Process intensification of multiphase flow and reaction system: Perspectives

Kinetic analysis of dehydrogenation reaction of cyclohexane catalyzed by Raney-Ni under multiphase reaction conditions

CFD-DEM simulation of fluorination reaction in fluidized beds with local grid and time refinement method

The development of pressure transient analysis was based on the assumption of a single phase slightly compressible fluid. This assumption was later relaxed to handle dry gas reservoirs and multiphase situations. The literature reported several methods for multiphase well test analysis [e.g., Perrine-Martin method (1956), pressure squared method proposed by A1-Khalifah (1987), and the two-phase pseudopressure function by Raghavan (1976), and 3-zone Fevang and Whitson approach (1995)]. In this paper, we develop new formulation for generalized multiphase pseudo-pressure and pseudo-time functions that can handle any type of multiphase flow system. In particular, the new formulation uses the modified black-oil (MBO) approach and can handle volatile oils and gas condensate reservoirs in more accurate ways than presented previously in the literature. These generalized multiphase pseudo-functions were validated through the analysis of many simulated drawdown and pressure buildup tests covering comprehensive inner (radial wells, partial penetration, fractured, and horizontal wells). The simulated cases also covered all multiphase flow situations. In every simulated case, analysis using the new functions was compared with single phase, Perrine-Martin, and the multiphase approaches proposed by Raghavan and Fevang and Whitson analyses. The new technique proved to be the most accurate among the other techniques. The new technique also uses one generalized form to handle any multiphase situation including volatile oils and gas condensates. As an example, application of the new generalized multiphase pseudo-functions to analyze transient data generated in gas-water multiphase flow system, at different water cut values; it was found that the new multiphase pseudo-function technique was able to predict the flow capacity with error percentage less than 10% when the water cut value was less than 50%. This was at least 2 folds better than other existing techniques. It was also found that this error percentage increased when the water cut value exceeded 80%. Applying the new pseudo-functions techniques also improves the quality of data for analysis in multiphase flow situations.

The formation and dissociation reaction rates and their kinetic behavior of propane gas hydrate (PGH) within the well-defined sediment particle's packing structures were experimentally investigated in this work by using a multi-phase heterogeneous reaction system, consisting of propane gas (g), water (l), PGH (s) and sediment particles (glass beads) (s). This work was carried out under the formation conditions of P = 0.427 MPa and T = 273.5 K, and under the dissociation conditions of P ≤ 0.168 MPa and T = 273.5 K.;A new designed, isothermal, and packed bed batch reactor was used for the kinetic analysis of the above defined PGH reaction system under the smooth operating conditions, yielding the satisfactory, reproducible material balance. Quantitative overall reaction rates of PGH formation and dissociation were derived and orders of the above reactions were experimentally obtained.

Gas hydrates porosity and effective volume under multiphase flow conditions

Multiphase flow phenomena are widespread in nature and production process. The study of the flow mechanism and characteristics are a very important in the multiphase pipe flow. The establishment of multiphase flow experimental devices and systems is necessary in the study. In order to multi-phase pipe flow simulation, the small-scale physical experimental system based on the PLC control, and the experimental simulation system of based on Configuration software design are achieved. The physical experimental system can be achieved signals acquisition and control. Bubble flow, stratified flow, wavy flow, slug flow and other flow patterns can be formed in the experimental pipeline by changing the oil-gas-water flow rate. The virtual experimental system consists of the control interface and virtual physical interface. The simulation experiments of the multiphase flow generation can be achieved through the data exchange by two computers. This system meets the requirements for multiphase flow experiment.

The paper deals with the modelling of multiphase flow and transport processes in porous media. The phases are water, NAPL (non aqueous phase liquids) and gas. In order to predict the complex processes of multiphase flow and transport, a deterministic numerical model was developed. This three-dimensional finite element model is able to simulate the simultaneous flow of all three phases. Furthermore the interphase mass transfer such as dissolution and volatilisation of the organic phase and the transport in the water and gas phase is taken into account. Additionally, transformation of pollutants due to adsorption and biodegradation in the solid phase is included in the model.

The catalytic hydrolysisof cellulose to produce 5-hydroxymethylfurfural(HMF) is a powerful means of biomass resources. The current efficienthydrolysis of cellulose to obtain HMF is dominated by multiphase reactionsystems. However, there is still a lack of studies on the synergisticmechanisms and component transport between the various processes ofcellulose hydrolysis in a complex multiphase system. In this paper,a liquid membrane catalytic model was developed to simulate the hydrolysisof cellulose and its further reactions, including the adsorption ofthe liquid membrane on cellulose particles, the consumption of cellulosesolid particles, the complex chemical reactions in the liquid membrane,and the transfer of HMF at the phase interface. The simulations showthe synergistic effect between cellulose hydrolysis and multiphasemass transfer. We defined an indicator () to characterize the sensitivity of HMFyield to the initial liquid membrane thickness at different reactionstages. decreased gradually when the glucose conversionincreased from 0 to 80%, and increased with the thickening of the initialliquid membrane thickness. It was shown that the thickening of theinitial liquid membrane thickness promoted the HMF yield under thesame glucose conversion. In summary, our results reveal the mechanismof the interaction between multiple physicochemical processes of thecellulose liquid membrane reaction system.

The primary task of rotary shaft seals is to prevent an unwanted fluid transfer between two areas. In shaft passages of gearboxes, for example, rotary shaft seals avoid the leakage of transmission oil to ambient air. This means the flow in the lubricant film in the sealing gap between the sealing edge and the shaft surface consists of at least two phases. Taking the phenomenon of cavitation into account, the flow consists of three phases. This study aims to provide an in-depth understanding of the multiphase flow in the lubricant film of rotary shaft seals. As experimental studies of the flow processes on a microscale have proven to be quite difficult, a simulation-based approach is applied. Computational fluid dynamics (CFD) serves to compute the transient multiphase flows in the lubricant film in the sealing gap. The computational domain is a three-dimensional microscale model of the lubricant film. The results show the transient hydrodynamic pressure buildup and the dynamic phase interactions during operation. This study provides far-reaching insights into the multiphase flow processes in the lubricant film in the sealing gap and simulation-based evidence of the lubrication and sealing mechanism of rotary shaft seals.

A computer-aided software-tool for sustainable process synthesis-intensification

Parametric modeling of transition tubes were implemented based on constant cross section area assumption along the main central routes on CATIA software. The key objective of modeling these similar structures is to provide more geometric configuration options and modifications of micro channels for multi phase flow systems. The modeling processes were parameterized and analyzed by CATIA “Generative Shape Design” module with the help of “Parameters” and “Relations” functions. The surface models are all designed in circular cross sections that are constrained in two ways: one is perpendicular to the main central routes of the tube for planar transitional junction, and another is, perpendicular to the sub-branch central routes for oblique transitional junction three dimensionally. Next work is emphasized on numerical simulation and experimental investigation with these geometric structures in a multi phase flow system.

Multiphase flow in pipe has been intensively investigated since the oneset of oil and gas transportation by pipelines. As flow assurance problems keep arising in recent years, pipeline design solutions are desired for multi-phase flow system. The algorithms have widely guided the design of stream transportation from offshore well head to onshore terminal or platform. Operators would always seek cutting platform number or shut-in producing marginal field whose reserves cannot justify the construction cost. An accurate design of multiphase flow pipeline system is by all means demanded. Traditional studies focus on gas-oil two-phase flow by deriving empirical or semi-empirical correlations that fit the experimental data. This study investigates a gas–oil–water three-phase pipe flow system. Starting from the momentum and mass conservation equations, force balance, and interaction relationships between different phases, we developed analytical solutions to estimate the pressure drop for stratified flow regime. This general approach can be applied to any gas-oil-water flowing systems. It provides a solid base for nodal analysis, pressure drop calculation for multiphase flow, artificial lift evaluation, etc. to help design and optimize production system. This work can be particularly useful for steady-state distance transportation.

This article investigates the two regime transition points for bubble columns with the so-called dual-bubble-size (DBS) model featuring the utilization of a stability condition to analyze the compromise between dominant mechanisms. Our previous work indicated that the second point could be reasonably predicted and physically interpreted by the DBS model for various gas-liquid systems. This work further clarifies the relationship between the bifurcation of energy dissipation and of structural parameters and the regime transition. It is found that the bifurcation of energy dissipation exists for both the gas-liquid and gas-solid systems and call be used to predict and understand regime transition in multiphase flow. Then the DBS model is incorporated into the two-fluid model for calculating interphase coupling, and I computational fluid dynamics (CFD) calculation is performed to simulate I bubble column. The shoulder on the gas hold-up curve can be observed in the simulation with the new coupling method, and the second transition point predicted from the CFD simulation is consistent with experiments and the calculation of the DBS model. Sparger effects are investigated through the two simulation cases for uniform aeration and local aeration, and the radial distribution of local hydrodynamic parameters is comparable with experimental data in the literature.

The research work analyses the relationship of 155 Process Intensification (PI) technologies to the components of the Theory of Inventive Problem Solving (TRIZ). It outlines TRIZ inventive principles frequently used in PI, and identifies opportunities for enhancing systematic innovation in process engineering by applying complementary TRIZ and PI. The study also proposes 70 additional inventive TRIZ sub-principles for the problems frequently encountered in process engineering, resulting in the advanced set of 160 inventive operators, assigned to the 40 TRIZ inventive principles. Finally, we analyse and discuss inventive principles used in 150 patent documents published in the last decade in the field of solid handling in the ceramic and pharmaceutical industries.

Perspectives on the process intensification of CO2 capture and utilization