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Author/Source of the award for Nanjing Tech University’s gas purification membrane production technology: Sinochem News Network; Date: 2021-02-01; Clicks: 7. Enables ultra-low emissions of pollutants and efficient recovery of dust. It not only allows the gas purification membranes to function more effectively but also keeps the surface of the membrane materials free from residues, while enabling efficient recovery and reuse of industrial dust. Recently, the project on key technologies for the design and preparation of gas purification membrane materials and their applications, carried out jointly by Professor Zhong Zhaoxiang’s team from the School of Chemical Engineering at Nanjing University of Technology, together with Jiangsu Jiulang High-Tech Co., Ltd., Nanjing Membrane Materials Industry Technology Research Institute Co., Ltd., Jiangsu Jiayi Thermal Power Co., Ltd., and other organizations, was awarded the First Prize in Science and Technology of Jiangsu Province for the year 2020. This technology overcomes the current limitations of membrane technology in the field of gas purification, such as low gas permeation rates and poor resistance to contamination, thereby enabling the large-scale use of separation membrane materials in gas purification processes. Advancing purification technologies for propellant gases: Strictly controlling the emission of ultra-fine dusts and achieving efficient and clean utilization of resources are common challenges faced by industries such as chemicals, energy, steel, metallurgy, and building materials. Common gas dust removal methods currently in use include bag filtration, cyclone separation, electrostatic dust removal, and wet capture. These methods are effective at removing dust particles of larger sizes, but have low separation efficiency for ultra-fine dust (sub-micron grade). As a new and efficient separation technology, membrane technology has been widely applied in fields such as liquid separation, but it is still in its infancy in the field of gas purification. “Industrial flue gas has a large volume of emissions per unit of time, reaching several million cubic meters per hour; the driving force for filtration is low. Moreover, the existing liquid separation membranes have a low permeability rate, making them unsuitable for gas purification processes. ”Zhong Zhaoxiang explained that the gas purification membrane they developed provides an effective solution. This technology, which enables the effective separation of particles by gas purification membranes while allowing gases to pass through quickly, is the microstructure control technique for membrane materials. This technology proposes a membrane material design method for gas-solid separation, establishes a relationship between the performance of the membrane structure and its control parameters, enables precise adjustment of membrane thickness, pore size, and porosity, and results in a gas permeation rate that is 30% higher than that of internationally advanced technical products. Innovative development of dual-repellent membrane materials. “However, there are numerous air purification systems, and in addition to common solid particles, the target contaminants may also include oily pollutants, oily aerosols, and ultra-fine particles. These substances tend to adsorb onto the surface of membrane materials, causing the filtration pressure difference to rise rapidly, which makes it difficult to meet the requirements for operational stability in industrial processes. ”Zhong Zhaoxiang said that if membrane materials can be made both hydrophobic and oleophobic, oily substances will not adhere to the surface of the membrane. This effect is similar to the \"lotus leaf effect\": when water drops onto a lotus leaf, they form beads; similarly, oil drops falling on the surface of membrane fibers with oleophobic properties also appear as droplets. Over time, these small oil droplets that accumulate on the membrane surface grow larger, until the gravity acting on the droplets becomes greater than the adhesive force between them and the membrane surface. Under the influence of gravity, the oil droplets gradually slide off the surface of the dual-oleophobic membrane, thereby enabling the membrane material to be regenerated. To this end, Zhong Zhaoxiang’s team invented a technique for modifying the surface of membrane materials to make them hydrophobic and oleophobic. By combining surface morphology control with online backwashing technology, they overcame the problem of membrane materials being easily contaminated by oily aerosols, and developed a dual-hydrophobic membrane material that is unique both domestically and internationally. “The uniformly porous superhydrophobic membrane material we developed has contact angles of over 120° with both water and oily substances. In addition to the basic separation function of membrane materials, it exhibits excellent hydrophobic and oleophobic properties; its surface does not easily absorb contaminants, and the low adhesion force facilitates the cleaning of the superhydrophobic membrane, thereby extending its reusability. Its stable operational life is more than twice that of similar membrane products available abroad. ”Zhong Zhaoxiang said so. New processes expand application areas To achieve the controlled production and industrial application of gas purification membranes, Zhong Zhaoxiang’s team has developed a series of new processes for using such membranes. The series of membrane-based flue gas treatment process equipment they have developed have been widely used in the purification of flue gases from coal-fired boilers, biomass boilers, and waste incineration units in chemical enterprises. The dust concentration in the purified gas is less than 5 mg/m3, which is below the **ultra-low emission standard of 10 mg/m3; moreover, the energy consumption is reduced by more than one-third compared to bag filter dust removal systems. To address the common issues in the recovery of high-value powder products such as catalysts, titanium dioxide, and dyes used in chemical processes, they also developed a recovery process for such high-value powder products, utilizing membrane technology to achieve efficient recovery of these powders in just one step, and this process has been put into large-scale use. A company in Hunan uses this process to recover an additional 20 tons of catalyst products each year, reducing significant amounts of wastewater and waste gas emissions. The stable operational life of the membrane process is more than 4 times longer than that of the traditional process. According to statistics, gas purification membrane technology has been adopted by more than 60 enterprises including Sinopec, Hengyi Petrochemical, and Jiangsu Huachang Chemical. In the past two years, it has generated a total output value of 2.596 billion yuan and profits of 457 million yuan; in addition, it has processed over 180 billion standard cubic meters of waste gas, resulting in the reduction of more than 2,700 tons of fine dust.