精萘是一種重要的有機(jī)化工原料，廣泛應(yīng)用于染料、醫(yī)藥、塑料、農(nóng)藥等領(lǐng)域。其提取主要依賴(lài)于煤焦油和石油化工副產(chǎn)物，以下是當(dāng)前工業(yè)中主流的提取與精制方法：

Naphthalene is an important organic chemical raw material widely used in fields such as dyes, pharmaceuticals, plastics, pesticides, etc. Its extraction mainly relies on coal tar and petrochemical by-products. The following are the mainstream extraction and refining methods in the current industry:

一、煤焦油提取法（傳統(tǒng)主流工藝）

1、 Coal tar extraction method (traditional mainstream process)

煤焦油是煤炭干餾的副產(chǎn)物，其中萘的含量約為 8%-12%，是提取精萘的主要原料。具體流程如下：

Coal tar is a by-product of coal dry distillation, with a naphthalene content of about 8% -12%, and is the main raw material for extracting refined naphthalene. The specific process is as follows:

1. 原料預(yù)處理與分餾

1. Raw material pretreatment and fractionation

分餾切取萘油餾分：將煤焦油在蒸餾塔中加熱，按沸點(diǎn)范圍切取**210-270℃**的餾分段（稱(chēng)為 “萘油” 或 “中油”），其中萘含量可達(dá) 50%-70%，同時(shí)含有酚類(lèi)、喹啉、甲基萘等雜質(zhì)。

Fractionation and extraction of naphthalene oil fractions: Coal tar is heated in a distillation tower and a fraction of * * 210-270 ℃ * * is extracted according to the boiling point range (referred to as "naphthalene oil" or "middle oil"), with a naphthalene content of up to 50% -70% and impurities such as phenols, quinolones, and methyl naphthalene.

2. 粗萘分離

2. Separation of crude naphthalene

冷卻結(jié)晶與離心：將萘油冷卻至50-60℃，萘從油中結(jié)晶析出，通過(guò)離心機(jī)分離得到粗萘（純度約 90%-95%），雜質(zhì)主要為酚類(lèi)、喹啉及高沸點(diǎn)油類(lèi)。

Cooling crystallization and centrifugation: naphthalene oil is cooled to 50-60 ℃, and naphthalene crystallizes and precipitates from the oil. Crude naphthalene (with a purity of about 90% -95%) is separated by centrifugation, and impurities mainly include phenols, quinolines, and high boiling point oils.

3. 粗萘精制

3. Crude naphthalene refining

溶劑洗滌除雜：

Solvent washing for impurity removal:

用濃硫酸洗滌粗萘，去除其中的不飽和烴和酚類(lèi)雜質(zhì)；

Wash crude naphthalene with concentrated sulfuric acid to remove unsaturated hydrocarbons and phenolic impurities;

再用氫氧化鈉溶液中和殘留酸，水洗后干燥。

Neutralize the residual acid with sodium hydroxide solution, wash with water, and then dry.

升華或蒸餾精制：

Sublimation or distillation refinement:

升華法：利用萘的升華特性（熔點(diǎn) 80.2℃，沸點(diǎn) 218℃），在加熱條件下使萘直接從固態(tài)變?yōu)闅鈶B(tài)，冷凝后得到純度≥99% 的精萘。

Sublimation method: Utilizing the sublimation properties of naphthalene (melting point 80.2 ℃, boiling point 218 ℃), naphthalene is directly transformed from solid to gas under heating conditions, and condensed to obtain refined naphthalene with a purity of ≥ 99%.

蒸餾法：將粗萘在蒸餾塔中減壓蒸餾，利用各組分沸點(diǎn)差異分離，餾出的萘蒸氣冷凝后即為精萘。

Distillation method: Crude naphthalene is distilled under reduced pressure in a distillation tower, and the boiling point differences of each component are used to separate it. The distilled naphthalene vapor is condensed and becomes refined naphthalene.

二、石油化工副產(chǎn)物提取法（新興工藝）

2、 Extraction method of by-products from petrochemical industry (emerging process)

隨著石油化工的發(fā)展，從催化重整生成的重芳烴（如石腦油重整副產(chǎn)物）中提取萘成為補(bǔ)充途徑，流程如下：

With the development of petrochemicals, extracting naphthalene from heavy aromatic hydrocarbons generated by catalytic reforming (such as by-products of naphtha reforming) has become a supplementary pathway. The process is as follows:

1. 重芳烴分離

1. Separation of heavy aromatic hydrocarbons

催化重整生成的重芳烴中含有萘及烷基萘，通過(guò)溶劑萃取（如環(huán)丁砜、二甲基亞砜）或結(jié)晶法（利用低溫下萘的結(jié)晶特性）分離出萘的富集物。

The heavy aromatic hydrocarbons generated by catalytic reforming contain naphthalene and alkyl naphthalene, and the enriched naphthalene can be separated by solvent extraction (such as sulfolane, dimethyl sulfoxide) or crystallization (utilizing the crystallization characteristics of naphthalene at low temperatures).

2. 催化加氫精制

2. Catalytic hydrogenation refining

對(duì)富集物進(jìn)行催化加氫，去除硫、氮等雜質(zhì)，同時(shí)將烷基萘轉(zhuǎn)化為萘，再通過(guò)蒸餾或結(jié)晶得到精萘。

Catalytic hydrogenation of the enriched material to remove impurities such as sulfur and nitrogen, while converting alkyl naphthalene to naphthalene, and then obtaining refined naphthalene through distillation or crystallization.

該方法所得精萘純度高（≥99.5%），雜質(zhì)少，適合高端應(yīng)用場(chǎng)景。

The purity of refined naphthalene obtained by this method is high (≥ 99.5%), with few impurities, suitable for high-end application scenarios.

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