Gas-liquid Separation System Research Articles

Separation of Dimethyl Sulfide from Wort by Multi-Layer Centrifugal Film Method.

Installing a separation device for undesirable volatile substances represented by dimethyl sulfide (DMS) in wort boiling systems is a common way to reduce the thermal stress and maintain the beer’s flavor stability (characterized by the thiobarbituric acid (TBA) value), but most of these separation devices need to provide additional vacuum or primary thermal energy. This research shows that it can produce self-evaporation that consumes its own sensible heat when wort is in the state of turbulent film. Therefore, a new gas-liquid separation system named the multilayer centrifugal film-forming device (similar to the spinning cone column (SCC)) is proposed, which can strengthen self-evaporation through wort turbulent film and create gas phase conditions for the separation of undesirable volatile substances. The results show that up to 91.6% of the content of DMS in wort could be significantly removed by centrifugal film self-evaporation. The TBA value of wort was reduced by more than 15%, and the wort was not found to be oxidized. Compared with the traditional boiling method, the multi-layer centrifugal film-forming device can significantly save primary energy consumption and reduce energy consumption by 216.4 kJ per liter of wort during the boiling and cooling process.

Modeling subsea gas-liquid separation using proxy for phase separation for pre-salt reservoirs with high GOR

Brazilian pre-salt oil fields include ultra-deep water reservoirs with high CO2 content and high gas/oil ratio (GOR). For these cases, large volumes of CO2-rich gas reach the topside facilities that present limited gas processing capacity. In this context, the production of the oil field is restricted to the maximum gas production capacity of these facilities. The use of a subsea gas-liquid separation (SGLS) and reinjection system may be a solution to boost oil production, as this strategy allows reinjecting part of produced gas directly from the seabed. In this study, we developed a methodology for modeling the subsea separation and reinjection process, which is integrated with a compositional reservoir simulator. A proxy based on an equation of state (EOS) was used for volumetric phase separation in the subsea separator. This approach eliminates the necessity of flash calculation at the SGLS conditions. The methodology makes it possible to assess the potential impact of implementing this technology from a reservoir management perspective. The modeling methodology is applied to a benchmark case (synthetic simulation model representative of a pre-salt reservoir) and evaluated the impact of the SGLS over total production. The results show that the SGLS technology can successfully boost oil production in the context of platform gas production restriction. As soon as the SGLS was implemented, an extended oil production plateau was achieved due to increased gas production capacity. We observed a significant GOR increment in produced fluids during the simulation as a result of gas recycling strategy. This increasing GOR caused the field production to be restricted by maximum gas production constraint most of the time, despite the SGLS implementation. A higher GOR also affects the SGLS performance, increasing the proportion of gas that becomes available for separation at subsea separator conditions. An economic analysis is presented, showing that the SGLS has the potential to increase the financial return of the project. The introduced methodology will enable the inclusion of the subsea separation process in future analyses, paving the way for feasibility assessments and optimization processes for cases in which the SGLS may be an alternative.

Compaction Simulator: A Novel Device for Pressure Experiments of Subsurface Sediments

Increasing overburden pressure is a key factor that alters the chemical and physical properties of soils and sediments. However, limited information is presently available on how aquifer compression impacts water quality. We introduced a novel compaction device, which is composited of four parts, including pressure simulator reactor system (PSRS), gas-liquid separator (GLS), automatic collector (AC) and composite control system (CCS). We conducted experiments at various pressures to test the functionality and outcomes of the device. In general, this device can be used to examine changes in water chemistry associated with aquifer compression resulting from compaction (overburden pressure) or groundwater overdraft.

Midinfrared Sensor System Based on Tunable Laser Absorption Spectroscopy for Dissolved Carbon Dioxide Analysis in the South China Sea: System-Level Integration and Deployment.

System-level integration of a midinfrared carbon dioxide (CO2) sensor system based on tunable laser absorption spectroscopy (TLAS) was realized for the analysis of dissolved CO2 in seawater, employing an interband cascade laser (ICL) centered at 4319 nm and a multipass cell (MPC) with an optical path length of 29.8 m. At a low measurement pressure of 30 Torr, three absorption lines of 12CO2 were selected to realize different measurement ranges and a 13CO2 absorption line was targeted for simultaneous isotopic abundance analysis of δ13CO2. The sensor system was compactly integrated into a standalone system with automatic operation for underwater field deployment, and the working process was controlled by a specially designed electrical system. A gas-liquid separator system was developed for CO2 extraction from water, and a pressure-control mechanism with two operation modes (i.e., static and dynamic modes) was proposed to make the sensor system applicable under a deep-sea environment. A series of experiments were carried out in the laboratory for performance assessment of the developed sensor system employed for the analysis of dissolved CO2 in water. The sensor was deployed for a field test for natural gas hydrates exploration at an underwater depth of 0-2000 m in the South China Sea, with the sensor operating normally during the deployment.

Continuous sliding control applied to subsea oil and gas separation

Due to the complexity and cost of maintenance in subsea environment, subsea equipments should be designed to be extremely robust. Thus, the robustness of sliding control is used to project a controller of liquid level inside subsea gas–liquid separator system. Subsea separation presents challenges related to nonlinearities of the dynamical system and disturbances on pipelines flow both changing their patterns along the years of operation. The present article proposes a controller capable of treating uncertainties regarding nonlinear effects based on distributed parameters. The controller deal with these uncertainties considering their bounded boundaries. Usual problems linked to the discontinuous control function generated by the sliding strategy are mitigated with a softened stabilization condition. Instead of determining the convergence of the liquid level to a specific point, the sliding control is used to stabilize the liquid level into a recommended operation zone. Inside of this zone, a sigmoid function is used to ensure the continuity and differentiability of control signal. Numerical simulations use characteristics method to represent the pipeline dynamics. Finally, it is presented a case of a trajectory tracking during a severe slug to show control performance.

Room-temperature Chelate Vapor Generation of Lead Using Ammonium O,O-Diethyl Dithiophosphate as a Chelating Reagent and Determination by Atomic Fluorescence Spectrometry in Environmental Water Samples.

A novel gas-liquid separator (GLS) system for chelate vapor generation (Che-VG) combined with AFS was developed for the determination of trace Pb. It was shown that Pb can form a volatile chelate by mixing of Pb with ammonium O,O-diethyldithiophosphate (DEDTP) in various aqueous solutions. Under the optimal conditions (frit pores of the GLS, 5 - 15 μm; solution pH, 6.7; DEDTP concentration, 0.4%; flow rate of the two feed solutions in the on-line mode, 1.2 mL min-1; and carrier gas flow rate, 150 mL min-1), the calibration curve was linear up to 100 ng mL-1 Pb. The limit of detection (LOD) was 1.1 ng mL-1. The relative standard deviation was 5.6% for eleven replicate determinations of 10 ng mL-1 Pb. The efficiency of Che-VG was estimated to be 12%, and the volatile Pb species was preliminarily studied by ICP-OES. This method was applied to determine trace Pb in water samples.

High efficiency gas-liquid separation system for pumped wells

Abstract Gas-liquid separation is a very common process in industrial plants, where often high Efficiency of Gas Separation (EGS) is demanded. In the upstream oil industry, gas separation is also crucial for the proper operation of Electrical Submergible Pumps (ESP). Recent studies report the excellent performance of a gravitational separator known as Inverted-Shroud separator (IS-separator). Laboratory results indicate that this kind of separator can achieve total gas separation for a wide range of operation conditions under continuous two-phase flow. The original intent is to use the IS-separator for downhole gas separation in oil production wells. However, by account of its simple design and relatively compact size, it may be suitable for using in industrial plants. In this paper, we present the IS-separator in details, including geometry characteristics and phenomenology. The equipment performance is also discussed. In addition, the challenges related to the deep understanding of the gas separation process inside the IS-separator and the possible practical solutions are outlined.

Critical evaluation of strategies for single and simultaneous determinations of As, Bi, Sb and Se by hydride generation inductively coupled plasma optical emission spectrometry

A systematic study of hydride generation (HG) of As, Bi, Sb and Se from solutions containing As(III), As(V), Bi(III), Sb(III), Sb(V), Se(IV) and Se(VI) was presented. Hydrides were generated in a gas-liquid phase separation system using a continuous flow vapor generation accessory (VGA) by mixing acidified aqueous sample, HCl and sodium borohydride reductant (NaBH4) solutions on-line. For detection, a simultaneous axially viewed inductively coupled plasma optical emission spectrometer (ICP-OES) was applied. Effects of the HCl concentration (related to sample and additional acid solutions) and type of the pre-reducing agents used for reduction of As(V), Sb(V) and Se(VI) into As(III), Sb(III) and Se(IV) on the analytical responses of As, Bi, Sb and Se were studied and discussed. Two compromised HG reaction conditions for simultaneous measurements of As+Bi+Sb (CC1) or As+Sb+Se (CC2) were established. It was found that choice of the pre-reductant prior to formation of the hydrides is critical in obtaining the dependable results of the analysis. Accordingly, for a As(III)+As(V)+Bi(III)+Sb(III)+Sb(V) mixture and using CC1, thiourea/thiourea–ascorbic acid interfered in Bi determination and hence, total As+Sb could be measured. If L-cysteine/L-cysteine–ascorbic acid were used, measurements of total Bi+Sb was possible in these HG reaction conditions. For a As(III)+As(V)+Sb(III)+Sb(V)+Se(IV)+Se(VI) mixture and using CC2, thiourea/thiourea–ascorbic acid and L-cysteine/L-cysteine–ascorbic acid influenced HG of Se but ensured total As+Sb determination. In contrast, heating a sample solution with HCl, although did not pre-reduce As(V) and Sb(V), assured quantitative reduction of Se(VI) to Se(IV). Finally, considering all favorable pre-reducing and HG conditions, methodologies for reliable determination of total As, Bi, Sb and Se by HG-ICP-OES were proposed. Strategies for single-, two- and three-element measurements were evaluated and validated, obtaining the detection limits (DLs) below 0.1ngg−1 and precision typically in the range of 1.4–3.9% RSD.

Fluid dynamics of horizontal air–water slug flows through a dividing T-junction

Experimental data from horizontal air–water slug flows were obtained in a test facility which was a 34mm internal diameter, 10m long Plexiglas pipe connected to the 90° branch arms from a T-junction. The test points were located on the flow pattern map in the proximity of the transition lines which separates different flow patterns. Capacitive probes with helical and concave plate sensors were used to quantify the dynamic liquid holdup in each branch. They were combined with Venturi nozzles+differential pressure transmitters in each outlet branch for measuring the two-phase mass flow rates. The dynamic characteristics of the slug flow splitting in a T-junction were studied from the acquired signals. Diaphragm straight-through type valves were used in the run and in the lateral branch arms to imitate equipments consuming the two-phase flow after the T-junction. This assembly can also be used as a gas–liquid separation system. The results showed different mechanisms acting on the slug flow division phenomenon. Liquid accumulation into the run branch, between the TJ and the control valve, caused more gas to come to the lateral branch.

The Software Design of a Gas-Liquid Separation and Metering System

On many occasions, gas phase and liquid phase of original mixture needed to be measured in the processes of petroleum, chemical, natural gas and other industry. A system of gas-liquid separation and metering were studied deeply in this paper. Kingview was taken as the software of the system. It realized dynamic show of the system state and generated various reports. Three of the functional modules were mainly introduced in the software design. The nucleus part of the system was the PID module. Its function was to regulate the aperture of the valve properly. The interface design of supervisory and report management is also described in detail. The testing on the spot has proved that system function and accuracy can meet the needs completely. The system has the characteristics of reasonable structure and stable performance. It provided a better solution to the means of gas-liquid separation.

Determination of some inorganic species of Fe, Mn and Cr by chemical vapor generation hyphenated with inductively coupled plasma atomic emission spectrometry

Generation of volatile species (CVG) from Fe2+, Fe3+, Cr3+, CrO4²ˉ, Mn2+ and MnO4ˉ ions by reaction with NaBH4 reductant in HCl, CH3COOH and citric acids using gas-liquid phase separation system and inductively coupled plasma atomic emission spectrometry detection (ICP OES) was reported. The optimized conditions were obtained using low concentrations of HCl (0.05‑0.075 mol L‑1) and NaBH4 (0.25-1.0% (m/v)). Volatile species were more effectively generated for lower oxidation state of the analytes. Detection limits of 10, 25 and 66 ng mL-1 were achieved for Mn2+, Fe2+ and Cr3+, respectively.

Simultaneous determination of trace lead, tin and cadmium in biological samples by a chemical vapor generation-four-channel atomic fluorescence spectrometry dual gas–liquid separator system

A novel, accurate, and precise method is described for simultaneous determination of trace lead (Pb), tin (Sn) and cadmium (Cd) in biological samples by chemical vapor generation (CVG) coupled with non-dispersive atomic fluorescence spectrometry. A chemical vapor generation dual gas–liquid separator system for Pb, Sn and Cd determination assembled with atomic fluorescence spectrometry was proposed. The system consists of two peristaltic pumps as the liquid driver, two gas–liquid separators and an atomic fluorescence detector. In the first gas–liquid separator system, the main Cd vapor and some SnH4 were carried out with reductant solution I, and in the second gas–liquid separator system, the main PbH4 and some SnH4 were carried out with reductant solution II. Cadmium vapor generation was based on hydrochloric acid, cobalt chloride, thiourea and KBH4 concentrations of the first system, SnH4 generation was based on hydrochloric acid and KBH4 concentrations, and PbH4 was based on hydrochloric acid, potassium ferricyanide and KBH4 concentrations of the second system. The operating conditions of the instrumentation were optimized, including the flow rates of carrier and shield gas. The conditions of chemical vapor generation for Pb, Sn and Cd were studied in detail. Under optimized experimental conditions, the blank signal was satisfactorily minimized, giving limits of detection of 0.071, 0.058 and 0.002 ng ml−1 for Pb, Sn and Cd respectively. The relative standard deviation (R.S.D.) was respectively 1.3%, 3.4% and 2.9% for 10 ng ml−1 of Pb, Sn and 2 ng ml−1 of Cd (n = 7). Finally, the proposed method was successfully applied to the simultaneous determination of Pb, Sn and Cd in a series of Chinese certified biological reference materials using simple aqueous standard calibration techniques, with analytical results in good agreement with the certified values.

Development of a silicon-based passive gas-liquid separation system for microscale direct methanol fuel cells

The design, fabrication and performance characterisation of a passive gas-liquid separation system is presented in this paper. The gas-liquid separation system is silicon-based and its fabrication is compatible with the existing CMU design of the microscale direct methanol fuel cell (DMFC). Both gas and liquid separators consist of staggered arrays of etched-through holes fabricated by deep reactive ion etching (DRIE). The gas separator is coated with a thin layer of hydrophobic polymer to substantiate the gas-liquid separation. To visually characterise the system performance, the gas-liquid separation system is made on a single wafer with a glass plate bonded on the top to form a separation chamber with a narrow gap in between. Benzocyclobutene (BCB) is applied for the low-temperature bonding. The maximum pressure for the liquid leakage of the gas separators is experimentally determined and compared with the values predicted theoretically. Several successful gas-liquid separations are observed at liquid pressures between 14.2 cmH2O and 22.7 cmH2O, liquid flow rates between 0.705 cc/min and 1.786 cc/min, and CO2 flow rates between 0.15160 cc/min to 0.20435 cc/min.