EP1663498B1 - Method for operating a fragmentation system and system therefor - Google Patents

Abstract

A fragmentation system including a reaction vessel with processing fluid and fragmentation product and a pair of electrodes. Two respective ends of the pair of electrodes are arranged at a distance to each other inside the reaction vessel and can be admitted with pulsed high-voltage to grind the fragmentation product positioned in a reaction zone. The system also including a solid/fluid separation device, a suspension device to keep the fragmentation product continually suspended in the processing fluid, and a transfer device to transfer processing fluid and a first share of the fragmentation product out of the reaction vessel to the solid/fluid separation device. A second share of the fragmentation product returns to the reaction zone. The system includes at least one return-flow line coupled to the solid/fluid separation device and the reaction vessel to empty the processing fluid from the solid/fluid separation device into the reaction vessel.

Description

The invention relates to a method for operating a Fragmentieranlage for more effective grinding of Fragmentiergut of mineral and / or brittle materials to target particle sizes <5 mm and a Fragmentieranlage that is operated by this method.

The fragmentation is due to their technical principle on the FRANKA technology (FRANKA = Fr agmentier on location Ka rlsruhe), as in the DE 195 34 232 described. The Fragmentieranlage consists of an electrical energy storage, which is pulsed in a reaction vessel to the Fragmentiergut in a process fluid between two spaced-opposite electrode ends - the reaction zone - is discharged.

During milling with the fragmenting system, the fragmentation material present in the process liquid between the two electrode ends is comminuted by electrical breakdowns and shock waves generated thereby. These mineral and / or brittle materials may be uniform, such as rock / rock or glass, or conglomerated, such as rock and concrete. The target grain sizes are <5 mm, preferably even <2 mm. Fragmented particles below this particle size are sucked out of the process area via filter cartridges. See, for example, gravel and sand extraction or grinding of color bodies, more generally non-composites. Fragments, such as those obtained when a building is demolished, are constantly refilled into the process area, oriented on the extracted fragmentation material.

The Fragmentieranlage consists of an electrical energy storage, which is discharged via a spark gap impulsively to a load. The load is the process fluid in the interelectrode region and the fragmentation material buried therein. The two electrodes are located therein, completely immersed with its respective end, on a predetermined n, adjustable spacing. Usually, the process fluid taken in the reaction vessel, in which the Fragmentiergut poured into it and the fragmented Good is taken off and below the predetermined threshold for the grain size.

So far, it is assumed that the ground material due to the discharges between the two ends of the electrode, which are usually the high voltage electrode and the bottom or a portion thereof, the material to be ground in the pulse discharges is always sufficiently strong swirled. However, test series have shown that the whirling up is very incomplete.

The SU 888 355 A1 discloses an electrodynamic fragmenting apparatus in which lumpy material is fragmented over a perforated bottom, the perforation of the bottom serving as a water purging from below. Sufficient shredded material is carried along by the upwardly flowing water. A sieve in the upward stream will only pass grain at or below target size. Too large grain, which is also carried by the water stream, gets stuck in front of the stream, is discharged and fed again together with fresh feed to the reaction zone.

In the US 3,715,082 A there is described an electrohydraulic fragmenting apparatus in which the material to be fragmented slides down the bottom of a sloped pipe, the chute, with the bottom of the pipe perforated to peel target size grain. In the material flow protrude a plurality of horizontally or vertically arranged pairs of electrodes. When sliding down the chute, the material is successively fragmented and a stratification is formed: the finest material accumulates on the ground, progressively coarser layers accumulate over it.

This led to the object underlying the invention, namely to hold the introduced into the electrode gap Fragmentiergut by levitating more effectively to save process time and energy.

This object is procedurally achieved by the step characterized in the first claim of the Aufwirbelung of Fragmentierguts in the filled with process liquid space between the electrode ends and the settled at the bottom of the reaction vessel Fragmentierguts. The Fragmentiergut located in the process liquid is constantly held in suspension and thus forms a suspension with the process liquid. From this suspension, the proportion of processed Fragmentierguts that has reached or fallen below the target grain size, discharged from the reaction vessel and the Zielkorngröße exceeding Fragmentiergut - which are the coarse fractions - again fed to the reaction zone.

Objectively, this object is achieved by a fragmentation system according to the characterizing features of claim 2 . Attached to or into the reaction vessel, a device containing the fragmentation material suspended in the process liquid is suspended, since no air, relative dielectric constant ε _r near 1, or no gas, ε _r , may be introduced into the process space. Furthermore, a device is mounted on or in the reaction vessel, the the suspension, the fragmentation product, and rejects them below the target particle size, means for supplying lüssig F Estonia F separation and returns fragmentation product above this target particle size in the reaction vessel. For this purpose, at least one return line for process liquid opens into the reaction vessel.

To keep the fragmentation product effectively in suspension, are hydrodynamic such streams, or mechanical means such as ühren R or S chaufeln suitable. Flow direction and strength as well as stirring and blade speed can be controlled and adjusted to optimize fragmentation.

According to the invention, filters immersed in the process liquid in the reactor, such as filter baskets or filter cartridges, are used for the separation.

For an economical continuous operation of the Fragmentieranlage the maintenance of the suspension is important. The device for this purpose must be set up and adjusted so that the fragmentation material in the process fluid is kept in suspension without the formation of dead zones.

According to the invention, such devices from the screening technology known filters in the form of baskets, cartridges, for example, w obei then due to the shock wave due to the electrical discharge, the distance to the electrode gap cleaning and destruction is set to avoid. The intensity decreases with 1 / r ² from the shockwave source.

Inlet nozzles through which / is flowed controlled initiated the process liquid lüssig separation recovered in Estonia F F into the reaction vessel and directed to hold according to claim 3 the suspension upright.

As a result of these measures, fines of the millbase can be kept in suspension during the fragmentation in the process fluid and repeatedly returned to the electrical discharge area. The suction cartridge or the suction cartridges are seated in such a way that the fragmented material is likely to hit them and the sufficiently small particle sizes are sucked out. During each discharge process, fragments still hanging on the sieve of the suction cartridge are shaken off by the shock wave / s triggered by the discharge channel (s).

In the following , the method and an exemplary fragmenting system will be explained in more detail with reference to the drawing. An embodiment will be described, namely the embodiment "loop"
, It is a fluidically favorable solution after preliminary investigations. Further variants of the solution can be seen in a directional pipe or tube bundle. In any case, care must be taken during the design and construction of the plant to avoid dead flow areas where fine fractions would accumulate and deposit.

From the Fragmentieranlage only the reaction vessel itself is shown. The electrical part, the charger, the energy storage and the spark gap are u.a. devices known from the above-cited prior art. Predominantly, the electrical energy store is a capacitor bank, which is discharged with interposed spark gaps in the self-breakdown of the load in the inter-electrode space in the reaction vessel. In systems of the FRANKA type, the electrical part is a Marx generator whose electrical charging and discharging from the high power electrical / voltage pulse technology is known.

The figure shows the barrel-shaped reaction vessel standing on supports. The high-voltage electrode, which is electrically insulated up to its free end region, projects into the interior of the reaction vessel through the lid. The high voltage electrode is not rigidly guided in the lid so that shock and shock wave action resulting from electrical discharge can not be transmitted. The bare metal end region is completely submerged in the process liquid taken in the reaction vessel, which is water here. Even the insulation sheath sticks out far into the water. On him no creepage distances may be formed in long-term operation. The counterelectrode is here, for example, spherically lowered bottom of the reaction vessel itself. This can be the entire floor or just a central part of it. In any case, the counter electrode is connected to a fixed potential, the reference potential, in the general ground potential. On the ground potential electrode, centrally deposited, Fragmentiergut indicated. The discharge channel should form, starting from the top of the cooking voltage electrode, through the material to be fragmented through to the ground potential electrode, or should form a conical region of discharge channels from the front of the high-voltage electrode to the central bottom region.

Through the lid of the reaction vessel en rag the water feed line and the discharge line for the fragmentation product with water from the offset Filter cartridge. To r optimization of the fractionation, the flow, which provides for the fluidizing, is controlled in its thickness and at its flow beginning in the direction. This device for generating flow and resuspension of Fragmentierguts here surrounds the high voltage electrode coaxial. The supply line feeds into the coaxially seated ring line. The loop is electrically safe and, shock waves with tolerable effort, mounted on the vessel wall.

The nozzles can be aligned in their outflow direction so that, depending on the material to be fragmented, process-optimal fluidization can be set or readjusted. The flow rate is adjusted with a pump, which presses the pure process liquid into the loop. The nozzles direct the currents at the bottom to the floor center. The settled there or settling Fragmentiergut is so constantly stirred up and kept in suspension. Flowless areas are avoided throughout the water volume.

The filter cartridge is completely submerged in water. The grid surrounding the filter cartridge determines with its mesh size the largest extractable grain size. The suspension passing through the filter cartridge is separated into its liquid component, the process water, and its solid components in the centrifuge indicated on the right in the image. The water is returned via the supply line to the loop in the reaction zone , possibly previously mixed with fresh water, returned.

About the left in the image of the reaction vessel protruding neck is refilled to be fragmented Good / tilted.

Depending on the size of the reaction vessel, it is a considerable relief during maintenance and repair work, when the bottom of the reaction vessel unscrewed and on the boom, which rotatably supports on the right support in the image, can be turned away.

Claims (3)

1. Method for operating a fragmentation system for the more effective grinding of mineral and/or brittle materials to target particle sizes of < 5 mm, wherein the fragmentation system comprises an electric energy store which is discharged in a reaction vessel in a pulse-like manner onto the fragmentation product in a process fluid between two electrode ends that are situated opposite each other at a spacing - the reaction zone -, and wherein the fragmentation product situated in the process fluid is kept constantly suspended in a hydro-dynamic or mechanical manner and consequently forms a suspension with the process fluid, characterized in that the fragmentation product in the reaction zone filled with process fluid and the fragmentation product deposited on the bottom of the reaction vessel is swirled up, from this suspension the proportion of the processed fragmentation product that has obtained or fallen below the target particle size in the reaction vessel is discharged through filters immersed into the process fluid and the fragmentation product exceeding the target particle size - that is the coarse parts - is returned back into the reaction zone from the surface of the filter.
2. Fragmentation system for accomplishing the method according to Claim 1, said fragmentation system comprising a chargeable electric energy store, a pair of electrodes connected thereto, the two ends of which are situated opposite each other at a spacing in a process fluid that is contained in a reaction vessel, wherein one of the two electrode ends is on reference potential and the other - the high voltage electrode - can be acted upon with high voltage in a pulse-like manner from the energy store via an output switch, and wherein a device that keeps the fragmentation product introduced in the process fluid in a suspended manner without the formation of dead regions is mounted on or in the reaction vessel, characterized in that a filter, which takes the targeted particle size into account and is completely immersed into the process fluid, is mounted on or in the reaction vessel as the device which conducts the fragmentation product parts at and below the targeted particle size out of the suspension and supplies them to a device for solid-fluid separation and returns fragmentation product parts that are above said particle target size back into the reaction zone and at least one return line for process fluid opens out into the reaction zone.
3. Fragmentation system according to Claim 2, characterized in that the process fluid from the solid-fluid separation is returned into the reaction zone in such a manner through one or more nozzles that the process product in the reaction zone is kept as completely as possible in a suspended manner.

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