1、 Tar naphthalene

从煤焦油中分离出来的萘称之为焦油萘 。在高温煤焦油中萘约占8-12% 。从焦油精馏塔侧线切取出温度区间为210-230℃的萘油馏分，经过洗涤脱酚，再精馏分离轻组分，便可得到凝固点为78℃、纯度为96%的工业萘 。

Naphthalene separated from coal tar is called tar naphthalene. In high-temperature coal tar, naphthalene accounts for about 8-12%. Naphthalene oil fraction with a temperature range of 210-230 ℃ is cut from the side line of the tar distillation tower, washed and dephenolized, and then distilled to separate the light components to obtain industrial naphthalene with a freezing point of 78 ℃ and a purity of 96%.

工业萘中含杂质硫茚(1-3%)、甲基萘(1-2%)及少量茚、焦油碱和焦油酸，经过进一步酸洗和蒸馏，可得到硫含量小于0.1%、凝固点为79℃的精萘 。若需要进一步精制使硫含量低于0.05%，则需采用加氢精制工艺 。

Industrial naphthalene contains impurities such as indene (1-3%), methylnaphthalene (1-2%) and a small amount of indene, tar base and tar acid. After further pickling and distillation, refined naphthalene with sulfur content less than 0.1% and freezing point of 79 ℃ can be obtained. If further refining is required to make the sulfur content lower than 0.05%, the hydrofining process is required.

二、石油萘

2、 Petroleum naphthalene

石油萘的原料来自于催化重整、催化裂化和烃类裂解等过程的重芳烃组分 。在催化重整油中，甲基萘的含量约为55% 。首先经过萃取和吸附，从原料馏分中分离出萘的各种同系物，然后采用催化临氢脱烷基的方法，以Cr2O3-Al2O3为催化剂，在400-800℃和0.5-7兆帕下进行临氢脱甲基反应，反应产物经冷却气相物质后，蒸馏除去轻组分苯、甲苯、二甲苯等，最后进一步精馏可得到石油萘产品 。

The raw material of petroleum naphthalene comes from the heavy aromatics components in catalytic reforming, catalytic cracking and hydrocarbon cracking. In the catalytic reforming oil, the content of methyl naphthalene is about 55%. First, various homologues of naphthalene are separated from the raw material fraction through extraction and adsorption, and then the hydrogenation demethylation reaction is carried out with Cr2O3-Al2O3 as catalyst at 400-800 ℃ and 0.5-7 MPa by catalytic hydrodealkylation method. The reaction product is cooled by gas phase substances, and the light components such as benzene, toluene, xylene, etc. are removed by distillation. Finally, the petroleum naphthalene product can be obtained by further distillation.

产品用溶剂吸收和溶剂洗涤的方法进行提纯，纯度可达99.73% 。

The product is purified by solvent absorption and solvent washing, and the purity can reach 99.73%.

据估计，以轻柴油为裂解原料的年产30万吨的乙烯装置，，可副产焦油9万吨，其中萘和萘潜量为4-5万吨 。

It is estimated that an ethylene plant with an annual output of 300000 tons using light diesel oil as cracking feedstock can produce 90000 tons of tar by side, of which naphthalene and naphthalene have a potential of 40000 to 50000 tons.