Apparatus and process for heating steam

An apparatus for heating steam formed from cooling water in a heat exchanger for hot gas, comprising a primary heat-exchanger vessel having a compartment for cooling water, an inlet for the gas to be cooled, an outlet for cooled gas, an outlet for heated steam and a collecting space for maintaining generated steam;

• at least one primary evaporator tube positioned in the compartment for cooling water and fluidly connected to the inlet for the gas to be cooled;
• at least one steam tube for withdrawal of generated steam from the collecting space for maintaining generated steam via a steam outlet of said collecting space;
• at least one secondary tube-shell heat exchanger vessel, ‘super heater module’, positioned in the compartment for cooling water, wherein the generated steam is further heated against partially cooled gas from the primary evaporator tube;
• wherein the primary evaporator tube is fluidly connected to the tube side of the super heater module and the steam tube for withdrawal of generated steam is fluidly connected to the shell side of the super heater module such that heat exchange takes place substantially co-current;
• and
• a secondary evaporator tube positioned in the compartment for cooling water and fluidly connected to the gas outlet of the super heater module at one end and connected to the outlet for cooled gas at its downstream end.