Introduction to the Development of Natural Gas Odorizing Equipment

As a safety precaution technology, gas odorization is widely used in gas and toxic and odorless gas leak detection. Especially in European and American countries and Japan, there is a form of regulations to restrict gas companies, odorant manufacturers and intermediate suppliers. Although this technology has been used in China for a long time, many people still do not know much about its theoretical origins and the importance of its development and application, as well as the composition, principle, application, maintenance, and safety management of odorizing equipment. Understand, lack of understanding. Today I would like to take this opportunity to share some insights with experts and colleagues in order to enhance our understanding of this technology and raise the awareness of the industry and the public about the importance of gas safety precautions. This article elaborates on the following aspects:

1. Overview of the development of odorization technology

At the beginning of the last century, many countries began to use artificial gas (artificial gas), which has a strong smell, which is caused by by-products (by-products) of the manufacturing process. This smell indicates "a leak". However, in the subsequent development and utilization of natural gas, natural gas is colorless and odorless. Even if it has odor, due to environmental protection requirements, harmful sulfides (hydrogen sulfide, methyl or ethyl mercaptan, etc.) must be removed before use. , when replacing artificial gas with this gas, it is recognized that an alert agent is needed.

In the 1960s, foreign countries completed a comprehensive conversion from artificial gas to natural gas and pipeline liquefied gas. Since the by-products of artificial gas itself have strong odors during the production process, while natural gas and pipeline liquefied gas are odorless or slightly odorless gases, they lose their warning function once leaked, so research on odorants and odorizing devices began to be explored. . The research and application of this technology in some developed countries is already very mature.

Spurred by World War II, new chemical processes and chemicals were developed. After years of research into various chemicals as odorants, low molecular weight heavy branched alkyl mercaptans, alkyl sulfides and cyclic sulfides have emerged as the preferred odorant compounds.

Domestic current situation:

The application of natural gas in my country basically began in the 1980s, and was developed and utilized on a large scale at the beginning of this century. The gas odorization technology that followed has also made great progress and matured. With the help of odorization technology from developed countries and combined with domestic traditional experience, a unique odorization technology theory system has been formed. In less than 30 years, with the joint efforts of colleagues in the industry, standards for gas odorization concentration and the industry standard "Technical Regulations for Urban Gas Odorization" for odorization devices have been formulated, and various manufacturers have developed various types of odorization devices that meet the needs of different users. Whether in terms of reliability, odorization accuracy, safety and environmental protection, the odorization devices have reached the international advanced level.

2. Formation and determination of odorization standards

People have known for a long time that sulfide mercaptans and the like have a nauseating and strong pungent smell, so the original odorants mostly used mixtures of sulfides and mercaptans. While foreign countries are studying odorizing technology, they have also developed and produced odorants, the representative one is THT (tetrahydrothiophene). Sulfur is harmful, both to animals and plants. Gas should be odorized, but how much odorant should be added to achieve an appropriate ratio is a question worth discussing, because the advantage of adding a suitable odorant dose is that 

① it can quickly detect leaks Alarm to nip problems in the bud; 

② Solve environmental pollution problems and avoid harm to human body; 

③ Reduce operating costs of gas companies.

How are standards set and ratios determined?

The first and most effective experiment is this. In an experimental room, a group of experimental testers are gathered and the odorant is slowly released into the experimental room. Everyone who detects the smell of the odorant can leave. When the proportion of people who are aware of it accounts for 97.3% of the people tested, a gas sample is taken to analyze the odorant concentration, and the concentration obtained by converting this concentration into gas is used as the odorizing standard. Use this standard concentration to odorize gas, and repeatedly verify the above test data, and the conclusions drawn can basically be implemented as standards. The current standards set by various countries, whether based on the conclusions of others or their own experiments, for THT, are between 16 and 24 mg/m3, while thiols and sulfides are between 4 and 9 mg/m3. Such a standard The reason why quantity is effective is obvious, that is, the user's (human) awareness is decisive. With the in-depth development of sensing technology, it is now possible to automatically monitor gas leaks. However, among a wide range of users, the proportion of households is huge, and the human sense of smell is still the most basic sensor.