Advanced Materials Research Vols. 634-638

Abstract: Flow and mass transfer characteristics in axisymmetric sinusoidal wavy-walled tubes with different dimensions are investigated experimentally. The overall pressure drops and the mass transfer rate are measured. The results showed that the wavelength and amplitude of the wavy-walled tubes obviously affect the fluid flow and mass transfer characteristics. Especially, the mass transfer enhancement is compared with the corresponding straight-walled tube under equal pumping power condition. It is found that the greater mass transfer enhancement appears at the moderate Reynolds number, and the optimum mass transfer enhancement could be obtained in the wavy-walled tube with Fw=0.5.

Abstract: Traditional assessment techniques can't predict the explosion with effects of water spray system. A method of explosion simulation which based on FLACS software for Petrochemical plant with water spray were used for simulating the explosion risk of a coal gasification company’s plant. Simulation results indicate that the water spray system can significantly weaken the devices exploded consequences. This method can be used for fire protection system design and optimization of layout for petrochemical plants.

Abstract: Integrated multilayer wrapped vessel is a new type of multilayer high pressure vessel construction diffusely used in various process industrial productions. The prestress of the integrated multilayer wrapped vessel of inside diameter 500mm during its manufactural process was investigated. The experimental results showed that, the circumferential prestress distributions in the inner cylinder and the laminate during its manufactural process were approximately exponential function, thus in order to make the circumferential prestress contribution in the inner cylinder even as possible, the laminates should be staggered uniformly as the same circumferential angle during the manufactural process of the actual vessel, which is of an important significance to insure its manufactural quality and safe application.

Abstract: Coal is the main material for human’s production and livelihood, and human pay more attention to it. Nowadays, Chinese crushing equipment’s volume is bigger, in view of this phenomenon, the author put forward to design a pulverized coal intelligent sample preparation device. This design not only has small size, but also has coarse crushing, drying, screening, grinding, grading and pulverized coal’s intelligent detection. It can well detect pulverized coal’s composition and year. In this paper, the author research on this mechanism’s coarse crushing device. Firstly, the author analyze the composition of coal to make a better foundation for crushing, then introduce the overall process of coarse crushing, and research the various parts of working principle and related parameters.

Abstract: In view of China’s current coal crushing equipment size is too large, this paper aim to design a small coal sample preparation system. This system utilizes the principle of the cone crusher for coarse crushing, and after the pulverized coal is dried in drying apparatus, it will let the pulverized coal enters into the fine grinding device from fixed screening device. The pulverized coal pulverized by fine grinding apparatus, classification by the classification device, and enters into the infrared light detecting device from transmission apparatus to detect its composition. This device’s transmission is based on control of PLC to achieve. At first, this paper describe the operating principle of PLC, then select the hardware and software components of transfer part, and simulate the control part at last.

Abstract: Corrosion perforation of air cooler on atmospheric tower in refinery is mainly caused by the outer wall pitting, and the leading factors which results in the air cooler failure are Cl-, PH , temperature and Na+. With orthogonal model design test program to the main factors, and through polarization curves experiments obtain the corresponding corrosion potential, corrosion rate, pitting potential. Analysis the change of Cl-, PH value, Temperature and Na+ to the air condenser corrosion influence. The results show that, Cl- concentration, Na+ concentration rise make air cooler on atmospheric tower happening corrosion easily; PH value rise make air cooler on atmospheric tower happening corrsion not easily, which has a protective effect to the passive film; Temperature rise make air cooler on atmospheric tower passivation membrane formation rate increase, and at the same time pitting corrosion is more easily to happen.

Abstract: Based on characterization of various properties of coking formation during the processing of pyrolysis of coal to acetylene in the plasma, and the chemical group composition of the coal, the reaction central - border zone characteristics of plasma and the specific circumstances of the reactor, the mechanism of coking on reactor wall is put forword during pyrolysis of the coal to acetylene in the plasma, which aromatics, colloids, asphaltenes and carbenes happen condensation reaction by dehydrogenation in plasma border reaction zone. Besides, a method is proposed that double peak particle size distribution of coal particle can eliminate coking continuously, and it get experimental validation.

Abstract: The pyrolysis of coal to acetylene is studied with Pingshuo coal, Zichang coal and Dongshan coal in the plasma, and its course is analysised by coal chemical groups. The reaction mechanism of imitate free radicals is proposed in the pyrolysis of coal to acetylene in the plasma, the free radicals formation of high-temperature plasma and the composite dynamics are discussed. The results can educe that the acetylene content is higher of the organic product in the high temperature center zone of the pyrolysis of coal to acetylene in the plasma which base on the discussion of the saturates free radicals generating and compounding, combine with the reaction of aromatics, colloids and asphaltene and carbenes. It also can indicate that free radical reaction mechanism is applicable and feasible to explain coal of high-temperature centre zone in the plasma reaction.

Abstract: In order to deal with the “wall flow effect” and the “scaling effect” that commonly exist in packed tower, a new type of efficient symmetrical-flow packed equipment was developed. In the same condition, the symmetrical-flow packed equipment was studied comparatively with the common packed equipment by experimental and numerical simulation, and the results such as wall-flow contours and velocity distribution were given. The study results showed that the wall flow was significantly reduced by about 31% and the gas-liquid velocity was more uniformly distributed compared to the normal packed tower. The results showed that the symmetrical-flow packed equipment had a very good effect on improving the uniform distribution of the macroscopic flowing of fluid. The symmetrical-flow packed equipment, therefore, can effectively reduce the “wall-flow effect” and eliminated the “scaling effect”, and also increase the mass transfer efficiency of the packed tower is improved.

Abstract: The present study is concerning qualitative and quantitative detection of different coal samples based on near infrared spectroscopy. Firstly, near infrared spectroscopy combined with discriminant analysis (DA) was used for the coal cinder characteristics in different spectral pre-processing methods, at the same time it will establish the quantitative of the total moisture. The result indicated that 97.78% recognition ratio for calibration and 93.33% recognition ratio for validation were achieved by DA for the cinder characteristics. The PLS quantitative model of the total moisture of the establishment of the original spectral was the best, the correlation coefficients of calibration and prediction respectively were 0.981 and 0.641, RMSEC, RMSEP and RMSECV respectively were 0.859, 2.51 and 3.44.