燃煤锅炉掺烧是一种经济可行的污泥处置方式,由于造纸污泥有机质含量较高,采用造纸厂内已建成的燃煤供热锅炉掺烧造纸污泥,既可以减少造纸厂处理污泥的成本,又能利用污泥热能。掺烧造纸污泥可能会使锅炉产生的烟气和灰渣等固体废物中的污染物有所变化。利用造纸厂2×300MW机组锅炉进行掺烧造纸污泥试验,检测产生污染物的变化情况。掺烧试验共掺烧造纸污泥755t,燃煤与掺烧污泥的掺混比为22∶1,混合燃料相比燃煤热值稍下降。掺烧试验持续3d,对烟气、干化污泥、炉渣和粉煤灰进行样品采集,共采集掺烧前3个烟气样品、3个干化污泥样品,各采集1个炉渣粉煤灰的空白样品,共采集掺烧后6个烟气样品、16个炉渣样品及50个粉煤灰样品。检测结果显示,烟气中常规性气体污染物如NOx增加1.5倍,SO2浓度略增加,检测出重金属Ni、Zn、Ba、Se、Cr、Mn、Sb、Pb、Cu,其中重金属Ba和Zn浓度较高,空白组烟气未检测出二噁英,掺烧组二噁英类平均质量浓度为1.20pg/m3(以TEQ计)。相比空白组,掺烧后炉渣中Pb浓度增加最明显,增长2.5倍;而Cu、Ni、Co、Al、Ti重金属浓度下降,空白组炉渣中二噁英质量分数为2.10pg/g,掺烧组炉渣中二噁英质量分数为2.00pg/g;相比空白组,粉煤灰中重金属元素Ba、Mn、As浓度增加明显,增长1.5~2.0倍,而Cu、Zn、Ni、Pb、Co、Ti、Al浓度下降,空白组粉煤灰中未检出二噁英,掺烧组粉煤灰中二噁英质量分数为2.00pg/g。本次掺烧试验产生的污染物均未超过国家标准限值。

The co-combustion of paper mill sludge in coal-fired boilers presents an economically viable sludge disposal method. The paper mill sludge contains a lot of organic matter. Based on the reason, the coal-fired heating boiler that built in the paper mill to burn thepaper sludge was used in the experiment. The co-combustion can reduce sludge treatment costs and utilize the thermal energy present inthe sludge.Co-firing paper mill sludge in the boiler has the potential to alter the composition of pollutants in solid wastes like flue gas, furnace slag, fly ash. A co-firing test was conducted using a 2×300 MW unit boiler in a paper mill. A total of 755 tons of paper mill sludgewas blended with a coal-to-sludge ratio of 22 ∶ 1. The calorific value of the mixed fuel showed a slight reduction compared to coal. Theblending test lasted for 3 d. Samples of flue gas, dried sludge, slag and fly ash were collected. 3 flue gas samples and 3 dried sludge samples were collected before blending, 1 blank sample of slag and fly ash was collected, and 6 flue gas samples, 16 slag samples and 50 flyash samples were collected after blending. The results indicate that conventional gaseous pollutants in the flue gas such as NOx increases by1.5 times, SO2 concentration increases slightly, and heavy metals Ni, Zn, Ba, Se, Cr, Mn, Sb, Pb, Cu are detected. The most prevalentheavy metals are Ba and Zn. PCDD/ Fs are not detected in the blank flue gas samples, with an average concentration of 1.2 pg/ m3(inTEQ) in the co - firing group. Following co - firing, the furnace slag exhibits a notable increase in Pb concentration by 2. 5 times,while concentrations of Cu, Ni, Co, Ba, and Mn decreases by 1.5 to 2.5 times. PCDD/ Fs concentrations remain within permissible limitsin both groups. The concentration of heavy metal elements in fly ash shows significant variations, with elements such as Ba, Mn, and Asincreasing by 1.5 to 2.0 times, while others decreases compared to the blank group. PCDD/ Fs are not detected in the coal fly ash of theblank group, and the concentration of dioxins in the fly ash of the mixed-burning group is 2 pg/ g. All pollutants generated during this cofiring test remains within the prescribed limits set by Chinese national standards.

0 引言

1 试验

   1.1 试验原料及设备

   1.2 燃料的理化特性

   1.3 工程试验方法

   1.4 样品分析方法

   1.5 样品XRD分析

2 结果与讨论

   2.1 烟气中污染物排放特性

   2.2 灰渣中污染物的排放特性

3 结论