Blockage and corrosion at the cold end of air preheater is a common problem that plagues most thermal power plants. It will affect the operating cost efficiency and safety of the unit. In severe cases, it may lead to unscheduled shutdown of the unit. In particular, many units are fed with coal with high sulfur and moisture content in recent years. This problem often becomes more serious after the installation of SCR DeNOx system.
The "anti-blocking technology for air preheater" in the "a series of special technologies for energy saving, environmental protection and safety" developed by Shanghai Shenergy Power Technology Co., Ltd. (hereinafter referred to as “Shenergy Technology”) can effectively increase the average temperature at the cold end of air preheater in an energy-saving and cost-effective way (especially in winter and under low-load conditions). It can greatly alleviate the problem of blockage and corrosion at the cold end of air preheater fundamentally. This technology has been successfully applied in several power plants, including Waigaoqiao 3, and satisfactory results have been achieved. Learn more?
Various "low-temperature economizers" have been widely used in China in recent years. However, as a flue gas waste heat recovery and utilization technology, they often bring small benefits, and cause wear and leakage of heat exchanger and even unscheduled shutdown of the unit, difficulty in maintenance of heat exchanger after corrosion and blockage, etc. Many power plants have become "jittery at the mention of low-temperature economizers" nowadays.
The "efficient, reliable and environmental-friendly flue gas heat recovery technology" in the "a series of special technologies for energy saving, environmental protection and safety" developed by Shenergy Technology, including but not limited to the efficient, reliable and environmental-friendly low-temperature economizer technology, whose outstanding advantage lies in customized design, has been successfully applied in several power plants, including Waigaoqiao 3, and satisfactory results have been achieved. Learn more?
For the efficiency improvement retrofitting of sub-critical units in service, Professor Feng Weizhong, the General Manager of Shanghai Shenergy Power Technology Co., Ltd., after years of research, put forward the "high-temperature sub-critical technology" in 2010 (with the relevant domestic and international patents). The key is to keep the main and reheat steam pressures of the unit basically unchanged and greatly increase the main and reheat steam temperatures of the unit to the 600°C level of the existing ultra-supercritical units. With the customized integration and application of some "a series of special technologies for energy saving, environmental protection and safety", it can significantly improve the energy efficiency, environmental protection, and flexibility levels of the unit. The "high-temperature sub-critical technology" is not only applicable to the significant efficiency improvement retrofitting of sub-critical units in service, but also applicable to new units.
The "high-temperature sub-critical technology" has been applied to the 320 MW sub-critical unit of CR Xuzhou Power Plant, and an excellent result beyond expectation has been achieved. The performance test report shows that the coal consumption rate of this unit is less than the contract guarantee value of 287 g/kWh under rated conditions after the retrofitting. It has reached the level of ultra-supercritical units in service.
It should be noted that no matter for new units or retrofitted projects, the needs of different power plants are very different due to the different conditions of the power plants. Therefore, customization shall be a key need for both new and retrofitted thermal power generating units. At present, however, "copy-and-paste" and "mass production" modes are more common in the industry. The consequences are also obvious: Many technologies fail to achieve their design performance, and some technologies that work well in certain projects become inadaptable in other projects and even have "side effects".
The business scope of Shanghai Shenergy Power Technology Co., Ltd. covers sub-critical/supercritical/ultra-supercritical, straight condensing/cogeneration, and new/in-service units. Our outstanding advantage is to provide customized, systematic and cost-effective energy saving and emission reduction solutions according to the specific configuration and needs of the unit, thus comprehensively improving the unit's performance. So far, all the same design solutions have been different from each other to a certain extent.
In recent years, the international and domestic energy and power industries have undergone profound changes. The power grid proposes more and more urgent needs for in-depth peak load regulation and low-load or even ultra-low-load (less than 40% load) operation of thermal power generating units. However, traditional thermal power generating units usually face difficult problems, such as sharp increase in coal consumption, sharp decrease in boiler combustion/hydrodynamic stability, and failure of SCR DeNOx system at low loads. Comprehensive challenges are posed for the cost efficiency, safety, and environmental protection of the units. Because of the difficulty in low-load operation of units, the National Energy Administration has listed the "20%-100% of peak load regulation capacity for coal-fired generating units" as a development target for 2030.
For various problems of the unit under low-load conditions, Shanghai Shenergy Power Technology Co., Ltd. has developed the "a series of special technologies for energy saving, environmental protection and safety" after years of research and application. The technologies include "efficient and clean combustion technology based on generalized regeneration", "safe, environmental-friendly and stable ultra-low load technology", "energy-saving and wide-load SCR DeNOx technology", and "power and energy saving generalized variable frequency technology". These technologies can comprehensively improve the performance of the unit under (ultra) low-load conditions. After being applied to the 320 MW sub-critical unit of CR Xuzhou Power Plant, these technologies have passed the in-depth peak load regulation capacity certification at 19% loads, and the target planned by National Energy Administration was achieved 11 years in advance.
According to the investigation, for a considerable number of (ultra) supercritical units that have been put into operation, the actual operating efficiency of the steam turbine is significantly less than the design value. In addition, these units are facing problems such as frequent boiler pipe bursting due to overtemperature. This has a great impact on the safety and cost efficiency of the units. The reason behind this is the problem of oxidation and solid particle erosion that has plagued the international thermal power industry for decades. If the oxide scale peeling off from the boiler pipe accumulates in the pipe, it will cause overtemperature and even bursting of such pipe. If the oxide scale in the pipeline enters the steam turbine or the bypass valve with the steam flow, it will cause solid particle erosion (SPE) of the turbine blades and the bypass valve element, resulting in continuous decrease of efficiency of the units.
After more than ten years of research and practice on the problem of oxidation and solid particle erosion, Shanghai Shenergy Power Technology Co., Ltd. has developed the "a series of technologies for comprehensive prevention and management of oxidation and solid particle erosion". These series of technologies can systematically and comprehensively solve many problems caused by oxidation and solid particle erosion.
The popular "plasma ignition technology" and "small oil gun ignition technology" in recent years in China are aimed at saving fuel at the boiler ignition and start-up stage. However, it has generally caused dry burning of the heating surface of boiler and formation and peeling off of oxide scale at the ignition stage, because the incompletely burned long flame directly scours the convection heating surface of the boiler. It can easily cause the problems of boiler pipe bursting and steam turbine efficiency decline due to blockage by oxide scale.
The "energy-saving, safe and environmental-friendly unit startup technology" in the "a series of special technologies for energy saving, environmental protection and safety" developed by Shanghai Shenergy Power Technology Co., Ltd., breaking through from the entire thermal system, rationally utilizes the heat and working fluid in the system to greatly improve the operating conditions of the unit, especially the boiler, at the (cold) startup stage. It can effectively improve the performance indexes of energy saving, environmental protection and safety at the unit startup stage.
Compared with the straight condensing units, in addition to supplying power to the power grid, the cogeneration units also provide steam or hot water with certain parameters for enterprises or resident users. This also causes problems and demands different from those of the straight condensate units. They can be summarized as: 1) the demand for increasing, changing or expanding the heating capacity (parameters), 2) the demand for in-depth peak load regulation of cogeneration units, and 3) the demand for significant energy saving, emission reduction and service life extension of low-parameter, small-capacity cogeneration units.
It needs to be emphasized that, since the heating parameters, flow rate, and demand of cogeneration units vary greatly, the formulation of heating renovation solution shall also be based on customization. According to the investigation, however, there is currently a general lack of targeted and customized design solutions for heating and efficiency improvement needs of cogeneration units in the industry. In this regard, Shanghai Shenergy Power Technology Co., Ltd. has reserved the "retrofitting technologies for heat supply and efficiency improvement of cogeneration unit" by concentrating in research and development. Some of the technologies are being applied.