NO164077B - PROCEDURE FOR THE TREATMENT OF SOLID MATERIAL FOR THE REMOVAL OF EVAPORABLE MATERIALS THEREOF. - Google Patents

Description

The invention relates to a method for treating solid material to remove vaporizable substances from it, including a thermal separation process where the solid material is subjected to heating and steam distillation for the evaporation of substances to be separated from the material, in particular for the removal of hydrocarones from drilling cuttings, contaminated soil etc., as the heating for evaporation includes heating in a heat exchanger, which includes a housing with a rotatable hollow rotor arranged therein and where the material is transported under indirect heating from an inlet and to an outlet, which heating is carried out with a rising temperature profile in the direction of transport, since the exhaust gas is taken out from the heat exchanger and led to a condenser.

As examples of materials that the method has been developed to treat, drilling mud waste can be mentioned in general - especially in connection with the use of oil-based drilling mud. Such waste is excreted during drilling and when reducing the weight of mud after drilling is finished. The waste consists of the formation minerals drilled out of the well, as well as oil, water, barite, fine particulate clay and various additive chemicals). In the case of weight reduction, the waste consists of a proportionally larger amount of barryte, or another weight material.

The ratio between solid and liquid in the waste will vary greatly depending on the geological conditions where the well is drilled, as well as according to the installation's/drilling vessel's mud processing equipment.

Experienced liquid content is between 15 and 60# on a weight basis.

Water-based sludge, where special chemicals (polymers etc.) are used, is naturally also a material that the method can be used to treat. Such sludge does not contain "drilling oil", i.e. ordinary paraffins, but is otherwise much the same with respect to the waste.

Another material group of interest is contaminated sand, soil, seaweed etc. in connection with shipwrecks and oil/chemical potassium spills.

The procedure can also be used for the treatment of oil and chemically contaminated soil/sand in connection with landfills/fill sites, leakage from oil pipelines and other process pipelines, accidents at transport/tank facilities etc.

In connection with the treatment of solid material to remove volatile substances from there, there is a clear need to be able to separate the volatile substances in such a way that they are not destroyed or decomposed. The sale/reuse of the substances could be decisive for the economy in a process where solid material is treated for the removal of evaporable substances. There is therefore a clear need to be able to carry out the thermal separation process at temperatures as low as possible, because many of the substances in question will be destroyed or decomposed under the influence of the temperatures that are usually used to cause the substances to evaporate.

The invention is based on the utilization of the known water vapor distillation effect. As is known, steam distillation enables the evaporation of substances at a reduced evaporation temperature.

From US-PS 4,139,462 it is known to utilize the water vapor distillation effect with regard to the heavier hydrocarbon fractions in oil, but the effect is only linked to the water present in the raw material, i.e. the drilling cuttings, and is therefore conditioned by the composition of the raw material before treatment. The co-driving effect is achieved by the water being converted into super-heated steam.

According to the invention, a method is therefore proposed as mentioned in the introduction, which method is characterized by water vapor being injected directly into the material in a lower temperature range in the heat exchanger, and this water vapor injection is preferably carried out in an area of between 20 and 50# of the heat exchanger's transport length.

As an example of heat exchangers that can be used according to the invention, reference should be made to NO-PS 95490 and NO-PS 122.742, which show and describe respectively a conventional steam dryer and a heat exchanger for indirect heating, drying or cooling of more or less moist solids or semi-solids materials.

With such a method according to the invention, a gentle heating profile is achieved for the material in the heat exchanger. The water vapor distillation effect is improved by the heating being carried out with a gradually rising temperature profile in the direction of transport, with the injection of water vapor into the material in a lower temperature range.

In particular, the invention achieves a deliberate reproduction and control of the steam distillation, independent of the composition of the raw material (especially water content), but conditional on the molecular weight/structure of the hydrocarbon compounds present. A super-heating of water vapor is avoided or greatly reduced by increasing the relative water content in the heat exchanger with the injection of water vapor, with associated more favorable energy consumption. At the same time, the total temperature of the gas mixture is reduced, which is beneficial both with regard to specific heat and the targeted gentle treatment (recycling value of the oils).

From the widely available Norwegian patent application no. 771423, it is known to use a form of steam distillation using superheated steam. Such use of superheated steam is deliberately avoided according to the present invention, in order to save energy. No oxidizing atmosphere is used either. The gases mentioned in the aforementioned patent application will have a disruptive effect and will reduce the operational stability and capacity of the process.

From US-PS 4,319,410 a process is known which works under vacuum. No steam distillation is used. A clear difference is also that, according to the present invention, one preferably works at atmospheric pressure, as this provides a far more affordable design.

From US-PS 4,209,381, the use of direct heating by means of steam that is sprayed on drilling waste is known. It does not involve any injection into the drilling waste to control or reproduce the water vapor distillation effect.

From US-PS 4,222,988 it is known to use a combined heating and crushing and the whole thing is kept under vacuum. No steam distillation is described there.

The water vapor injection has several significant advantages.

Closely related to the reproduction/management of water vapor desolation effect is the achievement of increased drift of hydrocarbons

- especially heavier hydrocarbons and compounds, i.e. better degree of separation/purity. The specific heat transfer rate in the heat exchanger will be increased. The raw material capacity for a given heating surface will therefore increase considerably without reducing the separation efficiency and product quality. This increase is due to

greater (longer) absolute contact time between hot surface and

a lot,

better convection properties,

greater degree of replacement of fluid around the individuals

solid particles that thereby increase heat exchange, coatings that form during the transition from wet to dry phase and

prevents heat transfer, is torn up by the steam, improved flow and transport properties of the raw material

(lumps dissolve, air pockets collapse, etc.),

the direct water vapor injection in itself provides an improved agitation of the raw material.

At a given hot surface/solid temperature, there will be varying water vapor content, different "equilibrium temperatures" are formed in the total gas mixture. This will provide more gentle separation (increased distance from the cracking area of the oils or oil compounds), as well as a reduction of any unfavorable overheating of the raw material's solid particles. This will overall give better end product quality.

The relative heat loss to the surroundings is reduced due to lower temperature difference between steam and ambient temperature.

A material filling of between 60 and 90$ of the volume of the heat exchanger during the heating in the heat exchanger has proven beneficial. Before heating, it may also be advantageous to crush the material. Especially when sorting out and mechanically crushing large particles, it will be possible to achieve an improved separation of raw material with large particles and strongly capillary bound oil.

If necessary, the material can be conditioned (heated) before introduction into the heat exchanger, and advantageously such conditioning can include the supply of hot water to the material. This controlled mixing of water into the material gives better "flow" properties and a certain control of the water drive effect.

Usually the treatment in the heat exchanger will take place under atmospheric pressure or a slight overpressure, but in some cases the evaporable substances may be of such a sensitive nature that it may be expedient to work under negative pressure in the heat exchanger.

According to the invention, the method can advantageously be carried out with compression of the exhaust gas from the heat exchanger, before the exhaust steam goes to the condenser. Particularly advantageous in this connection, compressed exhaust gas can be led to an evaporator for indirect exchange to produce low-pressure steam that is used as injected water vapor and/or as a heating medium for the indirect heating in the heat exchanger.

According to the invention, the condenser can advantageously be used for heating conditioning water and/or feed water for the production of steam for injection and/or hot water for the indirect heating in the heat exchanger.

According to the invention, the treated material can advantageously be supplied with water in an outlet sluice after the outlet from the heat exchanger. This will not only provide a cooling of the treated material, but will also provide superheated water vapor which will form a dynamic overpressure and drive in countercurrent to the outgoing material and into the heat exchanger and out via the present exhaust system. This will prevent evaporated oil

to follow out into the outlet and condense/leak out on/with the treated material. It is assumed that it will also be possible to achieve a certain hydrodynamic effect with respect to residual hydrocarbons in the material.

Supply of water beyond what evaporates will bind the dust in the material. Water-moistened, treated material will also be able to provide better sealing/flow properties with regard to the formation of a desired material plug in the lock.

Part of the treated material can be fed back from the heat exchanger's outlet for mixing with material to be treated. Such back-dosing will be particularly advantageous when the material to be treated is of a particularly moist/sticky nature. Such material requires that unwanted coating formation in the first part of the heat exchanger must be broken up in order to maintain efficiency. The back dosing contributes to this because the mixing of the dry material with the raw material will change the physical properties of the material.

As a heat exchanger, as mentioned, one of the known continuous dryers can advantageously be used which includes a housing with a rotatable, hollow shaft or rotor with the supply of a heat carrier and removal of the same or a condensate thereof, where the rotor carries hollow rotor plates, see the in front of the aforementioned N0 patent documents.

The invention shall be described in more detail with reference to the drawings, where: Fig. 1 shows a flow chart for an overall process where

the method according to the invention can include, fig. 2 shows a diagram showing residual oil in particles after indirect heating with hot oil, as a function of particle diameter, as well as residual oil in particles with direct heating contribution, and steam distillation in addition (from steam injection),

fig. 3 shows a diagram where the boiling point is listed as a function of weight percent water in a mixture of

water and oil,

fig. 4 shows a diagram with the temperature profile obtained by combined heating (preheating from the heat recovery, steam injection and hot oil heating) as well as less favorable temperature profile

by hot oil heating alone,

fig. 5 shows a flowchart for a method according to

the invention,

fig. 6 shows a flow chart for a variant of the process

in fig. 5, and

fig. 7-10 show flowcharts for different variants of processes where the method according to the invention is used.

The block diagram in fig. 1 shows an overall process in which the method according to the invention is included. Depending on the type of raw material, all or some of those in the block diagram in fig. 1 shown functions are used. Common to all types of raw material and thus central to the process is the implementation of a thermal separation, which can be carried out directly or according to those in fig. 1 showed initial treatment or pre-processing. For example, drilling mud waste can normally be homogenised/conditioned directly and fed to thermal separation. The only pre-treatment that may be relevant in this connection is classification with regard to coarse/fine particles and crushing/grinding of the coarse particles before the submasses are mixed (homogenized) and fed to thermal separation.

Treatment of other raw materials is usually started with rough sorting, where any scrap, i.e. wood, large stones, lumps of concrete and steel/iron are removed before classification. This can be done manually or with the help of a magnet and coarse sieves. After this sorting out of foreign elements, the raw material 1 is classified according to type, particle size/distribution, contaminants and need for further treatment - for example using vibrating sieves with varying cloths etc.

For raw material with strongly bound capillary oil, it will be advantageous or necessary to have some crushing of coarse particles in order to achieve satisfactory results.

In a normal process, the raw material will either undergo washing or extraction, or be fed directly to the thermal processor's feed tank, where homogenisation and conditioning using agitators, hot water injection and indirect heating can be carried out before feeding to the processor (heat exchanger).

The conditioning, which can for example be done using hot water and/or indirect heating, is usually carried out to achieve better "flow" properties, but a direct supply of hot water will also contribute to increased water operation in the processor (and thereby also reduce the need for steam injection into the processor). In connection with the reception/treatment of frozen raw material that is to be thermally separated directly, the heating will be particularly important.

Washing with water and/or extraction is mainly carried out on raw materials that contain water-soluble chemicals, as oil-soluble ones will follow the oil phase from the thermal processor and the oil is easily separated afterwards. The washing liquid is treated conventionally by means of precipitation, flocculation, filtration and the like after washing out, and the respective chemicals can then be destroyed or used in their respective relevant quantities.

After washing/extraction, if special conditions warrant this, the raw material can be returned to classification and possibly undergo complete or partial grinding down of large particles before delivery for homogenization/conditioning and further feeding to thermal separation.

After satisfactory/selected homogenization and conditioning, the raw material is fed to a rotating heat exchanger known from other applications, where mainly indirect heating of the raw material with subsequent evaporation of contained liquid takes place.

Depending on the raw material, specific liquid ratio/content, specific capacity and the degree of capillary/adhesion-bound oil, the required separation temperature of the raw material will vary from just over 100°C to just under 300°C. This temperature range is achieved by indirect heating, mainly by the heat exchanger's rotor ( in some cases it will also be beneficial to supply heat in the stator).The heat-carrying medium usually used for material temperatures above 100°C to 180°C is saturated steam and for material temperatures above 180°C to 300°C hot oil is used (hot oil can, if desired , used over the entire temperature range).

Normally, the heat exchanger or processor is operated under slight atmospheric overpressure (5-40 millibars) to avoid any possible penetration of oxygen (air) and to achieve self-drive on exhaust gas. In some cases, however, it will make sense to operate under negative pressure to further promote evaporation (lower the boiling point curve for the mixture) or more gentle separation as the substance temperature can thereby be lowered. The lowest operating pressure for the heat exchanger will normally be 0.1 bar absolute. In this range (0.1 - 1.1 bar a), only simple measures in the form of changed material locks on the inlet and outlet, and a vacuum pump/liquid lock after the condenser in the desired operating pressure range, will be necessary.

The exhaust gases (i.e. mainly water and oil) are led from the thermal processor to indirect condensation and sub-cooling, and subsequent precipitation/separation. Non-condensable substances that pass the condenser (for example split chemical substances from drilling mud, and to some extent cracked hydrocarbons) are led to a hot oil or steam boiler where complete combustion and conversion of the gas's energy takes place. This combustion destruction can be functionally combined with the boiler's main burner in one and the same function. Alternatively, the gases are led to absorption in an activated charcoal filter.

After conventional separation, further treatment of the liquid phases can be carried out, e.g. in connection with cleaning equipment in connection with the washing process.

Water discharge from the process will contain a maximum of 30 ppm hydrocarbons/compounds as an upper limit.

Outgoing dry matter from the processor can be directed with the help of compressed air to a conventional bulk silo. The silo can be double-walled for cooling/heat recovery from the dry matter. In the event that the dry matter, from contaminated soil, is suitable for return as usable soil, this culturing can be carried out in connection with the processing plant.

The outgoing dry matter from the processor will normally contain less than 1 wt-5É of hydrocarbon residues.

Biological finishing - as part of a complete plant - will be able to be carried out, to produce a ready-made/composed product which, after a certain maturation period after deposition/deployment, will be usable as full-fledged soil.

Crushing and grinding of pulp can be carried out after washing/extraction processes or directly for pulp that is not washed/extracted. The purpose of such crushing/grinding is as follows, with reference to fig. 2. Particles that have been exposed to oil under high pressure (e.g. reservoir conditions) will have a relatively large degree of oil filling in the pores. Removal of oil from these particles will decrease inwards towards the core, because heat transfer is poor and the oil's transport path out of the particles is long. Residual oil in particles as a function of particle size is qualitatively shown in fig. 2. The solid line shows residual oil in particles by indirect heating with hot oil, as a function of particle diameter. Corresponding curve with direct heating contribution (from water vapor injection) is shown with the dashed curve.

Crushing/grinding is recommended for coarse drilling mud waste, but is considered less necessary for oily soil and the like. As mentioned, the utilization of the steam distillation effect (water drive effect) is central to the present invention. Injection of water vapor as well as water already present causes the boiling point temperature of the system as a whole (oil + water) to be lower. This is schematically shown in fig. 3.

That in fig. The boiling point progression shown in 3 results from the fact that accumulations of water molecules that are driven by (from 100"C upwards) will drag oil molecules with them due to the attractive forces that act between the water molecules and the oil molecules (Van der Waal binding forces).

The use of the steam distillation principle in this context is two-sided. The utilization ensures gentle processing (moderate temperatures) with limited destruction of the raw material and also provides better heat transfer properties.

The most important advantages of direct water vapor injection can be summarized as follows: Increased water quantity results in increased oil removal from each particle due to increased washout effect and reproduction of the washout in the heat exchanger. Better heat transfer properties due to increased liquid content and contribution from direct heat transfer from condensing steam. Hot water/steam will more easily displace capillary-bound and surface-bound oil from the mass.

Increased liquid content gives increased miscibility in the mass and provides better distribution of transferred heat in the total mass.

It should be mentioned here that when processing at maximum temperatures of between 180°C and 300°C, the risk of so-called cracking will be small, but small amounts of light hydrocarones can be formed. However, these can be destroyed in the combustion chamber of a hot oil loop or a steam loop in the plant.

Possible implementations of the method according to the invention will now be described in more detail with special reference to fig. 5-11, which show different process solutions for the method according to the invention.

As mentioned, thermal separation is a central point according to the invention. From the previous pre-processing, two factors will have a specific meaning for the thermal part:

a) possible particle size reduction (crushing)

b) water content (from washing and/or conditioning).

These factors will have a direct impact on the thermal process part's treatment performance, i.e. with regard to direct steam injection quantity, residence time, heating profile and to some extent separation efficiency/operating temperature.

The overall parameters for the thermal process part are: continuous processing,

stable capacity (regardless of raw material type),

stable, efficient separation (for example less than 1$ hydrocarbons in dry matter),

high reuse value of the separation products (gentle treatment).

This is achieved to a large extent directly in the used heat exchanger (processor) as a result of its, for the purpose particularly favorable constructive design, as well as by direct application and control of the water vapor distillation effect, and the possible, particularly favorable heating profiles in the first part of the processor.

In fig. 5 shows a processor 1. This is a heat exchanger which has a housing 2 with a rotor 3 arranged therein. The rotor 3 mainly consists of a hollow rotor shaft 4 on which a number of hollow rotor discs 5 sit. The cavities in the rotor discs 5 are open to the cavity in the rotor shaft 4. On the rotor discs 5 there are not shown vanes or the like which effect a material transport through the heat exchanger, in the direction from left to right in the drawing figure. The processor 1 has an inlet 6 and an outlet 7. There is also an exhaust gas outlet 8 from the housing 2.

The inlet 6 is supplied with the material to be treated from a conditioning tank 9. The exhaust gas outlet 8 is connected through a line 10 to an indirect condenser 11. The outlet 7 is connected with a shaft 12 to an outlet sluice 13. The hollow rotor shaft 4 is supplied with steam from a boiler 14 through a wire 15.

The conventional heat exchanger described so far has been modified in that it is fitted with a water vapor injection device 16. This can have many practical embodiments, which will be obvious to a person skilled in the art. For example, it could be several nozzle openings taken out in the casing 2 of the house and connected to a common, welded-on manifold, so that water vapor can be injected directly into the material that is in the dryer. Here, the steam supply takes place through a line 17 from the line 15 from the boiler 14.

The material to be processed is delivered, as shown by the arrow 18, to a sorter 19. Coarse material goes to a crusher 20 and from there to the feeding and conditioning tank 9. As shown, fine material goes directly to the tank 9. The tank 9 is fed, if necessary, here also dry matter from the outlet shaft 12 through a line 21. From the feed and conditioning tank, the conditioned material goes to the heat exchanger's intake 6, as shown by arrow 22.

Hot water for conditioning is supplied to the material in the tank 9 through a line 23 from the condenser 11, whose cooling water supply is shown at 24.

The exhaust gas formed during processing in the processor 1 goes out through the exhaust gas outlet 8 and to the condenser 11 through line 10. Condensate goes out through line 25.

The treated material, here also called dry matter, is taken out in the outlet 7 and passes through the shaft 12 to the outlet lock 13. A transport screw 26 in the lock 13 brings the dry matter to a discharge zone 27. In a water supply zone 28, water is supplied from the condenser 11 through the line 23 and a branch line 31. The water supply will here result in the formation of water vapor which will give a dynamic overpressure and drive in countercurrent to the dry matter and back to the processor 1, as shown by the dashed arrow 29. This will prevent evaporated oil from following the dry matter out the overflow 30 in the heat exchanger and condense on or leak out with the dry matter. It will also be possible to achieve a certain water driving effect with regard to hydrocarbons in the dry matter.

Supply of water in excess of what is evaporated will bind dust in the dry matter, as well as increase or provide moisture which causes a certain "lubricating" effect in the transport screw 26. The binding of dust will greatly simplify further transport of the finished product.

The water supply in the lock also cools the product.

A material "plug" is desirable in the lock. The formation and control of such a plug, in the discharge zone 27, is facilitated when the dry material is moistened with water, because the material will have better sealing/flow properties.

It has not been tested, but it is believed to be possible to return all condensed and separated process water to the finished product and thereby meet all requirements for discharge water.

The plant in fig. 6 essentially corresponds to the plant in fig. 5. The process plant has been modified in relation to that in fig. 5, whereby a hot oil boiler 32 is used for the heating in the processor 1, and for steam production in a steam generator 33. The sluice 13 and the generator 33 are supplied with water from the condenser 11 through the lines 34,35. The generator 33 supplies steam to the injection device 16 through a line 36. For the plant components found in fig. 5, the same reference numbers are used.

The facilities in fig. 5 works with an operating temperature of up to 180°C, with saturated steam as indirect heating medium. The steam temperature in line 15 is between 120°C and 180°C at a pressure of from 2 to 10 bar g.

Corresponding operating conditions exist in the plant shown in fig. 7. In principle, this facility is built in the same way as the facility in fig. 5, but the hollow rotor 4 is divided here, in that it is provided with an internal dividing wall 37. Such a two-part rotor design contributes to a very gentle heating profile and heat recovery. In this connection, it should be mentioned here that the stator, i.e. the housing 2, can also be designed as a heat-transferring surface, and the stator can therefore also be divided in the same way as the rotor.

Hot water from the condenser 11 is fed in fig. 7 through a line 38 towards the rotor's (and possibly the stator's) dividing point, i.e. the wall 37, and then flows countercurrently towards the incoming raw material and out through the line 39. The indirect condenser 11 is operated so that the outgoing hot water will maintain the highest possible temperature (before inflow into the processor 1) without exhaust gases passing the condenser (apart from non-condensable substances). From line 39, a line 41 branches off to tank 9.

Steam is supplied from the steam boiler 14 through the line 15 to the rotor 4 and to the steam injection device 40, which is here moved in relation to the location in fig. 5 and 6, so that the water vapor injection into the mass in the processor 1 first begins approximately at the dividing point 37. In the hollow rotor shaft 4, the steam will go towards the dividing wall 37 and back, on the other side of a longitudinal dividing wall in the hollow rotor 4, and back to the steam boiler. Otherwise - it is for plant components that can be found in fig. 5 and 6 used the same reference number.

The two-part Indirect heating (two-part rotor and possibly stator) will, combined with the direct heating contribution from injected steam in the transition between the two indirect heating furnaces, provide a gentle (stepwise) heating of the material in the heat exchanger.

The plant 1 fig. 8 has sorter 19, crusher 20, feed and conditioning tank 9, and condenser 11 as well as outlet sluice 13 as in fig. 5-7, but the processor (heat exchanger) 1 is of the modified type as shown in fig. 7, i.e. with split rotor (wall 37). As in fig. 6, a heating oil boiler 32 is used with a connected steam generator 33, but here the heating oil goes through a line 42 to the right side of the partition wall 37, while the left part of the rotor 4 is connected to the condenser through a line 43.

Steam to the one in fig. 7 placed injection device, goes through a line 44 from the steam generator 33. The heating water used in the rotor 4 goes to the tank 9, the lock 13 and the generator 33 through the lines 45, 46 and 47 shown.

The plant in fig. 9 has, like the plants described above, a sorter 19, a crusher 20, a feeding and conditioning tank 9, a condenser 11 and a sluice 13. The processor 1 is of the one in fig. 7 and 8, split type (partition wall 37 in the rotor 4), and a steam boiler 14 is used, as in fig. 5 and 7.

In the plant in fig. 9, the exhaust gas, which goes from the processor 1 through the exhaust outlet 8, is compressed in a compressor 48. The compressed exhaust gas goes to an evaporator 49. From there it goes through the line 50 to the condenser 11. The condenser is used in this case to subcool the condensate from the evaporator. Cooling water from the condenser 11 goes through the lines 51,52 to the evaporator, and goes to the tank 9 and the lock 13 through the lines 53 and 54.

Low-pressure steam formed in the evaporator 49 passes through a line 55 to the left part of the split rotor 4 for heating this rotor part, and returns through the line 56. The low-pressure steam is also used as an injection medium in the steam injection device 40 (through the line branch 57). The facility 1 fig.10 differs from the facility in fig. 9 only in that the steam boiler 14 has been replaced by a hot oil boiler 58, and the right rotor part is therefore heated with hot oil, through the lines 59,60.

The hot oil temperature will be in the range 180-320<*>C. While the maximum process temperature goes up to 180<*>C in the plants with a steam boiler, the maximum process temperature goes up to approx. 300'C in the facilities with hot oil boilers.

Those in fig. The facilities shown in 9 and 10 have been developed for optimal energy utilization.

Although they in fig. The solutions shown in 9 and 10 represent solutions that require a certain increase in the investment costs beyond the basis necessary for carrying out the method according to the invention, one will achieve a not insignificant energy economic gain (estimated 50-70$ in relation to the more conventional solution in Fig. 5 and 6). Those in fig. Optimal solutions shown in 9 and 10 introduce the use of a compressor, where exhaust gas from the gas outlet (the exhaust gas usually has atmospheric pressure) is compressed up to a maximum of 2 bar absolute. Further compression will not be cost-effective, nor favorable with respect to the exhaust gas's reuse quality as condensate (the oil phase). This weak compression is used primarily to raise the condensation temperature point for the water content of the exhaust gas (where the largest amount of energy is "stored") so that this can be exchanged at a higher "level" for: water to steam. This will provide a heating medium that can be exchanged for the first part of the rotor (to the left of the dividing wall, possibly a corresponding amount on the first part of the stator) and which contains more energy at a higher "level" and thereby in turn adds more heat to the incoming raw material for the benefit of the steam or hot oil boiler's heat supply. The favorable heating profile (to be explained in more detail below) and the use of steam injection will be as described above. When saturated steam is generated as an alternating medium in the evaporator, injection steam for the process itself will also be taken from this - somewhat conditional on the nozzle arrangement in the steam injection device and raw material type - in favor of the steam boiler/steam generator in the respective proposed solutions. The overall utilization of generated steam from the evaporator to the first part of the rotor (possibly the stator) and direct injection thus gives an energy gain of 50-70$ over the more conventional solution.

The most energy-optimal solution is therefore with compression of exhaust gas and indirect switching to water which is converted into saturated steam, especially justified on the basis of the fact that this steam is used both for indirect heating in the first part of the rotor (stator), possibly in the conditioning tank before the processor as well as for direct injection (reproduction/management of the water operation). The energy course then describes an almost closed circuit (if one looks away from the losses) and both process-result/energy consumption are optimal, at the same time that the injection amount can be varied/increased over a much larger area and only determined on the basis of the raw material's /the needs of the separation process.

When carrying out the new method, water vapor of 115 to 180°C is injected into the heat exchanger by means of the water vapor injection device. The longitudinal section of the heat exchanger that is covered by the injection device is, for example, 30% of the length of the heat exchanger and is divided into sections by means of valves that control the supplied quantity in each section. Such sectioning for the steam injection can be relevant both for the processor's longitudinal and transverse profile. The distribution of the injection amounts between the sections is adapted so that a temperature profile with a moderate gradient of rise in the longitudinal direction is achieved.

Too rapid temperature increases will drive out the water before the specific effects of the water have been utilized.

High temperatures at an early stage in the heat exchanger will also cause a disproportionate amount of energy loss to superheat the steam in the heat exchanger.

A desired temperature profile is schematically shown in fig. 4. This figure shows a solid line representing the temperature profile for combined heating (preheating, steam injection and hot oil steam heating). The dashed line is the temperature profile for conventional heating, see fig. 5 and 6.

The particular choice of processor (heat exchanger) will be linked to the following effects:

- Large hot surface on the rotor,

good opportunity for different heating media in different parts of

the rotor,

- good mixing in the mass, as this improves heat transfer, controlled degree of filling.

Of the available volume in such a heat exchanger, a favorable degree of filling will be 60-90$ for the mass. The remaining volume is disposed of by evaporated oil and water, which goes to the exhaust gas outlet, which will be beneficial for the drift.

In a rotating heat exchanger, with a uniform direction of rotation, the material will continuously "overturn" and form a crash surface in the cross section. This means that the material has an uneven distribution in the cross section. To compensate for this, one can therefore advantageously control the water vapor injector over a cross-sectional section. In the schematic drawings, a row of nozzles is shown in the longitudinal direction of the heat exchanger. Correspondingly, nozzles can be arranged next to each other in the transverse direction (normally on the drawing plane). A nozzle pattern is therefore used with nozzles placed in lines and rows. With such, or a similar nozzle pattern, the injection can be controlled both in the width section as well as in the length section of the heat exchanger. The steering in the longitudinal section can be beneficial to compensate for that. condition that in the beginning phase the water content will be relatively large, while it will gradually decrease. Therefore, it may be necessary to supplement with water, supplied with the steam injection. The injection profile controlled in this way is determined based on the operating conditions.

Claims (12)

1. Procedure for treating solid material for the removal of vaporizable substances from it, including a thermal separation process where the solid material is subjected to heating and steam distillation for vaporization of substances to be separated from the material, in particular for the removal of hydrocarones from drill cuttings, contaminated soil, etc. as the heating for evaporation includes heating in a heat exchanger, which includes a housing with a rotatable hollow rotor arranged therein and where the material is transported under indirect heating from an intake and to an outlet, which heating is carried out with a rising temperature profile in the direction of transport, as the exhaust gas is taken out from the heat exchanger and taken to a condenser, characterized in that water vapor is injected directly into the material in a lower temperature range in the heat exchanger, and this water vapor injection is preferably carried out in an area of between 20 and 50$ of the heat exchanger's transport length. 2. Method according to claim 1 or 2, characterized in that the heating in the heat exchanger is carried out with a material filling of between 60 and 90$ of the volume of the heat exchanger. 3. Method according to one of the preceding claims, characterized in that the material is crushed before heating. 4. Method according to one of the preceding claims, characterized in that the material is conditioned (temperature and water content) before introduction into the heat exchanger. 5. Method according to claim 4, characterized in that the conditioning includes supplying hot water to the material. 6. Method according to one of the preceding claims, characterized in that the material is kept under negative pressure in the heat exchanger. 7. Method according to one of the preceding claims, characterized in that the exhaust gas from the heat exchanger is compressed and led to a condenser. 8. Method according to claim 7, characterized in that compressed exhaust gas is led to an evaporator for indirect exchange to produce low-pressure steam which is used as injected water vapor and/or as a heating medium for the indirect heating in the heat exchanger. 9. Method according to one of the preceding claims, characterized in that the condenser is used for heating conditioning water and/or feed water for the production of steam for injection and/or hot water for the indirect heating in the heat exchanger. 10. Method according to one of the preceding claims, characterized in that the treated material is supplied with water in an outlet sluice after withdrawal from the heat exchanger. 11. Method according to one of the preceding claims, characterized in that part of the treated material from the outlet on the heat exchanger is fed back for mixing with material to be treated. 12. Method according to one of the preceding claims, characterized in that the water vapor injection is varied in the longitudinal and transverse sections of the heat exchanger, to achieve a controlled injection profile.