稠油硫酸盐热化学还原生成H2S实验研究

为了研究稠油注汽热采过程中生成H₂S机理，以Na₂SO₄，CaSO₄，MgSO₄，Fe₂（SO₄）₃，Al₂（SO₄）₃与稠油硫酸盐热化学还原（TSR）实验为基础，探究稠油TSR生成H₂S机理。实验表明，不同硫酸盐与稠油反应生成H₂S不尽相同，硫酸盐的阳离子所带电荷数决定TSR反应程度的难易，电荷数越多越容易进行反应，且H₂S生成量顺序为Al₂（SO₄）₃>Fe₂（SO₄）₃ > MgSO₄ > CaSO₄ > Na₂SO₄，但生成的烃量顺序为Fe₂（SO₄）₃ > Al₂（SO₄）₃ > MgSO₄ > CaSO₄ > Na₂SO₄。与其他硫酸盐不同的是，由于Fe₂（SO₄）₃的氧化性，Fe³⁺可能与生成的H₂S进一步反应。通过傅里叶红外变换光谱（FT-IR）对固相检测发现，不仅存在金属氧化物（CaO，MgO，Fe₂O₃，Al₂O₃）还存在FeS₂。最后，通过对MgSO₄油相硫含量的检测发现，反应后硫含量高于原油硫含量，证明了无机硫向有机硫的转化。

An Experimental Investigation of H2S Production by Thermochemical Sulfate Reduction in Heavy Oil

The mechanism of H₂S formation during heavy oil recovery by steam injection was investigated by reacting five sulfates (Na₂SO₄, CaSO₄, MgSO₄, Fe₂(SO₄)₃, and Al₂(SO₄)₃) with heavy oil via thermochemical sulfate reduction(TSR). Significant variations were observed in the production of H₂S depending on the type of sulfate reacting with the heavy oil, as the number of charges carried by the sulfate cation governed the ease of the TSR reaction. More strongly charged sulfate cations facilitated the TSR reaction. The H₂S yields of the sulfates followed the order:Al₂(SO₄)₃ > Fe₂(SO₄)₃ > MgSO₄ > CaSO₄ > Na₂SO₄. However, the hydrocarbon yields were as follows:Fe₂(SO₄)₃ > Al₂(SO₄)₃ > MgSO₄ > CaSO₄ > Na₂SO₄. Fe₂(SO₄)₃ is unique among the sulfates as it can react with H₂S due to its oxidizing property. The solid-state Fourier transform infrared spectroscopy (FTIR) analyses showed that FeS₂ was present in addition to several metal oxides (CaO, MgO, Fe₂O₃, and Al₂O₃). Finally, the sulfur content of the oil phase with the TSR reaction of MgSO₄ was analyzed, and it was demonstrated that the post-TSR sulfur content of the oil phase was higher than that of crude oil. This confirmed that inorganic sulfur was converted to organic sulfur during the TSR reaction in heavy oil.