Slug Length Research Articles

Slug flow characteristics of air-liquid two-phase flow in horizontal pipes over a wide range of liquid viscosities

A large number of studies have been conducted to understand the slug flow characteristics of air-liquid two-phase flow in horizontal pipes and to capture parametric trends of critical flow parameters associated with slug flow, such as the liquid slug length, elongated bubble length, and elongated bubble velocity. Based on these findings, many attempts have been made to develop empirical correlations to predict the slug flow parameters. However, the validity of these correlations is limited to a specific working fluid and narrow ranges of geometrical or operating conditions, thereby reducing their effectiveness as useful general predictive tools. This limitation has created a need to develop empirical correlations that offer high accuracy over a broad application range, i.e., a wide range of liquid viscosities, superficial liquid and gas velocities, and pipe diameters. In this study, two-phase slug flow experiments were performed to examine the hydrodynamic features of slug flow under two different pipe diameters (2 and 4 cm) and two different liquid temperatures (25 and 45°C). In addition, a new consolidated database consisting of 1563 slug flow data points was amassed from 16 sources, including the present experimental data, covering a wide range of operating conditions and fluid properties. In particular, this study includes various liquids with a wide range of viscosities, such as heavy oil, light oil, and water. The parametric study of air-liquid slug flow at various viscosity levels revealed that as the mixture velocity increases, the liquid slug length tends to decrease when the liquid viscosity is high and increase when the liquid viscosity is low. On the other hand, the elongated bubble length and elongated bubble velocity increase with increasing superficial gas velocity, regardless of the liquid viscosity. Based on these findings, three empirical correlations were developed to predict the liquid slug length, elongated bubble length, and elongated bubble velocity. These correlations provide excellent predictive capability against the consolidated database, with overall MAE values of 18.1%, 20.6%, and 9%, respectively.

Experiments on Slug Flow Dynamics in Helically Coiled Tubes

Slug flow characteristics in helically coiled tubes were investigated in experiments. Pressure loss, slug velocity, and slug passing frequency were measured using pressure transducers and backlight imaging of dyed water under illumination. For a 20-mm-diameter tube, parametric dependencies on gas and liquid volume flow rates for total superficial velocities of up to 6 m/s with three different radii of curvature (R = 0.270 m, R = 0.375 m, and R = infinity/straight tube) were explored. The main experimental results obtained are (1) the bubbly flow regime shrinks because of centrifugal acceleration from the coiled geometry, (2) the liquid slug length remains unchanged regardless of changes in gas and liquid flow rates, and (3) the pipe friction factor decreases with slug passing frequency.

A slug length calculation for a contraction with mean flow between two half cylinders

A slug length is widely used to describe additional mass inertia at low frequencies in duct acoustics. It is often used in acoustic energy analysis, e.g. as one of the inputs for semi-analytical or empirical models to obtain the acoustic reflection and transmission coefficients. However, the calculation of slug length is usually empirical and limited to many conditions, such as simple geometric configurations, low frequencies, no mean flow, etc. In this paper, the slug length at a contraction with mean flow between two half cylinders is calculated by different methods: solving the Laplace's equation both analytically and numerically, solving the Helmholtz equation, and using the Cummings - Fant equation based on the numerical results of frequency-domain linearized Navier-Stokes equations. Both the frequency-dependence and the mean flow effect are discussed. The calculated slug lengths are then used in the semi-analytical model to predict the acoustic scattering at tube rows in the presence of a cross mean flow.

Regulating the Gas–Liquid Slug Flow in Microchannels through High-Frequency Pulsatile Perturbations

The gas–liquid slug flow that is characterized with alternate formation of gas and liquid segments has been widely applied for chemical synthesis and analysis. For its applications, it is essential to precisely control the gas and liquid slug lengths. However, using the passive method, the bubble/droplet generation frequency and their sizes are influenced by multiple parameters including the channel dimension, fluid physical properties, the gas-to-liquid flow rate ratio, and so forth and hence lack control flexibility. In this work, an active approach using pulsatile perturbations to control the gas–liquid slug flow is demonstrated. A rotating valve is applied to produce a high-frequency pulsating air flow. Under its influence, either Taylor bubbles in a hydrophilic channel or liquid-in-gas droplets in a hydrophobic channel can be generated synchronously with the flow pulsation. Therefore, the gas and liquid slug lengths can be independently tuned via the air inlet pressure and the liquid flow rate, respectively. The maximum generation frequency is up to ∼1300 Hz. In addition, the effects of the pulsation frequency, the pulse duty ratio, and the liquid viscosity are also investigated. This technique provides an efficient method to regulate the gas–liquid slug flow in multiphase microreactors or microfluidic analytical systems.

An experimental investigation of the stochastic nature of slug flow

Slug flow is widely encountered in oil and gas systems. It has an unsteady hydrodynamic behavior that motivated the development of mechanistic models to better understand and quantify the parameters of the flow. The present work investigated several slug flow conditions through an experimental campaign that was performed in a 2-in ID horizontal pipe facility. The experimental data were statistically analyzed and they indicated the suitability of a lognormal distribution to model the flow characteristics, such as slug length, film length, and frequency. Based on the mean results, slug and film lengths tend to increase as more gas is present in the flow. The mean frequency indicated that higher frequencies are obtained with lower gas fractions. All the slugs from each test were individually studied using different approaches to analyze the data. The results suggest the existence of a relationship between the slug and film lengths when the slug unit is identified starting from a film region followed by a slug region. The values of the coefficient of determination for the relation between slug length and film length indicate a possible influence of other flow parameters of stochastic nature, such as slug liquid holdup, that could affect the behavior of the slugs.

Evaluation of the Effect of Elevation on Terrain-Induced Slugging in a Riser System

This work investigates the impact of elevation on terrain-induced slugging in a riser system. Fluid compositions were modeled with multiflash and exported to OLGA in a readable PVT Table File. Pipeline materials and properties with geometry of different elevation were modeled in OLGA to develop a flowline model. Two geometries (1 and 2) of different elevations were defined to establish their effect on accumulated liquid volume flow, surge liquid volume, slug length, number of slugs and slug density. The result shows that Geometry 1 with a total elevation(height)of 450 ft has a total liquid volume flow of 10.1058 ft3/s and Geometry 2 with a total elevation(height) of 300 ft has a total liquid volume flow of 0.197822 ft3/s for the same time of 2473.99 seconds. Also, Geometry 1 has a surge liquid volume of 543.4608484 ft3 at a drain rate of 0.20843960 ft3/s and Geometry 2 with a surge liquid volume of 210.7395 ft3 at a drain rate of 0.23892 ft3/s. There was no slug length and number of slugs in pipe of Geometry 1 while Geometry 2 has a slug length of 531.78 ft indicating severe slug in Geometry 2 system of different elevation. The slug density of Geometry 2 system was twice that of Geometry 1. Change in the elevation for the geometries has shown a significant effect on terrain–induced slugging in the pipe-riser system.

Prediction of slug length for high-viscosity oil in gas/liquid horizontal and slightly inclined pipe flows

The production and transportation of high viscosity liquid/gas two-phase Newtonian mixtures along petroleum production systems is a challenging operation due to the lack of understanding the flow behavior and characteristics. In particular, accurate prediction of two-phase slug length in pipes is crucial to efficiently operate and safely design oil well and separation facilities. The objective of this study is to develop a mechanistic model to predict high viscosity liquid slug length in pipelines and to optimize the proper set of closure relationships required to ensure high accuracy prediction. A large high viscosity liquid slug length database is collected and presented in this study, against which the proposed model is validated and compared with other models. A mechanistic slug length model is derived based on the first principles of mass and momentum balances over a two-phase slug unit, which requires a set of closure relationships of other slug characteristics. To select the proper set of closure relationships, a numerical optimization is carried out using a large slug length dataset to minimize the prediction error. Thousands of combinations of various slug flow closure relationships were evaluated to identify the most appropriate relationships for the proposed slug length model under high viscosity slug length condition. Results show that the proposed slug length mechanistic model is applicable for a wide range of liquid viscosities and is sensitive to the selected closure relationships. Results revealed that the optimum closure relationships combination is Archibong-Eso et al. (2018) for slug frequency, Wong (2003) for slug liquid holdup, Jeyachandra et al. (2012) for drift velocity, and Nicklin et al. (1962) for the distribution coefficient. Using the above set of closure relationships, model validation yields 34% absolute average percent error, outperforming all existing slug length models.

Hydrodynamics of aqueous two-phase systems (ATPS) in millichannels

Aqueous Two-Phase Systems (ATPS) have been recently employed for purification, concentration, synthesis, and separation of biomaterials and nanomaterials. Depending on the application, either parallel flow or segmented flow in microchannels is preferred. These ATPS are characterized by interfacial tensions, which are two orders of magnitude lower than typical organic aqueous systems. This results in only parallel flows in microchannels as the capillary numbers are high (Ca ≫ 3). Consequently, the flow observed here is stratified flow or core annular. The internal circulations in segmented flows in microchannels offer enhanced mixing. In the context of nanoparticle synthesis, this results in monodisperse particles. In this work, we show that Ca can be lowered to Ca≪1 by using a millichannel.In this work, we have studied the different flow patterns of ATPS (Polyethylene glycol 6000 -trisodium citrate system). Experiments were carried out in a milli-channel to span different flow patterns. Two cases were investigated i) the feed containing pure PEG and pure Citrate and ii) the feed containing the PEG-rich and citrate-rich solutions, which are at equilibrium. In the former case, there is a range of operating conditions when a single-phase flow is observed, while in the latter, we are always guaranteed a two-phase flow. The pattern formation was analysed and classified into three main categories, i.e., slug flow (interfacial tension dominated), transition flow, and core annular flow (inertia dominated). Flow regime maps based on the Reynolds number, Capillary number, and Weber number of each phase were found to be qualitatively similar to those of the Organic Aqueous System (OAS). Slug lengths and film thickness measured experimentally were validated with predictions of numerical simulation.

Experimental study of influence of liquid viscosity in horizontal slug flow

Slug flow is present in many industrial processes, including the ones related to the petroleum industry. Such flow pattern is characterized by the periodic passage of liquid slugs that may or may not be aerated and elongated bubbles that flow atop a liquid film. Most of the existing models for slug flow have been developed for two-phase water–air flows but, in oil and gas production, the liquid phase is often substantially more viscous than water. The aim of this article is to evaluate the effect of the liquid viscosity increase on slug flow. To achieve this goal, an experimental study on liquid–gas flows in a 26-mm ID, 8.65-m long horizontal pipe was developed. Water and mixtures of water and glycerin (μL≈5.46, 10.27, 15.39, 20.33 and 30.37 cP) made the working liquids. The experimental results from the high-speed camera and resistivity sensors enabled a detailed investigation of elongated bubble characteristics and slug flow parameters. The elongated bubble nose deformation, the appearance of plunging jets and the deformation of the dispersed bubbles are associated to dimensionless numbers. Experimental results show that the dispersed bubble deformation in the slug, the number of fragmented bubbles in the slug and the elongated bubble velocity increase as the mixture velocity and the liquid viscosity increase. The effects on the slug frequency and slug length depend on the superficial velocities of the fluids.

Investigation of bubble structure in a microchannel under microgravity conditions: Effects of discontinuous wettability with dynamic contact angle

A thorough understanding of the dynamics of bubble/liquid two-phase flows under microgravity conditions is essential for achieving efficient heat transfer between spacecraft and space stations. This paper examined the influence of the discontinuous wettability of a microchannel's wall on bubble structure movement under microgravity conditions. The volume-of-fluid methodology involving a dynamic contact angle code was employed by considering wall-adhesion equations to predict the form of the bubble/liquid interface at and near the wall. The flow field's governing equations were numerically solved utilizing the finite volume method. Initially, the results were compared to previously reported data for validation. Subsequently, the effects of discontinuous wettability with different configurations on the structure of bubbles were investigated; new insights were obtained into the size and shape of generated bubbles, as well as the slug length as a function of the wall wettability. The results showed that for a uniformly hydrophilic surface, the bubble had a concave shape under microgravity conditions, while for a uniformly superhydrophobic surface, the bubble had a convex shape. A microchannel wall surface with discontinuous wettability led to the generation of an asymmetric bubble, a variation in slug length, changes in the bubble's length and shape, and a continuous phase structure. Furthermore, variations in the wall wettability caused the flow upstream to vary and affected all four stages of bubble generation, namely lag, filling, necking, and the starting point of detachment.

Heat transfer analysis of immiscible slug flow-based microchannels: Study of channels with extended surfaces

Immiscible injection of slug(s) into a microchannel with square blocks attached to the bottom surface of the channel is studied using the phase-field approach for interface tracking. It is confirmed that immiscible injection enhances heat transfer by up to 85% compared to miscible injection considering identical thermophysical properties. The differences in the rate of heat removal between immiscible and miscible injection are explained by the hydrodynamics of the system. It is also found that larger injected slug size does not necessarily result in greater heat removal and causes the average Nusselt number to behave non-monotonically, reaching an optimum value at a specific slug length. This non-monotonic trend has been explained by analyzing the hydrodynamics of the system. The effect of the inter-block distance generally showed a monotonic increasing trend for the average Nusselt number, except for a single slug length. This behavior has been explained by the vorticity and Fourier transform analysis. An alternating slug injection configuration has also been analyzed. The analysis of this configuration reveals a non-monotonic behavior of the average Nusselt number vs the number of injected slugs. This non-monotonic behavior shows that for each value of the selected slug length, there is a critical number of slugs, and consequently, a critical slug length for which the average Nusselt number reaches a maximum. The hydrodynamics of the system justifies this non-monotonic behavior. Finally, the friction factor and performance evaluation criterion are presented as a guideline for the design of the microchannels based on flow configuration.

Prediction of maximum slug length considering impact of well trajectories in British Columbia shale gas fields using machine learning

In this study, the severity of slugging is assessed by predicting maximum slug lengths (MSL) quickly using the random forest (RF) algorithm based on the geometric features of well trajectories for a shale gas field. Severe slugging is one of the critical issues production engineering-wise because it causes operation shut-down. Thus it should be predicted for proactive measurements. A total of 5033 well trajectories were acquired from the northeastern area of British Columbia, Canada. The well trajectories are described using ten geometric features such as X, Y, and Z lengths in the Cartesian coordinate system, inclination, azimuth, and the other five. The 5033 well trajectories are grouped using the k-medoids clustering algorithm. The well trajectories in each group and the groups are compared visually to see if the ten features are representative enough to describe the geometric features of the well trajectories. The ten geometric features of the well trajectories are used as the input for RF, and MSL, which represents the severity of slugging, is used as the output for RF. The output data is simulation results by a pipe flow simulator, OLGA. The trained RF model provides the satisfactory prediction performance of MSL (R values, 0.866 and 0.857 for training and test data, respectively). In the trained RF model, X, Y, and Z lengths have the most significant importance among the ten geometric features. Because it is impractical to simulate all well trajectory scenarios by OLGA, the MSL values are projected onto a 3-dimensional map of which axes are X, Y, and Z lengths to visualize the trend of MSL. The 3-dimensional map showing the relation between MSL and the geometric features of well trajectories can be utilized as a quick reference to avoid severe slugging in designing well trajectories.

Investigation of particle flow characteristics in a CFB recirculation system using electrical capacitance volume tomography

Gas-solid fluidized beds have complex flow characteristics and opacity, and the particle motion characteristics in the recirculation system of circulating fluidized bed (CFB) have not been studied thoroughly. In order to study the motion of gas-solid two-phase flow in a CFB recirculation system, a 32-electrode electrical capacitance volume tomography (ECVT) system was developed with an imaging speed of 120 frames per second. Under various working conditions, the experimental platform of CFB was also built to measure the particle flow in the CFB recirculation system with the 32-electrode ECVT system, including the solid concentration and the flow velocity of particles in the branch pipe. When the velocity of fluidized gas U f is adjusted from 2.73 m/s to 1.76 m/s, the average solid concentration in the riser is roughly distribution of upper dilute and lower concentrated along the axial direction. With the decrease of U f , the average solid concentration generally showed an increasing trend, and the difference of solid concentration between different planes in the branch pipe gradually decreased. The slug length in the imaging area decreases, and the rising velocity of the slug in the riser above the branch pipe decreases. ECVT continuous images (U f = 2.73 m/s). • The 3-D solid concentration distribution in the CFB recirculation system was investigated. • ECVT continuous images under three different working conditions are given. • Solid concentration in the CFB recirculation system was acquired from the ECVT images. • Solid velocity was gained by analyzing the time lag of the neighbour planes.

Experimental investigation on flow-induced vibration of a flexible catenary riser conveying severe slugging with variable gas superficial velocity

A flexible catenary riser conveying gas–liquid mixture may experience the severe slugging induced vibration (SSIV) within a specific gas and liquid superficial velocity range. In this work, the SSIV of a flexible catenary riser with aspect ratio of 200 and a horizontal upstream pipeline was experimentally investigated to shed some light on the nonlinear multiphase flow-induced vibration and the correlation with the dynamic behaviour and the flow evolution. The non-intrusive optical measurement with high-speed cameras was employed to capture the vibration displacements of evenly distributed markers along the riser as well as the flow characteristics of gas–liquidmixture in the riser. The first and second types of severe slugging (SSI and SSII) were observed in the standard case (vsg = 0.177 m/s and vsl = 0.094 m/s) with an occurrence frequency ratio of 1:3. Large amplitudes are excited in the slug formation and gas blowout stages, and the latter presents more violent vibration with a faster travelling waves’ propagation speed. When the gas superficial velocity increases while maintaining the liquid superficial velocity, the transition stage is significantly elongated, characterized by the alternate appearance of partially filled gas–liquid mixture and short liquid slugs. Nevertheless, each liquid slug, no matter it is long or short, makes its contribution to the vibration response, presenting the coincidence of the recurrence frequency and the vibration frequency. The response amplitude is associated with the liquid slug length as well as the location of liquid inventory. The contributions of the three regimes (SSII, short liquid slugs and partially filled mixtures) are mainly associated with their occupied time. The severe slugging is the predominant contributor at vsg≤ 0.708 m/s, while its contribution is negligible at higher gas superficial velocities.

Effect of hybrid wall contact angles on slug flow behavior in a T-junction microchannel: A numerical study

This study investigates the effects of hydrophilic-to-superhydrophobic discontinuous wall contact angles on gas-liquid slug flow in a T-junction microchannel. The two-phase volume-of-fluid model with dynamic contact angle are used by solving wall-adhesion equations, which determine the shape of the fluid’s interface at and close to the wall. The governing equations of the flow field are solved numerically using a finite volume method. The obtained results are first validated against previously reported experimental data. Subsequently, the effects of changes in the wall contact angles on the slug flow behavior are examined resulting in the new insights into the size, shape, and velocity of slug flow as a function of the wall contact angle. Using a hydrophilic-superhydrophobic hybrid surface leads to the formation of an asymmetric bubble and separation of the bubble from the hydrophobic part. It also causes adhesion to the hydrophilic part, a change in slug length, a reduction in pressure drop, and a variation in the heat transfer characteristics and continuous phase structure. It is shown that using a particular pattern significantly increases the thickness of the liquid wall film.

Three-dimensional CFD analysis of liquid slug acceleration and impact in a voided pipeline with end orifice

ABSTRACT This research describes the dynamic behavior of an isolated slug driven by pressurized air in a voided line with an end orifice. A three-dimensional (3D) computational-fluid-dynamics (CFD) model is used to simulate the rapid propulsion and impact at the orifice for given slug length and driving air pressure, and is validated against experimental data. New mechanisms are observed: (i) the driving air pressure at the slug tail decreases with the slug motion; (ii) when the slug arrives at the orifice, the air fraction is almost one hundred percent in the most upstream part of the pipe, then it attenuates rapidly until an invariant eighty percent is achieved with a constant mass shedding rate; (iii) the velocity distribution in the radial direction of the cross-section at the midpoint of the slug length evolves from uniform to trapezoidal and then to logarithmic during slug movement; (iv) the initial vertical slug front changes its shape due to air intrusion at the top of the slug front; (v) the slug’s acceleration decreases first and then increases under the combined effects of its decreasing mass, nonlinear attenuation of the driving pressure, and increasing skin friction; (vi) the slug length has a constant rate of decrease.

Extractive desulfurization of model diesel fuel in a micro-channel contactor using deep eutectic solvents (DESs)

In the present study, the extractive desulfurization of model diesel fuel (i.e., dibenzothiophene (DBT) in n-decane) has been investigated using different deep eutectic solvents (DESs) in a micro-channel device. Eight different DES were synthesized using polyethylene glycol 200 (PEG200) and propionic acid (Pr) as hydrogen bond donor (HBD) in combination with four different hydrogen bond acceptor (HBA). The sulfur removal, slug length, specific interfacial area, and volumetric mass transfer coefficient were investigated for different examined DESs. In this regard, the hydrodynamic of the two-phase flow was captured using a camera and microscope. The remarkable sulfur removal of 62.16% and 75% was achieved using triethylamine/PEG200 with molar ratio of 1:3 (TEA/PEG200 [1:3]) and triethylamine/Pr with molar ratio of 1:3 (TEA/Pr [1:3]) in the residence time of 3.125 s, respectively. The highest sulfur removal in the micro-channel was 78.28% using TEA/Pr [1:3], which was achieved in the residence time of 25 s. The maximum value of the volumetric mass transfer for the extraction of DBT was 0.6097 s−1 using TEA/Pr [1:4] at a flow rate of 0.96 mL/min. It was found that the achieved sulfur removal in the micro-channel with very low residence time is comparable with the sulfur removal in the batch extraction with high operating time.

Taylor bubble formation and flowing in a straight millimetric channel with a cross-junction inlet geometry. Part I: Bubble dynamics

• Taylor bubble formation dynamics were studied at a cross-junction. • Filling and squeezing stage frequencies were not controlled by the same parameters. • Gas finger lengths were measured to identify different bubble pinch-off patterns. • A simple relationship linking relative bubble lengths with j G 0 / j L was established. The investigations of bubble formation dynamics at a cross-junction in a straight milli-channel were reported. The bubble formation process could be divided into the filling and squeezing stages, and their frequencies were compared at various conditions. It was found that the filling and squeezing frequencies were controlled mainly by the gas and liquid superficial velocities, respectively. The bubble formation frequencies could be related to the gas-liquid superficial velocity ratios, the liquid superficial velocities, and the bubble length. The bubble formation process was then analyzed considering the length of the gas finger right after the bubble pinch-off. Two patterns were identified depending on whether the pinch-off occurred inside of the cross-junction or not. The transition between these two patterns was described by a critical liquid Capillary number. Furthermore, the squeezing and dripping patterns were distinguished as the gas finger could fully block the channel or not. The transitions between the bubble formation patterns were determined by the gas Weber number and liquid Capillary number. Finally, the bubble length, the liquid slug length, and the bubble length normalized by the unit cell length could all be predicted based on the gas-liquid superficial velocity ratios η 0 .

Two-phase slug flow Lagrangian data analysis: Tracking unit-cell behavior across the pipeline with experimental data

Two-phase slug flow is frequently reported in oil production pipelines. Since reproducing oil extraction scenarios is usually not feasible, numerical models validated under bench scale conditions are often used to design pipelines. Even though slug tracking and slug capturing models, used in specific applications, usually evaluate data using a Lagrangian referential, experimental data based on sensors in test facilities is given in Eulerian referential coordinates. In order to establish a more consistent comparison between experimental data and numerical simulation and in turn to improve model validation, an alternative data analysis routine capable of analyzing data from a Lagrangian referential is proposed. The algorithm keeps track of unit cells across the pipeline in different measuring stations, monitoring changes in their hydrodynamic parameters. In order to demonstrate the capabilities of the developed procedure in this paper, the behavior and relation between slug length and bubble velocity is investigated from a Lagrangian referential. Even though average values and standard deviation were reported to remain approximately constant, slug length was found to oscillate at all times, which was also found to be linked with bubble oscillatory movement.

Effect of solvent on CO2 absorption performance in the microchannel

The absorption performances of CO2 into 2–amino–2–methyl–1–propanol (AMP) solutions mixed with solvents water, ethylene glycol (EG), diethylene glycol (DEG), and triethylene glycol (TEG) were investigated and compared in a T–junction microchannel. The absorption rate under different liquid flow rates (10–40 ml·h−1), gas/liquid flow rate ratios (0.5–10) and AMP concentrations (0.2–0.8 mol·L–1) was determined by the online photographic method. The dynamics (bubble and slug lengths, film thickness, recirculation frequency in slug, film–slug exchange and pressure drop) in the slug–flow region were analyzed and discussed. The results show that solvents affect the absorption rate with the order of AMP–water < AMP–EG < AMP–DEG < AMP–TEG, which is opposite to their solubility. The increased pressure drop and shorter bubble surrounded with thicker film are the dominant factors affecting the absorption rate, which increase the concentration driving of CO2 and film–slug mass exchange at the higher solvent viscosity respectively. Under current conditions, water is a good solvent candidate by joint consideration of absorption rate and energy consumption. This study provides guidance for solvent selection and manipulation of CO2 absorption in the microreactor.