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Spinbath Degassing System
SPINBATH DEGASSING SYSTEM
For the removal of gasses in spinbath and recovery as combustible "rich gas" (low flow rate with high content of H2S and CS2 above the upper explosion limit).
Features
Low levels of H2S and CS2 in the spinbath circulation are essential for:
- Minimising sulphuric emissions from the spinning machine and the circulation tanks
- Minimising formation of ZnS deposits in the sandfilters
- Less dirt in the circulation system
- Maximising fiber quality
In Detail
The aim of a spinbath degassing system is the removal of dissolved gasses, as they can react to form solid sulphide compositions, which would lead to considerable undesirable deposits in the whole spinbath circulation system. The collection of the highly concentrated gases offers a unique opportunity for recovery of the atmospheric sulphur compounds, for example by catalytic conversion to sulphuric acid.
The spinbath degassing system is designed as two stage vacuum degassing plant. In the upper stage of the degassing column the spinbath is sprayed in by means of a multistage nozzle. The upper stage operates as degassing stage as well as a mixing condenser under vacuum. The pressure is low enough for the dissolved gases to partly escape during spraying, but at the same time high enough for the steam mixture coming from the steam jet apparatus to nearly completely condense before it reaches the upper end of the column.
The partially degassed spinbath solution flows down into the lower stage of the degassing column and is again sprayed by means of a multistage nozzle. At this stage the vacuum is so high that the spinbath solution starts boiling during spraying. The flash vapour and the removed gases are compressed by a steam jet to the pressure of the upper degassing stage. The saturated gases taken out of the top of the degassing column by a vacuum pump are passed through a gas washer, and then compressed to approx. 1 bar by means of a vacuum pump. The highly concentrated rich gas can then be utilised in a recovery plant.
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