 |
Nitrogen oxides (NOx) are important environmental pollutants contained in the combustion gases of fossil fuels, mainly in the form of NO. Traditional methods for denitrification of flue gas consume large amounts of energy, present safety issues and cause secondary pollution. The nitrogen content in microalgal biomass is as high as 7-12% of the dry weight of cells, and its large-scale cultivation can utilize high concentrations of nitrogen oxides (NOx) in industrial flue gases. Through the cultivation of energy microalgae, not only NOx in industrial flue gas can be removed, environmental pollution can be reduced, but also biofuel feedstock can be provided to produce high value-added products (Zhang et al. 2014a; Chen et al. 2015; Zhu et Al.2016). Wang Qiang, a researcher at the Institute of Hydrobiology, Chinese Academy of Sciences, has cooperated with the Sinopec Research Institute of Petroleum and Chemical Engineering since 2011 and has carried out research on the application of energy microalgae in the biological flue gas denitrification of industrial flue gas. He has made a series of achievements.
Firstly, based on the requirement of high concentration of nitrite tolerance and adaptability for algae species in industrial flue gas biological denitrification, NOx-tolerant algae species screening was carried out. The study found that the tolerance of high-concentration NOx by different microalgae and algae species has interspecies specificity, while most Chlorella species have good tolerance to high concentrations of nitrite, and further physiological studies have found that Adaptation is achieved through three steps of stress, adaptation and utilization (Li et al. 2016).
Subsequently, through the use of self-invented high-efficiency photobioreactor (Chinese invention patent, authorization number 201410063589.X), the biological denitrification capacity of Chlorella under industrial NOx environment was verified, and high biomass and cell oil content were obtained. At the same time, achieving a denitrification rate of 60% in flue gas proves the potential application value of microalgae in the field of biological flue gas denitrification (Zhang et al. 2014b). A joint production process Ver1.0 (Chinese invention patent, authorization number 201410063243.X) for microalgae biological denitrification, production of high value-added products and biodiesel production was proposed.
In view of the mismatch between the relative inefficiency of microalgae photoautotrophic growth and the high demand for industrial flue gas emission reduction, further studies have been conducted on the use of phototrophic and communal culture methods for flue gas biological denitrification by gradually optimizing the culture process. The maximum biomass yield of 9.87 g L−1 d−1 was obtained. At the same time the denitration rate was over 96%, the oil yield of 1.83 g L−1 d−1 was obtained. Studies have shown that the simultaneous absorption of organic and inorganic carbon in the co-cultivation culture process can significantly reduce the cost of organic carbon feedstock consumption. At the same time, at the end of the combined culture of microalgae biological denitrification, there are only trace nutrients in the culture fluid. It is the residue of organic carbon and carbon, and it achieves a green production process that avoids secondary pollution. This study demonstrated the feasibility of applying energy microalgae for industrial flue gas biological denitrification and energy production, and at the same time provided an industrialization strategy for flue gas emission reduction under limited land conditions (Chen et al. 2016). On this basis, the joint production process of microalgae biological denitrification, production of high value-added products and biodiesel production was further improved, and an optimized production process Ver2.0 was proposed.
The above two research results published in Environmental science & technology (Zhang et al. 2014b; Chen et al. 2016) were successively conducted by the Renewable Energy global innovations website as key scientific articles. Follow-up reports. It is believed that this research achievement “proved for the first time the true feasibility and practicality of microalgae for the production of high-value products while reducing industrial pollutantsâ€.
Based on the above research results, the researchers were respectively invited by Applied Energy and Applied Microbiology and Biotechnology to write an overview paper (Chen et al. 2015; Zhu et al. 2016).
The above research was funded by the "973" program, the National Natural Science Foundation of China, the Hubei Provincial Natural Science Foundation of China, the frontier projects in the field of young talents in the Knowledge Innovation Project of the Aquatic Institute, and the horizontal projects of the Sinopec companies.
Magnesium Nitrate,Magnesium Nitrate Granular,High Tower Magnesium Nitrate,Magnesium Nitrate Hexahydrate
SHANXI HUAXIN FERTILIZER CORP. , https://www.sxhuaxingroup.com