Pulp and Paper
Pulp and Paper
No damage when in steam turbine by-pass
In the process of making paper, steam is used in the drying section of the paper mill to dry the rolls of sheet paper; compressed sheets are routed over steam heated drying cylinders to evaporate moisture from the sheets. If the paper sheet in the dryer tears, the steam supply to the heater stopped immediately resulting in a steam turbine by-pass occurrences.
In this situation all of the steam flow to the steam turbine inlet will be routed directly to the deaerator. The deaerator itself has to be able to handle a sudden large increase in steam flow. In tray type deaerators this often results in severe damage to the tray section.
This problem does not exist in a Stork spray type deaerator since it has no trays and also because the steam flows into the deaerator under the water level via the steam rake. The steam turbine by-pass case is taken account of during the design of the deaerator and the steam rake will be designed in such a way that it can successfully handle the suddenly higher steam flow during by-pass mode. In addition, the water bulk in the deaerator dampens the effect of increased steam flow thus providing for flawless operation during by-pass situations.
System designers for pulp and paper plants often request large deaerator retention times. Retention times of 15-30 mins. are not unusual. The combination of retention time sizing and a relatively large demin water flow can result in deaerators of significant dimensions. The integral design of the Stork spray type deaerator offers benefits due its more compact design compared to a tray type deaerator. This means that the client can save on civil building and installation costs.
As in any other production environment, the availability of equipment is of the utmost importance to ensure continuity of production, (in this case of pulp/paper).
Due to the robust design of the Stork spray type deaerator, the tray-less design and because sprayers do not need to be replaced, the resulting availability is far superior to that of a tray type design.
New Klabin project
|Type:||Pulp and Paper||Type:||High Energy Recovery Boiler for a paper mill|
|Output:||1.5 million tons of paper/year||Output:||Firing capcity of 11.600 tons of dry solids per day|
(equivalent to daily average electric power of a European
city of one million inhabitants
|Features:||Features:||Biggest recovery boiler worldwide|
|Deaerator size:||Ø4700 x 37500 mm||Deaerator size:|
Ø6000 x 39594 mm
|Year of delivery:||2014||Year of delivery:||2015|
|Outlet flow:||1500 t/h||Outlet flow:|
|Operating pressure:||2.63 Barg||Operating pressure:||4.16 bara|
|Gross volume:||503 m3||Gross volume:|
|Total weight:||Total weight:||195 tons|
|Performance:||7 ppb||Performance:||7 ppb|
|Design code:||ASME VIII Div 1||Design code:||ASME VIII Div. 1 Ed. 2010, Addenda 2011 with U-stamp|