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STUDY OF THE HYDROLYSIS REACTION OF THE COPPER-CHLORIDE HYBRID THERMOCHEMICAL CYCLE USING OPTICAL SPECTROMETRIES
Experimental results
Proof of chlorine formation
The experiment is run first at 118°C to remove water from the initial hydrated CuCl 2 , 2H 2 O commercial
product. After around one hour, water vapour is generated at a temperature close to 390°C The
formation of HCl is monitored by conductimetry. No chlorine is observed. At a time T, a temperature
jump is made to reach 530°C, the formation of molecular chlorine is then identified by its spectral
absorbance. The amount of chlorine increases and then decreases when 530°C is reached.
Figure 3: Chronogram of the experiment: temperature,
conductimetry and chlorine absorbance versus reaction time
540
35000
490
440
Temperature
Conductivity
Chlorine concentration
30000
25000
Temperature °C
390
340
Temperature rise
20000
15000
290
10000
240
HCl generation
Chlorine generation
5000
arbitrary units
190
14:24 14:38 14:52 15:07 15:21 15:36 15:50 16:04
Time
0
Figure 4: Absorption spectra of molecular chlorine versus temperature between 390 and 530°C
optical density
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
300 320 340 360 380 400
Wavelength (nm)
Hydrolysis reaction at 390°C
The hydrolysis reaction is then realised at 390°C in order to avoid chlorine formation. The solid
product which is formed is analysed using DRX. Melanothallite Cu 2 OCl 2 appears to be the major
product of the reaction (Figure 5).
246 NUCLEAR PRODUCTION OF HYDROGEN – © OECD/NEA 2010