Boiling point reactor

Figure 3.33 shows a schematic of the CDTech MTBE/ETBE/TAME process. This is essentially the same as the CDTech MTBE process presented earlier. The process is unique in the sense of using a boiling point reactor and catalytic distillation (CD) [61]. The C4 feed and methanol is fed to the boiling point reactor (1). This is a fixed-bed downflow adiabatic reactor, in which the liquid is heated to its boiling point by the heat of reaction and... 

Figure 3.33 Flowsheet of the CDTech MTBE/ETBE/TAME process. (1) boiling point reactor, (2) CD column, (3) extraction column, (4) methanol recovery column. Source [61].

Another possibility to improve selectivity is to reduce the concentration of monoethanolamine in the reactor by using more than one reactor with intermediate separation of the monoethanolamine. Considering the boiling points of the components given in Table 2.3, then separation by distillation is apparently possible. Unfortunately, repeated distillation operations are likely to be very expensive. Also, there is a market to sell both di- and triethanolamine, even though their value is lower than that of monoethanolamine. Thus, in this case, repeated reaction and separation are probably not justified, and the choice is a single plug-flow reactor. 

The problem with the fiowsheet shown in Fig. 10.5 is that the ferric chloride catalyst is carried from the reactor with the product. This is separated by washing. If a reactor design can be found that prevents the ferric chloride leaving the reactor, the effluent problems created by the washing and neutralization are avoided. Because the ferric chloride is nonvolatile, one way to do this would be to allow the heat of reaction to raise the reaction mixture to the boiling point and remove the product as a vapor, leaving the ferric chloride in the reactor. Unfortunately, if the reaction mixture is allowed to boil, there are two problems ... 

One of the most significant sources of change in isotope ratios is caused by the small mass differences between isotopes and their effects on the physical properties of elements and compounds. For example, ordinary water (mostly Ej O) has a lower density, lower boiling point, and higher vapor pressure than does heavy water (mostly H2 0). Other major changes can occur through exchange processes. Such physical and kinetic differences lead to natural local fractionation of isotopes. Artificial fractionation (enrichment or depletion) of uranium isotopes is the basis for construction of atomic bombs, nuclear power reactors, and depleted uranium weapons. 

High purity acetaldehyde is desirable for oxidation. The aldehyde is diluted with solvent to moderate oxidation and to permit safer operation. In the hquid take-off process, acetaldehyde is maintained at 30—40 wt % and when a vapor product is taken, no more than 6 wt % aldehyde is in the reactor solvent. A considerable recycle stream is returned to the oxidation reactor to increase selectivity. Recycle air, chiefly nitrogen, is added to the air introducted to the reactor at 4000—4500 times the reactor volume per hour. The customary catalyst is a mixture of three parts copper acetate to one part cobalt acetate by weight. Either salt alone is less effective than the mixture. Copper acetate may be as high as 2 wt % in the reaction solvent, but cobalt acetate ought not rise above 0.5 wt %. The reaction is carried out at 45—60°C under 100—300 kPa (15—44 psi). The reaction solvent is far above the boiling point of acetaldehyde, but the reaction is so fast that Httle escapes unoxidized. This temperature helps oxygen absorption, reduces acetaldehyde losses, and inhibits anhydride hydrolysis. 

Alcoholysis (ester interchange) is performed at atmospheric pressure near the boiling point of methanol in carbon steel equipment. Sodium methoxide [124-41 -4] CH ONa, the catalyst, can be prepared in the same reactor by reaction of methanol and metallic sodium, or it can be purchased in methanol solution. Usage is approximately 0.3—1.0 wt % of the triglyceride. 

Removal of maleic and fumaric acids from the cmde malononitrile by fractional distillation is impractical because the boiling points differ only slightly. The impurities are therefore converted into high boiling compounds in a conventional reactor by means of a Diels-Alder reaction with a 1,3-diene. The volatile and nonvolatile by-products are finally removed by two vacuum distillations. The by-products are burned. The yield of malononitrile amounts to 66% based on cyanogen chloride or acetonitrile. 

Manufacture. Phosphoms sulfides are manufactured commercially by direct reaction of the elements. Elemental phosphoms and sulfur are measured into a reaction vessel containing a heel of molten phosphoms sulfide. The reaction can be batch or continuous. The ratio of phosphoms to sulfur in the feed determines which phosphoms sulfur compound (Table 5) is formed. The reaction temperature can be the boiling point or lower. For the boiling reactor (27,28), the phosphoms sulfide product is first purified by distillation and then condensed to a Hquid. Alternatively, the Hquid product can be formed directly in a nondistiUed process (29—31), which may involve a subsequent distillation step (30), and in which the phosphoms is often cleaned up prior to use (30—32). For either process, the Hquid phosphoms sulfide product is soHdified, and usually sized to form a commercial material. 

There are four processes for industrial production of ahyl alcohol. One is alkaline hydrolysis of ahyl chloride (1). In this process, the amount of ahyl chloride, 20 wt % aqueous NaOH solution, water, and steam are controhed as they are added to the reactor and the hydrolysis is carried out at 150 °C, 1.4 MPa (203 psi) and pH 10—12. Under these conditions, conversion of ahyl chloride is 97—98%, and ahyl alcohol is selectively produced in 92—93% yield. The main by-products are diahyl ether and a small amount of high boiling point substance. The alkaU concentration and pH value are important factors. At high alkah concentrations, the amount of by-product, diahyl ether, increases and at low concentrations, conversion of ahyl chloride does not increase. 

Neutralizers can be of three designs, depending on the temperature in the reactor zone. They may operate under, exactly at, or above the atmospheric boiling point of the contained ammonium nitrate solution. 

Sodium is used as a heat-transfer medium in primary and secondary cooling loops of Hquid-metal fast-breeder power reactors (5,155—157). Low neutron cross section, short half-life of the radioisotopes produced, low corrosiveness, low density, low viscosity, low melting point, high boiling point, high thermal conductivity, and low pressure make sodium systems attractive for this appHcation (40). 

The dehydrogenation of the mixture of m- and -ethyltoluenes is similar to that of ethylbenzene, but more dilution steam is required to prevent rapid coking on the catalyst. The recovery and purification of vinyltoluene monomer is considerably more difficult than for styrene owing to the high boiling point and high rate of thermal polymerization of the former and the complexity of the reactor effluent, which contains a large number of by-products. Pressures as low as 2.7 kPa (20 mm Hg) are used to keep distillation temperatures low even in the presence of polymerization inhibitor. The finished vinyltoluene monomer typically has an assay of 99.6%. 

By-products from EDC pyrolysis typically include acetjiene, ethylene, methyl chloride, ethyl chloride, 1,3-butadiene, vinylacetylene, benzene, chloroprene, vinyUdene chloride, 1,1-dichloroethane, chloroform, carbon tetrachloride, 1,1,1-trichloroethane [71-55-6] and other chlorinated hydrocarbons (78). Most of these impurities remain with the unconverted EDC, and are subsequendy removed in EDC purification as light and heavy ends. The lightest compounds, ethylene and acetylene, are taken off with the HCl and end up in the oxychlorination reactor feed. The acetylene can be selectively hydrogenated to ethylene. The compounds that have boiling points near that of vinyl chloride, ie, methyl chloride and 1,3-butadiene, will codistiU with the vinyl chloride product. Chlorine or carbon tetrachloride addition to the pyrolysis reactor feed has been used to suppress methyl chloride formation, whereas 1,3-butadiene, which interferes with PVC polymerization, can be removed by treatment with chlorine or HCl, or by selective hydrogenation. 

If the catalytic HBr oxidation reactor is required to serve as a central facility for recycling a variety of waste HBr streams and conditions that combust all of the organic contaminants cannot be discovered, then further bromine purification operations are probably required. The simplest operation is distillation of the bromine. Due to the high bromine vapor pressure, bromine distillation can be accomplished using relatively small equipment. This is expected to be a highly effective method of purification, particularly where the boiling points of any contaminants are greater than 10°C different from that of bromine. In other applications, absorption or extraction may be needed. 

Since butyraldehyde has a low boiling point (75 °C) separation of catalyst from both reactants and product is straightforward. Most of the rhodium remains in the reactor but prior to recovery of propene and distillation of crude product the gaseous effluents from the reactor are passed through a demister to remove trace amounts of catalyst carried over in the vapour. This ensures virtually complete rhodium recovery. 

To obtain a sample, the reactor was manually pressurized with nitrogen to 10 to 12 psi, and the four-port switching valve was activated to divert the flow of reactor solvent to recycle. The pressure forced about 4 ml of sample through the 5-pl slot of the tantalum valve. The valve was then switched to transfer the sample to the HPLC located about 15 feet away. The solvent for transfer and dynamic dilution was ethoxyethanol, with a boiling point of... 

If the relative boiling points of the components in the reactor product are considered, there is a wide range of volatilities. The sulfur dioxide, butadiene and n-butane are all... 

The use of an unnecessarily high-temperature hot utility or heating medium should be avoided. This may have been a major factor that led to the runaway reaction at Seveso in Italy in 1976, which released toxic material over a wide area. The reactor was liquid-phase and operated in a stirred tank, Figure 27.1. It was left containing an uncompleted batch at around 160°C, well below the temperature at which a runaway reaction could start. The temperature required for a runaway reaction was around 230°C5. The reaction was normally carried out under vacuum at about 160°C in a reactor heated by steam at about 300°C. The temperature of the liquid could not rise above its boiling point of 160°C at the operating pressure. 

R = 8.3145 kJ-K 1-kmol 1 and T is the reactor temperature (K). T is also the supply temperature of A whose yet unknown inventory mA is in the form of a superheated liquid. The total amount of B to be produced is 1000 kmol. T and mA are to be selected with the additional consideration of safety. The normal boiling point of A is 70°C, its latent heat of vaporization is 25,000 kJ-kmol-1, the liquid specific heat capacity is 140 kJ-kmol K 1, and its heat of combustion is 2.5 x 106 k.bkrnol. The residence time of the reactor is 1 min, and the safety is measured in terms of fire and explosion hazards on the basis of the theoretical combustion energy resulting form catastrophic failure of the equipment. 

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