Charun Bunyakan, Somtip Danteravanich, Juntima Chungsiriporn, and Janya Intamanee

pp. 79 - 89

Abstract

Ammonia removal is an important step in skim rubber sheet production. The most commonly used
technique to remove ammonia from skim latex is a channel flow method where the skim latex is forced to
flow through the shallow and long channel. This technique requires large space and long operating time.
This research was aimed to investigate the influence of ammonia volatilization from open channel. The
ammonia volatilization from open channel was performed in an open channel 0.23 m wide and 20 m long.
The water flow rate through the channel was varied from 10 to 50 L/min. The overall mass transfer coefficients of ammonia were determined and compared to those obtained from ammonia volatilization from
water due to liquid agitation and air blowing which were previously investigated. The results have shown
that the mass transfer coefficients of ammonia by the channel flow method were significantly higher than by liquid agitation but lower than those by air blowing method, as expected. The magnitude of mass transfer
coefficient of ammonia obtained suggests that the ammonia volatilization rate from water due to flow effect
is high enough for ammonia removal from skim latex. In order to reduce space and minimize operating time
of the channel flow method, we , however, recommend the use of combined channel flow and the air blowing
method. From this work, we have found that both the flow effect and the air velocity over water surface
significantly enhance the mass transfer coefficient of ammonia. Thus, the combination of these effects will
definitely enhance the ammonia transfer rate. The removal efficiency of this combined system will definitely
be higher than that of any conventional one (agitation or open channel flow).