Improving the slurry fuel preparation performance to recycle municipal sewage sludge by combined alkali and ultrasonication pretreatment

详细信息    查看全文

• 作者：Ruikun Wang ; Zhenghui Zhao ; Jianzhong Liu ; Yukun Lv…
• 关键词：Sludge recycling ; Coal water slurry ; Alkali treatment ; Ultrasonication ; Waste management
• 刊名：Research on Chemical Intermediates
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：42
• 期：10
• 页码：7345-7358
• 全文大小：562 KB
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Chemistry
  Catalysis
  Physical Chemistry
  Inorganic Chemistry
  
• 出版者：Springer Netherlands
• ISSN：1568-5675
• 卷排序：42

文摘

Municipal wastewater sludge (hereafter, sludge) is economically recycled by mixing with coal to prepare slurry fuels, called coal sludge slurry (CSS). However, raw sludge needs to be pretreated before being prepared as CSS because of its high viscosity. Alkali and ultrasonication pretreatment can effectively disrupt the sludge flocs and improve slurrying performance. The alkali pretreatment method takes a long time but has a low cost, whereas the ultrasonication pretreatment method needs a high energy input but takes a short time. This study combined these two methods with complementary advantages to reduce the sludge pretreatment time and ultrasonication energy demand to improve the slurrying performance for sludge. Results showed that, compared with only alkali and only ultrasonication, the combined alkali and ultrasonication pretreatment method had stronger effects on reducing slurry viscosity. The characteristic viscosity η_c of CSS prepared by raw sludge was 1663.60 mPa s. It was reduced to 1033.44 and 1472.10 mPa s, respectively, after the sludge was only pretreated by NaOH and Ca(OH)₂ at a dosage of 10 % dry sludge (DS) for 2 h, while it was reduced to 1205.43 mPa s after the sludge was only pretreated by ultrasonication of 30 kJ/g DS. After combined pretreatment, η_c of CSS was reduced to 774.98 mPa s (NaOH of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS) and 1083.24 mPa s (Ca(OH)₂ of 10 % DS for 2 h + ultrasonication of 30 kJ/g DS), respectively. Apparently, the combined method can effectively decrease the alkali dosage or the ultrasonication energy input.