Chloride ion is the key operating index in desulfurization system of power plants. Rapid and accurate monitoring of chloride ion content in desulfurization slurry is of great significance for anti-corrosion of desulfurization equipment, optimization and adjustment of operation process, as well as desulfurization waste water discharge and water saving. By studying the pretreatment method of sample, a high-efficiency composite medium filter is developed, and the method suitable for the desulfurization system sample pretreatment is studied, and the laboratory test is carried out. At the same time, by studying the principle of online measurement method of chloride ion in desulfurization system, a solid polymer membrane chloride selective electrode is developed, and on-line monitoring technology of chloride ion in desulfurization system of power plant is developed, and the accuracy test in laboratory and field industrial application test are carried out. The results show that, the technology can realize continuous and accurate online monitoring of chloride ion content in desulfurization slurry, reduce the workload of laboratory personnel greatly, and improve the accuracy of chloride ion measurement. It is of great significance to realize the economic and intelligent operation of desulfurization system equipment.

Infrared spectroscopy detection technology has been widely used in petrochemical, pharmaceutical and other industries due to its fast detection speed, no damage to the sample, no pollution, easy to operate and other characteristics. The infrared spectroscopy detection mainly includes qualitative detection and quantitative detection. The qualitative detection usually uses comparative method, which compares with standard substances or consults standard spectra. The quantitative detection calculates the corresponding components content by measuring the intensity of characteristic absorption bands and combining with chemometrics methods. This article elaborates the applications of chemometric methods (including artificial neural networks and partial least squares) in detection scenes such as acid value, moisture, antioxidants and furfural for electric power oil. Finally, some proposals of infrared spectroscopy in oil detection are put forward.

Rapidly growth of organic solid waste (OSW) has caused serious social and environmental issues. Co-combustion is an economical and environmental method to treat OSW. However, there will be a variety of heavy metals discharged with flue gas during combustion as OSW contains them. Therefore, this study conducted an experiment on the migration of heavy metals and generation of micro particles during the co-combustion of OSW and lignite. The results show that, the release of heavy metals during combustion not only depends on the concentration of heavy metal the fuel contains, but also on the chemical mechanism at high temperature. The content of Pb, Cd and As in the flue gas of blending fuel is obviously lower than that of sole OSW, but Cu, Zn, Co and Mn shows opposite tendency. In addition, the particle size distribution of the four fuels all shows a normal distribution at 800 ℃ and 850 ℃, but large particle size generates when the combustion temperature rises to 900 ℃.

At present, China’s thermal power plant steam/water pipeline design standard stipulates that the load variation coefficient of spring hangers should not exceed 25%. Accordingly, the designed proportion of the constant support hanger is too high, and the “illegal” transfer of the load will cause the pipe operation deviates from the design line, and the stress increases. This paper analyzes the relationship between the constant degree and the load variability factor of constant hanger. The optimization design case shows that, properly increasing the load variation coefficient of spring hangers in the design of steam/water pipelines can increase the proportion of spring hanger configuration and reduce the occurrence of abnormal pipeline expansion.

China has abundant high-alkali coal resources. This article provides a comprehensive review and summary of the research and engineering application progress of high-alkali coal combustion technology from the aspects of basic research, key technologies, and engineering practice. In particular, the latest status of the mechanism research and practice of fully burning Xinjiang high-alkali coal in a wet-bottom boiler is introduced. The review aims at providing a reference to develop more economic combustion technology that can safely co-fire a high proportion or even solely burn Xinjiang high-alkali coals in a long operational period.

Although the reserves of high-alkali coal represented by Zhundong coal is huge, the problem of coking on heating surface of the boiler is prominent during co-firing high-alkali coals in thermal power units, which not only reduces the boiler thermal efficiency, but also seriously threatens the safe, stable and economic operation of the unit. In order to solve this problem and promote the utilization of high-alkali coal, this paper reviews the researches on coking of the heating surface of high-alkali coal boilers and the prevention. Up to now, extensive researches have been carried out at home and abroad on the characteristics of coking on the heating surface of coal-fired boilers, coking mechanism, influencing factors, prevention and control measures, and so on, and fruitful research results have been achieved. On the basis of controlling the quality of coal, improving boiler structure, and optimizing boiler operation, the preparation of coating on the heating surface of boilers has also become an important technical path for preventing and controlling coking. In the future, the coating should possess excellent comprehensive properties such as high temperature resistance, corrosion resistance, wear resistance, thermal conductivity, thermal fatigue and so on, while having outstanding coking resistance. Meanwhile, the coating also should have desirable preparation economy and preparation efficiency, especially the on-site applicability.

High-alkali coal such as Zhundong coal has huge reserves in Xinjiang, in which rich alkali metal elements can easily lead to fouling and slagging problem on heating surface of the furnace, thus to decrease the safety of boiler. It is of great significance to develop efficient and clean combustion power generation technology for high-alkali coal to achieve the “double-carbon” goal. The research progress of the online monitoring technology in high-alkali coal combustion furnace based on spontaneous emission radiation analysis is summarized. The development trend and dynamics are discussed focusing on the research status and application of emission spectrum technology and spontaneous emission radiation imaging and image processing technology in high-alkali coal combustion monitoring. Emission spectroscopy can obtain the temperature and component concentration by processing the spectral radiation signal emitted by the flame at different wavelengths. Recently, it has been widely used to measure the combustion temperature and the gaseous alkali metal concentration in the industrial furnace and judge the slagging trend in the furnace qualitatively. Different from emission spectroscopy technology, spontaneous emission radiation imaging and image processing technology has the ability to analyze the spatial distribution of signals. The technology obtains the spontaneous radiation image in the furnace via CCD, CMOS and other surface array sensors. Based on image processing technology and thermal radiation imaging theory, the temperature distribution of the combustion field in three-dimensional space can be obtained combining with solving radiation inverse problem, which makes it possible to monitor the three-dimensional visual of slagging formation. In the future, monitoring of the fouling and slagging on the heating surface in two or three dimensions should be carried out based on emission spectroscopy technology, spontaneous emission radiation imaging and image processing technology. Combined with the distribution of parameters such as combustion temperature and gaseous alkali metal concentration in the furnace, a quantitative judgmental index of fouling and slagging on the heating surface of high-alkali coal combustion should be established to achieve the goal of online prediction of fouling and slagging on the heating surface.

Further research on slag-tap boiler can promote the application of fully burning high-alkali coal technology. In this study, a supercritical 350 MW once-through double-U flame slag-tap boiler is taken as the research object and the combustion chamber, slag collection tube bundle and cooling chamber are taken as the calculation units, the thermal calculation is performed from the perspective of heat balance. The flow field, temperature field and component field in the boiler under design condition and at variable loads are studied. The deviations of several flue gas temperature results obtained by thermal calculation and numerical simulation are within 40 K. At the outlet of the combustion chamber, the deviation is only 1.2 K. The temperature deviation of flue gas at the outlet of cooling chamber is 15.6 K. After verification and comparison, it is concluded that the thermal calculation method adopted can be applied to the thermal calculation on double-U flame slag-tap boiler that fully burning high-alkali coal. The flow field is well organized. The recirculation zones formed by swirling flow can increase the movement path of pulverized coal particles in the combustion chamber and promote the burning. When the flue gas flows through the slag collection tube bundle, the temperature greatly reduces. The flow field is also disturbed, which can effectively capture the ash. At variable loads, the velocity field in the boiler decreases proportionally according to the reduction ratio of the amount of coal. However, the size of the recirculation zones is basically unchanged. The temperature level in the boiler reduces, when the amount of coal reduces from 100% to 75%, the flue gas temperature at the outlet of the combustion chamber reduces by about 75 K, and the flue gas temperature at the outlet of the cooling chamber reduces by about 200 K. This study can provide reference for fully burning high-alkali coal in double-U flame slag-tap boiler.

In order to compare the particle formation characteristics of typical high-alkali and high-chlorine Xinjiang coal under combustion conditions, a three-stage high temperature drop tube furnace was used to carry out the combustion experiment of Zhundong coal (ZD) and Shaerhu coal (SEH) in air atmosphere. The characteristics of particulate matter after combustion were analyzed. Particulate matters were collected by Dekati low pressure impactor+ (DLPI+) and the mass-based particle size distribution, elemental compositions and morphology were discussed. The results showed that the particulate matter produced by the combustion of the two coal samples presents a double-peaked model. The fine particle yield of SEH is significantly higher than that of ZD. The main components of sub-micron particles were Na and Cl. The Cl in PM₁₀ accounts for 11.8% and 28.9% of the Cl content in ZD and SEH raw coal, and Na accounts for 2.66% and 7.53% of the Na content in ZD and SEH coal ash. High levels of alkali metals and Cl promoted the formation of fine particles. A large amount of Cl in SEH raw coal migrated into particles and contributed greatly to the formation of sub-micron particles.

As a kind of slag-tap boiler, cyclone-fired boilers exhibit significantly different aerodynamics comparing with pulverized coal (PC) boilers. However, by far there are still lack of CFD models that are able to provide effective guidance to the design and operation of cyclone-fired boilers. A CFD model of cyclone-fired boilers was developed in which the capture of coal particles by the molten slag layer was considered through a slag layer coal particle capture model. This model was then employed to investigate the aerodynamics and flue gas recirculation (FGR) optimization design of a 550 MW cyclone-fired boiler. The results demonstrate the highly nonuniform characteristics of furnace aerodynamics of cyclone-fired boilers due to the strong swirling flows created by the cyclones leads to the formation of localized high temperature zones and severe boiler fouling problems at the entrance of boiler convection pass. Thus, it is critical to adapt the FGR design with the nonuniform furnace flow and temperature distributions. The simulation results show that, with the optimized FGR design, the high temperature zones and the resulting severe fouling problems were effectively mitigated.