The purity of industrial naphthalene is required to be more than 95.5%, which is not acceptable if it is lower. Generally, refined naphthalene is used as raw material for phthalic anhydride produced by naphthalene process, which is more than 97%.

上世紀(jì)80年代開(kāi)始由德國(guó)BASF公司開(kāi)發(fā)的工業(yè)萘流化床法制苯酐，后來(lái)又開(kāi)發(fā)出了鄰二甲苯法制苯酐。萘法逐漸被取代，直到近幾年，由于鄰二甲苯價(jià)格高，原料不易采購(gòu)，而工業(yè)萘原料充足，價(jià)格較低，加之新的工藝及專用催化劑的研制，使萘法苯酐工藝又熱門起來(lái)！

In the 1980s, the industrial naphthalene fluidized bed process for phthalic anhydride was developed by BASF in Germany, and then the o-xylene process for phthalic anhydride was developed. Naphthalene process is gradually replaced. Until recent years, due to the high price of o-xylene, raw materials are not easy to purchase, while industrial naphthalene raw materials are abundant and low in price. In addition, new processes and the development of special catalysts have made naphthalene phthalic anhydride process popular again!

萘法苯酐，普遍采用的是固定床空氣催化氧化法。催化劑有BASF的04-29專用催化劑和大連龍翔的催化劑。

Naphthalene phthalic anhydride generally adopts fixed bed air catalytic oxidation method. The catalysts include BASF's 04-29 special catalyst and Dalian Longxiang's catalyst.

工藝流程簡(jiǎn)單說(shuō)有：

The process flow simply includes:

1、粗制苯酐：工業(yè)萘汽化，空氣壓縮，氧化反應(yīng)，切換冷凝，尾氣處理；

1. Crude phthalic anhydride: industrial naphthalene vaporization, air compression, oxidation reaction, switching condensation, tail gas treatment;

2、苯酐精制：預(yù)熱，熟化，脫輕，苯酐精制，殘?jiān)幚恚?/div>