WO2016068778A1

WO2016068778A1 - Method for contacting a gas composition with a liquid composition

Info

Publication number: WO2016068778A1
Application number: PCT/SE2015/051121
Authority: WO
Inventors: Kari MUNUKKA
Original assignee: Climeon Ab
Priority date: 2014-10-29
Filing date: 2015-10-21
Publication date: 2016-05-06

Abstract

A method for contacting a gas composition with a liquid composition for the purpose of extracting components or condensing components partly or wholly. A device (1) is provided having a plurality of essentially parallel slots (6) through which liquid can be ejected from the device (1), the device is positioned in a vessel (10) into which a gas stream enters, liquid is pumped into the inside of the device and is ejected through the essentially parallel slots (6), thereby forming a plurality of stacked liquid discs, whereby the velocity of the liquid, the thickness of the liquid films and the spacing between the liquid discs are adjustable. As an alternative a device (1) is provided comprising a plurality of impaction pin spray nozzles (24) in a vessel (10) into which a stream of a gas composition is arranged to enter, the velocity or flow rate of the liquid composition and droplet size of said liquid composition being adjustable. The invention also concerns a use of the method and an apparatus.

Description

METHOD FOR CONTACTING A GAS COMPOSITION WITH A LIQUID COMPOSITION

Field of the Invention

This invention relates to the field of gas treatment,

enrichment of components in gas streams, physical and chemical extraction and condensation. The invention also relates to power generation in Rankine or Organic Rankine Cycles (ORC) or heat pumps, including more recent developments such as

described in WO 2012/128715, WO 2014/042580, SE 1300576-4 (not published), SE 1400160-6 (not published), SE 1400027-7 and 1400349-5 (not published), all of which are included by reference .

Background of the Invention and prior art

Gas treatment including washing, extraction of undesirable components, absorption, condensation of one or more

components, both in flow-through and dead-end configuration, is a standard unit operation in the oil, gas and chemical industry, see e.g. "Grundoperationen chemischer

Verfahrenstechnik", 8.ed., Vauck/Miiller , ISBN3-527-28031-6 , or Perry's Chemical Engineer's Handbook, ISBN 0-07-049479-7, section 18.41. Among the many techniques available for such gas treatment is the wide-spread counter-flow contacting falling liquid droplets with a gas stream flowing upwards. Falling droplets may form in a spray created in special nozzles where e.g. a liquid jet impinges on a small pin thereby creating a cone which subsequently breaks up into droplets of e.g. 10-500 micrometer size, alternatively the liquid is passed over a packed bed such as a multitude of e.g. Raschig rings. Relevant disclosures in the field are US 2010/0236 242, Kasra Farsad et al, "Systems and methods for processing of C02", US 4,991,780, R. Kannan et al, "Duocone spray nozzle", Krzysztof Karkoszka, Licentiate Thesis 2005, KTH Stockholm,

"Theoretical investigation of water vapour condensation in presence of noncondensable gases", US 7,654,509, S. Freitas et al, "Desuperheater spray nozzle", US 8,579,213, S. Myers et al, "Single circuit multiple spray cone pressure atomizers", Minoru Takahashi, "Study on vapor condensation heat transfer to liquid spray", 7^th international conference on nuclear engineering, Tokyo, Japan, April 19-23, 1999 ( ICONE-7481 ) , US 2005/0056 711, Th . Mee, "Multiple spray apparatus", and industrial disclosures, e.g. web site descriptions on e.g. jet spray deaerators. A further relevant publication is GB 1357

783 by Carrier Drysys Limited which teaches gas treatment in a flow-through apparatus by jetting a liquid through peripheral openings. The liquid forms circular or arcuate curtains directed towards the side of the casing, and the gas to be treated is flowing through said curtains. Gas absorption or phase change to liquid is not mentioned.

The engineer who has the task of providing an efficient process is confronted with a number of challenges which are well highlighted a.o. in Farsad's and Mee's disclosures: a) fill the gas space with as many liquid (droplets or other dispersed forms) as possible, b) provide a large surface at low energy consumption, c) balance available surface with speed of absorption, extraction, washing etc., d) use

available volume efficiently, e) prevent losses, e.g. by small droplets condensing to larger droplets, or by liquid at high speed hitting a wall of the container, f) prevent adverse interference with the gas stream, g) manage temperature increases, e.g. caused by absorption or condensation

enthalpies, and h) provide cooling or warming of gas and/or liquid streams as the case may be. Some of these challenges are mutually exclusive, and technical solutions are often compromises, see e.g. both Farad and Mee suggesting multiple spray sections.

Brief description of the Invention In the following, the task at hand will focus on absorption or condensation of a gas composition stream in a dead-end

configuration, i.e. a gas composition stream is entering a vessel from e.g. a turbine or a compressor, and shall be absorbed or condensed completely to a liquid of liquid

composition in an absorption or condensation section. In this section, a pressure corresponding to or slightly above the vapour pressure of said liquid or liquid composition shall be maintained. The technique disclosed here is more universally applicable e.g. in gas treatment including carbon capture chemistry, however, the main embodiment disclosed here relates to power generation processes such as Rankine cycles, ORC, and Carbon Carrier Cycle (C3) as described in WO 2012/128715 and WO 2014/042580, SE 1300576-4 (not published), SE 1400027-7 and SE 1400 160-6 (not published), hereby incorporated by

reference.

The solution presented here comprises the generation of a large surface for absorbing gas by generation of a multitude of liquid disks generated in a simple and robust device. The term "liquid disks" is to be understood as follows: Liquid is forced at a certain speed through the openings/slots of the device, thereby forming a thin film moving away from the openings or slots of said device. The film may break up into droplets at a certain distance from the device. The device can be built in one embodiment from threaded bars, guiding rods, specially shaped disks and spacer rings, although other mechanical solutions are conceivable and shall be seen as falling under the spirit of the invention. Said device being placed in a vessel so as to form a suitable apparatus for contacting a gas composition with a liquid composition for the purpose of extracting components, or condensing components, partly or wholly or otherwise change the mass balance between said gas composition and said liquid composition. The disks are stacked in a way allowing liquid to escape from the device horizontally in the form of discs. Gas easily enters the space between the liquid discs. The liquid may be pumped into the device with a certain pressure such as 0.05 bar or 0.5 bar above the prevailing gas pressure in the absorber or condenser vessel. Following the collection of liquid after having passed through the device, the liquid may be recirculated for e.g. cooling or heating, after which it may pass through the device again. The liquid composition may be partly, 98% or less, recirculated to the vessel. In this way, energy-efficient absorption or gas treatment is achieved. Utilization of the volume of the absorption vessel is very high and close to the practical maximum. Note that a dead-end liquefaction of gas has been described above to illustrate the invention, but flow-through

arrangements are conceivable as well.

Thus, by the invention is achieved a method for contacting a gas composition with a liquid composition for the purpose of extracting components, or condensing components, partly or wholly, or otherwise change the mass balance between said gas composition and said liquid composition, comprising the steps of:

- a) providing a device having a plurality of essentially parallel spaced apart slots through which said liquid

composition can be ejected from the device,

- positioning the device in a vessel into which a stream of said gas composition is arranged to enter,

- pumping said liquid composition into the inside of the device and ejecting said liquid composition through said essentially parallel spaced apart slots, thereby forming a plurality of spaced apart stacked discs of said liquid

composition in the form of thin liquid films, or

- b) providing a device comprising a plurality of impaction pin spray nozzles through which said liquid composition can be ejected from the device, where the pin of each nozzle is ideally placed at the rear of the nearest nozzle,

- pumping said liquid composition into the inside of the device and ejecting said liquid composition through said nozzles, thereby forming a plurality of spray clouds

comprising said liquid composition in the form of liquid droplets ,

wherein in case a) velocity or flow rate of the liquid

composition, thickness of the liquid films and the spacing between the stacked discs of said liquid composition being adjustable or in case b) velocity or flow rate of the liquid composition and droplet size of said liquid composition being adjustable, and wherein a preferred gas pressure range, prevailing in the vessel when the gas composition is contacted with the liquid composition, is 10-800 mbar, more preferably 30-600 mbar, in the case the vessel is used in connection with power generating, and a preferred gas pressure range, prevailing in the vessel when the gas composition is contacted with the liquid composition, is 2-50 bar, more preferably 5-20 bar, in the case the vessel is used in connection with heat pumps .

By the invention is achieved also an apparatus for performing the method according to the invention, comprising a vessel having a liquid composition inlet, a liquid composition outlet and a gas inlet in which vessel is placed a) a device

comprising threaded bars, guiding rods, spacers and solid disks arranged so as to form said device having a plurality of slot through which a liquid composition can be ejected, said solid disks being shaped at their circumference such that the liquid composition is ejected through the slots in the shape of essentially parallel liquid discs, or segments of liquid discs, or b) a device comprising liquid composition supply pipe or pipes, nozzles and one or more cover (s) for protection of the nozzles from unwanted spray and splashing, the liquid composition being arranged to be supplied to each nozzle by said liquid composition supply pipe or pipes.

Brief Description of the Drawings

The invention is described in more detail below in the form of a non-limiting example, reference being made to the

accompanying drawings, in which

- Figure 1 is a schematic drawing of a first embodiment of a absorption device which allows the generation of liquid discs formed by a liquid composition and escaping the device

horizontally,

- Figure 2 is a schematic drawing of the absorption device showing threaded bars, spacers, guiding rods and specially shaped rings, and, - Figure 3 is a schematic drawing or close-up showing that the solid disks have a certain profile at the edge, defining the liquid flow through openings/slots,

- Figure 4 is a schematic perspective drawing of a second embodiment of a absorption device which allows the generation of a plurality of spray clouds in the form of liquid droplets of a liquid composition,

- Figure 5 shows a sectional side view of a portion of the absorption device shown in figure 4, and

- Figure 6 shows the absorption device built into a vessel.

The figures are further explained under "embodiments". The figures merely intend to illustrate the invention. A range of standard engineering methods are available to realize modified embodiments which may be more suitable for mass production, however, the main purpose of the invention is to enable the efficient absorption or condensation of gas by providing a large surface of a liquid in an economical manner. Detailed Description of Preferred Embodiments

The terms "gas composition" and "liquid composition" should be understood to include both a one component gas or liquid as well as mixtures of two or more gases and liquids as well as liquids comprising other elements necessary for performing the claimed method.

This invention concerns in one aspect a method or procedure for the treatment of a gas composition with a liquid

composition, by which method the gas composition is contacted with the liquid composition for the purpose of extracting components, or condensing components, partly or wholly, or otherwise change the mass balance between said gas composition and said liquid composition. The liquid composition can be the same as the incoming gas, e.g. water or organic solvent such as acetone or isopropanol or ethanol or methanol or

refrigerants such as R134a and similar, or it may be

different, such as amine in water or solvent absorbing

incoming C02 from a gas stream such as flue gas or raw biogas. The essential difference to conventional liquid-gas contacting devices is that, in one embodiment, a plurality of essentially parallel discs of liquid composition is ejected from the device according to the invention such that the available volume of the vessel (possibly in the form of an absorber or condenser) is used effectively. Further, gas composition entry between the liquid discs is essentially unhindered. In one embodiment, the working fluid/liquid composition may comprise a low boiling solvent such as water, methanol, ethanol, acetone, isopropanol or butanol or coolants or refrigerants such as R134a, R245fa or similar, alone or in any mixing ratio. In different embodiments, the working fluid or liquid composition may be amines or ammonia in solution or nano- or micro-particles in water or solvent, capable of absorbing C02 from a gas stream.

Figure 1 shows a first embodiment of a device 1, which may be used for absorption, comprising a plurality of spacers 2, solid discs 3, guiding rods 4, threaded bars 5, and having opening/slots 6 between the solid discs 3. The spacers 2 are placed between the solid discs 3 so as to enable the formation of the slots 6 from which a plurality of essentially parallel discs of liquid composition is ejected. The gas composition entering between the liquid discs is essentially unhindered. It should be understood that various embodiments are

conceivable, including shaped disks 3, slots 6 of varying gap width and profiles, segmented openings 6, and many different mechanical solutions. The liquid composition is in this embodiment pumped into the device 1 from the top so as to form liquid composition discs. Depending on the shape of the solid discs 3 and slots 6, the flow of the liquid composition may be non-horizontal (with reference to figure 1) and/or regular or irregular. The plurality of discs forms circular

openings/slots 6. The openings are defined by the height of the spacer 2. The threaded bars stabilize the construction, and the guiding rods align the solid discs. An outward flow of the liquid composition is preferably but not necessarily perpendicular to a vertical direction (with reference to figure 1) (or the guiding rods 4 and threaded bars 5) . The profile of solid disks 3 may be adjusted to the viscosity or other parameters given by the liquid composition used. The profile can be realized by any mechanical shaping or additive methods or thin (e.g.) metal discs welded or glued onto solid discs 3.

In one embodiment, as shown in figure 6, the device 1 is positioned in a vessel 10 such that a gas composition is entering the space between the liquid discs in horizontal direction (with reference to figure 6) . In order to prevent liquid ingress upstream, i.e. into the turbine, the slots 6 facing the turbine (not shown) are closed such that the discs are not completely escaping at 360°, but at e.g. 300° (not shown) . Practically, this can be achieved by placing solid segments (not shown) such as 60° disc segments blocking the slots 6. In a different embodiment, gas enters from above or from the sides. Said solid segments, e.g. covering 20, 30, 60° or more can be arranged in a spiral-like manner such that the gas entering is forced to follow said spiral.

In figure 6 the absorption device is placed into a vessel 10 comprising a liquid inlet 11, a liquid outlet 12 and a gas inlet 13. Various devices may be built into such a vessel.

Typical operation parameters and dimensions are given in the following for the useful case where 2 kg/sec acetone vapour is condensed at about 0.25-0.45 bar (25-45 kPa) static pressure at about 20-35 °C.

Device diameter 200 mm. A width or gap of the slots 6 is 0.05- 5 mm, preferably 0.2-2 mm. A liquid pressure provided by an external pump (not shown) is at least 0.05 bar, likely in a range of 0.05-5 bar, more likely in the range of 0.1-2 bar. Liquid acetone flows through the device at a rate of 70 liter/sec. The device may have any shape but for manufacturing reasons it is practical to use a round or rectangular device. Preferred materials used: stainless steel for the threaded bars 5, metal or polymer for the solid discs 3, metal or polymer for the spacers 2.

Hardware parameters such as the pumping pressure and the dimensions of the device and the slots, as well as physico- chemical properties such as solvent viscosity, surface tension etc. determining the efficiency of the gas treatment. In the case of the absorption of gaseous acetone, surface tension and viscosity of liquid acetone are very low such that complete absorption or condensation of gaseous acetone using the device according to the invention is easy and efficient. In one embodiment, all liquid composition ejected through slots 5 will either collect on the vessel walls and/or will flow by gravity towards the bottom 14 of the vessel 10 from which it will be pumped for further processing, such as cooling, heating, or evaporation.

A second embodiment of a device 20 is shown in figures 4 and 5, in which the liquid composition is supplied by a liquid composition supply pipe or pipes 21. The liquid composition supply pipe or pipes 21 can be centric or peripheral or arranged in any other way. The liquid composition is supplied to each nozzle 24 by one or more supply pipe(s) 25. Each nozzle 24 is protected from unwanted spray and splashing of the other nozzles by one or more cover (s) 22. In this

embodiment the nozzle 24 and spray cover (s) is (are) supported and aligned by attachment spokes 23. Each nozzle 24 is jetting or impacting on the impaction pin of the nozzle below.

Preferably a stack of vertically spaced downward spraying impaction pin spray nozzles is used in the device 20 where the pin of each nozzle 24 is located at the rear of the nozzle below, as shown in figure 5. For clarity, the term vertical or vertically is used to explain the configuration of the device in figures 4 and 5, but in practice the device may be placed in any suitable orientation within the vessel 10.

Each such stack can have other similar stacks next to it and the supply pipes 25 can be shared between the stacks. The supply pipe or pipe(s) can be positioned in any manner for example in the center or in the periphery of a circular spray nozzle stack arrangement. In one embodiment, the technique is used as an absorber or a condenser in electricity generating machines, such as Organic Rankine Cycles. In this case, the preferred pressure range prevailing in the absorption section is 10-800 mbar, more preferably 30-600 mbar. In another embodiment, the technique is used as absorber or condenser in heat pumps. In this case, the preferred pressure range prevailing in the absorption section is 2-50 bar, more preferably 5-20 bar. In further embodiments, the technique is used to remove non-condensable gases from e.g. Organic Rankine cycles or heat pumps.

In one embodiment, essentially all gas composition entering the vessel 10 is absorbed or condensed. In other embodiments, a part of the gas composition stream entering the vessel is also leaving the vessel. Typically, the chemical composition of the gas composition stream entering the vessel will be different from the composition of the gas composition stream leaving said vessel, e.g. C02 may have been extracted from raw biogas or flue gas or mixtures of hydrogen, C02, CO and H20, whereas in these cases hydrogen, methane, nitrogen and oxygen are not absorbed or condensed.

In one embodiment, the liquid composition pumped through the device may contain particles preferably smaller than 0.5 millimetres, such as zeolites comprising C02-absorbing chemical functionalities, such as chemically bonded amines.

Similar arrangements or combinations of embodiments should be seen as falling under the spirit of this invention.

In summary, a simple solution is disclosed for the treatment of gas composition ( s ) , both in closed-loop-processes and partial flow-through processes, especially with limited availability of space. The solution is energy-efficient and cheap in construction and operation.

Claims

Claims :

1. A method for contacting a gas composition with a liquid composition for the purpose of extracting components, or condensing components, partly or wholly, or otherwise change the mass balance between said gas composition and said liquid composition, comprising the steps of:

- a) providing a device (1) having a plurality of essentially parallel spaced apart slots (6) through which said liquid composition can be ejected from the device (1),

- positioning the device (1) in a vessel (10) into which a stream of said gas composition is arranged to enter,

- pumping said liquid composition into the inside of the device (1) and ejecting said liquid composition through said essentially parallel spaced apart slots (6), thereby forming a plurality of spaced apart stacked discs of said liquid

composition in the form of thin liquid films, or

- b) providing a device (20) comprising a plurality of

impaction pin spray nozzles (24) through which said liquid composition can be ejected from the device (20), where the pin of each nozzle is ideally placed at the rear of the nearest nozzle,

- positioning the device (20) in a vessel (10) into which a stream of said gas composition is arranged to enter,

- pumping said liquid composition into the inside of the device (20) and ejecting said liquid composition through said nozzles (24), thereby forming a plurality of spray clouds comprising said liquid composition in the form of liquid droplets ,

wherein in case a) velocity or flow rate of the liquid

composition, thickness of the liquid films and the spacing between the stacked discs of said liquid composition being adjustable or in case b) velocity or flow rate of the liquid composition and droplet size of said liquid composition being adjustable, and wherein a preferred gas pressure range, prevailing in the vessel when the gas composition is contacted with the liquid composition, is 10-800 mbar, more preferably 30-600 mbar, in the case the vessel is used in connection with power generating, and a preferred gas pressure range,

prevailing in the vessel when the gas composition is contacted with the liquid composition, is 2-50 bar, more preferably 5-20 bar, in the case the vessel is used in connection with heat pumps .

2. The method according to claim 1, further comprising the steps of :

- feeding the gas composition to the vessel (10) so that the gas composition enters said vessel from any side including top and bottom, and

- placing the device (1; 20) in the vessel (10) so that the gas composition stream is not deflecting the essentially parallel spaced apart liquid discs in case a) , or the spray droplets in case b) , in their movement, e.g. by segmenting the flow of the liquid composition.

3. The method according to claim 1 or 2, further comprising the steps of :

- collecting said liquid composition pumped through the device (1; 20) after having passed through the slots (6) in case a) or spray nozzles (24) in case b) and after having absorbed or condensed said gas composition entering the vessel (10),

- treating said liquid composition after the collection by heat-exchanging against a cold or hot source and/or by

extraction, and

- partly, 98% or less, recirculating said liquid composition to the vessel (10) .

4. The method according to anyone of the preceding claims, for ideally complete absorption or condensation of a working fluid in a Rankine cycle, including Organic Rankine Cycles, Kalina cycle, Carbon Carrier cycle and other thermodynamic cycles for energy production, and heat pumps, i.e. said working fluid is selected from the group consisting of water, alcohols such as methanol and ethanol and isopropanol, ketones such as acetone and MEK, amines or ammonia, amines or ammonia in combination with C02, refrigerants such as R134a, 245fa, Solvokane, as well as mixtures of solvents and mixtures with nano-sized or micron-sized solid absorbents.

5. The use of the method according to anyone of the preceding claims, for treatment of industrial gases, including synthesis gas treatment, C02 absorption by amine treatment, natural and biogas gas treatment and sweetening.

6. An apparatus for performing the method according to any one of claims 1 to 4, comprising a vessel (10) having a liquid composition inlet (11), a liquid composition outlet (12) and a gas inlet (13) in which vessel is placed a) a device (1) comprising threaded bars (5), guiding rods (4), spacers (2) and solid disks (3) arranged so as to form said device having a plurality of slots (6) through which a liquid composition can be ejected, said solid disks (3) being shaped at their circumference such that the liquid composition is ejected through the slots (6) in the shape of essentially parallel liquid discs, or segments of liquid discs, or b) a device (20) comprising liquid composition supply pipe or pipes (21), nozzles (24) and one or more cover(s) (22) for protection of the nozzles (24) from unwanted spray and splashing, the liquid composition being arranged to be supplied to each nozzle (24) by said liquid composition supply pipe or pipes (25) .

7. The apparatus according to claim 6, whereby shaping of the solid discs (3) are adapted to be realized by mechanical processing or by using washers of suitable diameters, and whereby the apparatus is preferably round, but optionally rectangular, hexagonal or of any other shape.

8. The apparatus according to claim 6 or 7, used for

deaeration or removal of non-condensable gases.