Shell chlorine process

Shell Chlorine Process. The Shell process produces CI2 from the HCl usiag air or O2 ia the preseace of cupric and other chlorides on a siUcate carrier (71). The reaction proceeds at an optimal rate ia the temperature range of 430—475°C at an efficiency of 60—70%. A manufactuting unit was built by Shell ia the Netherlands (41,000 t/yr) and another ia ladia (27,000 t/yr). Both plants have been closed down. 

Van Swaaij, W. P. M., de Vries, R. J., Mantovani, C., and Heijkoop, A., Design Criteria and Performance of the Commercial Reactor for the Shell Chlorine Process, V. Europ. Symp. on Chem. React. Eng., Amsterdam (1972)... 

Van Swaay and Zuiderweg [23] extensively tested the May-van Deemter model as to its ability to scale up the Shell chlorine process (air oxidation of HCl into CI2). To do so they investigated the decomposition of ozone on an FejOs catalyst deposited on sand or silica and carried out gas pulse tracer tests. The bed diameter ranged from 10 to 60 cm, the bed heights from SO to 300 cm. The authors concluded that the van Deemter model adequately describes fluidized bed reactor performance for first-order reactions with a rate coefficient smaller than 2.5 m /kg cat.hr or 1 s" . It follows from their work that with the silica-based catalyst u kj linearly increases from 0.25 m to 0.4 m as u, varies from 6 to 20 cm/s. For fluid beds with a height of up to 1 m, ujkj is proportional to the bed height so that... 

As mentioned in the introduction, the effect of attrition on the particle size distribution is quite often as relevant as the attrition-induced loss is. The reason is quite obvious it is the strong dependence of the process performance on the bed particle size distribution. In the chemical industry, for example, the content of fines, i.e., the mass of particles below 44 microns, has often been observed to have a strong effect on the fluidized bed reactor performance, de Vries et al. (1972) reported an increase in the conversion of gaseous hydrogen chloride in the Shell chlorine process from 91 to 95.7% with an increase of the fines content in the bed material from 7 to 20%. The same effect was observed by Pell and Jordan (1988) with respect to the propylene conversion during the synthesis of acrylonitrile. They reported on an increase of the conversion from 94.6 to 99.2% as the fines content was changed from 23 to 44%. 

De Vries, R.J., W.P.M. Van Swaaij, C. Mantovani and Heijkoop. Design criteria and performance of the commercial reactor for the Shell chlorine process. Ibid. B-9-59... 

The Shell Chlorine Process. The catalyst developed by Shell consists of a mixture of copper(II) chloride and other metallic chlorides on a silicate carrier [202]. The reaction of the stoichiometric mixture of hydrogen chloride and air takes place in a fluidized-bed reactor at ca. 365 °C and 0.1-0.2 MPa. The yield is 75%. The water condenses out from the gas stream, and the hydrogen chloride is removed by washing with dilute hydrochloric acid. After the residual gas has been dried with concentrated sulfuric acid, the chlorine is selectively absorbed, e.g., by disulfur dichloride. After desorption and liquefaction, the chlorine has a purity > 99.95 %. 

A highly economical production of ethyl chloride combines radical ethane chlorination and ethylene hydrochlorination.185 186 Called the Shell integrated process, it uses the hydrogen chloride produced in the first reaction to carry out the second addition step ... 

The process involving ahyl alcohol has not been industrially adopted because of the high production cost of this alcohol. However, if the aUyl alcohol production cost can be markedly reduced, and also if the evaluated cost of hydrogen chloride, which is obtained as a by-product from the substitutive chlorination reaction, is cheap, then this process would have commercial potential. The high temperature propylene—chlorination process was started by Shell Chemical Corporation in 1945 as an industrial process (1). The reaction conditions are a temperature of 500°C, residence timp 2—3 s, pressure 1.5 MPa (218 psi), and an excess of propylene to chlorine. The yield of allyl chloride is 75—80% and the main by-product is dichloropropane, which is obtained as a result of addition of chlorine. Other by-products include monochloropropenes, dichloropropenes, 1,5-hexadiene. At low temperatures, the amount of... 

Chlorination and Chlorination—Dehydrochlorination of Paraffins. Linear internal olefins were produced by Shell at Geismar from 1968 to 1988, using the dehydrochlorination of chlorinated linear paraffins, a process that also yields hydrogen chloride as a by-product. To avoid the production of dichloroparaffins, which are converted to diolefins by dehydrochlorination, chlorination of paraffins is typically limited to 10% conversion. 

Alkyl chlorides. Olefins are chlorinated to alkyl chlorides in a single fluidized bed. HCl reacts with O9 over a copper chloride catalyst to form chlorine. The chlorine reacts with the olefin to form the alkyl chloride. The process developed by the Shell Development Co. uses a recycle of cat yst fines in aqueous HCl to control the temperature [Chem. Proc., 16, 42 (1953)]. 

Most fish is still caught at sea and must be cooled soon after it is taken on board, and kept cold until it can be sold, frozen or otherwise processed [45]. The general practice is to put the fish into refrigerated sea water tanks, kept down to 0°C by direct expansion coils or a remote shell-and-tube evaporator. The sea water must be clean and maybe chlorine dosed. At this condition, fish can be kept for up to four days. 

Apart from the UOP Pacol process, today s only other meaningful economic process is the Shell higher olefin process (SHOP) in which /z-olefins are produced by ethylene oligomerization. Until 1992 Hiils AG used its own technology to produce -60,000 t/year of /z-olefins by the chlorination of /z-paraffins (from Molex plant) and subsequent dehydrochlorination [13]. In the past, the wax cracking process (Shell, Chevron) played a certain role. In the Pacol and Hiils processes, olefins are obtained as diluted solutions in paraffin (Pacol to max. 20%, Hiils about 30%) without further processing these are then used for alkylation. In contrast, the SHOP process produces pure olefins. 

Lidov A process for chlorinating cyclopentadiene to octachloropentadiene, which is then thermally dechlorinated to hexachlorocyclopentadiene (HCCP), used as an intermediate in the manufacture of insecticides and flame retardants. The initial chlorination is catalyzed by phosphoms pentachloride or arsenious oxide. Invented by R. E. Lidov in The Netherlands and commercialized by the Shell Chemical Company. 

Shell Deacon An improved version of the Deacon process for oxidizing hydrogen chloride to chlorine, using a catalyst containing the mixed chlorides of copper, potassium, and rare earths. Formerly operated in The Netherlands and still in operation in India. 

Glycerol. Another synthetic product that is derived from propylene for the production of resins is glycerol. Synthetic production of this material, which started in 1948 at the Houston, Tex., plant of Shell Development Co., culminated a long research program by E. C. Williams and coworkers (45) in which the process was developed through a complex series of reactions starting with the chlorination of propylene (7). The Houston plant has a reported capacity of 36,000,000 pounds per year, which is equivalent to 20% of the prewar production of glycerol (8). 

Next, we investigated the dependence of the chlorine atom concentration in the growing film on the process conditions. To take into account the effect of the local chemical environment of a surface chlorine atom on the probability of its reaction with a water molecule, we used the following dependence of the activation energy of this reaction on the number of the nearest neighboring Zr atoms in the chlorine coordination shell ... 

No doubt the chemical process operators watched in amazement as they started up the filter system with the newly replaced cartridges and they observed rusty colored smoke. Investigators theorized the tin spontaneously caught fire within the hot chlorine atmosphere. Apparently, the cartridges burned with sufficient heat to initiate an iron-in-chlorine fire on the filter body. Operations promptly blocked the upstream chlorine valves and the fire continued to burn until the fire quickly consumed the chlorine gas. The fire destroyed the steel shell of the filter and several inches of downstream piping, but no injuries were reported. 

Alternatives to oxychlorination have also been proposed as part of a balanced VCM plant. In the past, many vinyl chloride manufacturers used a balanced ethylene—acetylene process for a brief period prior to the commercialization of oxychlorination technology. Addition of HC1 to acetylene was used instead of ethylene oxychlorination to consume the HC1 made in EDC pyrolysis. Since the 1950s, the relative costs of ethylene and acetylene have made this route economically unattractive. Another alternative is HC1 oxidation to chlorine, which can subsequendy be used in direct chlorination (131). The Shell-Deacon (132), Kel-Chlor (133), and MT-Chlor (134) processes, as well as a process recendy developed at the University of Southern California (135) are among the available commercial HC1 oxidation technologies. Each has had very limited industrial application, perhaps because the equilibrium reaction is incomplete and the mixture of HC1, CL, CL, and water presents very challenging separation, purification, and handling requirements. HC1 oxidation does not compare favorably with oxychlorination because it also requires twice the direct chlorination capacity for a balanced vinyl chloride plant. Consequendy, it is doubtful that it will ever displace oxychlorination in the production of vinyl chloride by the balanced ethylene process. 

---