Focusing on the problems of opaqueness and high energy consumption in coal-fired power plant wastewater recycling processes, this paper studies the simulation and operational optimization of coal-fired power plant wastewater treatment by taking a coal-fired power plant system in Inner Mongolia as an example. Firstly, based on the solution–diffusion theory, pressure drop, and osmotic concentration polarization, a mechanistic model equation for coal-fired power plant wastewater treatment is developed. Secondly, the equation fitness and equation parameters are calibrated to obtain an accurate model. Thirdly, the system is simulated and analyzed so as to obtain the influence and change trajectories of different feed flowrates, temperatures, pressures, and concentrations on various aspects of the system’s performance, such as water recovery rate, salt rejection rate, and so on. Finally, in order to reduce the operating cost of the system, an optimization analysis is carried out, with the lowest specific energy consumption and average daily operating cost as optimization goals, and the performance changes of the system before and after optimization under three different working conditions are compared. The results show that adopting the given optimal strategy can significantly reduce the system’s operational cost. This research is helpful for the digitization and low-carbon operation of coal-fired power plant wastewater treatment systems.
In order to improve production quality and efficiency of cigarette trademark, new type reel cigarette trademark on soft package adopts production mode of reel to reel, which becomes the development trend. This technique makes higher requirements on double-position connection lettering and detection technology of holographic / concave and protruding lettering. This experiment uses on-line quality examination system to conduct the relevant examinations on double-position lettering of holographic / protruding lettering of cigarette packet and makes the analysis. The experiment shows that: holographic lettering quality varies with the amount of lettering and lettering speed. For protruding lettering unit, electrified aluminium in vertical direction has a better result than that in horizontal direction. This study lays a foundation for normal production of machine and further quality inspection after lettering.
As the leading thermal desalination method, multistage flash (MSF) desalination plays an important role in obtaining freshwater. Its dynamic modeling and dynamic performance prediction are quite important for the optimal control, real-time optimal operation, maintenance, and fault diagnosis of MSF plants. In this study, a detailed mathematical model of the MSF system, based on the first principle and its treatment strategy, was established to obtain transient performance change quickly. Firstly, the whole MSF system was divided into four parts, which are brine heat exchanger, flashing stage room, mixed and split modulate, and physical parameter modulate. Secondly, based on mass, energy, and momentum conservation laws, the dynamic correlation equations were formulated and then put together for a simultaneous solution. Next, with the established model, the performance of a brine-recirculation (BR)-MSF plant with 16-stage flash chambers was simulated and compared for validation. Finally, with the validated model and the simultaneous solution method, dynamic simulation and analysis were carried out to respond to the dynamic change of feed seawater temperature, feed seawater concentration, recycle stream mass flow rate, and steam temperature. The dynamic response curves of TBT (top brine temperature), BBT (bottom brine temperature), the temperature of flashing brine at previous stages, and distillate mass flow rate at previous stages were obtained, which specifically reflect the dynamic characteristics of the system. The presented dynamic model and its treatment can provide better analysis for the real-time optimal operation and control of the MSF system to achieve lower operational cost and more stable freshwater quality.
Based on the mathematical modeling and operational optimization studies of reverse osmosis (RO) and multistage flash (MSF) desalination, the structural optimization of the hybrid process was specially studied in this work with the consideration of reducing comprehensive expenses under given operational conditions. Firstly, according to the process mechanism and flowchart of the RO and MSF seawater desalination technologies, seven hybrid structures with different feed conditions were designed, and their connection equations were established for numerical calculation. Then, in order to evaluate the economic performance of the hybrid systems with different structures, the hourly average operational cost equations of RO and MSF processes were established and formulated as the comprehensive evaluation indicators. Next, with a given water production requirement, simulation calculations of the hybrid system with seven different structures were performed. The results show that the hybrid system with the fourth structure has the lowest operational cost of 4.6834 CNY/m3, and at the same time it has the lowest blowdown. However, if we take GOR or production water temperature as the target, the optimal structure of the hybrid system is the fifth or the seventh option. The obtained results are helpful in structural optimization of the hybrid system with aspects of operational cost reduction, maximum GOR, or minimizing the wastewater discharge.
Structure and nuclear power equipment coupled system in nuclear power plant has complex dynamic interaction under seismic action. In order to study the seismic response of coupled system and assess seismic capacity of nuclear power equipment, shaking table test on coupled system by multi-dimensional seismic action was carried out. The natural frequency and damping ratio of the structure and nuclear power equipment were measured by two dynamic characteristic tests before and after the test. Furthermore, the test also included five operating basis earthquakes and one safe shutdown earthquake by using the artificial seismic waves as seismic inputs. The test results show that the dynamic amplification effect of the coupled system is obvious, and acceleration amplification factor of the equipment in the coupled system is about two times of the equipment directly connected to the shaking table in the X direction, between one and two times in the Y and Z direction. Compared with the structure, the dynamic response of the equipment in the coupled system also has a certain degree of amplification effect. In addition, the dynamic characteristics of structure and equipment change little. The equipment works well under all the test conditions, meeting the seismic requirements.
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