Process and Apparatus to Separate Oil from Mineral Matter

Abstract

A process for the separation of hydrocarbons from oil-containing solids comprises heating the oil-containing solids in one or several in-series operated continuous mixers by addition of hot solids to the oil-containing solids, thereby forming a mixed solids phase, wherein heating is conducted at a temperature at which most of a hydrocarbon fraction in the oil-containing solids is transferred into a gas phase in the mixer(s), wherein the mixer(s) are positioned horizontally or slightly inclined in a conveying direction and wherein the mixer gas phase is cooled simultaneously to a temperature below 400° C. before or upon exiting the mixer(s). A mixer for the process comprises a continuous mixer having at least one horizontal or in flow direction slightly sloped shaft, fitted with wear resistant stifling devices.

Description

The present invention pertains to a process and an apparatus for the separation of oil from mineral matter by heat treatment. Oil and mineral matter are often combined with one another, e.g. in the case of waste materials. Economically important is the production of hydrocarbons out of oil sands and oil shale, which are found in nature. Oil shale contains oil only as a precursor. Oil must be created by heat treatment, as is also the case for other feedstocks like wood or harvest residues. The production of oil products from such organic matter is subject matter of the invention as well.

THE RELEVANT TECHNOLOGY

Oil can be separated from mineral matter, especially some oil sands, by treatment with hot water and surfactants like caustic soda (en.wikipedia.org/wiki/oil tars). Related processes are known in environmental technology when washing contaminated soils.

Oil, which is adhering in-situ to minerals, can be liquefied by steam thereby making it pumpable. Both processes were developed in commercial scale in Canada (en.wikipedia.org/wiki/oil tars). Yield is limited and the processes require huge amounts of external energy. Production wastes containing oil form a burden to the environment.

Out of many oil containing solids oil can hardly be separated in this way. This is particularly valid for oil shale (en.wikipedia.org/wiki/oil shale), where the oil must first be created by heat treatment of precursory compounds. Numerous high temperature processes were developed for this.

Thermal in situ processes are being tested. At the Shell Mahagony Project e.g. the oil shale is heated electrically. The oil, which is created should flow to a well. (U.S. Pat. No. 6,729,401A, U.S. Pat. No. 6,688,387A, U.S. Pat. No. 6,729,397A, U.S. Pat. No. 6,758,268A, U.S. Pat. No. 6,769,483A, U.S. Pat. No. 6,789,625A, U.S. Pat. No. 6,591,906A, U.S. Pat. No. 6,719,047A, U.S. Pat. No. 6,745,837A, U.S. Pat. No. 6,581,684A).

The disadvantage of in situ processes is, that heating occurs slowly. For oil shale as well as wood maximum oil yield can only be achieved by a short time pyrolysis, which on one hand minimizes the formation of residues with high carbon content, on the other the production of gas. In situ processes also create toxic aromatic compounds, which partly remain in the soil. These are e.g. phenols, which may contaminate ground water.

Ex situ processes exhibit the same problems, when the feedstock is heated, but not totally pyrolysed or burned (Jyri Soone et al.: Environmentally sustainable use of energy and chemical potential of oil shale, International Oil Shale Conference 7-9 Nov. 2006 Amman, Jordan).

Ex situ processes mostly use vertical kilns (GB211033A, GB711366A, GB710377A, GB217174A, U.S. Pat. No. 3,960,702A, U.S. Pat. No. 4,944,867A, U.S. Pat. No. 5,041,210A), also fluidized beds (U.S. Pat. No. 4,495,059A) or rotary drums (GB202107A, WO 2004/007641A1).

Most processes have in common, that they avoid oil oxidation. The required heat is fed to the oil containing solid by indirect transfer (GB202107A), by a hot gas (U.S. Pat. No. 4,297,201A, WO2004/007641A1, U.S. Pat. No. 3,960,702A, U.S. Pat. No. 5,041,210A, U.S. Pat. No. 4,944,867A, GB217174A) or by mixing with hot solids, mostly combustion ash of the same process (U.S. Pat. No. 4,619,738A). The combination of feeding a hot solid for heating and of non oxidizing strip gas is mentioned too (U.S. Pat. No. 4,495,059A).

The mineral part of oil shale often consists of carbonates. Their decomposition has to be avoided because of thermodynamic reasons, mostly however to minimize carbon dioxide emissions. (UCRL-CONF-219767. Comparison of the Acceptability of Various Oil Shale Processes. Alan K. Burnham, James R. McConaghy. Mar. 14, 2006).

In the following, thermal processes shall be discussed in more detail which have been used during the last 30 years in technical or commercial scale for the separation of oil from mineral matter.

Thermal treatment of oil contaminated soils or oil industry production residues is in the most advanced status. Heat is mostly transferred in directly heated rotary kilns. (www.atmmoerdijk.nl/sha/contentmgrnl.nsf/frameset?openform&atm). The oil phase is burned in the process. There are however other processes, where the heat is transferred indirectly and most of the oil is not decomposed in the rotary kiln. (www.sitaremediation.de/thermische-anlage-herne.html).

To treat oil shale in Australia the ATP rotary kiln process was used (U.S. Pat. No. 4,306,961A). It belongs to the categories indirect heat transfer and mixing in of hot solids. In the first stage oil shale is indirectly heated to 250° C. Water vapour, which is produced, is extracted from the drum. Then the oil shale is spontaneously heated in a pyrolysis chamber to about 500° C. Oil vapours and crack gas are discharged by a pipe. The pyrolysis coke, which is contained in the mineral residue, is combusted in the next zone. The ash is partly sent back to the pyrolysis chamber, where it causes the intensive heating. The rest of the ash gets to the preheating zone and heats up the input shale by indirect heat transfer. The whole process is proceeding in a single rotary kiln, where in counter current flow the feedstock takes up the heat from the ash, which is heated to about 750° C.

The rotary kiln for the ATP process has a very complicated design and suffers under problems like thermal stress, wear and the build up of mineral residues. Its capacity is limited by the indirect heat transfer between feedstock and combustion residue/flue gas.

In Brazil heat is transferred to oil shale by a hot non oxidizing gas in the Petrosix process. This is related to the Estonian Kiveter process (Jialin Qian, Jianqiu Wang: World oil shale retorting technologies; International Oil Shale Conference 7-9 Nov. 2006 Amman, Jordan).

Both processes require for the heating up great volumina of gas in relation to the solids, which results into the use of huge blowers and other apparatus. To make hot gas flow through the oil shale bed, minimum particle sizes must be limited to about 20 mm. Part of the oil shale is combusted for the heating up and so its oil content cannot be recovered. Additionally the separation of low boiling hydrocarbons from the gas is difficult. The produced solids still contain a high percentage of environmentally hazardous organic compounds, especially phenols.

Processes, which for preheating bring flue gas in direct contact with oil containing solids, may produce an off-gas, which contain hydrocarbons. The Galoter process belongs to those (Jialin Qian, Jianqiu Wang: World oil shale retorting technologies; International Oil Shale Conference 7-9 Nov. 2006 Amman, Jordan). After a drying step using hot flue gas the oil shale is heated up by blending in hot ash. This makes it belong to the processes, where the heat is transferred by mixing hot solids with the oil containing solid.

This method of heat transfer can be used exclusively as well. A relatively new development is the LLNL HRS process, where feedstock and hot heat carrier are mixed in a fluidized bed and then are pyrolized in a fixed bed (UCRL-CONF-219767. Comparison of the Acceptability of Various Oil Shale Processes. Alan K. Burnham, James R. McConaghy. Mar. 14, 2006). The oil containing vapours being produced are extracted and fractionated. The solids are combusted, their fine particle content is discharged and the remaining matter is put into circulation as a heat carrier.

In another process according to U.S. Pat. No. 4,415,433A it is described, that the oil containing solid is fed to a fluidized bed at different heights. In such a way the bigger particles shall get a longer residence time, which they require for complete pyrolysis. All in all fluidized bed processes have not prevailed for the thermal treatment of materials like soil, as they require a costly pulverization of the feedstock and oil separation from the dusty pyrolysis gas is difficult.

An innovative process is currently introduced in the USA by Oil-Tech corporation. They heat oil shale in a vertical kiln by the means of built-in parts. Vapours are discharged in cross flow in a duct paralled to the main kiln (U.S. Pat. No. 7,229,547B2).

Many of the processes, which are described here, have deficits in the fields of process engineering, plant design or environmental impact. Oil yield often is insufficient, as much of the oil often remains as pyrolysis carbon in the solids, or it is cracked to gas or even burned. Plant design is often very complicated and thereby susceptible to faults. Toxic waste materials are produced and emissions exceed those required.

SUMMARY OF THE INVENTION

The present invention shall provide a process and an apparatus for the separation of hydrocarbons from oil containing solids, which can be realized in a commercial scale and allows for a maximum oil yield without or nearly without external energy supply. An efficient heat transfer is realized by simple process equipment.

This task is solved by the attributes of claim 1:

A process for the separation of hydrocarbons from oil containing solids, wherein the solids are heated up in one or several in series operated continuous mixers by addition of hot solids to a degree, that most of the hydrocarbon fraction is transferred into the mixer gas phase, whereupon these hydrocarbons are extracted and subsequently condensed as far as possible, wherein the mixer is positioned horizontally or slightly inclined in conveying direction and the mixer gas phase is cooled spontaneously.

An oil containing solid in the sense of the present invention is a solid, out of which on anaerobic thermal treatment a gas phase is separated, out of which an oil can be condensed. To such solids belong sand formations found in nature, which e.g. in Canada show a mineral oil content of up to 18% (oil sands), formations of marl or other kerogen containing clay sediments (oil shale), as well as soils contaminated by oil products. In oil shales the oil is contained in a precursor form, the so called kerogen. Oil is only produced by thermal treatment. These materials are specifically comprised by the expression “oil containing solid”. Among these are e.g. also harvest residues, wood and carbonization products, as far as from them hydrocarbons can be recovered by heat treatment and these are liquid or viscous at room temperature.

In accordance with a further preferred embodiment of the present invention the mixer gas phase of the process is cooled by a fluid upon exiting the mixer.

In accordance with a further preferred embodiment of the present invention the mixer gas phase is directed in counter current flow to the mixed solids phase.

In accordance with a further preferred embodiment of the present invention the temperature of the mixer gas phase is lowered by indirect cooling.

In accordance with a further preferred embodiment of the present invention the mixer gas phase is cooled by spraying a fluid in the form of dry or wet water steam.

In accordance with a further preferred embodiment of the present invention the mixer gas phase is cooled by addition of a fluid in the form of a non oxidizing gas, preferentially by not condensed gas from condensing the mixer gas phase.

In accordance with a further preferred embodiment of the present invention the diameter of the mixer gas phase in the claimed process gets bigger in its flow direction.

In accordance with a further preferred embodiment of the present invention the hot solids are added on at least one position to the mixer or the mixers in series.

In accordance with a further preferred embodiment of the present invention either the hot solids or both sorts of solids are added to the mixer from above through pipes, which are conducted through the mixer gas phase onto the mixed solid phase.

In accordance with a further preferred embodiment of the present invention the hot solids have a temperature of 500° C. to 1000° C. and the end temperature of mixing the solids is between 450° C. and 520° C.

In accordance with a further preferred embodiment of the present invention the mixer gas phase is cooled to a temperature below 400° C., preferentially to between 350° C. and 400° C.

In accordance with a further preferred embodiment of the present invention at a maximum particle size of 25 mm, determined as maximum 5% by weight larger than 25 mm according to DIN 66165 the maximum residence time of the solids in the mixer is 5 minutes.

In accordance with a further preferred embodiment of the present invention the total mass of the hot solids is one times to three times that of the oil containing solid.

In accordance with a further preferred embodiment of the present invention the hot solids are added to the mixer at two positions along its axis and namely at the beginning and in the middle section.

In accordance with a further preferred embodiment of the present invention the temperature of the hot solids is higher at the middle section addition position than at the beginning.

In accordance with a further preferred embodiment of the present invention the added amount at the middle section is less than 50% of that at the beginning of the mixer.

In accordance with a further preferred embodiment of the present invention the hot solids are fed to the mixer at least partially upstream the feeding point for the oil containing solid.

In accordance with a further preferred embodiment of the present invention the material produced in the mixer is incinerated and the produced ash is utilized as hot solids for heating up the oil containing solid.

In accordance with a further preferred embodiment of the present invention the combustion temperature is maintained between 700° C. and 950° C.

In accordance with a further preferred embodiment of the present invention the combustion is supported among others by the not condensed gas.

In accordance with a further preferred embodiment of the present invention the ash is conveyed partly or totally together with the flue gas to the mixer.

In accordance with a further preferred embodiment of the present invention the ash is separated from the flue gas by cyclones, which are partly operated in bypass.

In accordance with a further preferred embodiment of the present invention the flue gas is de-ashed and cleaned after heat recovery.

In accordance with a further preferred embodiment of the present invention the flue gas is utilized for indirect heating of the mixer via a muffle, however the mixer gas phase is not heated.

In accordance with a further preferred embodiment of the present invention the oil containing solid is preheated in direct exchange with part of the flue gas to a temperature, at which still less than 5% per weight of the hydrocarbons, which shall be produced, are transferred to the gas phase.

In accordance with a further preferred embodiment of the present invention the offgas from preheating is directed to an incineration, preferentially to the incineration of the deoiled solids.

In accordance with a further preferred embodiment of the present invention high calorific value solids are added to the oil containing solid or the deoiled solids.

In accordance with a further preferred embodiment of the present invention instead of or in addition to the incineration ash other hot solids are fed to the mixer.

In accordance with a further preferred embodiment of the present invention the mixing intensity decreases in flow direction.

In accordance with a further preferred embodiment of the present invention several mixers are put in series having different mixing intensity.

In accordance with a further preferred embodiment of the present invention the dust content of the mixer gas phase is decreased by increasing the gas phase space in direction of its exit.

In accordance with a further preferred embodiment of the present invention the mixer gas phase is diverted by built-in parts and is thereby de-dusted.

In accordance with a further preferred embodiment of the present invention the mixer gas phase is de-dusted after leaving the mixer and the solids being produced are recycled to the mixer.

Oil yield is maximized at minimal equipment size by an appropriate particle distribution and an accordant selection of mixer residence time and temperature profile. For this the oil containing solid and thereby also the hot solid shall be limited to a maximum particle size of 25 mm (maximum 5% weight larger than 25 mm according to DIN 66165). This allows for a sufficient heat and mass transfer in the mixer at a residence time of less than 5 minutes. In this case a separate soaking zone, which is common to other processes, is not required.

It is as well possible to use a bigger maximum particle size. This however prolongs the mixer residence time disproportionately. Grinding the oil containing solid to a much smaller size is on the other hand often not practical as well. It could cause considerable grinding costs. The higher fine particle fraction would partly be transferred into the gas phase and there increase the separation costs.

To create oil as well as to evaporate oil it is often necessary to reach a solids temperature of nearly 500° C. At the same time above 350° C. and intensified above 400° C. cracking begins, which produces at hydrocarbons, which are gaseous at room temperature, as well as a carbonaceous residue. To achieve a high oil yield these reactions must be minimized.

This is achieved by cooling the mixer gas phase already in the mixer or while extracting the gas phase out of the mixer. Various measures may be used. The method illustrated in example 1 consists of directing the mixer gas phase in counter current flow against the solids in a space above the mixed solid phase. At the mixer rear side, the solid phase discharge side, the oil containing solid is heated up to the highest temperature, as there its mixing with the hot solids is finished. This also results in the highest temperature of the mixer gas phase. En-route to the mixer front side colder vapours get into the gas phase, which are already created at lower temperatures from the oil containing solid. The feeding pipes of the oil containing solid and the hot solids may be extended through the mixer gas phase directly onto the mixing bed, in order not to increase the dust content of the gas and in case of the hot solids its temperature.

As far as during the gas cooling heavy oil from the mixer gas phase is condensing onto the solids, this is acceptable, as such heavy fractions are products with low demand. This condensate is mostly not lost, too. Higher grade oil is produced from it in the rear section of the mixer.

The gas phase has to be separated from the mixed solids latest on extraction out of the mixer. This is achieved by providing a gas space above the space, which is covered by the stirring unit. This gas space should be dimensioned for a separation of gas from solids, but it should also limit the gas residence time sufficiently.

Apparatus

The present invention further provides a mixer 2 to execute the aforementioned process wherein it has at least one horizontal or in flow direction slightly sloped shaft, which is/are fitted with wear resistant stirring devices.

In accordance with a further preferred embodiment of the present invention the mixer 2 comprises two paddle shafts, having a cover to extract the gas phase 4 at its highest point.

In accordance with a further preferred embodiment of the present invention the mixer 2 is in the form of a single shaft continuous mixer 2 with stirring devices as plough shares having different diameters, a minimum diameter at the gas extraction point 4, a maximum diameter at the solids feed position 1, 3, and a diameter between both at the discharge side 9 of the mixer 2.

In accordance with a further preferred embodiment of the present invention the mixer 2 further comprises a seal consisting of the conveyed solids to separate it against the other process stages and the outer atmosphere.

In accordance with a further preferred embodiment of the present invention the mixer 2 comprises water cooled shafts.

In the case of a mixer with a fixed drum it can be designed in many different ways. If a rotary drum is chosen, the dimensions of the gas space are predetermined by the filling degree at the rear side and the slope of the drum.

The mixer gas phase in the mixer section, where gas temperatures might be above 400° C., may also be cooled by addition of colder gas or liquids, which are sprayed into the vessel. Saturated steam or partly circulated not condensed gas, which is resulting from the condensing unit after the mixer, may be used. With counter current flow a favourable addition position for the added gas is at the top of the mixer rear side. In addition to the cooling the added gas has a strip effect and shortens the gas phase residence time. The gas phase temperature profile, which is lowering from the rear to the front side, is affected by addition of a large gas stream. This is an advantage, as long as the gas phase does not come into intensive contact with the mixed solid phase.

A further alternative is to cool the gas phase by a water jet, which does not get into contact with the solid phase (see example 2). This is advantageous, if vapours are condensed by a scrubber.

Main task of the mixer is to heat the oil containing solid by addition of hot solids. In the most simple way the hot solids as well as the oil containing solid are added at the mixer front side. If the oil containing solid has a tendency to baking, it might give sense to add the hot solids at least partly upstream.

To guarantee a good cooling of the mixer gas phase, the hot solids addition may also be spread along the length of the mixer. A first part is given to the front side, where it already transfers much of its heat to the oil containing solid. Thus part of the oil already is evaporated and extracted at the minimum temperature possible. The residual oil remains in the solid phase. More to the mixer rear side further hot solids are added. This increases the temperature in the mixer solid phase continuously and additional oil is extracted. The distributed heat addition supports local temperature minimization of the mixer gas phase. It decreases at the same time an overheating of the oil containing solid and thereby decreases cracking and coking in solid and liquid phase.

An indirect heating of the mixer solid phase or cooling of the gas phase may support the desired temperature profile.

Different equipment types may be used as mixers, e.g. ploughshare mixers or double shaft paddle mixers, as well as free fall drum mixers. As the mixer size, in particular its length, is limited by mechanical reasons, it might give sense to put several mixers in series. The mixer should convey the solids horizontally or with a slight slope in conveying direction, which supports the transport.

The mixer has a stirred solids zone and above the mixer gas phase. It might be practical to increase the gas phase space from the rear to the front side. This is to adapt it to the increasing gas amount. At the front gas extraction point gas velocity should be low enough to limit the extracted amount of dust.

This may be supported by dust separating easy to clean built-in parts. The stirrer units like paddles, lifters or ploughshares should at the gas extraction position be designed to minimize dust creation.

When using mixers with a stirring shaft wear has to be minimized. Materials have to be selected accordingly and hard facing is an option. Amount of stirring units or their design may be different, if mixers are put in series. At the first contact of the different solids an intensive mixing is required, in the rear zone a lower mixing intensity might be sufficient.

The mixer shall be operated at underpressure. This is advantageous to avoid emissions. On the other hand it decreases the oil boiling temperature, however only slightly. The chosen pressure depends on different criteria. The applicability of the mixer for underpressure operation affects them, also how the low boiling oil fractions can be condensed. When treating oil shale, wood and similar materials a strong underpressure is e.g. not required, since irrespective of the pressure a temperature of approximately 500° C. is required to create the desired oil fractions.

In any case air leakage into the mixer must be minimized. Therefore product seals can be provided at the solids feed and discharge points. Rotary locks may be used as well.

Oil vapours extracted out of the mixer will contain dust in spite of prior minimization. It can be separated in mechanical filters or electric filters. Partial separation might be effected e.g. by a cyclone.

At the subsequent oil condensation e.g. by a combination of venture and counter current scrubbers the remaining dust gets into the liquid phase. It might be later separated from the condensed oil by decanter centrifuges and be recycled into the process.

Even if the oil containing solid is low in water content or predried, a small amount of condensate water with a high content of organics is formed. This may be recycled to a predryer for the oil containing solid.

The non condensed gas, containing primarily hydrocarbons and hydrogen, may be partly recycled to the mixer as described above, it may be utilized within the process for the combustion of the mixer output or it may be used as substitute natural gas outside of the process.

The solids discharged out of the mixer, from which oil is removed, are incinerated. Several well known processes like fluidized or entrained bed combustion can be adopted. As in comparison to conventional power stations the relationship of solids to flue gas is high and particle size is bigger, it might be advantageous to do incineration in a rotary kiln. In many cases the pyrolysis carbon created in the mixer will not be sufficient to support combustion. In addition to feeding the non condensed gas a combustion of solid fuels is feasible.

The required temperature of the incineration is limited by different factors. If the solids contain calcium carbonate, it might not be heated to more than 800° C. in order to avoid carbon dioxide emissions and higher energy consumption. But the temperature should be chosen high enough to completely incinerate the solids and to avoid carbon monoxide formation. Because of material selection temperatures should be kept as low as possible in each stage.

After incineration a part of the hot solids is fed into the mixer. It may e.g. be blown to the mixer together with the flue gas, be separated there by hot gas cyclones and then be added to the oil containing solid.

It is feasible as well to add not only the incineration ash but additional hot solids to the mixer. This might be required, if the oil containing solid has only a low amount of mineral matter, e.g. when feeding biological raw materials like wood or harvest residues.

Excess solids have to be discharged from the system. They may e.g. discharged directly out of the combustion chamber. As far as they consist of a fine particle fraction, which remains in the flue gas after separating the hot solids, which are added to the mixer, they may be mechanically separated after cooling the flue gas.

It is preferred to combine flue gas cooling with heat recovery. Electricity, which is required in high amounts for the process, might e.g. be produced via a boiler. A heat exchanger might as well preheat combustion air or the flue gas might indirectly heat the mixer solid phase by a muffle.

For many applications a further heat recovery from the flue gas might be advantageous. Usually the oil containing solid in its original stage will have some moisture and often oil evaporation will start only above of e.g. 200° C. In these cases the oil containing solid should be preheated and dried before entering the mixer.

Drying can be effected by mixing with hot solids from the incineration stage. Its recycle rate should however be minimized. Alternatively the hot flue gas can be indirectly or more favourably directly contacted with the oil containing solid. If in case of direct heating the drier off-gas contains organic compounds, it should be directed to the incineration stage. If an organic content can be avoided, it is thermodynamically more favourable to emit the gas after cleaning it without reheating.

After one or several of the described heat recovery options are completed, the flue gas is cleaned. Usually the flue gas may be treated by the same processes, which are state of the art in power stations or thermal waste treatment.

The process combines numerous advantages.

By lowering the temperature in the mixer gas phase cracking is avoided to a large extent and oil yield is maximized. This can be effected by counter current flow in the mixer, by addition of strip gas, addition of the hot solids at different points and other procedures.

Compared to previous methods for the extraction of bitumen from oil sands the process produces a low viscosity distillate oil.

A robust equipment with low wear is used, which is well proven from large-scale operation in environmental technology, power plants or refineries. Indirect heat transfer is avoided. Throughout the process high capacity per space and time is achieved, which allows for application in projects with a throughput of several million metric tons per year.

The energy, which is contained in the oil containing solid is nearly full utilized, as far as possible to produce oil and gas for external use, the rest to produce the required process heat while applying heat recovery.

The whole process is environmentally friendly. Its solid residue does not contain possibly toxic organic compounds. The waste gas complies with modern emission regulations. Waste water from the process may not be produced. By maximizing oil yield a minimization of specific carbon dioxide emissions is achieved.

EXAMPLES

The present invention will now be explained in greater detail with reference to three figures. For the sake of greater clarity, reference is hereby made to the following list of reference numerals:

• 1 Oil containing solid
• 2 Continuous mixer
• 3 Hot solids
• 4 Vapours
• 5 Oil fraction
• 6 Dust
• 7 Not condensed gas
• 8 Condensing stage
• 9 Deoiled solids
• 10 Air
• 11 Incineration
• 12 Flue gas
• 13 Flue gas treatment unit
• 14 Ash
• 15 Residual flue gas
• 16 Rotary drum
• 17 Solids containing flue gas
• 18 Flue gas from predryer
• 19 Dried oil containing solid
• 20 Cyclone
• 21 Heat exchanger
• 22 Hot gas filter
• 23 Water condensate
• 24 Liquid jet
• 25 Weir

The following is shown:

Example 1 in combination with FIG. 1 shows the process according to the invention, where the vapours in the continuous mixer 2 are cooled by counter current flow of solids and gas phase.

Example 2 in combination with FIG. 2 shows an alternative embodiment of the invention, where the vapours are cooled by a liquid when exiting the continuous mixer 2.

Example 3 in combination with FIG. 3 shows an additional alternative embodiment of the invention, where among other features the oil containing solid is predried, and the not condensed gas is utilized to heat the incineration 11 and is utilized as a strip gas in the continuous mixer 2.

Example 1

In FIG. 1 100 parts of an oil containing solid 1, which in this case consists of predried oil shale at 230° C. with an oil content of 19% by weight according to distillation in the Fisher retort (ISO 647-1974-11), are mixed in a horizontal ploughshare mixer 2 with 140 parts of hot solids at 780° C., an ash from incineration of the deoiled solids. The first ploughshare in the mixer has a lower diameter compared to the other ones. The solids are fed through feeding pipes, until they are just above the plough shares. 214 parts of 505° C. hot deoiled solids 9 are discharged from the mixer at the solids discharge side. 26 parts of vapours 4 are produced in the mixer, which consist of 18 parts of oil fraction, which is liquid at 25° C., of 3 parts of substances, which are gaseous at 25° C. (not condensed gas), and of 1 part of water vapour. The vapours 4 are in counter current flow against the solids inside a mixer cover, which gets wider in gas flow direction, towards the solids feed side of the mixer and are extracted there at 390° C.

Example 2

Again the oil containing solid 1 of example 1 is mixed with the hot solids 3. Unlike example 1 the vapours 4 are directed in parallel flow with the solids as shown in FIG. 2. They are cooled by the liquid jet 24 directly when exiting the mixer. To control the solids level in the mixer a weir 25 is fixed to the solids discharge point.

Example 3

1000 parts of the oil containing solid, an oil sand 1, maximum particle size 20 mm at a temperature of 20° C., consisting of 710 parts of mineral matter, 195 parts of bitumen and 95 parts of water, are dried as shown in FIG. 3 after addition of 5 parts of water condensate 23, which are recovered in the process, in a rotary drum 16 in counter current flow against 980 parts of 800° C. hot, solids containing flue gas 17 and are heated to 250° C. The flue gas from predryer 18 thereby cooled to 300° C. is recycled to incineration 11.

900 parts of dried oil containing solid 19 consisting of 190 parts of oil and 5 parts of residual water are conveyed via a product seal to a double shaft paddle mixer 2, whose paddles are protected against wear by hard facing. The mixer cover gets higher in direction to the feeding side. Above the paddles thereby exists a gas phase, which gets a higher diameter in counter direction to the solids flow. Into the feeding section 800 parts of hot solids 3 at 800° C. are fed as cyclone ash, into the middle of the mixer are fed an additional 700 parts. The solids feeding pipes are conducted through the cover to the paddles. Through the rear side cover plate of the mixer 20 parts of not condensed gas 7 at 12° C. are fed into the mixer gas phase. 180 parts of vapours 4 are extracted in the front region of the mixer at 370° C. and are separated in a hot gas filter 22 of 10 parts dust 6, which is returned to the mixer. The following condensing stage 8 consists of a counter current scrubber, whose liquid phase is cooled by cooling water, and a second condensing stage, where a refrigerator puts the residual gas to 8° C. 105 parts of oil fraction 5 may be used as a synthetic mineral oil after separation of 5 parts of water condensate 23. The water 23 is recycled to the feeding material 1. 20 parts of the not condensed gas 7 out of a total mass of 60 parts are processed to substitute natural gas, 20 parts are required to support incineration 11, 20 parts are recycled to mixer 2.

2250 parts of deoiled solids 3 are transported out of mixer 2 via a product seal to incineration 11, where the carbon content of 45 parts is partially combusted by 800 parts of preheated air 10. Into this chamber also flows the flue gas 18 from predryer 16 and the not condensed gas 7. Out of 1455 parts flue gas 12 at 800° C. the hot solids 3 are separated in cyclones 20. After partial utilization of the solids containing flue gas 17 to predry wet input oil sand inside rotary drum 16 the remaining 1675 parts are used to pre-heat combustion air 10 in heat exchanger 21 and also to produce steam for power generation. Finally 733 parts of ash 14 are separated in flue gas treatment unit 13. 940 parts of residual flue gas 15 are cleaned and emitted.

Claims

1.-38. (canceled)

39. A process for the separation of hydrocarbons from oil-containing solids, comprising heating the oil-containing solids in one or several in-series operated continuous mixers by addition of hot solids to the oil-containing solids, thereby forming a mixed solids phase, wherein heating is conducted at a temperature at which most of a hydrocarbon fraction in the oil-containing solids is transferred into a gas phase in the mixer(s), wherein the mixer(s) are positioned horizontally or slightly inclined in a conveying direction and wherein the mixer gas phase is cooled simultaneously to a temperature below 400° C. before or upon exiting the mixer(s).

40. A process according to claim 39, wherein the mixer gas phase is cooled by a fluid upon exiting the mixer(s).

41. A process according to claim 39, wherein the mixer gas phase is directed in counter current flow to the mixed solids phase and is thereby cooled.

42. A process according to claim 39, wherein the temperature of the mixer gas phase is lowered by indirect cooling.

43. A process according to claim 39, wherein the mixer gas phase is cooled by spraying a fluid in the form of dry or wet water steam.

44. A process according to claim 39, wherein the mixer gas phase is cooled by addition of a fluid in the form of a non oxidizing gas.

45. A process according to claim 44, wherein the non oxidizing gas comprises non condensed gas from condensation of the mixer gas phase.

46. A process according to claim 39, wherein the diameter of the mixer gas phase in the mixer(s) increases in its flow direction.

47. A process according to claim 39, wherein the hot solids are added to the mixer(s) at more than one position.

48. A process according to claim 39, wherein either the hot solids or both the hot solids and the oil-containing solids are added to the mixer(s) through pipes which extend through the mixer gas phase onto the mixed solids phase.

49. A process according to claim 39, wherein the hot solids have a temperature of 600° C. to 1000° C. and the highest temperature of the mixed solids phase is between 450° C. and 520° C.

50. A process according to claim 39, wherein the mixer gas phase is cooled to a temperature between 350° C. and 400° C. before exiting the mixer(s).

51. A process according to claim 39, wherein the maximum particle size of the oil-containing solids is 25 mm, determined as a maximum of 5% by weight larger than 25 mm according to DIN 66165, and the maximum residence time of the oil-containing solids and of the hot solids in the mixer is 5 minutes.

52. A process according to claim 39, wherein the total mass of the hot solids in the mixer(s) is one to three times that of the oil-containing solids.

53. A process according to claim 39, wherein the hot solids are added to the mixer(s) at two positions along its axis, at an inlet end and in a middle section.

54. A process according to claim 53, wherein the temperature of the hot solids is higher at the middle section addition position than at the inlet end addition position.

55. A process according to claim 53, wherein the amount of hot solids added at the middle section is less than 50% of that added at the inlet end.

56. A process according to claim 39, wherein the hot solids are fed to the mixer(s) at least partially upstream of a feeding point for the oil-containing solids.

57. A process according to claim 39, wherein de-oiled solids exiting the mixer are incinerated and resulting ash is utilized as hot solids for heating the oil-containing solids.

58. A process according to claim 57, wherein the incineration combustion temperature is maintained between 700° C. and 950° C.

59. A process according to claim 57, wherein non condensed gas from condensation of the mixer gas phase is added to the incineration combustion.

60. A process according to claim 57, wherein the ash is conveyed partly or totally together with incineration flue gas to the mixer(s).

61. A process according to claim 57, wherein at least a portion of the ash is separated from incineration flue gas by one or more cyclones.

62. A process according to claim 57, wherein incineration flue gas is de-ashed and cleaned after heat recovery.

63. A process according to claim 57, wherein incineration flue gas is utilized for indirect heating of the mixer(s) via a muffle, without heating the mixer gas phase.

64. A process according to claim 57, wherein the oil-containing solids are preheated in direct exchange with a portion of incineration flue gas to a temperature at which less than 5% by weight of the hydrocarbons which shall be produced are transferred to the gas phase.

65. A process according to claim 64, wherein off gas from preheating is directed to the incineration of the de-oiled solids.

66. A process according to claim 65, wherein high calorific value solids are added to the oil-containing solids or the de-oiled solids.

67. A process according to claim 57, wherein hot solids in addition to the incineration ash are fed to the mixer(s).

68. A process according to claim 39, wherein the mixing intensity decreases in the mixed solids flow direction.

69. A process according to claim 39, wherein several mixers are provided in series having different mixing intensities.

70. A process according to claim 39, wherein a dust content of the mixer gas phase is decreased by increasing the mixer gas phase space in the flow direction of the mixer gas phase.

71. A process according to claim 39, wherein the mixer gas phase is diverted by built-in parts and is thereby de-dusted.

72. A process according to claim 39, wherein the mixer gas phase is de-dusted after leaving the mixer(s) and resulting solids from the de-dusting are recycled to the mixer(s).

73. A mixer for separating hydrocarbons from oil-containing solids according to the process of claim 39, comprising a continuous mixer having at least one horizontal or in flow direction slightly sloped shaft, fitted with wear resistant stifling devices.

74. A mixer according to claim 73, comprising two paddle shafts and having a cover to extract the mixer gas phase at its highest point in the mixer.

75. A mixer according to claim 73, comprising a single shaft continuous mixer with stirring devices as plough shares having different diameters, the stifling devices having a minimum diameter at a gas exit, a maximum diameter at a solids feed position, and a diameter between the maximum diameter and the minimum diameter at a solids discharge side of the mixer.

76. A mixer according to claim 73, further comprising a seal consisting of the conveyed solids to separate the mixer from other process stages and an outer atmosphere.

77. A mixer according to claim 73, comprising water cooled shafts.