Abstract:

The reaction and regeneration behavior of melamine (MN), a kind of solid organic amine, with SO₂ was studied. The results show that MN desulfurization rate is above 99% for 140 min at simulated flue gas:0.35%SO₂+ 5%O₂ + N₂, 40℃ and 4% MN (mass fraction). Meanwhile, the breakthrough sulfur capacity (200 mg/m³ SO₂ in outlet flue gas) is 0.33g SO₂/(g MN). The analysis of MN desulfurization and regeneration products by XRD, FTIR, SEM and TG-MS shows that MN reacts with SO₂ to produce melamine sulfite firstly, and then melamine sulfite is oxidized to melamine sulfate partly by oxygen in the flue gas. Adding 0.1% p-diphenylamine can effectively inhibit the melamine sulfite to be oxidized. Melamine sulfite can be heated and regenerated in 75-150℃, but the melamine sulfate cannot be regenerated by heating. The oxidation rate of melamine sulfite decreased from 36% at 5%O₂ to 13% at 5%O₂+ 0.1% p-diphenylamine. When products were heated at 150℃ for 2 h desulfurization, the regeneration rate of melamine increased from 58% at 5%O₂ to 94% at 5%O₂+ 0.1% p-diphenylamine. MN has excellent desulfurization and regeneration performance in the anti-oxidation mode.

Key words: flue gas desulfurization, organic amine, melamine, oxidation, regeneration

摘要：

以固体有机胺三聚氰胺（MN）为脱硫剂，对MN与SO₂反应及再生行为进行研究。结果表明，烟气组成0.35% SO₂+5% O₂+N₂，40℃、4% MN（质量分数）条件下，MN可维持140 min脱硫率>99%，穿透硫容（出口SO₂浓度200 mg/m³）0.33 g SO₂/（g MN）。MN脱硫及再生产物XRD、FTIR、SEM及TG-MS等表征分析表明，MN与SO₂反应首先生成三聚氰胺亚硫酸盐，随后被烟气中的氧气氧化为三聚氰胺硫酸盐，加入0.1%对苯二胺可有效抑制三聚氰胺亚硫酸盐氧化；三聚氰胺亚硫酸盐在75~150℃可加热再生，三聚氰胺硫酸盐不能加热再生。烟气含5% O₂条件下，加入0.1%对苯二胺，三聚氰胺亚硫酸盐氧化率由36%降低至13%，150℃下再生2 h，再生率由58%提高至94%，MN抗氧二次脱硫性能优良。

关键词: 烟气脱硫, 有机胺, 三聚氰胺, 氧化, 再生