Tubular reactor, stainless steel

Several types and sizes of VSR s have been installed in the reactors. (See figures 32 and 33). The B, D, F Reactors used tubular boron stainless steel rods approximately 2-1/4 inches in diameter with pinned joints. Later flexible rods with shorter sections and more flexible joints were installed to overcome distortion problems. With flexible rods, cable guides are required to keep the rod straight as it fails into the reactor. 

The hydrocarbon gas feedstock and Hquid sulfur are separately preheated in an externally fired tubular heater. When the gas reaches 480—650°C, it joins the vaporized sulfur. A special venturi nozzle can be used for mixing the two streams (81). The mixed stream flows through a radiantly-heated pipe cod, where some reaction takes place, before entering an adiabatic catalytic reactor. In the adiabatic reactor, the reaction goes to over 90% completion at a temperature of 580—635°C and a pressure of approximately 250—500 kPa (2.5—5.0 atm). Heater tubes are constmcted from high alloy stainless steel and reportedly must be replaced every 2—3 years (79,82—84). Furnaces are generally fired with natural gas or refinery gas, and heat transfer to the tube coil occurs primarily by radiation with no direct contact of the flames on the tubes. Design of the furnace is critical to achieve uniform heat around the tubes to avoid rapid corrosion at "hot spots."... 

Figure 2.2.4 (Berty 1983) shows a tubular reactor that has a thermosiphon temperature control system. The reaction is conducted in the vertical stainless steel tube that can have various diameters, 1/2 in. being the preferred size. If used for fixed bed catalytic studies, it can be charged with a single string of catalytic particles just a bit smaller than the tube, e.g., 5/16 particles in a l/2 O.D. tube. With a smaller catalyst, a tube with an inside diameter of up to three to four particle diameters can be used. With such catalyst charges and a reasonably high Reynolds number— above 500, based on particle diameter—this reactor...

The catalytic reaction was carried out at 270°C and 101.3 kPa in a stainless steel tubular fixed-bed reactor. The premixed reaction solution, with a molar ratio catechol. methanol water of 1 1 6, was fed into the reactor using a micro-feed pump. To change the residence time in the reactor, the catechol molar inlet flow (Fio) and the catalyst mass (met) were varied in the range 10 < Fio <10 mol-h and 2-10 < met < 310 kg. The products were condensed at the reactor outlet and collected for analysis. The products distribution was determined quantitatively by HPLC (column Nucleosil 5Ci8, flow rate, 1 ml-min, operating pressure, 18 MPa, mobile phase, CH3CN H2O =1 9 molar ratio). 

The catalyst testing was carried out in a gas phase downflow stainless steel tubular reactor with on-line gas analysis using a Model 5890 Hewlett-Packard gas chromatograph (GC) equipped with heated in-line automated Valeo sampling valves and a CP-sD 5 or CP-sil 13 capillary WCOT colunm. GC/MS analyses of condensable products, especially with respect to O-isotopic distribution, was also carried out using a CP-sil 13 capillary column. For analysis of chiral compounds, a Chirasil-CD capillary fused silica column was employed. 

For fast reactions (i.e., < 1 min.), open tubular reactors are commonly used. They simply consist of a mixing device and a coiled stainless steel or Teflon capillary tube of narrow bore enclosed in a thermostat. The length of the capillary tube and the flow rate through it control the reaction time. Reagents such as fluorescamine and o-phthalaldehyde are frequently used in this type of system to determine primary amines, amino acids, indoles, hydrazines, etc., in biological and environmental samples. 

The tubular reactor consists of a stainless steel tube (3/8 OD) in which approximately 300 mg of 2% Rh/Al203 is held in place with glass wool and 22 mg of catalyst is loaded in DRIFTS cell. The temperatures are monitored with a K type thermocouple connected to an omega temperature controller. Both pulse and step reaction studies were carried out at 250 °C. 

Fig. 2.4p shows three types of post-column reactor. In the open tubular reactor, after the solutes have been separated on the column, reagent is pumped into the column effluent via a suitable mixing tee. The reactor, which may be a coil of stainless steel or ptfe tube, provides the desired holdup time for the reaction. Finally, the combined streams are passed through the detector. This type of reactor is commonly used in cases where the derivatisation reaction is fairly fast. For slower reactions, segmented stream tubular reactors can be used. With this type, gas bubbles are introduced into the stream at fixed time intervals. The object of this is to reduce axial diffusion of solute zones, and thus to reduce extra-column dispersion. For intermediate reactions, packed bed reactors have been used, in which the reactor may be a column packed with small glass beads. 

Five biomass samples (hazelnut shell, cotton cocoon shell, tea factory waste, olive husk and sprace wood) were pyrolyzed in a laboratory-scale apparatus designed for the purpose of pyrolysis (Demirbas, 2001, 2002a). Figure 6.4 shows the simple experimental setup of pyrolysis. The main element of the experimental device is a vertical cylindrical reactor of stainless steel, 127.0 nun in height, 17.0 nun iimer diameter and 25.0 mm outer diameter inserted vertically into an electrically heated tubular furnace and provided with an electrical heating system power source, with a heating rate of about 5 K/s. The biomass samples ground... 

Temperature-programmed reaction (TPR) studies of partial oxidation of propylene was carried out by flowing CsHe (Praxair), O2 (Praxair), H2 (Praxair) and Ar (Praxair) through DRIFTS and stainless steel tubular reactor (3/8 OD) loaded with catalyst. Feed gas at 40 mFmin and 1 atm consists of C3H6 (10%), O2 (10%), H2 (10%) and Ar (70%) for temperature program reaction studies. Prior to each experiment, the catalyst was pretreated in H2 (10 vol%) and O2 (10 vol%) simultaneously at 250°C. Temperature was monitored with a K type thermocouple connected to an omega temperature controller. 

The catalytic runs were carried out in a stainless steel tubular flow reactor (length = 100 mm, i.d. 4.6 mm) which was connected to a stainless steel air-cooled condenser. Liquid reactants were fed by means of a Waters M-45 high pressure pump. Typically 0.29 g of the catalyst were placed in the reactor between two layers of granular quartz which acts as a preheater. 

A typical UV/H202 plant consists of three major components (1) stainless steel, titanium, or PVDF UV reactor (2) electrical supply and UV lamp controller and (3) dosage equipment to add H202. Usually, the contaminated water is run continuously through a tubular UV reactor that contains a UV... 

After the coal passed through the reactor, the char and any unreacted coal were collected in an air cooled tubular trap containing a stainless steel wool filter attached to the base of the column. The quantity collected is determined by weighing the trap before and after each run. 

Figure 1 shows a schematic view of the tubular reactor. Seamless tubing, of 1/4-inch OD, type 316 stainless steel, was used for the preheater and the reactor. The reactor itself was 187 feet long, wound into a helix of 1 ft. diameter. The reactor and preheater were immersed in separate drums, which were filled with water, and maintained at constant temperature. 

In a microscale tubular reactor, Swern oxidations were performed between —20 and 20 °C. Mixing was performed stagewise with a series of rapid mixing functions (see Figure 5.22) [57,58]. First, dimethyl sulfoxide and trifluoroacetic anhydride were contacted in an interdigital micromixer followed by a stainless steel tube reactor Rl. After addition of the alcohol and reaction in reactor R2, the mixture was then contacted with a triethylamine solution and passed through two more reactors (R3 and R4) to complete the reaction. 

Catalyst evaluations for C02 reforming were performed using a fixed-bed, single-pass quartz tubular flow reactor. The testing unit consisted of a quartz reactor (9 mm x 11 mm x 30") with dimples located at 4" from the bottom, a stainless steel reactor jacket outside the quartz tube, a quartz dead man (3,6 mm x 8 mm x 5"), and a thermowell jacket (2 mm x 3 mm x 27"). It was operated in a downflow mode. 

The catalyst diluted with inert quartz was placed in a tubular stainless steel reactor and the temperature in the bed was measured by a movable thermocouple inserted in a thermowell at the center of the reactor... 

Experimental apparatus used in this study consisted of a 12.5 mm internal diameter stainless steel tubular reactor with a length of 864 mm (34 in). It was originally constructed and used as a trickle bed downflow reactor. With proper modification of the plumbing it was used to regenerate the catalyst in either an upflow or downflow mode. 

Figure 1 shows the equipment used. The tubular reactor was 240 ft (73m) long, 0.5 inch (1.27cm) OD, Type 316 stainless steel. The reactor was placed in an agitated, constant temperature water bath. Two gear pumps were used to give metered flow of the two feed streams-an emulsion of styrene in an equal volume of water, and a solution of potassium persulfate in water. Table 1 shows the recipe used for polymerization. 

The objective was to develop a model for continuous emulsion polymerization of styrene in tubular reactors which predicts the radial and axial profiles of temperature and concentration, and to verify the model using a 240 ft. long, 1/2 in. OD Stainless Steel Tubular reactor. The mathematical model (solved by numerical techniques on a digital computer and based on Smith-Ewart kinetics) accurately predicts the experimental conversion, except at low conversions. Hiqh soap level (1.0%) and low temperature (less than 70°C) permitted the reactor to perform without plugging, giving a uniform latex of 30% solids and up to 90% conversion, with a particle size of about 1000 K and a molecular weight of about 2 X 10 . 

Different types of reactors are utilized for a wide variety of pyrolysis applications, including processing of waste plastics. The worldwide waste plastic pyrolysis systems utilize the fixed-bed designs of vertical shaft reactors and dual fluidized-bed, rotary kiln and multiple hearth reactor systems. The type of reactor used is chiefly based on material to be pyrolyzed and expected products from the pyrolysis. Stainless steel shaking type batch autoclave and stainless steel micro tubular reactors have also been used extensively [14]. Fluidized-bed reactors have been extensively used in producing raw petrochemicals from the pyrolysis of waste plastics [22, 24]. 

Ethane was pyrolyzed in several tubular reactors having internal diameters of about 0.47 cm and a heated length of 107 cm. The reactors used were constructed of Incoloy 800, stainless steel 304 (SS 304), stainless steel 410 (SS 410), Hastelloy X, and Vycor glass. Each reactor was maintained at almost isothermal conditions by suspending it in a fluidized sand bath. More details on the reactors are described by Dunkleman and Albright (12) and Herriott, Eckert, and Albright (13). After suitable pyrolysis, the reactor was cut to expose the coke on the inner surfaces. 

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