Support apparatus for a chemical reactor vessel comprises a mounting system comprising a collar device (221) arranged for closure around the chemical reactor vessel, and a mounting unit (200) having a member (212) with a hollow, semi-cylindrical receiving portion arranged to receive and support the chemical reactor vessel when fitted with the collar device. The collar device has three radially outwardly extending lugs (223A, 223B, 223C). An upper surface of the member (212) is provided with recesses for receiving and supporting lugs 223A and 223C. A slot in the hollow, semi-cylindrical receiving portion is arranged to receive and support the lug (223B). A chemical reactor vessel fitted with the collar device may be mounted on the apparatus without the need for manual handling of the apparatus, allowing two hands to be used for lifting and mounting the vessel. The lugs (223A, 223B, 223C), recesses and slot cooperate to prevent rotation of the vessel when mounted on the apparatus.