RU2697465C2 - Design of reaction-rectification apparatus of periodic action for performance of thermo-catalytic processes - Google Patents

Abstract

FIELD: oil industry.SUBSTANCE: invention relates to designs of mass-exchange apparatus of periodic action and can be used in oil refining and petrochemical industry. Reaction-rectification apparatus includes a reaction vat fraction and a reaction-fractionating column with catalyst attachments connected to it by means of detachable connection. Each nozzle section is made of stainless steel, and tubular capacitors are connected to it by means of nozzles for selection of light oil fractions. Heat-sensitive elements are arranged opposite the capacitors to fix thermodynamic parameters in the catalytic section. In the reaction-rectification column the plate contact devices on which the catalyst nozzles are laid are alternated through metal spacers with empty plates for condensation of vapours formed on the surface. Reforming and isomerisation processes are carried out on the surface of the solid-phase catalyst nozzle, and a reforming process takes place in the bottom part in the presence of a solid-phase catalyst.EFFECT: increased degree of conversion of initial hydrocarbons of oil and increased selectivity of target products, as a result of which depth of oil refining is increased.1 cl, 5 dwg, 5 tbl, 3 ex

Description

Usage: the invention relates to the design of apparatus for oil refining and can be used to upgrade atmospheric or vacuum distillation of oil.

Technical task: improving the efficiency of oil refining.

The inventive design of a reactive distillation apparatus of periodic action, when used for oil processing, combines the processes of its fractionation and catalytic cracking in the liquid phase in the presence of ultrafine metal catalysts and catalytic reforming and isomerization of the obtained light fraction in the gas phase, on the surface of the catalyst placed in the nozzle of the distillation column.

The invention relates to the construction of mass-exchangers of periodic action in the oil refining and petrochemical industries. It can be used to study and simulate the processes of catalytic cracking of oil and heavy hydrocarbons in the liquid phase, processes of catalytic reforming and isomerization of light fuel fractions in the gas phase on the surface of a solid catalyst.

Known for patent EA 201491445 A1 is a device for carrying out chemical reactions in which one starting substance is in the liquid phase and one product is in the gas phase, containing a reaction zone, which includes two catalytic sections, each section having a feed channel and an overflow pocket , which simultaneously serves as a supply channel for the next section, so that fluid from each section enters the overflow pocket of this section and through it enters the lower part of the next section, and the device neno with the ability to divert the gaseous products of each section, bypassing the remaining sections

The disadvantage of the above device is that this design can only be effectively used to produce individual hydrocarbons.

A device for carrying out chemical reactions over a fixed catalyst bed, in which the starting material is in the liquid phase, is known in the patent US 20150086430, the product is in the gas phase, including the reaction zone, which includes two catalytic sections located one below the other, each section has a feed channel and a bypass pocket, which simultaneously acts as a feed channel for the next section in the direction of fluid flow, so that the liquid from each section passes into the overflow pocket th sections and through it enters the bottom of the next section.

The device contains several catalytic zones, each of which has its own supply and gas channels, which complicates the technical design of this design.

The closest in design to the proposed invention is a distillation module of low productivity, described in RF patent No. 47875. A distillation module is a set of elements - a still part, a packing column, a reflux condenser connected by quick disconnect connections.

The packing column is made using curly copper nozzles, on the surface of which light vapor vapor is condensed, as a result of which the evaporated liquid is condensed and enriched with high-boiling components, the gas phase condensed in the reflux condenser is low-boiling. Thus, the adjustable number of theoretical - distillation plates reaches rather high values. Using this distillation module, the process of rectification of multicomponent mixtures is carried out. Belongs to a class of columns of periodic action.

The disadvantage of this installation, despite the simplicity and convenience of the design, is the low range of permissible operating temperatures (up to 250 ° C), which limits its scope, the lack of fittings for thermocouples along the height of the nozzle does not allow you to control the change in temperature parameters of the rectification process.

The aim of the invention is to combine the processes of oil fractionation with its thermocatalytic destruction in the presence of ultrafine metal catalysts introduced into the liquid phase with the process of catalytic reforming in the gas phase of the obtained fraction in the presence of solid phase catalysts.

The goal is achieved:

A) the organization of the first reaction zone in the distillation column cube;

B) organization of the height of the distillation column of the second reaction zone with the placement of solid-phase catalyst on perforated plates. The following design is proposed.

The device comprises a housing, the bottom, bottom, part of which is made of stainless steel and has a forged elliptical bottom, a flat cover, a neck connected by a threaded connection to a distillation column made in the form of a cylindrical shell with contact devices (plates and nozzle) placed in it .

Tubular capacitors are connected to each packed section of the column by means of fittings for the selection of narrow light oil fractions and heat-sensitive elements, which allow recording the temperature change along the height of the column.

The column sections are separated by steel plates located on steel spacers made in the form of thin-walled cylinders of small height. The plates have longitudinal openings similar to the design of a failure-type mass transfer plates, providing the required live section of the column for the passage of the gas phase.

The catalyst is placed on the plates, forming a nozzle of a certain height. The packed sections alternate with empty plates made of the type of plates of a failure type, which ensures condensation of the ascending vapors and their return to the catalyst nozzle, which increases the degree of conversion of the starting material due to its multiple contact with the catalyst and, as a result, increases the selectivity of the target products .

The upper part of the column is connected by means of a threaded outlet to a tubular condenser, through which at the initial stage of the sublimation process gases with a low carbon content - C1-C3 are vented, which stabilizes the chemical and fractional composition of the product.

Thus, mass transfer is organized on the contact devices, combined with the catalytic process of converting the chemical composition of light oil fractions on the catalyst surface. Sectioning the nozzle and the ability to measure the temperature in each nozzle section makes it possible to fix the thermodynamic parameters of the reforming process of light oil fractions in the study of various catalysts.

The detachable connections of the structural elements of the distillation unit allow replacement of the catalysts without any particular difficulties.

A device is shown (Fig. 1), containing a cube part 1 made of stainless steel, in which there are fittings for a thermometer 2 and for a manometer 3, a distillation column 5, which is a cylindrical shell made of stainless steel, with contact devices placed in it, connected by a threaded connection to the bottom part with a union nut 4.

On the cylindrical shell there are three “pipe in pipe” type condensers 6, mounted relative to each other at an angle of 120 ° in the horizontal plane (section section - see Fig. 3), designed for selection and condensation of light hydrocarbon fractions in packed sections of the distillation column.

Fittings 7 are used to enter the coolant, fittings 8 are used to drain it from the condenser jacket.

The upper part of the distillation column by means of a steeply curved outlet 9 containing a fitting 10 for installing a thermometer is connected to a capacitor 11 made in the form of a “pipe in pipe”.

Distillation installation works as follows.

A certain amount of oil is poured through the neck into the bottom part. In the fittings 2 and 3, located on the lid of the cube, are sensors for measuring temperature and pressure. The bottom part is placed in the mantle, the heating elements of which are made in the form of tubes twisted into a spiral, repeating the configuration of the bottom of the bottom part. The neck of the bottoms by means of a threaded connection and a union nut 4 is connected to the distillation column.

Packed sections are organized as follows.

In the lower part of the shell of the distillation column 1 (Fig. 2), a steel support ring 2 is welded from the inside, onto which a steel disk 3 with longitudinal holes is laid, the appearance of the disk is shown in FIG. 3. Next, a steel ring 4 is placed in the distillation column, resting on a similar disk 3 and a steel spacer.

In the cavity formed by the ring 4 and the spacer, the catalyst is pushed in or regularly loaded, which is covered with the next steel disk, supported by the spacer. Similarly, through the steel spacers in the column is placed an empty mass transfer plate 5, which is a steel disk with holes that form a living section of a distillation column. Similarly, the remaining packed sections of the column are assembled.

In the fittings of the sections of the distillation column are the input tubes of capacitors and thermocouples. The fittings on the condenser shirts are connected to the liquid cooling system. As a cooling agent can be used running tap water, or refrigerants flowing laboratory cooling systems (antifreeze, deg, etc.).

Using a threaded connection to the upper part of the column, a branch is connected where the thermally sensitive element is located. The outlet is threadedly connected to the condenser, the fittings on the jacket of which are connected to the cooling system.

Condenser pipes are connected by elastic tubes to reservoirs of receivers of oil fractions — products of a stepwise catalytic refinement of a gasoline fraction with varying degrees of conversion of the starting material.

The separation of the hydrocarbon mixture and their chemical conversion in the presence of a catalyst takes place in a cylindrical shell on the contact devices mounted in it, which are in general a plate of a failure type (Fig. 5).

Condensing liquid on the contact devices, flowing down, is in contact with rising upward pairs of hydrocarbons formed during the boiling of oil, or of narrow oil fractions in the bottom part. A part of the obtained light fraction, condensing, flows downward, mixing with the boiling starting fraction, and again participates in the chemical conversion on the catalyst surface, which increases the degree of conversion of the feedstock and ensures stabilization of the chemical and fractional compositions of the product.

The catalytic packing device and the process of passing the gas phase through the packing layer are shown in FIG. 3.

A vapor-liquid layer of intense mass transfer is formed on the contact devices. A catalytic interaction of the components of the vapor-liquid mixture on the surface of the solid catalyst occurs in the packed bed.

Capacitors mounted in a cylindrical shell of a distillation column are used as a device for sampling fractions that are products of the catalytic conversion of a gaseous product in each individual section. Obtaining narrow fractions allows us to study the change in the chemical composition of the fraction and the kinetic characteristics of the process in three cycles of its interaction with the catalyst located in the packed section. The temperature measurement in the packed section allows you to determine the thermodynamic parameters of the reaction (Fig. 4).

Example 1. At the presented facility, the Kharyaginskoye field oil was distilled, the physicochemical characteristics of which are presented in Table 1.

Table 1. Physico-chemical characteristics of the oil Kharyaga field (well 7, wellhead 2)

During distillation, the following were introduced into the oil: ground zeolite and catalysts in nanostructured form in the form of a suspension in straight-run naphtha. As a catalyst, a mixture of nanostructured Ni particles with a size of 15-50 nm, Cr 15-50 nm, Mn 15-50 nm in an amount of 0.1% by weight of the taken raw material was used.

The acceleration in order to extract the gasoline fraction boiling in the temperature range from 32 to 195 ° C was carried out as follows:

250 ml of oil was taken for distillation. The mixture of metal particles was calcined in a muffle furnace and added to 50 ml of straight-run gasoline. The resulting suspension was introduced into the oil.

After the suspension was introduced, the oil was mixed with a paddle mixer. The resulting mixture was poured into a cube distillation unit.

A distillation column is connected to the neck of the bottom part of the installation by means of a threaded connection and a union nut.

Through the free end of the column, a steel spacer is inserted into the tube, which is a cylinder, on the end surface of which a mass transfer plate is laid, on the plane of which a larger spacer is installed. 5 grams of zeolite in the form of cylinders obtained by extrusion modified with nanostructured platinum with a particle size of 15-50 nm is poured onto a plate.

The average length of the cylinders is 10 mm, the diameter is 1.8 mm. The height of the zeolite layer obtained in the nozzle is 13 mm. Further along the height of the column is the next mass transfer plate, behind which an empty mass transfer plate is installed through a spacer of low height.

Along the perimeter of the empty mass transfer plate, the next spacer of low height and the mass transfer plate, on which 5 grams of zeolite, are also placed. The strength coefficient of the catalyst is approximately 1 kg / mm, which allows its multiple use. The bulk density of 0.8 grams / cm ³ . Next, the assembly sequence is repeated, resulting in three packed sections in between which there are mass transfer plates, due to the condensation of the vapors of low boiling hydrocarbons rising upwards, the condensed vapor phase is recycled to them.

Along the height of the distillation column there are paired openings equipped with fittings for connecting capacitors of the “pipe in pipe” type, by means of which the products of oil fractionation are removed and the fittings for thermometers providing temperature control over the height of the column.

The free end of each capacitor is connected with an elastic tube to the product receiver flask. The refrigerant is introduced into the external tube of the condenser, the discharge of which is also provided by means of a fitting located on the external tube.

Thus, continuous circulation of the refrigerant in the jacket of the condenser is carried out, which allows you to maintain optimal temperature parameters of the condensation process.

An A-40D brand antifreeze containing ethylene glycol, water and a complex of anti-corrosion additives is used as a refrigerant. The temperature of the antifreeze condenser supplied to the jacket is regulated by an LT-300 cryostat. The required temperature is set using the control panel located on the cryostat housing.

The cryostat is equipped with a pump that provides continuous circulation of the refrigerant in the heat exchange circuit, as well as a device for measuring its temperature. The upper part of the distillation column using a threaded connection and a union nut is connected to the fitting for installing the thermometer. The free end of the outlet with a threaded connection and a union nut is connected to a capacitor, such as "pipe in pipe". The pipe of each capacitor is connected with an elastic tube to the receiver-receiver of light fractions. The design using metal holders is mounted on a tripod, on the basis of which a heating mantle is placed, the winding of the heating spiral of which repeats the configuration of the bottom of the distillation unit distillation unit, which allows for uniform heating of the medium in the unit of the distillation unit.

At the end of the assembly and placement of the distillation unit, all associated electrical appliances are included in the electrical network in the following sequence: mantle heater, cryostat and gradually begin to heat the contents of the cube. The temperature of the mantle is increased at a rate of 4 degrees per minute until the vapor temperature reaches 195 ° C and the last drop of condensing vapor phase expires.

Vaporization in the process of oil distillation begins when the temperature reaches 34 ° C. At this time, together with the vapors of liquid low-boiling hydrocarbons, associated gases adsorbed on heavier hydrocarbon molecules begin to escape during the destruction of gas associates due to a decrease in the density of oil with an increase in its temperature.

During the process of distillation, temperature and pressure are recorded in the cubic part of the installation and along the height of the column.

At the points of location of the particles of the nanostructured catalyst in the liquid phase, boiling centers are formed in the cube of the column due to their overheating.

The selection of the target fraction boiling in the temperature range from 34 to 195 ° C for a specific raw material is carried out from the upper section of the distillation column. The temperature in the bottom of the column varies in the range from 20 to 250 ° C.

The vaporous phase of hydrocarbons rises to the top of the distillation column, where it interacts with a nozzle, which is a layer of zeolite laid in bulk. Some of the vapors condense and drain onto the underlying mass transfer plates, where the vapors are enriched with low boiling hydrocarbons, and liquids with high boiling ones.

With stable parameters of the catalytic zones and stability of the characteristics of the raw materials, a stable reproducibility of the results is observed.

In the case of a slight deviation of the fractional composition (a change in the temperature of the end of boiling due to an increase or decrease in pressure, a change in the ambient temperature), the process is controlled by changing the amount of heat supplied to the heating of the bottom part of the column and increasing the thickness of the thermal insulation of the distillation column. The process parameters, the consumption of raw materials and catalyst are shown in table 2.

Table 2. Parameters of the process of oil distillation and characteristics of the catalyst

The obtained straight-run gasoline fraction was subjected to chromatographic analysis using a Crystal 5000.2 gas chromatograph.

Example 2. The distillation process was carried out analogously to example 1 with the difference that nanostructured W particles with the addition of tungsten (III) oxide powder - W ₂ O _{3 were} used as catalysts introduced into the liquid phase, and steel spiral prismatic rings were placed in the catalytic nozzle (hereinafter referred to as SEC) with deposited Re in nanostructured form.

The proportion of the introduced masses of oil and straight-run naphtha for the preparation of the catalyst suspension remained the same.

The process parameters, the consumption of raw materials and catalyst are shown in table 3.

Table 3. Parameters of the oil distillation process and catalyst characteristics

Example 3. The distillation process was carried out analogously to example 1 in the presented distillation plant with the difference that nanostructured Ti particles with the addition of titanium oxide particles (Ti) ₂ and TiO _{2 were} used as catalysts introduced into the liquid phase, and a cubic shape foam metal was placed in the catalytic nozzle based on copper, having an open porous structure.

The proportion of the introduced masses of oil and straight-run naphtha for the preparation of the catalyst suspension remained the same.

The process parameters, the consumption of raw materials and catalyst are shown in table 4.

Table 4. Parameters of the process of oil distillation and characteristics of the catalyst

The distillation of oil upon introduction into the liquid phase of a suspension of finely dispersed particles of metal and metal oxides in a nanostructured form makes it possible to increase the yield of the gasoline fraction. The organization of the contact of the obtained gasoline fraction in the gas phase on the surface of aggregated catalysts modified with metals in nanostructured form makes it possible to increase its octane number as a result of isomerization and reforming processes.

Qualitative characteristics of the obtained gasoline fraction are shown in table 5.

Table 5. Data on the mass yield and quality characteristics of the gasoline fraction

Claims (1)

The design of a batch reactive distillation apparatus for carrying out heterogeneous thermocatalytic processes, including a still bottom part and a reactive distillation column with catalyst nozzles articulated with a detachable connection, characterized in that each tubular section made of stainless steel is made up of tubular fittings by screwing condensers for the selection of light oil fractions and heat-sensitive elements located opposite them for I fix the thermodynamic parameters in the catalytic section during the study of various catalysts, and the catalyst sections of the column, separated by plate contact devices on which the catalyst nozzles are laid, are alternated by joining through metal spacers with empty plates to condense the oil formed during cracking in the bottom part in the presence of solid-phase catalyst for ascending vapors and returning them to the solid-state catalyst packing section, on the surface of which tvlyayutsya reforming and isomerization processes that provides increased degree of conversion of the hydrocarbon oil and increase the selectivity of products, thereby increasing the depth of refining.

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