Mass transfer and chemical reaction in gas-liquid-liquid systems

Gas-liquid-liquid reaction systems may be encountered in several important fields of application as e.g. hydroformylation, alkylation, carboxylation, polymerisation, hydrometallurgy, biochemical processes and fine chemicals manufacturing. However, the reaction engineering aspects of these systems have only been considered occasionally. For systems with very slow reaction kinetics this is not surprising, as the three phases will be at physical equilibrium. In reaction systems with fast parallel and consecutive reactions the effects of mass transfer and mixing on the product yield can be significant. A fascinating example of such a reaction system is the Koch synthesis of Pivalic Acid. In this work this reaction system was chosen as model system to study these effects

Post-Combustion CO2 capture using supported amine sorbents: A process integration study

We have evaluated the feasibility of supported amine sorbents (SAS) for their application in post- combustion CO2 capture. For this, the energy efficiency of a power plant equipped with a supported amine based capture facility is compared with the energy efficiency of a power plant equipped with a standard MEA-capture facility using the Spence®software tool developed by DNV-KEMA. Based on the simulations performed, application of a SAS-based capture facility at a natural gas combined-cycle (NGCC) plant is potentially 19% more energy efficient than a MEA-capture facility. For a pulverized- coal (PC) plant, the SAS-based plant could save up to 32% of the energy required in the MEA proces

Model for the sulfidation of calcined limestone and its use in reactor models.

A mathematical model describing the sulfidation of a single calcined limestone particle was developed and experimentally verified. This model, which includes no fitting parameters, assumes a calcined limestone particle to consist of spherical grains of various sizes that react with H2S according to the classic shrinking-core model. The initial size distribution of the grains is derived from mercuiy porosimetiy. The transport of H2S through the bidisperse limestone particle is calculated based on the randompore model of Wakao and Smith, which distinguishes macropore and micropore zones. Knudsen diffusivity inside the micropore zones is calculated according to the dusty-gas approach. The single-particle model delivers the value of a new defined utilization factor, which includes effects of external mass-transfer limitation, pore-diffusion limitation, and grain-size distribution on particle reactivity. A correlation derived for a single batch of calcined limestone explicitly expresses this utilization factor as a function of conversion and relevant process parameters. This correlatiori can be easily incorporated into reactor models, as shown for an existing model describing the capture of H2S by a fluidized bed of calcined limestone particles

A novel condensation reactor for efficient CO2 to methanol conversion for storage of renewable electric energy

A novel reactor design for the conversion of CO2 and H2 to methanol is developed. The conversion limitations because of thermodynamic equilibrium are bypassed via in situ condensation of a water/methanol mixture. Two temperatures zones inside the reactor ensure optimal catalyst activity (high temperature) and full conversion by condensation at a lower temperature in a separate zone. Due to this full gas conversion there is no need for an external recycle of reactants. Experimental work confirmed full carbon conversion (>99.5%) and high methanol selectivity (>99.5% on carbon basis). Additionally, it was shown that due the temperature gradient inside the reactor significant reaction rates are achieved under natural convection conditions

Solubility of CO2 in Aqueous Solution of Newly Developed Absorbents

The solubility of CO2 in various aqueous amine based solvents was determined at lower CO2 partial pressures. Cyclic capacity of various potential aqueous amine based solvents at 10 kPa CO2 partial pressure was determined by performing CO2 absorption at 30 ∘C, regeneration at 90oC and at 1 atmosphere. 1,7-Diaminoheptane and 1,6-Hexanediamine, N,N’-dimethyl was found to be having high cyclic loading of 0.81 and 0.85 moles CO2/moles amine respectively. Aqueous solution of 1,6-Hexanediamine, N,N’-dimethyl of 0.5 and 2.55 Mole/L concentration was selected for solubility study of CO2 at different partial pressure ranging from 1 up to 40 kPa, 30 ∘C and at 1 atmosphere. The solubilities of CO2 in aqueous 1,6-Hexanediamine, N,N’-dimethyl at 30oC were compared with those in aqueous solution of MEA with similar solution concentrations. The solubility of CO2 in 2.55 Mole/L 1,6-Hexanediamine, N,N’-dimethyl was found to be higher when compared to the 2.5 Mole/L MEA at lower CO2 partial pressure