2012年我国尿素工业装置及产量、消耗情况

2012年,我国共有尿素生产企业170家,尿素生产装置262套,尿素产量61926kt。大型CO2汽提工艺尿素装置吨尿素氨耗568—575kg、电耗18～70kW·h、蒸汽消耗1100～1467kg,中、小型CO2汽提工艺尿素装置吨尿素氨耗570～590kg、电耗105～180kW·h、蒸汽消耗882～1449kg;大型氨汽提工艺尿素装置吨尿素氨耗578～584kg、电耗33～195kW·h、蒸汽消耗1110—1245kg,中、小型氨汽提工艺尿素装置吨尿素氨耗568～605kg、电耗125～183kW·h、蒸汽消耗968～1169kg;水溶液循环工艺尿素装置吨尿素氨耗570～600kg、电耗145—200kW·h、蒸汽消耗1069—1810kg。     

尿素装置蒸汽消耗控制探讨

大型尿素生产装置中,所用蒸汽除满足工艺换热要求外,还用于驱动二氧化碳压缩机汽轮机,蒸汽用量较大,对尿素成本的影响不容小觑。本文以二氧化碳汽提法尿素装置为例,探讨控制蒸汽消耗的措施。     

蒸汽系统优化控制措施探讨

提高尿素装置的利用率,节能降耗是关键。通过对蒸汽系统进行优化调整,保证了尿素装置在低负荷工况下,蒸汽消耗的明显降低。     

改进型全循环法尿素装置设计运行总结

介绍了700 t/d改进型全循环法尿素装置的生产运行效果.从CO2转化率、蒸汽消耗、一吸系统热平衡等方面分析了该尿素装置的生产运行数据,并与CO2汽提法尿素工艺、UTI尿素工艺以及传统全循环法尿素工艺进行了对比.结果表明,改进型全循环法尿素装置吨尿素蒸汽消耗仅为985 kg,比传统全循环法尿素装置降低蒸气消耗610 k...     

CO2汽提法尿素装置降低消耗的新举措

中海石油华鹤煤化有限公司520kt/aCO2汽提法尿素装置采用斯塔米卡邦2000+TM工艺,装置投运以来总体运行平稳.2015—2019年的生产统计数据表明,吨尿素蒸汽消耗和循环水消耗超过设计值.分析认为症结在于,尿素装置长时间运行在105％～108％负荷下,因池式反应器低压侧副产蒸汽量无法满足低压蒸汽用户(主要是蒸发...     

CO2汽提法尿素装置解吸废液减排技改小结

安徽六国化工股份有限公司300 kt/a CO₂汽提法尿素装置每生产1 t尿素产生约0.60 t的氨水,需在解吸水解系统中处理成NH₃含量<5×10^-6、尿素含量<5×10^-6的合格废液排出。传统尿素装置氨水处理采用外来加热蒸汽直接加入解吸塔底部的方法,加热蒸汽冷凝液与解吸废液混合在一起造成解吸废液排放量大、蒸汽冷凝液难以回收利用等弊端。为此,六国化工对尿素解吸水解系统进行了解吸废液减排技改——在第二解吸塔底部外置蒸汽发生器,部分解吸废液经蒸汽发生器壳侧中压蒸汽间接加热产生二次蒸汽以加热第二解吸塔塔底解吸废液,中压蒸汽冷凝液则回收至蒸汽冷凝液系统循环利用,由此实现了降低解吸废液排放量、减轻企业环保压力、无污染高品质蒸汽冷凝液回收利用的目标,有力地推动了尿素装置的节能减排。     

“汽”改“水”抽真空技术在尿素蒸发系统的应用

<正>吉林通化化工股份有限公司(以下简称通化公司)合成氨装置生产能力为100 kt/a、尿素装置生产能力为130 kt/a。原蒸发系统采用蒸汽喷射抽真空的方式,吨尿素抽真空耗蒸汽68 kg,吨尿素总蒸汽消耗1 380 kg、总氨耗578 kg。为解决原有蒸汽喷射抽真空方式蒸汽消耗高的状况,同时解决蒸汽喷射器因蒸汽压力的波动不易操作等问题,通化公司经充分考察论证后,于2009年     

斯那姆氨汽提尿素装置蒸汽冷凝液系统改造

尿素装置和三聚氰胺系统联运后,三聚氰胺返回尿素的工艺碳铵液造成尿素系统水碳比增高,尿素转化率下降,中、低压系统负荷增加,蒸汽冷凝液系统超温超压。针对存在问题对尿素蒸汽冷凝液系统进行改造,改造后实现了效益的最大化。     

水溶液全循环法尿素新技术应用总结与探讨

山东联盟化工股份有限公司有2套水溶液全循环法小尿素装置，经过多年的技术改造，2004年之前每套装置的生产能力达到了年产150kt，吨尿素蒸汽消耗1500kg左右。为了进一步扩大生产能力和降低蒸汽消耗，2004年5-10月，对其中1套尿素装置进行了较大的技术改造，取得了令人满意的结果。在全面总结这次改造的基础上，2005年1-5月，对另一套尿素装置进行了改造。目前，2套尿素装置年生产能力达到450kt以上，蒸汽消耗大大降低，氨耗也略有下降。下面，对改造内容和运行效果小结如下。     

汽轮机与减温减压系统无扰切换的自控设计

1情况简介 我公司300kt／a尿素装置需用2．45MPa、225℃的中压蒸汽，而锅炉产出的蒸汽为5．0MPa、430℃，待送至尿素装置界区，压力已降为4．3MPa，温度降至410℃左右。传统设计一般用减温减压装置把蒸汽参数降到需要的温度和压力，这样做虽然满足了工艺要求，但造成一定的能源浪费。为了有效利用这一部分能量，我公司把与尿素装置配套的四号循环水站的循环水泵利用背压式汽轮机拖动，背压后的过热蒸汽再经1组减温阀组制成符合工艺要求的饱和蒸汽送往尿素装置，减温减压装置作为备用，当汽轮机出现故障时启用。这样既节约了电能又实现了蒸汽的梯级利用，同时也满足了工艺需要。     

Effect of caustic refining,solvent refining and steam refining on the deacidification and color of rice bran oil

Degummed rice bran oil was deacidified by caustic, solvent and steam refining processes. The steam refining process was optimized through a series of experiments with varying refining times (1–5 hr), temperatures (220–280 C) and amounts of steam (4–20%), at a pressure of 4 mmHg. The most significant factors affecting the degree of deacidification were the refining temperature and amount of steam. The correlation coefficient between quadratic equation obtained and experimental results was 0.96. Acid value and color of steam refined oil were not as good as those of caustic refined oil, but steam refining showed better retention of natural antioxidants than caustic or solvent refining. Steam refining is preferred for deacidification of rice bran oil because of reduced neutral oil loss and elimination of soap production. The important criteria in selecting a deacidification process are known to be the degree of deacidification, neutral oil loss, effect on bleaching and production of soapstock (2,8–10). In comparing caustic refining, solvent refining and steam refining, caustic refining of degummed rice bran oil resulted in satisfactory acid values and color but showed the worst result in neutral oil loss and produced large amounts of soapstock. Solvent refining was not shown to be efficient because of poor deacidification, high losses of neutral oil and darkening of color. Steam refining also was less effective than caustic refining in deacidification and bleaching. However, the degree of deacidification could be improved by development of a process to remove all the free fatty acids (8), and the color problem could be eliminated by including a preliminary bleaching step before steam distillation (10). The application of steam refining to rice bran oil will result in many advantages such as reduced neutral oil loss, no production of soap, and the production of high purity, industrial fatty acids.     

The physical refining process

This paper deals with influences and optimizing of changing process conditions for physical refining of palm oil. These process variables are temperature, pressure, residence time, fluid flow and stripping steam to oil ratio. These parameters influence not only finished oil quality, oil yield, energy consumption and running costs, but also content and yield of natural stabilizers like tocopherols or color compounds like carotenes, and last, but not least, environmental load of waste water and exhaust air as studied under industrial plant conditions. With the right pretreatment process physical refining of palm oil is not only much more economical than chemical refining in connection with stripping steam deodorization, but also causes much less pollution by waste water and exhaust air. Under all these aspects the performance of continuously operated industrial plants now in use for physical refining of palm oil is being examined. Because of the water solubility of the low-boiling thermal degradation products, the effluents of nearly all installations must be specially treated to fulfill today’s legal requirements on BOD and on COD as well as on oil and grease content. The only exception is a new counter-current two-step film type physical refining process in connection with a combined sophisticated steam ejector vacuum and two-step exhaust air washing system, with which, without any air pollution, COD values of <50 for waste water are possible. For best oil quality deacidification should be done with pressure drop of less than 1 torr at 2 to 3 torr tap pressure at 260 C working temperature with residence times of 10 min and counter-current exchange efficiency of 6 to 8 theoretical plates.     

蒸汽发生器在常减压装置中的应用

炼油装置对蒸汽的消耗是除了加热炉燃料油外的最大用能方式之一,炼油装置的低温余热利用是石化装置节能减排的主要工作思路,在常减压装置适当的工艺部位选择合适的热流作为热源,增加蒸汽发生器,再利用适当的低温余热提高换热终温,可替代原来的燃油蒸汽锅炉,节能减排效果显著,经济效益十分可观。     

Steam refining

Steam refining of fatty oils to reduce the partially high free fatty acid content of certain crude oils before conventional refining has been practiced in Europe for many years. Intensive laboratory testing indicated that crude palm oil could be pretreated to remove trace metals and certain heat resistant organic compounds. This pretreated oil could then be steam refined and simultaneously steam deodorized to produce a high quality finished edible oil. Analytical data on crude and finished oil quality and operating yields are presented to illustrate the steam refining/deodorization process. Laboratory results obtained by steam refining a variety of other oils also are presented.     

The effect of bleaching and physical refining on color and minor components of palm oil

An industrially degummed Indonesian palm oil was bleached and steam refined in a pilot plant to study the effect of processing on oil color and on the levels of carotenoids and tocopherols. Five concentrations of one natural and two activated clays mixed with a fixed amount of synthetic silica were used for bleaching. For color measurement, the Lovibond method was compared to the CIE (Commission Internationale de l’Eclairage) L^*,a^*,b^* method. The results showed that the L^*,a^*,b^* method is repeatable and that the values found are highly correlated with the carotenoid content of bleached oil samples. The various clays and synthetic silica mixes removed 20–50% of the carotenoids in the degummed oil, depending on clay concentration and activity. For the two activated clays, pigment adsorption increased with clay amount. Steam refining totally destroyed carotenoids in the claytreated oils by heat bleaching. Total tocopherols in the crude oil amounted to 1000 mg/kg, with γ-tocotrienol as the main tocopherolic component followed by α-tocopherol, α-tocotrienol, and δ-tocotrienol. Tocopherol concentrations increased after the bleaching treatment with the most acid clay, and the increase was proportional to the amount of clay used. Both bleaching and steam refining changed the ratios between the various to copherolic components, especially increasing the relative concentration of α-tocotrienol in the refined oil. An average 80% tocopherol retention was obtained after the treatment with acid clay + synthetic silica and steam refining of palm oil.     

中国碳达峰碳中和目标下炼化一体化新路径与实践

通过对传统炼化一体化流程的思考,本文提出以纵向串联模式分析温度如何强化炼化过程,以横向并联思维归纳炼化工艺。提出通过电供能重构传统的蒸汽裂解技术,获得再电气化下炼化一体化新的技术路线和创新发展空间。文中指出：通过电供能代燃料炉,电烯氢技术及干重整技术不仅使传统的炼油厂和烯烃厂节能减排绿色低碳转型,电供能置换出的干气制合成气及氢用于氢冶金还原铁,二氧化碳捕集、封存及利用（CCUS）,甲醇及汽车生产,也使中国钢铁产业同时脱碳,促进中国CCUS及氢能汽车产业发展,支撑中国2030年碳达峰和2060年碳中和目标实现。     

Comparison of steam and nitrogen in the physical deacidification of soybean oil

Deacidification in physical refining is one of the most sensitive steps in refining edible vegetable oils because of its large impact on the quality of the oil. The removal of volatile compounds such as FFA is accomplished at elevated temperatures and a high vacuum with a stripping gas, usually steam. The aim of this work was to verify, at the laboratory level, the advantages of using an alternative stripping gas, nitrogen, instead of steam. An ideal vapor-liquid equilibrium model (IVLE) was used to compare the stripping capacities of steam and nitrogen and to analyze the effects of various operational parameters (temperature, pressure, amount of stripping gas) on the residual acidity of the oil. There was no clear evidence that nitrogen showed a higher capacity to strip FFA than steam. The IVLE model seemed suitable to describe FFA laboratory distillation by using steam or nitrogen, provided the final residual content of FFA was not too low.     

Physical Refining and Deodorization of Food Oils I

After a general view of fundamental principles for physical refining and deodorization of vegetable oils the requirements regarding oil quality, yield, energy consumption and environmental influence necessary for well-functioning deacidification plants are being discussed. The valuation of the oil quality is effected according to the respective characteristic figures. Decisive for the yield of oil is in the first instance the concentration of the fatty acid distillate obtained. It is reduced by oil drops mechanically entrained by the live steam and is thus a function of quantity and velocity of live steam. Its requirement for oil stripping depends on the working pressure on top, the set working temperature for oil, the obtainable live steam saturation and, above all, on the pressure drop to be overcome by the live steam in the plant. At the same heat exchange between entering and discharging oil, the quantity of live steam required for stripping determines in the end both the direct and the additional utilities to meet the environment protection rules for waste water and exhaust air. Under these aspects the performances of the continuously and semi-continuously operated plants used for industrial purposes are being examined. In order to enable an objective comparison all comparative figures are referring to the deacidification of palm oil with an acid content of approx. 5%by wt.     

炼化企业凝结水的回收与利用

在炼化企业生产中,蒸汽是一种用途极为广泛的能源。蒸汽具有较大的热能,由于蒸汽的热损失问题,蒸汽一直是节能问题的焦点,蒸汽在经过换热器放出潜热后凝结成同温同压下的高温凝结水。凝结水的回收与利用是企业特别是炼油企业节能的一项重要措施。