Experimental investigation of near-critical CO2 tube-flow and Joule–Thompson throttling for carbon capture and sequestration (original) (raw)
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Energy, 2020
The design of safe and cost-efficient CO 2-transportation systems is an integral part of CO 2 capture and storage (CCS) deployment. To achieve this, accurate transient flow models capturing the occurrence of gas, liquid and solid CO 2 are needed. These in turn rely on experimental validation. In this work, we present a new experimental facility designed to capture pressure and temperature during the depressurization of CO 2 and CO 2-rich mixtures in a tube at high spatial and temporal resolution. Experiments with pure CO 2 starting from both gaseous and dense (liquid) states are presented, and a reference experiment with N 2 is included. The experimental results for both pressure and temperature are analysed by comparison with predictions by a homogeneous equilibrium model. Emphasis is put on the decompression-wave speed, of particular relevance for running-ductile fracture in CO 2-transportation pipelines. We observe good agreement with predicted decompression-wave speeds in the single-phase region, and fair agreement for two-phase flows when the calculations are based on the assumption of equilibrium. However, the observed 'pressure plateau', a key factor in the prediction of running-ductile fracture, can be significantly lower than that calculated assuming equilibrium.
International Journal of Low-Carbon Technologies, 2010
Transcritical nature of the CO 2 refrigeration cycle makes the capillary tube behavior distinctly different compared with a conventional subcritical system. A novel closed-form analytical solution is proposed to simulate the flow characteristics of an adiabatic capillary tube. Such an analytical solution is being proposed, for the first time, for the transcritical-superheated-two phase region in a CO 2 -based transcritical heating -cooling system. Improved K value relations based on Gaussian function for CO 2 are obtained employing MATLAB-based tools. Predictions by the proposed analytical model have been validated against carefully obtained test data and the observed agreement is fairly good. Downloaded from https://academic.oup.com/ijlct/article-abstract/5/4/245/687892 by guest on 02 May 2020 P, pressure (bar); T cap,in , capillary tube temperature (K); _ m predicted , refrigerant mass flow rate (kg s 21 ). Cap tube 1: D ¼ 1.42 mm, L ¼ 1 m, 1 ¼ 0.00576 m. Cap tube 2: D ¼ 1.71 mm, L ¼ 2.95 m, 1 ¼ 0.00392 m.
A study of transcritical carbon dioxide flow through adiabatic capillary tubes
International Journal of Refrigeration, 2009
This paper advances a study of the transcritical expansion of carbon dioxide (R-744, CO 2) through adiabatic capillary tubes. The influence of both operating conditions (inlet and exit pressures, inlet temperature) and tube geometry (capillary diameter and tube length) on the CO 2 mass flow rate was experimentally evaluated using a purpose-built testing facility with a strict control of the measured variables. A dimensionless correlation to predict the refrigerant mass flow rate as a function of tube geometry and operating conditions was developed. In addition, a theoretical model was put forward based on the mass, energy and momentum conservation principles. The model results were compared with experimental data, when it was found that the model predicts 95% of the measured refrigerant mass flow rate within an error band of AE10%. The model was also employed to advance the knowledge about the transcritical carbon dioxide flow through adiabatic capillary tubes.
International Journal of Greenhouse Gas Control, 2021
To design and operate safe and efficient CO2-transportation systems for CO2 capture and storage (CCS), engineers need simulation tools properly accounting for the fluid and thermodynamics of CO2. As the transportation systems evolve into networks, it becomes important that these tools also account for impurities in the CO2, which may significantly affect the thermophysical properties, directly impacting system design and safety. Tube-depressurization experiments provide crucial data to develop and validate models describing transient multiphase multicomponent flow in pipes. In this work, we perform experiments in a new facility with dense and fast instrumentation for both pressure and temperature. One experiment is for CO2 with 1.8 mol % N2, and one has 1.92 mol % He, both starting from 12 MPa and 25 ∘ C. In order to quantify the effect of impurities, the experiments are compared to results for pure CO2 and analysed on the background of simulations. We employ a homogeneous equilibr...
An Experimental Investigation of Liquid CO2 Release Through a Capillary Tube
Energy Procedia, 2013
This experimental study was performed to investigate the flow characteristics in the pipe of the blow-down system. When a liquid CO 2 container is found to lose mechanical integrity, possibly by material or mechanical defects, the liquid inventory should be drained out rapidly for the purpose of safety by the so-called blow-down process. In the course of the blow-down, the liquid CO 2 experiences the state change into a two-phase mixture of vapor and solid before releasing into atmosphere. The release rate of blow-down is affected by the characteristics of phase change. , Temperature and pressure was measured in capillary tube passages representing blow-down flow lines and the location of phase change was inferred with the measured data. The experimental result shows that phase change occurs just before CO 2 flow is exposed to ambient air for any tube length of this study.
Two-phase pressure drop during CO2 vaporization in horizontal smooth minichannels
International Journal of Refrigeration, 2008
Pressure drop experiments for a natural refrigerant vaporization of CO 2 were performed in horizontal minichannels. The test section was made of stainless steel tubes with inner diameters of 1.5 mm and 3.0 mm and with lengths of 2000 and 3000 mm. This test section was uniformly heated by applying electric current directly to the tubes. Experiments were performed at inlet saturation temperatures of À10, À5 and 10 C, mass flux ranges from 200 to 600 kg m À2 s À1 and heat flux ranges from 10 to 30 kW m À2. The current study showed the significant effect of mass flux, tube diameter, and saturation temperature on the pressure drop. The experimental results were compared against 13 existing two-phase pressure drop prediction methods. A new pressure drop prediction method based on the Lockhart-Martinelli method was developed with 9.41% mean deviation.
Carbonate looping cycle for CO2 capture: Hydrodynamic of complex CFB systems
Energy Procedia, 2011
High temperature looping cycles, such as carbonation-calcination cycles based on calcium sorbents or chemical looping combustion are being developed and play an essential role in CO 2 capture technologies. Among proposed configurations, outstanding schemes make use of a number of interconnected fluidized beds and may operate at bubbling or circulating regime. Fluidized bed behaviour is well-known since they are included in many industrial applications, such as power plants and chemical industries. However, there is a lack of knowledge about their operation when more than one fluidized bed are coupled in the same system. One promising configuration for Ca-based sorption looping systems relies on the use of two circulating beds as carbonator and calciner and two bubbling beds acting as loop-seal valves. Many theoretical and lab experimental studies point out the need of large solid circulation in the system to reach high carbonation efficiencies. The control of this flow in complex CFB looping systems, where also internal recirculation exists in the risers, becomes a difficult task and deserves further studies to characterize them. The challenge to solve, through experimental tests and mathematical modelling, is finding a comprehensive control method to operate two circulating beds in turbulent regime and two bubbling sealing devices. Experimental results supporting high carbonation efficiency or feasibility in scaling-up solid circulation rates and inventories are needed to make the system more reliable. A lab-scale cold flow facility has been designed based on Glicksman's scaling rules and constructed in order to conduct experimental tests. The mechanical design of the facility and the choice of solid material, fluidizing gas and operating conditions should be such as to ensure the circulation of solids between reactors and the presence of solids inventory in the carbonator which are necessary to achieve high capture efficiencies. Operation of the system has been tested for a long number of hours under very different conditions. Measurements of circulation rate, static pressure, voidage profiles and standpipe height of solids have been used to identify trends in the hydrodynamic behaviour of the whole system while varying gas velocities in the risers, loop-seals, inventories in the reactors or size distribution of the particles. The circulation rates attained in the cold flow plant are comparable, after scaling-up, to solid flows in the loop which lead to high enough carbonation efficiencies of the system.