A vertical two-pass circulating fluidized bed evaporator with a baffle is designed and built to enhance heat transfer, as well as prevent and remove fouling. The uniform-distribution of particles in the tube bundle is crucial to the heat transfer performance and fouling preventing of the evaporator. However, previous studies have shown the particle distribution in the down-flow bed is uneven, especially at low circulation flow rate and high baffle height. Therefore, six types of distributors arc designed and installed to adjust the particle distribution in the present research. The effect of operating parameters, such as circulation flow rate, baffle height and particle amount is systematically investigated. The research results show the uniformity of the particle distribution in the down-flow bed can be improved by up to 88.7% with the addition of the appropriate distributor, and the corresponding increase in pressure drop caused by the distributor is no more than 8%. (C) 2020 Elsevier B.V. All rights reserved.