Mach number methanol

When ethanoi is present, the risk of separation is much less than with methanol. Nevertheless, the ethanol should be relatively anhydrous (less than 3000 ppm water) moreover, if a fuel containing ethanol comes in contact with a water layer, a migration of ethanol toward the water is observed creating a fuel quality problem manifested by lower octane number and an environmental quality problem in that the water will need to be treated. Distribution of ethanol-based fuels requires extra precaution to ensure dryness in distribution systems.  [c.244]

Tertiary-Amyl Methyl Ether. Like MTBE, TAME is produced by the simple reaction of methanol and isoamylenes (2-methyl-l-butene and 2-methyl-2-butene). It is used for gasoline blending, and also as a feedstock to make high purity isoamylene. Its use in gasoline octane blending has not grown nearly as fast as MTBE because of less favorable economics (TAME s lower octane number). However, with the future need for gasolines that have lower vapor pressure and contain oxygen, TAME capacity is expected to grow using isoamylene produced by refinery catalytic crackers (24).  [c.429]

From the equation it is obvious that a large contraction of volume takes place. For every mole of methanol made, two mole volumes disappear. The volumetric flow and superficial linear velocity will change substantially, with some physical properties changing too. Only the mass velocity will remain constant, and the Reynolds number will change little with the changing viscosities. All this will influence pressure drop, and must be taken into account. The heat transfer coefficient will change very little and can be neglected. A diagram for model development appears in Figure 8.1.2.  [c.166]

Molecular sieves will adsorb water molecules and other contaminants from liquids and gases down to very low levels - often just 1 part per million. Examples of the applications of the differing molecular sieve grades are Grade 3 A - Dries unsaturated gases and organic liquids (e.g., methanol). Used to remove water from cleaning fluids in ultrasonic baths. Grade 4A-lsz general dryer of liquids, natural gases. Also an excellent adsorber of carbon dioxide. Grade 10 A/13X - Is used in air prepurification (due to its high water and carbon dioxide adsorption eapacity) and also adsorbs sulphur compounds ( sweetens ). It will remove decomposition products following the quenching of arcing in electrical products. Molecular sieves properties as desiccants differ from silica gel in a number of ways (1) They adsorb water vapor more rapidly than silica gel (2) They will reduce water vapor to much  [c.153]

Due to the high reactivity of methanol, many chemicals could be derived from it. For example, it could be oxidized to formaldehyde, an important chemical building block, carbonylated to acetic acid, and dehydrated and polymerized to hydrocarbons in the gasoline range (MTG process). Methanol reacts almost quantitatively with isobutene and isoamylenes, producing methyl t-butylether (MTBE) and tertiary amyl methyl ether (TAME), respectively. Both are important gasoline additives for raising the octane number and reducing carbon monoxide and hydrocarbon exhaust emissions. Additionally, much of the current work is centered on the use of shape-selective catalysts to convert methanol to light olefins as a possible future source of ethylene and propylene. The subject has been reviewed by Chang.  [c.149]

There has been much interest in the mobility of species adsorbed on or in layer and cage minerals such as clays and zeolites (see Fig. XVII-26 for an illustrative structure of the latter). As one example, in the case of benzene adsorbed on a zeolite, C NMR showed a line broadening (and hence correlation time) which increased with , the number of molecules per cage, up to n = 4. Beyond this point there was a rapid line narrowing, indicating that a new, highly mobile phase was present [99]. In a study of chemisorbed methanol on MgO, C NMR indicated molecules to be rigidly bound below a half monolayer coverage but that higher coverages produced isotropically rotating molecules [100]. As another illustration, zeolite rho is a relatively flexible zeolite with useful catalytic properties. Xenon-129 NMR spectroscopy indicates this flexibility and also that there can be rapid exchange between two kinds of adsorption sites [101-103]. Finally, it has been possible to determine the long-range diffusion coefficient of N2 in commercial zeolite crystals, using pulsed field gradient NMR. Values of ranging from 10 to 10 cm /sec were found [103a].  [c.588]

In many applications in mass spectrometry (MS), the sample to be analyzed is present as a solution in a solvent, such as methanol or acetonitrile, or an aqueous one, as with body fluids. The solution may be an effluent from a liquid chromatography (LC) column. In any case, a solution flows into the front end of a mass spectrometer, but before it can provide a mass spectrum, the bulk of the solvent must be removed without losing the sample (solute). If the solvent is not removed, then its vaporization as it enters the ion source would produce a large increase in pressure and stop the spectrometer from working. At the same time that the solvent is removed, the dissolved sample must be retained so that its mass spectrum can be measured. There are several means of effecting this differentiation between carrier solvent and the solute of interest, and thermospray is just one of them. Plasmaspray is a variant of thermospray in which the basic method of solvent removal is the same, but the number of ions obtained is enhanced (see below).  [c.71]

Stannic Chloride. Stannic chloride is available commercially as anhydrous stannic chloride, SnCl (tin(IV) chloride) stannic chloride pentahydrate, SnCl 5H20 and in proprietary solutions for special appHcations. Anhydrous stannic chloride, a colorless Aiming Hquid, fumes only in moist air, with the subsequent hydrolysis producing finely divided hydrated tin oxide or basic chloride. It is soluble in water, carbon tetrachloride, benzene, toluene, kerosene, gasoline, methanol, and many other organic solvents. With water, it forms a number of hydrates, of which the most important is the pentahydrate. Although stannic chloride is an almost perfect electrical insulator, traces of water make it a weak conductor.  [c.65]

Manufacture. MTBE is easily made by the selective reaction of isobutylene and methanol over an acidic ion-exchange resin catalyst, in the Hquid phase and at temperatures below 100°C. To be economically competitive, MTBE s use as an octane enhancer in gasoline has been dependent on low cost isobutylene. There are a number of possible isobutylene sources for making MTBE (see Butylenes). During the 1980s, much of the MTBE was made with isobutylene contained in mixed butanes /butylenes process streams that was produced from petrochemical olefin plants or refinery fluid catalytic crackers. MTBE plant sizes from these feedstock sources are limited by the amount of by-product isobutylene produced in these operations, and are usually in the range of one to six thousand barrels per day (40 to 250 t/yr). Larger amounts of isobutylene for MTBE can be made from butanes by first isomerizing the normal butanes to isobutane, and then dehydrogenating to isobutylene. This is a much more capital intensive process, and therefore the plant sizes in the United States are usually at least 500,000 t/yr to be economically competitive. Even at this size, it is stiU a relatively higher cost source of MTBE than that made from by-product isobutylene in ethylene plants or refineries. However, because of the growing need to meet the gasoline oxygen requirements for the U.S. Clean Air Act, many of these world-scale MTBE plants will need to be built (24).  [c.428]

Nowhere is this conflict more evident than in organic chemistry. To take one example, organic chemists describe the oxygen-hydrogen (OH) bond as a polar covalent bond. This description is valid for virtually every OH - containing molecule in existence, and it turns out that many OH molecules share common characteristics that can be attributed to this peculiar bond. The generalities tend to fall apart, though, when applied to specific molecules. Methanol, CH -OH, and octanol, CH3CH2CH2CH2CH2CH2CH2CH2-OH, both contain a polar covalent OH bond, but while this bond can make any number of methanol molecules dissolve in water, octanol is insoluble.  [c.1]

See pages that mention the term Mach number methanol : [c.202]    [c.1144]    [c.420]   
Pressure safety design practices for refinery and chemical operations (1998) -- [ c.233 ]