How to determine the size of the vent in the storage tank, container and other equipment

The size of the vent on storage tanks, containers and other equipment needs to be determined according to the volume of the equipment, the use environment, the nature of the medium and other factors.

First of all, the size of the vent should be able to meet the discharge needs of the gas or liquid generated by the equipment during normal use, so as to ensure the normal operation of the equipment. Secondly, the size of the vent should also take into account the safety of the equipment, so as to avoid the internal pressure of the equipment being too high due to the small vent, which will cause safety accidents.

When determining the size of the vent, it is also necessary to consider the environment in which the equipment will be used. For example, if the device is used in a high-temperature environment, the size of the vent should be larger than when used at room temperature to allow for faster heat and gas discharge. In addition, the nature of the medium is also an important factor in determining the size of the vent.

For example, if the medium is volatile or flammable, the size of the vent should be larger than that of other media, so as to discharge harmful gases more quickly and avoid causing safety accidents such as fire or **.

In short, determining the size of the vent on storage tanks, containers and other equipment needs to consider a variety of factors to ensure the normal operation and safety of the equipment.

Generally, it is DN250 DN300, which can be determined by referring to SYT Petroleum Storage Tank Accessories Part 3: Automatic Breather Valve Standards.

In some pressure vessels, the safety valve interface needs to be set, how to determine the size of the interface diameter? Specific: equipment import medium - high temperature water; Outlet medium – water (upper), sewage (lower). Find out more.

Depending on the maximum flow rate or the flow generated by the pressure source in the event of a possible accident. Check the specifications of the safety valve manufacturer according to the flow rate and the selected form (different manufacturers). If calculated as a general rule:

The nozzle diameter is calculated according to the flow rate and protection pressure, and then the diameter of the nozzle is 2 gears larger (1 gear larger for liquid medium) according to the diameter of the nozzle, and the diameter series is 10, 15, 20, 25, 32, 40, 50, 65, 80, 100, 125, 150, 200, etc.

1. When the container is equipped with a safety valve.

Considering the lag of the opening action of the safety valve, the container cannot be relieved in time, and the design pressure shall not be lower than the opening pressure of the safety valve. The opening pressure refers to the instantaneous pressure at which the disc begins to rise under operating conditions and the medium is continuously discharged, and its value is less than or equal to (times the working pressure of the vessel.

2. When the container is equipped with a rupture disc.

The design pressure must not be lower than the burst pressure of the rupture disc. The value can be determined according to the type of rupture disc, taking the design burst pressure of the rupture disc plus the upper limit of the selected rupture disc manufacturing range, which is usually taken (times the maximum working pressure.

3. When a safety valve is installed on the pipeline on the outlet side of the container.

The design pressure should not be lower than the opening pressure of the safety valve plus the pressure drop from the vessel to the safety valve.

Fourth, when the container inlet pipeline is equipped with a safety valve.

When the outlet side is equipped with a shut-off valve or other shut-off device, the design pressure shall be greater than the following two cases.

1. The opening pressure of the safety valve.

2. Increase the appropriate margin according to the working pressure of the container.

5. When the container is located on the inlet side of the pump and there is no safety control device.

Take the design pressure when there is no safety relief device, and check the external pressure.

The design pressure is the greater of the following three.

1. The normal working head of the pump is doubled by the normal inlet pressure of the pump.

2. The maximum inlet pressure of the pump plus the normal working head of the pump.

3. The normal inlet pressure of the pump plus the closing head (that is, the full closing head of the pump outlet).

6. When there is a control device in the container system and a single container does not, and the pressure drop between the containers is difficult to determine, the design pressure can be determined in the following table.

This needs to be categorized to determine:

1.If it is a cylindrical container with a volume greater than 500L, the design temperature is 350 and the design pressure is between "and ".

2.If it is a vertical cylindrical storage tank, the volume is 20 to 10000m3, the design temperature is -20 to 250, and the design pressure is -500p to 2000pa.

3.If it is a rectangular container, the pressure is designed with the connected atmosphere as the design pressure, and the volume is not limited.

4.In the case of cylindrical silos, the temperature does not exceed 100 °C, and the design pressure is -500Pa to 2000Pa.

Generally, the design pressure is higher than the working pressure.

The PP plastic storage tank used to put hydrochloric acid is a common chemical storage container, which has excellent upshift properties such as corrosion resistance, high temperature resistance, and pressure resistance, and is widely used in chemical, pharmaceutical, food and other industries. However, there are some safety issues that we need to pay attention to during use, especially when venting.

Venting is the discharge of chemicals from a storage tank for cleaning, maintenance, or replacement. In the venting process, due to the different properties of chemicals, toxic and harmful gases may be produced, and the lifting and grinding will cause harm to the human body and the environment. Therefore, we need to take some measures to ensure the safety of the venting.

A common method is to use a water seal. Water seal refers to the setting of a water seal device at the vent of the storage tank, which connects the venting pipe with the water seal, so that the air vent body is absorbed by water when passing through the water seal, so as to achieve the purpose of purifying the air. The advantages of water seals are that they are simple and easy to implement, low cost, and can effectively purify gases and protect the environment and human health.

However, the use of water seals also has some problems with quarrels. First of all, the water seal needs to be replaced regularly, otherwise it will lead to water quality deterioration and affect the purification effect. Secondly, the water seal needs to maintain a certain water level, otherwise it will lose its purification effect.

Finally, the water seal only purifies the gas and does not play a role in the discharge of the liquid.

Therefore, we need to pay attention to the following points when using water seals:

1.Choose the right water seal device to ensure that its quality and performance meet the requirements.

2.Change the water regularly and keep it clean.

3.Maintain the water level of the water seal to ensure the purification effect.

4.For liquid discharge, other measures are required, such as the use of pumps or inverted storage tanks.

In conclusion, the use of water seals is an effective venting safety measure, but it is necessary to pay attention to its limitations and usage methods to ensure the safety and environmental protection of the venting process.

I also went to Zhonghuan Chemical to ask, and it is indeed not very safe.

The hollow mouth of the plastic storage tank must not be water-sealed, if there is a water seal, the improper operation of the worker can easily cause the plastic storage tank to be sucked up. It turns out that we have been using water seals, and there have been no problems for many years, but the last time we bought the equipment of Zhonghuan Chemical, their technicians were very resolute against our approach, and later after discussion, we changed the original practice. To our kind of chemical industry, once there is a problem, it will not be a small problem, everything must be cautious!

The hollow port of the polypropylene storage tank must not be water-sealed, if there is a water seal, the improper operation of the worker can easily cause the polypropylene storage tank to be sucked up.

Some people have operated, there is no big problem for the time being, but it is recommended that the polypropylene storage tank is not water-sealed, if there is a water seal, the worker does not operate properly, and it is easy to cause the polypropylene storage tank to be stuffy and broken.