Sustainable chemical process technology

Multi-scale modeling for the development of novel types of reactors and processes

The diversification of the natural resources for the production of chemicals, energy and energy carriers is a reality and requires the development of novel types of reactors and processes. Nevertheless, coal, gas oil and natural gas will remain to be important for decades to come. In that context, energy efficiency and CO2 capture for storage or conversion need to be addressed. Novel technologies are developed that allow reducing the cost and energy requirements of important processes for the production of base chemicals. For each process studied, a specific multi-scale modeling approach is taken, requiring a combination of detailed experimental measurements of intrinsic reaction kinetics and transport phenomena and the development of a variety of scale-bridging strategies allowing computationally tractable simulations.

Development of technologies to facilitate CO2 capture and for the production of blue hydrogen

A first step in the conversion of natural gas into chemicals is the production of synthesis gas. Novel technologies allowing to increase the capacity of existing plants and to reduce the cost and energy requirements of new plants are therefore being developed. A major challenge is found in reducing CO2 emissions, requiring the development of technologies that facilitate CO2 capture, i.e. for the production of blue hydrogen. Chemical Looping technologies, such as autothermal Chemical Looping Reforming of natural gas, are studied in this context. The use of electrical or hydrogen-fired furnaces for Steam Methane Reforming is also considered and studied at the reactor and process scale.

Green hydrogen storage and recovery

Hydrogen produced by excess electricity is difficult to store and transport. Conversion to ammonia or to methanol facilitate storage and transport. These chemicals can be used as base chemical or hydrogen can be recovered by cracking. Catalytic cracking of ammonia is studied in this context. The intrinsic reaction kinetics is measured making use of a specially designed micro-reactor set-up. The influence of water on the catalyst activity and the effect of catalyst aging are also studied. For the design of efficient commercial reactors, a multi-scale modeling approach was taken, integrating the catalyst specific kinetic models and accounting for various transport limitations. Integrated heat recovery is considered for improved energy efficiency.

Structured catalysts and bayonet reactors for improving the efficiency of strongly heat transfer limited processes

Process Intensification is a guiding principle in the development of eco-efficient processes and processes for the production of specific high-quality materials. In the context of Steam Methane Reforming (SMR), a strongly heat transfer limited process, structured catalytic reactors are developed that aim at reducing the pressure drop and improving the catalyst efficiency and the heat transfer between the process gas and the tubular wall of the reactor. Heat recovery by means of bayonet reactor designs is considered to optimize the energy efficiency of the process. The intrinsic reaction kinetics, the heat transfer and pressure drop and interfacial transfer are studied individually in specifically designed experimental set-ups. The multi-scale model that is developed integrates the derived kinetic model and mass/heat transfer and pressure drop correlations and allows to optimize existing plants or design new SMR units. The effect of the detailed design of the structure is studied by means of 3D Computational Fluid Dynamics models.
The multi-scale reactor model was validated in a unique SMR pilot plant with a 6-zone electrical furnace. The pilot plant has a single tube of commercial diameter and 1/3 of commercial length, with throughputs 1/3 of commercial, so that space times are comparable to commercial. The pilot plant is designed to operate at pressures up to 30 bara and is equipped with detailed measurement capabilities: gas and tube skin temperature profiles, gas inlet and syngas composition (dry and wet analysis), flow rates and pressure. The SMR pilot plant can operate with classical pellets or with structured catalysts.

High-G fluidized beds and spray dryers making use of vortex chamber technology

A wide variety of fluidized processes, e.g. catalytic cracking of gas oil or biomass drying/torrefaction, can be significantly intensified by fluidizing in a high-G field. High-G fluidization allows intensifying interfacial transfer of species, heat and momentum. The latter allows reducing the formation of bubbles and the fluidization of cohesive particles. Different technologies for high-G fluidization are studied and specific applications developed, e.g. the coating of cohesive powders for food/feed and pharmaceutical applications, the production of powder by means of intensified spray drying etc. By making use of vortex chambers, the geometry is essentially static.
The development of vortex chamber based reactors or drying chambers is both experimentally and numerically studied. Computational Fluid Dynamics studies allow to gain insight in the complex flow pattern and to optimize the reactor design and operating conditions. The experimental studies serve model validation, but were also found to be essential for scaling up the technology. A unique pilot plant Radial Multizone Dryer (RMD) is currently used to study efficient spray drying of various powders for food, feed and energy applications.

CO2 conversion by methanation using green hydrogen – transient process development

A transient process must allow to store CO2 when natural gas needs to be combusted for power generation and then later reconvert the CO2 into methane when excess green energy allows to produce green hydrogen. The transient operation mode requires a combination of efficient adsorption and efficient catalysis of the methanation reaction. As well material, reactor design and process aspects are studied combining experimental measurements and multi-scale modeling and simulation strategies.

 

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Researchers

Senior scientists : Santanu Dey

Projects

• Structured catalytic reactors and application to Steam Methane Reforming
   
• Autothermal Chemical Looping Reforming (a-CLR)
   
• Biomass drying and torrefaction in vortex chambers

 Video A : Formation of a dense and uniform rotating particle bed at high gas-solid slip velocities

Video B : Continuous solids feeding and removal

 

• Wet coating and granulation of cohesive powders in vortex chambers
   
• Application of vortex chambers for the intensification of catalytic fluidized bed processes