Gas-liquid hydrogenation

Compared with hydrogen as a gas, liquid hydrogen has a much higher volume-related energy density and is, therefore, principally better suited for storage, for example, on-board vehicles and for transport applications (see also Chapter ll).4 However, hydrogen liquefaction is an energy-intensive process. 

Four different methods to store hydrogen are currently available compressed gas, liquid hydrogen, metal hydrides and sorption on different porous materials (carbon materials, zeolites, metal organic frameworks, etc).2-4... 

Industrial gas-liquid hydrogenation reactions are carried out in slurry and trickle-bed reactors (Ref. 3). Modeling of the latter has been advanced significantly in the last two decades (Refs. 4-6). Predictions of trickle-bed reactors performance were in good agreement with experimental data (Ref.7). 

Gas-liquid- Hydrogenations (olefins, edible oils, several chloro and nitro aromatics), solid Oxidations (p-xylene). Fermentations (alcohol, single cell proteins,... 

A comparison of the volumetric energy densities of compressed hydrogen gas, liquid hydrogen and other fuels is presented in Figure 1.11 methane represents natural gas and octane represents petrol. The data show that highly compressed methane and liquid fuels are much superior to hydrogen. 

Table 4.3 lists some typical gas-liquid hydrogenation reactions investigated in order to explore the features of three-phase catalytic membrane reactors. An example of the application of three-phase catalytic membrane reactors to the hydrogenation of sunflower seed oil can be found in Veldsmk (2001), where it was shown that for this hydrogenation running under kinet-ically controlled conditions the interfacial transport resistances and intraparticle diffusion limitations did not have any effect. Unfortunately the catalyst underwent a serious deactivation process. 

Table 4.3 Examples of gas-liquid hydrogenation carried out with catalytic membrane reactors... 

FIGURE 8.3 Cold Gas Liquid Hydrogen Bubbie Point as a Function of the Liquid Screen Side Temperature. 

FIGURE 8.4 Heated Pressurant Gas Liquid Hydrogen Bubble Point Pressure as a Function of the Temperature Difference between Pressurant Gas and Liquid. 

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