Instructions for nitrogen closed-loop cycle drying of materials containing solutes

Thread Content

I. Project Overview: In industries such as chemicals, pharmaceuticals, and synthesis, the material drying process is often characterized by long drying times, slow rates, and low efficiency. Moreover, large amounts of exhaust gas containing organic solvents are released, a problem that is particularly evident during the air-drying of heat-sensitive materials. This poses significant challenges for companies in terms of environmental management, and it represents a major obstacle in both production and environmental protection efforts for most enterprises. During the closed-loop drying process, the volatiles that evaporate need to be removed continuously and efficiently. The solvent-free dry nitrogen is returned to the dryer for reuse, thus achieving a closed-loop system. If the solvent cannot be removed efficiently, it will affect the secondary drying effect of the recycled nitrogen, resulting in an extended drying time for the material; in severe cases, excessive residual solvent levels can lead to drying failure. This is particularly evident during the low-temperature air flow drying of heat-sensitive materials, and it represents the main bottleneck in drying production. The nitrogen closed-loop circulation drying system developed by Shijiazhuang Liuke Environmental Protection Machinery Co., Ltd. recovers the solvents from the gases emitted by the dryer, allowing clean nitrogen to be returned to the dryer for reuse. This enables the recycling of nitrogen, results in zero emissions of waste gas, significantly increases the drying speed and improves the quality of drying – making it an ideal solution for saving energy and improving efficiency. II. Application Cases: At present, our company has deployed multiple sets of equipment for use in drying processes, and these devices are performing well, delivering significant economic and environmental benefits. Taking the application in a certain enterprise as an example, the following explanations are provided: (1) Drying conditions for the pesticide active ingredient – The output per batch is 3600 kg; the wet material contains 20–25% volatiles (petroleum ether), while the dried product contains no more than 0.1% volatiles (petroleum ether). The particle size ranges from 80 to 200 mesh, and the material’s temperature tolerance is no higher than 50°C. (2) Operation of the drying device before modification: A three-in-one vacuum evacuation drying method was used, with a drying time of 16–20 hours; the drying efficiency was very low, which restricted production. Meanwhile, the petroleum ether vapor extracted by the vacuum pump was discharged into the exhaust system, resulting in serious waste and pollution. (3) Usage of the modified closed-loop system: The three-in-one process was changed from vacuum reduced-pressure drying to nitrogen gas flow drying, reducing the drying time to 4–6 hours. The dried products contain less than 0.02% volatiles (petroleum ether). The entire process is safe and convenient; yield and quality have improved significantly, while labor intensity has been **reduced**. Furthermore, material balance calculations show that the solvent recovery rate reaches 99.8%, resulting in a significant reduction in the cost of product production. III. Technical Features: (1) The temperature of the drying medium does not need to be very high; however, due to its low moisture content (0.01%), it has a strong capacity to absorb moisture, enabling rapid and thorough drying of the material. The final moisture content of the product can reach 0.02%–0.1%. (2) The product is dried under oxygen-free conditions, eliminating the risks of oxidation, denaturation, and degradation of the material, as well as dangers such as explosion and combustion. (3) Solvents and nitrogen can be fully recovered, significantly reducing the cost of product consumption; the payback period for equipment investment is short (about half a year). (4) The circulation rate can be significantly increased on the basis of the existing drying process, thereby accelerating the drying speed and doubling the drying output. (5) Closed-loop drying eliminates the emission of waste gases and dust into the atmosphere, significantly reducing environmental pollution. (6) It can be paired with various types of dryers such as three-in-one, rake, boiling, and flash dryers, to meet the drying requirements of different operating conditions. IV. Application Areas: (1) Drying of materials containing solvents; (2) Drying of heat-sensitive and low-melting-point materials; (3) Large-scale drying with high air flow rates; (4) Drying of materials requiring zero exhaust emissions; (5) Improving the drying capacity and precision of existing systems. V. Company Introduction: Shijiazhuang Liuke Environmental Protection Machinery Co., Ltd. was established in 2011. It is a high-tech enterprise that focuses on technology and adheres to the principle of \"using technology to address pollution issues, with technology taking the lead\". The company possesses a strong sense of social responsibility and mission; in an era of rapid development and change in the field of environmental protection, it strives to contribute to the upgrading of China’s waste gas treatment and environmental protection industry. After more than a decade of development, the company has achieved a high level of product technology and equipment capability within the industry, and it possesses complete independent intellectual property rights. The company continues to optimize its product manufacturing processes and improve its quality management system. Its products have obtained various certifications, including ISO9001 for quality management systems, ISO14001 for environmental management systems, and OHSAS18001 for occupational health and safety management systems. The company’s subsidiary, Dezhou Lukewei Environmental Protection Technology Co., Ltd., was established in April 2021. It serves as a manufacturing branch created to address the increasing demand for equipment, as well as the adverse effects of factors such as pandemic restrictions, environmental regulations that forced production cuts, and power outages or shortages over the past few years. The Texas factory is equipped with a modern production facility covering 8,500 square meters. It has established comprehensive process control and management systems for all aspects, from raw material procurement and manufacturing to machine testing and final product inspection, which effectively addresses capacity constraints and other limitations, ensuring that projects are completed on schedule. Liuke People adhere to the spirit that \"hard work is rewarded by heaven, and giving up means gaining,\" and continue to increase investment in innovation and research and development. The company’s specialized R&D institution, Liuke Environmental Protection Technology (Shijiazhuang) Co., Ltd., has a professional and independent team dedicated to scientific research and development. As the main entity responsible for core technology research and development, it has achieved significant scientific and technical results in the development of new high-efficiency adsorbents, ultra-low emission systems for exhaust gas adsorption and purification, as well as nitrogen closed-loop circulation systems for material drying. To date, more than 10 utility model patents and 2 invention patents have been obtained. It has successively been awarded titles such as “Science and Technology-based Small and Medium-sized Enterprise in Hebei Province” and “High-tech Enterprise”. Our goal is to become part of China’s innovation team, using products with independent intellectual property rights to solve the challenges in the field of exhaust gas treatment. Shijiazhuang Liuke Environmental Protection Machinery Co., Ltd. Address: No. 186, Zhiwuyuan Street, Daguo Village, Xinhua District, Shijiazhuang City. Contact person: Li Zishuo, phone number: 18132166840. Phone: 0311-67364616. Email: 2281726989@qq.com