College of Environment, Hohai University, Nanjing, 210098, PR China.
College of Environment, Hohai University, Nanjing, 210098, PR China.
Chemosphere. 2022 Aug;300:134467. doi: 10.1016/j.chemosphere.2022.134467. Epub 2022 Apr 1.
In this study, the characteristic of hydrogen production and polycyclic aromatic hydrocarbons (PAHs) transformation during supercritical water gasification (SCWG) of coking sludge (400 °C - 450 °C, 1 min-30 min) were explored. The total gas yield was between 0.62 mol/kg OM and 1.05 mol/kg OM (on dry basis), and the proportion of CH and H was only between 5.41% and 6.44%. PAH content were increased from 194.92 mg/kg to 326.04 mg/kg, and mainly high molecular weight PAHs, which were formed from the Diels-Adler reaction of single aromatic hydrocarbon and the addition reaction of low molecular weight PAHs. High reaction temperature favored more active PAH formation than reaction time. The possible control methods for PAH formation during SCWG of coking sludge was proposed. HO and KOH addition effectively reduce PAHs amount in solid residues by 46.67% and 38.33%, and KOH performed positive effect on hydrogen production. The work revealed that the inhibition of PAHs and hydrogen production were achieved from SCWG of coking sludge with KOH addition.
本研究探索了焦化污泥在超临界水气化（SCWG）过程中制氢和多环芳烃（PAHs）转化的特性（400°C-450°C，1min-30min）。总气体产率在 0.62mol/kgOM 和 1.05mol/kgOM（干基）之间，CH 和 H 的比例仅在 5.41%和 6.44%之间。PAH 含量从 194.92mg/kg 增加到 326.04mg/kg，主要是高分子量 PAHs，它们是由单芳烃的 Diels-Adler 反应和低分子量 PAHs 的加成反应形成的。高反应温度有利于形成更活跃的 PAH，而不是反应时间。提出了可能控制焦化污泥 SCWG 过程中 PAH 形成的方法。HO 和 KOH 添加剂分别有效地减少了固体残渣中 PAHs 的含量，达到了 46.67%和 38.33%，并且 KOH 对产氢有积极影响。该研究表明，通过向 SCWG 中添加 KOH，可以实现对焦化污泥中 PAHs 的抑制和产氢。
