Experimental Study On Abrasive Wear Of Circular Tube In Low-speed Particles Flow

In the production process of energy-intensive industries such as power,metallurgy,and chemicals,there are a large number of products or by-products in the form of high-temperature particles.These particles contain a considerable amount of high-quality waste heat.Recycling this waste heat is feasible for energy conservation.In the process of waste heat recovery for high-temperature particles,the wear of the heat exchange tubes is accompanied by the particles,which directly affects the feasibility and economics of the industrialization of the blast furnace slag waste heat recovery technology.Aiming at the abrasion problem of heat exchange tubes in the blast furnace slag particle self-flow bed waste heat boiler,this article builds abrasive wear test bench based on an in-depth analysis of its working conditions,and sets particle sizes,temperature,burial depth and relative speed as investigation factors.This article analyzes the sensitivity of each factor to the wear of heat exchange tube,and studies the wear law of heat exchange tubes in order to provide guidance for the design parameters and operating parameters of the particle self-flow bed waste heat boiler.Regression is carried out based on experimental data to obtain empirical formulas,and to estimate the life of the heat exchange tubes.The specific research contents and conclusions are as follows.Aiming at the abrasion problem of heat exchange tubes in the blast furnace slag particle self-flow bed waste heat boiler,this article builds abrasive wear test bench based on an in-depth analysis of its working conditions,and sets particle sizes,temperature,burial depth and relative speed as investigation factors.The wear law of the heat exchange tubes is investigated in order to provide guidance for the design parameters and operating parameters of the particle self-flow bed waste heat boiler.Regression is carried out based on experimental data to obtain empirical formulas,and to estimate the life of the heat exchange tubes.The specific research contents and conclusions are as follows.(1)The sensitivity of the four factors to the influence of wear is analyzed through orthogonal experiments.The sensitivities in descending order are burial depth,particle size,relative speed,and temperature.(2)The increase of the particle size reduces the number of particles in contact with the steel tube,which increases the friction between the two and the wear,and the wear rate increases.The wear rate decreases first and then increases with increasing temperature,which is the result of the plasticity of the steel tube changing with increasing temperature.As the burial depth increases,the force between the blast furnace slag particles and the surface of the heat transfer tube increases,and the wear rate increases.The increase of speed increases the force between the blast furnace slag particles and the surface of the tube.At the same time,the number of particles in contact with the tube per unit time increases,increasing the wear stroke,increasing the possibility of material shedding,and increasing the wear rate.(3)By comparing the surface morphology of the steel tube before and after abrasion,the results show that the wear occurs only in the first half of the steel tube,and the surface morphology changes greatly.The cutting wear scars caused by sandpaper grinding before wear completely disappear,and some scars are saved only at a speed of 4.8mm/s.On the front of the wear,the particles have a larger angle of attack.And the wear is mainly caused by the furrow effect of the particles on the steel tube.The surface appears as randomly distributed pits,and there are also a few cutting wear marks.On the side,the wear mechanism is mainly micro-cutting,and obvious cutting wear marks can be observed.(4)The empirical equation is obtained by the regression analysis of the experimental data,and the fitting degree is 86.8%,which is significant at the 1%level.(5)The estimated life of the heat exchange tubes in the blast furnace slag selfflow bed waste heat boiler is 42027h(4.8 years),which is slightly lower than the empirical value and meets the basic requirements of industrialization.