Flow rates membrane reactors

Fig. 6. Allylic alkylation in a continuous flow membrane reactor using dendritic ligand 5c (flow rate 50mLh reactor volume 20 mL, Koch MPF-60 NF membrane, molecular weight cut-off = 400 Da slight increases are due to pump failures) (19b).

Fig. 5. Methane conversion and oxygen flux during partial oxidation of methane in a ceramic membrane reactor. Reaction conditions pressure, 1 atm temperature, 1173 K, feed gas molar ratio, CH Ar = 80/20 feed flow rate, 20 mL min-1 (NTP) catalyst mass, 1.5 g membrane surface area, 8.4 cm2 (57).

C 0.6 g catalyst H20/EtOH = 5-13 Feed Catalysts were prepared by co-precipitation. Reaction was performed in a flow rate 0.05 ml/min membrane reactor. Higher Co loading and lower H20/EtOH ratio increased the... 

A Chromobacterium viscosum lipase is microencapsulated in AOT reversed micelles in isooctane with a Wo=24 and used in the controlled hydrolysis of 50 mM triolein at pH 7.0 and 35°C, in a continous stirred membrane reactor, with a flow rate of 1 l.min 1 Design the reactor in order to achieve 95% of conversion. 

The Pd technology is particularly appropriate for the Livermore site because the water table is fairly far below the surface (20-30 m deep), which makes trenching (e.g. for iron wall barriers) difficult. In addition, the rapid reaction rates and small reactors afforded by Pd catalysis permit the system to be contained within a well bore, which keeps the tritiated water at the site largely below the ground surface. The facility at the Livermore field site consists of two packed bed reactors, place in series in a well-bore. The flow rate is 4 L/min, which yields a residence time of five minutes in the first column and six minutes in the second column. A membrane is used to diffuse hydrogen gas into the influent stream prior to the first reactor. The... 

Figure 13.9 MSR reaction. CH4 equilibrium conversion for both traditional and membrane reactors. I is the ratio ofthe sweep flow rate to the CH4 feed flow rate. H20/CH4 feed molar ratio = 3, permeate pressure = 100 kPa.

Mobile units for photocatalytic treatment have been constructed (126,127). The European Joint Research Center laboratory pilot plant, placed on a truck, includes Ti02 loaded on membranes in UV-irradiated tubular reactors behind microfiltration and ultrafiltration modules. The waste water flow rate for this unit was typically 40 L hr-1, and hydrogen peroxide was added to the photocatalytic process (134). 

The enzymatic reactor consisted of a 500 mL-continuous tank reactor BIOSTAT Q (Braun-Biotech International) coupled to the ultrafiltration membrane. The additional volume of the ultrafiltration unit and piping was around 150 mL. Three solutions were added to the reactor by means of three variable speed peristaltic pumps, containing (a) Orange II, Mn2+ and oxalic acid (b) H2O2 and (c) MnP. Another peristaltic pump was used in order to feed the effluent into the ultrafiltration unit (Fig. 10.3). The recycling feed flow ratio was maintained at 12 1, as this flow rate allowed an adequate homogeneity of the enzymatic mixture but prevented the polarization or fouling of the membrane. 

In the case of dense membranes, where only hydrogen can permeate (permselectivity for H2 is infinite), the permeation rate is generally much lower than the reaction rate (especially when a fixed bed is added to the membrane). Experimental conditions and/or a reactor design which diminishes this gap will have positive effects on the yield. An increase of the sweep gas flow rate (increase of the driving force for H2 permeation) leads to an increase in conversion and, if low reactant flow rates are used (to limit the H2 production), conversions of up to 100% can be predicted [55]. These models of dense membrane reactors explain why large membrane surfaces are needed and why research is directed towards decreasing the thickness of Pd membranes (subsection 9.3.2.2.A.a). 

Fig. 13.8 Change in the percentage of pentachlorophenol (PCP) removal for the electrochemical HDH of saturated aqueous solution using a Nation 117 membrane reactor. Active area 20 cm2. Cathode Pd or Pt/Ti mesh (2 mg Pd or Ptcm-2), Fe or Ni mesh. Anode Pt/Ti mesh (2mgPtcm-2). Anolyte Water. Flow rate 100ml min-1. Applied current density 10mAcm-2. Temperature 17 0.5°C...

Fig. 13.10 Change in space-time yield during the electrochemical HDH of 200 mM DBP in paraffin oil media using a Nation 117 membrane reactor. Ratios of the waste volume (cm3) to the cathode geometric surface area (cm2) are indicated in figure. Cathode Three-layer Ti mesh-supported Pd (25 cm2, 2 mg Pd cm-2). Anode Three-layer Ti mesh-supported Pt (25cm2, 2mgPtcm 2). Controlled current density 10 mAcm-2. Catholyte 200 mM DBP in paraffin oil (50-1,000cm3). Anolyte O.5MH2SO4 aqueous solution (50-1,000cm3). Flow rate 100 ml min-1. Temperature 18.5 0.5°C...

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