尿基复合肥包涂造粒过程工业性试验研究
摘要
尿素是我国目前用量最大的化肥，但近年来，随着我国农业的迅速发展，现代农业要求从单一品种的化肥向复合肥发展。世界肥料发展史表明，复合肥的发展已成为化肥工业的重要内容，以至复合肥的生产技术及其占化肥总量的比例已能反映一个国家化肥工业发达程度和科学施肥的水平，而尿基复合肥作为高浓度的化肥，具有相当的优势，在发展高浓度复合肥的大趋势下，国内外纷纷投入力量，加强对尿基复合肥生产工艺、规模的研究和开发，特别是流化造粒工艺。
本文是在小试实验完成磷酸一铵——尿素体系尿基复合肥开发的基础上，利用TEC日产2000吨尿素大颗粒造粒装置，做适当改造，进行尿基复合肥工业化放大试验。试验分两个阶段进行，第一阶段闭路循环主要是考察造粒方式由间歇式改为连续式生产后，造粒机的热量平衡、包裹后产品的外观情况、床层的流态化状况，对获得的产品粒子进行分析，以取得晶种包裹厚度、粒径分布、物性变化等数据。第二阶段开路循环连续性生产试验，针对第一阶试验存在的问题，采取相应的对策，修改控制参数，改进工艺流程，对造粒机生产的尿基复合肥粒子进行筛分等后序处理，以获得具有良好粒径分布的成品粒子，氮、磷两种养分比例的控制，同时未长大的小颗粒和连续外加的晶种一起返回造粒机循环造粒，从而使试验得以实现工业化连续性生产。
试验表明以磷酸一铵为晶种进行尿基复合肥的工业化生产是可行的；造粒过程最适宜的流化床温度应控制在50～60℃之间；选用孔径为2.5mm的压力式喷嘴；流化气速控制在3m／s左右；筛网孔径选择在3mm(下层)～5mm(上层)左右；采用长窄流化床，喷嘴按正三角形分布；晶种粒径分布尽量窄；晶
四川大学工程硕士专业学位论文
种粉尘含量尽可能少，以利于循环洗涤液的处理;按不同的物料配比，可获得
要求的养分比。
The usage of urea is still the largest among fertilizers in China. But recent years, as the rapid development of Chinese modern agriculture, the consumption of fertilizers have changed from single nutrient fertilizer trend to compound fertilizers. According to the progress of the world fertilizer, compound fertilizers have played more and more important roles in fertilizer industry. The production technologies of compound fertilizers and the consumptions have become one of the indicators of a country's fertilizer industry development condition and applying principle level. So, fertilizer manufacturers devoted their techniques and money to produce compound fertilizers, Special for urea-based compound fertilizers production due to its high concentrate nutrients. The topics of the investigations focused on process and scale of plant, especially on fluidization granulation process of urea-based compound fertilizers.
This paper industrial experimented on novel process of granulation of urea-based compound fertilizer with a 2000kt/d TEC granulation unit which by revamped based on the pilot study of granulation of urea-MAP compound fertilizer. The experiments include two stages. In the first stage of closed circuit, the heat balance of granulator, the shape of granulated product and the status of fluidized
bed were tested when operation style changes from batch to continuous. Certain data were determined like the depth of coating layer, the distribution of the diameter of articles and the changes of the physical properties of product and so on by being analyzed the granulated product. In the second stage of open circuit, the alternatives were made to match the demands of the continuous process, such as the alternative of the control indicator, the innovations of the process, the filtration of the articles and other back treatments. After the treatments, good diameter contributions of articles were obtained, and the N: P2O5 ratio can be adjustable. No grown up articles and additional added articles were returned back to granulator recycled to make continuous process of experiments.
The experiments result shown that industrial produce of urea-based compound fertilizer by using MAP as the granulation core is feasible. The most suitable temperature of fluidized bed should be controlled between 50 and 60 . Pressure nozzle should be selected with aperture of 2.5mm. The fluidizing air flow rate should be controlled about 3m/s. The pole of sieve should be chosen as about 3mm of under layer and 5mm of super layer. The fluidized bed should be chosen as rectangular type, the nozzle should be lay out with in a triangle; the diameter distribution of core should be chosen as narrow as possible to decrease the dust, which needed to deal with by circulating washing solution; The N: P2O5 ratio of the nutrients can be adjusted by adjusting the materials.
本文是在小试实验完成磷酸一铵——尿素体系尿基复合肥开发的基础上，利用TEC日产2000吨尿素大颗粒造粒装置，做适当改造，进行尿基复合肥工业化放大试验。试验分两个阶段进行，第一阶段闭路循环主要是考察造粒方式由间歇式改为连续式生产后，造粒机的热量平衡、包裹后产品的外观情况、床层的流态化状况，对获得的产品粒子进行分析，以取得晶种包裹厚度、粒径分布、物性变化等数据。第二阶段开路循环连续性生产试验，针对第一阶试验存在的问题，采取相应的对策，修改控制参数，改进工艺流程，对造粒机生产的尿基复合肥粒子进行筛分等后序处理，以获得具有良好粒径分布的成品粒子，氮、磷两种养分比例的控制，同时未长大的小颗粒和连续外加的晶种一起返回造粒机循环造粒，从而使试验得以实现工业化连续性生产。
试验表明以磷酸一铵为晶种进行尿基复合肥的工业化生产是可行的；造粒过程最适宜的流化床温度应控制在50～60℃之间；选用孔径为2.5mm的压力式喷嘴；流化气速控制在3m／s左右；筛网孔径选择在3mm(下层)～5mm(上层)左右；采用长窄流化床，喷嘴按正三角形分布；晶种粒径分布尽量窄；晶
四川大学工程硕士专业学位论文
种粉尘含量尽可能少，以利于循环洗涤液的处理;按不同的物料配比，可获得
要求的养分比。
The usage of urea is still the largest among fertilizers in China. But recent years, as the rapid development of Chinese modern agriculture, the consumption of fertilizers have changed from single nutrient fertilizer trend to compound fertilizers. According to the progress of the world fertilizer, compound fertilizers have played more and more important roles in fertilizer industry. The production technologies of compound fertilizers and the consumptions have become one of the indicators of a country's fertilizer industry development condition and applying principle level. So, fertilizer manufacturers devoted their techniques and money to produce compound fertilizers, Special for urea-based compound fertilizers production due to its high concentrate nutrients. The topics of the investigations focused on process and scale of plant, especially on fluidization granulation process of urea-based compound fertilizers.
This paper industrial experimented on novel process of granulation of urea-based compound fertilizer with a 2000kt/d TEC granulation unit which by revamped based on the pilot study of granulation of urea-MAP compound fertilizer. The experiments include two stages. In the first stage of closed circuit, the heat balance of granulator, the shape of granulated product and the status of fluidized
bed were tested when operation style changes from batch to continuous. Certain data were determined like the depth of coating layer, the distribution of the diameter of articles and the changes of the physical properties of product and so on by being analyzed the granulated product. In the second stage of open circuit, the alternatives were made to match the demands of the continuous process, such as the alternative of the control indicator, the innovations of the process, the filtration of the articles and other back treatments. After the treatments, good diameter contributions of articles were obtained, and the N: P2O5 ratio can be adjustable. No grown up articles and additional added articles were returned back to granulator recycled to make continuous process of experiments.
The experiments result shown that industrial produce of urea-based compound fertilizer by using MAP as the granulation core is feasible. The most suitable temperature of fluidized bed should be controlled between 50 and 60 . Pressure nozzle should be selected with aperture of 2.5mm. The fluidizing air flow rate should be controlled about 3m/s. The pole of sieve should be chosen as about 3mm of under layer and 5mm of super layer. The fluidized bed should be chosen as rectangular type, the nozzle should be lay out with in a triangle; the diameter distribution of core should be chosen as narrow as possible to decrease the dust, which needed to deal with by circulating washing solution; The N: P2O5 ratio of the nutrients can be adjusted by adjusting the materials.
引文
[1] 李生秀．植物营养与肥料学科的现状与发展．植物营养与肥料科学[J]，1993(3)．
[2] 方天翰主编．复混肥料生产技术手册[M]．北京：化学工业出版社，2003年2月第一版．
[3] 四川省农业科学院水稻高梁研究所．尿基复合肥农试报告(内部资料)．
[4] 茅启昌，周寅仪等．与Hydro就流化床造粒技术交流情况综述．大氮肥[J]，1985(5)．
[5] Mark.Modem Agriculture and Fertilizers.Special Publication[J] No4. 1994.
[6] 余国琮主编．化学机械工程手册[M](上卷)．北京：化学工业出版社，2003年1月第1版．
[7] 潘永康主编．现代干燥技术[M]．北京：化学工业出版社，1997．
[8] U．S．Pat．4，292，067．
[9] U．S．Pat．4，237，8 14．
[10] J．F．戴维森．流态化[M]．北京：化学工业出版社，1981．
[11] U．S．Pat．4，500，336．
[12] WO9954267．
[13] 化学工程编辑委员会．化学工程手册[M](第5卷)．北京：化学工业出版社，1989年 第1版．
[14] 泸天化(集团)有限责任公司尿素装置引进技术、治理污染、改善环境技术改造项目可行性研究报告(档案号：9909-22)．中国五环化学工程公司，1999年3月．
[15] 联合国工业发展组织编．化肥手册[M]．北京：中国对外翻译出版公司出版，1984年第1版．
[16] Pipe Reactor Route Urea Based NP/NPK Process[M]. Hydro Fertilizer Technology.
[17] Chemistry and Technologyof Agrochemical Formulations.edited by D .Knowles.Kluwer Academic[J] Publishers. 1998.
[18] F．T．尼尔逊编．肥料加工手册[M]．北京：化学工业出版社，1992年第1版．
[19] 上海化工研究院编．复合肥生产技术与设备[M]．北京：化学工业出版社，1999年第1版．
[20] 尿基复肥工艺的研究与实践．中国化工报，2000年4月5日．
[21] 王长山．尿基复肥技术交流推广会议资料，2000年4月10日．
[22] CNI. 158, 831.
[23] TEC编．日产2000吨大颗粒装置操作手册[M]．2000．
[24] 化学工程编辑委员会．化学工程手册[M](第2卷)．北京：化学工业出版社，1996年 第2版．
[25] 张洪沅主编．化工原理[M]．成都科技大学出版社，1987．
[26] 宋航，付超．化工技术经济[M]．成都科技大学出版社，1997年4月第1版．
[2] 方天翰主编．复混肥料生产技术手册[M]．北京：化学工业出版社，2003年2月第一版．
[3] 四川省农业科学院水稻高梁研究所．尿基复合肥农试报告(内部资料)．
[4] 茅启昌，周寅仪等．与Hydro就流化床造粒技术交流情况综述．大氮肥[J]，1985(5)．
[5] Mark.Modem Agriculture and Fertilizers.Special Publication[J] No4. 1994.
[6] 余国琮主编．化学机械工程手册[M](上卷)．北京：化学工业出版社，2003年1月第1版．
[7] 潘永康主编．现代干燥技术[M]．北京：化学工业出版社，1997．
[8] U．S．Pat．4，292，067．
[9] U．S．Pat．4，237，8 14．
[10] J．F．戴维森．流态化[M]．北京：化学工业出版社，1981．
[11] U．S．Pat．4，500，336．
[12] WO9954267．
[13] 化学工程编辑委员会．化学工程手册[M](第5卷)．北京：化学工业出版社，1989年 第1版．
[14] 泸天化(集团)有限责任公司尿素装置引进技术、治理污染、改善环境技术改造项目可行性研究报告(档案号：9909-22)．中国五环化学工程公司，1999年3月．
[15] 联合国工业发展组织编．化肥手册[M]．北京：中国对外翻译出版公司出版，1984年第1版．
[16] Pipe Reactor Route Urea Based NP/NPK Process[M]. Hydro Fertilizer Technology.
[17] Chemistry and Technologyof Agrochemical Formulations.edited by D .Knowles.Kluwer Academic[J] Publishers. 1998.
[18] F．T．尼尔逊编．肥料加工手册[M]．北京：化学工业出版社，1992年第1版．
[19] 上海化工研究院编．复合肥生产技术与设备[M]．北京：化学工业出版社，1999年第1版．
[20] 尿基复肥工艺的研究与实践．中国化工报，2000年4月5日．
[21] 王长山．尿基复肥技术交流推广会议资料，2000年4月10日．
[22] CNI. 158, 831.
[23] TEC编．日产2000吨大颗粒装置操作手册[M]．2000．
[24] 化学工程编辑委员会．化学工程手册[M](第2卷)．北京：化学工业出版社，1996年 第2版．
[25] 张洪沅主编．化工原理[M]．成都科技大学出版社，1987．
[26] 宋航，付超．化工技术经济[M]．成都科技大学出版社，1997年4月第1版．
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