Quartz reactor, tubular

Thermolysis of H S was carried out in an open tubular reactor quartz tube with argon/HjS feed over a wide composition spectium (20-100% H S) at four temperatures (1030-1070 K). These experiments show that the reaction is essentially first order in H S partial pressure. Hydrogen yield also increases monotoiucally with feed composition at all temperatures (Adesina et al., 1995). 

The authors measured kinetics using a 0.5 inch quartz tubular reactor. The reference pressures for CO and H20 were 0.026 atm and 0.02 atm, respectively. 

The cracking catalysts were prepared by diluting SAPO-37 samples in a silica matrix. The cracking experiments were carried out in a quartz fixed bed tubular reactor after "in situ" activation. The activation was performed by increasing the temperature up to 823 K at 2K.min ", under N2 flow (240 ml.min"" ). These conditions were maintained for 4 hours, and then N2 was changed to dry air (240 ml.min"" ) for 1 hour. At this point, the temperature was raised (2K.min 1) up to 923 K and maintained overnight. After this treatment all the organic template was removed from SAPO crystals. 

Fast Pyrolysis of Methane in Tubular Reactor. We have conducted a series of experiments on fast pyrolysis of methane using ceramic (alumina) and quartz tubular reactors. 

Methane decomposition experiments were conducted in a 5.0 ml fixed bed quartz microreactor using 0.3 g of catalysts. The catalysts were arranged within the reaction zone in several layers separated with ceramic wool to prevent clogging of the reactor due to produced carbon. The reactor temperature was maintained constant via a type K thermocouple and Love Controls microprocessor. The tubular reactor was made out of alumina and quartz tubings (I.D. 3-6 mm). 

Various laboratory reactors have been described in the literature [3, 11-13]. The most simple one is the packed bed tubular reactor where an amount of catalyst is held between plugs of quartz wool or wire mesh screens which the reactants pass through, preferably in plug flow . For low conversions this reactor is operated in the differential mode, for high conversions over the catalyst bed in the integral mode. By recirculation of the reactor exit flow one can approach a well mixed reactor system, the continuous flow stirred tank reactor (CSTR). This can be done either externally or internally [11, 12]. Without inlet and outlet feed, this reactor becomes a batch reactor, where the composition changes as a function of time (transient operation), in contrast with the steady state operation of the continuous flow reactors. 

Weckhuysen and coworkers (Nijhuis et al., 2003) described equipment suitable for parallel Raman and UV-vis spectroscopic measurements. Openings on the opposite sides of a furnace allowed acquisition of Raman and UV-vis spectra through optical grade windows in a tubular quartz reactor. UV-vis spectra were recorded at 823 K. Gas-phase analysis was achieved with mass spectrometry and gas chromatography. A more advanced version of the design (Nijhuis et al., 2004) accommodates four optical fiber probes, placed at 10-mm vertical spacing along the tubular reactor. The temperature that the fibers can withstand is 973 K the reported spectra characterize samples at 823 K. 

Activity Studies. Propylene conversion over the specified catalysts was performed in a 9 mm o.d. quartz tubular reactor. The amount of catalyst charged into the reactor was 0.1 gram of SAPO-5, while only 0.05 gram of SAPO-11 and SAPO-34 was used to ensure constant contact time. The catalyst powders in the form of fine... 

The synthesis of CNTs was realized in the tubular type quartz reactor [13] on the surface of Si/Si02 substrates at 870°C. Argon flow rate was 100 cmVmin. After 1 min period of the process the reactor was cooled up to room temperature. A series of experiments was carried out with the variation of the ferrocene percentage in the feeding solution (1.0% and 10%) injected into the Ar flow. 

Catalysts were tested in a fixed bed quartz tubular reactor, at atmospheric pressure, in the temperature interval 500-600 C [2]. The catalyst (particle size 0.42-0.59 mm) were mixed with SiC of the same size at a catalyst/SiC volume ratio of 1/4. The feed consisted of a mixture of alkane/oxygen/helium in a molar ratio of 4/8/78 (ethane, propane) and 5/20/75 (n-butane). In order to achieve a similar alkane conversion, samples of 0.7-1.7 g and total flow of 100-200 ml min were used to modify the contact time (W/F). 

Details can be found in Bdlare (ref. 3). The experimental equipment consists of a cumene reservoir, a thermogravimetric analyzer (TGA) and a gas chromatograph (GC). The hdium-cumene mixture enters the TGA, a Cahn System 113DC with a Cahn 2000 Recording Electrobalance, a quartz tubular reactor, and an external split-shell furnace. The catalyst is placed in the sample pan of the microbalance inside the quartz reactor, kept at a controlled temperature in the center of the split-shell furnace. The incremental weight due to coke deposition on the catalyst is monitored by an IBM PC. The reactor exit stream is injected into a Varian 3700 GC using FID. 

The catalytic activity of the nickel molybdates [11] was tested in a 1/4 inch quartz flowthrough tubular reactor operated at atmospheric pressure. The reactor was contained within an electrically heated tube furnace. The temperature of the reactor was controlled according to the temperature of the gases at the base of the catalyst bed. The compiosition and flow rate of the gas feed mixture was measured using MKS mass flow controllers calibrated for each specific gas. Certified gas mixtures with Grade 5 helium (99.999%) as the balance gas were used throughout. 

The catalytic experiments were carried out in a fixed bed quartz tubular reactor at atmospheric pressure in the 500-550 C temperature interval. The catalyst charge was 0.2-1.0 g mixed with 8 g of Norton Silicon Carbide. The feed consisted of propane,... 

It is seen that coke formation on the sample of foil is dependent on the material of the tubular reactor as is the product gas composition. With the steel reactor, preoxidation leads to a substantial increase in the coke formation on the steel foil (Figures 6 and 7). The effect of preoxidation is even more pronounced with Ni as the foil material (Figure 8). On the other hand, preoxidation does not lead to a high rate of coke formation on the steel foil if a quartz liner is used in the tubular reactor (Figure 9). 

Various ways of introducing a sample into a pyrolyser of the tubular reactor (furnace) type have been described. The sample can be introduced into the pyrolysis zone with the aid of a magnet [73], directly by means of a special injector for solid samples [74] and by gravity (free fall) [75]. The latter type of furnace pyrolysers includes a simple vertical device developed by Japanese investigators [75]. It meets the general requirements imposed on pyrolysers of this type, namely (1) it is made of an inert material (quartz) ... 

The gas phase hydrogenation of crotonaldehyde (2-butene-l-al from Aldrich, purity > 99.5%, used without further purification) was carried out in a quartz glass tubular reactor under atmospheric pressure. Typically, 1-10 mg of the chloride precursor were loaded into the reactor. In order to obtain a suitable catalyst bed... 

Reactor The experiments were performed in a continuous flow tubular reactor (Pyrex, 8 mm OD, 5 mm ID). The catalyst sample was held by a plug of quartz wool on top of a thermocouple. All gases and gas mixtures were of high purity grade and not further purified. Calibrated mass flow controllers assured e desired concentrations. 

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