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.

該廠采用溶劑法純化提取精萘技術，具有工藝簡單，設備投資少，節約能源等優點。

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溫度下溶解的化學性質，采用相應的溶劑，使萘全部溶解控制結晶速度，使萘在適當的濕度下重結晶，從而制得精萘，回收率達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、由煤焦油分離，高溫煤焦油中萘約占8%～12%，將煤焦油蒸餾，切取煤油，經脫酚，脫，蒸餾得成品萘。 每噸萘消耗lOt煤焦油。 由石油烴制得：催化重質重整油，催化裂化輕循環油，裂解制的副產焦油等。 更新：2022-01-010:39:5精萘 - 用途 開放數據 可信數據 為基本化工原料，主要用于生產、各種萘酚、萘胺等，是生產合成樹脂、增塑劑、橡膠防老劑、表面活性劑、合成纖維、染料、涂料、農藥、醫藥和香料等的原料。 更新：2022-01-010:39:5精萘 - 安全性 開放數據 可信數據 萘的水溶性較小，而且不易被吸收，故其毒性不太強。 吸入濃的萘蒸氣或萘粉末時，能促使人嘔吐，不適，頭痛。

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、 工業萘 熔 萘 生產過程控制 1投料 先向引風機過濾桶加水至網板，然后開啟引風機，蒸 汽閥及槽蓋，將工業萘投入9#槽，待全部溶化后關蒸汽閥， 槽蓋及引風機。 投料結束將吸收的萘粉塵和底水放入回收池并清洗吸 收桶。 2進2#槽餾份操作  1先將循環水溫調整在75 C -80 C之間后，開始進料，在 進料的同時，進行冷卻，進料結束，水溫控制在60 °C -6°C , 繼續降溫至38~40 C ,降溫速度每小時不得超過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、當前精萘的生產方法，有結晶法、加氫精制法、酸洗蒸餾法、升華法等。 傳統的方法是酸洗法，由于產生廢酸，造成環境污染，如今被結晶法和加氫精制法取代。 1結晶法結晶法分為熔融結晶法和溶劑結晶法。 熔融結晶法的原理是基于混合物中各組分在相變時有重分布現象。 溶劑結晶法是利用萘與雜質在醇類中溶解度的差異使萘得到凈化。 溶劑結晶法使用的溶劑多數采用，揮發性較大且有毒，并且實際生產中采用熔融結晶法的較多，所以下面介紹幾種熔融結晶法：1間歇式分布結晶法—Prosbd此法是由20世紀60年代法國Prosbd公司開發。 本法在捷克烏爾克斯焦油加工廠實施。 主要設備是8個結晶箱，分4步進行。 結晶箱的升溫和降溫通過一臺泵、一臺加熱器和一臺冷卻器與結晶箱串聯起來實現。

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、精餾塔頂逸出的工業萘蒸汽在熱交換器中與原料換熱后進入汽化冷凝冷卻器，冷凝冷卻后的液態工業萘流入回流槽，一部分作為精餾塔回流，另一部分進入工業萘貯槽后，再經轉鼓結晶機冷卻結晶成片狀結晶，即工業萘產品。 精餾塔底的殘油用熱油泵送至管式爐加熱后返回塔底，以供給精餾塔熱量。 同時在熱油泵出口分出一部分殘油經冷卻后進入貯。 B、單爐雙塔工藝流程 單爐雙塔流程與雙爐雙塔流程差別僅在于，單爐雙塔管式加熱爐輻射段分為兩組。 初餾塔底油用熱油泵送入管式爐對流段和輻射段的其中一組加熱后，再返回初餾塔塔底蒸發段以循環供熱。

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、節工業萘的生產工業萘生產工藝流程（一）雙爐雙塔工業萘連續精餾流程所謂雙爐雙塔，是指該流程中采用了兩臺管式爐、兩座精餾塔（初餾塔和精餾塔）。

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-萘酚生產工藝 利用工業萘為主要原料生產精萘和 2-萘酚。 生產過程主要包括: 工業萘精制和利用 精萘生產 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—原料與工業萘換熱器；4—初餾塔；

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