LEAP CO 2 Laboratory CO 2 mixtures test facility

LEAP CO 2 Laboratory CO 2 mixtures test facility

THE PROJECT AIM CO 2 flows made available by several capture techniques are contaminated with impurities and this affects the design and operations of the different phases of the CCS process: devices for CO 2 separation and purification compressors and transportation pipes CO 2 injection and migration in the geological formations of the storage fields Since mixtures behavior can significantly differs from pure CO 2, it is fundamental a correct comprehension of their properties. The LEAP test facility lab is conceived to make available sets of experimental data to calibrate the mathematical models used for predicting the thermodynamic behavior of CO 2 rich mixtures 2

CALIBRATION OF CUBIC EQUATIONS OF STATE Pure substance a R T RT 2 2 C C = Ω A b = ΩB α = α( T ω) p R, C pc Cubic EOS p = RT v b v 2 aα + ubv + wb 2 Mixture N b = i= 1 x i b i a = x x a a 1 Binary interaction parameters (in this case for Van der Waals mixing rules) need calibration on experimental data i j i j i j ( k ) ij 3

MAIN FEATURES OF THE FACILITY Operating capabilities: Pressure range: from 0 to 200 bar Temperature range: from 10 to 150 C temperature Chemical species currently handled: Carbon Dioxide Nitrogen OXYFUEL CO Oxygen 2 CAPTURE Argon Extension of this expected in the future to include acidic and fuel species 4

THE CO 2 MIXTURES TEST FACILITY A look inside the facility 5

PREPARATION OF THE SAMPLE MIXTURE Ar The sample mixture is prepared by introducing inside a pressure bottle the different chemical species drawn from dedicated gas supply lines. Species are loaded sequentially from the least to the most volatile O 2 N 2 CO 2 6

PREPARATION OF THE SAMPLE MIXTURE To precisely determine the composition of the sample mixture, the bottle is first drained by means of a vacuum pump, achieving a vacuum of about 5 Pa (absolute). The bottle is weighted, with an analytical balance having an accuracy of 1 mg and a maximum capacity of 1 kg. The bottle is weighted after every gas introduction, and the composition can be determined 7

PREPARATION OF THE SAMPLE MIXTURE A refrigeration circuit is needed to introduce liquid CO 2 inside the vessel and maximize the amount of fluid introduced. V3A V3B V0 V4 V2 CO2 PG V1 2.8 +0 DL VP P. Chiesa - rev. 11-05-09 8

THE EXPERIMENTAL EQUIPMENT (1/3) V1 V0 V2 156.82 11.4 DA DL2 V3B V3A 29.64 PC HP N2 75.36 DL1 DL3 2.8 +0 V10B V10A V4 LC PG1 80 TC1 60 bar VPT 260 bar 6 bar LPT 260 bar TC3 30 T2 PG2 V11 VP V5 T1 38 PP2 EH1 EH2 V12 V13 80 MT 38 V6 V6R V7 V8 V9 V9R VTD TC2 HE RD PP1 P. Chiesa - rev. 11-06-09 9 TB

THE EXPERIMENTAL EQUIPMENT (2/3) LIST OF ABBREVIATIONS DA: personal computer for data acquisition DL1: data logger 1 (temperature probes and pressure transducers) DL2: data logger 2 (vibrating tube densimeter) DL3: data logger 3 (Pirani gauges) EH1: electric heating resistance 1 (VPT block) EH2: electric heating resistance 2 (tubes heater block) HE: heat exchanger HP: hand pump LC: loading cell LPT: liquid phase pressure transducer MT: main thermostat PC: pressurizing cell PG1: Pirani gauge 1 PG2: Pirani gauge 2 PP1: platinum probe 1 (thermostated bath) PP2: platinum probe 2 (vibrating tube densimeter) RD: rupture disk T1: thermostat 1 (vibrating tube densimeter) T2: thermostat 2 (liquid phase pressure transducer) TB: thermostated bath TC1: thermocouple 1 (VPT block) TC2: thermocouple 2 (tubes heater block) TC3: thermocouple 3 (LPT block) VTD: vibrating tube densimeter VP: vacuum pump VPT: vapor phase pressure transducers 10

PC VTD MT LC T1 PG1 TB HP VPT VPT PG2 DL3 T2 DA DL2 DL1

DETAILS: THE BOTTLE V1 V0 V2 V3B V3A N2 HP V4 PC LC The pressure bottle is made of titanium and has a capacity of about 60 ml. A sliding gasproof seal separates the bottle in two cells: the loading cell contains the sample mixture pressurization cell contains pressurized nitrogen 12

DETAILS: THE MEASUREMENT CIRCUIT 13

DATA MEASUREMENT High accuracy in the measurements is required in order to minimize errors: Temperature of the main bath and inside the vibrating tube densimeter is measured by platinum probes with an accuracy of 0.03 C (over the whole measurement chain). Pressure is measured by means of piezoelectric pressure transmitters (GE Druck) with an accuracy of 0.01% of the read value, calibrated at the operating temperature (115 C and 10 C for vapor and liquid phase instruments respectively) in the laboratory by means of a system composed by an hydraulic pressure balance and a liquid/gas separator. 14

PRESSURE CALIBRATION SETUP 15

SCHEME OF THE PRESSURE CALIBRATION SETUP Pressure balance Liquid/gas separator VB VS1 VS2 V2 V1 V3B V3A V5 HP N2 To measurement MEASUREMENT circuit CIRCUIT Pressurizing circuit

DENSITY MEASUREMENT Density is measured by a vibrating tube densimeter (Anton Paar mod. DMA-HPM) formed by a hollow U-shape tube which is induced to an harmonic oscillation by an external force. It is characterized by a resonant frequency that is inversely proportional to the square root of its mass. Therefore, depending on the density of the fluid filling the cavity, the frequency changes. Upon calibration against a reference fluids (CO 2 and R134a), density as a function of frequency can be measured.

DATA ACQUISITION SYSTEM (1/2) Signals from the instruments are collected by: Agilent 34970A data logger (pressure and temperature signals) Anton Paar mpds 2000 V3 (frequency/density signals). 18

DATA ACQUISITION SYSTEM (2/2) A program in LabView environment has been developed to record data on PC from all the instruments present in the apparatus. 19

TEST EXECUTION The test on the sample mixture is aiming to measure pressure and density of a single phase fluid, along slow transients at fixed temperature The densimeter does not provide reliable measures when a twophase fluid is present. Fluctuation of the signal from the densimeter indicates the presence of a two-phase fluid Reliable measurements require a quasi-static evolution of the conditions inside the circuit: pressure change < 0.005 MPa/s With a 1 Hz acquisition frequency, it means that about ~10000 points are sampled for each isotherm 20

VAPOR PHASE TEST Starting from vacuum conditions, the fluid gradually fills the measurement circuit. The measurement circuit is kept at a given temperature by the main thermostatic baths (TB). The bath T1 keeps the vibrating tube densimeter slightly colder (ΔT=0.5 1 C) than TB, to be sure that the dew point is first attained inside the densimiter 21

LIQUID PHASE TEST Starting from high pressure conditions, the fluid is drained from the circuit. The measurement circuit is kept at a given temperature by the main thermostatic baths (TB). The bath T1 keeps the vibrating tube densimeter slightly hotter (ΔT=0.5 1 C) than TB, to be sure that the bubble point is first attained inside the densimiter 22

SUPERCRITICAL TEMPERATURE TEST In this case the whole test can be executed in a single pass. Two passes (from vacuum to high pressure, and then back to ambient pressure) are carried out for sake of measures reproducibility. 23

EXAMPLE OF SCOPE: BINARY DISTILLATION CURVE (1/2) pressure = constant 1 pressure temperature temperature vapor liquid 100% composition 100% A B The goal is the determination of a distillation curve (as that on the upper left) running isothermal experiments at given compositions 2 density pressure temperature = constant pressure temperature = constant pressure 3 100% composition 100% A B 100% composition 100% A B density

EXAMPLE OF SCOPE: BINARY DISTILLATION CURVE (2/2) 4 pressure T4>T3 T3>T2 T2>T1 5 pressure = constant temperature pressure = constant T4 temperature vapor T3 T2 6 liquid T1 100% composition 100% A B 100% composition 100% A B