Qin Chao Kwai, Gas Institute of Tongji University: How to make the gas pipeline safer

Qin Chao Kwai, director of the Gas of the University of Tongji University, executive director of the China Urban Gas Association, and a member of the Shanghai hidden danger pipeline investigation and reconstruction class, believes that the current level of construction management of urban gas pipelines, including the standardization of processes, management of graphics, and targeted design. All need to be strengthened. In addition, improving the overall safety level of the gas industry is simply the talent training and knowledge system.

Author: Fu Xiaoyin

Figure: Tuwa Creative

On July 12, the National Development and Reform Commission released the "Fourteenth Five -Year Plan" New Urbanization Implementation Plan ", which was proposed in promoting the construction of new cities. Gas pipelines, gas field stations, residents' household facilities and monitoring facilities with hidden safety hazards.

Earlier, whether in the high -quality development conference of housing and urban and rural construction in February, or in the "National New Town and Urban -Rural Introduction Development Mission 2022" issued by the National Development and Reform Commission in March, the aging update and transformation of gas pipelines was carried out Line is the main work content of 2022.

As of now, many provinces and autonomous regions such as Guangxi, Shandong, Shaanxi, Hebei, and other provinces have successively released the task of renewal the gas pipeline renewal in 2022. The Ministry of Housing and Urban -Rural Development will coordinate the construction of about 20,000 kilometers with hidden safety hazards this year. During the "14th Five -Year Plan" period, the old gas pipeline was transformed by about 100,000 kilometers.

With the importance of the old gas pipeline update, the next question is how to change and how to establish a more secure urban gas pipeline management system? Qin Chaoki, director of the Tongji University Institute of Gas Gas, executive director of the China Urban Gas Association, and a member of the Shanghai hidden danger pipeline investigation and reconstruction class, said that the current level of construction and management of urban gas pipelines, including the standardization of the process, the management of the graphic, and the targeted design, the design, and the targeted design. All need to be strengthened. In addition, improving the overall safety level of the gas industry is simply the talent training and knowledge system.

The following is an exclusive interview with the Economic Observation Network:

Economic Observation Network: How did China's urban gas pipeline construction develop? How many stages are divided?

Qin Dynasty Aoi: This has something to do with the development history of the urban gas industry. The large -scale development has roughly experienced three stages. The first stage was artificial gas. The earliest city in China was Shanghai. In 1865, the "British tap fire house" used gas -based technology to produce gas, and then paved pipelines, but the scope was small at that time. After the founding of the People's Republic of China, large steel refining has made artificial gas develop faster in some large cities. At that time, the gas thermal value produced at that time was probably 1/5 to 1/3 of natural gas.

In the pipeline, the cast iron pipe is used in the artificial gas era. The cast iron pipes are divided into two types: gray -mouth cast iron and ball ink cast iron. In the era of artificial gas, the sealing method of cast iron pipes mostly adopts inheritance interfaces. Not big, so the pressure is not high, there is no problem in this way to keep sealing. In addition, this sealing method is suitable for artificial gas, because artificial gas contains certain moisture or macromolecular hydrocarbons, which can maintain the bloating of the sealing material and maintain sufficient pipeline gas.

In the second stage, in the mid -to -late 1980s to the mid -to -late 1990s, some cities in China built a small amount of liquefied petroleum supply pipelines and developed related pipeline technology, but the scale was not large. LNG mainly relies on steel cylinders to transport and distribute. Natural gas resources such as Chongqing and Chengdu, such as Chongqing and Chengdu, have been using natural gas.

In the third stage, with the east of the west gas in 2004, more and more cities in China have begun to develop natural gas transmission and distribution systems, and the pipeline has also begun to change. According to their own infrastructure, each city updates the channels or builds a new natural gas pipeline.

There are two main types of natural gas pipelines, one is steel pipes used under high pressure. At the construction site, the steel pipe is welded by sections, and its pressure resistance and sealing are better than the cast iron pipe. However, during the construction of steel pipes, road excavation is required, and the construction cost is relatively high. In addition, steel pipes also have special requirements for corrosion resistance.

The second main use of the pipes are plastic pipes (in English, referred to as PE tube, that is, polyethylene tube). PE tube construction is simple, the caliber is not large, and the highest pressure can be afforded than the steel pipe, but the construction is fast, cost -effective, and not There is a problem of corrosion. Therefore, in the mid -low -pressure pipeline system operated by urban gas companies, PE pipes account for more and more. However, the problem of plastic pipes is low mechanical strength, fragile, and easily damaged by third parties.

To sum up, the current gas pipes in service include three categories: steel pipes, cast iron pipes and PE pipes. Among them, high -voltage and secondary high -pressure pipelines are basically steel pipes. Generally, it is under the operation and management of the company. Soon after these pipelines, the general state is much better than the pipeline operated by the Chengfan Company.

Economic Observation Network: How long is the use period of gas pipelines generally, what factors will affect its use period?

Qin Dynasty Aoi: Under normal circumstances, if no one is destroyed and the maintenance status is better, the pipeline life can even reach 50 years. Aging is only the physical cause of the pipeline life. Other influencing factors include the management level and the human level (third party destruction).

Different countries have different management concepts and technical systems.

For example, in Germany, if the design life of a certain pipeline is 30 years, it will strictly follow a set of technical systems to ensure that the pipeline runs safely in 30 years from materials, construction, acceptance, and later maintenance. The United States adopts another set of technical methods, called integrity management. First of all, the evaluation and establishment of the factors will affect the operation of the pipeline, such as 10 factors, and then regularly record and evaluate the 10 factors of a certain pipeline. Maintenance.

About 20 years ago, this management system was introduced to China, but we collected less basic data. For example, each section of pipelines in the United States should record 20 influencing factors in 100 meters. After the record is recorded, which factor is more influential, how to pay attention to it in the future, the domestic may be simplified to 10 or 8 factors, so the current domestic pipeline is complete. Sexual management still has room for improvement.

Economic Observation Network: What factors will affect the safe operation of the pipeline?

Qin Dynasty Aoi: Recently, a more scientific research we have done is about the impact of DC power on the subway, which is a kind of "electrochemical corrosion". This is a very typical issue with Chinese characteristics. Our team has conducted on -site testing and scientific research since 2006. The impact of subways in Shanghai, Hangzhou, Wuxi, Changsha, and Foshan has a great impact on gas pipelines. The subway is driven by 1500V DC electricity, and 100%insulation between the DC power distribution system and the earth cannot be achieved, so the gas pipeline near the subway will be affected by DC power. When the subway starts, DC electricity can reach 5 or 6,000 Anpei. If there are a few ampel electric leaks in the nearby gas pipelines near the 5 or 6,000 Anpei, it will cause the steel pipes with defective anti -corrosion layer to slowly dissolve into the soil. It is possible to corrode and cause gas leakage.

In response to this aspect, foreign approach is: Before the pipeline planning is laid, go to the field to measure the interference near the routing on the spot, and wherever the interference is strong, we will take targeted technical measures. In terms of monitoring, it is not only monitoring the pipeline body, but also the environment where it is located. If there are large buildings outside, will it bring some potential damage in mechanics? And the pH value of the soil, the degree of pH, and the conductivity. They will record these data to derive the possibility of electrical corrosion of the space where the pipeline is in the electrical chemical corrosion, and scoring evaluation.

Another factors such as changes in road appearance will also affect the pipeline. For example: 10 years ago, a pipeline was designed in accordance with the national standards at that time, and it was buried underground in a certain depth. However, the roads have widened in 10 years, and traffic has become larger, so the force of the pipeline is worse than before. There are many problems similar to this nature, which is one of the tasks of this hidden danger channel investigation.

Economic Observation Network: What are the implementation links for the update of old gas pipelines? What are the points and difficulties?

Qin Chaoki: The first is to evaluate first, and the evaluation clarifies which pipelines have hidden dangers. The second link is changed.

Different cities or different companies are facing different problems. For example, in some large cities, it is more difficult to obtain roads and municipal construction permits. Urban gas pipelines are basically laid along the road. The higher the road level, the larger the pipelines on the side and the higher the pressure. The country now encourages the update of old gas pipelines, so it should be easier than before.

The other is the problem of expenses. The central budget investment arrangement is 640 billion yuan, but after spreading it to various cities, how much it can be implemented is likely to be part of the gas company contributed and local financial capital contribution. Cheng Ran Company has a certain public service color. Many times the profit is not the first consideration. It is the first to ensure supply and security.

On the other hand, the development of Chengfan Company is inseparable from the consideration of profitability. They are very concerned about the increasing cost of pipeline updates and even the increase in the cost brought by the alarm. In the future, spending a hard time to renovate the pipeline, and fighting for local finance subsidies may be something that Chengfan Company has to face.

Economic Observation Network: What is the direction of the old gas pipeline of the city?

Qin Dynasty Aoi: The reasons for leakage of different pipelines are different. Some are because of aging, some because of mechanics, and some are because of electrochemical corrosion, and some are due to third parties. Different reasons, the response strategies of various cities may be divided into the primary and secondary.

Cities with comprehensive construction coordination mechanisms such as Shanghai, while underground pipeline units obtain construction permits, they can understand the situation of all peripheral related pipelines to avoid, so there are fewer third parties in these cities. In this case, they want to use plastic tubes to replace steel pipes that are vulnerable to electrochemical corrosion. Some cities do not have such a coordination mechanism, and the plastic tube looks fragile. In theory, no pipe is perfect and has applicable problems.

To be sure, after the old pipeline is updated, the safety level of gas pipelines will be greatly improved in all aspects. However, judging from some of the construction sites we have experienced, the level of construction management, including standardization and graphic management, needs to be strengthened.

A better approach, such as Shenzhen gas, starts electronically from the recording negative of the construction welding port, just like going to the hospital to make a film, record the state of the welding port. If you need to establish an exchange near the pipeline or pile in the future, you can study whether the welding port can be afforded according to the negatives and stress analysis. However, the current research in this area is relatively weak and less. At present, we first solve the problem of thick lines. The fine problems first put it first, so I think that the quality of the tube network after update will definitely increase a level compared to the past. What we currently encounter is the problems that foreign countries have encountered in the stage of natural gas development, and our technical accumulation, attention, the strength of related research on these issues, and the strength of related research, and the consideration of national conditions are relatively lacking.

For the gas industry, in fact, only two things are done well can this industry be better. The first is safety, because the gas pressure is high, so the gas company must first do a good job of safety in order to carry the task of transporting energy. In this way, the advantages of long -term storage and flexible deployment of gas energy can be highlighted. The second is to improve the efficiency of gas use. At present, most gas companies still adhere to the concept of "selling more gas and making money", and earn the intermediate difference between wholesale and retail. Most of the gas companies that pursue such business philosophy have closed down, and only the gas companies that serve the service survive.

Therefore, the gas company wants to cultivate the market, and it is profitable from services instead of the difference in gas selling. For example, domestic natural gas industry users, most of the energy efficiency is not high. Each creation of a certain output value consumes a lot of natural gas. Gas companies can help industrial users reduce natural gas consumption to reduce costs through energy -saving technology, and charge service fees. On the surface, gas companies have decreased their gas sales, but in fact, they can be profitable from the service to save money for industrial users. This profit will not decrease with the decrease in the amount of gas sales.

There are many similar gas companies abroad. For example, the previous French gas company and RWE in Germany made money by selling gas in the early days. Later, they soon transformed into comprehensive energy service providers. Now the main profit model is to provide users with technical services.

Economic Observation Network: Why can't we do so finely for the management of gas pipelines?

Qin Dynasty Aoi: Not all problems can be solved through technology and management. The safety of the gas pipeline network is simply the talent training and knowledge system.

In terms of talent training, the number of graduates in the direction of university gas in the past three years is far from meeting the talent needs of the city -burning industry. According to the survey of the China City Gas Association in June 2021, the annual demand for professional and technical personnel in the country ’s city -fire industry is about 3900 to 6,000, but in 2018, 2019, and 2020, the number of undergraduate graduates of universities in universities does not exceed 500. There are less than 100 masters each year, and doctoral students have graduated for three years. In the case of lack of existing colleges and universities, especially key colleges and universities, many urban -Ran companies can only learn safety knowledge and strengthen safety awareness through their own training. In addition, there are people who have lost the problem. The city burning industry has a lot of responsibility and heavy pressure. If the salary is not matched, there will be many people who change their careers.

Back to college education, the difficulty of enrollment of gas disciplines, and the decrease in the number of teachers. Talent training in my country's urban combustion industry mainly relies on two majors -the "construction environment and energy application engineering major" of comprehensive universities, and the "oil and gas storage and transportation project" of petroleum colleges (mainly serving the upstream of the industry and long -term project) Essence At present, there are only a dozen of "gas" in colleges and universities in the country of "Architectural Environment and Energy Application Engineering". In the gap between teachers, the teachers of gas direction of colleges and universities do not exceed 10, of which half of the universities are less than 4 of the gas teachers.

In general, whether it is national or technical policies, the current attention to the city burning industry is not enough. For example, we currently only have certificates and training for operators, such as pressure regulators and pipeline maintenance workers. They need to go to the post certificate. There is no higher -level registered engineer. There are registered power engineers and equipment engineers in the adjacent industries, but there are no such special industries such as gas.

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