This study clarifies the heat transfer characteristics of flow boiling in a narrow vertical rectangular channel at each stage and optimizes the performance of a heat exchanger. The flow pattern and local heat transfer characteristics in a narrow vertical rectangular channel of steam heating with dimensions of 1400 x 250 x 2.75 mm (l x w x s) were experimentally investigated using deionized water as the working medium. Based on the visualization data, the mechanical model and empirical formulas in previous literature, a preliminary derivation of the flow pattern transition criterion for steam heating in a vertical rectangular narrow channel was obtained. The effects of the inlet temperature, mass flux, and heating power on the local heat transfer characteristics were analyzed in conjunction with the flow patterns. Based on the parametric analysis of the experimental data, a new flow boiling heat transfer correlation formula was obtained and applied to the experimental conditions. The results showed that an increase in the inlet temperature had a positive effect on the nucleate boiling section, whereas the effect on the local heat transfer coefficient was minimal after entering the churn flow phases. The increase in mass flux decreased the local heat transfer coefficient in the nuclear state boiling stage and enhanced the local heat transfer coefficient in the evaporation zone of the liquid film flow. The peak of the local heat transfer coefficient tended to shift to the left as the heating power increased. The proposed heat transfer correlation equation could well predict the local heat transfer coefficient of flow boiling in a vertical rectangular narrow channel heated by steam under these experimental conditions.
With its large scale and high flexibility, liquefied air energy storage is very suitable for integrated operation with existing power generation systems to improve the regulation ability of the grid. A novel liquified air energy storage system coupled with coal-fired power unit for heat exchange through the water/steam and the compression/expansion air is proposed. The thermodynamic model of a novel liquified air energy storage system is established with a 307 MW coal-fired power unit as the coupling object. And the parameters design and performance analysis of the coupling system are carried out. The results show that the efficiency of the system can reach 51.64 %. At this time, the corresponding energy storage/release pressure is 18/7.2 MPa. The highest return on investment of the system can reach 19.59 %, and the shortest dynamic payback period can reach 4.73 years. The sensitivity analysis shows that decreasing the heat transfer end difference of the regenerator and increasing the adiabatic efficiency of the compressor are conducive to reducing the exergosy destruction of equipment and improving the efficiency of the system. It is beneficial to improve the economic performance of the system to increase the difference between peak and valley electricity prices and the amount of peak regulation subsidy.
THE PURPOSE. Determination of effective methods of carbon dioxide capture and utilization, search for promising solutions and testing of carbon dioxide capture methods at a laboratory facility. The most popular absorption methods of CO2 capture, in which the gas reacts with a liquid absorbent.METHODS. The laboratory setup includes the CO2 source itself (gas cylinder), an absorber, and a flask with sodium hydroxide solution to analyze absorption efficiency. Efficiency is evaluated by the titrimetric method, where a solution of hydrochloric acid is used as a titrant, phenolphthalein and methyl orange act as indicators.RESULTS. For the analysis, available absorbents were selected, which are available at most thermal power plants. As a result of a laboratory experiment, it was found that a quicklime suspension of 6% has the highest sorption capacity.CONCLUSION. The decarbonization of the industrial energy sector is a complex process that requires global changes in fuel policy, namely the transition to carbon-free energy resources. An alternative energy resource is hydrogen energy, but even here carbon dioxide emissions are present. Capture and disposal will help decarbonize the main sources of pollution. Industrial carbon dioxide capture has great potential, which lies in the variety of uses of sorption materials.
PURPOSE. Development of technological solutions to reduce the amount of wastewater and reuse them in the cycle of the modernized water treatment plant at the Sterlitamak thermal power plant.METHODS. To achieve this goal, the methods of system analysis of the chemicaltechnological system were used, the sources and transformation of pollutants were determined.RESULTS. To date, Russia has experience in the disposal of wastewater from water treatment plants of energy enterprises. Basically, this method is based on neutralization with the use of various additional chemical reagents. As a result of the analysis, variants of technological schemes of a modernized water treatment plant were presented, where the concentrate after the reverse osmosis installation undergoes additional purification with the use of H- and Nacationite filters with joint or local use. The variant of the technological scheme will directly depend on the qualitative and quantitative composition of wastewater. A gypsum reactor is provided for the disposal of acidic waste regeneration solution, where gypsum is obtained as a product. These technological schemes make it possible to purify the wastewater of the installation and reuse it. These schemes are low-cost and are promising directions for the development of stations. conclusion. The developed technological solutions do not require the purchase of expensive chemicals and equipment, but only require the re-binding of equipment and the presence of a contact tank. These technologies are resource-saving, as a result, the consumption of raw water is reduced due to the reuse of waste, i.e. the cycle is low-flow. In recent decades, many industries have switched to a low-waste policy, since wastewater carries a large amount of valuable substances that can be recycled and reused.
THE PURPOSE. The work is devoted to the study and analysis of the accident on August 22, 2016 at the Reftinskaya GRES, which resulted in the operation of technological protection and, as a result, cascade shutdowns with a violation of the integrity of the UES of Russia. It should be noted that Reftinskaya GRES is one of the largest thermal power plants in Russia, with an installed capacity of 3800 MW. METHODS. Within the framework of the task set, the authors carried out a number of studies aimed at identifying cause-and-effect relationships on the basis of accident investigation acts. RESULTS. The grounds for the occurrence and development of the accident are investigated and the main causes of the accident are identified. CONCLUSION. A unified cause-and-effect diagram of the occurrence and development of an accident was compiled, indicating the events, the time of their occurrence and the links between them.
