萘又称井萘是一种无色有光泽的片状结晶。不溶于水,易升华,能随水蒸气挥发,有特殊气味。是工业上最重要的稠环芳经可用于生产苯酐、染料的中间体、橡胶助剂和杀虫剂。

Naphthalene, also known as well naphthalene, is a colorless and glossy crystalline flake. Insoluble in water, prone to sublimation, can evaporate with water vapor, and has a special odor. It is the most important polycyclic aromatic hydrocarbon in industry that can be used as an intermediate in the production of phthalic anhydride, dyes, rubber additives, and insecticides.

根据纯度不同,萘可分为工业蔡和精萘。工业蔡的纯度一般约为96%。工业蔡进一步提纯脱除杂质及脱硫后,可得到高纯度的精萘。

According to different purities, naphthalene can be divided into industrial naphthalene and refined naphthalene. The purity of industrial Cai is generally about 96%. After further purification and removal of impurities and desulfurization, industrial Cai can obtain high-purity refined naphthalene.

生产和制备简介：

Introduction to Production and Preparation:

1.从石油烃类制造：催化重整油，轻循环油催化裂化，乙烯裂解副产物焦油等；

1. Manufacturing from petroleum hydrocarbons: catalytic reforming oil, light cycle oil catalytic cracking, ethylene cracking by-product tar, etc;

2.与煤焦油分离，高温煤焦油中的萘约占8％-12％。将煤焦油蒸馏，将煤油切碎，并通过脱酚和脱喹啉蒸馏获得最终的萘。

2. Separation from coal tar, naphthalene in high-temperature coal tar accounts for about 8% -12%. Distill the coal tar, cut the kerosene into small pieces, and obtain the final naphthalene through dephenolization and quinoline removal distillation.

3.精萘是将粗萘精制而成。

3. Refined naphthalene is refined from crude naphthalene.

4.降膜分步结晶结晶生产工艺流程由产品生产工艺系统，能量系统，氮气密封系统和计算机控制系统组成。生产过程系统将大周期用作生产周期。每个大周期包含4个小周期，每个小周期包含4至6个段。每个段包括3个步骤：结晶，部分熔融和全部熔融；

The production process of falling film fractional crystallization crystallization consists of a product production process system, an energy system, a nitrogen sealing system, and a computer control system. The production process system uses large cycles as production cycles. Each large cycle contains 4 small cycles, and each small cycle contains 4 to 6 segments. Each section includes three steps: crystallization, partial melting, and complete melting;

（从工业萘装置送来的液态工业萘被送到馏出罐，当进行第四阶段结晶操作时，罐中的原料液体被送到动态结晶器收集槽

The liquid industrial naphthalene sent from the industrial naphthalene unit is sent to the distillation tank. When the fourth stage crystallization operation is carried out, the raw material liquid in the tank is sent to the dynamic crystallizer collection tank

未结晶的萘油和汗液放入纯度较低的分馏罐中，并且在第五阶段中可以将全部熔体用作原料。可以根据预定程序在六个阶段的晶体精制之后获得精致的萘。为了提高萘的萃取率，可以将富含硫茚的馏分送入静态结晶器进行处理。从静态结晶器中获得的产品返回到动态结晶系统的相应分馏罐中，残留液体可以作为减水剂出售。由于该设备同时使用动态和静态结晶器，因此不仅可以确保更高的萘回收率，而且可以减少能耗。 ）

Uncrystallized naphthalene oil and sweat are placed in a lower purity fractionation tank, and in the fifth stage, all the melt can be used as raw materials. Refined naphthalene can be obtained after six stages of crystal refinement according to the predetermined program. In order to improve the extraction rate of naphthalene, the fraction rich in sulfur indene can be sent to a static crystallizer for processing. The product obtained from the static crystallizer is returned to the corresponding distillation tank of the dynamic crystallization system, and the residual liquid can be sold as a water reducing agent. Due to the use of both dynamic and static crystallizers, this device not only ensures higher naphthalene recovery rates but also reduces energy consumption

5.静态逐步结晶将原料工业萘装入结晶箱中，然后快速冷却至82°C。之后，将其以2°C/h的冷却速率均匀冷却至60°C，即排放量丰富。硫代茚的萘油的第一次结晶用作中间馏分进行后处理。然后将结晶箱中的物料以4°C/h的速率加热，并以0.5h的间隔取样，并测量结晶点。根据不同的结晶点，它们被排入相应的分馏罐。这样，可以进行3至4次结晶。获得了更高纯度的精制萘。

5. Static stepwise crystallization: The raw material industrial naphthalene is loaded into a crystallization box and then rapidly cooled to 82 ° C. Afterwards, cool it uniformly at a cooling rate of 2 ° C/h to 60 ° C, which results in abundant emissions. The first crystallization of naphthalene oil containing thioindene is used as an intermediate fraction for post-treatment. Then heat the material in the crystallization box at a rate of 4 ° C/h, take samples at intervals of 0.5 hours, and measure the crystallization point. According to different crystallization points, they are discharged into the corresponding distillation tanks. In this way, 3 to 4 crystallization cycles can be carried out. Obtained higher purity refined naphthalene.