To enhance heat transfer, as well as prevent and remove fouling, a vertical two-pass circulating fluidized bed evaporator with a baffle has been designed and built. The uniformity of particle distribution in the evaporator significantly influences the performance of fouling preventing and removing. The joint effects of baffle height and liquid level in the evaporation chamber on the particle distribution and pressure drop are systematically investigated with a Charge-Coupled-Device image measurement and acquisition system. At a certain baffle height, appropriate increase of liquid level is conducive to the uniform distribution of particles. In the case of a small difference between the baffle height and liquid level, the increase of liquid level can improve the uniformity of particle distribution. At a large height difference, the influence of liquid level is obviously restricted by the circulation flow rate. The pressure drop fluctuates slightly with the increase in baffle height and liquid level. (C) 2020 Elsevier B.V. All rights reserved.