尿素解吸塔改造总结

尿素解吸塔改造总结章志萍（巨化集团公司合成氨厂浙江衢州，３２４００４）尿素解吸塔是生产尿素过程中，把氨从氨水中解吸出来，返回吸收系统，以达到氨的全部利用，降低尿素氨耗的重要设备。尿素解吸塔的基本要求是：解吸塔底排出废液应不含氨，以减少氨耗；塔顶排出气...     

尿素解吸塔气相出口增设冷却器小结

长期以来,我厂尿素解吸塔出口气相含水一直偏高,当解吸负荷≥8 m~3/h时,解吸气中含水大都高于50％,而含氨仅在30％以下。致使二循一冷器有时排放操作;同时也影响了系统的水平衡。降低了尿素合成反应转化率。造成我厂解吸气相含水高的原因是: 1.解吸塔顶温度高。在将解吸塔底部     

尿素解吸系统改造新工艺

采用碳铵液解吸新工艺和特殊塔内件结构设计,保证塔釜尿素解吸废液中氨含量达到环保要求,同时增产尿素、节省蒸汽。     

CO2汽提法尿素装置解吸废液达标改造小结

山西丰喜华瑞煤化工有限公司1 000 t/d CO₂汽提法尿素装置于2006年7月建成投产,其解吸水解系统解吸废液量约35 m³/h,长期以来,解吸废液中氨含量20～30 mg/L、尿素含量70～80 mg/L,远达不到环保排放要求;将此高氨氮含量的废液补入尿素循环水系统,不利于循环水系统的优质运行。经调研考察与对标分析等,找到了症结所在,2022年8—9月尿素装置停车大修期间实施了加高解吸塔塔体、更换解吸塔与水解塔塔盘、增设卧式水解器及板式换热器等优化改造。改造后,解吸水解系统运行正常,解吸废液氨含量、尿素含量均小于5 mg/L,水解塔(含新增的卧式水解器)中压蒸汽用量大幅减少,助力了尿素装置的优质运行。     

斯塔米卡邦二氧化碳汽提尿素解吸水解的操作

山西兰花科创田悦化肥有限责任公司(简称田悦公司)尿素解吸水解装置采用斯塔米卡邦公司的技术(低压解吸、中压水解),于2007年投入运行。运行3年多来,废液中尿素和氨质量分数均小于10×10-6。由于节能减排和环境保护的要求不断提高,要求废水中氨和尿素质量分数均小于5×10-6,全部送至造气系统进行回收,对尿素解吸水解装置的运行提出了更高的要求。     

尿素解吸塔的优化改造

基于工艺软件包 ,对尿素解吸塔进行了模拟、分析 ,找出了存在的问题。应用流动参数规则和模糊决策方法 ,确定了尿素解吸塔的优化改造方案。改造实施后 ,实现了装置的稳定运行     

尿素装置Φ700解吸塔的技术改造

针对合成氨系统氨水回收至解吸系统工艺中存在的解吸塔超压带液及氨回收率低等问题,进行了原因分析,对尿素装置Φ 700解吸塔进行改造.改造后,解吸能力增强,消除了超压带液现象,氨产量增加.     

尿素解吸塔技改小结

改造前解吸塔简况。改造前，我公司尿素一车间解吸塔共有15块塔板，塔底为直接蒸汽加热，用蒸汽量的大小来控制解吸塔底部温度，保持解吸压力下的水的沸点温度，使塔底排出的废液氨含量尽可能小。通过解吸给料泵将碳铵液从碳液槽送到解吸塔，解吸塔的进料分冷流和热流两路，热流量的大小根据解吸塔的能力与碳液槽的液位高低进行调节，     

巧解水解泵机械密封易损坏的难题

<正>二氧化碳汽提法尿素的解吸系统分为解吸和水解两部分。水解主要是利用尿素和水生成氨和二氧化碳的反应来将氨水槽中的尿素处理掉,从而使解吸废液中的氨含量小于5×10-6。水解泵将来自第一解吸塔的氨水加压输送至水解塔。其进口压力为0.2～0.3MPa,出口压力为1.8～2.0MPa。由于出口压力高、流量大,水解泵大都选用多级离心泵。我公司尿素装置开车后,水解泵机械密封是三天两头坏,有时备用泵还未修复在用泵机封又     

尿素装置“六改十”塔器改造技术

该文介绍了与尿素装置“六改十”配套的尿塔、一吸塔、解吸塔等塔器的改造原理、技术及改造效果。     

Preparation and characterization of chitosan/Cu(II) affinity membrane for urea adsorption

We used silica particles as a porogen to prepare macroporous chitosan membranes and subsequently prepared macroporous chitosan/Cu(II) affinity membranes for urea adsorption. The morphology, porosity, Cu(II) adsorption capacity, and swelling ratio of the macroporous membrane were measured. SEM photographs show the pores in the membrane dispersed uniformly, a feature that didn't change much after the adsorption of Cu(II). The porosity of the membrane had a maximum value when the silica/chitosan ratio was about 12. The Cu(II) adsorption capacity in the membrane leveled off when the initial concentration of CuSO₄ solution exceeded 5 × 10^?2 mol/L. The macroporous chitosan/Cu(II) affinity membrane was successfully used for urea adsorption. The maximum urea adsorption capacity was 78.8 mg/g membrane, which indicates that the membrane has a great potential for hemodialysis for urea removal. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1108–1112, 2003     

木质素磺酸钠在TiO2/水界面的吸附特性

木质素磺酸钠在固体表面的吸附特性决定了其应用性能,利用红外和紫外分光光度仪,采用剩余质量分数法研究了温度、pH值、无机盐和氢键破坏剂脲对木质素磺酸钠在TiO₂/水界面吸附动力学和等温吸附性能的影响,初步探讨了其在固液界面的吸附作用机理。结果表明,该吸附为单层多点式吸附,随着温度升高和pH值减小,木质素磺酸钠在TiO₂/水界面的吸附速率常数和饱和吸附量均增大,而离子强度的增大和脲的加入却使吸附速率常数减小;木质素磺酸钠在TiO₂/水界面的吸附驱动力为静电、疏水和氢键作用,疏水作用力可显著增加其吸附量。     

Adsorption of urea,creatinine, and uric acid from three solution types using spherical activated carbon and its recyclability

In this paper, we propose that the urinary toxins from the wastewater be adsorbed on an adsorbent such as spherical activated carbon and the latter be regenerated by subjecting it to high temperatures to recycle activated carbon and also to recycle the water used in dialysis. We studied the adsorption of artificial waste dialysate, which is a mixed solution of urea, creatinine, and uric acid, and the separate solutions for each of these and found that their extents of adsorption onto the spherical activated carbon material were nearly identical. The amount of adsorption was approximately 1.4 mg·g^-1 for urea, 18 mg·g^-1 for creatinine, and 20 mg·g^-1 for uric acid. The urea, creatinine, and uric acid adsorbed onto the spherical activated carbon decomposed on heat treatment at 500℃, and the adsorption capacity of the spherical activated carbon was regenerated. Our study successfully demonstrated that the spherical activated carbon can be recycled in the waste dialysate treatment process.     

木质素磺酸钠在活性炭/水界面的吸附机理

为了探究木质素磺酸钠在活性炭/水界面的吸附机理,研究了温度、pH 值、无机盐、脲以及直链醇对其吸附动力学及吸附等温线的影响.吸附动力学结果表明,木质素磺酸钠在活性炭/水界面的吸附约在10 min 内快速达到平衡;随着离子强度的增加及脲的加入吸附速率常数增大,pH值增加,吸附速率常数先增大后减小.不同pH值条件下的木质素磺酸钠在活性炭/水界面的吸附等温线符合 Langmuir 方程;随着离子强度增大、脲或直链醇的加入,吸附过程更符合 Freundlich 模型.增加离子强度、降低 pH 值及加入直链醇都可显著提高木质素磺酸钠的平衡吸附量,而脲的加入降低平衡吸附量.在中性条件下木质素磺酸钠主要通过疏水作用和氢键作用吸附在活性炭/水界面,疏水作用有利于加快吸附速率及增加吸附量,该吸附过程不受温度的影响.     

Adsorption of urea,creatinine, and uric acid from three solution types using spherical activated carbon and its recyclability

In this paper, we propose that the urinary toxins from the wastewater be adsorbed on an adsorbent such as spherical activated carbon and the latter be regenerated by subjecting it to high temperatures to recycle activated carbon and also to recycle the water used in dialysis. We studied the adsorption of artificial waste dialysate, which is a mixed solution of urea, creatinine, and uric acid, and the separate solutions for each of these and found that their extents of adsorption onto the spherical activated carbon material were nearly identical. The amount of adsorption was approximately 1.4 mg·g⁻¹ for urea, 18 mg·g⁻¹ for creatinine, and 20 mg·g⁻¹ for uric acid. The urea, creatinine, and uric acid adsorbed onto the spherical activated carbon decomposed on heat treatment at 500 °C, and the adsorption capacity of the spherical activated carbon was regenerated. Our study successfully demonstrated that the spherical activated carbon can be recycled in the waste dialysate treatment process.     

Effect of molecular weight and degree of deacetylation of chitosan on urea adsorption properties of copper chitosan

Copper chitosan complexes prepared by different specifications of chitosan and copper sulfate were used as urea sorbents. Experimental results showed that the adsorption capacity for urea of copper chitosan increased with an increasing degree of deacetylation and decreasing molecular weight of chitosan. The urea adsorption capacity of copper chitosan was 120.0 mg/g, when 1.0 g of copper chitosan was admitted to 100 mL of a 1300 mg/mL (pH 6.0) urea solution, with chitosan degree of deacetylation of 84.3% and viscosity molecular weight of 6.5 × 10⁵, at 37°C for 8 h. No elution of the copper from the copper chitosan could be detected under the optimal conditions. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 1520–1523, 2003     

A high-performance biochar produced from bamboo pyrolysis with in-situ nitrogen doping and activation for adsorption of phenol and methylene blue

Nitrogen doping is a promising method for the preparation of functional carbon materials. In this study, a nitrogen-doped porous coral biochar was prepared by using bamboo as raw material, urea as nitrogen source, and KHCO³ as green activator through in-situ pyrolysis. The structure of the obtained biochar was characterized by various techniques including nitrogen adsorption and desorption, Raman spectroscopy, X-ray photoelectron spectrometer, and etc. The adsorption properties of nitrogen-doped biochar were evaluated with phenol and methylene blue probes. The results showed that the nitrogen source ratio had a significant effect on the evolution of pore structure of biochar. Low urea addition ratio was beneficial to the development of pore structures. The optimum specific surface area of nitrogen-doped biochar could be up to 1693 m²·g^-1. Nitrogen doping can effectively improve the adsorption capacity of biochar to phenol and methylene blue. Biochar prepared at 973.15 K with low urea addition ratio exhibited the highest adsorption capacity for phenol and methylene blue, and the equilibrium adsorption capacity was 169.0 mg·g^-1 and 499.3 mg·g^-1, respectively. By comparing the adsorption capacity of various adsorbents in related fields, it is proved that the nitrogen-doped biochar prepared in this study has a good adsorption effect.     

A high-performance biochar produced from bamboo pyrolysis with in-situ nitrogen doping and activation for adsorption of phenol and methylene blue

Nitrogen doping is a promising method for the preparation of functional carbon materials. In this study, a nitrogen-doped porous coral biochar was prepared by using bamboo as raw material, urea as nitrogen source, and KHCO₃ as green activator through in-situ pyrolysis. The structure of the obtained biochar was characterized by various techniques including nitrogen adsorption and desorption, Raman spectroscopy, X-ray photoelectron spectrometer, and etc. The adsorption properties of nitrogen-doped biochar were evaluated with phenol and methylene blue probes. The results showed that the nitrogen source ratio had a significant effect on the evolution of pore structure of biochar. Low urea addition ratio was beneficial to the development of pore structures. The optimum specific surface area of nitrogen-doped biochar could be up to 1693 m²·g⁻¹. Nitrogen doping can effectively improve the adsorption capacity of biochar to phenol and methylene blue. Biochar prepared at 973.15 K with low urea addition ratio exhibited the highest adsorption capacity for phenol and methylene blue, and the equilibrium adsorption capacity was 169.0 mg·g⁻¹ and 499.3 mg·g⁻¹, respectively. By comparing the adsorption capacity of various adsorbents in related fields, it is proved that the nitrogen-doped biochar prepared in this study has a good adsorption effect.     

Montmorillonite adsorbs urea and accelerates urea excretion from the intestine

Hyperuraemia is one of the causes of uremia and renal failure. Decreasing serum urea level is an effective therapeutic method for patients with uremia and renal failure. Montmorillonite has very high affinity to various natural or synthetic toxins and has been widely used in biomedicine and clinical therapy. However, its effects on urea adsorption and excretion have not been fully explored. In the present studies, we systematically investigated the effects of montmorillonite on urea adsorption and excretion from the intestine. In vitro studies showed that montmorillonite concentration- and time-dependently adsorbed urea with high affinity. In vivo infusing urea into the blood vessel increased the urea concentration in the intestine, indicating that urea diffused from the blood vessels to the intestine. Infusing urea into the intestine increased the urea concentration in blood indicating that urea was absorbed in the intestine. Administrating montmorillonite in rat intestine significantly increased urea diffusion from the blood to the intestine and decreased urea absorption in the intestine. Orally administrating montmorillonite in normal mice as well as two types of model mice with acute hyperuraemia induced by orally administrating or intraperitoneally injecting urea, respectively, decreased blood urea levels. Our studies demonstrated that administrating montmorillonite has therapeutic potentials in patients with uremia.     

沉淀聚合法合成尿素分子印迹聚合物及其表征

分子印迹聚合物由于具有与天然抗体相似的识别性能和与高分子同样的抗腐蚀性能的双重优点,因而被广泛应用于生物工程、临床医学、环境监测、食品工业等众多领域的研究中[16].合成了尿素分子印迹聚合物(尿素MIP),研究了尿素分子印迹聚合物对尿素的吸附能力,探讨了不同介质对吸附的影响.尿素分子印迹聚合物在乙腈中对尿素分子的识别能...