4. Synloop Boilers

4. Synloop Boilers

The KNM Group’s Borsig HOT/COLD tubesheet design for synloop waste heat boilers are highly demanded for their waste heat recovery systems in ammonia plants. U-tubes with hot and cold ends are alternately arranged. The hot shank is surrounded by cold shanks.

Advantage of this design is that the tubesheet and the hot end tube wall temperature inside the tubesheet can be kept below 380°C to avoid nitriding and to use ferritic tubes. As a result the inlet ends of the tubes inside the tubesheet as well as the whole tubesheet itself are at gas outlet temperature.

The U-tubes are arranged in such way that each inlet is located adjacent to an outlet end. Inlet end ferrules protrude approx. 50 mm from the thick tubesheet into the channel and are fitted to a dummy tubesheet, which is connected to an internal gas chamber of incoloy for the hot incoming gas.