Superheated naphthalene

The unit Kureha operated at Nakoso to process 120,000 metric tons per year of naphtha produces a mix of acetylene and ethylene at a 1 1 ratio. Kureha s development work was directed toward producing ethylene from cmde oil. Their work showed that at extreme operating conditions, 2000°C and short residence time, appreciable acetylene production was possible. In the process, cmde oil or naphtha is sprayed with superheated steam into the specially designed reactor. The steam is superheated to 2000°C in refractory lined, pebble bed regenerative-type heaters. A pair of the heaters are used with countercurrent flows of combustion gas and steam to alternately heat the refractory and produce the superheated steam. In addition to the acetylene and ethylene products, the process produces a variety of by-products including pitch, tars, and oils rich in naphthalene. One of the important attributes of this type of reactor is its abiUty to produce variable quantities of ethylene as a coproduct by dropping the reaction temperature (20—22). 

Naphthalene, xylenes and alkyl benzenes can be purified by sulfonation with concentrated sulfuric acid and crystallisation of the sodium sulfonates. The hydrocarbon is distilled out of the mixture with superheated steam. 

Kinetic analysis with a Langmuir-type rate equation (Equation 13.4) [37] gave us the magnitudes of reaction rate constant (k) and retardation constant due to product naphthalene (K) for the superheated liquid film (0.30 g/1.0 mL) and the suspended states (0.30 g/3.0 mL) with the same Pt/C catalyst as summarized in Table 13.2. It is apparent that excellent performance with carbon-supported platinum nanoparticles in the superheated liquid-film state is realized in dehydrogenation catalysis on the basis of reaction rate and retardation constants. 

Hodoshima, Sv S. Takaiwa, A. Shono, K. Satoh, and Y. Saito, Hydrogen storage by decalin/ naphthalene pair and hydrogen supply to fuel cells by use of superheated liquid-film-type catalysis. Appl. Catal. A, 283(1-2), 235-242 (2005). 

Desulfonation is slower than with naphthalene sulfonic acids.46 It is accomplished by heating the calcium salt with superheated steam in the presence of 85% phosphoric acid,660 or by heating the potassium salt with superheated steam in the presence of sulfuric acid.84... 

Cracking of crude oil in the presence of steam superheated to 2000°C. with the formation, in addition to acetylene and ethylene, of various co-products (fuel gas, propylene, benzene, naphthalene, tars, pitches, etc.). This operation is followed by quenching and primary fractionation. 

Experiments have been carried out on the partitioning of aromatics between gasoline and diesel and superheated water [84]. The increase in the partition coefficient between ambient and 200°C was —10 for benzene, toluene, ethyl benzene and xylenes and -60 for naphthalene, for example. This behavior could be the basis of a process for the removal of benzene from gasoline in particular, and for the removal of aromatics from petroleum products in general. 

The Kureha/ Union Carbide process operates at a higher temperature than the BASF method (Figure 3.46). It uses steam as a heat carrier, at a temperature of 2,000 °C. Preheated crude oil is fed into the superheated steam in an adiabatic reactor, from which 30% ethylene is recovered. Reaction time is only 15 to 20 msec. This process also produces an aromatics-rich oil of relatively high naphthalene content which boils above the pyrolysis gasoline. The aromatic pyrolysis tar concurrently produced can be used to manufacture medium-modulus carbon fibers. 

Divinylbenzene is obtained from diethylbenzene by dehydrogenation, at temperatures in excess of 600 °C with superheated steam (Figure 5.10). o-Diethylben-zene is converted into naphthalene by this process, and this must be separated during subsequent refining of the reaction product, since it contains no polymerizable functional groups and, moreover, it has a certain plasticizing effect. The main application is the manufacture of ion-exchange resins, by co-polymerization with styrene. 

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