DE8710825U1 - Device for separating pollutants from contaminated soil - Google Patents

Description

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I The innovation concerns a device for

I Separation of pollutants from contaminated soil

I with a storage tank in front of an inlet lock

I for the contaminated soil and a

^f Outlet lock for cleaned soil components

j. and a supply line for a

I cleaning solution and with a collecting line for

I a mixture of solution and pollutants

I solution mixture.

I &igr;/ In the unpublished, older

I German patent application P 36 10 199.5 is a

I procedure has been proposed by which the

■| Bottom of a countercurrent extraction with at least

\ a solvent that dissolves the pollutants

i , whereby in a

&ldquo;&iacgr; Countercurrent extractor the solvent from a

I end and the floor to be cleaned from the other end

I introduced and at the opposite

; end to be executed.

A device of the type mentioned above with such a countercurrent extractor is disclosed in the unpublished German patent application P 36 10 113.3. This countercurrent extractor consists of a rotatable

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Drum housing with conveyor screws running through both ends, of which the conveyor screw located at the low end is intended to remove the soil to be cleaned and the conveyor screw located at the high end is intended to remove the cleaned soil, which still contains solvents. The solution for cleaning the soil is guided concentrically through the latter screw and flows from a feed line at the upper end of the rotating drum housing into the countercurrent extractor.

This device has the disadvantage that the mixing of the solution and the soil to be cleaned and the residence time of these substances in the extractor are too short. As a result, the degree of cleaning of the contaminated soil after passing through this countercurrent extraction neither meets the expectations nor the official requirements that are placed on the degree of cleanliness of such soils before they are brought to their destination.

With a known device of a different type (on-site soil cleaning according to the Oil-Crep system from "wlb = water, air and operation" - 10/86/ page 59/61) the treated soil is mixed with water in a

Four-chamber countercurrent turboflotation, so that oil and grease contamination is dissolved and washed away with a cold high-pressure water jet. This procedure could previously only be used on oil-treated floors at

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a low throughput of 5 in ³ to 15 m ³ of soil per hour. Due to this low throughput, this process is uneconomical and its application and effectiveness on pollutants other than oil is questionable.

And finally, a device for thermal cleaning is known in which the contaminated soil is exposed to very high temperatures in incinerators, whereby the pollutants are converted into harmless compounds such as carbon dioxide and water. This process requires a lot of energy, has extremely high operating costs and has the disadvantage that |

the cleaned soil no longer contains any organic components after this treatment and is therefore biologically dead. This soil must therefore be mixed with untreated soil, which involves additional costs.

Based on this state of the art, the innovation is based on the task of creating a device of the type mentioned at the beginning, with which contaminated soils can be decontaminated to the desired degree of purity in a cost-effective manner with a high throughput volume per unit of time.

This task is solved in connection with the generic term mentioned at the beginning in accordance with the innovation by installing several washing drums, each forming a stage, behind the inlet lock

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are arranged one behind the other, each of which consists of a stationary drum housing inclined at an angle to the horizontal with an inlet nozzle at the low end and an outlet nozzle at the high end and a belt screw that can rotate in it and is provided with a drive unit, which is separated from a collecting space in the drum housing by a sieve, with the outlet nozzle of a drum housing being directly connected to the inlet nozzle of the drum housing of the downstream washing drum and an agitator being arranged at the low end. This arrangement enables extremely effective step-by-step cleaning with a continuous throughput of the soils to be cleaned, with the percentage cleaning effect being greatest in the first stages and lowest in the last stages. For this reason, it is sensible to only choose as many washing drums arranged one behind the other as the desired degree of purity of the soil components requires.

Consequently, the number of washing drums to be arranged in series must be selected depending on the variable sizes of the degree of contamination, the desired degree of cleaning of the soil components and the type of solvent and pollutants.

To ensure the most intensive mixing possible before entering the first washing drum , this is a homogenization container

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which is located directly behind the inlet lock. This homogenization container advantageously consists of a pear-shaped mixing drum, built on the principle of a concrete mixer, with a drive and a change-over gear, at the opening of which an axial inlet and a radial outlet pipe are arranged in an airtight manner. This allows the material from a storage container to be fed into the

The soils entering the homogenization tank are intensively mixed with the solution pumped into the interior and are saturated until the direction of rotation of the homogenization tank is changed by operating the switching gear and this mixture reaches the first stage via the radial outlet pipe. In order to leave as much of the solution mixture as possible in the mixing drum, it is equipped with a drain screw.

In order to be able to clean the soils to be cleaned with a high degree of efficiency, a crusher for processing the contaminated soils to a droppings size in a range of approx. 2 mm to 30 mm and/or a drying device for removing liquid components, in particular water, from the contaminated soils are arranged in front of the homogenization container.

The outlet nozzle of the last washing drum is connected to the inlet nozzle of a drying screw via a cross conveyor according to an advantageous further development of the innovation*

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behind the outlet nozzle of their housing the
Outlet lock is arranged. In this
Dry screw can still be used with solution,
solvent mixture and/or water,
cleaned soil components are dried/
before they are finally cleaned and
Leave the exit lock and at the desired
steep, e.g. at their extraction point, again
can be introduced.

Since the inlet port of each stage
fresh solution added for further cleaning
is an intensive
Mixing desirable and therefore also in the
Near the inlet nozzle of each washing drum

a stirrer is arranged. In addition, each |

Collection room of the washing drums near his |

low end has an overflow that goes over I

an intermediate line with the collecting line for the ?

solution mixture is connected. via this I

Overflow, the intermediate line and the

Collective line is the one with the \

Contaminant concentrate solution mixture j

according to the inflow of fresh solution to the |

individual washing drums and the I

Homogenization tank also continuous |

deducted. |

The collecting line carries the solution mixture f

i via a double filter to a storage tank, i

whose outlet line via a heat exchanger
is connected to an evaporator whose j·

Outlet pipe together with one from the j

Housing of the drying screw

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Gas collection line is led via the heat exchanger to a condenser. This arrangement means that the solution mixture is preheated before reaching the evaporator by the amount of enthalpy which the evaporated solution has given off to the heat exchanger, which acts as a preheater, before reaching the condenser. The radiation losses should be considered to be negligibly small.

The solution emerging from the condenser is fed into a receiving tank, which in turn is connected to a storage tank, whereby the solution collected in the receiving tank can be pumped by a pump via the feed line and connected branch lines to the inlet pipe of the homogenization tank and to the inlet nozzles of the drum housings of the individual washing drums. This arrangement means that the solution is constantly recovered and its losses are replenished from the storage tank. This means that essentially the same solvent is always used to clean the contaminated soil, the pollutant condensate is removed at the evaporator, the solution vapors are condensed in the condenser and the condensed and now cleaned solution is returned to its intended purpose. This measure also makes the innovative process extremely cost-effective.

The pollutant concentrate collected in a sump at the bottom of the evaporator flows into a

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from where it is pumped into a transport container for ^further disposal. This small volume pollutant concentrate can then be sent either to a landfill or to a

High temperature incineration plant.

The new device is described below using the drawings. These show:

Figure 1 a homogenization tank, three washing drums arranged one behind the other and a drying screw for cleaning solids and

Figure 2 shows a device for evaporating the solution mixture, distilling the pollutant concentrate and condensing the solution.

In Figures 1 and 2, the line ends (A, B, C) of Figure 1 are to be connected to the correspondingly marked line ends of Figure 2 to form a common device.

The new device essentially consists of three device groups, of which the device group (1) according to Figure 1 for solids cleaning and according to Figure 2 the device group (2) for evaporation of the

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The device group (4) according to Figure 2 is a vacuum device for generating a vacuum and thus for removing all apparatus containing solution vapors.

The device group (1) for

Solids cleaning essentially consists of the komogenization tank (5) and three downstream washing drums (6, 7, 8), each of which consists of a fixed
Drum housing (9, 10, 11) with an inlet connection (12, 13, 14) at the low end (15, 16, 17) and with an outlet connection (18, 19, 20) at the high end (21, 22, 23) and a screw conveyor (27, 28, 29) rotatable therein and provided with a drive unit (24, 25, 26), which is separated from a collecting chamber (33, 34, 35) of the drum housing (9, 10, 11) by a sieve (30, 31, 32). The outlet connection (18) of the drum housing (9) is directly connected to the inlet connection (13) of the drum housing (10) of the downstream washing drum (7). The outlet connection (19) of the drum housing (10) is also connected to the inlet connection (14) of the drum housing (11). An agitator (36, 37, 38) is arranged at the low end (15, 16, 17) of each drum housing (9, 10, 11).

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The outlet connection (20) of the last washing drum (8) is connected via a cross conveyor (39) to the inlet connection (40) of a housing (41) of a drying screw (42), with the outlet lock (44) being arranged behind the outlet connection (43) of the latter.

The cleaned and dried soil components emerging from the outlet lock (44) are loaded onto a transport vehicle (not shown) by a conveyor belt (45), and contaminated soil (47) is transported via a further conveyor belt (46) into a storage container (48), at the outlet of which the inlet lock (49) is arranged.

The inlet lock (49) and the

Outlet locks (44) prevent air from entering the device group (1) for solids cleaning.

After passing the inlet lock (49), the contaminated soil enters the
Homogenization tank (5). This homogenization tank (5) consists of a pear-shaped mixing drum (53) constructed according to the principle of a concrete mixer, having a drive (51) with a changeover gear (52), at the opening (54) of which a radial outlet pipe (55) is arranged in addition to the axial inlet pipe (50). The n-pentane, for example, is fed via the feed line (56) and the branch line (57).

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The solution consisting of petroleum ether or hexane is fed together with the contaminated soil (47) through the axial inlet pipe (50) into the interior of the mixing drum (53). There, the solution and the contaminated soil (47) are mixed intensively. After sufficient mixing, the switching gear (52) is activated and the direction of rotation of the mixing drum (53) is reversed. The contaminated soil components saturated with the solution are then transported upwards via the drain screw (58) and reach the inlet nozzle (12) of the first washing drum (6) through the radial outlet pipe (55). There, they are collected in the sump of solution and contaminated I at the low end (15).

Soil is intensively mixed by the agitator (36). |

At the same time, the drive (24) rotates the belt screw (27). This causes the mixture of solution and contaminated soil to be conveyed diagonally upwards towards the outlet nozzle (18) of the washing drum (6). Since a sieve (30, 31, 32) is arranged under each belt screw (27, 28, 29), the soil components are largely freed from the solution mixture and sieved off during their upward movement. The process described above is repeated twice more in the downstream washing drums (7 and 8). The cleaned soil components then reach the drying chamber (42), where they are freed from the residual solvents and water - also with the addition of heat - before they pass through the outlet lock (44) to the device chamber (1) for cleaning solids.

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In addition to the branch line (57) to the homogenization tank (5), two further branch lines (59, 60) branch off from the supply line (56) for the solution, the first of which leads to the inlet connection (13) of the washing drum (7) and the second to the inlet connection (14) of the washing drum (8).

At the lowest end of each collecting chamber (33, 34, 35) of the individual washing drums (6, 7, 8)

Intermediate lines (61, 62, 63) are connected, which lead the solution mixture loaded with pollutants to the collecting line (64). The collection line (64) is connected via a double filter (65) to a storage tank (66), the outlet line (67) of which leads via an intermediate pump (69), a line (68/ and a heat exchanger (70) as well as the connecting line (71) to the evaporator (72), the evaporator (72) is supplied with high-temperature oil via the connections (73). The solution vapor then generated escapes via its outlet line (74) and flows together with a gas collection line (75) from the housing (41) of the dry screw (42) into the heat exchanger (70), from which the solution vapor, which is thereby partially cooled, reaches the condenser (77) via the intermediate line (76). The water content condensed together with the solution in the condenser (77) is in a Capacitor (77)

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separated by a downstream water separator (78) and pumped out via the line (79) and a collecting container (80) using the pump (81).

The solution freed from water in the water separator (78) then passes via the line (82) into a storage tank (83).

Since the solution in the storage tank (83) cannot be completely recovered for various reasons, the lost portion must be replaced by a corresponding portion of fresh solution. This is done by connecting a storage tank (84) to the storage tank (83) via the line (85).

From the storage tank (83) the solution is fed again to the homogenization tank (5) and the individual washing drums (6, 7, 8) via the pump (86) and the feed line (56) in the manner described above.

The pollutant concentrate collected in a sump at the bottom (87) of the evaporator (72) flows via the line (88) into the storage tank (89) and is pumped from there into a transport container (91) by means of the pump (90).

All storage tanks, namely the storage tank (66) according to Figure 1 and the two additional storage tanks (83 and 89) according to Figure are connected via lines (92, 93/ 94) to the

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Line (95) of the vacuum device in a connection that drains all solution vapors* Via the line (95) these vapors pass through a vacuum pump (96) into a line (97) filled with sealing liquid and a separator (98) into a cooling filter system (99) so that any oil or solvent particles that may be entrained do not get into the system. (100/ x3c designates an air cooler* On the one hand, the flow of the contaminated solution mixture from the

Washing drums (6, 7, 8) supported and at the same time - _r

the distillation gases of the solution from the evaporator (72), from the housing (41) of the drying screw (42) and from all

storage containers (66, 83, 89) and their |

Escape to the outside air is prevented. Ultimately,

by evacuating the

Device groups (1, 2 and 3) also the j

Risk of explosion within the system reduced.

All device groups (1, 2, 3 and 4) of the new device can be dismantled according to a modular principle and reassembled at any location.

For energy supply, which is not the subject of the present innovation, a high-temperature oil heater operated with light heating oil, gas or similar fuels is available, which supplies the evaporator (72) and the housing (41) of the drying screw (42) with thermal energy.

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The cooling of the distillation gases from the solution is carried out by a cooling water circuit, which is also not the subject of the present innovation. In order to be independent of the local water network, this cooling water circuit can be connected to a cooling system and a storage tank, which ensure the required cooling water temperature even on warmer days.

The electrical supply of all device groups (1, 2, 3, 4) and their control are carried out by a central control cabinet (not shown).

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List of reference symbols

Cable ends

fler Figure 1 AB

Device group Ifiomogenization tank lia sch drum frommel housing inlet nozzle

low end of drum housing

Outlet nozzle

high end of drum housing

Drive unit fine screw sieve

Gathering room

9 10 11

12 13 14

15 16 17

18 19 20

21 22 23

24 25 26

27 28 29

30 31 32

33 34 35

Agitator 36 37

38

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Housing of
Dry screw 42

Dry screw

Outlet nozzle from
Dry shricckc 42

Outlet lock

Conveyor belt

contaminated soil storage tank

Inlet lock

axial inlet pipe

drive

Gearbox

Mixing drum

39

41 42

43

44

45 4g

47

48

49

50

51

52

53

Opening in mixing drum 53 54 radial outlet pipe

55

Supply line

56

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Branch 57 59

Drip screw 58

Intermediate lines 61 62 63

Collective line 64

Double filter 65

Storage tank 66 83

Outlet line from storage tank 66 67

Line 68 79 82

88 92 93 95

Pump 69 81 86

Heat exchanger 70

Connection management 71 Evaporator 72 connections 73 Outlet line from
Evaporator 72 74 Gas collection line 75 Kondehaatoii 77

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Water separator 78

Collection container 80

Bottom of the evaporator 72 87

Transport container 91

Vacuum pump 9 6

with sealing fluid

filled line 97

Separator 98

Recooling filter system 99 air cooler

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Claims (1)

kre 876a/87 Protection claims: 1. Device for separating pollutants from contaminated soils with a storage container in front of an inlet lock for the contaminated soils and an outlet lock for cleaned soil components as well as with a feed line for a cleaning solution and with a collecting drain for a solution mixture consisting of solution and pollutants characterized in that behind the inlet lock (49) several washing drums (6, 7, 8) each forming a stage are arranged one behind the other, each of which consists of a « stationary drum housing (9, 10, 11) inclined at an angle to the horizontal with an inlet connection (12, 13, 14) at the low end (15, 16, 17) and with an outlet connection (18, 19, 20) at the high end (21, 22, 23) and of a rotating a drive unit (24, 25, 26) belt screw (27, 28, 29) which is separated by a sieve (30, 31 32) from a collecting chamber (33, 34, 35) de3 drum housing (9, 10, 11), wherein the outlet connection (18, 19, 20) of a drum housing (6, 7) is directly connected to the inlet connection (13, 14) of the A stirrer (36/ 37 _f 38) is arranged in each case between the drum housing (10, 11) of the downstream washing drum (7, 8) and at the low end (15, 16, 17). kre 876a/87 2. Device according to claim 1, characterized in that between the inlet lock (49) and the first washing drum (6) a
Homogenization container (5) is arranged. 3. Device according to claim 2, characterized in that the homogenization container (5) consists of a pear-shaped mixing drum (53) constructed according to the principle of a concrete mixer, provided with a drive (51) and a changeover gear (52), at the opening (54) of which an axial inlet pipe (50) and a radial outlet pipe (55) are arranged in an airtight manner. 4. Device according to one of claims 1 to 3, characterized characterized in that a drip screw (58) is arranged in the mixing drum (53). 5. Device according to one of claims to 4, characterized characterized in that a crusher for processing the contaminated soil to a grain size in a range of approximately 2 mm to 30 mm and/or a drying device for removing liquid components from the contaminated soil are arranged in front of the homogenization container (5). kre 876a/87 44 · * t I · 1«·· · I t t « * # ·« ta« · til it«· << 6. Device according to one of claims 1 to 5, characterized characterized in that the number of ¹ series-connected Washing drums (6/ &Iacgr;, 8) according to the required degree of purity of the cleaned soil components uiiu imi.ii UCiIi i\t»ii uaiiixiixcL· unyayt au cjtJL Duuen is aligned. 7* Device according to one of claims 1 to 6, characterized
characterized because the
Outlet nozzle (20) of the last washing drum (8) via a cross conveyor (39) with the
Inlet connection (40) of a drying screw (41, 42), behind the outlet connection (43) of its housing (41) the outlet lock (44) is arranged. 8. Device according to one of claims 1 | fs up to 7, thereby | I know that every &psgr; U collecting chamber (33, 34, 35) of the |&kgr; W washing drums (6, 7, 8) near its | has an overflow at the low end, which is connected via an intermediate line (61, 62, 63) to the collecting line (64) for the solution mixture. kre 876a/87 5. Device according to one of claims 1 to 8/ characterized characterized in that the collecting line (64) leads via a double filter (65) to a storage tank (66), the outlet line (67) of which is connected via a
Heat exchanger (70) is connected to an evaporator (72), the output line (74) of which is connected together with a heat exchanger on the housing (41) of the | Dry screw (42) I Gas collection line (75) via the Heat exchanger (70) is led to a condenser (77). 10. Device according to one of claims 1 to 9, thereby « characterized in that the from the | The solution leaving the condenser (77) is led into a storage tank (83) which in turn is connected to a reservoir (84), the solution collected in the storage tank (83) being pumped by a pump (86) via the supply line (56) and the associated | Branch lines (57, 59, 60) to the inlet pipe (50) of the homogenization container (5) and to the inlet nozzles (13, 14) of the drum housings (10, 11) of the washing drums (7, 8) can be pumped. kire 876a/87 11* Device according to one of claims 1 to 12/ characterized characterized in that the pollutant concentrate collected in a sump at the bottom (87) of the evaporator (72) flows into a storage container (89) and from there can be conveyed by means of a pump (90) into a transport container (91) for further disposal. 12. Device according to one of claims 1 to 11, characterized fe indicates that all storage containers (66, 83, 89) are connected to a vacuum device (4) having a vacuum pump (96), an air cooler (100) and a separator (98) for discharging solution vapors. 13. Device according to one of claims 1 to 12, characterized fe indicates that all device groups (1, 2, 3, 4) of the device can be dismantled according to a modular principle and reassembled at any location. 14. Device according to one of claims 1 to 3, characterized fe indicates that the solution for cleaning soils contaminated with aliphatic, aromatic and/or halogenated hydrocarbons consists of n-pentane, petroleum ether, hexane or the like.