ISBN 9783843929899

978-3-8439-2989-9, Reihe Thermodynamik

Christina Vogelpohl
Measuring and modeling high-pressure gas solubility in temperature modulated solvent systems (Band 24)

176 Seiten, Dissertation Technische Universität Dortmund (2016), Softcover, A5

Zusammenfassung / Abstract

In the context of process intensification, the efficient economical realization of the hydroformylation of long-chain 1-alkenes like 1-dodecene with syngas (CO/H2) to n-aldehydes is an interesting challenge from an academic and industrial point of view. One promising approach is the application of thermomorphic multicomponent solvent (TMS) systems, which consist of at least one polar solvent (e.g. propylene carbonate (PC) or dimethylformamide (DMF)) and one nonpolar solvent (e.g. n-alkanes). For kinetic studies as well as for process design and optimization, the gas-liquid phase-behavior is of high interest. In order to be able to describe the gas solubilities in these complex systems, the gas solubility in all applied solvents as well as in the hydroformylation reactant (alkene) and product (aldehyde) have to be taken into account.

Thus, high-pressure gas-solubility data of carbon monoxide (CO), hydrogen (H2) and syngas (CO/H2 with a molar ratio of 1:1) in various solvents like n-hexane, PC, DMF, 1-dodecene, 1-octadecene, n-butanal, n-heptanal, n-decanal, n-dodecanal, and n/iso-tridecanal as well as in mixtures of these solvents like n-decane and DMF; n-decane and PC; 1-dodecene and n-dodecanal; 1-dodecene, n-decane, and DMF; 1-dodecene, n-dodecanal, n-decane, and DMF and 1-dodecene, n-dodecanal, n-decane, and PC was measured for temperatures between 295.2 K and 367.8 K and pressures up to 16.7 MPa. The experiments were performed in a high-pressure variable-volume view cell applying the synthetic method. For modeling and prediction of the gas solubility (H2, CO, and syngas (H2/CO)) in the considered solvents and solvents mixtures, the Perturbed Chain Statistical Associating Fluid Theory (PC-SAFT) was used. Binary gas/solvent systems investigated were modeled accurately by applying temperature-independent binary interaction parameters (kij´s), which were fitted to the binary gas/solvent systems. These kij´s could be used to predict the gas solubility of CO, H2, and syngas in pure solvents and their mixtures without further adjustments. The results show that PC-SAFT is able to predict ternary or higher systems consisting of pure gas/solvent mixtures, gas mixture/pure solvent and gas mixture/solvent mixtures with satisfactory accuracy. All considered systems can be predicted within an average absolute deviation (ARD) between experimental and calculated data of below 12 %.