Numerical Simulation of Combustion in 660MW Tangentially Fired Pulverized Coal Boiler on Ultra-Low Load Operation

In this paper,the combustion conditions in the boiler furnace of a 660 MWtangential fired pulverized coal boiler are numerically simulated at 15%and 20%rated loads,to study the flexibility of coal-fired power units on ultra-low load operation.The numerical results show that the boiler can operate safely at 15%and 20%ultra-low loads,and the combustion condition in the furnace is better at 20%load,and the tangent circles formed by each characteristic section in the furnace are better,and when the boiler load is decreased to 15%,the tangent circles in the furnace begin to deteriorate.The average flue gas temperature of different areas of the furnace shows that when the boiler furnace operates under ultra-low load conditions,the average smoke temperature of the cold ash hopper at 20%load is basically the same as the average smoke temperature at 15%load;in the burner area,the average smoke temperature of the cold ash hopper at 20%load is about 50 K higher than that at 15%load;in the burned out area,the average smoke temperature of the cold ash hopper at 20%load is slightly higher than that at 15%load.The average temperature of flue gas in the furnace showed a tendency to increase rapidly with the height of the furnace,then slow down and fluctuate the temperature in the burner area,and finally increase slightly in the burnout area due to the further combustion of combustible components to release heat,and then began to decrease.

Performance evaluation for sustainability of wind energy project using improved multi-criteria decision-making method

Wind power can be an efficient way to alleviate energy shortage and environmental pollution,and to realize sustainable development in terms of energy generation.The sustainability assessment of a wind project among its alternatives is a complex task that cannot be solely simplified to environmental or economic feasibility.It requires the consideration of its technological and social aspects as well as other circumstances.This paper proposes a new method for selecting the most sustainable wind projects.The method is based on multi-criteria decision-making techniques.The analytic hierarchy process and entropy weight method are combined to determine the weights of evaluation indexes,and an innovative index-weight optimization method based on the Lagrange conditional extremum algorithm.The fuzzy technique for order preference by similarity to the ideal solution is applied to rank wind project alternatives considering functionality and proportionality of the system.Moreover,the sensitive analysis is applied to verify the robustness of the proposed method.The applicability of the method is demonstrated on a case study from China,where three main wind projects are analytically compared and ranked.The results indicated that the sustainable level of calculated wind power can provide a reference point for the planning and operation of the wind project.The results show that the proposed method is of both theoretical significance and practical application in engineering.