CN1169706A

CN1169706A - Method and equipment for the purification of a liquid

Info

Publication number: CN1169706A
Application number: CN 95196728
Authority: CN
Inventors: N·汉列克森
Original assignee: Mastrans AS
Current assignee: Mastrans AS
Priority date: 1994-10-19
Filing date: 1995-10-06
Publication date: 1998-01-07

Abstract

The present invention provide a method and equipment for purification of a liquid, wherein the liquid is polluted by other liquids or solid material, e.g. removing oil from oil contained water, comprising a flocculation device (2) and a flotation device (8). The method comprises adding one or more chemicals to the liquid in a flocculation device that comprises one or more pipe loops (2) with built-in agitators (3, 20, 21) providing turbulence and plug-type flow through the loop. Thereupon purified liquid and pollutants are separated in the flotation device or in a sedimentation device (8). The equipment according to the invention comprises a pipe loop (2), provided with built-in agitator(s) (3, 20, 21), connected to the flotation device (8).

Description

The method and apparatus of decontaminating liquid

The present invention relates to the method and apparatus of decontaminating liquid, this liquid may be polluted by other liquid or solid material, for example removes from water and deoils, and comprises flotation unit.

The producing oil conductance causes and produces a large amount of butyraceous seawater near seashore.The major portion of oil can be separated with seawater in separation vessel or separating tank, but that this cleaning action is not enough to make seawater to turn back to is marine.At present, the regulation of authorities points out that the water oleaginousness of overflowing near seashore the oil gas device should not surpass 40ppm.

From water, remove and deoil and/or during other pollutent, often have several different methods to adopt whizzer, wet cyclone and flotation unit (flotation installation).

Whizzer provides the sophisticated machine of high purification, but its specific storage (specificcapacity) is low.Use this class refining plant to comprise many parallel connected machines during producing oil.This device is very expensive, and need have large quantities of spare parts.Daily maintenance also comprises many contents.

Another shortcoming is that this class device quite consumes energy.Typical case's energy consumption is that 1 kilowatt-hour/cubic meter is purified waste water.

Wet cyclone can be regarded " ordinary skill " as, because they are optimized for (platform installation) in the new stage apparatus.These separators have quite excellent performance under favourable working conditions.Yet they also have some limitations and shortcoming.When having little oil droplet, the chemical flocculation device must be set in the upstream of spinning liquid tripping device.The shearing force that can produce in wet cyclone is very big, so flocculus (flake) must be very solid.Flocculus with desirable strength may be difficult to produce.

And the pressure in the wet cyclone falls very big, generally greater than 40m.W.P.

When release, need jumbo flotation cell (flotationchamber) in the downstream of wet cyclone.According to some working conditions, the installation of spinning liquid tripping device may be very loaded down with trivial details.The capacity of wet cyclone is little, and therefore when requiring higher capacity, they must connect as big complexes on one group one group ground.

The 3rd class tripping device, promptly flotation unit is characterized in that their specific storage and decontamination effect improving are all low.This class device requisite space is big, also usually is difficult to operation.At present, flotation unit is considered " technology in past ", because what use is many shortcomings of this device almost do not have near seashore.

The present invention can regard a kind of flotation unit as, but it has substantial improvement project in these areas.Therefore, device of the present invention needs little space and volume, and the specific rotation liquid separating apparatus is significantly lighter and better decontamination effect improving arranged.

According to a kind of method, the invention is characterized in that scavenging process comprises to one or more chemical of contaminated liquid adding that place flocculation plant.Flocculation plant is made up of one or more endless tube that built-in agitator is arranged (pipe loop), and built-in agitator produces turbulent flow and the piston flow by endless tube, then the liquid and the pollutent of isolation of purified in flotation unit or settler.

Equipment of the present invention is characterised in that it comprises the endless tube with built-in agitator that links to each other with flotation unit.Claim 3-10 illustrates superior characteristics of the present invention.

Following accompanying drawing with reference to the explanation embodiment of the present invention is described the present invention in detail:

Fig. 1 is the synoptic diagram of liquid cleaning device of the present invention;

Fig. 2 is the synoptic diagram of another embodiment of Fig. 1 device;

Fig. 3 is the agitator enlarged view among the present invention illustrated in figures 1 and 2;

Fig. 4 is the similar agitator of the another kind of drive unit of band of same ratio.

As depicted in figs. 1 and 2, device mainly is made up of guard system or endless tube 1, and comprising riser components 2, bubbling producer, for example static mixer 5, and flotation unit or settler 8.

As shown in Figure 1, pending liquid is by in the conduit component 2 that the chemical flocculation effect wherein takes place.The flocculation chemical is supplied with by connecting tube 4.

Every conduit component all has built-in agitator (Fig. 3), and it comprises the axle 20 of penetration piece, and axle has propeller parts 21 and pedestal bearing 22.Agitator is by the speed drive of motor 3 to suit.The volume of pipeline is suitable for having time enough to obtain enough flocculus of size.

For reducing liquid in ducted rotation, pipeline has static guide vane 23 between the propeller parts.

Propeller 21 and guide vane 23 are designed to obtain required turbulent flow, and liquid is with piston flow form motion, and do not have excessive shearing force.

The experiment of pilot plant shows, and the decontamination effect improving from water during separating oil is very satisfactory, that is to say, when agitator directly is connected to the flotation unit that forms flotation cell, is lower than 5ppm.

Yet, decide by the pollutant type that may exist, and in some cases, be further to improve purifying method, need be in foregoing bubbling producer air supply or other gas.

In the end in embodiment, as depicted in figs. 1 and 2, when flocculus formed, air or gas for example were to supply with under the support of a cover static mixer by pipeline 1 and at the bubbling producer, form the bubble of wishing size and quantity.

The required gas of flotation also can directly be supplied with last flocculation conduit component, does not preferably adopt any bubbling producer.Liquid-flow in the conduit component should be upwards (not signal).Utilize built-in agitator and guide vane to produce the bubble of suitable size.

Static mixer 5 can be placed in the pipe connecting that flocculates between pipe 2 and the scatterer 6 as shown in Figure 2, or is placed in the outer pipeline 14.

The liquid that comprises bubble and flocculus is by scatterer 6, make liquid enter flotation cell 8 before speed significantly reduce.

Coalescer (bubble withdrawer (bubble retriever)) 9 places flotation cell, and coalescer comprises the plate (lamella) of horizontal positioned, and they cover the whole width of flotation cell.Plate is made by flat board or corrugated plate, and the vertical range of setting for example is 10-100mm.

The flocculus and the liquid that have reclaimed bubble pass through coalescer with laminar flow together, will stick on the plate successively then.

In this mode, when flocculus became enough big, they were just evicted from coalescer by liquid stream, and rise to the surface of flotation cell rapidly.Afloat gas is emitted by pipe 12, and decontaminating liquid is last through managing 10 dischargings, and isolated flocculus is got rid of through managing 11 in some liquid.

Dividing plate 16 is placed in the flotation cell, to define two independently chambers, is respectively applied for the liquid of purification and skims oily liquid.

The length of plate makes even minimum flocculus also is recovered in the coalescer.Distance between the outlet of coalescer 9 and the dividing plate 16 is suitable for flocculus has time enough to rise to flow surface.

The method of available routine is controlled quantity purification and that skim the liquid of oil of discharge, and these methods are not described further at this.

Fig. 4 represents this unitary another motor of operation, and wherein liquid stream sprays the turbine 18 that links to each other with agitator to drive by nozzle 17.

The technological merit of flocculation system may be summarized as follows:

The shearing force that flocculation process is piston flow, ideal stirring and turbulent flow, may destroy flocculus is restricted, adds on the position that quantity is not limit in the optimum time factor optimizations such as chemical.

And the technological merit of flotation unit may be summarized as follows:

This device makes can optimum quantity and bubble size supply gas/air.Utilize scatterer and coalescer system, it is very effective that floatation process becomes, and the flotation cell surface-area becomes seldom: high loading cubic meter/square metre, hour.Experiment:

Experimentize with the butyraceous seawater, the water yield is about 4000 liters/hour, and the oil-contg in sample water is about 1000mg/L.The mean size of oil droplet is 5mg, and the pH value of seawater is 6.2.Add two kinds of chemical A and B, every kind of chemical reaction times was respectively about 45 seconds.Add about 0.1 liter of flotation gas/premium on currency, technology. the about 1 crust absolute pressure of pressure process.Experimental result shows, has reduced the oil mass in the water, is equivalent to remaining oil and is lower than 5mg/L.

The present invention as claims definition is not limited to above-mentioned embodiment.Therefore, endless tube 2 can comprise the pipe of level or inclination, rather than the pipe of vertically laying.In addition, the bubbling producer can be made up of the one or more gas jets that are placed in bubble-chamber rather than the static mixer.Possible is that the bubbling producer can directly be carried the blended gas/water to flotation unit.Plate in the coalescer can be corrugated, and is adhered in its surface to prevent oil by for example PTEE (tetrafluoroethylene) coating.

Claims

1. the method for decontaminating liquid, wherein liquid is polluted by other liquid or solid material, for example deoiled from removing the water of oil pollution, comprise flocculation plant (2) and flotation unit (8), it is characterized in that the liquid in flocculation plant adds one or more chemical, flocculation plant comprises that one or more has the endless tube (2) of built-in agitator (3,20,21), agitator provides by the turbulent flow of endless tube and piston flow, and the liquid that has purified then separates at flotation unit or in settler with pollutent.

2. the device of decontaminating liquid, wherein liquid is polluted by other liquid or solid material, for example deoiled from removing the water of oil pollution, comprise flocculation plant and flotation unit (8), it is characterized in that described device comprises the endless tube (2) that has built-in agitator (3,20,21) that links to each other with flotation unit (8).

3. according to the device of claim 2, it is characterized in that endless tube is made up of the vertical tube parts (2) that link to each other with horizontal pipeline section, every duct member has agitator, agitator comprises the axle (20) that is driven by drive unit (3,18), described axle supporting water screw parts etc. also pass this parts, and agitator also comprises static guide vane.

4. according to the device of claim 3, it is characterized in that one or more duct member all has the connection line (4) in order to add one or more chemical.

5. according to the device of claim 3-4, it is characterized in that at least one duct member is equipped with in order to supply with the connection line (4) of flotation gas.

6. according to the device of claim 2-5, it is characterized in that bubbling producer (5) places between endless tube (2) and the flotation unit (8).

7. according to the device of claim 2-5, it is characterized in that bubbling producer (5) places exterior tube system (14), wherein an end of this system links to each other with flotation unit (8), and the other end links to each other with lucky endless tube (2) in the flotation unit front.

8. according to the device of claim 6-7, it is characterized in that the bubbling producer is made up of static mixer (5).

9. according to the device of claim 6-8, it is characterized in that between flotation unit (8) and bubbling producer, scatterer being set.

10. according to the device of claim 2-9, it is characterized in that flotation unit has coalescer (9).

11., it is characterized in that the plate (lamella) that coalescer (9) comprises level or is obliquely installed according to the device of claim 10.

12., it is characterized in that described plate is corrugated or is the form that helps to form at their downsides air bag (gas pocket) according to the device of claim 11.

13., it is characterized in that plate scribbles oil-resisting PTEE coating etc. according to the device of claim 12.