RU2795646C1 - Adsorption-venting valve with removable membrane - Google Patents

Abstract

FIELD: storage safety.

SUBSTANCE: invention is related to ensuring the safety of storage and transportation of petroleum products, in particular by rail. The proposed technical solution includes placement of the adsorbent between two membranes, which are grids of a flame retardant made of basalt fabric, fixed on the rims. The membranes are installed in the grooves of the adsorption-venting valve bushing, which allows changing the distance between them, as well as the type of adsorbent used, while upon reaching the saturation limit of the adsorbent, the valve bushing is removed through the hatch, the upper membrane is removed and the adsorbent is replaced.

EFFECT: invention can be used to reduce losses of petroleum products due to evaporation, as well as to improve environmental and fire safety.

1 cl, 1 dwg, 2 tbl

Description

The invention relates to the field of ensuring the safety of storage and transportation of petroleum products, in particular by rail, and can be used to reduce losses of petroleum products due to evaporation, as well as to improve environmental and fire safety.

Breathing devices serve to maintain a constant pressure in the free space of the tank when filling and draining oil products, when the temperature of the gas medium changes, and also to ensure tightness when the tank capsizes; to prevent explosion and fire hazardous situations, they are equipped with flame arresters operating on the principle of extinguishing a flame in narrow channels.

The following devices are accepted as analogues: 1) a breathing valve for tanks with volatile liquids, containing a body with gates for passage and exit from the tank of air and gas-air mixture, the lower part of the body is made in the form of a truncated pyramid, facing downwards with a smaller base, while the valve body in the lower part it is equipped with additional gates for the passage of air into the tank, and the angle of inclination of the walls of the pyramid is chosen so that the area of the latter exceeds the area of their horizontal projections by at least two times, characterized in that the gates for the passage of air are equipped with main and additional flexible connections, each of which is attached at one end to the central part of the outer side of the valve, and at the other end to the inner wall of the seat pipe, the main flexible connections being made in the form of plates, and the additional ones in the form of chains (patent RU 32475 U1, 20.09.2003);

2) a breather-safety valve for oil tanks, containing a body with pressure valves and vacuum valves, each of which includes a seat made on the body and a plate placed on the seat with the possibility of movement, characterized in that the plates, identical in purpose, are made of different weights (patent RU 45172 U1, 04/27/2005);

3) a breathing valve for tanks with volatile liquids with breathing into an open system, containing a housing, on one axis of which there is a vacuum plate loaded with a spring, and a pressure plate having holes for interacting with the vacuum plate, characterized in that the pressure plate, combined with load, installed in the guides and, being at the same time the seat of the vacuum plate, loaded statically by the gravity of the load, and the body simultaneously serves as the seat of the pressure plate (patent RU 91125 U1, 27.01.2010);

4) a breathing valve, including a flame arrester installed in the upper part of the valve under the cover, pressure and vacuum gates located in the valve body, characterized in that the valve body is enclosed in a protective casing, the pressure gate is installed in the lower part of the valve body, and the valve cover is equipped with , at least one swivel bracket (patent RU 101136 U1, 01/10/2011);

5) a breathing valve containing a valve body, a valve disc and a valve actuation indicator fixed on the body, characterized in that the respiratory valve contains a valve actuation indicator cavity isolated by the valve disc from the gas space of the reservoir and the atmosphere when the disc is located on the valve seat and communicating with the gas space of the tank and the atmosphere in case of valve actuation when the valve disc is lifted from the valve seat (patent RU 136517 U1, 01/10/2014).

Common disadvantages for the listed analogues are the complexity of the design and the leakage of oil vapor into the environment.

An adsorption-breathing valve (patent RU 192622 U1, 09/24/2019) was chosen as a prototype, consisting of a body with two nozzles, inside of which a fire arrester is placed, characterized in that the fire arrester consists of two elastic meshes based on basalt fabric with a certain cell size, providing extinguishing of the flame, between which is placed sibunit, designed to adsorb vapors of petroleum products, which prevents their release into the atmosphere, as well as the spread of the flame.

The disadvantage of this valve is the difficulty of replacing the adsorbent upon reaching its saturation limit.

The proposed technical solution provides for the placement of the adsorbent between two membranes, which are grids of a flame retardant made of basalt fabric, fixed on the rims. The membranes are installed in the grooves of the adsorption-breathing valve sleeve, which allows you to change the distance between them, as well as the type of adsorbent used.

Upon reaching the saturation limit of the adsorbent, the valve sleeve is removed through the hatch, the upper membrane is removed and the adsorbent is replaced.

Nets based on basalt fabric have high fire resistance, simple design, low cost, high mechanical characteristics, chemical resistance, which allows them to be used as a fire arrester. To substantiate the possibility of using basalt fabric as a mesh flame arrester, the calculation of the critical diameter of the flame-extinguishing element (KDPE) for kerosene TS-1 was carried out, the safe and equivalent diameters were determined; fire tests were carried out.

The critical diameter of the flame-extinguishing element channel is calculated by the formula:

where Re is the Peclet number;

R is the universal gas constant kJ/mol ⋅ K;

T is the initial temperature of the gas combustible mixture, K;

λ is the thermal conductivity of the combustible mixture, W/(m ⋅ K);

S _u - normal flame propagation speed, m/s;

C _p is the heat capacity of the combustible gas mixture at constant pressure, kJ/(kg ⋅ K);

P is the pressure of the combustible mixture, Pa;

M is the molar mass of the combustible mixture, kg/mol.

The safe diameter of the channel of the flame extinguishing element is taken taking into account the double safety factor, that is:

d _without \u003d 0.5d _cr

The size of a square cell (a) of a grid based on basalt fabric is determined by the formula:

where r _g - hydraulic radius, mm;

S - cell area, mm ² ;

П - cell perimeter, mm.

The calculation results are shown in Table 1.

To confirm the possibility of using a basalt grid as a flame arrester, fire tests were carried out. Rectangular basalt tissue samples were made with a size of 0.25 × 0.25 m. Holes were made in the fabric between the fibers, corresponding to the calculated data (diameter 1.37 mm for gasoline). After that, the fabric was fixed in a ring-shaped holder with an inner diameter of 0.20 m. The air temperature in the room was 20-25°C. Gasoline was poured into a metal pan and set on fire. With the help of the holder, the source of ignition was covered with a fire-fighting agent. At the same time, the persistent fiery combustion ceased instantly, and there was no emission of smoke.

As a sorbent located between elastic basalt networks, materials based on active carbons with a high specific surface area and sorption capacity, for example, sibunit, can be used. The physicochemical properties of sibunite compared to activated carbons are shown in Table 2.

The figure 1 shows a diagram of the adsorption-breathing valve. It consists of a body 1, which contains a sleeve 2, equipped with grooves 3; membranes are installed in the grooves, which are fixed on the rims 5 of the grid of the flame arrester made of basalt fabric 4; a layer of adsorbent 6 is placed between the membranes. A hatch 7 is provided in the valve body to remove the sleeve.

Claims (1)

Adsorption-breathing valve, characterized in that it consists of a body in which a sleeve is placed, equipped with grooves in which membranes are installed, which are grids of a fire arrester made of basalt fabric, fixed on the rims, an adsorbent is placed between the two membranes, while the upper membrane is removable , which allows you to change the distance between the membranes, as well as the type of adsorbent used.

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