"釜式反应器" can be translated into English as "stirred-tank reactor" or "batch reactor" (though "batch reactor" more specifically emphasizes the batch operation mode, while "stirred-tank reactor" is a broader term that often encompasses the design featuring a stirred tank, which is characteristic of 釜式反应器).
In most contexts, especially when emphasizing the reactor's structure with a stirred tank, "stirred-tank reactor" is the more appropriate and commonly used translation.