Advanced Materials Research Vols. 550-553

Abstract: For the low pressure (LP) cylinder of a steam turbine, computation of the exhaust enthalpy is an important part in thermal power generating unit performance monitoring. A new online model for calculating the exhaust enthalpy was proposed aiming at the limitation of existing online calculation model for calculating the enthalpy of steam turbine LP cylinder exhaust steam. This model treats LP cylinder, condenser and corresponding heater as an open system, according to the energy balance equation of this open system, figuring out its exhaust enthalpy. Calculation results of typical steam turbine show that: in a large load change range, the results are close to thermal experimental value, the accuracy is similar to energy balance method.

Abstract: An introduction is made of the total procedures in designing full-condenser to the rectification device for producing PVC, which mainly involves material balance calculation, heat balance calculation and the equipment choice. Practice shows the VC amount being contained in the afterbay gases measures up to the standard requested by this technique, and is in line with discharging standard

Abstract: Experimental studies of boiling heat transfer of R134a on single horizontal smooth tube and three enhanced tubes (E27, E28, E29) have been conducted at saturationtemperature of 5°C and at a given water flow rate of 2.5 m/s. The results ind icate that the boiling heat transfer outside a single horizontal tube to the parameters of tube is selective. Tube E28 with 1811fpm (46fpi) is optimal. Experimental results showed that the test tubes could effectively enhance heat transfer. The boiling heat transfer coefficients of tube E27, tube E28, tube E29 are with the average values of 8.41, 9.16 and 6.63 times as that of smooth tube, respectively.

Abstract: The vibration of oil well sucker rod is one of the main reasons that cause breaking and disengaging to the pumping well. According to vibration mechanics theory and nonlinear theory, building the vibration mechanics model of the subsurface rod system, combined with finite element theory, using spatial beam element to establish the finite element of the rod. And according to the interface ingenerating conditions, adopt augmented Lagrange multiplier method to embed it into the finite element equations, tracing the contact friction state of the rod and tubing, to obtain the rod vibration characteristics and the contact state with the tubing during work process, to analyze the change law and influencing factors, providing the theoretical support to the vibration control of the rod.

Abstract: Anaerobic fermentative technology is an important route to solving environmental pollution and resources problems. Combined hydrogen and methane production in a two-stage process is a concept which has been developed in recent years Anaerobic biological treatment organic wastewater can produce large amounts of hydrogen and methane，which can be used as energy carrier. At present，the research focusing on the adjustment of fermentation hydrogen-methane production has been conducted. Furthermore, the simultaneous hydrogen-methane production was tested and optimized. However, it lacked combined hydrogen-methane production in an anaerobic reactor in literature so far. Based on preview experiment, the paper studied the simultaneous hydrogen-methane fermentation in an anaerobic baffled reactor (ABR) system. ABR has the advantage of biomass phase separation and integration of acidogenic and methanogenic processes to simultaneously conduct hydrogen-methane production during wastewater treatment. Through deep biohydrogen production, it can enhance the activity of hydrogen-producing acetogens (HPA) and the efficiencies of the combined hydrogen-methane fermentation system. It showed to enhance the activity of HPA was the key to the combined hydrogen-methane production.

Abstract: The wet FGD system with the characteristics of stable and mature, which had been widely used in the large thermal power plants. In this system, spray nozzle plays a key role, and the atomization performance of the spray nozzle affects the desulfurization reaction rate and efficiency directly. A new type spray nozzle, liquid beset gas nozzle was came up with in this article. It makes use of compressed gas in the internal pipeline to crush the liquid flowed out of the external pipeline into small particles. To optimize the nozzle's structure and develop its atomization performance, then considered outlet diameters of nozzle as one of the main influencing factors, sets three outlet diameters of nozzles: 4mm, 5mm and 6mm. This experiment with water for medium uses a laser particle size analyzer and a high speed camera for analysis to take atomization performance's tests of liquid beset gas nozzles under different outlet diameters and working conditions. The results of experimental studies were concluded. Firstly, when the outlet diameter is 5mm, the total spraying performance was the best. Because this outlet diameter can make the nozzle be in a balance between effective crush, fully mixing and jams preventing. Secondly, the new type nozzle had certain adaptability, when working pressures changed, and can be widely used in the wet FGD system.

Abstract: Gas turbine is the important energy recovery device in the crude oil catalytic cracking process, the operation of the gas turbine, not only related to the energy consumption level of the device, the energy consumption size of the electric power resource, but also related to the safe operation of the whole set, it can guarantee the steady producing of whole catalytic cracking unit. By using isokinetic sampling method, this study evaluates the separation properties of the third stage cyclone separator and found that the high concentrion and particles which is larger than 10 micrometre cause the failure of gas turbine.

Abstract: The gas flow field in the swirl tube was studied by experimental measurement and numerical simulation. The results show that the simulation results based on the Reynolds stress turbulent model is in good agreement with the measured results probed by the five orifice Pitot-tube. Meantime, it is analyzed that there is short cut stream at the end of the exit tube, and at the dust discharge jaws, the particles are prone to be re-entrained from the hopper. All results above provide a base for further research on the optimization of the structure and the improvement of the separation performance of the swirl tube.

Abstract: Using a two-dimensional Discrete Element Method (DEM) computer simulation, dense granular flows with the particle size range of 2-3 mm were studied between two vertical waved plates. The hydrodynamic characteristics, such as flow pattern, distribution of stress, velocity and trajectory of particles were analyzed in the process of granular flow. The results were compared to those of the flows between two vertical flat plates. The results indicated that the transient stress between waved plates was heterogeneous; the zigzag-like pressure profiles on the waved pate increased. Conclusions could be drawn that the formation of dense particle clusters disturbed spatial homogeneity and resulted in collisional anisotropy which was propitious to enhance the process of momentum, heat and mass transmission.

Abstract: Liquid leaking accidents of petrochemical equipment were always happened in weld joint of the pipeline. In order to deal with the accidents, the hot-plugging technique was adopted. And the clamp design which was the difficult point of this technology must be valued. In this paper, the hot-plugging technique and the structure of the clamp were introduced. And the calculation formula of the clamp thickness was deduced based on the influence of the injecting hole on the clamp and GB150-98. And the results would be the fundament of further study of the hot-plugging clamp design