Research and development methods and entrained-flow gasification theory
Coal water slurry gasification involves complex chemical and physical processes such as high temperature, high pressure, heterogeneous phase, flow, transfer and chemical reaction, so it is difficult to study the process under industrial conditions in the laboratory. In this regard, East China University of Science and Technology, under the guidance of related theories of chemical engineering and technology, combined with years of research and development accumulated methods and experience, put forward a hierarchical mechanism model to correctly grasp the relationship between various influencing factors on the basis of profound and comprehensive analysis of gasification process. The complex gasification process is decomposed reasonably, the proposition transformation of research topic is realized, and a set of scientific research and development methods suitable for studying entrained flow gasification process is created. That is to say, the laws of fluid flow, atomization and mixing are studied on the cold mold device; Based on engineering experience, a one-step transformation method of comprehensive iteration on computer is proposed.
The internationally advanced three-dimensional laser Doppler particle dynamic analyzer (DualPDA) and Mafiven particle analyzer were used to study the velocity distribution, concentration distribution, residence time distribution, atomized particle size and its distribution of the fluid in the entrained-flow bed on a large-scale cold model device, and the mathematical models of the three-zone model of flow and reaction, velocity distribution, concentration distribution, residence time distribution, atomized particle size and its distribution were established respectively, thus forming the systematic theory and patented technology of entrained-flow coal water slurry gasification. Nozzle is the core of coal water slurry gasification technology. The performance of nozzle will directly affect the result of gasification reaction and the service life of refractory brick and nozzle itself. On the basis of years of scientific and technological research, East China University of Science and Technology cooperated with the former Lunan Fertilizer Plant and the National Engineering Research Center for Coal Water Slurry Gasification and Coal Chemical Industry to develop a new type of coal water slurry gasification nozzle, which realized technological innovation and industrial application.
The new nozzle is an internal rotating nozzle and a prefilming nozzle, in which the internal rotating nozzle has obtained the national invention patent. From 65438 to 0995, this new nozzle was tested in Texaco gasification unit of Lunan Fertilizer Plant. All technical indexes of the new nozzle are higher than that of Texaco nozzle, saving 0.2% of coal, 2-5% of oxygen and increasing the carbon conversion rate by -2 percentage points. Seven indicators set a new production record at that time. The expert appraisal conducted by the Science and Technology Department of the former Ministry of Chemical Industry has filled the gap in China and formed the technical characteristics of coal water slurry gasification in China, reaching the international leading level. This project won the first prize of Shanghai Science and Technology Progress Award 1998.
Due to the rapid erosion of coal particles in coal slurry, the material of coal slurry gasification nozzle is very easy to wear, and the service life of imported nozzle is only 3 months, which directly affects the long-term stable operation of gasification device. East China University of Science and Technology successfully completed the "Ninth Five-Year Plan" national key research project "Research and development of key components of gasifier" and developed a new type of wear-resistant coal-water slurry gasification nozzle. The industrial application of the nozzle in Yankuang Lunan Chemical Fertilizer Plant shows that its service life can reach more than half a year. In order to save foreign exchange and form coal gasification technology with independent intellectual property rights, under the auspices of the Science and Technology Department of the former Ministry of Chemical Industry, this project was approved by the former State Planning Commission 1.996 in June. As a key scientific and technological research project of "Basic Research on Development and Application of New (Multi-nozzle Opposed) Coal Water Slurry Gasifier", it was jointly undertaken by East China University of Science and Technology, the former Lunan Fertilizer Plant and the First Design Institute of the former Ministry of Chemical Industry.
The new gasifier is a four-nozzle opposed structure. By adjusting the nozzle configuration, the structure and size of the gasifier are optimized, and the heat and mass transfer process is strengthened in the form of impinging jet, which is more conducive to gasification reaction and prolonging the service life of refractory bricks. The operation results of the pilot plant show that the main technical indexes completely exceed the gasification level of Texaco coal water slurry. Compared with Texaco gasifier, it saves -7% coal and -7% oxygen, increases the effective gas composition by ~ 2 percentage points, and increases the carbon conversion rate by 2-3 percentage points. According to experts' appraisal, "this project fills the gap in China and is a milestone of coal gasification technology with independent intellectual property rights in China, which can compete with international advanced technology. Technical indicators show that the project has reached the international leading level in the field of coal water slurry gasification. " The project won the "Ninth Five-Year" National Outstanding Scientific and Technological Achievement Award organized by the Ministry of Science and Technology, the Ministry of Finance, the State Planning Commission and the State Economic and Trade Commission, which laid a solid technical foundation for the industrialization of coal water slurry gasification technology with independent intellectual property rights in China.
It can be seen that after more than ten years of production practice and research and development, China has established scientific research and application bases such as experimental research, pilot test and industrial production in coal water slurry gasification technology; It has formed a scientific and technological backbone team with R&D capability, engineering design and production practice experience, and has made gratifying technological progress and scientific and technological innovation achievements.
These achievements will provide reliable technical support for the transformation and upgrading of traditional industries and the development and application of clean energy in China, and will further promote the progress and development of related technologies in the field of clean coal technology.