CZ170199A3 - Unit and method for removing mercury from waste materials by vacuum distillation process - Google Patents

Abstract

Mercury removal unit from waste materials vacuum distillation consists of at least three electrically edible, mobile, hermetically sealable ovens (1), which are connected through to form a bundle a connecting pipe (3) and a cooling unit (4) for distillation a container (5) connected to the vacuum pump (8). Riser (3) with a mercury trap (6) is incorporated into each coupling between the furnaces and the distillation vessel. Way removing mercury from waste materials by vacuum distillation It is that each of the series of mobile, hennetically sealed furnaces (1) are filled with mercury containing waste, the temperature in the furnaces is increased above 360 ° C and by means of a vacuum pump (8) creating a pressure of less than 101,3 kPa in the distillation vessel (5), water filter (9), piping (3,7 and 10), cooling unit (4) and the furnace (1) and the condensed mercury is collected in the collection sections (6). The furnace (1) is then disconnected from the distillation vessel (5) and they cool, their lids (2) are removed from them and the furnaces (1) are ready to accept the new refill.

Description

Unit and method for the removal of mercury from waste materials by vacuum distillation

Technical field

In particular, the present invention relates to a mercury removal unit by vacuum distillation comprising:

• a sealable chamber in which waste materials may be exposed to elevated temperature and reduced pressure; • a vapor duct from that chamber; and • a means to cool off the extracted vapors and collect condensed mercury.

BACKGROUND OF THE INVENTION

A unit of this type is described in SU 1 838 440 A3. The advantage of such a unit is that it is possible to reduce the amount of mercury vapors that could escape when removing mercury from herrings, batteries, fluorescent lamps, catalysts and the like, but it is not possible to achieve a situation where mercury vapor in the atmosphere can be reduced to a negligible percentage . There is still an environment containing mercury vapors hazardous to personnel near the unit.

It is an object of the present invention to overcome this drawback and to provide a unit with which the mercury removal process can be carried out in portions in hermetically sealed chambers without allowing the interfering air containing mercury strips to enter the atmosphere.

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SUMMARY OF THE INVENTION

According to the invention, the unit is characterized in that it comprises at least three electrically heatable mobile, hermetically sealable furnaces which are connected to form a group by means of a connecting pipe and a cooling unit for a distillation vessel, the vessel being connected to a vacuum pump.

In order to efficiently collect the mercury, a riser with a mercury trap is built into each connecting pipe between the furnaces and the distillation vessel.

The furnaces may be placed as a bundle around the distillation vessel and connected via their own connecting pipes to a common heat exchanger which is mounted on the distillation vessel and may be cooled with cooling water.

In order to prevent mercury condensation on the inside of the furnace lids, these lids may be dish-shaped or domed and extend into the furnace.

To further remove the substances, a water filter is built into the line between the distillation vessel and the vacuum pump, and an oil-water separator and one or more activated carbon filters for off-gas are then connected to the outlet side of the vacuum pump.

The invention also relates to a method according to which each of a series of mobile hermetically sealed furnaces filled with mercury waste is connected via a conduit with a condensed mercury collector section and a cooling unit for a distillation vessel, where the temperature of the furnaces is raised above 360 ° C by vacuum pump. a pressure of less than 100 mbar is generated in this distillation vessel, in these pipes, in the cooling unit and in the furnaces;

condensed mercury is collected in the collector portions and the furnaces are disconnected from the distillation vessel and cooled, their lids are removed therefrom and the furnaces are prepared to receive additional charge.

In order to remove the mercury according to the invention from complete batteries that have not been ground, it will be necessary to increase the vacuum to below 10 mbar.

The method of the invention can be carried out efficiently and rapidly and results in a substantially mercury-free ambient air. The dose-by-dose procedure, such that no interfering air enters the environment, is important. The time cycle is completely under control.

Overview of the drawings

Figure 1 shows a side view of a mercury removal unit according to the invention.

Figure 2 shows a view of the furnace used in this unit.

Figure 3 shows a plan view of the whole unit.

DETAILED DESCRIPTION OF THE INVENTION

The unit shown in Figure 1 comprises a plurality of mobile furnaces 1 which are sealed with wolf 2 and in which mercury-containing waste is present (follow-up, complete battery, powder ground fluorescent lamps, catalyst material and the like). Each of the furnaces is connected to its own riser 3, the top of which is connected to a common heat exchanger 4, which is cooled by cooling water and mounted centrally on the distillation vessel 5. There is a connection between the heat exchanger and the distillation vessel. The bottom of the risers 3 comprises a mercury trap 6.

The distillation vessel is connected to the pump 8 via a suction line 7, a water filter 9d is built into the suction line. The atmospheric pressure side of the pump is connected via a line 10 to an oil-to-water separator 11 and .

The furnaces 1 (see Figure 2) have an electrically heatable sheath 14 which is insulated by a sheath consisting, for example, of mineral wool. The removable lid 15, which is capable of sealing the furnace hermetically, is in the form of a cup or dome facing inwardly of the furnace.

The wheels are indicated by 16 and a connection adapter that connects to the riser 2 G ^e indicated at

17. Electrical resistance wires not shown are placed in the sheath 14.

In the plan shown in FIG. 3, the mercury removal unit is marked A, the charging and discharge station is marked B, and the furnace cooling area is marked C.

The mercury-containing drums 18 are ready to be emptied by a mobile crane into the relatively small furnaces 1 from which the lids 2 have been carefully removed from the charging and emptying station B. they are transported to a location around the distillation vessel 5 and each furnace is connected via a riser / heat exchanger 5 to form a bundle.

The vacuum pump 8 is switched on and then the electric heating for the furnaces 11 is switched on. As a result, a vacuum is generated in the furnaces. If the waste is in the form of herring or ground fluorescent tubes or a catalytic material, a vacuum of at least vacuum is required to evaporate the mercury from the waste. 100 mbar and a temperature of at least 360 ° C (for example 400 ° C). Such a vacuum can be achieved using a so-called water ring vacuum pump. A vacuum of at least 10 mbar is required to remove mercury from unground batteries at the same temperature. In this case, the pump 8 is supplemented by the so-called Roots pump.

The vapors from the furnaces 1 first pass to relatively cold risers 3, where a substantial portion of the mercury condenses and flows to the mercury trap 6 from which it can be removed from time to time. The remaining vapors are cooled in a heat exchanger 40, whereby water, light and heavy aromatic compounds and the remainder flow to the distillation vessel. The mercury liquids condense and can be discharged periodically and separately at different levels from the distillation vessel.

To prevent harmful gases from entering the ambient air, the gases drawn from the distillation vessel flow through the water filter 9, the oil-water separator 11 and the activated carbon filters 77. The purified air can then be discharged into the atmosphere without risk.

The dry cleaned products remain in the furnaces 1. After being left in the cooling zone C for some time, the furnaces are

taken back to filling and discharge station B and emptied. Dry cleaned the material is stored in containers 19. From the ground plan in the picture 3 shows that six furnaces se

The risers 3 were placed in a circle around the distillation vessel 5 and formed a bundle. Of course, it is possible to make different bundles of furnaces, risers and distillation vessels connected at the same time and connect them to the same filters 9, 13 and separator 11.

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The most important advantages of the described unit are as follows:

• that batch-to-batch waste treatment results in a situation in which no mercury-containing vapors, such as polluted air, can enter the ambient air; • that cycle time is under control; efficiently and quickly as a result of using relatively small mobile furnaces, • that when a special pump is used, mercury can also be removed from undisturbed batteries.

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-χft · · ftft · ft «ftft · ft mobile furnace lid riser heat exchanger distillation vessel mercury trap suction pipe vacuum pump water filter pipe oil separator water separator activated carbon filter electrically heatable casing removable lid wheel connection socket barrel

A mercury removal unit B charging and discharging stations C furnace cooling area

Claims (8)

PATENT CLAIMS 1. Vacuum distillation mercury removal unit consisting of a sealable chamber in which waste materials may be subjected to elevated temperature and reduced pressure, a vapor removal line from this chamber and a means for cooling the removed vapors and collecting condensed mercury, characterized in that: that the unit comprises at least three electrically heatable, mobile, hermetically sealable furnaces (1) which are connected to form a bundle through the connecting duct (3) and the cooling unit (4) to the distillation vessel (5), the vessel (5) it is connected to a vacuum pump (8). Unit according to claim 1, characterized in that a riser (3) with a mercury trap (6) is incorporated in each connecting pipe between the furnaces (1) and the distillation vessel (5). A unit according to claim 1 or 2, characterized in that said cooling unit (4) consists of a heat exchanger which is mounted on the distillation vessel (5) and can be cooled with cooling water. Unit according to one of the preceding claims, characterized in that the furnace lids (1) are dish-shaped or domed and extend into the furnace (1). Unit according to one of the preceding claims, characterized in that a water filter (9) is incorporated in the duct (10) between the distillation vessel (5) and the vacuum pump (8). Unit according to one of the preceding claims, characterized in that on the outlet side of the pump (8) - an oil-to-water separator (11) and one or more charcoal filters (13) for off-gases are connected in series. Method of removing mercury from waste materials by vacuum distillation using a unit according to one of the preceding claims, characterized in that each of the series of mobile, hermetically sealed furnaces (1) filled with mercury waste is connected via a line (8) to a collection section (1). 6) condensed mercury and a cooling unit (4) into a distillation vessel (5), wherein the temperature in the furnaces is increased to above 360 ° C and a vacuum pump (8) produces a pressure of less than 100 mbar in the distillation vessel (5); a water filter (9), said pipes 3, 7 and 10), a cooling unit (4) and a furnace (1), the condensed mercury is collected in the collection sections and the furnaces (1) are disconnected from the distillation vessel and cooled; ) are removed from them and the furnaces (1) are ready to hold a new charge. The method of claim 7, wherein said vacuum is increased to a value below 10mbar. by