RU2536504C1 - Organic compound vapour recovery unit - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: organic compound vapour recovery unit containing an emergency release tank with intake pipeline connected to a tank for collection of condensed and cooled organic compounds coupled by the respective pipeline, a pump for the tank emptying and nitrogen blanket filters is equipped additionally with an outlet pipe in the lower part of the emergency release tank and its outlet is closed by an explosive valve connected by the intake pipeline to the emergency release collector having safety valves; above the outlet pipe at brackets there several rows of perforated horizontal partitions, above the upper perforated partition and below the outlet pipe union installed in the emergency release tank a permanent level of water is maintained, and in the upper part of the emergency release tank there is an entrainment separator.

EFFECT: invention allows manufacturing of the unit with low power consumption, low service durability, easy maintenance and reliability.

8 cl, 5 dwg

Description

The invention relates to apparatuses of the oil refining and chemical industries, namely, recovery units - units for collecting and returning vapors of organic compounds for reuse in the same process, and can be used to localize and eliminate emergencies at chemical and technological objects.

Known installation of vapor recovery oil products company Aker Cool Sorption. Vapors collected from an emission source are sent to one of two working filters that are filled with activated carbon. The hydrocarbon components contained in the vapors are adsorbed on the developed surface area of activated carbon, and the purified air is sent to the atmosphere. Before the saturation state of the working filter, the vapor stream switches to the second, clean filter, after which the first filter is vacuum regenerated with the hydrocarbon stream directed to the absorption column, in which the counterflow of fresh absorbing liquid absorbs the hydrocarbon components from the vapor stream. The absorbent liquid and the newly absorbed hydrocarbon components are continuously recycled to the oil storage tank. Vapor recovery plants are used to capture and recover vapors of all types of petroleum products. Patent WO 2007076867 IPC B01D 53/047; B01D 53/053, publ. 2007-07-12.

Known installation of vapor recovery of oil products companies Carra Gi using the processes of adsorption and liquid absorption. Vapors collected from an emission source are sent to one of two working filters that are filled with activated carbon. The hydrocarbon components contained in the vapors are adsorbed on the developed surface area of activated carbon, and the purified air is sent to the atmosphere. Before the saturation state of the working filter, the vapor stream switches to the second, clean filter, after which the first filter is vacuum regenerated with the hydrocarbon stream directed to the absorption column, in which the counterflow of fresh absorbing liquid absorbs the hydrocarbon components from the vapor stream. The absorbent liquid and the newly absorbed hydrocarbon components are continuously recycled to the oil storage tank.

Kappa Gi vapor recovery units using adsorption and condensation processes are known. After adsorption in a working filter on the surface area of activated carbon, the flow of hydrocarbons during vacuum regeneration is directed to a coil-type condenser with a refrigerant circulating in the tube space. The pump returns condensate to the provided reservoir, and hydrocarbon vapors from the condenser are sent to the working filter.

Known installation of vapor recovery company Carra Gi using condensation and adsorption processes. Hydrocarbon vapors are immediately sent to the coil type condenser. The pump returns condensate to the provided reservoir, and the hydrocarbon vapor from the condenser enters one of two active carbon filters. After adsorption on the surface area of activated carbon, a vacuum regeneration process is carried out, during which the hydrocarbon stream is returned to the condenser inlet (www.kappagi.net).

A known installation for the recovery of hydrocarbon gases of volatile organic compounds (VOCs) generated during the loading of hydrocarbons in a tank containing one or more compressors for VOCs, a cooling system for compressed VOCs and a condensate tank for VOCs, in which of the invention, the compressor or compressors are connected to a respective steam turbine, and the VOC gas condensate reservoir is connected to the boiler to produce steam; while the condensate of the VOC gas is used as fuel in the boiler, and the boiler is connected to a steam turbine or to turbines. The boiler is connected to one of the turbines to drive the cooling compressor for the VOC gas. Preferably, the installation includes a heat exchanger for exchanging heat between the VOC gas condensate coming from the VOC gas condensate tank and the steam coming from the boiler, for regenerating the VOC gas condensate into the corresponding coating gas. Patent RU No. 2296092, IPC B65D 90/30, C10G 5/06, F17C 6/00 published: 03/27/2007.

A known installation for vapor recovery of petroleum products, containing a tank with a receiving pipe, a refrigeration unit, absorbers of the first and second absorption stages with irrigation pipes connecting the upper parts of the absorbers with a refrigeration unit, a receiving gas pipe connecting the vapor zone of the tank with the lower part of the first stage absorber, a pump installed on the line between the lower zone of the tank and the refrigeration unit, and the adsorber, additionally equipped with an absorbent stabilizer installed after the pump, the outlet pipe and the light fractions of which are connected to the lower part of the first stage absorber, and the liquid outlet pipe with a refrigeration unit, and a pipe jumper connecting the first stage absorber irrigation pipe to the receiving gas pipe, and the ratio of the diameters of the pipe jumper and the first stage absorber irrigation pipe is taken to be 1: 3 . Patent RU No. 2106903 B01D 53/14, B01D 53/75, published: 03.20.1998.

All of these installations are designed to capture volatile organic compounds and return to the process during stationary operation - during storage and transportation: loading in railway and tanker trucks, loading in tankers, storing products in storage tanks.

They include a fairly large number of devices and other equipment - activated carbon filters, absorption columns, condensers, heat exchangers, vacuum pumps, compressors, refrigerant tanks, etc.

During the production of organic compounds at chemical-technological facilities, a situation may arise when a liquid organic medium enters the vapor-liquid phase, as a result of which emergency situations can occur, the causes of which are different, for example: depressurization of any equipment, resulting in a sharp decrease in pressure in the system , the occurrence of an external fire, the cessation of circulating water supply, the failure of control valves.

In large installations of the chemical industry, during the emergency release of equipment of technological units, discharges of hundreds of tons per hour of vapor-liquid mixtures are possible. There are no analogues of systems for emergency dumping in such quantities with the preservation of expensive products at existing chemical plants. The vapor-gas phase is discharged to the flare unit, which leads to enormous losses, and the required load on the flare and the cost of the flare units are very high.

The task to which the claimed invention is directed is to ensure safety in case of emergencies of a technogenic nature, to create a reliable installation design for localizing and eliminating emergencies at chemical-technological facilities, which would ensure the preservation and return to production of large quantities of valuable chemical products and was quite simple in hardware design.

The solution to this problem is provided due to the fact that the vapor recovery unit for organic compounds, containing an emergency discharge tank with a receiving pipe, a condensed and cooled organic compounds collection tank, a pump for emptying it, nitrogen breathing filters, is additionally equipped at the bottom emergency dumping tank by an inlet pipe, the outlet of which is closed by an explosive valve connected by a receiving pipe to the collector a with a relief valve with safety valves, several rows of perforated horizontal partitions are located on the brackets above the inlet pipe, above the upper perforated partition and below the outlet fitting located in the emergency discharge tank, a constant water level is maintained, and a separator-droplet separator is provided in the upper part of the emergency discharge tank.

In addition, the outlet of the inlet pipe is located along the axis of the emergency discharge tank.

In addition, the number of rows of perforated horizontal partitions is determined by thermal engineering calculation.

In addition, the partitions are made of metal nets.

In addition, the partitions are made of two layers of flat slotted gratings made of a high-precision profile of a V-shape with longitudinal slots of a certain size.

In addition, the V-shaped profiles of each layer are perpendicular to each other with the formation of holes of square section.

In addition, the droplet separator is made of corrugated mesh.

The invention is illustrated by drawings.

Figure 1 - General view of the installation.

Figure 2 - section aa, the location of the inlet pipe with an explosive valve.

Figure 3 is a horizontal perforated partition made of two layers of flat slotted gratings.

Figure 4 - section bB.

Figure 5 - section bb.

The vapor recovery unit for organic compounds includes a cylindrical recessed emergency vapor recovery tank for organic compounds 1 with a flat bottom 2 and a conical cover 3, with an inlet pipe 4 located in its lower part below the cooling water level, the outlet of which, located along the tank axis, is closed explosive valve 5.

Inside the emergency discharge tank above the inlet pipe 4, in order to increase the degree of condensation of the vapors of organic compounds, several rows of perforated horizontal partitions 7 are located on the brackets 6, the number of which is determined by the heat engineering calculation. Partitions 7 can be made of metal grids or two layers of flat slotted gratings 8 made of a high-precision V-shaped profile with longitudinal slots of a certain size and having sufficient strength and rigidity, while the V-shaped profiles of each layer are perpendicular to each other the formation of holes of square section.

The inlet pipe 4 through the intake pipe 9 is connected to the emergency discharge manifold 10, which includes safety valves 11 of the installation equipment. An outlet fitting 12 is located in the emergency dumping tank 1, connected by a pipe 13 to a recessed cylindrical tank 14 for collecting condensed and cooled organic compounds having a flat bottom 15 and a conical cover 16. A pump 17 is used to empty the tank 14. The tank 1 and the tank 14 are installed nitrogen breathing filters 18, which allow you to capture products from the "small" and "large" breathing tanks on the valve and to prevent their release into the atmosphere.

To prevent the possible droplet dropping of organic compounds to the flare unit, a droplet separator 19 made of corrugated mesh is provided in the upper part of the emergency discharge tank 1, while the corrugations 120 mm high are tightly pressed against each other, creating almost absolute protection against droplet entrainment.

In the emergency discharge tank 1, a constant water level is maintained, above the upper perforated partition 7 and somewhat lower than the outlet fitting 12.

The operation of the vapor recovery unit for organic compounds is as follows.

In the event of an emergency at chemical-technological facilities during the production of organic compounds, when the liquid organic medium goes into an nonequilibrium state with the formation of a vapor-liquid phase, the safety valves 11, which are part of the emergency dump collector 10, automatically operate and move at high speed (up to 40 m / s) and under considerable pressure through the pipeline 9, the vapor-liquid mixture enters the inlet pipe 4, located under the level of cooling water in the lowest part of the tank and emergency release 1. There is a sharp contraction of the air in conduit 9 and the inlet pipe 4 and by a certain pressure calculated automatically activated working fluid pressurizing explosive valve 5 and the compressed air from the vapor-liquid mixture expelled from the nozzle to the level of cooling water. Under the lower perforated partition 7 in the entire diametrical section of the emergency discharge tank 1, a stable steam cushion is formed from vapors of the organic medium and water, forced through a vertically upward driving force through the openings of the partition. The heat transfer from the surface of the perforated partition 7 to the non-flowing water layer sparged by the steam passing through it is very high, so the vapors of organic compounds and water are quickly cooled. The specific volume of vapors and the size of steam bubbles during cooling tend to decrease, and on the other hand, due to a decrease in the hydraulic pressure of the cooling water column during the rise of steam bubbles upwards, they increase, but the decisive process is rapid cooling, since the rate of rise of bubbles is relatively small (20-40 cm / s). The number of perforated partitions 7 is determined by heat engineering calculation. Convection currents occur in the cooling water layer, the warmer layers of water rise up, the colder ones fall down, which helps to equalize the temperature of the water in the volume of the emergency discharge tank 1. At a certain depth, the vapors of organic substances and water condense, followed by cooling of the condensate, with condensate droplets organic substances having a density lower than the density of water, float with the formation of a surface layer and subsequent overflow of the organic medium through the outlet 12 and the pipeline 13 into a cylindrical container 14 for collecting condensed and cooled organic compounds. The process of condensation and collection of the product will continue until the excess pressure of the vapor-gas mixture of discharged organic substances exceeds the value of the hydrostatic pressure of the water column in the emergency drain tank 1 (0.03-0.07 MPa). The cooled organic medium is pumped out by pump 17 and returned to production. To prevent possible droplet entrainment to the flare unit, a separator-droplet separator 19 is provided in the upper part of the emergency discharge tank 1, the design of which allows to prevent droplet entrainment to the flare unit.

Installations of this design can be used to localize and eliminate emergencies at chemical and technological facilities in a wide range in terms of the volume of accidentally discharged organic substances, physical properties, pressure and temperature of process media.

The advantage of the vapor recovery unit for organic compounds is the ease of maintenance, reliability, safety, low power consumption, low operating cost.

Claims (8)

1. A vapor recovery unit for organic compounds, comprising an emergency discharge tank with a receiving pipe, a condensed and cooled organic compounds collecting tank, a pump for emptying it, nitrogen breathing filters, characterized in that it is further provided with an emergency discharge tank located at the bottom of the emergency tank discharge by an inlet pipe, the outlet of which is closed by an explosive valve connected by a receiving pipe to the emergency discharge collector, which has a pre anitelnye valves, above the inlet pipe is arranged on brackets several rows of perforated horizontal baffles, above the upper and below the perforated baffle nozzle outlet located in the emergency release reservoir maintained a constant level of water in the tank top emergency release is provided a separator-demister. 2. The vapor recovery unit of organic compounds according to claim 1, characterized in that the outlet of the inlet pipe is located along the axis of the emergency discharge tank. 3. The vapor recovery unit for organic compounds according to claim 1, characterized in that the number of rows of perforated horizontal partitions is determined by the heat engineering calculation. 4. Installation for the recovery of vapors of organic compounds according to claim 1, characterized in that the partitions are made of metal nets. 5. The vapor recovery unit for organic compounds according to claim 1, characterized in that the partitions are made of two layers of flat slotted gratings made of a high-precision V-shaped profile with longitudinal slots of a certain size. 6. The vapor recovery unit for organic compounds according to claim 5, characterized in that the V-shaped profiles of each layer are perpendicular to each other with the formation of square holes. 7. The vapor recovery unit of organic compounds according to claim 1, characterized in that the droplet separator is made of corrugated mesh. 8. The vapor recovery unit for organic compounds according to claim 7, characterized in that the corrugations of the mesh are made 120 mm high and are tightly pressed against each other.

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