## 2 Experiment
### Experimental Results and Discussion  
#### 2.4.1 Aquathermolysis Experiments  
Table 2 shows the results of gas chromatography for the gas products. It can be seen from Table 2 that the concentrations of H\({}_{2}\)S, CO\({}_{2}\), and H\({}_{2}\) were 0.00013% (1.3 ppm), 24.487%, and 38.52%, respectively, at 270 \({}^{\circ}\)C and 0.5 d.  
The possible reasons for the presence of H\({}_{2}\)S, CO\({}_{2}\), and H\({}_{2}\) in the gas products are shown as follows [12]:  
\[\text{Organosulfur}\xrightarrow{\text{Aquathermolysis}}\text{Alcohol}+\text{ Mercaptan}+\text{H}_{2}\text{S} \tag{1}\]  
\[\text{Alcohol}\xrightarrow{\text{Aquathermolysis}}\text{Aldehydes} \tag{2}\]  
\[\text{Aldehydes}\xrightarrow{\text{Aquathermolysis}}\text{Carbon Monoxide}+\text{Hydrocarbon} \tag{3}\]  
\[\text{Carbon monoxide}+\text{Steam}\xrightarrow{\text{WGSR}}\text{Carbon dioxide}+\text{Hydrogen} \tag{4}\]  
\[\text{Hydrogen}+\text{Organosulfur}+\text{Mercaptan}\xrightarrow{\text{ Hydroosulfurization}}\text{H}_{2}\text{S} \tag{5}\]  
According to Equations (1)-(5), it can be seen that the C-S bond of the S-containing organic compound of heavy oil broke in the aquathermolysis reaction, resulting in the presence of H\({}_{2}\)S, CO\({}_{2}\), and H\({}_{2}\) in the gas products. Of course, many paraffin hydrocarbons and olefins were also detected in the gas products. For example, the concentrations of methane, ethane, and propane were 12.921%, 2.381%, and 2.516%, respectively, while the concentrations of C\({}_{6+}\), pentene, and trans-2-buttene were 3.797%, 1.256%, and 3.658%, respectively at 270 \({}^{\circ}\)C and 0.5 d. Similar results were observed in the other three sets of experiments. The possible reasons are shown as follows: (1) The C-C bond cleavage of asphalt chains and the \(\beta\) scission in the alkyl side chain of aromatics of heavy oil lead to the formation of short olefins and low molecular light hydrocarbon in the aquathermolysis reaction [21,22]. (2) The extraction of steam resulted in the formation of long-chain hydrocarbons (such as C\({}_{6+}\), trans-2-buttene, pentene, and so on) in the gas products [23]. Besides, it can be seen from Table 2 that the H\({}_{2}\)S concentration increases with the increase in temperature. When the reaction time was 0.5 days, the H\({}_{2}\)S concentrations were \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Gas** & **270 \({}^{\circ}\)C, 0.5 d** & **300 \({}^{\circ}\)C, 0.5 d** & **270 \({}^{\circ}\)C, 2 d** & **300 \({}^{\circ}\)C 2 d** \\ \cline{2-5}
**Composition** & **Volume, \%** & **Volume, \%** & **Volume, \%** & **Volume, \%** \\ \hline H\({}_{2}\) & 38.52 & 39.437 & 39.519 & 40.265 \\ CO\({}_{2}\) & 24.487 & 26.935 & 27.192 & 30.861 \\ CO & 0.499 & 0.812 & 1.253 & 1.476 \\ Methane & 12.921 & 15.446 & 16.507 & 18.792 \\ Ethane & 2.381 & 3.419 & 2.861 & 3.906 \\ Ethylene & 3.22 & 2.795 & 2.184 & 0.237 \\ Propane & 2.516 & 2.824 & 3.11 & 3.618 \\ Propylene & 2.456 & 1.235 & 1.195 & 0.302 \\ Isobutane & 0.185 & 0.147 & 0.153 & 0.114 \\ N-butane & 0.73 & 0.577 & 0.458 & 0.159 \\ Trans-2-buttene & 3.658 & 2.186 & 2.679 & 0.051 \\
1-buttene & 1.964 & 1.225 & 0.763 & 0.012 \\ Isobutene & 0.928 & 0.254 & 0.278 & 0.035 \\ Pentane & 0.327 & 0.135 & 0.186 & 0.022 \\ Isopentane & 0.154 & 0.086 & 0.095 & 0.037 \\ Pentene & 1.256 & 0.14 & 0.507 & 0.008 \\ C\({}_{6+}\) & 3.797 & 2.343 & 1.056 & 0.093 \\ H\({}_{2}^{2}\)S & 0.00013 & 0.003185 & 0.003029 & 0.01019 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Results of gas chromatography for gas products at different reaction temperatures and times. 0.00013% (1.3 ppm) and 0.003185% (31.85 ppm) at 270 \({}^{\circ}\)C and 300 \({}^{\circ}\)C, respectively. This is due to the fact that with the increase in temperature, the reaction rate accelerated, and the C-S bond was easier to break. In addition, the concentrations of CO\({}_{2}\) and H\({}_{2}\) also varied from 24.487% and 38.52% to 26.935% and 39.437%, respectively.