TECHNICAL FIELD

The present invention relates to a device for capturing gasoline vapors at gas stations, which will find application in the purification of waste gases from volatile organic compounds, and in particular in the recovery of vapors during filling of the underground tank with gasoline at gas stations, and as well any excessive vapors from incomplete balancing between the car and the underground tank.

BACKGROUND OF THE INVENTION

Volatile organic compounds emit a photochemical oxidant by reaction with nitrogen oxides in the presence of sunlight. Their sources are many and varied: thermal processes, use of organic solvents, transport and treatment of liquid fuels and light organic compounds, refineries and others. Some volatile organic compounds are known to be highly toxic, mutagenic and carcinogenic.

Volatile petroleum products, such as gasoline, release vapor during storage, transportation, loading or unloading. Prior to the introduction of gasoline vapor capture systems, this vapor was released into the atmosphere. Petrol fumes Gasoline vapor released when refueling motor vehicles are harmful to human health and the environment. All gas stations must be equipped with a system to capture gasoline vapors in order to achieve cleaner air. In such well-known systems, the gasoline vapors transferred to the gas station tank or returned to the gas station for a new sale. The refueling stations are designed so that while filling the cars, they take the gasoline vapor back. Subsequently, when the tank of the gas station is filled, at the same time the vapor in it passes back to the tank truck through the so-called gas phase pipe. The vapors from the tank trucks is taken to the oil base, where it is used, thanks to the systems for liquefaction of gasoline vapors.

The known systems cannot achieve a better efficiency of 65 to 70% of the vapor recovery and therefore the environment is polluted during the filling of the underground tanks with petrol.

SUMMARY OF THE INVENTION

The object of the invention is to provide a device for capturing gasoline vapors at gas stations, which is automated and provides both efficient capture of gasoline vapors during filling of the underground tank with gasoline and reduced environmental pollution.

The problem was solved by creating a device for capturing gasoline vapors at gas stations, which includes a first activated carbon filter and a second activated carbon filter, connected by a first inlet valve and a second inlet valve, respectively, and a detonation fuse with a vent steam on underground tanks at a gas station. The first activated carbon filter and the second activated carbon filter are connected respectively by a first vacuum valve and by a second vacuum valve with a vacuum pump. The vacuum pump is connected to a first absorber, which is connected to a second absorber. The second absorber is connected to the first inlet valve and to the second inlet valve of the activated carbon filters. The two absorbers are connected via a petrol pump and a three- way petrol supply valve to a buffer tank equipped with a level transmitter. The buffer tank is connected via a petrol return valve as well as the three-way petrol supply valve to an underground tank at the gas station. The first activated carbon filter and the second activated carbon filter are connected, respectively, by a first outlet valve and a second outlet valve to a fresh air outlet line.

The advantage of the created device is that it provides efficient capture of gasoline vapors during filling of the underground tank with gasoline at optimized time for regeneration of the process and with the ability to accurately measurement the quantity of recovered product.

BRIEF DESCRIPTON OF THE FIGURES

The present invention is illustrated in the attached figure 1, which is a schematic diagram of a device for capturing gasoline vapors at gas stations according to the invention.

DETAILED DESCRIPRION OF EMBODIMENT OF THE INVENTION

The created device for capturing gasoline vapors at gas stations, shown in Figure 1, is installed on a flat concrete base near the underground storage tanks. Its steam inlet is connected to the existing steam vent of the underground tanks. The steam vent must be equipped with a vacuum pressure relief valve.

The created device includes a first activated carbon filter 1 and a second activated carbon filter 2, connected by a first inlet valve 1.1 and a second inlet valve 2.1, respectively, and through a detonation fuse 9 with a vent for steam 10 of underground tanks at a petrol station. The detonation fuse 9 at the entrance isolates the created equipment from the storage tanks.

The first activated carbon filter 1 and the second activated carbon filter 2 are connected respectively by a first vacuum valve 1.3 and by a second vacuum valve 2.3 by a vacuum pump 3. The vacuum pump 3 is connected to a first absorber 4 which is connected to a second absorber 5. The second absorber 5 is connected to the first inlet valve 1.1 and to the second inlet valve 2.1 of the activated carbon filters 1 and 2. The two absorbers 4 and 5 through a petrol pump 7 and a three-way petrol supply valve 7.1 are connected to a buffer tank 6 with level transmitter 8. The function of the buffer tank 6 is to dose the regenerated product. The buffer tank 6 is equipped with an overflow plate and a measuring cell with a level transmitter 8 for level measurement. The difference in level between the beginning and the end of the regeneration cycle shows the quantity of recovered product during one cycle. The buffer tank 6 is connected to the underground tank of the petrol station via a petrol return valve

6.1 and the three-way petrol supply valve 7.1.

The first activated carbon filter 1 and the second activated carbon filter 2 are connected, respectively, by a first outlet valve 1.2 and by a second outlet valve 2.2 to a fresh air outlet pipe.

The created device for capturing gasoline vapors at gas stations is used as follows:

In standby mode, the first inlet valve 1.1 and the first outlet valve 1.2 are opened as the petrol vapor passes through the first activated carbon filter 1. After the process of unloading a petrol truck, the equipment is started manually. The activated carbon bed of the second activated carbon filter 2 is also switched on. The second inlet valve 2.1 and the second outlet valve 2.2 are opened. The vacuum pump 3 is started and the first inlet valve 1.1 and the first outlet valve

1.2 are closed. The petrol pump 7 is started and the first vacuum valve 1.3 is opened to start the regeneration of the first activated carbon filter 1.

The highly concentrated vapors are absorber from the first activated carbon filter 1 with the vacuum pump 3 to be reabsorbed in the columns of the two absorbers 4 and 5 by counter flow of gasoline pumped from the buffer tank 6 through the gas pump 7 and the three-way gasoline valve 7.1. The lean absorbent is returned directly to the buffer tank 6 via the petrol return valve 6.1. After regeneration, the activated carbon layers of the first activated carbon filter 1 are replaced and regeneration continues through the second activated carbon filter 2, closing the second inlet valve 2.1 and the second outlet valve 2.2 and opening the second vacuum valve 2.3.

The return of the absorbent from the buffer tank 6 is carried out in a return line to the underground storage through the return valve for petrol 6.1. During the regeneration cycle, the volume of the absorbent increases. Excess absorbent passes through the overflow plate and accumulates in the measuring cell. The difference in level between the beginning and the end of the regeneration cycle is measured by the transmitter level 8 and shows the amount of recovered product. After each regeneration cycle, the absorbent must be refreshed.

The device is protected from overflow by a pipe connected directly to the underground storage. The device is fully automated and switches itself off in case of malfunction.