水溶液全循环法尿素蒸发系统工艺设计及优化毕业论文.doc

ANYANG INSTITUTE OF TECHNOLOGY 本 科 毕 业 论 文 年产20万吨水溶液全循环法尿素蒸发系统工艺设计与优化 The process design and optimization of evaporation system in aqueous solution total recycle which yearly produces two hundred thousand ton urea 年产20万吨水溶液全循环法尿素蒸发系统工艺设计及优化 摘要 水溶液全循环法生产尿素工艺装置，主要包括六个方面：原料的压缩和净化，尿素的合成，中低压解吸收，解吸，蒸发造粒。原料CO2由合成车间净化工段送来，液氨由氨库送来，两种反应物经加压加热送入合成塔反应生成尿素。合成塔出来的合成液中含有尿素、氨基甲酸铵、过剩的氨和水。再经过循环回收进入合成塔，整个过程靠水作为循环介质。由闪蒸槽流出的尿液进入一段蒸发器的加热段加热至130℃，在0.033Mpa压力下，尿素浓度达到96％（W）,进入二段蒸发加热器，加热至140℃，继续减压至0.0033Mpa（绝），尿液浓度提高至99.7％（W），尿液进入熔融泵送往造粒塔，由旋转喷头喷洒造粒。本设计主要通过参考工厂数据进行蒸发阶段的物料及热量衡算，得出蒸发阶段各部分的出入物料及热量，然后进行设备选型及对整个工段进行优化。 关键词：水溶液全循环法 一段蒸发器 物料衡算 热量衡算 The process design and optimization of evaporation system in aqueous solution total recycle which yearly produces two hundred thousand ton urea Abstract Total recycle urea solution production process equipment, including six areas: raw materials, compression and purification, urea synthesis solution in the low absorption, desorption, evaporation and granulation. CO2 from the purification of raw materials, synthetic plant Section sent, liquid ammonia from the ammonia library brought the two reactants into the reactor by the pressure and heat the reaction of urea. Reactor out of the synthesis solution containing urea, ammonium carbamate, excess ammonia and water. Then after recycling into the reactor, the whole process by the water as the circulating medium. Outflow of urine from the flash tank into a heating section of the evaporator heated to 130 ℃, the pressure in the 0.033Mpa urea concentration 96% (W), into the secondary evaporator heater, heated to 140 ℃, to decompression To 0.0033Mpa (absolute), urine concentrations increased to 99.7% (W), the urine into the melt pump sent to the granulation tower, from the rotating nozzle spray granulation. The reference plant design data, primarily through the evaporation stage of materials and heat balance, obtained access to all parts of evaporation stage of materials and e