RU2372374C1 - Processing method of black oil fuel and installation for its implementation - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: inventions relates to oil processing, particularly to delayed coking and viscosity breaking of black oil fuels. Method includes preheating of initial raw material in heat exchangers, heating of initial raw material in tube kiln, mixing of initial raw material with recirculating delay line with formation of secondary raw material. Secondary raw material is heated up to temperature of decomposition starting in radiant coil pipe of tube kiln. Following heating up to specified temperature of treatment process is implemented in cooled outside sectional transfer pipeline, leading into reactor, by means of mixing with preheated air-steam mixture in amount 1 -12 % on raw material. Air-steam mixture is supplied evenly by length of sectional transfer pipeline. Processing products from reactor is directed into rectifying column. Installation includes heat exchangers, furnace for raw material heating, connected to reactor by sectional transfer pipeline and rectifying column. Each section of transfer pipeline is connection to line of input of air-steam mixture and is outfitted by cooling jacket, connected to line of delivery of gas oil-refrigerant from rectifying column. Installation additionally contains kiln for heating of air-steam mixture and tank for mixing of initial raw material with gas oil-recirculator.

EFFECT: inventions are directed to reduction of coke sedimentation in coil pipe of kiln and in transfer pipeline with simultaneous increasing of raw material conversion.

9 cl, 3 tbl, 2 dwg

Description

The invention relates to the refining industry and can be used for the processing of heavy oil residues by delayed coking or visbreaking

A known method of processing oil residues by delayed coking or visbreaking (S.A. Akhmetov. Technology for the deep processing of oil and gas. - Ufa: Guillem, 2002, pp. 378-389) by heating the raw materials in heat exchangers, convection coil of the furnace, contact with recycled cracking products with the formation of secondary raw materials, subsequent heating in a radiant coil of the furnace and feeding into the reactor to increase the conversion of raw materials to a predetermined value with the production of delayed coking (UZK) 70-80% of gas and distillate and 20-30% of coke and setting kebreaking (UVB) - 18-40% of gas and distillate and 60-82% of boiler fuel.

Installation for implementing the method includes heat exchangers, a furnace for heating raw materials, a reactor and a distillation column. The supply of heated raw materials to the reactor is carried out through a transfer pipeline.

A disadvantage of the known method and installation is that during the processing of heavy oil residues, the furnace coil, transfer pipeline, and visbreaking reactor at UVB quickly coke and additional operational and capital costs are required to restore the operability of the equipment.

Closest to the proposed method, according to the essential features, is a method for processing heavy oil residues to produce petroleum coke, including preheating the raw materials in heat exchangers, a convective coil of a tubular furnace, mixing with recirculate, subsequent heating of the secondary raw materials in the radiant coil of the furnace to the coking temperature and feeding by transfer piping into the coking reactor.

A feature of the method is the air supply to the recirculate or to a mixture of raw materials with recirculate in an amount of 2-9% for raw materials (US Pat. RF No. 2067605, op. 10.10.96, BI No. 28).

The known installation consists of standard equipment, which includes heat exchangers, a furnace for heating raw materials, a reactor with a transfer pipeline and a distillation column.

A disadvantage of the known method and installation is also that with the weighting of the feedstock, the risk of coking of the furnace coil and transfer pipeline increases if it is necessary to increase the conversion of raw materials, which entails a reduction in the duration of the installation and an increase in operating and capital costs, as well as the inability to process such heavy residues as refinery waste.

The technical result to which the invention is directed is to reduce the coking of the furnace coil and the transfer pipeline while increasing the conversion of raw materials.

The specified technical result is achieved by the fact that in the method of processing heavy oil residues, including preheating the primary feedstock in heat exchangers, heating the primary feedstock in a tube furnace, mixing the primary feedstock with recycle to form secondary feedstock, heating the secondary feedstock to a decomposition temperature and further heating to a predetermined the temperature of the processing process in the presence of a gaseous additive and feeding into the reactor, followed by separation of the processed products in a distillation column, with According to the invention, the secondary raw materials are fed into the reactor through a sectional transfer pipeline, the secondary raw materials are heated to the decomposition onset temperature of 420-450 ° C in a radiant coil of the tube furnace, and the heating to a predetermined temperature of the processing process is carried out in a sectional transfer pipeline that is cooled outside by mixing with gaseous additive, which is used as a preheated steam-air mixture in an amount of 1-12% for raw materials, which are served uniformly along the length of the section transfer tube plumbing.

Sectional transfer pipeline, it is advisable to cool the circulating gas oil from the distillation column with a temperature of not more than 160 ° C.

The vapor content in the vapor-air mixture may be 10-50% by volume per mixture.

It is advisable to increase the temperature of the raw material along the length of the sectional transfer pipeline evenly from the initial one at the inlet to the pipeline to the desired temperature for introducing the raw material into the reactor.

Also, the above technical result is achieved by the fact that in the installation for processing heavy oil residues, including heat exchangers, a furnace for heating raw materials connected to the reactor by a transfer pipeline, and a distillation column, according to the invention, the furnace for heating raw materials is connected to the reactor by means of a section transfer pipeline, each section which is connected to the steam-air mixture inlet line and provided with a cooling jacket in communication with the supply line of gas oil-refrigerant from the distillation column, while the apparatus further comprises a furnace for heating the vapor mixture and the container for mixing the primary raw material with a gas oil-recirculate.

The cooling jacket of the transfer pipeline section can be made with lens compensators.

A pneumatic shut-off valve can be placed on the pipe for introducing the air-vapor mixture into the transfer pipeline section.

The transfer piping section may be provided with a thermocouple.

The tank for mixing primary raw materials with gas oil recycle can be equipped with a circulation system and is made in accordance with the invention according to US Pat. RF №2282657.

Heating of the secondary raw material to its decomposition temperature in the radiant coil of the furnace (420-450 ° C) allows to reduce the heat load on the furnace and thereby reduce the risk of coking and increase the duration of operation.

Heating the feedstock to a predetermined temperature of the process for processing oil residues - coking (480-530 ° C) or visbreaking (460-500 ° C) in a sectional transfer pipeline with a cooling jacket in the presence of a vapor-air mixture supplied uniformly at several points of the pipeline, ensures quiet controlled conduct exothermic process in the pipeline in the regime of smokeless oxidation of raw materials and direct heat and mass transfer between oxidation products and raw materials, allowing heating to a given temperature of the processing process in the volume of the reaction mass flow, which eliminates the formation of coke deposits on the inner surface of the transfer pipeline. In addition, the proposed process mode allows you to control the conversion of raw materials and promotes the formation of a protective layer of solidified solid hydrocarbons (such as asphaltenes) on the inner surface of the transfer pipeline that is cooled outside, which reduces the risk of coking of the pipeline and increases the length of the overhaul run to the planned standards for ZK and VB installations.

Also, the proposed technology allows one unit to be used both for the delayed coking process and for the visbreaking process, i.e. has versatility.

The analysis of the proposed technical solution for novelty showed the presence of new conditions for the implementation of the actions in the method (heating of secondary raw materials to the temperature of their decomposition in the radiant coil of the furnace and heating of raw materials to a given temperature of the processing process in a transfer pipeline cooled by transfer) and a new form of the element in the device (transfer pipeline with a cooling jacket), i.e. the proposed method and installation meet the condition of patentability "novelty."

A search by distinguishing features revealed a method for processing heavy oil residues - visbreaking, including heating the oil residue to visbreaking temperature (450-485 ° С), holding visbreaking products in an adiabatic reactor to produce gas, gasoline fractions and visbreaking residue, while the reactor is made tubular at the ratio of the length of the tubular reactor to a diameter of more than 200 (US Pat. RF No. 2272063, op. March 20, 2006 BI No. 8).

In the known method, the visbreaking process is carried out in a tubular reactor similarly to carrying out the proposed method in a transfer pipeline and the known invention is also aimed at reducing the coking of the reactor. This problem is solved in the known invention by increasing the flow velocity due to the small cross section of the reactor pipe.

In the proposed inventions, the same problem is solved by cooling the walls of the reactor - transfer pipeline, which allows to achieve a new technical result - the creation on the inner wall of the transfer pipeline (tubular reactor) of a protective film of solidified solid hydrocarbons, which prevents coke deposition and steam-air mixture supply, which is even more effectively solves the problem of reducing coking of the reactor. Thus, the proposed invention meets the condition of patentability "inventive step"

Figure 1 shows the installation for implementing the proposed method, where 1 is the mixing tank of primary raw materials with gas oil-recycle, 2 is a circulation system, 3 is a heating furnace with convective 4 and radiant 5 coils, 6 is a furnace for heating a steam-air mixture, 7 - a sectional transfer pipeline with a cooling jacket 8, 9 - a reactor with a conical part 10, 11 distillation column, 12 - a heat exchanger-cooler, 13 - a supply line of primary raw materials, 14 - a supply line of gas oil-recycle, 15 - a supply line of secondary raw materials, 16 - steam manifold air mixture into the transfer pipeline, 17 — a manifold for supplying gas oil-refrigerant to the jacket of the transfer pipeline, 18, 19 — lines for introducing air and chemically purified water into the furnace 6, 20 — a helmeted pipeline, 21 — a line for discharging gas oil-refrigerant from the distillation column, 22 - line for the discharge of gas, gasoline and water vapors, 23, 24, 25 - lines for the output of light gas oil, recycle gas oil and bottoms, respectively, 26, 27, 28 - lines for introducing chilled products into the distillation column 11, 29 - water supply line to the heat exchanger-refrigerator.

Figure 2 shows the sectional section of the transfer pipeline section, where 30 is the lens compensator of the cooling jacket 8, 31, 32 is the inlet and outlet pipes of the gas oil refrigerant, 33, 34 are flange connections, 35 is a pneumatic shut-off valve, 36 is a check valve , 37 - thermocouple, 38 - filter for steam-air mixture.

The proposed method is as follows (figure 1). The feedstock 13 is preheated in heat exchangers (not shown), the convective coil 4 of the furnace 3 to a temperature of 350-380 ° C and fed together with the gas oil-recirculate 14 into the tank 1, where they are mixed by the circulation system 2. The secondary feedstock 15 is fed through a radiant coil 5 furnace 3, where it is heated to 420-450 ° С - the temperature at which decomposition of raw materials begins, into the transfer pipe section 7 with a cooling jacket 8, where in the presence of a steam-air mixture supplied through collector 16, it is heated to a coking temperature of 485-530 ° С ( if the process Flax to distillates or coke) or visbreaking temperature 460-500 ° C (if the process is directed to the production of fuel oil) and then - in the conical part 10 of the reactor 9.

Air 18 and chemically purified water 19 in a predetermined ratio are heated in the coil of the furnace 6 and served as a steam-air mixture through a manifold 16 in a section of the transfer pipeline 7 cooled outside. The amount of steam-air mixture (1-12%) is controlled according to a given temperature of the product in a specific section of the cooled transfer pipeline or conical part of the reactor, providing a uniform temperature rise of not more than 50 ° C per hour.

In the reactor 9, due to the accumulated heat and additional heat supply during oxygen oxidation of a part of the feedstock, the thermodestructive process of cracking the feedstock continues with the formation of gas, gasoline, light and heavy gas oils, coke or boiler fuel. During delayed coking, the coke cake remains in the reactor, and the remaining products leave the reactor and through the helmeted pipe 20 enter the distillation column 11 for separation by components. When visbreaking, the cracked products in the liquid phase also through the helmet pipe 20 enter the column 11 for separation.

Gas, gasoline and water vapors 22 are taken from the top of the column 11, gas oil 23 at the side, heavy gas oil 24, gas oil recycle 14, bottoms gas - a component of boiler fuel 25, gas oil-refrigerant 21, and some chilled products 26, 27, 28 for ensure the rectification process is returned to the column.

Gas oil 21, used as a refrigerant, is removed from the column 11, cooled by water 29 in a heat exchanger-refrigerator 12 to a temperature of not more than 160 ° C and sent in parallel flows through the collector 17 to the cooling jackets of 8 sections of the transfer pipeline, and then returned to the column 11. The supply of refrigerant is synchronized with the supply of steam-air mixture in the same section and when the collector 16 of the steam-air mixture is turned off, the flow of refrigerant to the cooling jacket 8 is stopped.

The phase composition of the reaction mixture is determined by its height, pressure drop, analysis of the liquid phase from the bottom of the column when water vapor or nitrogen is introduced into the reactor and this stream exits from it. The disappearance of the pressure drop indicates the formation of a coke cake. After steaming and cooling the coke cake, the upper and lower hatches of the reactor are opened and coke is hydraulically discharged to the adjacent site. After sampling and analysis of coke, the technological mode of the next coking cycle is adjusted.

The visbreaking process is regulated by the minimum viscosity of the bottom residue 25 from the bottom of the column 11.

Section cooled transfer pipeline works as follows. The stream of secondary raw materials through the flange 33 enters the first section of the transfer pipeline, where the air-steam mixture in a predetermined quantity is introduced through the hole of the pneumatic shut-off valve 35 through line 16. In the presence of a vapor-air mixture, a smokeless exothermic process of oxidation of a part of the feed occurs and the flow temperature rises to a predetermined value for this section, the amount of the steam-air mixture is controlled by the flow temperature at the outlet of the section, which is measured with thermocouple 37. Gas oil-refrigerant with a temperature of not more than 160 ° C enters the jacket 8 through the pipe 31, leaves heated through the pipe 32 and then into the column 11.

The following are examples of the implementation of the proposed method in laboratory conditions, where table 1 presents the proposed method aimed at obtaining products of delayed coking, table 2 shows the known prototype method, table 3 shows the proposed method aimed at producing visbreaking products.

As a raw material used tar with a density of 998 kg / m ³ , coking ability of 13%, conditional viscosity at 80 ° C - 250. Recycle - heavy gas oil (with a density of 850 kg / m ³ , coking ability of 0.3%) was taken only in the known method for preparation recyclable materials with a recycling ratio (Cr) of 1.2. In the proposed method, Kr = 1.0.

The laboratory installation includes a raw and starting tank, a furnace and transfer pipeline loading pump, a water pump, a rotameter for measuring air flow, a furnace for high-temperature heating of raw materials and steam-air mixture, a transfer pipeline from the furnace to the reactor, a coking or visbreaking reactor, and a pressure control valve at the outlet of the furnace and reactor, a distillate condenser-refrigerator, a distillate separator-receiver, a gas clock, electrical equipment and measuring instruments.

The end of the experiment was determined by increasing the pressure at the inlet to the furnace for heating the raw materials and air-vapor mixture by 25% of the initial value. The initial pressure at the inlet to the feed furnace was 2 MPa, at the inlet to the transfer pipeline was equal to the pressure in the reactor - 0.2 MPa. The beginning and end of the coking or visbreaking stage in the reactor was determined by the dynamics of the receipt of the process products — distillate and gas, respectively, into the receiver-separator and gas clock.

Experiments on the duration of the path of the raw furnace — transfer pipeline and coking and visbreaking in the reactor for the known method were done separately. At the end of the experiment, a material balance was made, furnace coils were inspected, coking or visbreaking products were taken for analysis. Analyzes of raw materials and products of coking and visbreaking were carried out according to well-known methods adopted in oil refining.

From tables 1, 2, 3 it can be seen that the duration of the run of the raw furnace and transfer pipeline by the proposed method for processing heavy oil residues exceeds the known method by 60-80%. In addition, according to the proposed method, by controlling the flow rate and composition of the vapor-air mixture, it is possible to control the duration of the coking stage, in particular, reduce the coking time by a monolithic and by a factor of 2.5-4.3 when the granular state of the coke cake is preserved while maintaining the value the volatiles content in the coke cake in both cases is not higher than in the known method (5.5 <7.2; 4 <7.2). Moreover, in the proposed method, it is possible to increase the yield of distillate by 7-14.6% for raw materials, to reduce the yield of coke by 9-13% for raw materials. Upon receipt of a granular coke cake, it can be used as fuel,

According to the proposed visbreaking method, it is possible to obtain 83-90% for raw materials of boiler fuel of grade M 100 with a conditional viscosity at 80 ° C of less than 16 ° E and raw material distillates for the production of motor fuels.

Thus, the proposed method and installation can increase the length of the run of the coil of the furnace by more than 60%, reduce the duration of the coking stage by 2.5-6 times without increasing the content of volatile substances in it, increase the yield of coking distillate by 7-14.6% by raw materials, reduce the coke yield by 9-13% for raw materials, and when processing according to the visbreaking option, get boiler fuel and raw materials for the production of motor fuels.

In addition, the proposed inventions are universal, as they can be implemented in one installation for the processing of heavy oil residues both for the production of petroleum coke or distillates, and for the production of boiler fuel.

Another advantage of the proposed inventions is the possibility of recycling oil refinery waste, such as, for example, oil sludge and asphalt, which allows expanding the raw materials for the production of motor fuels and solving environmental problems associated with the reduction of oil waste contaminated with mechanical impurities.

Claims (9)

1. A method of processing heavy oil residues, including preheating primary raw materials in heat exchangers, heating primary raw materials in a tube furnace, mixing primary raw materials with recycle to form secondary raw materials, heating secondary raw materials to a decomposition temperature and further heating to a predetermined processing temperature in the presence of gaseous additives and feeding into the reactor with subsequent separation of the processed products in a distillation column, characterized in that the supply of secondary raw materials to the reactor is about exist through a sectional transfer pipeline, heating of secondary raw materials to the decomposition onset temperature of 420-450 ° C is carried out in a radiant coil of a tube furnace, and heating to a predetermined temperature of the processing process is carried out in a sectional transfer pipeline that is cooled outside by mixing with a gaseous additive, which is used previously heated steam-air mixture in an amount of 1-12% for raw materials, which are fed uniformly along the length of the section transfer pipeline. 2. The method according to claim 1, characterized in that the sectional transfer pipeline is cooled by a gas oil-refrigerant from a distillation column with a temperature of not more than 160 ° C. 3. The method according to claim 1, characterized in that the vapor content in the vapor-air mixture is 10-50 vol.% Per mixture. 4. The method according to claim 1, characterized in that the temperature of the raw material along the length of the sectional transfer pipeline is increased evenly from the initial temperature at the inlet to the pipeline to a predetermined temperature for introducing the raw material into the reactor. 5. Installation for processing heavy oil residues, including heat exchangers, a furnace for heating raw materials connected to the reactor by a transfer pipeline and a distillation column, characterized in that the furnace for heating raw materials is connected to the reactor using a sectional transfer pipeline, each section of which is connected to the steam-air input line mixture and equipped with a cooling jacket in communication with the supply line of gas oil-refrigerant from the distillation column, while the installation further comprises a furnace for heating steam-air minutes and a mixture of the primary container for mixing with the gas oil feedstock, recirculate. 6. Installation according to claim 5, characterized in that the cooling jacket of the transfer pipeline section is made with lens compensators. 7. Installation according to claim 5, characterized in that a pneumatic shut-off valve is placed on the pipe for introducing the air-vapor mixture into the transfer pipeline section. 8. Installation according to claim 5, characterized in that the section of the transfer pipeline is equipped with a thermocouple. 9. Installation according to claim 5, characterized in that the tank for mixing primary raw materials with gas oil-recycle is equipped with a circulation system.

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