Conceptual design of an integrated thermally self-sustained methanol steam reformer

We have investigated the concept of an integrated system for small, manportable power units. The focus of this study is the direct thermal coupling of a methanol steam reformer (MSR) and a high-temperature proton exchange membrane fuel cell (HT PEMFC) stack. A recently developed low-temperature (LT) MSR catalyst (CuZnGaOx) was synthesized and tested in a designed reforming reactor. The experimental data show that at 200 °C the complete conversion of methanol is achievable with a hydrogen yield of 45 cm3 min-1 gCAT -1 . An experimental setup for measuring the characteristics of the integrated system was designed and used to measure the characteristics of the two-cell HT PEMFC stack. The obtained kinetic parameters and the HT PEMFC stack characteristics were used in the modeling of the integrated system. The simulations confirmed that the integrated LT MSR/ HT PEMFC stack system, which also includes a vaporizer, can achieve a thermally selfsustained working point. The base-case scenario, established on experimental data, predicts a power output of 8.5 W, a methanol conversion of 98.5%, and a gross electrical efficiency (based on the HHV) of the system equal to 21.7%. However, by implementing certain measures, the power output and the electrical efficiency can readily be raised to 11.1 W and 35.5%, respectively

Dissolution, Nucleation, Crystal Growth, Crystal Aggregation, and Particle Breakage of Amlodipine Salts: Modeling Crystallization Kinetics and Thermodynamic Equilibrium, Scale-up, and Optimization

Both in the pharmaceutical industry and in pharmacology, crystallization and dissolution processes play an important role in the production and physiological action of active pharmaceutical ingredients. For the first, recrystallization or other phase transformations present an indispensable step in downstream separation and purification processing, while for the second, solubility is of vital importance for drug delivery systems such as tablets. In the present study, the anhydrous form of amlodipine was investigated from its basic structural and conformational characteristics using molecular modeling, to the laboratory-scale formation of its solid phase from solution, and finally, to industrial-size operation by applying models, based on the hydrodynamic characteristics in the crystallizer due to mixing (computational fluid dynamics (CFD)), transport phenomena (specifically heat transfer), and population balance modeling. Simulations revealed that an efficient process intensification and control may be realized through the seeding and widening of the metastable zone (nucleus absence albeit supersaturation), providing a uniform and monodisperse size distribution

Dissolution, Nucleation, Crystal Growth, Crystal Aggregation, and Particle Breakage of Amlodipine Salts: Modeling Crystallization Kinetics and Thermodynamic Equilibrium, Scale-up, and Optimization

Both in the pharmaceutical industry and in pharmacology, crystallization and dissolution processes play an important role in the production and physiological action of active pharmaceutical ingredients. For the first, recrystallization or other phase transformations present an indispensable step in downstream separation and purification processing, while for the second, solubility is of vital importance for drug delivery systems such as tablets. In the present study, the anhydrous form of amlodipine was investigated from its basic structural and conformational characteristics using molecular modeling, to the laboratory-scale formation of its solid phase from solution, and finally, to industrial-size operation by applying models, based on the hydrodynamic characteristics in the crystallizer due to mixing (computational fluid dynamics (CFD)), transport phenomena (specifically heat transfer), and population balance modeling. Simulations revealed that an efficient process intensification and control may be realized through the seeding and widening of the metastable zone (nucleus absence albeit supersaturation), providing a uniform and monodisperse size distribution

Reactor conceptual design by optimization for hydrogen production through intensified sorption- and membrane-enhanced water-gas shift reaction

In this feasibility study, a novel industrial-scale reactor structure for continuous hydrogen production via intensified water-gas shift (WGS) reaction is proposed. It considers both trickling calcium-oxide sorbent for carbon dioxide removal (SOR) and Pd-based membrane for hydrogen separation (MEM). It is shown that WGS, SOR, MEM, and cooling can be decoupled with a special reactor superstructure mathematically represented with the pseudo-homogenous one-dimensional model. The final reactor structure and operating conditions are determined by using rigorous multi-objective optimization. Two objective functions take all main costs into account (total reactor volume and respective volumetric fractions for the catalyst, sorbent, and membrane) and the main benefit (hydrogen yield). The results show that the best cost-benefit relation can be achieved with the two-module reactor and combined WGS and SOR processes, with 95% carbon monoxide conversion (64% higher than the equilibrium conversion at the same conditions) and the outlet-stream containing only 0.7% of carbon dioxide