer. If the amount of heat to be transferred is large, then the ratio of heat transfer surface to reactor volume will be large, and the reactor will look very much like a heat exchanger as in Fig. 1.5b. If the reaction has to be carried out at a high temperature and is strongly endothermic (for example, the production of ethylene by the thermal cracking of naphtha or ethane—see also Section 1.7.1, Example 1.4), the reactor will be directly fired by the combustion of oil or gas and will look like a pipe furnace (Fig. 1.5c).

Uses Benzene is a clear, colorless, sweet-smelling liquid. Commercial benzene often consists of toluene, xylene, phenol, and traces of carbon disulfide. Benzene in large volumes is produced by fractionation distillation from crude oil, solvent extraction, and as a by-product of coke-oven processing. Benzene is found in coal tar distillates, petroleum naphtha, and gasoline.1... 

Once the synthetic crude oils from coal and oil shale have been upgraded and the heavy ends converted to lighter distillates, further refining by existing processes need not be covered in detail except to note the essential character of the products. The paraffinic syncrude from oil shale yields middle distillates which are excellent jet and diesel fuel stocks. The principal requirements are removal of nitrogen to the extent necessary for good thermal stability of the fuels and adjustment of cut points to meet required pour or freeze points, limited by the presence of waxy straight-chain paraffins. The heavy naphtha from shale oil can be further hydrotreated and catalytically reformed to acceptable octane number, but with considerable loss of volume because of the only moderate content of cyclic hydrocarbons, typically 45-50%. On the other... 

China Taiwan has a nameplate ethylene capacity of 3.6 million tonnes a year of ethylene. This makes Taiwan the fourth largest producer of olefins in the Far East. All of the production is from naphtha so that large volumes of propylene, higher olefins and aromatics are also produced. These feedstocks are used to produce a range of polymers, fibre intermediates and petrochemicals in large integrated complexes. 

Feedstock (after pre-treatment if necessary) is passed along with steam to the pyrolysis furnace. This cracks the compounds in the naphtha, producing a full range of products which are extremely complex. As with gas feedstock, heavier products are produced, but in increased volumes. After quenching a primary fractionator (not present in gas crackers) separates the heavy pyrolysis fuel oil from the cracked gases. 

Space Velocity. Space velocity is defined as volume of naphtha processed per hour per volume of catalyst (or weight of naphtha per hour per weight of catalyst). It determines the limits of product quality (i.e., octane number). The greater the space velocity, the lower the limit, or maximum octane possible. For highly naphthenic feedstocks, high space velocity can be used. For more paraffinic feedstocks, lower space velocity is required to achieve the desired octane number in the product. 

In Figures 5.5 and 5.6, data on the platinum-iridium and platinum-rhenium catalysts are shown for the reforming of a 70-190 C boiling range Persian Gulf naphtha to produce 98 research octane number product at a pressure of 28.2 atm and a temperature of 490 C (33). The naphtha contained (on a liquid volume percentage basis) 69.7% alkanes, 18.5% cycloalkanes, and 11.8% aromatic hydrocarbons. The density of the naphtha was 0.7414 g/cm3. The data in Figure 5.5 show that the platinum-iridium catalyst is almost twice as active as the platinum-rhenium catalyst. 

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