Synthesis of methanol in microchnnel

Systematic experimental data have been obtained on the results of catalytic chemical reactions in a microchannel reactor for the synthesis of methanol from synthesis gas. Synthesis gas contains hydrogen, carbon monoxide and dioxide, as well as nitrogen in the ratio 58/29/5/8. The experiments were carried out at different flow rates in the temperature range 190-260C. Experiments were also carried out for methanol synthesis in fixed bed reactor at different synthesis pressures.

High-quality mesoporous SiO2 nanospheres via a confined jet impingement continuous microchannel reactor

High surface area mesoporous silica (SiO2) nanospheres has been considered an ideal material for the catalytic, adsorption and drug delivery. However, synthesis of ultra-high specific surface area mesoporous silica nanoparticles with well-defined sphere structure and small particle size (< 200 nm) is still challenging. Here, a two-stream confined jet impingement continuous microchannel reactor is proposed to produce novel mesoporous silica nanospheres (MSNs) with ultra-high specific surface area (SSA) and abundant worm-like meso-porosity. The as-obtained MSNs with worm-like mesoporous structure were produced with average particle diameter of 142 ~ 207 nm, high SSA of 1347 ~ 1854 m2/g, total pore volume of 0.86 ~ 1.23 cm3/g and pore diameter of 2.6 ~ 3.3nm. Moreover, the shear force field in the microchannel reactor on the mesoscopic structure of MSNs was simulated by mesoscopic kinetics. Additionally, MSNs was used as the silicon source to synthesize lithium silicate (Li4SiO4), which enhanced carbon dioxide (CO2) adsorption of 27.18 wt% at 650 ℃.

Towards a High-Pressure Microchannel Reactor for Fuel Characterization

Within the area of combustion, externally heated microtubes have been introduced to study the combustion characteristics of fuels and fuel blends. Microreactors have advantages over other conventional fuel testing methods because of their potential to test small volumes (&lt; 20 μl) at high throughput. In this work, a high-pressure microreactor is designed and implemented to test fuels up to a pressure of 20 bar where automated testing reduces test time substantially. The novelty of this device is its capability to operate at pressure exceeding the current state of the art of 12 bar. The combustion behavior of fuels is tested in an externally heated quartz tube, with a diameter less than the conventional quenching diameter of the fuel. The ultimate objective of the experiment is to investigate the impact of fuel on flame characteristics. The ability to reach engine relevant pressure conditions and its inherent small volume requirements make this device a potential candidate for measurements of laboratory transportation fuels and fuel blends. For initial validation, tests from an earlier intermediate pressure experiment with ethane/air and nitrogen mixtures are repeated. Chemiluminescence images are taken to evaluate the combustion characteristics in terms of the three classical flame regimes: weak flames, Flames with Repetitive Extinction, and Ignition (FREI) and normal flames. Previous results at intermediate pressure showed that as the pressure increases, the weak flame and FREI regimes shift towards lower velocities. Also, as dilution level increase (i.e. reducing oxygen concentration), the transition from the weak flame to FREI becomes less abrupt and is completely lost for marginal oxygen concentration. The objective of this study is to document flame dynamics at higher pressures.

Optimal control of the Sabatier process in microchannel reactors

We consider the optimization of a chemical microchannel reactor by means of PDE-constrained optimization techniques, using the example of the Sabatier reaction. To model the chemically reacting flow in the microchannels, we introduce a three- and a one-dimensional model. As these are given by strongly coupled and highly nonlinear systems of partial differential equations (PDEs), we present our software package cashocs which implements the adjoint approach and facilitates the numerical solution of the subsequent optimization problems. We solve a parameter identification problem numerically to determine necessary kinetic parameters for the models from experimental data given in the literature. The obtained results show excellent agreement to the measurements. Finally, we present two optimization problems for optimizing the reactor’s product yield. First, we use a tracking-type cost functional to maximize the reactant conversion, keep the flow rate of the reactor fixed, and use its wall temperature as optimization variable. Second, we consider the wall temperature and the inlet gas velocity as optimization variables, use an objective functional for maximizing the flow rate in the reactor, and ensure the quality of the product by means of a state constraint. The results obtained from solving these problems numerically show great potential for improving the design of the microreactor.