260-66?) a 196133 2,831,907 4/1958 Mayfield et a1. Find out about Lean Library here, If you have access to journal via a society or associations, read the instructions below. The exergy method of thermal plant analysis. The dehydrogenation of ethylbenzene to styrene is thus partially eflected in each reaction zone and the effluent from the first reaction zone is thus heated by steam to raise the temperature of the eflluent of the first reaction zone to the desirable level. Type 304 stainless steel is a material of construction with which the art is thoroughly familiar and is the standard designation employed by the American Iron and Steel Institute for stainless steel having the following composition; all percents are by weight: Percent Carbon (maximum) 0.08 Manganese 2.00 Silicon (maximum) 1.00 Chromium 18.00-20.00 Nickel 23.00-12.00 Iron Remainder Type 304 stainless steel (a nickel-containing alloy) is superior to other alloys which do not contain nickel in that the former withstands temperature changes in the interstage heater without undergoing any metallurgical deformation. of hydrocarbons through fired heaters and furnaces. 35. 6. The dehydrogenation of ethylbenzene to styrene is a well known process to which the art has given considerable amount of attention. App Catal A: Gen 2004; 266: 99–108. Second, and more important, is that the injection of steam in this manner limits the quantity of steam which must be mixed with the feed prior to entering the first reaction stage or, if sufficient steam is added to the first reaction stage, limited quantities of steam will be available for interstage heating. The inlet temperature of ethylebenze-steam mixture to the first reaction zone ranges from about 580 C. to about 650 C. and the temperature of the effluent from the first reaction zone ranges from about 580 C. to about 610 C. The entering and exit temperatures of the hydrocarbon-steam mixture in the succeeding reaction zones is about the same as those in the first reaction zone. Unlimited viewing of the article PDF and any associated supplements and figures. According to this invention the dehydrogenation of ethylbenzene to styrene is effected in a plurality of reaction zones with interstage heating. Oxygen atoms, in the form of epoxy or carbonyl groups present at the edges of carbon nanotubes, trigger oxidative dehydrogenation of ethylbenzene to styrene. 2. IN A PROCESS FOR DEHYDROGENATION OF AN ALKYLATED AROMATIC HYDROCARBON IN THE PRESENCE OF STEAM WHICH COMPRISES PASSING A MIXTURE OF SAID HYDROCARBON AND STEAM THROUGH A PLURALITY OF CATALYTIC DEHYDROGENATION REACTION ZONES IN SERIES, WHEREIN THE EFFLUENT FROM ONE REACTION ZONE IS INTRODUCTED INTO THE NEXT REACTION ZONE AND WHEREIN THE TEMPERATURE OF SAID MIXTURE OF HYDROCARBON AND STEAM ENTERING THE FIRST REACTION ZONE RANGES FROM ABOUT 580*C. TO ABUT 650*C., THE IMPROVEMENT WHICH COMPRISES REHEATING THE EFFLUENT FROM EACH REACTION ZONE BY INDIRECT HEAT EXCHANGE WITH STEAM IN A HEAT EXCHANGER CONSTRUCTED OF TYPE 304 STAINLESS STEEL AND USING SAID STEAM FROM SAID HEAT EXCHANGE STEP FOR MIXING WITH SAID HYDROCARBON FEED. and to a lesser extent, benzene. The email address and/or password entered does not match our records, please check and try again. Create a link to share a read only version of this article with your colleagues and friends. 260669 2,851,502 9/1958 Bowman et a1. This example merely serves to illustrate the conditions employed in one illustrative embodiment of this invention. The dehydrogenation of ethylbenzene to styrene over a potassium-promoted iron oxide-based catalyst: a transient kinetic study. The efliuent from reaction zone 11 is introduced via conduit 13 into heat exchanger 3 and leaves said heat exchanger via conduit 15 and enters reaction zone 17. Please check you selected the correct society from the list and entered the user name and password you use to log in to your society website. Recently, the art has restored to the use of multistage reactors with interstage heating in an effort to compensate for the temperature drop resulting from the endothermic nature of the reaction. the site you are agreeing to our use of cookies. Thus, the temperature of the eiiluent from the first reaction zone can be raised to the temperature of the feed to the first reaction zone, or even higher. The non-oxidative dehydrogenation of ethylbenzene to styrene has been studied in membrane reactors consisting of two concentric tubes. When ethylbenzene is passed over CdO in the presence of excess water, what is formed is principally styrene. It has further been discovered that type 304 stainless steel can be employed as a material of construction for the design of the heat exchanger and the interconnecting piping which are employed herein to accomplish the interstage heating. The conventional method has heretofore been to evaporize the ethylbenzene and mix it with steam, in the proper proportion, and then pass the mixture through a catalyst bed disposed in a reactor wherein the dehydrogenation to styrene takes place. It can also be appreciated that this limitation is more pronounced when more than 2 reaction stages are employed. The superior catalytic performance of the present V/Al‐MCM‐41 catalyst can be attributed to the Al‐MCM‐41 support being more favorable for the high dispersion of V species and the stabilization of active V5+ species. to produce vinyl substituted aromatic hydrocarbons. Ethylbenzene dehydrogenation on Fe2O3-Cr2O3-K2CO3 catalysts promoted with transitional metal oxides. Dehydrogenation of Ethylbenzene. The majority of industrial production of styrene follows from the dehydrogenation of ethylbenzene. of steam at an inlet temperature of 681 C. were flowing through the shell side. It has heretofore been believed that type 304 stainless steel is unsuitable as a material of construction when in contact with ethylbenzene at the con ditions which generally prevail in this process, presumably because of its catalyzing effect upon ethylbenzene. No such difficulties are encountered when using type 304 3. stainless steel as the material of construction for the interstage heater. The present invention is more clearly understood with reference to the accompanying drawing which is a schematic flow diagram of one illustrative embodiment of the novel process. 4-. The catalyst which must be employed in the process of this invention is any well-known dehydrogenation catalyst such as ferric oxide-potassium oxide, magnesium oxideferrous oxide-potassium carbonate, aluminasilica-nickel, or any other catalyst which was heretofore used for dehydrogenation of ethylbenzene to styrene. Transactions of the Institute of Measurement and C... Simulation of a reactor used in the catalytic dehydrogenation of ethyl benzene. The inner tube is … The full text of this article hosted at iucr.org is unavailable due to technical difficulties. The efiluent from the first reactor was thus reheated to 604 C. and was introduced into a second reactor containing the same catalyst as the first reactor. The quantity of the steam entering the heat exchanger can be approximately the same as the quantity of the steam injected into the ethylbenzene fed to the first reaction zone. In the dehydrogenation of ethylbenzene to styrene, the quantity of steam .varies from about 12 to about 20 moles of steam per mole of ethylbenzene fed to the first reaction zone, preferably from about 15 to about 18 moles of steam per mole of ethylbenzene. Learn more. Coke Formation and Gasification in the Catalytic Dehydrogenation of Ethylbenzene. 365,350 6 Claims. The conversion to styrene was 50%. The process of claim 1 wherein the dehydrogenation of said alkylated aromatic hydrocarbon is effected in two reaction zones. 260669 DELBERT E. GANTZ, Primary Examiner. If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. The dehydrogenation of ethylbenzene to styrene over a potassium-promoted iron oxide-based catalyst: a transient kinetic study. Kotas, TJ. The process of claim 1 wherein said alkylated aromatic hydrocarbon is ethylbenzene. View or download all content the institution has subscribed to. While the drawing illustrates the use of two reactors to effect the novel process, it is obivous, of course, that a plurality of reaction zones can be employed and provisions made for heating-between stages. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username, orcid.org/https://orcid.org/0000-0003-0011-1627, I have read and accept the Wiley Online Library Terms and Conditions of Use. New login is not successful because the max limit of logins for this user account has been reached. Some of these solutions have been directed to changing the composition of the catalyst in the conventional single-stage reactors. Visitdumrongkul, N, Tippawan, P, Authayanun, S. Zhu XM, Schön M, Bartmann U, et al. Learn about our remote access options, College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024 China. Dulamita N, Maicaneanu, A, Sayle DC, et al. Ye X, Ma N, Hua W, et al. No. The results indicate that the catalytic behavior and the nature of V species depend strongly on the V loading and the support properties. 5. Steam is then added before feeding the … It has also been long recognized that this dehydrogenation reaction is highly endothermic. Bin X, Hengyong X and Wenzhao L. Highly Efficient Nano-sized Fe2O3–K2O Catalyst for Dehydrogenation of Ethylbenzene to Styrene. de Araujo, JCS, Sousa Ch, BA, Oliveira, AC. Babiker K. Abdalla. This heat energy has heretofore been added to the first reactor effluent by either passing said effluent through a furnace or by the injection of steam directly into the efiiuent stream before entering the next reaction stage. Enhanced performance of solid oxide electrolysis cells by integration with a partial oxidation reactor: Energy and exergy analyses, Mg–Fe–Al mixed oxides with mesoporous properties prepared from hydrotalcite as precursors: catalytic behavior in ethylbenzene dehydrogenation, Cu, Fe, or Ni doped molybdenum oxide supported on Al, Entropy production and exergy loss in experimental distillation columns, Exergy analysis of ethylbenzene dehydrogenation to styrene monomer, Modelling the dynamics of regenerative catalytic reactors. 2. In a process for dehydrogenation of an alkylated aromatic hydrocarbon in the presence of steam which comprises passing a mixture of said hydrocarbon and steam through a plurality of catalytic dehydrogenation reaction zones in series, wherein the efiiuent from one reaction zone is introduced into the next reaction zone and wherein the temperature of said mixture of hydrocarbon and steam entering the first reaction zone ranges from about 580 C. to about 650 C., the improvement which comprises reheating the effluent from each reaction zone by indirect heat exchange with steam in a heat exchanger constructed of Type 304 stainless steel and using said steam from said heat exchange step for mixing with said hydrocarbon feed. The mixture of ethylbenzene and steam is then introduced via conduit 9 into catalytic reaction zone 11. Therefore, the reaction is accompanied by a considerable drop in temperature in the reactor, which temperature drop limits the conversion of ethylbenzene to styrene by this process. It is preferable to employ two reactions zones to achieve the desiried degree of conversion of ethylbenzene to styrene by the novel process.