萘是煤焦油中含量高的双环化合物，是有机合成工业中重要的原料之一，是生产活性染料、酸性染料、直接染料、炸药、H-酸、β-萘酚、苯酐等精细化工产品必需原料。目前国内大部分焦化厂只生产工业萘或压榨萘，以此为原料生产的产品，杂质较多，给分离精制增加困难。因此精萘十分紧缺，一直供不应求。

Naphthalene is a bicyclic compound with high content in Coal tar. It is one of the important raw materials in the organic synthesis industry. It is used to produce Reactive dye, acid dyes, direct dyes, explosives, H-acid β- Essential raw materials for fine chemical products such as naphthol and phthalic anhydride. At present, most coking plants in China only produce industrial naphthalene or pressed naphthalene. The products produced from this raw material have many impurities, which increases the difficulty of separation and refining. Therefore, refined naphthalene is very scarce and has been in short supply.

目前，国内精萘已实现工业化生产的主要有区域熔融法、分步熔融结晶（箱法）及化学法等。下面精萘厂家为您分析：

At present, the main industrial production methods for refined naphthalene in China include regional melting method, step-by-step melting crystallization (box method), and chemical method. The following refined naphthalene manufacturers will analyze for you:

区域熔融工艺的特点是：精萘纯度高、处理量大，基本上没有环境污染。但是，技术复杂、设备一次投资相当大。精萘机的操作条件控制要求相当严格。各段温度梯度控制精度要求在05℃以内。目前采用该技术常由电脑控制系统。相应地操作人员的技术素质要求很高，操作程序不易掌握。

The characteristics of regional melting process are: high purity of refined naphthalene, large processing capacity, and basically no environmental pollution. However, the technology is complex and the one-time investment in equipment is considerable. The operating conditions control requirements of the naphthalene refining machine are quite strict. The temperature gradient control accuracy of each section is required to be within 05 ℃. Currently, this technology is often controlled by a computer system. Correspondingly, the technical quality requirements of operators are high, and the operating procedures are not easy to master.

熔融分步结晶法初为法国Proabd公司专利，六十年代先后在英国和捷克建厂投入生产。但此后未在国际上进一步推广。其主要原因是设备庞大，操作周期长。

The melting step crystallization method was initially patented by Proabd Company in France and was put into production in the UK and Czech Republic in the 1960s. But it has not been further promoted internationally since then. The main reason is that the equipment is large and the operation cycle is long.

化学法萘精制工艺已生产多年，面临淘汰。主要原因是工艺流程太长，萘的回收率较低。仅洗涤过程中，纯萘的损失量约5%。生产需要较大量的浓硫酸和烧碱，而且一般不能回收利用，所以，环境污染严重，工人操作条件比较恶劣，设备腐蚀严重，生产成本较高。

The chemical naphthalene refining process has been in production for many years and is facing elimination. The main reason is that the process flow is too long and the recovery rate of naphthalene is low. During the washing process alone, the loss of pure naphthalene is about 5%. Production requires a large amount of concentrated sulfuric acid and caustic soda, and generally cannot be recycled. Therefore, environmental pollution is severe, workers' operating conditions are relatively poor, equipment corrosion is severe, and production costs are high.

本发明的目的是提供一种足以克服上述缺点的溶剂结晶法制取精萘工艺，它设备简单，操作容易，周期短，产品质量稳定，无环境污染。

The purpose of the present invention is to provide a solvent crystallization process for preparing refined naphthalene that is sufficient to overcome the aforementioned drawbacks. The process has simple equipment, easy operation, short cycle, stable product quality, and no environmental pollution.

1.一种溶剂结晶法制取精萘工艺，其特征是所用原料为萘渣或焦油渣，蒸馏截取210～230℃时的馏分，也可直接采用工业萘或水萘，将回收的馏分或工业萘、水萘置入反应釜内，再加入有机溶剂，其用量与原料用量的重量比为2.5～3.5∶1，加温至70～80℃，使全部原料溶解，然后逐渐降温至30～15℃，重新结晶，再进入离心机分离，将分离出的溶剂回收再用，分离出的精萘干燥后即成产品。

1. A solvent crystallization process for producing refined naphthalene, characterized in that the raw material used is naphthalene residue or tar residue, and the distillate at 210~230 ℃ is cut off by distillation. Industrial naphthalene or water naphthalene can also be directly used. The recovered fraction, industrial naphthalene, and water naphthalene are placed in a reactor, and then organic solvents are added. The weight ratio of the amount to the amount of raw materials is 2.5~3.5:1. The process is heated to 70~80 ℃ to dissolve all the raw materials, and then gradually cooled to 30~15 ℃, Recrystallize and then enter a centrifuge for separation. The separated solvent is recycled and reused, and the separated naphthalene is dried to form the product.

国内精萘已实现工业化生产的主要方法相关内容就讲解到这里了，希望能够给您好的帮助，更多事项就来我们网站http://www.jnjdbc.cn咨询吧！

That's all for the main methods of industrialized production of refined naphthalene in China. We hope to provide you with good help. For more information, please come to our website http://www.jnjdbc.cn Consult!