An improved pneumatic particulate conveyance system including a particulate diffuser plate is disclosed. The assembly includes a pipeline with one or more particulate inlets for introducing solid particulates to a prime mover, wherein the pipeline has at least one particulate diffuser plate located within the pipeline. The particulate diffuser plate has a length which runs parallel to the prime mover and occludes at least a portion of a particulate inlet so as to increase the surface area exposed to the conveying air, thus resulting in a more efficient momentum transfer to the particulate.The plate used in the assembly further includes an arcuate trailing edge so as to encourage more particulate falling into the middle (i.e., the higher velocity portion of the profile) of the prime mover. In addition, depending upon the diameter and length of the pipeline, the assembly of the present invention may include a plurality of particulate diffuser plates so as to further increase the amount of exposed surface for momentum transfer to the particulate being conveyed.