In the INTERCAT Catalyst Withdrawal System hot spent catalyst is withdrawn continuously into a collection vessel which is very similar to a 200ft3 addition system on load cells. The rate of catalyst withdrawal is dynamically controlled using vessel weight readings and differential pressure control. When the vessel is full, catalyst is automatically transferred to the spent catalyst hopper. The skid contains a specially designed heat exchange module allowing the withdrawn catalyst to be cooled to a specified temperature.
Gases vent from the collection vessel through a Sintered Metal Filter (SMF) and the vessel pressure is regulated by a valve on the clean side of SMF thus eliminating erosion.
Most existing FCC Catalyst Withdrawal Systems are very basic with simple manual control by gate valve and manual carrier air adjustment. High temperatures and poor velocity control result in high erosion rates of valves and lines resulting in frequent maintenance being required with the subsequent risk of hot catalyst spills. Erosion of the throttling device for controlling withdrawal rate is completely eliminated with the INTERCAT Catalyst Withdrawal System by a pressure balance design allowing the use of a simple on/off Everlasting valve.
Infrequent withdrawals also result in large, sudden changes in regenerator catalyst bed level which can have a significant impact on unit operation and flue gas emissions. With the INTERCAT Catalyst Withdrawal System withdrawal is continuous so bed level can be kept constant.