DEVICE FOR EXTRACTING GASEOUS AND LIQUID PRODUCTS FROM A REACTION FLUID

Abstract

It is provided a device and method for extracting gaseous and liquid products from a reaction fluid, in particular from an electrochemical reaction systems.

Claims

1. A device for extracting gaseous and liquid products from a reaction fluid, in particular from an electrochemical reaction systems, comprising at least one inlet for a flow of a reaction fluid comprising dissolved gaseous reaction products and liquid reaction products to be analyzed into the device, at least one outlet for a flow of a fluid depleted of said gaseous reaction products and liquid reaction products out of the device; at least two compartments, wherein a first compartment is configured for separating the gaseous reaction products from the reaction fluid using a first membrane supported on a porous material, and a second compartment is configured for subsequently separating the liquid reaction products from the reaction fluid using a second membrane supported on a porous material, wherein the first and the second compartment are connected by an extended capillary tube system, wherein the capillary tube system is configured to guide the reaction fluid from the inlet into the first compartment for contacting the first membrane for separating the gaseous reaction product from the reaction fluid and subsequently into the second compartment for contacting the second compartment for separating the liquid reaction product from the reaction fluid; wherein each of the at least two compartments is connected to a corresponding vacuum source for applying a vacuum to the first and second membrane, respectively, for transferring the flux of gaseous reaction products and liquid reaction products through the corresponding first or second membrane into the vacuum for further analysis, in particular MS analysis.

2. The device according to claim 1, wherein the first and second compartment are aligned along one same axis.

3. The device according to claim 1, wherein the first and second compartment are arranged inversely or back-to-front along the same axis.

4. The device according to claim 1, wherein each of the two compartments comprise a first ring with an opening and a second ring with an opening, wherein in the opening of the first ring a round piece/ disc with an inserted / incorporated capillary tube system is arranged and in the opening of second ring the respective porous material is arranged.

5. The device according to claim 4, wherein the respective first or second membrane is placed between the first and the second ring.

6. The device according to claim 4, wherein second ring is provided with a connection to the vacuum source.

7. The device according to claim 1, wherein a disc with the at least one flow inlet and the at least one flow outlet is arranged between the first and the second compartment, in particular between the first ring of the first compartment and the second ring of the second compartment.

8. The device according to claim 1, wherein the first and second membrane is made of PTFE, PEEK, PVDF, Silicone, or a film or thin layer directly deposited on the porous material.

9. The device according to claim 1, wherein the first membrane in the first compartment has a porosity between 10 and 30 nm, preferably 20 nm and a thickness between 100 and 200 .Math.m and the porous material, for example a frit, in the first compartment has porosity between 0.3 and 0.8 .Math.m, preferably 0.5 m and a thickness between 2 and 6 mm, preferably 4 mm.

10. The device according to claim 1, wherein the second membrane in the second compartment has a porosity between 30 and 80 nm, preferably 50 nm and a thickness between 100 and 200 .Math.m and the porous material, for example a frit, in the second compartment has porosity between 5 and 15 .Math.m, preferably 10 .Math.m and a thickness between 2 and 6 mm, preferably 4 mm.

11. A method for extracting gaseous and liquid reaction products from a reaction fluid using a device according to claim 1 comprising the steps: feeding a reaction fluid comprising dissolved gaseous reaction products and liquid reaction products to be analyzed into the device through at least one inlet into the first compartment; separating the gaseous reaction products (to be analyzed) from the reaction fluid in the first compartment using a first membrane supported on a porous material, subsequently separating / evaporating the liquid reaction products (to be analyzed) from the reaction fluid in the second compartment using a second membrane supported on a porous material, transferring the flux of gaseous reaction products and liquid reaction products through the corresponding first or second membrane into the vacuum for further analysis, in particular MS analysis, and guiding a flow of a fluid depleted of said gaseous reaction products and liquid reaction products out of the device through at least one outlet.

12. The method according to claim 11, wherein the pressure in the first compartment is between 5 and 15 mbar, preferably 10 mbar, and the Inlet pressure in the second compartment is between 50 and 150 mbar, preferably 100 mbar.

13. The method according to claim 11, wherein the vacuum applied is between 10.sup.-2 and 10.sup.-3 mbar.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The proposed solution is described in the following in more detail with reference to the figures.

[0056] FIG. 1 shows a view of the separating device according to the solution.

[0057] FIG. 2 shows a view of one separation layer of the device according to the solution.

[0058] FIG. 3 shows a view of the flow through the capillary system of the device according to the solution.

[0059] FIG. 4 shows mass fragments for m/z 2 recorded during the hydrogen evolution reaction using the device according to the solution.

[0060] FIG. 5 shows mass spectrum of products obtained during Electroreduction of CO.sub.2 on Oxide derived copper electrode.

[0061] FIG. 6 shows simultaneously recorded cyclic voltammograms and mass fragments.

[0062] FIG. 7 shows mass spectrum of products obtained during Electro-oxidation of HCO.sub.3-species on Gold and/or Nickel deposited electrode.

DETAILED DESCRIPTION

[0063] FIG. 1 is an explosion view of the two-layer compartment separator of gas and liquid products from incoming reaction fluid according to the solution. As illustrated in FIG. 1 a first compartment (or chamber) is configured for separating or extracting the gaseous ptoducts from the reaction fluid and a second compartmnet (or chamber) is configured for separating or extracting the liquid products from the reaction fluid. Each comparment comprises a set of membrane ans frit porous material. Each compartment is in communication with a vaccum side. In the right corner of FIG. 1 the assembled collector is illustrated.

[0064] In FIG. 2 one separation layer or compartment is presented in detail showing the components of one of the sides of the evaporator. FIG. 3 illustrates the flow of the reaction fluid through the capillary system of the device according to the solution.

[0065] As illustrated in FIGS. 1 and 2 each of the two compartments comprise a first ring with an opening and a second ring with an opening. The diameters of the first and second ring are approx. the same.

[0066] The opening of the first ring houses a round piece or disc type piece with an inserted or incorporated capillary tube system is arranged (capillary tube system is worked into the material of the round piece or disc)

[0067] The opening of second ring houses a frit porous material. The first or second membrane is placed between the first and the second ring. Thus, thus the membrane is sandwiched or interposed between the first and second ring. The membranes may be made of PTFE, PEEK or PVDF. The first membrane of the first compartment has porosity of 20 nm and thickness of 200 to 100 micrometers and frit with thickness of 4 mm and porosity of 0.5 micrometers. For second side, the membrane layer and frit is composed by a membrane with porosity of 50 nm thickness of 200 to 100 micrometers and frit with thickness of 4 mm and porosity of 10 micrometers.

[0068] A further disc (having approximately the same diameter as the first and second ring) is arranged between the first ring of the first compartment and the second ring of the second compartment. Said disc comprises a flow inlet and a flow outlet. The Inlet and outlet capillaries are incorporated or worked into the disc material. Inlet and outlet capillaries of the disc are in communication with the capillary system of the round piece / disc inserted into the opening of the first ring of each compartment.

[0069] The first and second compartments are aligned back-to-front along the same axis. The second ring of each compartment is provided with a connection to the vacuum source.

[0070] The compartments including the rings, discs and membranes with frit porous material are enclosed by an insulation cover. The insulation cover may comprise a sleeve that houses the compartments and two plates (with openings for the connection to the vacuum sources) that are closely attached to sleeve ends. The Insulation cover is made of PMMA material and two plates made of stainless steel.

[0071] The extended capillary system is now further described in more detail (FIGS. 2 and 3). The inlet capillary distributes the incoming flow of the reaction fluid to two horizontal capillaries. Each of the two horizontal capillary (i.e. parallel to the membrane) is connected in turn to two vertical capillaries (i.e. vertical to the membrane) with openings at the membrane corners. The membrane is connected with capillary tubes. Thus, the incoming flow is distributed to four capillaries that are in communication with the membrane, in particular four corners of a membrane. The four vertical capillaries promoting turbulent flow over the interface of the membranes. The incoming reaction fluid flows from the membrane corners over the membrane surface to the center of the membrane. While the reaction fluid flows over the first membrane the gaseous reaction product is separated through the membrane into the vacuum system. In the center of the (first) membrane is another capillary to guide the fluid depleted from gaseous products from the first compartment to the second compartment. In the second compartment the arrangement of the capillary system is basically the same as in the first compartment (mirror image). In the second compartment the reaction fluid (now depleted from the gaseous products) is guided through the inlet capillary, two horizontal capillaries and four vertical capillaries over the second membrane, and the liquid reaction products are separated or evaporated from the reaction fluid into the vacuum system. The reaction fluid now depleted of the gaseous and liquid reaction products flows through the outlet out of the device.

Example 1□

[0072] Detection time is crucial for studying the electrochemical reaction. The gas collector is able to detect H.sub.2 gas, at differential periods of around 100 millisecond range, as presented in FIG. 4. Such highly sensitive measurement allows to evaluate the reaction kinetics, despite the undesired liquid media interface at MS. The intensity of MS signal results from the applied electrochemical charge. Short period of reaction also represents low intensity signals. Nevertheless, the catalytic reaction has limited detection possibility at time range within 50 ms, where signals are at noise level of detection.

[0073] FIG. 4 shows mass fragments for m/z 2 recorded during the hydrogen evolution reaction resulting from step of potential with a defined duration of steps, during electro-reduction process of instantaneous hydrogen evolution at the Pt catalyst (metal disk) Ø5mm Electrolyte: 0.05 M H.sub.2SO.sub.4.

Example 2

[0074] High signal intensity and multiple products detection when CO.sub.2 is used as reactant during electrochemical reduction process for direct conversion to hydrocarbon molecules. In FIG. 5 are presented the main gas products, such as methane, ethylene and CO or liquid products like ethanol, acetaldehyde, acetone and allyl alcohol. The extractor system was able to separate the gas and liquid products from the electrolyte solution at high speed to clearly differentiate the potential of starting product evolution.

[0075] FIG. 5 shows the electroreduction of CO.sub.2 on Oxide derived copper electrode, electrochemical current - i.sub.F (red line); mass sepctrum current for gas products with hydrogen (grey line), carbon monoxide (green line), ethylene (violet line) and methane (blue line); mass spectrum current for liquid products with ethanol (orange line), acetaldehyde (orange line), acetone (green line) and allyl alcohol (red line). Conditions: 5 mV.s.sup.-1 in 0.1 M KHCO.sub.3. Saturation of electrolyte flowing at speed 12 .Math.L.s.sup.-1. Ion source set in “neg” with ion source standard calibration pre-measurements. SEM voltage was set at 1050 V and every mass was recorded simultaneously with Dwell time 100 a.u., resolution 50 and pause time 1. Capillary flow 2 .Math.L.s.sup.-1.

Example 3

[0076] The most important achievement is represented by the detection of liquid products, which is done at significant time resolution. The evaporation of liquid products into the vacuum system is achieved in part due to the flexibility of the combination of the hydrophobic PTFE membrane and the frit porous material for membrane support. The other important achievement is high MS signal intensity due to high flow of analysis gas into the MS, by combining two differential pumping stages, one dedicated to the gas and liquid collector and the second for MS analysis. Two pumping stages make it possible to allow many combinations of hydrophobic membrane porosity. Due to the high volatility of methanol, analysis of MS during a methanol oxidation reaction as in FIG. 6A is only possible by combining the right set of membrane and frit porous material. Also, in FIG. 6B is presented the CO.sub.2 formation during the oscillatory electro-oxidation of methanol on platinum. Such reaction conditions are only attained in stable reaction conditions at reactor cell, in part achieved using the seamless design of the capillary tube.

[0077] FIG. 6A shows simultaneously recorded cyclic voltammograms and mass fragments for carbon dioxide m/z 44, methyl formate at m/z 60, carbon monoxide at m/z 28 and methane at m/z 15, during electro-oxidation of methanol on 20 wt% platinum-nanoparticle catalyst supported on Vulcan drop coated in Ø5 mm glassy carbon. Conditions: 10 mV.s.sup.-1. FIG. 6B shows Period-one potential time series (red line) during electro-oxidation of methanol at 0.5 M H2SO4 and 1 M of methanol accompanied by mass fragments of carbon dioxide at m/z 44 (green line) in 20 wt% platinum-nanoparticle catalyst supported on Vulcan drop coated in Ø5 mm glassy carbon.

Example 4

[0078] The high vacuum regime under the membrane allows for fast extraction of converted unstable chemicals in solution, this is important to extract substances with low chemical stability or substances with no vapor pressure. A membrane coated with a catalytic active material such as Gold and Nickel is submitted to a high oxidative potential promoting an oxidation reaction to volatile MS detectable compounds. The reaction of non-detectable MS species like ionic dissolved compounds such as bicarbonate. The coated membrane is submitted to an oxidative potential using a power supply or a potentiostat instrument, which converts the ionic compounds to gaseous or volatil species such as CO.sub.2. The cathode is an immersed platinum wire with thickness 0.5 mm placed at the outflow of liquid.

[0079] FIG. 7 shows mass spectrum signals of resulted m/z 44 CO.sub.2 (orange line) and m/z 32 O.sub.2 (purple line) products during electro-oxidation of 0.1 M KHCO.sub.3 solution on Gold and on Gold-Nickel deposited membrane electrodes. The CO2 formation resultsfrom the bicarbonate oxidation, while O.sub.2 evolution results from the expetected OER process of water splitting.