Manufacturers of wear-resistant ash transfer elbows discuss the causes of wear in wear-resistant pipes

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In pneumatic ash conveying pipelines, the parts that suffer the most wear are the wear-resistant ash conveying elbows. The concentration of ash and slag on the outside of these elbows is high, resulting in relatively severe erosion and wear there. However, the flow direction of the medium at the elbows is complex; each case must be analyzed individually, and different wear-resistant elbows are used depending on the operating conditions. 1. In some power plants, the coal quality is good; after combustion, what remains is mainly ash. Since the ash does not cause severe wear such as erosion, impact, or scratching on the pipes, ceramic wear-resistant elbows can be used. For straight pipes, carbon steel pipes can generally be used. 2. Due to the contraction and expansion effects inherent in the elbows of the pneumatic ash transport pipelines, as well as the formation of vortex areas, the abrasion caused by ash on the inner side of the elbows is **greater than the abrasion on the outer side. Although inertia causes the ash concentration on the outside of the elbow to increase, the contraction effect of the elbow and the formation of vortices result in an **increased flow velocity on the inside of the elbow, leading to multiple scouring events; this is the main reason for the severe wear on the inside of the elbow. When there is a significant amount of ash residue, wear-resistant backpack elbows should be used; these consist of ceramic elbows to which a wear-resistant backpack is added to the back side, thereby providing wear resistance. 3. As the concentration of ash and slag during operation, the flow velocity in the pipes, and the size of the ash and slag particles increase, the wear rate of the pipes also increases accordingly. When the pressure increases, dual-metal wear-resistant elbows or ceramic-ring wear-resistant elbows have to be used; these types of wear-resistant elbows are expensive but offer excellent wear resistance. Therefore, during the design and installation of pneumatic ash transfer pipelines, the piping layout should be arranged reasonably to minimize the use of elbows. Meanwhile, in order to increase the service life of the elbows in these pipelines, it is recommended to adopt anti-wear measures such as pre-strengthening, thickening, or using eccentric elbows, as well as employing wear-resistant materials or composite materials, such as ceramic composite wear-resistant pipes or ceramic composite wear-resistant elbows. Secondly, during design and installation, efforts should be made to ensure a proper matching between the ash discharge volume, water pumps, motors, and pipelines, so as to maintain an appropriate ash-to-water ratio and pipeline flow velocity, thereby reducing pipe wear.