Sustainable flux operations

Sustainable Flux Operation Balances the capital cost of lowering flux with the benefits of less fouling and cleaning. 

Sustainable Flux Operation Typical fluxes are chosen in the modest range of 10-30 L/m h to avoid cake formation of biomass. 

The multitubular PBR configuration is preferred when convection is not sufficient for defivering the necessary heat flux to sustain the operation. However, in most of the exothermic and endothermic reactions, the temperature of the catalyst bed can be regulated by convective external heat transfer. In... 

The characteristic TMP history for a submerged membrane with cross flow (bubbling) is depicted in Figure 10.2a. Due to deposition TMP rises slowly, and the rate of rise is less with more imposed shear or lower solids. In an idealized situation TMP would remain unchanged at subcritical flux conditions. However, for various reasons (see Section 10.5.1) some degree of TMP rise tends to occur at aU fluxes so the interest is in the acceptable rate of rise and the sustainable flux. Figure 10.2a also includes the potential for a sudden TMP jump that can be observed in prolonged operation at constant flux (discussed further in Section 10.5.1). 

Values of SAD range from 1.0 down to about 0.2 Nm/h, and data are plotted in Figure 10.13 versus membrane permeability (L/m h bar). SAD ranges from about 60 down to as low as 10, with typical values from 20 to 15. The permeabilities in Figure 10.13 are based on long-term operation and can be considered as sustainable flux... 

It is generally accepted that cyanobacterial TCA cycle is not very active under phototrophic conditions. A recent study further proved that it operates in a bifurcated way [112]. However, the bifurcated pattern switches to a dominantly cyclic pattern by introducing an ethylene-forming enzyme from Pseudomonas. Ethylene can be sustainably and efficiently produced from 2-oxoglutarate while also activating the TCA cycle metabolism. The enhanced flux via the remodeled TCA is 37% of the total fixed carbon which is higher than the 13% found in wild type. This result indicates that the metabolic malleability of the cyanobacterial TCA cycle depends on what it produces. 

Membrane Distillation (MD) is a hybrid thermal-membrane process that could be applied in produced water volume reduction applications while simultaneously augmenting sustainable water production in Qatar. A consortium of ConocoPhillips - Global Water Sustainability Center (GWSC), Qatar University (QU) and Qatar Electricity Water Company (QEWC), was formed to assess the suitability of MD to treat high salinity brines from thermal desalination plants similar salinity levels could be found in produced water. The pilot scale results showed that MD could operate at 50% recovery and achieve a stable flux of 5 L/(m. h) at when treating thermal brine at 70,000 mg/L TDS. The effluent produced contained < 10 mg/L TDS. 

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