China's biomass power generation research has made new breakthroughs, helping to achieve the "dual carbon" goal

  On December 19, news came from Yangzhou University: The research team of Dr. Wu Duoli of the school, funded by the National Natural Science Foundation of China and the Jiangsu Shuangchuang Ph.D. Project, aimed at high temperature corrosion of nickel-aluminum coating biomass by water vapor content. A key new breakthrough has been made in the systematic research on the impact of performance.

  A few days ago, the relevant research results have been published online in the international academic journal "Corrosion Science" of the discipline of materials corrosion, which will provide a more comprehensive scientific theoretical basis for subsequent protection measures for high temperature corrosion of biomass.

  As the most potential renewable energy source, biomass energy has become the fourth largest energy source after coal, oil and natural gas, and its development potential is huge.

The promotion and application of biomass power generation technology will be an effective technical way to achieve the "dual carbon" goal, and will play a major role in promoting the large-scale and efficient and clean utilization of my country's biomass resources.

  Wu Duoli introduced that at present, most of the research on high temperature corrosion of biomass is aimed at corrosive deposited salt, but the corrosion of boiler superheater pipes by water vapor in the actual working environment of biomass power plants cannot be ignored.

The research team conducted a systematic study on the influence of water vapor content on the high-temperature corrosion performance of nickel-aluminum coating biomass, and elaborated on the high-temperature corrosion mechanism of the coating under different water vapor content.

  The reporter learned that in response to key issues, the team first prepared a nickel-aluminum coating with good density and adhesion to the substrate by high-temperature aluminizing method, and then used the nickel-aluminum coating as an experimental sample and placed it in a simulated production. Corresponding experiments are carried out in equipment in high temperature and corrosive environments.

After the experiment, the corrosion samples were characterized by corrosion weight gain, X-ray diffractometer, scanning electron microscope and transmission electron microscope, and detailed and in-depth analysis of the characterization results.

  "During the corrosion experiment, the samples need to be taken out every 24 hours, weighed and coated with salt. The salt coating experiment requires purely manual operation. The amount of salt applied is 5 mg/cm², which is very fine, so the operation is difficult." Liu Su, a graduate student of the research team, said that during the salt coating process, the sample needs to be placed on a resistance furnace for heating to ensure that the salt solution is deposited on the surface of the sample in time.

  Wu Duoli told reporters that the final result of the experiment is still unknown, and it takes a lot of energy and time to analyze.

The team consulted a large number of documents and discussed and researched, and finally through a series of micro-reactions summary and reasoning, combined with the laws of thermodynamics, to find out the reasons for the experimental results, and then carried out an in-depth explanation of the high temperature corrosion mechanism of biomass under different conditions.

  The team’s research results show that under the condition of no water vapor, the coating exhibits excellent corrosion resistance, and a protective layer mainly composed of Al2O3 (alumina) phase is formed on the surface.

Chloride corrosion occurs in local areas, causing slight surface and intergranular corrosion.

Under the condition of water vapor, in addition to chloride corrosion, water vapor penetrates into the corrosion layer/coating interface and generates active chlorine, which further accelerates the corrosion process.

The increase in water vapor content will form a large amount of potassium aluminate on the surface of the coating, thereby inhibiting the generation of chlorine and reducing the consumption of oxide forming elements in the coating.

When the water vapor content is 15%, the intergranular corrosion of the coating is the most serious; when the water vapor content is 30%, the corrosion of the coating surface is the most serious.

  Wu Duoli believes that in the actual operation of biomass power plants, the water vapor in the biomass fuel can be controlled to achieve higher expectations for the high-temperature corrosion behavior of the coating, and promote the large-scale promotion of biomass power generation.

Therefore, this research has very broad development prospects, which can effectively improve the efficiency of biomass power generation, reduce carbon emissions, and help my country achieve the "dual carbon" goal.

  Our reporter Guo Guozhong, correspondent Guo Zhoupei and Zhang Ping