工业高碳富钙型灰对准东混煤结渣特性的影响

王萌; 王毅斌; 谭厚章; 贺力海; 孙瑞; 何光; 杨建伟

doi:10.19906/j.cnki.JFCT.2021001

工业高碳富钙型灰对准东混煤结渣特性的影响

doi: 10.19906/j.cnki.JFCT.2021001

1.
西安交通大学热流科学与工程教育部重点实验室，陕西西安 710049
2.
新疆中泰矿冶有限公司热电厂，新疆乌鲁木齐 830001

基金项目: 国家自然科学基金（51876162，51906198）资助

详细信息

通讯作者:
E-mail: tanhz@mail.xjtu.edu.cn

中图分类号: TQ536.4
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出版历程
- 收稿日期: 2020-09-09
- 修回日期: 2020-10-14
- 刊出日期: 2021-01-29

Effect of industrial ashes with high carbon and calcium-rich on slagging characteristics of blending Zhundong coals

1.
MOE Key Laboratory of Thermo-Fluid Science and Engineering, Xi’an Jiaotong University, Xi’an 710049, China
2.
Thermal Power Plant of Xinjiang Zhongtai Mining and Metallurgy Co., Ltd, Urumchi 830001, China

Funds: The project was supported by the National Natural Science Foundation of China (51876162, 51906198)

More Information

Corresponding author: E-mail: tanhz@mail.xjtu.edu.cn

摘要

摘要: 结合灰熔融测定、固定床和一维沉降炉实验，详细研究两种工业高碳富钙型灰(除尘灰和烘干灰)分别作为添加剂对高、低钠混煤结渣特性的影响。结果表明，原混煤在取样温度1000 ℃时已存在大量无定型硅，升高温度这些组分极易诱发低温共融反应。添入5%除尘灰后混煤煤灰的软化温度提高幅度高达100 ℃，能使混煤煤灰中CaO/SiO₂质量比达到2.5，促使新相硅酸二钙和钙铝榴石生成，能够有效改善混煤的高温结渣倾向。沉降炉实验工况下探针收集灰样中主要物相均为钙铝黄长石，掺入两种添加剂后均可促使含硅物相演变为结晶矿物相，抑制非晶相含硅组分诱发的低温熔融，但添入5%烘干灰后探针表面结渣倾向改善的效果不显著。
- 添加剂 /
- 灰熔融温度 /
- 高钠煤 /
- 混煤 /
- 结渣特性
Abstract: Influence of two kinds of industrial ashes with high carbon and calcium-rich as additives (drying ash and fly ash) on slagging characteristics for blends of high and low sodium coals was studied in detail. Experiments were performed including ash fusion temperature tests, ashing for blending coals with/without additives in a fixed bed furnace and slagging on un-cooled probe in a drop tube furnace. The results show that there is a large amount of amorphous silicon at 1000 ℃ during combustion of raw blending coals, which easily leads to low-temperature eutectic reaction at higher temperature. Adding 5% fly ash can raise soften temperature of the blended coal ashes by 100 ℃, and mass ratio of CaO to SiO₂ in ashes reaches up to 2.5. Dicalcium silicate and grossular are newly generated, which effectively reduce the slagging propensities. The main phase in slag samples collected on the probe is identified as gehlenite after adding two industrial ashes into raw blending coals. The addition of two typical ashes can transform amorphous silicon into its crystalline mineral phase, inhibit formation of low-temperature eutectics. In contrast to the case of adding 5% fly ash, impact of adding 5% drying ash into raw blending coals on slagging tendency of the ash particles on un-cooled probe is insignificant.
- additives /
- ash fusion temperature /
- high-sodium coal /
- blending coal /
- slagging characteristics

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图 1 一维沉降炉实验系统

Figure 1 Schematic diagram of one-dimensional drop-tube furnace

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图 2 添加剂的失重特性曲线

Figure 2 Weight loss curves of additives

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图 3 不同添加剂对入炉煤灰熔融特征温度的影响

Figure 3 Effect of different additives on ash fusion temperature of blending coal

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图 4 固定床1250 ℃煤灰形貌及表面沾污

Figure 4 Morphology of ash and surface contamination at 1250 ℃

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图 5 1150和1250 ℃时混煤煤灰的矿物相变化

Figure 5 XRD patterns of blending coal ash samples at 1150 and 1250 ℃

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图 6 1150和1250 ℃时添加5%除尘灰对混煤灰矿物相分布的影响

Figure 6 XRD patterns of blending coals with 5% fly ash at 1150 and 1250 ℃

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图 7 1150和1250 ℃时添加5%烘干灰对混煤灰矿物相分布的影响

Figure 7 XRD patterns of blending coals with 5% drying ash at 1150 and 1250 ℃

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图 8 沉积探针结渣外观形貌

Figure 8 Morphology of slag on the probe

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图 9 1200 ℃探针截面沉积微观形貌

Figure 9 SEM pictures of slag deposit section at 1200 ℃

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图 10 1200 ℃混煤+5%除尘灰工况EDS图片

Figure 10 EDS pictures of slag deposit section at 1200 ℃

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图 11 沉积渣样的无机矿物分析

Figure 11 XRD patterns of slag deposit

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表 1 煤样元素分析及工业分析

Table 1 Ultimate and proximate analyses of raw coals

	Low sodium coal	High sodium coal
C/%	65.11	73.43
H/%	4.19	3.52
O/%	16.48	18.00
N/%	1.07	0.68
S/%	0.82	0.57
A_d/%	12.33	3.80
V_d/%	40.59	38.03
FC_d/%	47.08	58.17
M_ar/%	5.06	6.64

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表 2 混煤煤灰与添加剂的元素分析

Table 2 Elemental contents of raw coals ashes, blending coals ash and additives ashes

Composition w/%	High sodium coal ash	Low sodium coal ash	Blending coals ash	Fly ash	Drying ash
SiO₂	6.51	30.05	21.15	5.4	4.09
Al₂O₃	6.09	18.93	13.56	0.97	1.65
Fe₂O₃	4.95	9.91	8.46	0.48	1.48
CaO	31.99	24.16	24.9	58.83	14.86
MgO	12.49	7.07	8.06	2.71	4.87
Na₂O	7.74	0.61	3.45	0.14	0.78
K₂O	0.18	1.41	1.03	0.15	1.14
SO₃	28.11	4.65	18.79	0.79	3.19
P₂O₅	0.10	0.32	0.22	0.06	0.04
CO₂	1.84	2.88	0.38	30.47	67.89

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表 3 各工况主要元素配比

Table 3 Main elemental ratios at different experimental conditions

w/%	Blending coals	Blending coals +2.5% fly ash	Blending coals +5% fly ash	Blending coals +2.5% drying ash	Blending coals +5% drying ash
CaO	24.9	35.44	42.82	26.8	28.39
SiO₂	21.15	18.79	17.13	20.38	19.74
Al₂O₃	13.56	11.42	9.91	12.8	12.16
MgO	8.06	7.33	6.81	8.69	9.22
Na₂O	3.45	2.87	2.47	3.35	3.27
Fe₂O₃	8.46	7.09	6.13	8.11	7.82
Ca/Si	1.18	1.89	2.5	1.32	1.44
Ca/(Si+Al)	0.72	1.17	1.58	0.81	0.89
Ca∶Si∶Al	1.8∶1.6∶1	3.1∶1.6∶1	4.3∶1.7∶1	2.1∶1.6∶1	2.3∶1.6∶1

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