Characteristics of Central Heating Cinder and Its Influence on Soil Properties

[Objective]The research was designed to explore the effect of long-term stacking of solid waste produced in the coal-burning process of central heating enterprises on physical and chemical properties of soil.[Method]This study took the heating enterprises in Shenyang City as the research object.The morphological structure and element composition of coal cinder were determined by continuously collecting coal and cinder samples in different periods.At the same time,the original soil and cinder soil of the stacking site were collected to determine the changes of soil morphological structure,element composition and physical and chemical properties,so as to provide reference for the resource utilization of local cinder waste and the potential pollution risk of the stacking site.[Result]The contents of C,H,O,N,and S non-metallic elements in coal cinder decreased by 69.5%,71.2%,76.0%,74.5%,and 34.6%,respectively when compared with raw coal;while the content of Si increased significantly by 95.7%.The contents of Al,K,and Fe in cinder decreased by 4.3%,60.2%,and 33.3%,respectively,while the contents of Mg and Na increased by 36.1%and 130.9%,respectively.Compared with the original soil,the contents of C,H,and O in shallow cinder soil and deep cinder soil increased by 126.5%,67.9%,80.93%,and 21.3%,25.0%and 42.3%,respectively.The residual carbon existed in the form of activated carbon.The contents of Mg,Al,K,Na,Ca,and Fe in shallow cinder soil and deep cinder soil increased by 61.6%,5.4%,46.1%,35.8%,32.5%,6.3%and 22.3%,12.3%,12.2%,15.6%,5.8%and 2.8%,respectively compared with the original soil.The content of heavy metal elements in coal cinder did not reach the detection limit.Under the scanning electron microscope,the raw coal is mainly block structure,while the cinder is honeycombed and porous and dust.[Conclusion]Cinder stacking can significantly improve the content of organic matter and available K in shallow cinder soil,and improve the porosity and permeability of soil.In addition,cinder waste has high pH and pore structure,which can be used as acid soil conditioner,seedling flower matrix and compound fertilizer filler to take full advantage of cinder waste,improve soil structure and supply nutrients.

Dynamic disturbance rejection controllers for neutral time delay systems with application to a central heating system

In the present paper the problem of disturbance rejection of single input-single output neutral time delay systems with multiple measurable disturbances is solved via dynamic controllers. In particular, the general form of the controller matrices is presented, while the necessary and sufficient conditions for the controller to be realizable are offered. The proposed technique is applied to a test case neutral time delay central heating system. In particular, the nonlinear model of the plant and its linearized approximation are presented. Based on the linearized model, a two-stage controller is designed in order to regulate the room temperature and the boiler effluent temperature. The performance of the closed loop system is investigated through computational experiments.

Observation of Central Toroidal Rotation Induced by ICRF on EAST

Core plasma rotation of both L-mode and H-mode discharges with ion cyclotron range of frequency（ICRF） minority heating（MH） scheme was measured with a tangential X-ray imaging crystal spectrometer on EAST（Experimental Advanced Superconducting Tokamak）.Cocurrent central impurity toroidal rotation change was observed in ICRF-heated L-and H-mode plasmas.Rotation increment as high as 30 km/s was generated at ~1.7 MW ICRF power.Scaling results showed similar trend as the Rice scaling but with significant scattering,especially in L-mode plasmas.We varied the plasma current,toroidal field and magnetic configuration individually to study their effect on L-mode plasma rotation,while keeping the other major plasma parameters and heating unchanged during the scanning.It was found that larger plasma current could induce plasma rotation more efficiently.A scan of the toroidal magnetic field indicated that the largest rotation was obtained for on-axis ICRF heating.A comparison between lower-single-null（LSN）and double-null（DN） configurations showed that LSN discharges rendered a larger rotation change for the same power input and plasma parameters.

Compensating active power imbalances in power system with large-scale wind power penetration

Large-scale wind power penetration can affect the supply continuity in the power system.This is a matter of high priority to investigate,as more regulating reserves and specified control strategies for generation control are required in the future power system with even more high wind power penetration.This paper evaluates the impact of large-scale wind power integration on future power systems.An active power balance control methodology is used for compensating the power imbalances between the demand and the generation in real time,caused by wind power forecast errors.The methodology for the balance power control of future power systems with large-scale wind power integration is described and exemplified considering the generation and power exchange capacities in2020 for Danish power system.