Methanol synthesis reactor bubble column

Wu, Y. and Gidaspow, D. (2000), Hydrodynamic simulation of methanol synthesis in gas-liquid slurry bubble column reactors, Chem. Eng. Sci., 55, 573-587. 

Slurry bubble column reactor for methanol and other hydrocarbons productions from synthesis gas is an issue of interest to the energy industries throughout the world. Computational fluid dynamics (CFD) is a recently developed tool which can help in the scale up. We have developed an algorithm for computing the optimum process of fluidized bed reactors. The mathematical technique can be applied to gas solid, liquid-solid, and gas-liquid-solid fluidized bed reactors, as well as the LaPorte slurry bubble column reactor. Our computations for the optimum particle size show that there is a factor of about two differences between 20 and 60 pm size with maximum granular-like temperature (turbulent kinetic energy) near the 60 pm size particles. 

Figure 6.5 Hydrodynamic simulation of methanol synthesis in gas-Uquid slurry bubble column reactors, (a) Reactor operating conditions and simulation grid, (b) Simulated instantaneous distribution of gas and solid holdup, (c) Simulated instantaneous distribution of temperature.

As an alternative to the fixed-bed reactor, the liquid phase methanol (LPMEOH) synthesis was developed (Wender, 1996 Hamelinck and Faaij, 2002). In LPMEOH, syngas dissolves in the liquid phase and diffuses until the reactants reach the catalyst, where they react to produce MeOH. An example of this technology is the slurry bubble column reactor developed by Air Products and Chemicals Inc., which can reach conversions higher than 50% (Air Products, 1998, 2015). 

In the above three processes, the catalysts are all composed of Cu-based methanol synthesis catalyst and methanol dehydration catalyst of AI2O3. The reactors used by JFE and APCI are slurry bubble column, while a circulating slurry bed reactor was used in the pilot plant in Chongqing. It can be foxmd from Table 1 that conversion of CO obtained in the circulating slurry bed reactor developed by Tsinghua University is obvious higher and the operation conditions are milder than the others. 

Gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are widely used in the chemical and petrochemical industries for processes such as methanol synthesis, coal liquefaction, Fischer-Tropsch synthesis and separation methods such as solvent extraction and particle/gas flotation. The hydrodynamic behavior of gas-liquid bubble columns and gas-liquid-solid slurry bubble columns are of great importance for the design and scale-up of reactors. Although the hydrodynamics of the bubble and slurry bubble columns has been a subject of intensive research through experiments and computations, the flow structure quantification of complex multi-phase flows are still not well understood, especially in the three-dimensional region. In bubble and slurry bubble columns, the presence of gas bubbles plays an important role to induce appreciable liquid/solids mixing as well as mass transfer. The flows within these systems are divided into two... 

The oxidation and reduction steps in the RAQ/RAHQ cycle are performed in two separate reactors. A bubble column is applied for the oxidation of the RAHQ, during which HP is produced. For the Pd-catalyzed hydrogenation of the quinones, a slurry, fixed-bed or monolith reactor can be used. After the reactor and L/L settler, a diluted H P-containing water-methanol stream is finally obtained. After the epoxidation step, crude PO is separated and the water-methanol mixture is returned to the HP synthesis process, thus realizing an efficient process integration. 

Table XII. Modelling the Methanol Synthesis in a bubble column slurry reactor (catalyst CuZnAl)...

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