BE1013897A3 - METHOD AND DEVICE FOR TREATING VAPORS EMITTED DURING THE PUMPING OF LIQUIDS CONTAINING VOLATILE COMPOUNDS DURING CLEANING OR FILLING OPERATIONS. - Google Patents

Abstract

Method and device for treating vapors emitted during the pumping of liquids containing volatile flammable and / or smelly and / or toxic compounds, during cleaning operations or during a filling operation, in particular using combined vacuum cleaners. Process characterized in that, before being discharged into the atmosphere, the flow to be treated is passed through the volatile compounds which are present there, are adsorbed on a support based on activated carbon fibers.

Description

"Method and device for treating vapors emitted during the pumping of liquids containing volatile compounds during cleaning or filling operations"

The present invention relates to a process for treating vapors emitted during the pumping of effluents, noble products or liquid industrial or household waste containing compounds, in particular volatile flammable and / or smelly and / or toxic organic compounds in a cleaning, in particular a combined vacuum cleaner or pumping equipment and transport of noble products.

Cleaning operations, requiring the pumping of noble products, effluents or liquid waste, must frequently be carried out as well within the framework of industry as in the communities or at private individuals (filling and transport of noble products , industrial cleaning, cleaning of sewers, pits, cleaning of sewage treatment plants, fuel tanks, service station tanks ...). These cleaning or transport operations are generally carried out by service providers using specific suitable vehicles known as “hydrocure vacuum cleaner combinations” or any other transport or similar rolling stock.

These cleaning installations are, as a general rule, equipped with an effluent or waste collection tank, on the one hand, cooperating with a pump, in particular a vacuum pump or a volumetric pump or one with gravity filling and, on the other hand, associated with a flexible pipe as well as a pipe for evacuating into the atmosphere the vapors emitted by the effluents or waste pumped; this evacuation pipe is preferably equipped with filtration members as well as a vent valve.

More specifically, the effluents or noble products or waste can in a first phase be transferred by pumping into the tank using a vacuum pump or possibly using a positive displacement or gravitational pump, but a vacuum pump is generally implemented at the end of pumping; this operation is also most often accompanied and / or followed by a final cleaning under pressure with water at the end of which the dirty cleaning water is also pumped under vacuum to be collected in the tank.

The effluents or waste pumped during these various operations very frequently contain compounds, in particular volatile organic compounds, which have the particularity of being combustible, that is to say of risking ignition or possibly explode when mixed with air, oxygen, or other oxidizing gas in suitable proportion, in the presence of an ignition source.

To quantify this risk, specialists have developed the habit of defining the concept of lower ignition limit or lower explosion limit of a gas or vapor in the air; this corresponds to the minimum concentration of this vapor above which the mixture can be ignited or can explode.

Specialists have also defined the concept of flash point of a vapor in the presence of the liquid which gives rise to it: this corresponds to the minimum temperature at which a mixture of this vapor and air can be ignited under normal conditions of pressure. It should be noted that the flash point is close to the temperature at which the saturated vapor pressure makes it possible to reach, in its mixture with air, the concentration corresponding to the lower explosive limit.

However, in cleaning and filling operations of the aforementioned type, the pumping of effluents, or noble products or waste results in the emission of vapors which are evacuated into the atmosphere, by the evacuation pipe. In the particular case of the implementation of a vacuum pump, such a pumping can be subdivided into two distinct stages, namely a first stage during which the liquid stream pumped in the flexible suction pipe is homogeneous and does not contain no air, and the vapor concentration at the pump's exhaust outlet is maximum, and a second stage during which the effluent or waste pumped no longer has a volume large enough to ensure a homogeneous liquid stream, and the pumped flow contains a gaseous phase formed mainly of more or less stale air; this second stage involves a greater degassing of the effluent or waste with an emission of vapors whose concentration can be more diluted.

During these two pumping stages, the lower ignition or explosive limit can be reached, which exposes to danger the personnel assigned to these operations as well as all persons likely to be near or in the sphere of influence of the gases thus emitted as well as the environment.

In addition, the vapors emitted during the aforementioned pumping or filling operations can also create odor nuisances since they very often contain smelly compounds (ammonia, hydrogen sulfide, mercaptans, acetic or butyric acid ...) whose presence may cause discomfort from a concentration of 3 on the order of 0.001 mg / Nm.

In addition, the vapors emitted during the above-mentioned pumping or filling operations can also be toxic to the organism and create medical nuisances since they very often contain carcinogenic and carcinogenic compounds. This notion of toxicity is expressed by the ELV (exposure limit value) thresholds which are set by official medical organizations.

It should also be noted that the authorities have established standards for emissions to the atmosphere, which in all probability will become more and more stringent in the future; it follows that vacuum pumping can be prohibited in the context of certain activities, in particular, industrial.

The object of the present invention is to remedy these drawbacks by proposing a method for treating the vapors emitted during the pumping of effluents, noble products or liquid industrial or domestic waste with a cleaning installation of the aforementioned type, such as to eliminate the odor nuisance as well as the risks of ignition and explosion so as to allow vacuum pumping operations to be carried out in the course of certain activities where they were, until now, prohibited, while respecting the legislation in force or to come concerning the emission of odors and volatile organic compounds in the atmosphere.

To this end, the invention relates to a process of the aforementioned type, characterized in that, before its discharge into the atmosphere, the gas stream to be treated is passed through at least one purification device at the level of which the volatile, mainly flammable, toxic and / or smelly compounds, which are present there, are adsorbed on a support based on activated carbon fibers.

In the case of a cleaning installation comprising a tank associated with an evacuation pipe equipped with a vacuum pump, the purification device can advantageously be mounted on the evacuation pipe, upstream of this pump to avoid to be saturated by a mist of oil or water which may be formed by it. A purification device can however be placed downstream of the vacuum pump, and it is also possible to install two purification devices on the evacuation pipe, one upstream, the other downstream of the vacuum pump.

In the case of a cleaning installation equipped with a tank cooperating, on the one hand, with a flexible pipe on which is mounted a positive displacement pump and associated, on the other hand, with an evacuation pipe provided with a air vent valve, the purification device must be mounted on the evacuation pipe, upstream of this valve.

In the case of a cleaning installation equipped with a tank cooperating, on the one hand, with a flexible pipe in gravity filling and, on the other hand, with an evacuation pipe provided with a shut-off valve. 'air, the purification device is necessarily mounted on the evacuation pipe, upstream of this valve.

The present invention also relates to a purification device allowing the implementation of the above-mentioned method.

According to the invention, this device consists of a tank closed by a cover, comprising an inlet orifice and an outlet orifice for the gas flow to be treated, and provided at its internal part with at least one removable cartridge equipped with an adsorbent support based on activated carbon fibers and designed so that it can be incinerated after use without generating waste.

According to a preferred characteristic of the invention, the adsorbent support consists of at least one layer of an activated carbon fabric or of another adsorbent material having similar adsorption kinetics - in particular by activated carbon powder - which is kept pleated with at least one layer of a support fabric, in particular based on a thermoplastic material (polypropylene, polyamide, polyester, polyethylene ...) or another material or mixture of materials capable of be incinerated without leaving any waste.

This support fabric can be either in the form of compacted fibers, or in the form of a mesh, or in the form of a fabric.

According to another particularly advantageous characteristic of the invention, the adsorbent cartridge is constituted by a tubular element closed by a flange at its respective ends and comprising an internal tube and / or an external tube essentially coaxial made of a synthetic mesh material and between which the adsorbent support based on activated carbon fibers is inserted.

The internal tube and the external tube make it possible to maintain the rigidity of the adsorbent cartridge and to facilitate its handling; they can be made of extruded polypropylene or other materials whose destruction by incineration does not generate waste (polyethylene, polyamide ...).

The flanges are preferably made of a polyolefin-based hot-melt resin or of other materials, the destruction of which by incineration does not generate waste such as ash, bottom ash, toxic gases, for example by epoxy resin. , polyester, hot melt polyamide ...

It should be noted that such an absorbent cartridge can be traversed by the gas flow to be treated, either from the outside to the inside or from the inside to the outside.

An adsorbent cartridge thus designed has the advantage of being very light, easy to handle, incinerable without waste and of having a very high autonomy and very high efficiency. Experience has shown that such a cartridge is capable of suppressing odors and of absorbing almost all of the volatile organic compounds which are usually encountered in the course of cleaning or filling operations of the aforementioned type.

Of course, depending on the type of operation implemented and its importance, the tank can be equipped with one or more adsorbent cartridges arranged in series or in parallel.

According to another characteristic of the invention, the purification tank is subdivided, by a partition, into two compartments, one of which, or the first compartment, comprises the inlet opening of the gas flow to be treated while the 'other, or second compartment, includes the outlet of this flow.

According to the invention, the partition is advantageously provided with at least one opening extending into the first compartment by a perforated distributor tube on which is threaded at least one adsorbent cartridge so that the gas flow to be treated must pass through the through this or these cartridges before entering the second compartment.

To enable such positioning of the adsorbent cartridges to be carried out, it is of course necessary that at least one of the flanges is provided with an opening at its central part.

A feature of the invention consists in treating the gas flow arriving in turbulent regime in the purification tank by radial adsorption through the cartridge in laminar regime then in output in tangential turbulent flow by means of the distributor tube.

According to another characteristic of the invention, the adsorbent cartridge (s) is (are) held in place by the cover of the tank, preferably by means of retaining springs.

The characteristics of the method and of the device which are the subject of the invention will be described in more detail with reference to the accompanying drawings in which: - Figure 1 is a schematic representation of a cleaning or filling installation equipped with 'a vacuum pump, - Figure 2 is a schematic representation of a cleaning or filling installation equipped with a positive displacement pump, - Figure 3 is a schematic representation of a cleaning or filling installation by gravity - Figure 4 is a sectional view of a purification tank, - Figure 4a is a top view of the partition wall, - Figure 5 is a perspective view of an adsorbent cartridge, - Figure 6 is a sectional view of an adsorbent cartridge threaded onto a distributor tube.

According to FIG. 1, the cleaning installation, which can in particular correspond to a combined vacuum cleaner, has the function of pumping effluents, noble products or liquid waste 1 contained in a tank 2 to transfer them to a tank 3.

To this end, the tank 3 is equipped, on the one hand, with a flexible pipe 4 capable of being immersed in the capacity 2 to allow the pumping of effluents, noble products or waste 1 which are contained therein according to the arrow a and, on the other hand, a pipe 5 allowing the evacuation into the atmosphere of the vapors emitted by these effluents, noble products or waste 1, during their pumping according to arrows b.

The evacuation pipe 5 is equipped with a vacuum pump 6 as well as filtration members 8 making it possible to subject the gas flow to be treated to a physical transformation.

According to the embodiment shown in FIG. 1, the evacuation pipe 5 is also equipped with two purification devices 9, 9 ′ which will be described in more detail in the remainder of this description and have the function of allowing the absorption on a support based on activated carbon of the flammable and / or smelly and / or toxic compounds present in the gas flow before the evacuation of this flow in the atmosphere. One of these purification devices 9 is mounted upstream of the vacuum pump 6 in the direction of circulation b of the gas flow to be treated, while the other purification device 9 'is mounted downstream of this pump .

Of course, the evacuation pipe could contain only one purification device 9 or 9 'without departing from the scope of the invention.

According to Figure 2, the effluents, noble products or waste 1, contained in the capacity 2, are pumped volu-metrically in the tank 3; for this purpose, a positive displacement pump 10 is mounted on the flexible pipe 4i plunging into the capacity 2 so as to pump the effluents, noble products or waste which are contained therein according to arrow a.

As in the configuration example shown in FIG. 1, the tank 3 is associated with an evacuation pipe into the atmosphere according to the arrows b of the vapors emitted by the effluents, noble products or waste 1 during their pumping. This discharge pipe 5 is equipped with a vent valve 7 as well as with a purification device 9 mounted upstream of the vent valve 7 in the direction of flow b of the flow. gaseous to be treated.

According to FIG. 3, the effluents, noble products or waste 1, contained in the capacity 2, are loaded gravely into the tank 3; for this purpose, the tank 3 is connected to the capacity 2 by a flexible pipe 4.2 allowing the transit of effluents, noble products or waste according to arrow a.

As in the configuration example shown in FIG. 2, the tank 3 is associated with an evacuation pipe into the atmosphere according to the arrows b of the vapors emitted by the effluents, noble products or waste 1 during their transit. This evacuation pipe 5 is equipped with a vent valve 7 as well as a purification device 9 mounted upstream of the vent valve 7 in the direction of circulation b of the gas flow to be treated.

According to the exemplary embodiments represented in FIGS. 1, 2 and 3, whatever the filling system or systems that may be associated, the purification device 9 and / or 9 ′ is always the same being given that the discharge pipe 5 is identical between the tank 3 and the purification device.

According to FIG. 4, the purification device 9 is constituted by a tank 11 closed by a cover 12 and comprising an inlet orifice 13 and an outlet orifice 14 for the gas flow to be treated; these orifices are extended by connection pipes 13 ', 14' allowing the tank 11 to be mounted on the discharge pipe 5 of the cleaning installation (Figures 1 and 3). The flow to be treated therefore circulates in the tank 11 according to the arrows b.

The purification tank 11 is further subdivided into two compartments 15, 16 by a partition 17 which, in the example configuration shown in FIG. 4a, has three openings 18.

The first compartment 15 has the inlet 13, while the second compartment 16 has the outlet 14.

As shown in Figure 4, the openings 18 of the partition 17 each extend into the first compartment 15 by a perforated distributor tube 19 on which is threaded an adsorbent cartridge 20 which will be described below in more detail and is maintained in place by the cover 12 by means of retaining springs not shown in the figures.

In view of this configuration, the gas flow to be treated coming from the first compartment 15 (arrow b) must be transferred to the internal part of the distributor tubes 19 through adsorber cartridges 20 before entering the second compartment 16.

Of course, the partition 17 could have a number of openings 18 other than three without departing from the scope of the invention; it should be noted that, in a manner not shown, one could also use a partition wall having only one opening extending by a distributor tube of great length on which several adsorbent cartridges can be threaded in series.

According to Figures 5 and 6, each of the adsorbent cartridges 20 is constituted by a tubular element designed so that it can be incinerated after use without generating waste. This element is closed at its respective ends by two flanges 21, 22, one of which 21 is full, while the other 22 has a central opening 23 allowing the cartridge 20 to be placed on a distributor tube 19, as shown in figure 6.

The tubular element 20 is delimited by two coaxial tubes made of a meshed synthetic material, namely an external tube 24 and an internal tube 25 between which is inserted an adsorbent support 26 based on activated carbon fibers which is not shown. in detail in Figure 6.

Claims (11)

CLAIMS 1 °) Process for treating vapors emitted during the pumping of effluents, noble products or industrial or domestic liquid waste containing volatile compounds which are mainly flammable, toxic and / or smelly in a cleaning installation or during a filling operation , in particular a combined vacuum cleaner, or pumping equipment and transport of noble products equipped with a collection tank (3) for effluents or waste (1), on the one hand, cooperating with a pump, in particular a pump vacuum (6) or a positive displacement pump (10), or alternatively with gravity filling and, on the other hand, associated with a flexible pipe (4, A \ r 42) with a pipe (5) for evacuation in the atmosphere of the vapors emitted by effluents, noble products or pumped waste which is preferably equipped with filtration members (8) as well as a vent valve (7), characterized in that before its evacuation d in the atmosphere, the gas stream to be treated is passed through at least one purification device (9, 9 ′) at which the volatile compounds which are present there are adsorbed on a support (26) based on activated carbon fibers. 2) method of treating vapors in a cleaning or filling installation equipped with a tank (3) associated with an evacuation pipe (5) equipped with a vacuum pump (6) according to claim 1, characterized in that the evacuation pipe (5) is provided with a purification device (9) mounted upstream of the vacuum pump (6). 3) Method of treating vapors in a cleaning or filling installation equipped with a tank (3) associated with an evacuation pipe (5) equipped with a vacuum pump (6) according to any one of Claims 1 and 2, characterized in that the evacuation pipe (5) is provided with a purification device (9 ') mounted downstream of the vacuum pump (6). 4 °) Process for treating vapors in a cleaning or filling installation equipped with a tank (3) cooperating with a flexible pipe (41) on which is mounted a positive displacement pump (10) and associated with an evacuation pipe (5) provided with a vent valve (7) according to claim 1, characterized in that the pipe (5) is provided with a purification device (9) mounted upstream of the valve in the open air (7). 5 °) Process for treating vapors in a cleaning or filling installation equipped with a tank (3) cooperating with a flexible pipe (42) allowing the gravitational transit of effluents, noble products or waste and associated with a pipeline discharge (5) provided with a vent valve (7) according to claim 1, characterized in that the pipe (5) is provided with a purification device (9) mounted upstream of the vent valve (7). 6 °) purification device for implementing the method according to any one of claims 1 to 4, characterized in that it is constituted by a tank (11) closed by a cover (12) having an orifice inlet (13) and an outlet orifice (14) of the gas flow to be treated and provided at its internal part with at least one removable cartridge (20) equipped with an adsorbent support (26) based on activated carbon fibers and designed so that it can be incinerated after use without generating waste. 7 °) Device according to claim 6, characterized in that the adsorbent support (26) consists of at least one layer of an activated carbon fabric or of another adsorbent material having similar adsorption kinetics - in in particular by activated carbon powder - which is kept pleated with at least one layer of a support fabric, in particular based on a thermoplastic material (polypropylene, polyamide, polyester, polyethylene ...) or a other material or mixture of materials capable of being incinerated without leaving waste. 8 °) Device according to any one of claims 6 and 7, characterized in that the adsorbent cartridge (20) is constituted by a tubular element closed by a flange (21, 22) at its respective ends and comprising an internal tube ( 25) and / or an outer tube (24) essentially coaxial, made of a mesh or perforated synthetic material and between which is inserted the absorbent support (26) based on activated carbon fibers. 9 °) Device according to any one of claims 6 to 8, characterized in that the purification tank (11) is equipped with one or more adsorbent cartridge (s) (20) arranged (s) in series or in parallel. 10 °) Device according to any one of claims 8 and 9, characterized in that the purification tank (11) is subdivided by a partition (17) into two compartments including one, or first compartment (15 ), comprises the inlet orifice (13) of the gas flow to be treated while the other, or second compartment (16), comprises the outlet orifice (14) of this flow, the partition wall (17) being provided with at least one opening (18) extending into the first compartment (15) by a perforated distributor tube (19) on which is threaded at least one adsorbent cartridge (20) so that the gas flow to be treated must necessarily pass through this or these cartridges (20) before entering the second compartment (16). 11 °) Device according to any one of claims 6 to 10, characterized in that the or the cartridge (s) adsorbent (s) (20) is (are) kept bare (s) in place by the cover (12) of the tank (11), preferably by means of retaining springs.