Feedstock saturator

Feedstock Saturator. The feedstock saturator provides over 49% of the process steam (60% with C02 addition). 

Ls = 100 im. Data feedstock saturation temperature = 55 °C (solution concentration = 0.249 kg/kg solution) final batch temperature = 15 °C (solution concentration = 0.113kg/kg solution) crystal density pc = 1750kgm , crystal volume shape factor a = 0.47, solution density pi = llOOkgm". Maximum allowable growth rate G = 5 x 10 m s. ... 

Laboratory trials in a 4L MSMPR cooling crystallizer operated at 15°C with 3Lh of a feedstock saturated at 40 °C (i.e. residence time t = 4/3 = 1.33 h) gave a crystal product with the size analysis plotted in Figure 9.18, the ordinate scale of which corresponds with equation 9.30 describing the CSD in an MSMPR crystallizer. From this linearized plot of the laboratory trial data the dominant size Ld, at M L) = 65%, is found to be 430 pm, and by extrapolation to M L) = 100%, a hypothetical initial crystal size may be estimated as Ln = 40 pm. 

Thermal polymerization is not as effective as catalytic polymerization but has the advantage that it can be used to polymerize saturated materials that caimot be induced to react by catalysts. The process consists of the vapor-phase cracking of, for example, propane and butane, followed by prolonged periods at high temperature (510—595°C) for the reactions to proceed to near completion. Olefins can also be conveniendy polymerized by means of an acid catalyst. Thus, the treated olefin-rich feed stream is contacted with a catalyst, such as sulfuric acid, copper pyrophosphate, or phosphoric acid, at 150—220°C and 1035—8275 kPa (150—1200 psi), depending on feedstock and product requirement. 

Butanol is produced commercially by the indirect hydration of / -butenes. However, current trends are towards the employment of inexpensive Raffinate 11 type feedstocks, ie, C-4 refinery streams containing predominandy / -butenes and saturated C-4s after removal of butadiene and isobutylene. In the traditional indirect hydration process, / -butenes are esterified with Hquid sulfuric acid and the intermediate butyl sulfate esters hydroly2ed. DEA Mineraloel (formerly Deutsche Texaco) currentiy operates a 2-butanol plant employing a direct hydration of / -butenes route (18) with their own proprietary catalyst. 

The other significant industrial route to /-butyl alcohol is the acid cataly2ed hydration of isobutylene (24), a process no longer practiced in the United States. Raffinate 1, C-4 refinery streams containing isobutylene [115-11-7], / -butenes and saturated C-4s or C-4 fluid catalytic cracker (ECC) feedstocks (23)... 

Catalyst choice is strongly influenced by the nature of the feedstock to be hydrotreated. Thus, whereas nickel-promoted and cobalt—nickel-promoted molybdenum catalysts can be used for desulfurization of certain feedstocks and operating conditions, a cobalt-promoted molybdenum catalyst is generally preferred in this appHcation. For denitrogenation and aromatics saturation, nickel-promoted molybdenum catalysts usually are the better choice. When both desulfurization and denitrogenation of a feedstock are required, the choice of catalyst usually is made so that the more difficult operation is achieved satisfactorily. 

Hydrocracking. Hydrogenolysis of a carbon—carbon bond in an organic molecule produces smaller, hydrogen-saturated molecules and is termed hydrocracking when 50% or more of the feedstock is converted into smaller molecules. 

Feeding 1,2-dichloroethane, hydrogen chloride, and oxygen onto a fluidized bed at 400°C produces trichloroethylene and tetrachloroethylene. The catalyst bed consists of cupric chloride and potassium chloride on graphite. A modified oxychlorination technique known as the Transcat process has been developed by the Lummus Co. (32). The feedstock can be a saturated hydrocarbon or chlorohydrocarbon and the process is suited to the production of and chlorohydrocarbons. 

Separation of raw feedstock. The pyrolysis of petroleum feedstream is carried out at 650-900°C at normal pressure in the presence of steam. The so-called steam-cracking process involves carbon-carbon splitting of saturated, unsaturated and aromatic molecules. The following steam-cracker fractions are used as raw materials to produce hydrocarbon resins. 

The first engines invented by Rudolf Diesel ran on groundnut oil, but because of the advent of relatively cheap oil this type of biodiesel never became commercially viable. Since about 1930 the diesel engine has been refined and fine tuned to run on the diesel fraction of crude oil, which consists mainly of saturated hydrocarbons. For this reason the modem diesel engine cannot run satisfactorily on a pure vegetable oil feedstock because of problems of high viscosity, deposit formation in the injection system and poor cold-start properties. Today, however, environmental... 

Saturated hydrocarbons are the main constituents of petroleum and natural gas. Mainly used as fuels for energy production they also provide a favorable, inexpensive feedstock for chemical industry [74]. Unfortunately, the inertness of alkanes renders their chemical conversion challenging with respect to selectivity. Clearly, the development of new and improved methods for the selective transformation of alkanes belongs to the central goals of catalysis. Iron-catalyzed processes might be a smart tool for such transformations (for reviews see [75-77]). 

Table 41.3 shows a performance comparison of Pt/Pd TUD-1 with a commercial Pt/Pd catalyst (26). The feedstock is a typical straight run gasoil ( SRGO ), a distillate precursor to diesel fuel. Under identical test conditions, the TUD-1 catalyst achieved 75% aromatics saturation versus 50% for the same volume of commercial catalyst. This superior result is particularly interesting because the TUD-1 catalyst had a much lower density than the commercial material, so that less catalyst by weight was required in the reactor. 

The kinetics of hydrocracking reactions has been studied with real feedstocks and apparent kinetic equations have been proposed. First-order kinetics with activation energy close to 50 kcal/gmol was derived for VGO. The reactions declines as metal removal > olefin saturation > sulfur removal > nitrogen removal > saturation of rings > cracking of naphthenes > cracking of paraffins [102],... 

Hexachloroethane is not currently produced for commercial distribution in the United States. It is a by-product in the industrial chlorination of saturated and unsaturated C2 hydrocarbons by several U.S. companies, including Dow Chemical, PPG Industries, and Occidental Petroleum Corporation. The product may be used captively in-house or recycled in feedstock to produce tetrachloroethylene or carbon tetrachloride. Estimates of current production volumes were not located (Gordon et al. 1991 Santodonato et al. 1985 TRI93 1995). 

The measurement of the width of the metastable zone is discussed in Section 15.2.4, and typical data are shown in Table 15.2. Provided the actual solution concentration and the corresponding equilibrium saturation concentration at a given temperature are known, the supersaturation may be calculated from equations 15.1-15.3. Data on the solubility for two- and three-component systems have been presented by Seidell and Linkiv22 , Stephen et alS23, > and Broul et a/. 24. Supersaturation concentrations may be determined by measuring a concentration-dependent property of the system such as density or refractive index, preferably in situ on the plant. On industrial plant, both temperature and feedstock concentration can fluctuate, making the assessment of supersaturation difficult. Under these conditions, the use of a mass balance based on feedstock and exit-liquor concentrations and crystal production rates, averaged over a period of time, is usually an adequate approach. 

A vacuum crystalliser operates on a slightly different principle from the reduced-pressure unit since supersaturation is achieved by simultaneous evaporation and adiabatic cooling of the feedstock. A hot, saturated solution is fed into an insulated vessel maintained under reduced pressure. If the feed liquor temperature is higher than the boiling point of the solution under the low pressure existing in the vessel, the liquor cools adiabatically to this temperature and the sensible heat and any heat of crystallisation liberated by the solution evaporate solvent and concentrate the solution. 

Figures 13 and 14 also show that hydrotreating the catalytic cracker feedstock increases the zeolite cracking. C3, and C5+ compounds are possible products of primary zeolite cracking. These figures show that hydrotreating of the feedstock results in larger yields of these primary cracking products and hence more valuable products. This improvement is most likely due to the heteroatom removal and the saturation of aromatic compounds during hydrotreating which tend to block active sites and reduce the activity of the catalyst.

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