PVC is a thermoplastic resin that cannot be processed on its own due to its very low thermal stability and high melt viscosity. Therefore, it is necessary to prepare an intermediate product where a variety of additives are mixed with the PVC resin to form a “dry-blend” that can be later melt-compounded or processed into a finished article. The unit operations present in the compounding of PVC involve delivering and storage of raw materials, feeding and spraying of all ingredients into a special mixer, mixing and heating the materials to create a dry-blend, then cooling and transferring the dry-blend to storage or to a conversion process such as molding, extrusion or calendering.