CaO调质污泥自然失水特性及数学模型研究

周俏俏; 葛仕福; 丁晶; 周彩玲

doi:10.12153/j.issn.1674-991X.20210282

CaO调质污泥自然失水特性及数学模型研究

doi: 10.12153/j.issn.1674-991X.20210282

东南大学能源与环境工程学院

基金项目: 国家重点研发计划项目（2020YFC1908700）

详细信息

作者简介:
周俏俏(1996—)，女，硕士研究生，主要从事土壤重金属治理研究，1425280014@qq.com

通讯作者:
葛仕福(1962—)，男，教授，主要从事干燥设备及技术研究，ge1962@126.com

中图分类号: X705
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- 文章访问数: 233
- HTML全文浏览量: 104
- PDF下载量: 13
- 被引次数: 0
出版历程
- 收稿日期: 2021-06-30
- 网络出版日期: 2022-06-07

Study on natural water loss characteristics and mathematical model of CaO conditioned sludge

School of Energy and Environment, Southeast University

摘要

摘要:
以城市污泥为对象，研究CaO添加比、空气流速及污泥堆积厚度对CaO调质污泥自然失水特性的影响。结果表明：污泥失水速率与空气流速、CaO添加比成正比，与堆积厚度成反比。基于Page模型建立的通用模型拟合值与实测值吻合较好，均方根误差为6.34%，能较好地模拟CaO调质污泥自然失水过程。根据Page模型计算出的污泥有效水分扩散系数为9.96×10⁻⁹~1.65×10⁻⁷，自然失水时间与CaO添加比、空气流速呈正相关，与污泥堆积厚度呈负相关。以单位失水量总费用为评价指标，采用MATLAB软件中Fmincon函数计算出单位失水量总费用最低时的最优干燥参数组合：CaO添加比为0.02，空气流速为0.6 m/s，污泥堆积厚度为7 mm。
- 污泥 /
- CaO调质 /
- 自然失水 /
- 数学模型 /
- 参数优化
Abstract:
The effects of CaO addition ratio, airflow rate and bulking thickness on the natural water loss characteristics of municipal sludge treated by CaO were studied. The results showed that sludge water loss rate was proportional to airflow rate and CaO addition ratio, but inversely proportional to bulking thickness. The experimental data were well fitted by the general model based on the Page model with the root mean square error of 6.34%, which could better simulate the natural dewatering process of CaO-treated sludge. The effective water diffusion coefficient of the sludge calculated using the Page model was 9.96×10⁻⁹-1.65×10⁻⁷. The natural water loss time was positively correlated with the CaO addition ratio and airflow rate, and negatively correlated with the bulking thickness. Using the total cost per unit water loss as the evaluation index, the Fmincon function in MATLAB software was applied to calculate the optimal drying parameters under the condition of the lowest total cost per unit water loss. The optimal combination of drying parameters was: CAO addition ratio 0.02, airflow rate 0.6 m/s, sludge accumulation thickness 7 mm.
- sludge /
- CaO conditioning /
- natural water loss /
- mathematical model /
- parameter optimization

HTML全文

图 1 CaO添加比对污泥温度的影响

Figure 1. Effect of CaO addition ratio on sludge temperature

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图 2 CaO添加比对污泥pH的影响

Figure 2. Effect of CaO addition ratio on the pH of sludge

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图 3 CaO添加比对污泥失水特性的影响

Figure 3. Water loss characteristic curve of sludge under different CaO addition ratios

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图 4 空气流速对污泥失水特性的影响

Figure 4. Water loss characteristic curve of sludge under different airflow rates

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图 5 堆积厚度对污泥失水特性的影响

Figure 5. Water loss characteristic curve of sludge under different accumulation thickness

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图 6 水分比实测值和模型预测值的比较

Figure 6. Comparison of experimental and model predicted values of MR

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图 7 不同干燥条件下污泥的有效水分扩散系数

Figure 7. Effective water diffusion coefficient of sludge under different drying conditions

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图 8 不同干燥条件对自然失水时间的影响

Figure 8. Effect of different drying conditions on the natural water loss time

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图 9 单位失水量总费用与CaO添加比、空气流速、堆积厚度的关系

Figure 9. Relationship between the total cost per unit water loss and CaO addition ratio, airflow rate, bulking thickness

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表 1 常用薄层干燥模型及拟合结果

Table 1. Common thin-layer drying models and fitting results

模型编号	模型名称	模型方程	R²均值	χ²均值
1	Newton^[23]	MR=exp(−kt)	0.968 7	2.6×10⁻³
2	Page^[24]	MR=exp(−ktⁿ)	0.994 7	5.7×10⁻⁴
3	Henderson等^[25]	MR=aexp(−kt)	0.962 7	2.7×10⁻³
4	Tow-term^[26]	MR=a₁exp(−k₁t)+a₂exp(−k₂t)	0.983 9	7.0×10⁻⁴
5	Logarithmic^[27]	MR=aexp(−kt)+c	0.979 3	1.2×10⁻³
注：a、c为干燥常数；k、n为模型参数。

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表 2 Page模型统计分析结果

Table 2. Statistical analysis results of Page model

模型方程	CaO添加比	空气流速/(m/s)	堆积厚度/mm	R²	χ²	模型参数
模型方程	CaO添加比	空气流速/(m/s)	堆积厚度/mm	R²	χ²	k	n
MR=exp(−ktⁿ)	0.1	1.8	2	0.989 7	8.9×10⁻⁴	0.041 4	0.763
	0.2	1.8	2	0.992 3	9.8×10⁻⁴	0.048 7	0.784
	0.3	1.8	2	0.995 8	3.7×10⁻⁴	0.057 6	0.803
	0.4	1.8	2	0.997 5	1.9×10⁻⁴	0.073 9	0.834
	0.2	0.6	5	0.996 6	3.4×10⁻⁴	0.017 8	0.755
	0.2	1.2	5	0.999 9	2.8×10⁻⁶	0.018 6	0.766
	0.2	1.8	5	0.996 7	3.9×10⁻⁴	0.023 3	0.777
	0.2	1.8	8	0.998 8	1.5×10⁻⁴	0.014 6	0.765

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