China's refined naphthalene is mostly produced using the "distributed melting crystallization method" (box method), which has a long process flow, high equipment investment, complex technology, and low recovery rate.

该厂采用溶剂法纯化提取精萘技术，具有工艺简单，设备投资少，节约能源等优点。

The factory adopts solvent purification and extraction technology for refined naphthalene, which has the advantages of simple process, low equipment investment, and energy conservation.

它是利用精萘在一定温度下溶解的化学性质，采用相应的溶剂，使萘全部溶解控制结晶速度，使萘在适当的湿度下重结晶，从而制得精萘，回收率达９２％。

It utilizes the chemical properties of refined naphthalene dissolved at a certain temperature, using corresponding solvents to completely dissolve the naphthalene and control the crystallization rate. The naphthalene is recrystallized at appropriate humidity to obtain refined naphthalene with a recovery rate of 92%.

1、由煤焦油分离，高温煤焦油中萘约占8%～12%，将煤焦油蒸馏，切取煤油，经脱酚，脱，蒸馏得成品萘。 每吨萘消耗lOt煤焦油。 由石油烃制得：催化重质重整油，催化裂化轻循环油，裂解制的副产焦油等。 更新：2022-01-010:39:5精萘 - 用途 开放数据 可信数据 为基本化工原料，主要用于生产、各种萘酚、萘胺等，是生产合成树脂、增塑剂、橡胶防老剂、表面活性剂、合成纤维、染料、涂料、农药、医药和香料等的原料。 更新：2022-01-010:39:5精萘 - 安全性 开放数据 可信数据 萘的水溶性较小，而且不易被吸收，故其毒性不太强。 吸入浓的萘蒸气或萘粉末时，能促使人呕吐，不适，头痛。

1. By separating coal tar, naphthalene accounts for about 8% to 12% of the high-temperature coal tar. The coal tar is distilled, cut into kerosene, and subjected to dephenolization, dephenolization, and distillation to obtain finished naphthalene. Each ton of naphthalene consumes lOt of coal tar. Produced from petroleum hydrocarbons: catalytic heavy reforming oil, catalytic cracking light circulating oil, by-product tar from cracking, etc. Update: January 1, 2022-010:39:5 Refined Naphthalene - Purposes Open Data Trusted Data is a basic chemical raw material mainly used for production, various naphthols, naphthylamines, etc. It is a raw material for the production of synthetic resins, plasticizers, rubber antioxidants, surfactants, synthetic fibers, dyes, coatings, pesticides, pharmaceuticals, and fragrances. Update: January 2022-010:39:5 Refined Naphthalene - Safety Open Data Trusted Data Naphthalene has low water solubility and is not easily absorbed, so its toxicity is not very strong. Inhaling concentrated naphthalene vapor or naphthalene powder can cause vomiting, discomfort, and headaches.

2、 工业萘 熔 萘 生产过程控制 1投料 先向引风机过滤桶加水至网板，然后开启引风机，蒸 汽阀及槽盖，将工业萘投入9#槽，待全部溶化后关蒸汽阀， 槽盖及引风机。 投料结束将吸收的萘粉尘和底水放入回收池并清洗吸 收桶。 2进2#槽馏份操作  1先将循环水温调整在75 C -80 C之间后，开始进料，在 进料的同时，进行冷却，进料结束，水温控制在60 °C -6°C , 继续降温至38~40 C ,降温速度每小时不得超过5C。

2. Production process control of industrial naphthalene melting: 1. Feed: First, add water to the filter barrel of the induced draft fan to the mesh plate, then open the induced draft fan, steam valve, and tank cover. Then, put the industrial naphthalene into tank 9 #, and after all is dissolved, close the steam valve, tank cover, and induced draft fan. After feeding, place the absorbed naphthalene dust and bottom water into the recycling tank and clean the absorption bucket. After adjusting the circulating water temperature between 75 ° C and 80 ° C, start feeding and cool down at the same time. After feeding, control the water temperature at 60 ° C -6 ° C and continue to cool down to 38-40 ° C, with a cooling rate not exceeding 5 ° C per hour.

3、当前精萘的生产方法，有结晶法、加氢精制法、酸洗蒸馏法、升华法等。 传统的方法是酸洗法，由于产生废酸，造成环境污染，如今被结晶法和加氢精制法取代。 1结晶法结晶法分为熔融结晶法和溶剂结晶法。 熔融结晶法的原理是基于混合物中各组分在相变时有重分布现象。 溶剂结晶法是利用萘与杂质在醇类中溶解度的差异使萘得到净化。 溶剂结晶法使用的溶剂多数采用，挥发性较大且有毒，并且实际生产中采用熔融结晶法的较多，所以下面介绍几种熔融结晶法：1间歇式分布结晶法—Prosbd此法是由20世纪60年代法国Prosbd公司开发。 本法在捷克乌尔克斯焦油加工厂实施。 主要设备是8个结晶箱，分4步进行。 结晶箱的升温和降温通过一台泵、一台加热器和一台冷却器与结晶箱串联起来实现。

3. The current production methods of refined naphthalene include crystallization, hydrofining, acid washing distillation, sublimation, etc. The traditional method is acid washing, which has been replaced by crystallization and hydrofining due to the generation of waste acid and environmental pollution. The crystallization method is divided into melt crystallization method and solvent crystallization method. The principle of melt crystallization method is based on the phenomenon of redistribution of each component in the mixture during phase transition. The solvent crystallization method utilizes the difference in solubility between naphthalene and impurities in alcohols to purify naphthalene. The solvents used in solvent crystallization method are mostly volatile and toxic, and in actual production, melting crystallization method is commonly used. Therefore, several melting crystallization methods are introduced below: 1. Intermittent distributed crystallization method - Prosbd. This method was developed by Prosbd Company in France in the 1960s. This law is implemented at the Ulx Tar Processing Plant in Czech Republic. The main equipment is 8 crystallization boxes, which are divided into 4 steps. The heating and cooling of the crystallization box are achieved by connecting a pump, a heater, and a cooler in series with the crystallization box.

4、精馏塔顶逸出的工业萘蒸汽在热交换器中与原料换热后进入汽化冷凝冷却器，冷凝冷却后的液态工业萘流入回流槽，一部分作为精馏塔回流，另一部分进入工业萘贮槽后，再经转鼓结晶机冷却结晶成片状结晶，即工业萘产品。 精馏塔底的残油用热油泵送至管式炉加热后返回塔底，以供给精馏塔热量。 同时在热油泵出口分出一部分残油经冷却后进入贮。 B、单炉双塔工艺流程 单炉双塔流程与双炉双塔流程差别仅在于，单炉双塔管式加热炉辐射段分为两组。 初馏塔底油用热油泵送入管式炉对流段和辐射段的其中一组加热后，再返回初馏塔塔底蒸发段以循环供热。

4. The industrial naphthalene steam that escapes from the top of the distillation tower exchanges heat with the raw materials in the heat exchanger and enters the vaporization condenser. After condensation and cooling, the liquid industrial naphthalene flows into the reflux tank. Part of it serves as the reflux of the distillation tower, and the other part enters the industrial naphthalene storage tank. After cooling by a rotary drum crystallizer, it crystallizes into flake like crystals, which are industrial naphthalene products. The residual oil at the bottom of the distillation tower is heated by a hot oil pump and then returned to the bottom of the tower to supply heat to the distillation tower. At the same time, a portion of residual oil is separated from the outlet of the hot oil pump and cooled before entering storage. B. The difference between the single furnace double tower process and the double furnace double tower process is only that the radiation section of the single furnace double tower tubular heating furnace is divided into two groups. The bottom oil of the initial distillation tower is fed into one of the convection and radiation sections of the tube furnace using a hot oil pump for heating, and then returned to the evaporation section of the initial distillation tower bottom for circulating heating.

5、节工业萘的生产工业萘生产工艺流程（一）双炉双塔工业萘连续精馏流程所谓双炉双塔，是指该流程中采用了两台管式炉、两座精馏塔（初馏塔和精馏塔）。

5. The production process flow of industrial naphthalene is as follows: (1) The continuous distillation process of industrial naphthalene with two furnaces and two towers. The so-called double furnace and two towers refers to the use of two tube furnaces and two distillation towers (primary distillation tower and distillation tower) in this process.

6、精萘、2-萘酚生产工艺 利用工业萘为主要原料生产精萘和 2-萘酚。 生产过程主要包括: 工业萘精制和利用 精萘生产 2-萘酚。

6. The production process of refined naphthalene and 2-naphthol utilizes industrial naphthalene as the main raw material to produce refined naphthalene and 2-naphthol. The production process mainly includes industrial naphthalene refining and the use of refined naphthalene to produce 2-naphthol.

7、1—原料槽；2—原料泵；3—原料与工业萘换热器；4—初馏塔；

7. 1- Raw material tank; 2- Raw material pump; 3- Raw material and industrial naphthalene heat exchanger; 4- Initial distillation tower;