Catalytic external heat exchanger
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Does the catalytic external heat exchanger have a slide valve? What’s the use of it?
There are slide valves available, whose function is to adjust the heat extraction load in order to balance the charring constant, as well as to disconnect the external heat exchanger
It depends on the form of heat removal outside. A recirculation type is not necessary; the amount of heat removed can be controlled by adjusting the catalyst circulation rate using a slide valve. This feature is available in our TMP units, but not in those for rapid pyrolysis
It’s to adjust the catalyst circulation rate and control the reaction temperature!
Of course it’s useful; firstly, it can adjust the load of the external heat exchanger. Second is to control the catalyst inventory in the external heat exchanger. Third, in the event of a tube rupture due to buckling, the external heat exchanger can be disconnected from the system for maintenance.
The key is the first two functions; as for the last one, even if there is a hot catalyst inside the tube, it’s not possible to remove the external heat exchanger
External heat exchangers are available in both valve-controlled and valve-free versions, and both are widely used in practice. Overall, valve control is a bit more flexible. Currently, the external heat extraction load for large-scale catalysis is quite high. Some systems are equipped with two external heat extractors: one equipped with a valve and the other without one. The external heat extractor without a valve operates at full capacity, while the one with a valve is used to adjust the heat extraction load, providing greater flexibility. In fact, with a valveless external heat exchanger, proper design ensures that regulation is not an issue; it’s just that the range of operational conditions is limited, and near the upper limit of load, the regulation seems to become ineffective.