| 摘要 |
<p>In installations for the production of phthalic anhydride, the reaction product is precipitated in a solid form on heat exchange surfaces of separators, and is subsequently melted off again, by alternately cooling and heating the separators. The arrangement employed, according to the invention, for transferring the heat and for levelling out the temperature profiles (in which, in the heating phases, there is a peak demand for heating steam, which impedes the useful generation of steam by the exothermic reaction), comprises a heat transfer system consisting of three circuits at different temperatures. A storage circuit (hot oil circuit) at a higher temperature is superposed on the heating circuit operating at a predetermined temperature. Using the hot oil circuit, the separators are provided, during the heating phase, with the heat required to melt off the reaction product. This superposition of 3 circuits at different temperatures produces a levelling of the steam requirement and hence allows more effective utilization of the excess steam.</p> |
