熔融法处理垃圾焚烧飞灰过程中可溶盐富集规律研究

Study on Enrichment Rule of Soluble Salts in the Process of Incineration Fly Ash Treatment by Melting Method

针对传统技术将垃圾焚烧飞灰进行资源化处置时,飞灰中可溶盐组分钠、钾、氯、硫含量过高会引起设备腐蚀、堵塞以及影响产品性能的问题,本研究利用高温熔融法处理飞灰,使飞灰中钠、钾、氯、硫等可溶盐物质向浓缩灰中富集,避免上述问题产生的同时,为后续可溶盐资源回收提供条件。结果表明:飞灰原料中可溶盐组分挥发率依次为氯(59.19%~70.21%)>钾(37.71%~62.09%)>钠(25.52%~55.89%)>硫(21.93%~42.79%),表明可溶盐组分在烟气中大量富集。对预除尘系统、急冷降温系统及布袋除尘分别收集的3种浓缩灰进行分析发现,上述可溶盐最主要富集在布袋除尘收集的浓缩灰中。相对于原料,上述3种浓缩灰中各成分的含量倍数分别为:钠1.08~2.46、1.90~2.86、4.00~5.03倍;钾1.27~2.59、2.79~3.37、4.73~6.72倍;氯1.56~3.28、2.66~3.69、3.30~4.91倍;硫1.17~3.00、1.73~3.16、3.78~5.96倍。

Excess soluble salts in fly ash containing sodium,potassium,chlorine and sulfur will result in the erosion and blocking of equipments or affect product performance when using the traditional technologies to recycle the waste incinerated fly ash. High temperature melting method was used to deal with fly ash,which could made soluble salts such as sodium,potassium,chlorine and sulfur were enriched into concentrated ash. Therefore,it provided conditions for the subsequent recovery of soluble salts,while avoided the above problems. The results indicated that volatile rate of chlorine,potassium,sodium and sulfur in fly ash was 59.19%~70.21%,37.71%~62.09%,25.52%~55.89% and 21.93%~42.79%,respectively,suggesting excess accumulation of them in exhaust gas. Three kinds of concentrated ash collected by pre-dedusting system,quench cooling system and bag filter were analyzed. As a result,the soluble salts were mostly enriched in the fly ash collected by bag filler.The concentration of sodium in the concentrated fly ashes selected from the processes of pre dusting, quench cooling and bag dust removal was1.08~2.46,1.90~2.86,4.00~5.03 times higher than that in the raw waste incineration fly ash,respectively;For potassium,the times were 1.27~2.59,2.79~3.37,4.73~6.72,respectively;For chlorine,the times were 1.56~3.28,2.66~3.69,3.30~4.91,respectively; For sulfur,the times were 1.17~3.00,1.73~3.16,3.78~5.96,respectively.