Slurry Heating with Direct Steam Injection Heating

To overcome these challenges, Direct Steam Injection (DSI) is a very good approach. Unfortunately, there are some correct ways to apply DSI and some approaches that may not produce desirable results. One of the key factors to successful DSI, is to inject steam at sonic velocity to achieve choked flow.

The problems arise when the steam pressure has been dropped to a point where the steam flow is no longer choked. This can be seen most often at start up and shutdown of externally modulated steam injectors in the form of noise, vibration and hammering. With an external steam valve, there is always a pressure drop before the steam reaches the injector. Some sparger devices use passive springs and tube assemblies that tend to stick, resulting from scale build-up, causing temperature control problems.