摘要 |
<p>A method and apparatus are disclosed for controlling a temperature within a reactor vessel such as an autoclave operating at elevated temperature and pressure. The apparatus includes a preheating vessel for preheating a feed material such as an aqueous slurry. The preheating vessel forms part of a preheating control system which provides the primary means of temperature control within the reactor vessel, and the reactor temperature is used as the setpoint for the preheating control system. The apparatus also comprises secondary means for heating and cooling the reactor. The feed material temperature is increased or decreased by the preheating control system, based on the reactor temperature. This is sufficient to heat or cool the reactor under most process conditions. Where the preheating control system is at or-near its capacity for heating or cooling, the secondary heating or cooling means is activated to bring the reactor temperature within an optimum range.</p> |