Many people know about the "West-East Gas Transmission Project", but this time it is the "West-East Hydrogen Transmission Project"

Jiang Yue

On July 3, the survey and design of the Kangbao to Caofeidian hydrogen pipeline project in Hebei Province was launched. The pipeline is expected to be 972.7 kilometers long, with a diameter of 813 mm and a maximum annual output of about 1.3 million tons of green hydrogen. The pipeline will transport green hydrogen produced in Inner Mongolia and other regions to Beijing and Tangshan to meet the hydrogen needs of the two places, which will effectively solve the problem of environmental pollution and meet the needs of energy conservation and emission reduction.

Hydrogen transportation is different from coal and natural gas transportation. People are already familiar with "transporting coal from the north to the south" and "transporting gas from the west to the east". These grand projects promoted at the national level mainly solve the problem of uneven energy distribution in my country. They deliver coal and natural gas to areas that are "short of coal" and "short of gas" through "express delivery to home", so that all parts of the country can enjoy the same high-quality resources. However, the "express delivery items" of the above projects are not "green" from an energy perspective, because coal and natural gas will produce carbon dioxide during use.

Compared with traditional energy sources such as coal, oil, and natural gas, hydrogen is "odorless and non-toxic" during use, and only produces water after being used as energy, which can completely achieve "zero emissions". Currently, hydrogen is divided into gray hydrogen, blue hydrogen, and green hydrogen according to the degree of emissions during the production process.

Gray hydrogen refers to hydrogen produced from fossil fuels. Currently, my country's hydrogen production mainly comes from this method. Coke and chlor-alkali will produce hydrogen during the normal production process. If it is not collected, the hydrogen will be wasted. Therefore, hydrogen can be obtained by separating and purifying the waste gas from the coke and chlor-alkali industries. This method of collecting hydrogen is also called "industrial by-product hydrogen."

Blue hydrogen is low-carbon hydrogen produced after gray hydrogen is processed with carbon capture and storage technology during production. Green hydrogen, on the other hand, is produced through an electrolysis process, using renewable energy sources such as wind, solar, and electricity, and can achieve zero carbon emissions during production, but at a high economic cost.

From the definition of these types of hydrogen, only green hydrogen can truly achieve "zero emissions" throughout the production and use process, but it needs to rely on renewable energy such as wind and solar energy, and my country's wind and solar energy are mainly distributed in the vast western region. At present, a number of photovoltaic and wind power green hydrogen production projects have been built in Xinjiang and Inner Mongolia, etc., to transport green hydrogen from the west to the economically developed areas in the east of my country. This is the "West-to-East Hydrogen Delivery" demonstration project.

It is called a "demonstration project" because the project has just started small-scale construction. The starting point is in Ulanqab City, Inner Mongolia Autonomous Region. Green hydrogen is produced in the city and then transported to Yanshan Petrochemical in Fangshan District, Beijing through a hydrogen pipeline of more than 400 kilometers. This is my country's first large-scale, long-distance, cross-provincial pure hydrogen pipeline. In a few years, this hydrogen pipeline may continue to extend to more green hydrogen production bases in western my country and to more economic development hinterlands in the east.

In the future, we may be able to use hydrogen from western my country more conveniently, just like turning on the stove at home to use natural gas. This hydrogen will be transported to various hydrogen refueling stations in the eastern region, providing energy for tens of thousands of hydrogen fuel cell vehicles in the city. In the future, cities will be free from the unpleasant car exhaust; in large factories such as steel, chemical, and petrochemical, hydrogen will gradually replace fossil energy such as coal to achieve low-carbon emissions in industrial production; hydrogen may be used as the main energy source for urban power generation, replacing coal-fired power plants and natural gas power plants.

The construction of the "West-to-East Hydrogen Transmission Project" also faces many difficulties: to achieve efficient transportation, the pipeline pressure needs to be increased, but my country currently lacks experience in building such high-pressure pipelines; hydrogen is different from natural gas, the "hydrogen embrittlement" phenomenon it produces can cause the material to suddenly break, causing serious accidents and losses, so when designing materials, it is necessary to fully guard against the risks brought by "hydrogen embrittlement"; hydrogen is a flammable and explosive gas. If a leak occurs during transportation, it is very easy to explode when encountering sparks in a confined space.

When the West-East Gas Transmission Project, which runs across nine provinces and regions and has a total length of 4,200 kilometers, was launched, it encountered many difficulties during construction. However, after 20 years of construction, it has now become a landmark project for the development of western my country. Currently, my country's West-East Hydrogen Transmission Project is under construction. In the future, as the application of hydrogen energy expands and the construction mileage gradually increases, it will become another important cross-regional resource allocation project in my country.

(The author is a member of the Beijing Science and Technology Popular Science Lecture Team and an engineer at the Institute of Intelligent Equipment of the Beijing Academy of Science and Technology)