Performance and mechanism of thermochemical technology for oily sludge cleaning

doi:10.16085/j.issn.1000-6613.2021-1376

Abstract

Abstract:

Thermochemical cleaning is a cost-effective method for treating oily sludge. The thermochemical cleaning effect was analyzed systematically, and the mechanism of crude oil desorption was also discussed preliminarily in this study to realize harmless treatment of oily sludge. This study showed that the compound cleaning agent NAS can reduce residual oil rate in solids to 0.94% with cleaning conditions of 4% (concentration), 60℃ (temperature), 8∶1 (liquid-to-solid ratio), and 60min (time), which is far lower than the requirement of oil content ≤2.0% in the "Pollution control requirements for comprehensive utilization of oil and gas field oily sludge" (DB 65/T 3998—2017) and other standards. The results of desorption isotherm model fitting and thermodynamic parameter calculation showed that the desorption of oil from solids surface conforms to the Langmuir model and was a spontaneous endothermic process. Combined with the analysis results of FTIR and XRD, it can be seen that the thermochemical cleaning method mainly removed the light components of crude oil in the oily sludge, and chemical adsorption occurred between solids surface and heavy components, which was the dominant factor affecting the desorption of crude oil.

Key words: oil sludge, thermochemical cleaning, desorption, thermodynamics, simulation

摘要：

热化学清洗法是一种处理含油污泥经济高效的方法。以无害化处理为目标，本文系统分析了热化学清洗含油污泥的效果，并对原油脱附机理进行了初步探讨。结果表明，复配型清洗剂NAS在4%（质量分数）、60℃（温度）、8∶1（液固比）、60min（时间）的清洗条件下，可将固体残油率降低至0.94%，远低于《油气田含油污泥综合利用污染控制要求》（DB 65/T 3998—2017）等多个标准中规定的含油率≤2.0%的要求；脱附等温线模型拟合和热力学参数计算结果表明，油从固体表面的脱附符合Langmuir模型，且为自发吸热过程；结合FTIR及XRD等分析结果可知，热化学清洗法主要除去了含油污泥中原油的轻组分，重组分与固体表面发生化学吸附，成为影响原油脱附的主导因素。

关键词: 含油污泥, 热化学清洗, 脱附, 热力学, 模拟

CLC Number:

X741

WANG Yujing, ZHANG Nan, LIU Shejiang, MIAO Chen, LIU Xiuli. Performance and mechanism of thermochemical technology for oily sludge cleaning[J]. Chemical Industry and Engineering Progress, 2022, 41(6): 3333-3340.

王宇晶, 张楠, 刘涉江, 苗辰, 刘秀丽. 热化学清洗含油污泥的效果评价及机理[J]. 化工进展, 2022, 41(6): 3333-3340.

Figures/Tables 12

References 23

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清洗剂	Na₂SiO₃/%	LAS/%	AEO-7/%	残油率/%	除油率/%
NLA	33.33	33.33	33.33	2.32	86.80
NAS	50.00	50.00	0.00	1.87	89.38
NAE	50.00	0.00	50.00	2.15	87.77
LAE	0.00	50.00	50.00	2.74	84.41
NSE	50.00	40.00	10.00	2.28	87.03
NSO	50.00	30.00	20.00	2.35	86.65

清洗剂	Na₂SiO₃/%	LAS/%	AEO-7/%	残油率/%	除油率/%
NLA	33.33	33.33	33.33	2.32	86.80
NAS	50.00	50.00	0.00	1.87	89.38
NAE	50.00	0.00	50.00	2.15	87.77
LAE	0.00	50.00	50.00	2.74	84.41
NSE	50.00	40.00	10.00	2.28	87.03
NSO	50.00	30.00	20.00	2.35	86.65

序号	因素				残油率 /%
序号	温度/℃	时间/min	液固比	清洗剂质量分数/%	残油率 /%
1	50	40	5∶1	3	4.73
2	50	60	6∶1	4	2.37
3	50	80	8∶1	5	2.13
4	60	40	6∶1	5	1.86
5	60	60	6∶1	3	1.73
6	60	80	5∶1	4	2.82
7	70	40	6∶1	4	1.54
8	70	60	5∶1	5	2.12
9	70	80	6∶1	3	3.60
K₁	3.08	2.71	3.22	3.02
K₂	1.80	1.74	2.61	2.04
K₃	2.42	2.85	1.47	2.24
R	1.27	1.11	0.61	0.98

序号	因素				残油率 /%
序号	温度/℃	时间/min	液固比	清洗剂质量分数/%	残油率 /%
1	50	40	5∶1	3	4.73
2	50	60	6∶1	4	2.37
3	50	80	8∶1	5	2.13
4	60	40	6∶1	5	1.86
5	60	60	6∶1	3	1.73
6	60	80	5∶1	4	2.82
7	70	40	6∶1	4	1.54
8	70	60	5∶1	5	2.12
9	70	80	6∶1	3	3.60
K₁	3.08	2.71	3.22	3.02
K₂	1.80	1.74	2.61	2.04
K₃	2.42	2.85	1.47	2.24
R	1.27	1.11	0.61	0.98

模型	参数	40℃	50℃	60℃
Langmuir	Q₀/mg·g^-1	89.2479	72.2862	54.6426
	K_L/L·g^-1	2.3534	2.9185	3.3579
	R²	0.9988	0.9967	0.9908
Freundlich	K_F	63.1455	50.1569	30.5280
	1/n	0.2221	0.2395	0.2848
	R²	0.9149	0.9208	0.9889
Redlich-Peterson	K_RP	61.4854	48.9305	30.3957
	α	0.1168	0.1288	0.1766
	β	2.0952	1.9972	1.6523
	R²	0.8667	0.8889	0.9295