Inert gas replacement cleaning standard for propylene oxide transport tanker?

Propylene oxide is an important chemical raw material, because of its flammable, explosive and toxic characteristics, the risk must be strictly controlled during transportation. In particular, the use of inert gas is a common measure during the cleaning and replacement of propylene oxide transport tanker. This paper will analyze the inert gas replacement cleaning standard of propylene oxide tanker in detail, and discuss the relevant operation specifications and safety precautions.

1. PROPYEPOXY PROPANE TRANSPORTATION TANK CHARACTERISTICS

Propylene oxide (Propylene oxide) is a colorless, flammable, toxic liquid with a strong pungent odor. Its flammability is mainly manifested in the wide range of explosion limits in the air, and it is easy to cause explosion under the action of high temperature, open flame or static electricity. Therefore, in the process of transportation, strict protective measures must be taken to avoid accidents caused by improper operation.

As the main transportation means of propylene oxide, the tank car usually adopts the design of pressure vessel, and the interior is specially treated to ensure the safety of transportation. Due to the special nature of propylene oxide, after loading and unloading, a certain amount of propylene oxide gas or liquid is often left inside the tanker. If these residual substances are not cleaned and replaced in time, it will bring great safety hazards. Therefore, inert gas replacement cleaning has become an important part of ensuring the safe reuse of tanker.

2. of Inert Gas Displacement Cleaning Necessity

Inert gas is a gas that is chemically stable and difficult to react with other substances, such as nitrogen, carbon dioxide, argon, etc. In the cleaning process of propylene oxide transport tanker, the main function of inert gas is to reduce the concentration of residual propylene oxide gas in the tanker to a safe level through filling and replacement, so as to avoid explosion or poisoning accidents caused by the accumulation of residual gas.

Specifically, inert gas replacement cleaning can effectively isolate the oxygen in the air and prevent the mixture of propylene oxide and air from reaching the explosion limit. Inert gas can also reduce the temperature in the tank car, reduce the pressure fluctuation caused by thermal expansion and contraction, so as to further improve the transportation safety.

3. Propylene Oxide Transport Tanker Inert Gas Displacement Cleaning

In order to ensure the safety and efficiency of the cleaning and replacement process of the propylene oxide transport tank car, the industry standard has made clear provisions on the selection of inert gas, replacement process and detection methods. The following are the specific replacement cleaning standards:

1. Inert gas selection standard

When choosing an inert gas, it is necessary to consider its chemical stability, density and economy. Carbon dioxide and nitrogen are the more commonly used inert gases because they are denser, can effectively cover the bottom of the tank car, and are relatively low cost. It should be noted that although the density of argon is higher, its cost is also higher, so in practical applications, carbon dioxide and nitrogen are more common.

2. Replacement process standard

The inert gas replacement cleaning of the propylene oxide transport tank usually includes the following steps: (1) Empty the residual gas: Before starting the replacement, it is necessary to empty the residual propylene oxide gas in the tank as much as possible. This can be done by natural ventilation, mechanical ventilation or forced exhaust. (2) Inert gas filling: After ensuring that the concentration of propylene oxide in the air in the tank car drops to a safe level, start to inject inert gas into the tank car. During the injection process, the flow rate and pressure of the inert gas need to be controlled to ensure that the gas can be evenly distributed. (3) Gas replacement detection: After the replacement is completed, use professional testing equipment to detect the gas composition in the tank to ensure that the concentration of propylene oxide is lower than the dangerous value. (4) Residue treatment: If it is detected that the concentration of propylene oxide exceeds the standard, it needs to be replaced and cleaned again until the concentration drops to a safe range.

3. Safety testing standards

In order to ensure the effectiveness of the replacement cleaning, the gas environment inside the tank car must be strictly tested. Specifically include: (1) propylene oxide concentration detection: use portable gas detector or other special equipment to measure the concentration of propylene oxide in the tank. According to the relevant standards, the explosion limit of propylene oxide is usually 3% ~ 30% (volume ratio), so after replacement cleaning, the concentration of propylene oxide in the tank should be less than 0.5 (volume ratio). (2) Oxygen concentration detection: After injecting inert gas, the oxygen concentration in the tanker should be reduced to less than 1% to ensure complete isolation of air and avoid explosion caused by mixing of propylene oxide and oxygen. (3) Pressure detection: During the replacement process, it is also necessary to monitor the pressure inside the tank to ensure that the pressure is within a safe range and avoid equipment damage caused by overpressure or negative pressure.

4. Operation Precautions

In actual operation, the following precautions shall be strictly observed for inert gas replacement cleaning of propylene oxide tanker: (1) Operators must undergo professional training and be familiar with the process and precautions of replacement cleaning. (2) During the replacement process, a warning area shall be set around the tanker to prohibit irrelevant personnel from entering. (3) The inert gas used should meet the quality standards to avoid the influence of gas impurities on the replacement effect. (4) When detecting the gas concentration, calibrated equipment should be used and operated in strict accordance with the testing procedures.

5. summary

Inert gas replacement cleaning of propylene oxide tanker is an important link to ensure transportation safety. By selecting the appropriate inert gas, following the standard replacement process, and strictly implementing the safety inspection standards, the concentration of propylene oxide in the tanker can be effectively reduced, the oxygen in the air can be isolated, and the explosion and poisoning accidents can be avoided. The operator must have professional knowledge and skills to ensure the safety and reliability of the replacement cleaning process. Safe, efficient and sustainable transport of propylene oxide can only be achieved if the relevant standards are strictly followed.