Hydrogen blending of natural gas widens deep decarbonization road

"Promote the construction of zero-coal cities. By 2030, we will pilot low-carbon technologies such as mixing natural gas with hydrogen in gas-fired power generation and heating." The "Chongming World-class Ecological Island Carbon neutral Demonstration Zone Construction Implementation Plan (2022 version)" issued recently proposed the above key tasks, and Shanghai Chongming became the first region to clarify the time point of hydrogen mixing of natural gas, causing concern in the industry.

Mixing natural gas with hydrogen can not only expand the application scenario of hydrogen energy, but also improve the combustion performance of terminal equipment, reduce carbon dioxide, nitrogen oxides and other emissions, and green and low-carbon characteristics make it more and more popular. According to Peng Suping, an academician of the Chinese Academy of Engineering, the team predicts that if the proportion of hydrogen mixing is 10%-20% and the life cycle cost of "production, storage and transportation" is calculated (30 yuan/kg), the output value of the whole industry chain will reach 80-180 billion yuan/year. In the face of broad market prospects, how to seize the development opportunities?

■■ Provide new ideas for carbon reduction

Among the many hydrogen-related technologies, the popularity of hydrogen blending of natural gas is not accidental.

"The integrated development of the two is an important choice to achieve deep decarbonization." At the 18th China Distributed Energy International Forum held recently, Zhu Xingshan, deputy chief economist of the Development Planning Department of China National Petroleum Corporation, said that the addition of hydrogen to natural gas is equivalent to an increase in supply, which will greatly reduce carbon emission intensity while easing the pressure on the latter supply. At present, hydrogen energy storage and transportation is still a "stuck neck" link, and mixing is conducive to the low-cost storage and transportation of hydrogen and large-scale utilization. "Natural gas and hydrogen energy have similar characteristics in the transport, transport, use and other industrial chain links, and can find a lot of integration opportunities in power generation, construction industry and other application scenarios."

Wang Hongjian, chief engineer of Daoshi Research Institute of Beijing Gas Thermal Engineering Design Institute, further confirmed: calculated at 10%-20% hydrogen mixing ratio, the carbon emission reduction of equal calorific value is 3.5%-7.6%; Making full use of the existing gas pipeline network infrastructure, the cost of large-scale and long-distance hydrogen transport is 0.3-0.8 yuan/kg per 100 kilometers. "Since the international research began in 2000, there are more than 40 demonstration projects around the world, and about 2,900 tons of hydrogen are incorporated into the natural gas pipeline network every year, and the proportion of hydrogen is up to 20%." In China, as the hydrogen energy medium - and long-term plan is clearly proposed, pilot demonstrations such as hydrogen-doped natural gas pipelines are carried out, and research work and demonstration demonstrations are accelerated."

In addition to the regional level, some enterprises are also trying first. The reporter learned from the State Power Investment that Jingmen Green Movement Energy Co., LTD., a subsidiary of the group, successfully achieved 30% hydrogen-doped combustion transformation and operation at the end of September. This is the first time that China has carried out high-proportion hydrogen-doped combustion transformation tests and scientific research on heavy-duty gas turbine commercial units, and it is also the first demonstration project in the world to carry out high-proportion hydrogen-doped combustion in natural gas combined cycle and cogeneration commercial units. Only a 54 MW gas turbine in Jingmen can reduce carbon dioxide emissions by more than 18,000 tons per year with 30% hydrogen mixing.

■■ The industry is still in its infancy

The value is widely recognized, but there is still a long way to go to really mix natural gas with hydrogen. Zhang Bo, a professor at the China Institute of Energy Policy at Xiamen University, said that although some provinces have issued local plans as a breakthrough in hydrogen energy storage and transportation and terminal applications, the national level has not yet issued development plans, and the industry as a whole is still in its infancy.

"This is a complex system engineering, both to consider the technical feasibility, but also subject to safety, economic constraints." Some key issues must be addressed before it can be used on a large scale." Zhang Bo said that taking safety as an example, compared with methane, the main component of natural gas, hydrogen has a larger explosion limit range, is more likely to leak spontaneous combustion, and the risk of explosion after mixing is correspondingly expanded, which puts forward higher requirements for natural gas long-distance pipelines, urban gas pipe networks and terminal energy use equipment. It is important to study the law of leakage diffusion and safety risk control of hydrogen-doped natural gas.