Pressure fixed bed

At the end of Wodd War II the butynediol plant and process at Ludwigshafen were studied extensively (67,68). Vadations of the original high pressure, fixed-bed process, which is described below, are stiU in use. However, ak of the recent plants use low pressures and suspended catalysts (69—75). 

Figure 1. Key elements of the TAP reactor (A) and high pressure fixed bed reactor (B) experimental systems. The TAP reactor schematic shows the heated valve manifold and reactor with the elevated pressure attachment located in the main high vacuum chamber. The fixed bed reactor shows the feed system, liquid vaporizer, oxygen disperser, reactor, and waste recovery system.

Figure 4.16 Pressurized fixed-bed reactor synthesis of L-aspartic acid from fumarate applying a plug flow reactor followed by a crystallization step for downstream processing...

Table 78 CO conversion during WGS in an atmospheric pressure fixed bed reactor. The total gas flow was approximately 240 cm3/min, with a composition of 1.6% CO, 52.4% H20,41.9% H2, and 4.1% N2. Note difference in space velocity (factor of 20)431 432...

The Residue Hydroconversion process (Figure 9-27) is a high-pressure fixed-bed trickle-flow hydrocatalytic process. The feedstock can be desalted, atmospheric, or vacuum residue. 

Catalytic tests have been performed in a high pressure fixed bed continuous flow "Catatest unit from VINCI Technologies, France, with the Safanyia atmospheric residue. The experimental conditions employed were a total pressure of 8 MPa, a reaction temperature of 380°C, a liquid hourly space velocity... 

Hydrogenation of CO2 was conducted using a pressurized fixed-bed, flow-type micro-reactor. One gram of pre-reduced catalyst was packed in the reactor tube and was pretreated in-situ at 623 K for 0.5 h in an H2 flow of 200 cm /min. After cooling to room temperature, the gas was switched to H2 - CO2 premixed gas ( H2 / CO2 = 3 ) containing 1% of Ar as an internal standard for GC analysis, and the reaction was carried out under appropriate conditions. The effluent gas was analyzed by on-line gas chromatography with a PEG-1500 column ( 3 m, FID ) and a 2 wt% squalene/active carbon column ( 3 m, TCD ). The tubings from the catalyst bed to the GC were kept hot to avoid condensation of all products. 

The Geminox process oxidizes n-butane in air over a vanadium-phosphorous oxide catalyst in a fluid-bed reactor to maleic anhydride, which is then quenched to maleic acid by absorbing it into water. This highly acidic stream is then pumped to two high-pressure fixed-bed hydrogenation reactors containing carbon-supported catalysts to convert maleic acid to BDO. The major product of reaction, a mixture of 1,4-butanediol, tetrahydrofuran (THF), and y-butyrolactone, is then separated by fractional distillation. The yield of... 

The configuration of the reactor for the supercritical-phase reaction was similar to that of a conventional pressurized fixed-bed flow reactor system. The only difference was that a vaporizer and an ice-cooled high pressure trap were set upstream and downstream of the reactor, respectively, as shown in Figure 4.8-1. To compare characteristic features of the gas-phase, liquid-phase and supercritical-phase reactions, all three kinds of reactions were conducted in the fixed bed reactor. The liquid-phase reaction was operated in a downflow-type trickle bed. The balance materials were nitrogen for the gas-phase reaction, and n-hexadecane and nitrogen for the liquid-phase reaction [15-17]. 

The S-uptake by a non-presulfided M0O3 catalyst was also determined in a pressurized fixed bed flow reactor, by injecting pulses of a lwt% decalin solution of S-labelled dibenzothiophene ( S-DBT), up to the steady state radioactivity of H2 S formed due to HDS of DBT. This took a substantial period of time, as sulfur (SH) formed initially on cat-al3dic sites, or part of it, accommodated on other S-vacancies. The steady state gas phase H2 S radioactivity is reached after the equilibrium between the formation of S-vacancies (due to H2S release), and their occupation (by S-attachment) is approached. The S/Mo ratio from the amount of sulfur. 

Figure 12.3a illustrates an atmospheric pressure fixed-bed reactor used in German FT plants. The catalyst is located between vertical cooling plates, interconnected by horizontal cooling-water pipes. The heat of the reaction is led away from the catalyst by boiling water inside the pipes. The large-scale plants in Germany, France, and Japan were usually operated with these atmospheric pressure reactors. 

The Alkar process using boron trifluoride supported on alumina introduced in 1958 was a high pressure fixed-bed process. The process permitted the utilization of the light olefins (ethylene + propylene) of the refiners gas, which had been burnt as a fuel. The quality of ethylbenzene and isopropyl benzene was excellent. However, commerical experience showed that corrosion problems were still substantial and product pretreatment was necessary to remove boron trifluoride. 

In this work we have evaluated the catalytic properties of the molybdenum-phosphorus catalysts. For this purpose, we have prepared two Ni-Mo-P/AljOj samples following the impregnation sequences (Mo+P->Ni) and (P->Mo->Ni). These samples present the same chemical composition (15 wt% MoOj, 7.5 wtiK PjOj and 5.0 wt% NiO). The catalytic reaction was carried out in a high pressure fixed bed reactor using a vacuum gasoil under typical mild-hydrocracking conditions (T = 653K, P = 5 MPa, LHSV = 0.65 1/h, Hj/Hc = 600). 

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