以Hg<sup>2+</sup>离子为前驱体标定煤热解气中气相元素汞量

曹艳芝; 郭少青; 高丽兵

doi:10.15898/j.cnki.11-2131/td.201703070027

以Hg²⁺离子为前驱体标定煤热解气中气相元素汞量

太原科技大学环境与安全学院, 山西太原 030024

基金项目:
国家自然科学基金资助项目（41372350）；山西省青年科技研究基金项目（201701D221229）

详细信息

作者简介: 曹艳芝, 硕士研究生, 讲师, 从事化石能源中汞等微量元素在热转化过程中的迁移规律研究。E-mail:caoyz@tyust.edu.cn

通讯作者: 郭少青, 博士, 教授, 从事煤中汞等微量元素在煤转化过程中的迁移规律研究。E-mail:guosq@tyust.edu.cn

中图分类号: O614.243;TQ533

收稿日期: 2017-03-07

修回日期: 2017-06-20

录用日期: 2017-08-03

Using Hg²⁺ as a Precursor to Calibrate Gaseous Elemental Mercury from Pyrolysis of Coal

School of Environment and Safety, Taiyuan University of Science and Technology, Taiyuan 030024, China

More Information

Corresponding author: Shao-qing GUO, guosq@tyust.edu.cn

Received Date: 07 March 2017

Revised Date: 20 June 2017

Accepted Date: 03 August 2017

摘要

摘要: 汞易挥发且通常以气态形式在大气环境中迁移转化，检测汞在气相中的含量可为汞的治理工作提供依据，但检测气相汞的技术并不成熟。该项工作需要准确地对气相元素汞量进行测定，而测定的前提是必须具备准确、可靠的标定方法。本研究提出以Hg²⁺离子为前驱体标定煤热解气中气相元素汞量的方法。该方法是基于水溶液中Hg²⁺可被还原剂定量还原成元素汞蒸汽的原理，实现对气相元素汞量的标定。与传统的基于饱和蒸汽原理的标定方法相比，该方法的优点是取样时不易受温度影响，易于精确控制汞量，且避免了实验室内储存汞蒸汽所造成的汞污染。以测定四种煤在热解过程中元素汞的释放量为例考察了本方法的准确性，结果表明本方法具有较好的重复性和适应性。与美国Ontario-Hydro方法分析的结果进行对比，两种方法的相对标准偏差均小于3.0%，说明本研究的标定方法的可靠性较高。
- Hg²⁺ /
- 气相元素汞 /
- 标定 /
- 热解气
Abstract: Mercury is easily volatile and vaporizes in air. The monitor of mercury in gas phase provides insight for developing advanced Hg control technologies. However, the analytical method of gas mercury is rudimentary. In order to determine the gas mercury content, a reliable calibration method is needed. This study provides a method of calibrating gas mercury from pyrolysis of coal with Hg²⁺ as a precursor. The method is based on the principle that Hg²⁺ in aqueous solution can be quantitatively reduced by reductant into elemental mercury vapor to determine the calibration of mercury content in gas phase. Compared with the conventional calibration method based on the saturated vapor principle, this method eliminates the influence of the sampling temperature, the quantity of mercury during sampling can be easily controlled, and pollution of the gaseous mercury stored in the laboratory is avoided. To illustrate the accuracy of the calibration method, the quantity of elemental mercury emission during pyrolysis of four coals were determined. Results show that the method has good reproducibility and adaptability. Compared with the Canadian Ontario-Hydro method, the relative standard deviations of both methods are less than 3.0%, indicating a high reliability of this calibration method.
- Hg²⁺ ion /
- gaseous elemental mercury /
- quantitative calibration /
- pyrolysis gas

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图 1 1#煤样热解过程中元素汞的释放荧光强度值随时间的变化曲线

Figure 1.

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表 1 煤样的工业分析、元素分析以及汞含量

Table 1. Proximate and ultimate analyses, and Hg contents of four coals

煤样编号	Hg含量 (ng/g)	工业分析(%)			元素分析(% daf)
煤样编号	Hg含量 (ng/g)	V_daf	A_as	M_as	C	H	N	S	O^a
1#	179	8.70	12.71	1.31	91.73	3.26	1.21	0.18	3.62
2#	441	37.48	22.55	2.53	71.75	5.82	1.40	0.62	20.41
3#	92	50.21	5.90	0.53	65.91	5.71	1.52	1.18	25.68
4#	213	31.05	13.71	0.28	82.76	5.04	0.83	2.36	9.01
注：as—收到基(以Hg²⁺离子为前驱体标定煤热解气中气相元素汞量)；daf—干燥无灰基；a—差减法。

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表 2 不同汞量标准汞溶液的响应信号值

Table 2. Signals of the standard solutions with different Hg concentrations

汞量 (ng)	元素汞信号值 (10^-3)
50	287.515
100	620.925
250	1315.655
500	2486.493
1000	4984.910

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表 3 在位原子荧光光谱法与Ontario-Hydro法的比较

Table 3. A comparison of the analytical results from on line-AFS and Ontario-Hydro method

样品编号	Hg含量 (ng/g)	响应信号值 (10^-3)	原子荧光光谱法测定的汞量(ng)	Ontario-Hydro 法测定的汞量(ng)	相对标准偏差 (%)
1#	179	844.563	160.2	164.5	2.5
2#	441	2083.597	411.6	405.8	1.5
3#	92	471.966	84.6	82.5	2.5
4#	213	1069.305	205.8	210.5	2.2

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