RU41004U1 - INSTALLATION OF CAPTURE AND RECOVERY OF MOTOR FUEL VAPORS FROM RESERVOIRS OF OIL PRODUCTS AT FUEL MARKET OBJECTS - Google Patents

Abstract

The utility model relates to the design of installations intended for the storage of petroleum products used in the petroleum, petrochemical and oil refining industries, in particular during the storage and retail sale of gasoline in urban nuclear power plants. An installation for capturing and recovering hydrocarbon vapors from oil product tanks is proposed. It contains a tank in the form of a tank (1) interconnected by a system of heat-insulated pipelines (1) for storing a petroleum product, including a cavity with liquid petroleum product, an evaporator-heat exchanger (3) and a condensate drain line into the tank (5). As well as a condensate tank for separating gasoline and water (8), which includes a baffle, which is a hydrostatic shutter, a solenoid valve (10), a level sensor (9), an opening valve through which it is condensed in evaporator-heat exchangers (7), (3) the oil product also flows back to the tank (1).

Description

The utility model relates to the design of facilities for storing petroleum products used in the petroleum, petrochemical and refining industries, as well as other industries related to the storage of volatile petroleum products, for example, during storage and retail sale of gasoline in urban nuclear power plants.

The proposed device can be used where storage and distribution systems for petroleum products are used: gas stations, oil depots, oil refineries, motor transport enterprises, in the territory of which refueling is carried out, etc.

The objective is to reduce losses of petroleum products due to the capture of hydrocarbons from the vapor-air mixture emitted into the atmosphere from underground or ground tanks containing hydrocarbon liquids (oil, gasoline, kerosene, etc.) by condensation of hydrocarbon vapors, which leads to an improvement in environmental and fire conditions in the area where the tanks are located (above ground, underground) with any cross-sectional shape with the oil products stored in them. The latter is especially important for megacities, such as Moscow, with a high concentration of road transport and dense urban development.

A technical solution is known to reduce the loss of volatile products, according to which a vapor-air mixture (PVA) is passed through a two-stage cooling system. First

the stage cools the PVA to a temperature of plus 0.5-1.5 ° C, the second to minus 1-7 ° C (US patent No. 3266262, CL 62-54). The disadvantage of this invention is that the indicated cooling temperature is insufficient for efficient (more than 50%) capture of hydrocarbons (see the book Konstantinov NN, Combating losses from evaporation of oil and oil products, M., "Gostoptekhizdat", 1961, p. 185). In addition, the temperature of the outgoing PVA is different from the ambient temperature, which leads to freezing of the breathing valves (in the warm season) and low thermodynamic efficiency of the installation (the cost of cold for cooling the environment).

A technical solution is known for storing petroleum products with vapor recovery (AS USSR No. 1406074, class B 65 D 90/30, 1988), according to which PVA is condensed by sparging the latter through a condenser filled with refrigerated oil. Pre-cooling the PVA to 0 ° C with a return flow of cold air allows both to avoid ice plugs (when water freezes) and to reduce the energy consumption for pre-cooling (up to 0 ° C) of the PVA. The disadvantage of this method of cooling PVA is its limited capabilities, since the cold return flow of the expired air is not enough.

A technical solution is known, also aimed at storing petroleum products with vapor recovery (AS USSR No. 1406075, B65D90 / 30, 1988), consisting in the selection of PVA from the gas space (GP) of the reservoir, passing it in a bubble through mode through the same oil product and the return of air after bubbling back to the reservoir GP. The bubbling oil product is cooled to a temperature below the temperature of the corresponding bottom layers of the oil product and above a temperature corresponding to zero partial vapor pressure by cooling with a low-temperature refrigerant and thermostating by penetration into the soil.

However, this solution has its limited use for tanks with a variable cross-section (cylindrical type RGS, trapezoidal), since it is impossible to use effective floating protective coatings in these types of tanks. The latter circumstance is important, since when PVA is depleted in the GP, due to condensation of hydrocarbons and the return of clean air to the GP of the reservoir, the latter is saturated with hydrocarbons (additional evaporation from the surface of the liquid), which leads to an increase in the intra-reservoir pressure (reverse expiration). Despite the fact that the returned, purified air has a lower temperature than the selected mixture, this effect takes some time, since the cooling rate of the GP by the returned air, and therefore the upper layers of oil products, is lower than the rate of evaporation of the latter in space by unsaturated hydrocarbons. In this solution, a floating coating is used and therefore an arbitrarily small depletion or cooling of the GP of the reservoir is possible without compromising the safety of the oil product. Moreover, the rate of increase in the concentration of hydrocarbons is several times lower than over an unprotected surface.

Other technical solutions are also known in the art, US Pat. No. 5,469,986, 1995; US patent No. 5490873, 1996; U.S. Patent No. 5,185,486, 1993; Japan Patent No. 08-048984, 1996; RF patent No. 2050170, 1995; RF patent No. 2193001, 2002

However, all known designs of hydrocarbon vapor recovery and utilization systems from oil product tanks have a number of disadvantages associated either with high material costs and the difficulty of their operation, or with insufficient efficiency and limited use.

The objective of the proposed utility model is to reduce the concentration of emitted hydrocarbons into the atmosphere to the value of the upper concentration limit of vapor explosion (for

gasoline 5.2%), reduction of losses of oil products during storage and delivery, utilization of hydrocarbon vapors for tanks with any cross-sectional shape in the absence of a floating pontoon coating, implementation on the basis of available components.

To solve this problem, a design was developed for a unit for capturing and utilizing hydrocarbon vapors from oil product tanks, containing a tank in the form of a tank (1) interconnected by a system of heat-insulated pipelines, for storing an oil product, including a cavity with a liquid oil product and a gas cavity with a vapor-air mixture insulated from the surrounding medium pipeline (2), through which the air-vapor mixture enters the evaporator-heat exchanger (3), cooled by a refrigeration machine (4), after torogo peeled pair enter the atmosphere and an overflow line (5) in the condensate oil reservoir (1) ,.

To increase the degree of condensation of hydrocarbons and reduce the amount of freezing moisture in the heat exchanger, the evaporator-condenser (3) can be made of 2 baths, the first of which (3 ') serves to cool the PVA to a temperature of +0.5 ... + 1 ° С and the second (3 ") for cooling to the desired low temperature, in particular from -80 to -40 ° C, while the first stage has a means of water drainage (6).

At the same time, in order to maximize the thermodynamic efficiency of the installation, in order to maximize the cold use of the purified PVA stream, the dual-flow condenser-heat exchanger (3 ') is replaced by a three-flow (3 "), and a recuperative heat exchanger cooled by the reverse (dried and purified from hydrocarbons) PVA is added (7) with condensate drain line.

In order to further improve the process of cleaning PVA and separating the condensed water-hydrocarbon mixture into components obtained in heat exchangers-condensers (7), (3 '"), (3"), the condensate enters the condensate sump (9), consisting of a housing from

an inclined baffle, which is a separator with a hydrostatic shutter, separates the mixture by changing the height of the liquid column, including a condensate level sensor (9), a solenoid valve (Yu), which opens when the level sensor (9) is activated.

To achieve the simplicity of the system, increase the degree of extraction of light fractions, thermodynamic efficiency, reduce costs, increase the service life, ease of modernization, the previously discussed chiller (4) is divided into 2: a chiller, cooling to a temperature of -20 ° C (4 ') and chiller designed to achieve lower temperatures (from -20 ° C to -40 ...- 80 ° C). This decision is due to both the various hardware design of the above chillers and their more economical operation, since a 80% cold return flow is enough for three-flow heat exchangers (3 '") to work and thus the chiller (4') works only with initial cooling - the unit enters the mode. Its further switching on is much less frequent than that of the chiller (4 "), which increases the life of the chiller (4 ') and decreases both the electric power consumed by it, and total installation.

The essence of the proposed utility model is illustrated in figures 1-5:

Figure 1 - image of the main block diagram of the installation;

Figure 2 - image of a block diagram of an installation with a separate two-stage main evaporator-heat exchanger 3 ', 3 ";

Fig.3Z - image of a block diagram of the installation with additional recuperative heat exchanger and three-flow evaporator 3 '"

Figure 4 - image of a block diagram of the installation with the main evaporator 3 ", an additional recuperative heat exchanger, a three-flow evaporator 3" '' and a tank condensate collector-separator 8, equipped with a level sensor 9 and a solenoid valve 10 on the drain line

condensate.

Figure 5 - image of a block diagram of the installation with the main evaporator 3 "connected to an additional refrigeration machine 4", used for cooling to temperatures (-40 ...- 80) ° C, additional regenerative heat exchanger 7, three-flow heat exchanger-evaporators 3 '' ', a condensate tank 8 / equipped with a level sensor 9 and a solenoid valve on the condensate drain line 10, and.

Designations in figures 1-5:

1 - underground reservoir (capacity);

2 - insulated vapor supply pipe;

3 - evaporator-heat exchanger;

3 - double-flow evaporator of the first stage;

3 "- two-line evaporator of the second stage;

3 '' '- three-flow evaporator;

4 - refrigeration machine (XM);

4 '- the main refrigeration machine of the first stage;

4 "- additional refrigeration machine of the second stage;

5 - condensate drain line;

6 - water drainage means;

7 - additional recuperative heat exchanger;

8 - tank-collector / condensate separator;

9 - level sensor;

10-solenoid valve on the condensate drain line. Figure 1 shows a diagram of the proposed installation. Installation works as follows. In the storage, delivery of petroleum products, "big breath" (vapor displacement when filling the tank), the PVA is fed through a thermally insulated pipe 2 to the evaporator-condenser 3. cooled to a low temperature (-20 ...- 80) ° С by a refrigeration machine 4. Formed while condensate through the pipeline (line) drain 5 enters the reservoir. Purified steam-air mixture (air) enters

the atmosphere. Therefore, a decrease in the concentration of vapor in the atmosphere at the location of the reservoir 1 leads to an increase in fire safety of the gas station.

Figure 2-5 shows a diagram of the proposed modifications of the installation. Since the composition of the steam-air mixture contains water, both dissolved in gasoline, so contained in air, cooling the mixture in heat exchangers leads to freezing of the latter, the appearance of frost, ice plugs on the PVA passage. This reduces the heat transfer and cooling efficiency of the vapor-air mixture, and as a consequence, the condensation of hydrocarbons. In order to prevent frost and frost, the heat exchanger-evaporator 3 is divided into two: 3'- the first stage evaporator-condenser, cooled to a temperature of +0.5 ... + 1.5 ° С, leading to the maximum release of water on it, drained along discharge line 6 and A 3 "evaporator-condenser of the second stage, which condenses higher boiling fractions of hydrocarbons than in a heat exchanger-evaporator 3 '. Because the heat of XM 4, especially with" big breaths "is spent on cooling the PVA from ambient temperature to the condensation temperature of the oil If it is appropriate to use the cold of the return (purified) stream to pre-cool the PVA (to temperatures of + 10 ° С + 5 ° С). For this purpose, the heat exchanger-evaporator-condenser 3 'is divided into two: 3 "- a three-flow evaporator and 7 - additional recuperative heat exchanger. In the recuperative heat exchanger-evaporator, the displaced PVA is pre-cooled to temperatures of +10 ... + 5 ° С, as well as the return flow (purified PVA) is heated to a temperature close to the ambient temperature, which leads to an increase in the thermodynamic efficiency of the installation, and a decrease in the consumed electricity and the absence of hoarfrost, frost on the outlet end of the outlet line of the purified vapors. Condensate formed during pre-cooling in a recuperative heat exchanger is also discharged into the tank

drain lines 5.

Since the cooling temperature of the PVA in the recuperative heat exchanger is in most cases lower than the dew point, the condensate formed contains water. To separate hydrocarbon condensate from water and reduce the moisture content in gasoline and the gas space of the tank, the unit is equipped with a device for collecting and separating water and gasoline into parts, consisting of a tank - a condensate collector / separator 8, a level sensor 9 and a solenoid valve (valve) 10. Tank the condensate collector consists of a partition, which is a static hydraulic lock, performing spatial separation of the water-gasoline mixture by changing the height of the liquid column (the difference in density of the latter), and the discharge ubkov. Water having a higher density than hydrocarbons is discharged from the lower pipe through a drain device. Upon reaching a certain level of gasoline, a level sensor 9 is triggered, which leads to the opening of the solenoid valve 10 and the condensate drain into the tank.

Obtaining higher degrees of PVA purification (up to 90 ... 95%) requires lower (less than -30 ° С) temperatures. In this regard, it is not effective to use one HM, since the cold of the return flow is quite enough for cooling, heat exchangers 3 '' and 7. Therefore, the chiller 4 is divided into two: the 4'-main chiller of the first stage, cooling the PVA to temperatures (-25 ...- 20) ° С, and a 4 "-additional refrigeration machine of the second stage; serves for cooling-condensation of hydrocarbons in the composition of PVA to lower temperatures (-80 ...- 20) ° С. To obtain more negative temperatures in refrigeration equipment uses a different type of XM than in the case of 4.4 ', which is due to the structural, technological features of the low-temperature technique. The equipment of the additional XM 4 "installation and a 3-inch two-flow heat exchanger-evaporator leads to an increase in the operating life of the XM 4', lower operating costs, due to

the use of cold backflow in a recuperative heat exchanger 7 and in three-flow evaporators of the second and first stages 3 ', 3' '', respectively.

The connection of the tank 1 with the recuperative heat exchanger 7 and the heat exchangers with each other is carried out in order to avoid the dispersion of cold into the environment and premature condensation / evaporation of the PVA, thermally insulated pipe 2.

The following specific elements can be used to create the proposed installation:

Tanks (tanks) for storing petroleum products manufactured by OJSC “Uraltechnostroy-Tuimazykhimmash”, Republic of Bashkortostan at 10, 25, 50, 75, 100 m ³ or commercially available GUP oil depot “Krasny Yar”, Novosibirsk Region, tanks of the type RGS / RGSP, EP etc. The refrigerating machine manufactured by ZAO Ostrov, Mytishchi or the company Nord, Moscow. Evaporator-heat exchanger up to + 1 ° С produced by OJSC “Uraltechnostroy-Tuimazykhimmash”, the Republic of Bashkortostan or ZAO Gazholodtekhnika, Moscow. Evaporator-heat exchanger up to -80 ...- 40 ° С produced by OJSC Uraltechnostroy-Tuimazykhimmash, the Republic of Bashkortostan or ZAO Gazholodtekhnika, Moscow. Tank condensate separator manufactured by GP Experimental Plant MSTU. N.E.Bauman, Moscow. Solenoid gas valve KA-1 FSUE “Plant named after M.I. Kalinina, St. Petersburg. Condensate level sensor RSF84Y100R CRYDOM.

Using the proposed installation allows not only to effectively reduce the concentration of hydrocarbons emitted into the atmosphere and the loss of oil products during their storage and delivery, but also to utilize hydrocarbon vapors in tanks with any cross-sectional shape, as well as ease of readjustment of existing nuclear power plants, oil depots, oil refineries, there is simplicity in maintenance and repair.

Claims (5)

1. Installation for collecting and recovering vapors of motor fuel from oil product tanks, containing a tank connected to each other by a piping system in the form of a tank (1) for storing a petroleum product, including a cavity with liquid oil and a gas cavity with a vapor-air mixture, a heat-insulated pipeline (2) to provide the selection of the steam-air mixture from the tank (1), the movement of the steam-air mixture through the evaporator-heat exchanger (3), a refrigeration machine (4) for cooling the steam-air mixture in the evaporator-heat exchanger (3), into which the air-vapor mixture enters from the tank (1), as well as a drain line (5), through which the oil product condensed in the evaporator-heat exchanger (3) is fed back to the tank (1). 2. Installation according to claim 1, characterized in that to increase the degree of condensation of hydrocarbons and reduce the amount of freezing moisture in the heat exchangers, the evaporator-heat exchanger (3) is made of two stages, the first of which (3 ') serves to cool the vapor-air mixture to a temperature of +1 to + 0.5 ° C, and the second (3 '') - to the required low temperature, in particular from -80 to -40 ° C, while the first stage (3 ') provides a means of water drainage (6) . 3. Installation according to claim 2, characterized in that in order to reduce the electric power consumed by the chiller (4), to prevent the release of cold air into the atmosphere, to increase the thermodynamic efficiency of the system, an additional heat exchanger (7), cooled by the return flow, is used, a double-flow heat exchanger (3 ') ) is replaced by a three-threaded (3````), reducing the operating time of the chiller (4). 4. Installation according to claim 3, characterized in that to increase the degree of efficiency of separating the water / gasoline mixture into parts, an additional condensate tank / sump (8) is used, equipped with a hydrostatic shutter, a level sensor (9) and a solenoid gas valve (10) that opens triggered level sensor (9). 5. Installation according to claim 4, characterized in that in order to lower the temperature of cooling the steam-air mixture, increase the degree of condensation of hydrocarbons, the refrigeration machine (4) is made of two, the first of which (4 ') serves to cool the steam-air mixture to a temperature of 25 .. . -20 ° С, and the second (4``) - to the required low temperature, in particular from -80 to -20 ° С.