Stainless steel micro-reactor

Comparing the performance of the micro structured reactor with a ceramic monolith at 230 °C reaction temperature and a GHSV of 300 000 h 1, the conversion in the micro reactor was 94%, whereas 86% was found for the monolith, which was attributed to the improved heat and mass transfer in the metallic micro-structures (see Figure 2.89). The GHSV value of 500 000 h 1 corresponds to a dry gas flow rate of440 Ndm3 h 1. However, the stability of the catalyst coated on the monolith was superior to that of the catalyst coated on the micro structured stainless-steel plates. 

The whole process consists of a sequence of consecutive steps which allows separation into production modules. Some of them already exist and will just need slight modifications. Others have to be developed. At the very beginning, one makes use of the newly developed reel-to-reel etching technology for micro structured stainless-steel foils similar to the process described in [166], The structured foils are then coated with catalyst, structured again with a laser tool and finally folded by sheet metal forming to a reactor monolith. The readily mass-produced reactors will be sealed by laser welding. 

Actually, various efforts have been made to develop the compact and efficient microchannel PrOx reactor for portable PEMFC applications. Goerke et al. [2] reported micro PrOx reactor employing stainless steel microchannel foil and Cu/Ce02 catalyst. They showed more than 99% CO conversion at less than 150 C and residence time of 14ms while CO selectivity was about 20%. Chen et al. [3] also developed microchannel reactor made of... 

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 reactor can be obtained in many materials such as aluminum alloys, copper, silver, titanium and stainless steel. The number of stacked platelets, the dimensions of the micro channels on the platelets and the fluidic connectors were also varied. Pressure tightness up to 25 bar and He tightness were demonstrated, although this is certainly not the upper limit. 

A test reactor was made of stainless steel which contains a so-called micro-strip electrode array [75]. This array is composed of thin strips surrounded by larger objects. The anodes are thin gold strips evaporated on glass bulk. The cathodes have a more complex bulky pattern similar to an oval. 

Reactor type Slit-type interdigial micro mixer-tube Mixer material Stainless steel, nickel... 

Reactor material Stainless steel Surface-to-volume ratio of reaction micro channels lOOOOm m- ... 

OS 13] [R 17] [no protocol] Using a micro mixer/commercial tube reactor, the synthesis of a thiourea from phenyl isothiocyanate and cyclohexylamine at 0 °C was carried out [85] (see a more detailed description in [42]). A single mixing device connected to a stainless-steel tube of about 10 m length and 0.25 mm diameter was used. The feasibility of performing a nearly spontaneous reaction could be shown. 

Reactor type Dual-channel micro reactor Base plate material of interfacing chip housing Silicon stainless steel... 

The micro reactor consisted of a pair of iron plates coated with Pd catalyst placed on disk-type polypropylene holders [20]. This micro channel device was encased in a stainless-steel housing. The thickness of the catalyst layer was approximately 5.0 pm 10 mg catalyst was deposited per plate, so giving 20 mg in total. The specific surface area of the catalyst was 3.6 0.4 m g ... 

GL 19] [R 9] [P 20] The temperature range of a micro-reactor test imit is similar to that of a mini batch reactor, whereas the range for pressure operation is different (temperature micro reactor, 20-80 °C mini batch, 20-100 °C pressure micro reactor, 1-11 bar mini batch, 1-100 bar) [70], This is caused by the choice of glass as tube material for the micro reactor and may be overcome in the future by choosing stainless steel. 

Toluene disproportionation was carried out in a high-pressure continuous flow micro reactor. Granular catalyst (32-64 mesh, 2.5 cm ) was loaded into a stainless steel tube reactor. Toluene was fed at a rate of 10 cm h (liquid) in the flow of H2S(0.2vol.%)/H2 mixture gas (200 cm min b at 623K and 6MPa. The effluent was analyzed by gas chromatography (Shimadzu, GC-9A) by a flame ionization detector (FID). 

All reactions were carried out at standard conditions using 0.5 g catalyst in a stainless steel micro-reactor (Autoclave Engineers) with a H2 flow of 7 [imol s 1 at 623 K and atmospheric pressure. The catalysts were activated by reduction in dry hydrogen at 773 K for 16 h. The hydrogen gas was ultra... 

A stack-like reactor was applied for catalyst testing for the reaction by Chen et al. [38], Four micro structured foils made of stainless steel formed the stack, which were 340 pm thick, carrying 48 channels 170 pm deep and 500 pm wide (see Figure 2.14). 

Chen et al. [36] performed a comparison of micro structured steel and aluminum plates with a conventional monolith by varying the GHSV. Full conversion could be maintained for autothermal methanol reforming in the micro structures up to a GHSV of 40 000h 1, whereas conversion dropped to 80% at 20 000h 1 at the monolith. Even at 186 000 h, still 95% conversion could be achieved in the stainless-steel micro reactor. No significant performance differences were observed between the steel and aluminum plates. 

The dimensions of the stainless-steel micro structured reformer are 75 mm x 45 mm x 110 mm. It consists of a stack of micro structured steel foils coated with catalyst and tempered by heating cartridges in the reactor housing. Laser-cut graphite foils were used to seal the reformer under operating conditions up to 200 °C at a flow rate up to 900 ml min-1 and a residence time of 0.07 s. 

For periodic reuse of the enzymes a new project was developed including a microreactor incorporated into the FIA system. The micro-reactor shown in Fig. 2, made of acrylic acid and with a 0.91-mL void volume, and length-to-diameter ratio of 3 1, was packed with AOD immobilized on glass beads. The beads were retained in the microreactor with a 110-mesh nylon screen and two rubber O-rings with an 11.4-mm external diameter. The lids were attached to the microreactor with four stainless steel screws. 

The stainless steel micro reactor (figure 2) is constructed for catalyst pellet sizes of 0.175 to 0.20 mm. The reactor exit is connected via 0.9 m stainless steel capillary (i.d. 0.2 mm) to the analysing unit. The reactor and part of the capillary is mounted in an electric oven. A continuous stream of carrier gas passes the four way valve, then the catalyst bed, and flows via a stainless steel capillary into the detector. The carrier gas can be switched to pulse gas with the four way valve. The pressure in the reactor is determined by the resistance of flow in the capillary. The pressure difference between the carrier gas and the pulse gas is measured with a differential pressure detector. During the experiment the gas velocities of the carrier and the pulse gas are equal. The gasses are regulated by mass flow controllers. The gases used in the experiments were of a high purity. 

Figure 2. A representation of the stainless steel micro reactor used.

Methods. Reactions were run in stainless steel micro-autoclaves of 30 mL. capacity. Reactors were charged with 20 g. tetralin plus the appropriate additive, flushed with... 

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