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This study investigates the diluent-dependent diffusion flames of an axisymmetric methane jet in annular hot coflow (JHC) of oxidizer diluted by “inert” N2, CO2, and H2O, respectively. The fuel jet...

This numerical study investigates combustion characteristics of a CH4 jet flame in hot oxidant coflow (JHC) diluted by H2O versus the case by N2. Both MILD oxy–fuel combustion and traditional combustion are generated by varying the coflow oxygen level from 3% to 85% in volume. To distinguish physical and chemical effects of changing the diluent from N2 to H2O, the JHC flame diluted by XH2O (artificial H2O without reactivity) is also simulated. It is demonstrated that both the temperature and the dimension of the JHC flame reduce substantially when changing the diluent from N2 to H2O. Such reductions derive primarily from different fluid properties of N2 and H2O, i.e., H2O has a lower fluid density and a higher thermal capacity. The change from N2 to H2O is also found to have an impact more chemically on formation of the main intermediate species (i.e., H, O, CO, OH) and simultaneously to increase the flame lift-off distance due to longer ignition delay. Hence, the MILD combustion is expected to occur more...

The technology of natural gas dehydration with ionic liquids (ILs) as a promising method was proposed and systematically investigated in this work. The IL [EMIM][Tf2N] was screened out as an appropriate absorbent from 252 IL candidates for the natural gas dehydration process by means of the COSMO-RS model. The σ-profiles and σ-potentials of the CH4-H2O-IL system were analyzed at the molecular level to explain the possibility of CH4 dehydration using [EMIM][Tf2N] as absorbent. The experiment data of CH4 solubility in pure IL and in the mixture of IL + H2O were measured and compared with the predicted results by the UNIFAC–Lei model. Moreover, the CH4 dehydration experiment was carried out, and the gas product with a low water content (down to 350 ppm in mole fraction) can be obtained. Finally, the conceptual dehydration process was simulated and optimized using the rigorous equilibrium (EQ) stage model, into which the UNIFAC–Lei model parameters were input. It was found that the CH4 dehydration process wit...

In this work, the solubility and liquid-phase mass transfer coefficient of hydrogen (H2) in catalytic diesel at temperatures (353.2–453.2 K) and pressures (1–6 MPa) were measured experimentally. The solubility increases with the increase of pressure and temperature, and the Henry’s constant follows the relation of ln H (MPa) = 2447.02/T (K) – 0.11 with temperature. The molar fraction of H2 and system pressure at different equilibrium time were measured to estimate the liquid-phase mass transfer coefficient, and the results showed that with the increase of pressure the mass transfer coefficient increases. Furthermore, the solubility of H2 in diesel was predicted by the COSMO-RS model using six virtual model compounds. Both the experimental data and predicted values agree well. Then, the solubility of H2 in several hydrocarbon components with the same carbon atom but different ratios of C to H atoms was also predicted, and the results showed that the solubility decreases with the increase of the degree of u...

This work deals with the improvement of the current process of alkylation of benzene (B) with propylene (P) to produce cumene (IPB). Due to high energy consumption brought by high feeding molar ratio of benzene to propylene (B/P), an optimized process design has been developed and is presented. First, a side-stream was added to the diisopropylbenzene (DIPB) distillation column in order to recover some trisopropylbenzene (TIPB), resulting in a decrease of the energy consumption per product. The total heat duty on condensers and reboilers per product decreased by 5.5 and 4.3%, respectively. On the other hand, if the original fixed-bed reactor is replaced by a bubble-point reactor, the total heat duty on condensers and reboilers will decrease by 18.5 and 22.8%, respectively. Using the above two schemes together, they decreased up to 19.4 and 23.6% per product, respectively. Then, using a fixed-bed catalytic distillation (FCD) column for producing cumene, the calculated results showed that a much lower energy...