WO2007086774A1

WO2007086774A1 - Method for distilling a hydrocarbon material and a plant for carrying out said method

Info

Publication number: WO2007086774A1
Application number: PCT/RU2006/000370
Authority: WO
Inventors: Yuri Vladimirovich Feschenko
Original assignee: Yuri Vladimirovich Feschenko
Priority date: 2006-01-24
Filing date: 2006-07-12
Publication date: 2007-08-02
Also published as: RU2301250C1; CN101360807B; EA010729B1; CN101360807A; EA200801088A1

Abstract

The inventive method for distilling a hydrocarbon material is carried out on several dividing stages in cyclone evaporators with a heated cylindrical vertical wall. The inventive method consists in supplying the raw material heated to the initial boiling point of a first high-boiling fraction to the first stage evaporator, in removing a liquid phase therefrom in the form of a marketable product, in cooling a withdrawn vapour fraction to the lower boiling point of a subsequent phase, in directing said fraction for separation to a next evaporator and in obtaining therein a gasoline in the form of a vapour fraction and a distillation residue. The inventive plant for carrying out said method comprises in series connected by pipelines heat exchangers , a raw material heating stove and equipment for one or several distillation stages each of which comprises an evaporator, a cooler, heat exchangers and intermediate collecting containers for target products. Each evaporator is embodied in the form of a heat-insulated cyclone evaporator provided with a heated vertical cylindric wall. The cooler of each stage is embodied in the form of an air-and-water heater.

Description

METHOD FOR REMOVING HYDROCARBON RAW MATERIALS AND INSTALLATION FOR

ITS IMPLEMENTATION.

Technical field

The invention relates to the processing of oil in small-tonnage modular units (mini refineries (oil refineries) to produce motor and boiler fuel oils (gasoline, diesel fuel, fuel oil).

State of the art

Modern large-tonnage hydrocarbon distillation methods in their hardware design include pumps, heat exchangers, tube furnaces, distillation columns. Small-scale primary distillation plants repeat the fundamental technological solutions of similar large-scale distillation plants. At the same time, the hardware design of the distillation process is characterized by high metal consumption and requires significant capital investments.

Given the high cost and complexity of operation of small-tonnage plants made according to the scheme of large-tonnage oil refineries, unconventional technological solutions for the distillation of hydrocarbons with refusal, primarily from distillation columns, are constantly being developed.

A known method for the primary distillation of hydrocarbon feedstock (RF patent Zh2200182, publ. 2003.03.10), in which the separation of oil into fractions is carried out using a cyclone phase separator and a contact evaporator. In this case, either a gasoline fraction and a stripped heavy residue are obtained in a continuous mode, or a gasoline fraction, diesel fuel and boiler oil are selected during periodic operation of the installation. Raw materials are heated in recuperative heat exchangers and separated in a phase separator into liquid and vapor phases. The liquid phase in the dispersed state flows countercurrently into the vapor space of the contact evaporator. The vapor phase is additionally heated to 30-50 C above the temperature of the liquid phase and is supplied as a stripping agent through a bubbler distributor to the volume of the liquid phase located in the lower zone of the contact evaporator. The gasoline fraction is obtained by condensation of the vapor phase from the evaporator. To obtain diesel fuel, the topped residue is circulated through steam a heater and a phase separator, as a result of which superheated vapors of diesel fuel in a contact evaporator at 250-300 C are used for steaming boiler-furnace fuel (residues of raw material processing).

A disadvantage of the known method is that the use of centrifugal force in the phase separator serves only to intensively separate the vapor and liquid phases, but instead of the declared accuracy of separation into fuel fractions, triple enrichment of the light fraction will occur by triple vaporization of the liquid phase by superheated vapors of the selected light fraction heavy fraction vapors. In this case, the liquid (heavy fraction) will be enriched in light fractions. This follows from the classical laws of Dalton and Raul (P. Lebedev, Heat exchangers, drying and refrigeration units, M., Energia, 1966, p. 138-140) as applied to the used phase separator and evaporator designs, in which the concentration of vapor of heavy fractions there is always a higher concentration of light fractions (due to the significant constant volume of the liquid phase of the heavy fraction in these containers), which means that upon condensation of these vapors you get: instead of gasoline, a mixture of gasoline and diesel fuel; instead of diesel fuel - a mixture of gasoline, kerosene and oil fractions. And these mixtures will not be applicable as motor fuels.

In addition, such an application of a centrifugal phase separator has another significant drawback that reduces the clarity of the separation of hydrocarbon feeds into fractions - this is the cooling of the vapor-liquid mixture as a result of the expansion work. In this case, part of the light fractions of the molset condense and go into the liquid phase to heavy fractions. Calculations show that the width of this range of condensed fractions on the boiling point scale is about 2 ^° C. In addition, twice as much loss of light fractions due to condensation and escape into the liquid phase occurs due to heat loss to the environment, even for a well insulated centrifugal phase separator - cyclone. Depending on the composition of the raw materials, the resulting losses and impact on quality indicators can reach 5-10%, and this is very significant for the oil industry.

The closest in technical essence and the achieved result to the claim is the method described in certificate Ne 17004 of 03/10/2001 for a utility model Oil refining station for dispersal of multicomponent mixtures ”. The known method includes several stages of distillation, in in which the feed is heated to the lower boiling point of the first fraction, the resulting vapor-liquid mixture is fed to the distillation stage, in each of which the vapor-liquid mixture is divided into vapor and liquid phases, the liquid fraction is taken as the target product, and the vapor phase is cooled to the lower boiling point of the next fraction . The vapor phase of the last stage of distillation is condensed and discharged as the target product.

A disadvantage of the known method is the impossibility of obtaining a clear separation of the components into fractions, and therefore obtaining high-quality motor fuels. The reason is that there is a large volume of liquid with heavy fractions in the evaporator, and there are very few light fractions entering the vapor-liquid mixture. But according to the laws of Dalton and Raul (PD Lebedev, Heat exchangers, drying and refrigeration units, M., Energia, 1966, p. 138-140), the concentration of heavy fraction vapors above the surface of the liquid in the evaporator will be higher than that of light fractions, and hence in the cooler will go along with light fractions a significant amount of heavy fractions. In this case, part of the light fractions according to the same laws of Dalton and Raul will remain in the liquid phase in the evaporator.

There is a known installation for distillation of a ternary mixture (PD Lebedev, Heat-exchange drying and refrigeration units, M., Energia, 1966, p. 151, Fig. 5-11). The installation contains a condenser and two stages of acceleration, each of which includes a distillation cube, distillation column, reflux condenser, separator, mixture heaters and containers for collecting mixture components. In the first stage of the installation, a residue with a high content of a high boiling component is obtained, and part of the distillate with more volatile components enters the second stage. In the second stage, the remainder produces another component, and the most volatile of the three components enters the capacitor.

A disadvantage of the known installation is the large mass and dimensions, because distillation column is a vertical cylinder made of steel, cast iron or ceramics, the height of which reaches 30 m, diameter 5 m. Such an installation cannot be moved to the processing site, it can only work stationary. The known installation requires the use of water vapor at high pressures, which complicates its operation and maintenance. Closest to the claimed one is a refinery for distillation of multicomponent mixtures (RF certificate 342.17004 dated 03/10/2001 for a utility model), containing a line for supplying the oil mixture and lines for removing liquid fractions, connected in series by pipelines to several stages for dispersing the oil mixture, each of which includes a condenser and oil mixture heater, and heat exchangers, which are combined recuperative heaters, sequentially installed on the oil mixture supply line and oil mixture and coolers, as well as pump and oven for heating the oil mixture. Each stage of the oil mixture distillation is equipped with an evaporator with an integrated oil mixture heater made in the form of a furnace device for burning liquid or gaseous fuels.

The disadvantage of this installation is that it is impossible to obtain a clear separation of the components into fractions, and therefore, to obtain high-quality motor fuels (gasoline and diesel fuel). The reason is that there is a large volume of liquid with heavy fractions in the evaporator, and there are very few light fractions entering the vapor-liquid mixture. But according to the laws of Dalton and Raul, the concentration of vapors of heavy fractions above the surface of the liquid in the evaporator will be higher than the vapors of light fractions, which means that a significant amount of heavy fractions will go to the cooler along with light fractions. In this case, part of the light fractions according to the same laws of Dalton and Raul will remain in the liquid phase in the evaporator. A certain level of liquid in the evaporator is supported by the operation of a valve device through which excess liquid is discharged. Obviously, as a result of the operation of such an installation, gasoline, diesel fuel and very low quality fuel oil will be obtained.

Disclosure of invention

The main objective of the proposed group of inventions is to create a method for the distillation of hydrocarbons and plants for its implementation, allowing to obtain high quality petroleum products in a compact and small-sized installation.

The problem is solved in that in the method of distillation of hydrocarbon feedstock, comprising several stages of distillation, the feedstock is heated to the lower limit of the boiling point of the first fraction, the vapor the liquid mixture is fed to the distillation stage, in each of which the vapor-liquid mixture is divided into vapor and liquid phases, the liquid fraction is taken as the target product, and the vapor phase is cooled to the lower limit of the boiling temperature of the next fraction. New is that the separation into the vapor and liquid phases at all stages of distillation is carried out in cyclone evaporators with a cylindrical vertical wall, while the vertical wall of each evaporator is heated.

It is optimal that the level of output of the target product from the cyclone evaporator relative to the surface of the earth should not be lower than the maximum possible level of the target product in the intermediate storage tank, and the input of the target product into the intermediate storage tank should be below the minimum possible level of the target product.

It is advisable to adjust the heating power of the vertical cylindrical wall of each cyclone evaporator so that the temperature of the vapor-liquid mixture at the inlet of the cyclone evaporator is equal to the temperature of the vapor phase at its outlet.

It is optimal to cool the vapor phase with an adjustable air flow. The number of obtained fractions of the target product by boiling point is n + 1, where n is the number of cyclone evaporators.

The problem is also solved by the fact that the installation for distillation of hydrocarbon feedstock contains a feed line and a target product removal line, heat exchangers installed in series on a feed line, a pump and a furnace for heating the feed, and at least one pipe connected in series or several stages of distillation of raw materials, each of which includes an evaporator and a cooler connected in series by pipelines, the evaporator of each stage being connected by a pipeline with a corresponding it is a heat exchanger, the New one is that the installation additionally contains intermediate storage tanks for the target products installed on the removal lines of the target products after the heat exchangers, and the evaporator is made in the form of a cyclone evaporator that is heated from, for example, a vertical cylindrical wall, heated, for example, by electric heaters. It is advisable to install temperature sensors at the inlet and outlet of the cyclone evaporator of each distillation stage.

Optimally, the cooler of each stage of distillation is made in the form of an air-air heater. The claimed method for the distillation of hydrocarbon raw materials and the installation for its implementation are different from the closest analogues, therefore, the claimed solutions satisfy the condition of patentability of the invention of “new”.

An analysis of the prior art for compliance of the claimed solutions with the patentability condition of the invention “inventive step)) showed the following.

In the presented method for the distillation of hydrocarbon feedstock and a plant operating on its basis, in contrast to the known ones, a cyclone evaporator with a cylindrical vertical wall is used for separation into a vapor and liquid phase, which is heated to the lower boiling limit of the fraction intended for removal as the target product . The velocity (about 20 m / s) of the vapor-liquid mixture at the inlet to the cyclone and the velocity diagrams in the cyclone are such that only a small part of the heavy fraction vapors can escape from the pairs of light fractions due to turbulence at the boundary between the regions with pairs of light and heavy fractions . The combination of this effect with the additional possibility of compensating for heat losses caused by the expansion of vapors at the inlet of the cyclone evaporator and heat transfer to the environment by heating the vertical cylindrical wall makes it possible to obtain a clear separation of hydrocarbon materials into fractions and obtain high-quality target products. Due to the free flow of the liquid phase along the walls of the cyclone evaporator into the pipeline, into heat exchangers and intermediate storage tanks due to gravitational forces and excessive vapor pressure in cyclone evaporators, they do not form a stationary liquid level of heavy fractions, which means that heavy vapor does not accumulate fractions and breakthrough of a noticeable amount of vapors of heavy fractions into products with light fractions. It also contributes to obtaining quality targeted products.

The claimed inventions are so interconnected that they form a single inventive concept, since one of them is intended to implement another, therefore, this group of inventions satisfies the requirement of unity of invention.

Brief Description of the Drawings The invention is illustrated by drawings, where in FIG. 1 shows the technological scheme of the installation for the distillation of hydrocarbons; in FIG. 2 - sectional cyclone evaporator; in FIG. 3 - diagrams of vapor velocities of light and heavy fractions in a cyclone evaporator; in FIG. 4 is a connection diagram of a cyclone evaporator with an intermediate storage tank.

An example embodiment of the invention

Installation for the distillation of hydrocarbon raw materials (Fig. 1) contains connected in series pipelines 1st, 2nd and 3rd stages of distillation of raw materials, a line 4 for supplying raw materials, a pump 5 and a furnace 6 for heating raw materials, connected by a pipeline to the 1st stage distillation. Heat exchangers 7, 8 and 9 are installed in series on line 4 of the supply of raw materials. The 1st stage of raw material distillation contains a cyclone evaporator 10, a cooler 11, the 2nd stage of raw material distillation - a cyclone evaporator 12, a cooler 13, the 3rd stage of raw material distillation - a cyclone evaporator 14, a cooler 15. Each cyclone evaporators 10, 12, 14 of each distillation stages are communicated by pipelines respectively to coolers 11, 13, 15. Heat exchangers 7, 8, 9 are connected respectively to cyclone evaporators 10, 12, 14 of the 1st, 2nd, 3rd distillation stages. On the removal lines of the target products after heat exchangers 7, 8, 9, intermediate storage tanks 16, 17, 18 are installed for collecting fuel oil, diesel fuel and naphtha, respectively. The installation contains a container 19 for collecting the target gasoline product. At the inlet and outlet of the cyclone evaporator of each distillation stage, temperature sensors 20, 21, 22, 23, 24, 25 and 26 are installed.

The cyclone evaporator (Fig. 2) of each distillation stage consists of a cylindrical and conical parts and contains a casing 27, a heater 28, electric heaters 29, an inlet pipe 30, an outlet pipe 31, an outlet channel 32 for the vapor phase, an outlet 33 for the liquid phase. The installation uses the classical design of the cyclone evaporator, which is expressed in the proportions of the ratios of the geometric dimensions of the inlet pipe, the diameters and length of the cylindrical part of the cyclone, as well as the length of its conical part. δ

Heat exchangers 7, 8, 9 are combined recuperative heaters and coolers, chillers 11, 13, 15 are water-air heaters, in which the vapor is cooled by a controlled air flow from the fans, the pump is used gear, and the tube furnace. As temperature sensors, for example, thermocouples can be used.

Installation works as follows.

The hydrocarbon feed is pumped to the furnace 6 for heating, where it is heated to the lower boiling point of the first fraction (fuel oil), for example 360 ^° C. From the furnace 6, the heated raw materials enter the cyclone evaporator 10 of the 1st distillation stage, which maintains a temperature of 360 ° C, due to the heating of the vertical cylindrical wall by electric heaters 29, and in which the resulting vapor-liquid mixture is divided into vapor and liquid phases. Centrifugal force is used to separate the vapor-liquid mixture. So, for example, when a steam-liquid mixture stream preliminarily dispersed by heating is supplied to a curved surface at a speed of 10 m / s and a radius of curvature of 5 cm, an artificial gravity field is created, which is approximately 200 times greater than Earth's gravity. In this case, rapid coagulation of the liquid with a sharp decrease in the phase separation surface prevents the reverse absorption of hydrocarbon components from the vapor phase. On the heated vertical cylindrical wall of the cyclone evaporator in the form of a thin film flows the liquid phase of the processed raw materials.

The liquid phase (fuel oil) from the cyclone evaporator 10 enters the tubular heat exchanger 7, where it is cooled and then poured into the intermediate storage tank 16. The vapor phase is cooled in the cooler 11 to the lower boiling point of the second fraction, for example 200 ° C, and fed to cyclone evaporator 12 of the 2nd stage of distillation, in which the vapor-liquid mixture is divided into vapor and liquid phases. The liquid phase (diesel fuel) is fed into the tubular heat exchanger 8, where it is cooled and then poured into the intermediate storage tank 17. The vapor phase from the cyclone evaporator 12 of the 2nd distillation stage enters the cooler 13, where it is cooled to the lower boiling point of the third fractions, for example 17O ⁰ C, and fed to the cyclone evaporator 14 of the 3rd stage of distillation, in which the vapor-liquid mixture is separated into vapor and liquid phases. Liquid phase (naphtha) is fed into a tubular heat exchanger 9, where it is cooled and then poured into an intermediate storage tank 18. The vapor phase from the cyclone evaporator 14 enters the cooler 15, after which the resulting gasoline is poured into the tank 19. The power of the vertical cylindrical wall cylinders of the cyclone evaporators is regulated temperature sensors 20-26 at the inlet and outlet of the cyclone evaporators 10, 12, 14, and the readings of the temperature sensor at the outlet should match the readings of the temperature sensor at the entrance to the cyclone evaporator. The movement of the liquid phase from cyclone evaporators into storage tanks through heat exchangers is due to the action of gravitational forces and excessive vapor pressure of hydrocarbons.

Industrial applicability The proposed method for the distillation of hydrocarbon feedstocks and a plant based on it allow one to build an efficient small-sized plant with a clear separation of hydrocarbon feedstocks into fractions and produce high-quality products, including motor fuels without the use of distillation columns. This allows to significantly reduce the material consumption of the oil refinery, which means to reduce construction costs and reduce the time of commissioning of the oil refinery. As a result, the efficiency of invested funds is significantly increased, especially when developing new oil fields. No less effective may be the proposed method and device for the separation of other liquid mixtures (for example, the production of alcohol, etc.).

Claims

Claim

1. A method of distillation of hydrocarbon feedstock, comprising several distillation stages, in which the feedstock is heated to the lower limit of the boiling point of the first fraction, the resulting vapor-liquid mixture is fed to the distillation stages, in each of which the vapor-liquid mixture is separated into vapor and liquid phases, the liquid fraction is withdrawn as the target product, and the vapor phase is cooled to the lower limit of the boiling point of the next fraction, characterized in that the separation into the vapor and liquid phase at all stages of distillation is carried out in cyclone evaporators with the cylindrical vertical wall, the rear vertical wall is carried out each cyclone evaporator.

2. The method according to p. 1, characterized in that the level of output of the target product from the cyclone evaporator relative to the earth's surface should not be lower than the maximum possible level of the target product in the intermediate storage tank, and the input of the target product into the intermediate storage tank should be below the minimum possible level of the target product.

3. The method according to p. 1, characterized in that the heating power of the vertical cylindrical wall of each cyclone evaporator is controlled so that the temperature of the vapor-liquid mixture at the inlet of the cyclone evaporator is equal to the temperature of the vapor phase at its outlet.

4. The method according to p. 1, characterized in that the cooling of the vapor phase is carried out by an adjustable air flow.

5. The method according to claim 1, characterized in that the number of obtained fractions of the target product according to boiling points is n + 1, where n is the number of cyclone evaporators.

6. Installation for the distillation of hydrocarbons, containing a feed line and a target product removal line, heat exchangers, a pump and a furnace for heating the feed, and at least one or more feed distillation stages connected in series to the feed line, each of which includes an evaporator and a cooler connected in series by pipelines, and the evaporator of each stage is connected by a pipeline with a corresponding heat exchanger, characterized in that it additionally contains intermediate storage tanks for the target products, installed on the exhaust lines of the target products after the heat exchangers, and the evaporator is made in the form of a cyclone evaporator, heated, for example, by electric heaters, with a vertical cylindrical wall.

7. Installation according to claim 6, characterized in that temperature sensors are installed at the inlet and outlet of the cyclone evaporator of each distillation stage.

8. Installation according to claim 6, characterized in that the cooler of each stage of distillation is made in the form of a water-air heater.