Handbook of Solvents - George Wypych - ChemTech - Ventech!

402 Seung Su Kim, Jae Chun Hyun
Figure 7.3.17. Schematic of HADES. HADES contains several sections. [Adapted, by permission, Vinjamur and
Cairncross, Presented at the AIChE national meeting, Dallas, Texas, November 1, 1999].
Figure 7.3.18. Schematic of sample chamber of HADES. Dry nitrogen flows in from the port on the left side and
the exhaust flows out through the port on the right to a FID. [Adapted, by permission, Winward and Cairncross, 9th
International Coating Science and Technology Symposium, Delaware, USA, May 17 - 20, 1998, pp.343 - 346].
solvent vapor concentration times the gas flow rate, and the solvent loss is found by integrating
the evaporation rate.
The HADES is consisted of several sections as shown in Figure 7.3.17; gas handling
system, a sample chamber and several process measurements. 52,57 The nitrogen gas flows
into the sample chamber as shown in Figure 7.3.18. The temperature and rate of gas flow are
controlled and the gas temperatures before and after the coating sample tray are measured
with thermocouples. The coating temperature is measured with thermocouple which is installed
at the coating sample tray, and the solvent laden gas flows into the total hydrocarbon
analyzer which is equipped with flame ionization detector (FID). The concentration of solvent
at the exhaust gas is measured by total hydrocarbon analyzer, which is calibrated with
known concentration of solvent vapor (via solvent bubblers).
Figure 7.3.19 and Figure 7.3.20 show the examples of HADES running. 52 Figure
7.3.19 shows the measured solvent concentration of the PVAC-toluene system, as shown in
the figure the residual solvent decreases according to the rate of airflow. However, over the
36 cm/s of airflow rate the drying rate wasn’t changed, above this airflow rate, the residual