Multi-stage steam jet vacuum systems

Process management in multi-stage steam jet vacuum systems

The fouling of the processing media is one of the aspects that governs the process design, especially the choice of the condensers. The type of process design and the choice of materials are adapted to suit the requirements in each single case.

The key characteristics of process design in steam jet vacuum systems are:

• mixing condensers or surface condensers
• mixing condensers with cooling water or process medium
• steam jet vacuum systems with mixing condensers and closed cooling water cycle (not susceptible to soiling and little waste water is produced)
• surface condensers with condensation on the shell side or on tube side
• surface condensers with fixed tube sheets, or removable tube bundles (floating head or u-tube design)
• unheated, partially heated or fully heated steam jet vacuum ejectors
• steam jet vacuum ejectors with steam or organic vapours as the motive medium
• the quality of the materials in the systems is primarily driven by how corrosive the media used is; in addition to all grades of steel and stainless steel, high-alloy materials, or graphite, or suitable coatings are used

Advantages:

Steam jet vacuum systems provide extensive advantages:

• no mechanically moveable parts
• besides standard materials a wide range of special materials can be used for manufacturing ejectors
• maintenance-free operation
• top levels of availability (even after lengthy downtime)
• very reliable in all respects (e.g. no risk of cavitation)
• little safety technology and process monitoring are required
• hermetically sealed, without any additional devices needed
• no potential sources of ignition, therefore the EU explosion directive ATEX must not be applied