FR3044236A1 - DECANTATION COLUMN DEVICE - Google Patents

Abstract

The invention relates to a device (1) for fluid purification, comprising at least one flow channel (5) extending longitudinally between at least one inlet (3) of fluid to be purified (30) and at least one outlet (4) of purified fluid, characterized in that the surface of the cross-section of said flow channel (5) increases between the fluid inlet (3) to be purified and the purified fluid outlet (4) and that it further comprises at least one outlet (8) of the undesirable elements (7) comprising at least one sampling means (81, 82, 83) arranged transversely inside said flow channel (5).

Description

Field of the invention

The present invention is in the field of energy production by combustion or gasification of organic material. The invention particularly relates to a device for purifying gases or fumes but also the method of cleaning gas or fumes using said device.

State of the art

During a combustion of organic material in a boiler, for example for a production of heating energy or for a production of water vapor in an energy cogeneration process, fumes are emitted at the end of the transformation. of the raw material. These fumes are not removed as is in the environment for economic reasons, health and environmental protection.

Among the treatments that are applied to these fumes, filtration is an essential step in order to capture and eliminate the particles suspended in the fumes.

Another possible treatment involves the use of scrubbing cyclones which centrifuge the fumes in order to extract the heavier particles from the gas stream than the gases, by the play of the centrifugal force applied.

Another possible treatment concerns the washing of the fumes by showering with water possibly supplemented with collecting agents, in order to reduce the suspended matter which would otherwise be released into the atmosphere. The water flows down the reactor and is evacuated for purification treatment.

For the removal of undesirable chemical compounds, such as for example Nitrogen Oxides (commonly known as NOx), an addition of liquid or solid chemical reagent makes it possible to capture undesirable molecules; it is then a question of separating the additives from the flow of fumes discharged into the atmosphere.

During a synthesis gas production process, called syngas, by gasification of organic raw material, many undesirable elements are suspended in the gases produced. Their capture and elimination also depend on the tools listed above, namely filtration, cycloning, washing, capture by solid or liquid additives, etc.

The traditional solutions listed above have the particular defect of not being easily exploitable beyond 300 ° C, both for economic and technical reasons.

Sleeves in baghouses, usually polytetrafluoroethylene (PTFE), may melt or catch fire; washes are unthinkable because the water would be vaporized. Electrostatic precipitators are not designed for temperatures above 300 ° C and ceramic cartridge filters prove to be all the more expensive as hot gases have a low density, which has an upward impact on the flow rates to be treated and therefore the size of equipment. Only cyclones operate at high temperatures with acceptable yields, but they induce a large consumption of energy to ensure a high rate of injection of the gas to be treated in the cyclone.

Moreover, these solutions do not make it possible to sort the undesirable elements by categories, since they are eliminated in a single flow containing, for example, very large particles and the finest. Process releases may contain both sand particles larger than 1 mm and very fine ash dusts less than 10 microns in size. It is then most often mandatory to evacuate all the ashes in a specialized industrial waste treatment plant, while sand alone could be upgraded at a lower cost, especially since it often represents the largest mass released.

Description of the invention

The present invention aims to overcome the drawbacks of the state of the art by providing a device and a process for purifying gas flows and fumes from combustion operations and / or gasification of organic raw material.

Thus, the present invention particularly relates to a fluid purification device comprising at least one flow channel extending longitudinally between at least one fluid inlet to be purified and at least one purified fluid outlet, which is remarkable in that the surface of the cross-section of said channel increases between the fluid inlet to be purified and the purified fluid outlet and in that it further comprises at least one outlet of the undesirable elements comprising at least one sampling means arranged transversely to the interior of said flow channel.

According to a preferred embodiment of the invention, said sampling means comprises a hollow pipe comprising at least one perforation connecting the inside and the outside of said pipe.

According to a preferred embodiment of the invention, said purified fluid outlet is disposed at an altitude greater than said fluid inlet to be purified.

According to another preferred embodiment of the invention, said fluid inlet to be purified is disposed at an altitude greater than said purified fluid outlet.

According to an even more preferred embodiment of the invention, said purified fluid outlet is disposed at a distance of between 0.5 m and 6 m from said fluid inlet to be purified.

According to a preferred embodiment of the invention, said flow channel is included in an enclosure.

According to a preferred embodiment of the invention, said device further comprises means capable of generating a magnetic field and / or an electric field inside said flow channel.

According to a preferred embodiment of the invention, said device comprises several sampling means, included in the output of undesirable elements, divided into several stages.

According to an even more preferred embodiment of the invention, each of the stages comprises a plurality of hollow pipes arranged in parallel so as to form a sheet.

According to a preferred embodiment of the invention, said device further comprises a bypass, implanted downstream of the purified fluid outlet, comprising two connections downstream of the device, one called the final fluid outlet, and another called the purge exit.

According to an even more preferred embodiment, said purified fluid outlet and said purge outlet are mutually exclusive.

According to a preferred embodiment of the invention, said device further comprises at least one spraying means arranged to spray in the flow channel.

According to a preferred embodiment of the invention, said device further comprises a condensation means arranged inside the flow channel.

The present invention also relates to a method for purifying a fluid, characterized in that it comprises a step of circulating said fluid in a flow channel of a purification device between a fluid inlet to purifying and a purified fluid outlet, and in that the flow channel guides the fluid to be purified and undesirable elements from the inlet to the outlet in the space between its walls and in that the total area of the cross section of the channel increases between the inlet and the outlet, so that the flow velocity of the fluid to be purified decreases during its progression in the purification device and in that a braking force of the undesirable elements is applied in the channels, so that at least a portion of the undesirable elements can no longer be driven by the decreasing force of the fluid entrainment and stops in the flow channel in a zone of immob ilisation.

According to a preferred embodiment of the invention, said method further comprises a step of removing from said channel undesirable elements present in said immobilization zone.

According to a preferred embodiment of the invention, said method further comprises a step of condensing all or part of the fluid flowing in said flow channel.

According to a preferred embodiment of the invention, the braking force is due to terrestrial gravitation.

According to a preferred embodiment of the invention, the braking force is created by the buoyancy phenomenon Archimedes.

According to a preferred embodiment of the invention, said fluid is a liquid and the undesirable elements are solid particles.

According to another preferred embodiment of the invention, said fluid is a gas and the undesirable elements are liquid particles.

According to another preferred embodiment of the invention, said fluid is a gas and the undesirable elements are solid particles.

According to a preferred embodiment of the invention, the braking force is created by an electric and / or magnetic field applied in the flow channel.

According to a preferred embodiment of the invention, said method implements a device according to the invention.

Advantages of the invention The advantage of the invention is that the fluids of the process can be usefully purified whatever their temperature or their load of undesirable elements.

Another advantage is that it is possible to separately eliminate different categories of undesirable elements, which makes possible a specific valuation of the different categories of rejection. Other advantages and characteristics of the invention are described below according to possible solutions for carrying out the invention.

The descriptions refer to the following figures in the appendix: FIG. 1 schematically represents an embodiment of the device according to the invention equipped with 3 outputs of undesirable elements, according to 3 stages. FIG. 2 represents a variant of the invention in which several fluid flow channels are indicated. FIG. 3 represents another variant of the invention in which the samples of undesirable elements are distributed on the same stage. FIG. 4 represents another variant of the invention in which a spraying means is installed. FIG. 5 represents another variant of the invention in which a vapor condensation means is installed.

Presentation of an embodiment

The present invention relates to a device for purifying fluid, whether in liquid or gaseous form, based on the principle of immobilization of undesirable elements in a flow of fluid. The immobilized particles accumulate in an area of the device enclosure until an evacuation operation is performed.

In general, in the following description, the longitudinal and transversal terms will be used with the following meaning: a fluid which flows from a point A to a point B while being guided in a channel follows a so-called longitudinal flow, even if this flow is not rectilinear but curved or zigzagged. Equipment placed in this channel at a certain distance from the points A and B and which occupies a portion of the channel at this position and which is intended to act on this section perpendicular to the line AB will be defined as acting transversely. If the equipment is not perfectly perpendicular to the AB line, it will still be defined as transversal because it acts punctually on a channel section.

According to a preferred embodiment of the invention, the fluid is a gas and the undesirable elements are denser particles than the gas, the latter are solid or liquid and are mixed in suspension in this gas.

According to the embodiment shown in FIG. 1, the purification device 1 uses an enclosure 2, preferably sealed, which is supplied with fluid 30, which is preferably qaz, which it is desired to purify, from an inlet 3 to an outlet 4. Between these two connections, the fluid 30 preferably flows upwardly in a flow channel at a speed determined by the cross-sectional area of said channel 5 and the flow rate of the fluid 30. The chamber 2 and the channel 5 can be fused into a single element if all the fluid 30 flows in a single channel 5.

The surface of the cross section of the channel 5 is increasing between the inlet 3 and the outlet 4 of the enclosure 2 for the same flow of fluid. Thus, as it grows in channel 5, the speed of the fluid 30 is increasingly low.

In addition, the contamination contained in the fluid 30 is entrained in the chamber 2 by the latter. The undesirable elements targeted by the purification operation are then subjected to two forces of opposite direction: an upward driving force 101 maintained by the speed of the gas flow 30 and a braking force 102 downwards by the effect of gravitation.

At the bottom of the chamber 2, the gas velocity 30 is the highest and is such that all undesirable elements introduced into the chamber 2 are driven by the flow.

A drain means 50 serves to purge the bottom of the channel 5 or the chamber 2 if undesirable elements are so dense that they fall down the chamber 2, even in the zone of the entry 3 where the speed fluid 30 is maximum.

During the rise of the fluid 30 in the chamber 2, its speed decreases and some rather dense particles, for example, the particles 7 or 71, immobilize in the immobilization zone 9 or 91 because the two forces of opposite direction , driving force and braking force, then have the same intensity. The less dense particles do not stop and follow the higher gas flow. Then, as the speed decreases again, there is a new immobilization zone 92 in the enclosure where the driving force decreases enough to immobilize also less dense undesirable elements 72, and so on, for example in zone 93 with In exit 4, the purified gases are evacuated even if they may still contain some undesirable elements which would not have a sufficient density to be immobilized in the chamber 2.

For the sake of clarity, three distinct zones are described, but depending on the initial population of undesirable elements and the distribution of channel expansions inducing slowing down of the fluid 30, the immobilization zones can be much more numerous, even even not distinct if a continuous cloud of particles is immobilized in the fluid stream 30.

The immobilized particles accumulate over time and it is necessary to evacuate them regularly or continuously by means of sampling means, in order to prevent these immobilized undesirable elements from having time to disintegrate and return to the flow. or to cause clogging of the device 1. For this purpose, the invention proposes to place one or more sampling means 81, 82 or 83 in the immediate vicinity of the immobilization zones 91, 92 or 93. These means may be tubes hollow provided with perforations 86 to collect the fluid in these areas enriched in undesirable elements and to separately evacuate from the enclosure through a specific outlet 8 and sealed.

According to a preferred solution, the sampling means are hollow cylindrical tubes with an outside diameter of 60 mm and an internal diameter of 50 mm. These tubes are implanted transversely in the chamber 2 so as to pass through the entire area in which the fluid 30 to be purified.

Perforations with a diameter of about 20 mm are arranged along these tubes in order to enable them to take fluid present in the chamber 2.

In addition, these tubes are regularly arranged in the form of a sheet to allow a homogeneous sampling of an entire immobilization zone 9. For example, a complete sheet is composed of several sampling means arranged at the same altitude and each being distant from others from a distance of about 200 mm. These tubes of the same sheet are connected to a general collector, so that the fluid that exits through these tubes is grouped into a single flow of fluid.

According to a variant of the invention, these sampling means may take the form of one or more boxes installed transversely in the channel. Each box is sealed except at the perforations 86 which ensure the removal of undesirable elements immobilized and their outflow of the device 1.

In general, any form of hollow pipe for the removal and removal of unwanted elements is suitable.

The shape of the channel 5 is adapted by design to the flow rate of the fluid to ensure that the flow of the fluid 30 is stable, that is to say according to a regular velocity profile which ensures the absence of vortex or local recirculations which would degrade the effectiveness of the purification.

For example, if the fluid is a liquid, its flow rate will preferably be between 0.1 m / s and 10 m / s; and if it is a gas, its flow rate will preferably be between 0.5 m / s and 30 m / s.

According to an advantageous variant of the invention, the channel 5 has a vertical longitudinal axis and comprises 4 walls which are arranged so as to form a square section at the bottom and which gradually move away from each other at an angle of 30 ° in relation to the vertical. The upper section of channel 5 is still square but much wider.

In general, in the case of a continuous channel enlargement 5, the channel enlargement 5 must not be too pronounced and for this the angle 60 formed by the separation of the walls of the channels 5 is preferably less than 30. °.

In addition, in the case of a discontinuous channel enlargement, the increase in the cross-sectional area of the channel 5 is preferably less than 50%, more preferably less than 20% to limit the risk of introducing turbulence in the fluid flow.

According to a variant of the invention, it is possible to have several channels 5 fed in parallel by the same fluid inlet 30. This makes it possible to treat a large fluid flow rate 30 while maintaining a unitary channel section 5 optimized to impose a Flow velocity guaranteeing the absence of parasitic vortex in the fluid flow.

As indicated in FIG. 2, it is possible to combine the widening of the channels 5 and the addition of new channels 5 fed in parallel. The wall 61 creates two channels 51; the walls 62 create four channels 52 and the walls 63 create six channels 53. Thus, each channel 51, 52, 53 retains an optimized unit section but the total section of the enclosure is increased in two steps: from 51 to 52 and 52 to 53.

The sampling rate is subject to flow control in order to control the purification performance.

The sampling by the sampling means 81, 82, 83 of the immobilized undesirable elements can be carried out in a first continuous flow manner, which makes it possible to evacuate the unwanted elements as soon as they are immobilized in the flow without their do not stagnate; but this causes a large uncleaned fluid outlet.

A second way is to operate the sampling discontinuously, which has the advantage of limiting fluid loss 30, but creates the risk that between 2 sessions of sampling unwanted elements return into the flow and contaminate again the fluid 30.

These sampling means may be telescopic and be introduced regularly into the chamber 2 during sampling operations and be removed in the meantime so as not to disturb the flow of fluid 30 between two samples.

When these means are removed from the chamber 2, it is advantageous to carry out their possible cleaning. The invention applies as soon as it is possible to separate the fluid 30 and undesirable elements by the introduction of a force which opposes the entrainment of undesirable elements by the fluid 30.

For example, if the fluid is a liquid or a gas and the undesirable elements are solid or liquid elements of greater density than the fluid, then the channels 5 will be arranged substantially vertically with an organized flow of fluid from the bottom to the top to guarantee the opposition between the driving force by the fluid and the sedimentation force by density.

In a symmetrical way, if the undesirable elements are of smaller density than the fluid, in particular a liquid, then the flow will be organized from top to bottom, the buoyancy then opposing the flow downwards.

In all cases the flow of the fluid 30 will be organized substantially vertically, that is to say that the average velocity vector of the fluid stream 30 will preferably have a vertical component of at least 70% of its norm. The mean flow velocity vector is the vector which represents the mathematical average of each velocity vector of each fluid molecule 30.

The direction of flow, from bottom to top or from top to bottom, is simply determined by the difference in altitude between point of entry 3 and point of exit 4, provided that the flow then performs the most direct, at least without impromptu direction change.

Thus, in the case of a flow from bottom to top, it is advantageous to provide an altitude difference of 1 m, which represents a residence time in the device of 1 s if the flow is carried out at an average speed of 1 m / s. It is the same in the direction of the top down. The invention also applies to undesirable elements sensitive to the action of an electric or magnetic field. Thus, this field will be applied according to a variable intensity in different zones of the enclosure 2, in order to create separate immobilization zones. These areas are also equipped with sampling means.

In this case, the flow direction may not be vertical if the applied fields are adapted so that each undesirable element is subjected to a braking force 102 opposite to the driving force 101.

According to a variant of the invention, the evacuation of the undesirable elements immobilized in the chamber 2 can be performed discontinuously by a total purge. As indicated in FIG. 1, the output 4 is connected to a flux distribution means 40: in normal operation, said flow distribution means 40 communicates with the purified final fluid outlet 41; in purge operation, said means 40 communicates with a purge outlet 42 which then evacuates the entire flow to a discharge treatment means. At the same time, in purge operation, the fluid flow rate is temporarily increased by at least 20%, so as to make the driving forces by the fluid 30 greater than the braking forces prevailing in the chamber 2 and thus evacuate all the unwanted elements 7 previously immobilized towards the purge outlet 42.

In the case of braking force obtained by electric or magnetic field, the purge sought by the reduction or the suppression of braking force can be obtained by a change of the setting (reduction of the intensity of the field or complete stop) of the means of field generation, possibly in addition to an increase in the flow of fluid 30 to be purified.

According to a variant of the invention, as represented in FIG. 3, the sampling means can be separated into several action zones. Thus, the tube is divided into two parts 84 and 85 which take a different portion of the immobilization zone where it acts. Here, the portion 84 removes the left portion of the immobilization zone and the portion 85 removes the right portion of the immobilization zone. This makes it possible to control more precisely the homogeneity of the samples in the immobilization zone, in particular for large devices in which the flows are easily disturbed and non-homogeneous.

According to a variant of the invention, as indicated in FIG. 4, it is possible to combine a reagent injection means with the device. Thus, the shower injection 10 sprays a reagent into a part of the enclosure. This reagent captures the undesirable elements 7 and stagnates in the immobilization zone 9, so that a sampling means evacuates the unwanted elements captured by the reagent.

This reagent may be pure water, but also any other product for capturing undesirable elements, in liquid or solid form may be suitable. Similarly, the fluid to be purified may be a gas or a liquid.

For example, a spraying of activated carbon powder in a gasification syngas contaminated with chlorine vapors can advantageously make it possible to capture the chlorine present in the gas at first, and then to collect the powder used before the treated gas comes out of the device 1. Thus, a single device makes it possible to purify the syngas from its chlorine vapors, without emitting coal powder downstream.

Depending on the braking force that applies to this reagent, the immobilization zone after capture of the undesirable elements will be either below the point of injection of reagent, either in the same zone or above, since that the velocity of the fluid becomes low enough to immobilize the reagent and undesirable elements.

According to a variant of the invention, as indicated in FIG. 5, it is possible to use a means 11 for condensing water vapor or any other product, to be placed in the channel 5.

If the fluid to be purified is a gas, it may be advantageous to solicit the physical phenomenon of vapor condensation. For example, if the gas contains water vapor and has a sufficiently high temperature, this vapor is gaseous. If the gas is cooled below the dew point temperature of the water vapor, it becomes liquid and can no longer be contained as vapor in the gas. We then witness a phenomenon of condensation of water vapor. If these condensates are evacuated in liquid form and the gas is then warmed above the dew point, then its gaseous water vapor content will be lower than at the beginning of the operation. The gas has thus been "purified" totally or partially of its water vapor.

For example, if the gas is air at 20 ° C at atmospheric pressure and it contains 8 g of water per kg of air, then its cooling below 11 ° C makes it possible to reach the point dew and condense some of the water contained in the gas.

In the same way, a gasification gas contains vaporized elements which can be condensed by crossing the dew point temperature.

Thus, according to one variant of the invention, one or more condensation means 11, of the heat exchanger networks type, are installed in the enclosure 2, either on the periphery of the enclosure 2, or directly in the center of the flow channels for greater efficiency. They are fed with a cool heat transfer fluid which captures the heat of the fluid to be purified. This fluid is then voluntarily cooled below the desired dew point and the vapors it contains then condense. This generates drops of liquid that will be collected and discharged by means of sampling unwanted elements.

According to an improvement of the invention, these drops are also used to form a mist capable of capturing targeted undesirable elements when they come into contact and adhere to the droplets of the fog.

Then, the collection of these drops, pure or charged with undesirable elements collected, will be carried out below, above or at the altitude of the cooling point depending on the direction of the gas flow and the force of the applied braking.

According to another variant of the invention, a specific product is voluntarily introduced into the gas before its purification in order to make it play the role of collector vapor. This solution can obviously be combined with the reagent spray solution.

According to a variant of the invention, the walls of said device 1 are heated to promote the capture and evacuation of unwanted elements. The heating makes it possible to promote the fusion of targeted undesirable elements. The heating may be by electrical resistances, or by the passage of a thermal fluid in contact with the walls of the device.

According to another variant of the invention, the walls of said device 1 are cooled in order to promote the capture and evacuation of unwanted elements. The cooling makes it possible to favor the condensation of undesirable elements, which would come into contact with the walls of the device 1, and their subsequent evacuation.

According to one variant of the invention, in particular with the aim of minimizing the energy expenditure in the principle of cooling and / or heating the fluid 30, the enclosure 2 is insulated. The invention also relates to a purification method using the device, the means and the configurations described above.

Claims (14)

1-device (1) for cleaning fluid, comprising at least one flow channel (5) extending longitudinally between at least one inlet (3) of fluid to be purified (30) and at least one outlet (4) of purified fluid, characterized in that the surface of the cross-section of said flow channel (5) increases between the fluid inlet (3) to be purified and the purified fluid outlet (4) and in that it comprises at least one outlet (8) of the undesirable elements (7) comprising at least one sampling means (81, 82, 83) arranged transversely inside said flow channel (5). 2- Device according to claim 1, characterized in that said sampling means (81, 82, 83) comprises a hollow pipe comprising at least one perforation (86) connecting the inside and outside of said pipe. 3- Device according to one of claims 1 or 2, characterized in that said outlet (4) purified fluid is disposed at an altitude greater than said inlet (3) of fluid to be purified (30). 4- Device according to one of claims 1 or 2, characterized in that said inlet (3) of fluid to be purified is disposed at an altitude greater than said outlet (4) of purified fluid. 5- Device according to one of the preceding claims, characterized in that it comprises a means adapted to generate a magnetic field and / or an electric field within said channel (5) flow. 6. Device according to one of the preceding claims, characterized in that it comprises several sampling means (81, 82, 83) included in the output (8) of the undesirable elements, divided into several stages. 7- Device according to the preceding claim, characterized in that each of the stages comprises a plurality of hollow pipes arranged in parallel so as to form a sheet. 8- Device according to one of the preceding claims, characterized in that it comprises a bypass (40), located downstream of the outlet (4) of purified fluid, comprising two connections downstream of the device (1), one called the final fluid outlet (41), and the other called the purge outlet (42). 9- Device according to one of the preceding claims, characterized in that it comprises at least one spraying means (10) arranged to spray in the channel (5) of flow. 10- Device according to one of the preceding claims, characterized in that it comprises a condensing means (11) disposed within the channel (5) of flow. 11- A method for purifying a fluid, characterized in that it comprises a step of circulating said fluid in a flow channel (5) of a purification device (1) between an inlet (3). ) of fluid to be purified (30) and an outlet (4) of purified fluid, and in that the channel (5) guides the fluid to be purified (30) and the undesirable elements (7) from the inlet (3) to at the outlet (4) in the space between its walls (6) and in that the total area of the cross-section of the channel (5) increases between the inlet (3) and the outlet (4), whereby the flow velocity of the fluid to be purified decreases as it progresses in the purification device (1) and in that a braking force (102) of the undesirable elements (7) is applied in the channels (5). ), so that at least a part of the undesirable elements (7) can no longer be driven by the decreasing force (101) of the fluid (100) and stops in the the channel (5) in an immobilization zone (9). 12- Process for purifying a fluid according to the preceding claim, characterized in that it comprises a step of removing from said flow channel (5) the undesirable elements (7) present in said immobilization zone (9) . 13- Process for purifying a fluid according to one of claims 11 or 12, characterized in that it comprises a step of condensing all or part of the fluid flowing in said channel (5) flow. 14- Method according to one of claims 11 to 13 characterized in that it implements a device according to one of claims 1 to 10.