pH optimization and control in iron removal process of multi-reactor cascade

doi:10.11949/j.issn.0438-1157.20171393

Abstract

Abstract:

It is difficult to optimize and control pH in iron removal process, due to multi-reactor cascade, delayed detection of ionic concentration, and frequent change of working conditions. A pH optimization control method was proposed for iron removal process of a multi-reactor cascade. This method set pH in each reactor of the cascade according to classification of inlet conditions and amount of oxygen change. Two key factors, i.e. pH and ferrous ion concentration, were used to establish calcine consumption model by chemical reaction mechanism and process material balance. Considered effects of both complex mechanism and delayed detection of ion concentration on accurate addition of calcine, oxidation-reduction potential (ORP) was introduced and combined with pH to build a modified fuzzy model of calcine consumption. Simulation results show effectiveness of the method, which creates foundation for stable operation of amphibolite iron removal process.

Key words: iron removal process, calcine, ORP, pH setpoint, fuzzy rule, process systems, optimization, control

摘要：

针对沉铁过程多反应器级联、离子浓度检测滞后及工况变化频繁导致pH优化控制困难的问题，提出了一种基于多反应器级联的沉铁过程pH优化控制方法。该方法基于入口工况划分与氧气变化量预设定各个级联反应器的pH，并针对影响焙砂添加量的两个主要因素：pH和亚铁离子浓度，建立了基于沉铁过程化学反应机理和物料平衡的焙砂添加量模型；考虑到沉铁过程机理复杂及离子浓度检测滞后影响焙砂的准确添加，引入了氧化还原电位（oxidation-reduction potential，ORP），并提出一种基于ORP和pH变化量的焙砂模糊修正模型。仿真结果证明了该方法的有效性，为针铁矿法沉铁过程的稳定运行创造了条件。

关键词: 沉铁过程, 焙砂, ORP, pH设定值, 模糊规则, 过程系统, 优化, 控制

CLC Number:

TF355.4

LI Yonggang, MA Lei, WU Tiebin, ZHU Hongqiu, YANG Chunhua. pH optimization and control in iron removal process of multi-reactor cascade[J]. CIESC Journal, 2018, 69(6): 2586-2593.

李勇刚, 马蕾, 伍铁斌, 朱红求, 阳春华. 多反应器级联的沉铁过程pH优化控制[J]. 化工学报, 2018, 69(6): 2586-2593.

References 30

[1]	徐采栋. 锌冶金物理化学[M]. 上海:上海科学技术出版社, 1979:237. XU C D. Metallurgical Physicochemistry of Zinc[M]. Shanghai:Shanghai Scientific & Technical Publishers, 1979:237.
[2]	LOAN M, NEWMAN O M G, COOPER R M G, et al. Defining the Paragoethite process for iron removal in zinc hydrometallurgy[J]. Hydrometallurgy, 2006,81(2):104-129.
[3]	CLAASSEN J O, SANDENBERGH R F. Influence of temperature and pH on the quality of metastable iron phases produced in zinc-rich solutions[J]. Hydrometallurgy, 2007, 86(3/4):178-190.
[4]	CARRASCO J, BANOS A, ARENAS A. Reset control of an industrial in-line pH process[J]. IEEE Transactions on Control Systems Technology, 2012,20(4):1100-1106.
[5]	ALDHAIFALLAH M, ALSABBAH S, MUJTABA I. A predictive neural network-based cascade control for pH reactors[J]. Hindawi Publishing Corporation, 2016, (4):5638632-5638639.
[6]	PAWLOWSKI A, MENDOZA J L, GUZMAN J L, et al. Selective pH and dissolved oxygen control strategy for a raceway reactor within an event-based approach[J]. Control Engineering Practice, 2015, 44(22):209-218.
[7]	HERMANSSON A W, SYAFⅡE S. Model predictive control of pH neutralization processes:a review[J]. Control Engineering Practice, 2015, 45(18):98-109.
[8]	LAMICHHANE K M, LEWIS K, RONG K, et al. Treatment of high strength acidic wastewater using passive pH control[J]. Journal of Water Process Engineering, 2017, 18(2):198-201.
[9]	MOON C, JANG S, YUN Y M, et al. Effect of the accuracy of pH control on hydrogen fermentation[J]. Bioresource Technology, 2015, 179(8):595-601.
[10]	IVANOV V K, BARANCHIKOV A Y, KOPITSA G P, et al. pH control of the structure, composition, and catalytic activity of sulfated zirconia[J]. Journal of Solid State Chemistry, 2013, 198(2):496-505.
[11]	GUO S S, DONG Z. Application of DMC algorithm on pH control of WFGD system[J]. Applied Mechanics & Materials, 2014, 568(570):1090-1094.
[12]	唐朝晖, 刘金平, 陈青, 等. 基于预测模型的浮选过程pH值控制[J]. 控制理论与应用, 2013, 30(7):885-890. TANG Z H, LIU J P, CHEN Q, et al. pH control in flotation process based on prediction model[J]. Control Theory & Applications, 2013, 30(7):885-890.
[13]	ZOU Z, MENG Y U, WANG Z, et al. Nonlinear model algorithmic control of a pH neutralization process[J]. Chinese Journal of Chemical Engineering, 2013, 21(4):395-400.
[14]	李勇刚, 杨根, 阳春华. 基于参数自整定模糊控制器的沉铁过程pH值稳定控制[J]. 化工学报, 2013, 64(12):4557-4562. LI Y G, YANG G, YANG C H. pH control in iron precipitation process based on parameter self-tuning fuzzy controller[J]. CIESC Journal, 2013, 64(12):4557-4562.
[15]	YU R F, CHEN H W, CHENG W P, et al. Monitoring of ORP, pH and DO in heterogeneous Fenton oxidation using nZVI as a catalyst for the treatment of azo-dye textile wastewater[J]. Journal of the Taiwan Institute of Chemical Engineers, 2014, 45(3):947-954.
[16]	冯华良, 高教琪, 侯胜博, 等. ORP调控对马克斯克鲁维酵母发酵纤维素水解液的影响[J]. 化工学报, 2017,68(11):4279-4287. FENG H L, GAO J Q, HOU S B, et al. Effect of ORP regulation on fermentation by Kluyveromyces marxianus from lignocellulosic hydrolysates[J]. CIESC Journal, 2017, 68(11):4279-4287.
[17]	RUANO M V, RIBES J, SECO A, et al. An advanced control strategy for biological nutrient removal in continuous systems based on pH and ORP sensors[J]. Chemical Engineering Journal, 2012, 183(4):212-221.
[18]	SUN B, GUI W H, WU T B, et al. An integrated prediction model of cobalt ion concentration based on oxidation-reduction potential[J]. Hydrometallurgy, 2013, 140(11):102-110.
[19]	HU Z, CHAN C W. In-situ bioremediation for petroleum contamination:a fuzzy rule-based model predictive control system[J]. Engineering Applications of Artificial Intelligence, 2015,38(2):70-78.
[20]	乔峥, 刘颖, 赵珺,等. 基于子集融合与规则简约的磨矿过程模糊建模[J]. 控制理论与应用, 2015,32(6):770-777. QIAO Z, LIU Y, ZHAO J, et al. Grinding process modeling based on fuzzy sets merging and rule simplification[J]. Control Theory & Application, 2015, 32(6):770-777.
[21]	LI T, XU G, FANG L, et al. Double-fuzzification fuzzy control and its application in process control[C]//EMEIT. 2011 International Conference on Electronic and Mechanical Engineering and Information Technology. Harbin, Heilongjiang, China:IEEE, 2011:1527-1529.
[22]	DEMIRCI Y, PEKEL L C, ALTINTEN A, et al. Application of fuzzy control on the electrocoagulation process to treat textile wastewater[J]. Environmental Technology, 2015,36(24):3243-3252.
[23]	QIAO J, ZHANG W, HAN H. Self-organizing fuzzy control for dissolved oxygen concentration using fuzzy neural network1[J]. Journal of Intelligent & Fuzzy Systems, 2016, 30(6):3411-3422.
[24]	彭亚为, 陈娟, 刘占富, 等. 自适应模糊滑模控制在化工过程中的应用[J]. 化工学报, 2012, 63(9):2843-2850. PENG Y W, CHEN J, LIU Z F, et al. Adaptive fuzzy sliding mode control in chemical process application[J]. CIESC Journal, 2012, 63(9):2843-2850.
[25]	AL-JEHANI A N, NOUNOU H N, NOUNOU M N. Fuzzy control of a CSTR process[C]//ISMA. 20128th International Symposium on Mechatronics and ITS Applications. Sharjah, United Arab Emirates:IEEE, 2012:1-6.
[26]	SHAHRAZ A, BOOZARJOMEHRY R B. A fuzzy sliding mode control approach for nonlinear chemical processes[J]. Control Engineering Practice, 2009,17(5):541-550.
[27]	DEMIRCI Y, PEKEL L C, ALTINTEN A, et al. Improvement of the performance of an electrocoagulation process system using fuzzy control of pH[J]. Water Environment Research, 2015, 87(12):2045.
[28]	CHUNG C C, CHEN H H, TING C H. Grey prediction fuzzy control for pH processes in the food industry[J]. Journal of Food Engineering, 2010, 96(4):575-582.
[29]	熊富强. 锌浸出针铁矿法沉铁过程的建模研究及应用[D]. 长沙:中南大学, 2012. XIONG F Q. Modeling of iron precipitation by goethite process in zinc leaching and its application[D]. Changsha:Central South University, 2012
[30]	王丹丽, 董晓丹. 针铁矿对重金属离子的吸附作用[J]. 黄金, 2002, 23(2):44-46. WANG D L, DONG X D. Adsorption of heavy metal ions on goethite[J]. Gold, 2002, 23(2):44-46.