WO2010034621A1

WO2010034621A1 - Method for producing oil coke with improved microstructure on the basis of shale oil

Info

Publication number: WO2010034621A1
Application number: PCT/EP2009/061740
Authority: WO
Inventors: Nikolai Sedov; Igor Velmar; Robert Ehin; Zimfira Prelovskaja
Original assignee: Vkg Oil As
Priority date: 2008-09-24
Filing date: 2009-09-10
Publication date: 2010-04-01
Also published as: EE05369B1; EE200800060A; EA201001600A1; WO2010034621A4; EA017738B1

Abstract

The invention is provided for producing oil coke on the basis of oil shale. The oil coke is of improved quality having the microstructure similar to the microstructure of needle coke. As raw material a heavy fraction of shale oil with boiling point from 320 °C extracted from the residual product with boiling point from 350 °C of the atmospheric distillation of shale oil in the process of coking is used. The raw material is inserted into the coke cube and after that boiled, whereas during the whole boiling stage the temperature of raw material is continuously increased. Starting from the emerging of the coke bulk the temperature of the cube is increased to 720-760 °C and kept on this level until the end of the heating of oil coke. After that oil coke is annealed. The vaporised fractions emerged are processed and re-utilized.

Description

Method for producing oil coke with improved microstructure on the basis of shale oil

Technical field

The invention relates to the field of chemical industry and is provided for producing on the basis of shale oil of oil coke with improved microstructure that is used for manufacturing of powerful graphite electrodes having a large diameter in the range of 400-700 mm. Graphite electrodes of this kind find application in power supplies for equipment of chemical industry and furnaces.

Prior art

From prior art producing coke from organic raw materials is known. For example, a method for producing petroleum-coke in a horizontal coke cube is known, according to which heavier fractions, obtained in thermal treatment of petroleum, are used as raw material for producing coke. The method provides pre-heating of the coke cube during 5-10 minutes, necessary for vaporizing water possibly present in the cube. At the same time steam is fed into the cube to remove air from the cube, thus avoiding forming of the explosive mixture of air and vaporized fractions of raw material fed into the cube. After that the raw material for coke is fed into the cube to fill up 33% of the volume and the temperature of the raw material is raised to start the coking process of the raw material. When the temperature of the raw material reaches up to 445-460 ⁰C, the temperature in the cube starts to drop, meaning that the process of forming of the coke bulk has come to an end and from this moment drying of the coke starts, which process is also called heating through of the coke. Drying lasts for 2-3 hours after which the burners heating the cube are switched off and in 0,5-1 hours the steam is fed into the cube in order to remove residual gases and to cool the coke. Further the prepared coke is removed from the cube and a new cycle is started again as explained above (see also A.Φ.Kpacκ>κoB. ,,HeφτflH0M KOKC". H3flaτeπbcτB0 «XMMM?I», 1968, pp 72-81 ).

Also a method for producing coke on the basis of petroleum is known, the coke produced this way is used for making anodes and other graphite products.

According to the method the raw material is fed into the coke container at a temperature of 475-485 ⁰C to be coked for 14-36 hours and then the coke is removed from the coke container (see also Russian Federation Patent No. 2296151 ).

Due to the rapid growth of the price of petroleum, also the price of the coke produced on the basis of petroleum has increased and therefore efforts are made to produce coke from other organic raw materials, including also shale-oil which is the product of thermal treatment (dry distillation) of shale. For example, a method for producing oil coke on the basis of shale-oil is known, whereas as a raw material for oil coke residual products with BP starting from 350 ⁰C and obtained in distilling of shale-oil at atmospheric pressure, as well as heavy fraction with BP starting from 320 ⁰C and separated from the same residual product in the process of coking are used, at that either residual products or heavy fraction are used as raw material but not both of them at the same time. The raw material for producing coke is heated up to 150-200 ⁰C in order to make it sufficiently fluid for transportation through pipelines and further the process of preparing coke in the coke cube is carried out in a series of identical cycles, whereas each cycle works as follows: the temperature in the coke cube furnace is raised at least up to 250 ⁰C, upon raising of the temperature in the cube up to 150 ⁰C, that insures vaporizing of the water possibly remaining in the cube, all inlets and outlets of the cube are closed hermetically, after which steam having temperature of 150 ⁰C is fed into the cube for the purpose of checking its impermeability. When during a specified period of time, for example 3-5 minutes, the pressure in the cube does not decrease, the cube has been tested for impermeability. After testing of impermeability the steam is removed from the cube and the raw material is introduced into the cube to fill up 25-35% of its volume. After that raising of the temperature of the raw material in the coke cube is started by burners allocated under the bottom of the cube. When the temperature is being raised, lighter evaporating fractures are led out of the cube and when the temperature of the raw material left in the cube reaches BP, active vaporization of lighter fractions to be led out of the cube is starting. After reaching of BP the raw material goes on boiling at this temperature until the foam starts to form in the coke cube and a rapid raise in temperature takes place. From this instant active coking starts. When the raw material is boiling and coke is forming, evaporated heavier fractions are led out of the cube and when being condensated, they produce heavy fraction with a BP starting from 320 ⁰C, which is used as raw material for coke. When the process of forming of coke has terminated, the temperature in the cube drops rapidly and the temperature of the furnace is increased to ensure the necessary temperature for the following heating through of the coke. The heating through of the coke lasts 1 ,5-2 hours, whereupon the burners under the bottom of the cube are switched off and the heat stored in the coke keeps on annealing it up to 2 hours. During this time interval the structure of the coke reaches the requested strength on account of residual heat stored in the coke. After termination of annealing the ready coke is removed from the container (the described method is applied by an Estonian company VKG Oil Ltd in Kohtla-Jarve, Estonia).

The known method enables to produce oil coke which may successfully replace petroleum coke in many ways of usage, for example for making electrodes to be used in aluminium industry and metallurgy. Unfortunately, the oil coke produced on the basis of shale-oil according to the method as described has non-uniform microstructure, wherefore electrodes manufactured from such oil coke have high resistance and they withstand current densities up to 18-20 A/cm². At higher current densities such electrodes cause a substantial power dissipation, electrodes become overheated and disintegrate.

For sufficient power supply of modern chemical industry and metallurgy equipment it is necessary to ensure normal operation of powerful graphite electrodes at current densities in the range of 25-30 A/cm². Such current densities can be ensured by coke having acicular microstructure (needle shaped coke), which at present is manufactured either from black coal (Japan) or from crude oil (U.S.A.). A small number of producers and high market demand has led to a substantial shortage of this kind of product. Taking into consideration market demand it is in every way rational to organize production of coke having said parameters using other sources of raw material, first of all oil shale, that according to the information obtained by the applicant has not been done so far.

Object and subject matter of the invention

Taking into account the aforesaid, the object of present invention is to propose a method for producing of oil coke on the basis of shale oil, having improved microstructure similar to the microstructure of acicular coke (needle coke) produced from crude oil or black coal, wherefore such oil coke ensures microstructure index in the range of 4,9-5,1 and is quite suitable for producing, 5 amongst others, powerful graphite electrodes.

In order to achieve the objective according to the method, the raw material is introduced into the coke cube and thereafter coked, for which purpose the raw material is heated up to boiling temperature, whereupon the raw material is boiled until forming of the coke bulk, the formed oil coke is heated through, annealed and io when annealing has been completed, the prepared oil coke is removed from the coke-cube;

as a raw material a heavy fraction, having boiling temperature of 320 ⁰C and separated during coking process from a residual product of distilling of oil shale at atmospheric pressure and having boiling temperature of 350 ⁰C, is used;

is in order to start boiling the temperature of the raw material is raised to boiling point and during further boiling the temperature is smoothly raised to 390-410 ⁰C;

beginning of coking of the raw material is established by the start of foam release in the coke cube;

after the start of coking of the raw material the furnace temperature is raised to 20 720-780 ⁰C and said temperature is maintained until the end of heating through of the formed coke.

In order to bring the temperature of raw material to boiling temperature, the temperature of furnace is raised at a speed of 3-6 °C/min to the temperature of 680-720 ⁰C until the start of release of light fractions, after what the temperature of 25 the furnace is reduced to 430-460 ⁰C at a speed of 3-6 °C/min.

Smooth raising of the temperature of raw material is effected during the whole boiling period.

In order to raise the temperature of raw material continuously during boiling the temperature of the furnace is steadily raised starting from 430-460 ⁰C until the coking of raw material starts.

The temperature of the raw material introduced into the cube is at least 180 ⁰C.

Brief description of the drawings

The invention is illustrated by the means of drawings, whereby:

Figure 1 depicts the flow chart of carrying out of the method according to the invention;

Figure 2 shows a schematic diagram of the main element of the equipment for carrying out of the method according to the invention - the coke cube, whereby the arrows next to the valves in the drawing indicate the direction of flow of the material in pipelines when the respective valve is opened;

Fig 3 shows a schematic diagram of the equipment for carrying out of the method according to the invention;

Fig 4 shows temperature curvatures of the oil coke obtaining process in "time- temperature" coordinates, whereby permanent line A indicates the temperature in the material to be coked, permanent line B indicates the temperature of the furnace and broken line C indicates the temperature in the gas outlet pipe of the cube.

Detailed description of the exemplary embodiment of the invention

The flow chart of the method according to the invention is presented in Fig 1. For producing of oil coke having improved quality a heavy fraction, having a boiling temperature starting from 320 ⁰C and separated during coking process from a residual product of distilling of oil shale at atmospheric pressure and having boiling temperature starting from 350 ⁰C, is used as a raw material. The raw material in its tank is kept at a temperature at least 180 ⁰C for normal flowability in pipelines.

Further process of preparing coke is cyclic, whereas each cycle starts with delivering the raw material into the coke cube and ends with discharging the prepared oil coke. Next one cycle of the process is described.

Prior to introducing raw material into the coke cube, its permeability is checked. For that purpose the temperature in the empty coke cube is raised at least up to 250 ⁰C, after that all inlets and outlets of the coke cube are closed and pre-heated steam having a temperature at least 150 ⁰C is fed into the coke cube. When the pressure of the steam in the cube during a certain period of time, for example 2-5 minutes, does not decrease, it is concluded that the cube is air-tight. After that the steam is removed from the coke cube.

The quantity of the raw material to be fed into the coke cube constitutes up to 50% of the volume of the cube. It is not to the purpose to introduce a greater amount of the raw material, inasmuch as the raw material expands substantially and when a greater amount is inserted, it will fill up the coke cube completely, thus making it impossible for the process to carry on.

After the necessary quantity of preheated raw material has been introduced into the cube, the temperature of the furnace is raised in order to bring the raw material to the drip-point of 320 ⁰C. For this purpose the temperature of the furnace is raised relatively rapidly to 680-720 ⁰C and is kept at this temperature until lighter fractions start to release (vaporize) from the raw material. After that, in order to avoid overheating of the raw material during further boiling, that will halt the formation of coke's necessary structure, the temperature of the furnace is relatively fast reduced to 430-460 ⁰C with a consideration that to the moment of reaching of the said furnace temperature, the temperature of the raw material has already exceeded drip-point and intensive boiling of the raw material has started. This instant is taken as a starting point of controllable boiling.

After that the temperature of the raw material is smoothly raised by increasing the temperature of the furnace by 0,1 -0,3 °C/min. This kind of temperature raising takes place until the end of boiling of the raw material, whereby the applicant has established that raising of the temperature at the aforesaid speed ensures the best microstructure index of the coke to be formed. Whereas the necessary preconditions for forming of coke's microstructure are established during boiling process of the raw material, then the tests have indicated that namely a smooth and as linear as possible raising of the temperature up to the limit of 390-410 ⁰C gives the coke the best possible microstructure. Upon raising the temperature of the raw material too rapidly there is no time for the necessary preconditions for forming of coke's microstructure to develop, whereas raising of the temperature too slowly substantially increases the time needed for the process.

The boiling is finished, when in the coke cube there starts to appear foam on the raw material, evidencing that formation of coke bulk has started resulting in a temperature raise in the coke cube. In order to ensure further coking the temperature of the furnace is rapidly raised to 720-780 ⁰C and is kept on that level until the end of coking and also during the following heating through lasting at least for 2 hours. Thereafter the burners heating the furnace are switched off and the heat stored in the coke keeps on annealing it also for approximately 2 hours. After annealing the coke is ready to be removed from the coke cube.

Next a complex embodiment of the method according to the invention for producing of oil coke of improved quality on the basis of shale oil by means of a particular apparatus is described, that together with implementation of the method enables residual products (vaporized fractions, water, etc) formed during the production process to be utilized or to be directed back into the production process if necessary.

A coke cube, the principal structure of which is shown in Fig 2, is the main unit of the apparatus. The coke cube 1000 comprises a cylindrical horizontal reservoir 1100 and a furnace 1200 underneath it. In the upper part of the reservoir 1100 there are three openings 1101 , 1102 and 1103, whereby openings 1101 and 1102 are inlets, through which steam and raw material are respectively introduced into the coke cube, and opening 1103 is an outlet, through which gases and vapours emerging during coke formation process are removed from the coke cube. In the outlet pipe, originating from opening 1103, there is installed a thermocouple 1105 for measuring the temperature of gaseous residues leaving the coke cube. The temperature of gaseous residues is used for monitoring and controlling of the burning process going on in furnace 1200. In the outlet pipe there is valve 1104 that is necessary when checking the impermeability of the coke cube. Inlets 1101 - 1102 are also equipped with valves 1106 and 1107. In the cylindrical reservoir of the coke cube (approximately 90 cm from the lowest point of its bottom) there is also a thermocouple 1108 for measuring the temperature of raw material.

In the wall 1201 of the coke cube furnace 1200 there is an opening 1202 through which the burners installed in the furnace (not shown in the figure) are connected to the tanks of heating gas. These connections are made through valve 1203, with which the supply of heating gas to the burners is controlled. The bottom of the furnace is realized as inclined plane 1204 extending until vertical partition wall 1205, the height of which being a little bit smaller than the height of the furnace and which is in proximity to the opposite wall 1206 of the furnace chamber. In this wall near the furnace bottom there is an opening 1207 through which combustion gases leave furnace 1200. Above partition wall 1205 and very close to the bottom of reservoir 1100 there is installed thermocouple 1208 which is used for indirect measurement of the temperature of the bottom of reservoir 1100 - though the thermocouple 1208 measures the temperature in the fireplace (furnace), due to its proximate vicinity to the bottom of the reservoir 1100 the temperature of furnace in the location of thermocouple 1208 is practically equal to the temperature of the bottom of reservoir 1100. Therefore, the term "temperature of the furnace" used hereinafter practically means also the temperature of the bottom of reservoir 1100.

Fig 3 shows the complex apparatus used for implementing of the present invention. The apparatus includes three main units - the coke cube 1000, the structure of which has been in detail described above, unit 2000 for processing gaseous compounds removed from the coke cube and unit 3000 for collecting processed residues and returning them back into process.

The unit 2000 for processing gaseous compounds includes intermediate tank 2010 and two air coolers 2020 and 2030. Intermediate tank 2010 has an inlet 2011 that is connected to the valve 1104 of the coke cube 1000 and two outlets 2012 and 2013. Outlet 2012 is connected to the inlet 2021 of the first air cooler 2020 in order to forward uncondensed gaseous compounds from the intermediate tank 2010 to the air cooler 2020, and outlet 2013 is used for discharging of heavy distillate condensed in the intermediate tank 2010 into a storage tank for said product (not shown in the figure). Air cooler 2020 has an outlet 2023 for condensed fractions that is connected to the unit 3000 for collecting and returning the processed residues, and outlet 2022 for gaseous fractions connected to the inlet 2031 of the second air cooler 2030. The condensed fractions outlet 2033 of the second air cooler 2030 is connected to the unit 3000 for collecting and returning into process the processed residues, and through outlet 2032 for gaseous fractions the coke gas outflows and is directed back into the manufacturing process where it may be used for heating of the furnace 1200.

The unit 3000 for collecting processed residues and returning them into the manufacturing process includes tanks 3010 and 3020 and pumps 3030 and 3040. The tank 3010 is intended for collecting condensed light distillate and tank 3020 is intended for collecting of condensed petrol and water. Inlet 3011 of tank 3010 is connected to the outlet 2023 of the first air cooler 2020 of the unit 2000, and outlet 3012 is connected to the inlet 3031 of a pump 3030 that returns light distillate to the production process. Inlet 3021 of the tank 3020 is connected to the outlet 2033 of the second air cooler 2030 of the unit 2000, from where condensed petrol and water are removed, and outlet 3022 is connected to inlet 3041 of the pump 3040 returning petrol and water back into the production process.

The method is realized as a cyclic process using the above described apparatus, whereby each cycle is performed as follows.

Prior to introducing raw material into the reservoir 1100 of the coke cube 1000 all the inlet and outlet valves of the reservoir 1100 are closed, except for the valve 1104 through which the reservoir 1100 is connected to the unit 2000 for processing gaseous compounds. Thereafter through valve 1203 heating gas is introduced into the furnace 1200, which upon burning starts to heat the lower surface of the reservoir 1100 of the coke cube. In Figure 4 the starting moment of heating is indicated by t-i at which point the curve B makes a sharp rise upwards and within a few minutes reaches the temperature of approximately 350-370 ⁰C. Residual products remaining in the reservoir 1100 from the previous cycle evaporate, leave the reservoir and are collected in the intermediate tank 2010 of the unit 2000 for processing gaseous compounds. When the temperature in the reservoir 1100 is at least 250 ⁰C, the valve 1104 is closed and the valve 1106 is opened, through which pressurized superheated water steam is introduced into the reservoir 1100 at a temperature of at least 150 ⁰C in order to avoid its condensation in the reservoir 1100. When the necessary pressure level in the reservoir 1100 has been reached, the valve 1106 is closed and within 2 to 5 minutes the change of pressure in the reservoir 1100 is checked. In case the pressure does not drop during this time period, meaning that the reservoir 1100 is air tight, the valve 1104 is opened and used steam, which contains also vapours of residual products left in the reservoir 1100 from the previous cycle, is led into the intermediate tank 2010 of the unit 2000 for processing gaseous compounds.

Thereafter the valve 1 104 is left open, in addition the valve 1107 is also opened and introducing of raw material, that in order to assure its stable flow in the pipelines has previously been heated up to the temperature of at least 180 ⁰C, into reservoir 1100 is started. In Fig 4 the starting moment of filling the reservoir is indicated by t₂ where the temperature curvature A of raw material has its starting point (preheated raw material at a temperature of at least 180 ⁰C is fed in). The amount of the raw material introduced into the reservoir 1100 is 40-50% of its volume.

After feeding the necessary amount of raw material into the reservoir 1100 the valve 1107 is closed (instant t₃) and by intensifying heating of the furnace 1200 the temperature of the raw material starts to raise (during this period the temperature of the furnace and accordingly also of the bottom of the reservoir 1100 exceeds

700 ⁰C, as is seen in Fig 4 from curvature B for the time interval t₃-t₄). For that purpose the temperature of the furnace is raised at a speed of 3-6 °C/min until the temperature of the furnace reaches the range of 680-720 ⁰C. Vapours of lighter fractions formed in the reservoir 1100 during the temperature raise leave the reservoir 1100 through an open valve 1104.

The temperature of the furnace 1200 is kept on the reached level until the temperature of the raw material reaches boiling reference temperature of 320 ⁰C. Reaching this temperature is indicated by intensive vaporization of lighter fractions from the raw material resulting in a drop of temperature in the outlet pipe, measured by thermocouple 1105, which upon reaching of drip-point displays 180 ⁰C for the temperature of released gases in outlet pipe (instant t₅ in Fig 4). In order to avoid further rapid raise of the temperature of raw material and concurrent very intensive boiling, which during boiling process, according to the tests performed by the applicant, does not allow to create the necessary preconditions for obtaining required microstructure of coke, the temperature of the furnace 1200 is reduced starting from instant t₅ at a speed of 3-6 °C/min until this temperature drops into the range of 430-460 ⁰C (instant t₆ in Fig 4). This kind of a cyclic heating of the raw material allows to bring it very quickly up to the boiling temperature and at the same time to avoid overheating of the raw material upon starting of the boiling process.

For the time instant t₆ the raw material in cube reservoir has reached the temperature in the range of 330-350 ⁰C and boiling is going on with intensity that is needed in order to create in the raw material the necessary preconditions for obtaining required microstructure of coke. Starting from this moment the temperature of the furnace is smoothly raised at a speed of 0,1 -0,3 °C/min, ensuring an extra heat in the cube needed for boiling and also a practically linear raise of the temperature of the raw material into the range of 390-410 ⁰C. Vapours of lighter fractions released during boiling are removed from reservoir 1100 through outlet opening 1103 and the subsequent tubing.

Rising of the temperature of the furnace 1200 in the above described manner takes place until moment of time t₇ when foam starts forming in reservoir 1100, resulting in a rapid increase of temperature inside the reservoir 1100. Forming of foam indicates that the process of coke forming has started. In order to avoid possible infiltration of foam into the outlet piping raising of furnace temperature is still continued at the same speed (until instant t₈ in Fig 4), while starting from instant t₈ the temperature of furnace 1200 is raised at a speed of 5-7 °C/min for obtaining the heat required for coke formation until the temperature in reservoir 1100 starts to decrease (instant t₉ in Fig 4), evidencing that coking of the raw material has started. By the time the temperature of furnace 1200 has risen to 720-780 ⁰C, it is kept on the same level until the end of coking (forming of coke) and also during the following heating through of the coke. Coking of raw material ends when the temperature in reservoir 1100 after having decreased stabilizes (instant t₁₀ in Fig 4), heating through of coke lasts up to 2 hours and ends at instant t-n shown in Fig 4. After that annealing of coke takes place, for what purpose the burners in the furnace 1200 are closed and the temperature of the furnace 1200 starts to fall rapidly and prepared coke is annealed in reservoir 1100 for at least 2 hours using up the heat stored in the coke itself.

Annealing terminates at the instant indicated in Fig 4 by t-ι₂, after that the valve 1106 is opened and steam is introduced into reservoir 1100 in order to clean it from residual gases. The mixture of vapour and gases is led through opened valve 1104 into the unit 2000 for processing gaseous compounds. After that the coke is ready to be removed.

Processing and returning of the vapours-gases emerged in the process and of the used air takes place as follows.

From the mixture of gas and vapour led into the tank 2010 of the unit 2000 the heavy fractions (heavy distillate) condense already in that tank and this heavy distillate is led through outlet 2013 in the bottom of the tank 2010 into a special tank for its possible further use in the process. Lighter fractions, being still in a vapouhzed state, are led through outlet 2012 into first air cooler 2020, in which they are cooled to 140-150 ⁰C. At this temperature lighter fractions condense and this light distillate is led from the air cooler 2020 through outlet 2023 into the tank 3010 for light distillate of the unit 3000 for collecting and returning the processed residues, from where they by means of a pump 3030 are returned back into the process. The components (petrol, water and coke gas) staying gaseous at a temperature of 140-150 ⁰C are led through outlet 2022 into the inlet 2031 of the second air cooler 2030. In this air cooler the introduced gases are cooled to 10-40 ⁰C, condensed petrol and water are led through outlet 2033 into tank 3020 of the unit 3000 for collecting and returning processed residues, whereas coke gas is led out trough outlet 3032 and it can be used for heating of the coke cube. In the tank 3020 this mixture settles and petrol and water separate from each other. Petrol and water are returned into the process by means of the pump 3040. Using the same pump 3040 for returning both petrol and water anticipates using additional constructional solutions between the tank 3020 and the pump 3040, but as they are not essential in respect of present invention, they are not described in detail. They can be realized on the basis of the solutions already known from the prior art.

5 The described method for producing oil coke having improved microstructure, the microstructure being similar to the microstructure of acicular coke (needle coke) produced from petroleum and black coal, enables to produce oil coke, the microstructure index of which is at least 5,1 and the coke is in every way suitable for manufacturing of powerful electrodes used in chemical industry and metallurgy.

io The invention is not limited to the above described embodiment and covers all embodiments either directly covered by the claims and also their equivalent embodiments.

The list of reference numbers used in the figures

1000 - coke cube is 1100 - reservoir of coke cube 1101 , 1102 - inlets of coke cube

1103 - outlet of coke cube for gases and vapours

1104 - valve

1005 - thermocouple 20 1106, 1107 - valve

1108 - thermocouple

1200 - furnace of coke cube

1201 - wall of a furnace

1202 - opening 25 1203 - valve

1204 - bottom of a furnace

1205 - partition wall of a furnace 1206 - wall of a furnace

1207 - opening

1208 - thermocouple

2000 - unit for processing gaseous compounds 2010 - intermediate tank

2011 - inlet

2012 - outlet 2013- outlet 2020, 2030 - air cooler 2021,2031 -inlet

2022, 2032 - outlet

2023, 2033 - outlet

3000 - unit for collecting and returning processed residues

3010, 3020 -tank 3011,3021 -inlet 3012, 3022 -outlet 3030, 3040 - pump

3031,3041 -inlet

Claims

1. Method for producing of oil coke having improved microstructure, on the basis of shale oil, according to which the raw material is introduced into the coke cube and thereafter coked, for which purpose the raw material is heated until boiling temperature and boiled until forming of the coke bulk, the formed oil coke is heated through and further annealed and when annealing has been completed, the prepared oil coke is removed from the coke-cube, characterized in that

as a raw material a heavy fraction is used, having boiling temperature of 320 ⁰C and separated during coking process from a residual product of distilling of oil shale at atmospheric pressure and having boiling temperature of 350 ⁰C,

in order to start boiling the temperature of the raw material is raised to boiling point and during further boiling the temperature is smoothly raised to 390-410 ⁰C,

beginning of coking of the raw material is established by the start of foam release in the coke cube,

after the start of coking of the raw material the furnace temperature is raised to 720-780 ⁰C and said temperature is maintained until the end of heating through of the formed coke.

2. Method for producing of oil coke having improved microstructure, on the basis of shale oil, according to claim 1 , characterized in that for rising the temperature of raw material to boiling temperature, the temperature of furnace is raised at a speed of 3-6 °C/min to the temperature of 680-720 ⁰C until the start of release of light fractions, thereafter the temperature of the furnace is reduced to 430-460 ⁰C at a speed of 3-6 °C/min.

3. Method for producing of oil coke having improved microstructure, on the basis of shale oil, according to claim 1 , characterized in that smooth raising of the temperature of raw material is effected during the whole boiling period.

4. Method for producing of oil coke having improved microstructure, on the basis of shale oil, according to claim 1 , characterized in that for raising of the temperature of raw material continuously during boiling the temperature of the furnace is steadily raised starting from 430-460 ⁰C until the coking of raw material starts.

5. Method for producing of oil coke having improved microstructure, on the basis of shale oil, according to claim 1 , characterized in that the temperature of the raw material introduced into cube is at least 180 ⁰C.