Naphtha grades

To meet the demands of a variety of uses, certain basic naphtha grades are produced, which are identified by boiling range. The complete range of naphtha solvents may be divided, for convenience, into fonr general categories ... 

Although acetic acid and water are not beheved to form an azeotrope, acetic acid is hard to separate from aqueous mixtures. Because a number of common hydrocarbons such as heptane or isooctane form azeotropes with formic acid, one of these hydrocarbons can be added to the reactor oxidate permitting separation of formic acid. Water is decanted in a separator from the condensate. Much greater quantities of formic acid are produced from naphtha than from butane, hence formic acid recovery is more extensive in such plants. Through judicious recycling of the less desirable oxygenates, nearly all major impurities can be oxidized to acetic acid. Final acetic acid purification follows much the same treatments as are used in acetaldehyde oxidation. Acid quahty equivalent to the best analytical grade can be produced in tank car quantities without difficulties. 

Liquid fuels for ground-based gas turbines are best defined today by ASTM Specification D2880. Table 4 Hsts the detailed requirements for five grades which cover the volatility range from naphtha to residual fuel. The grades differ primarily in basic properties related to volatility eg, distillation, flash point, and density of No. 1 GT and No. 2 GT fuels correspond to similar properties of kerosene and diesel fuel respectively. These properties are not limited for No. 0 GT fuel, which allows naphthas and wide-cut distillates. For heavier fuels. No. 3 GT and No. 4 GT, the properties that must be limited are viscosity and trace metals. 

The propylene fractionator operates at a pressure of 1.8 to 2.0 MPa with more than 160 trays required for a high purity propylene product. Often a two-tower design is employed when polymer grade (99.5%+) is required. A pasteurization section may also be used when high purity is required. The bottoms product contains mainly propane that can be recycled to the cracking heaters or used as fuel. Typical tower dimensions and internals for a 450,000 t/yr ethylene plant with naphtha feed are summarized in Table 7. 

Types of fuels ineluded True distillates (naphtha, kerosene, no. 2 diesel, no. 2 fuel oil, JP-4, JP-5) High-quality etudes, slightly eontaminated distillates Navy distillate Residuals and low-grade etude (No. 5 fuel. No. 6 fuel. Bunker C)... 

The majority of today s turbines arc fueled wth natural gas or No. 2 distillate oil. Recently there has been increased interest in the burning of nonstandard liquid fuel oils or applications where fuel treatment is desirable. Gas turbines have been engineered to accommodate a wide spectrum of fuels. Over the years, units have been equipped to burn liquid fuels, including naphtha various grades of distillate, crude oils, and residual oils and blended, coal-derived liquids. Many of these nonstandard fuels require special provisions. For example, light fuels like naphtha require modifications Co the fuel handling system to address high volatility and poor lubricity properties. 

Polyethylene is the most extensively used thermoplastic. The ever-increasing demand for polyethylene is partly due to the availability of the monomer from abundant raw materials (associated gas, LPG, naphtha). Other factors are its relatively low cost, ease of processing the polymer, resistance to chemicals, and its flexibility. World production of all polyethylene grades, approximately 100 billion pounds in 1997, is predicted... 

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. 

C/cIohexane is a colorless, water-insoluble, noncorrosive liquid having a really pungent odor. Its flammable like any naphtha product, and it is shipped in tank cars, tank trucks, barges, and drums. Red DOT shipping labels are required. In commerce, trade is usually done on the basis of Technical Grade (either 95 or 99% purity) or Solvent Grade (85% minimum purity). 

The reasons for the three grades are very practical. For the first two, refinery and chemical, that s the way they re made. Refinery grade propylene streams are generally by-products of a refinery s cat cracker, and the propane/propylene ration is determined by the way the cat cracker is run to make gasoline, not propylene. Chemical grade propylene is usually produced in a naphtha or gas oil cracker. The ratio of propylene and propane is about 92 8 over most of the operating conditions. 

The initial incident involved a pinhole leak on a 6-in. line located 112 feet above grade. The unit might have been shut down at this point, but a decision was made to keep it on line. Efforts to isolate the circuit by closing four block valves failed. The line remained hot and the level in the downstream stripper vessel continued to rise. Several attempts were made to depressure the circuit and free drain all the residual naphtha. At least 15 work orders were issued over a 13-day period and most of these failed to meet the company s own work standards. 

Synonyms Naphtha solvent, high-flash naphtha, refined naphtha, and heavy naphtha describe various fractions and grades. 

Iodine is used in many dyes and as a colorant for foods and cosmetics. Its silver salt is used in photographic negative emulsions. Other industrial applications include dehydrogenation of butane and butylenes to 1,3-butadiene as a catalyst in many organic reactions in treatment of naphtha to yield high octane motor fuel and in preparation of many metals in high purity grade, such as titanium, zirconium and hafnium. 

Jet fuels are typically prepared from either straight-run kerosene or from wide-cut kerosene/naphtha blends off of the atmospheric distillation unit. TABLE 3-10 briefly describes the composition of some typical jet fuel grades. 

In the event of another major war, it is probable that all existing isomerization units would be reactivated and pushed to capacity. Although production of Grade 115/145 aviation fuel required by newer aircraft engines may place somewhat greater emphasis on aromatics, there would still be a demand for maximum alkylate production, and butane isomerization would again play an important role. Expansion of pentane and naphtha isomerization is somewhat less certain and would depend on future developments in aircraft fuels. 

---