我国维生素C生产过程甲醇挥发损失的估算

通过对我国主要维生素C生产厂家的生产工艺及主要VOCs甲醇的排放节点(包括酯化反应、离心机排气、精馏塔尾气、储罐呼吸)的调研和分析,结合行业协会和国家统计局统计的数据,利用生产过程物料衡算和中国石油化工系统经验公式,估算了生产单位质量(103 t)维生素C各排放节点甲醇的挥发损失量,并且建立了2007—2011年主要维生素C生产厂家甲醇的年挥发损失清单. 结果表明:生产单位质量维生素C时,酯化反应节点甲醇的挥发损失量为4.25 t/103　t,离心机排气为3.36 t/103　t,精馏塔尾气为0.63 t/103　t,储罐呼吸为0.35 t/103　t；甲醇挥发损失主要集中在酯化反应和离心机排气2个排放节点,二者挥发损失量各占排放节点挥发损失总量的50%和39%；2007—2011年我国10家主要维生素C生产厂家甲醇的年挥发损失总量已达1 000 t以上. 

Estimation of Methanol Volatilization Loss from Vitamin C Production Processes in China

Methanol volatilization in the production of vitamin C from each emission node was estimated based on investigation and analysis of major vitamin C production facilities as well as methanol emission nodes including the fermentation process, centrifugal exhaust, rectification tower exhaust and tank breathing. The analysis was based on data from pharmaceutical associations and the National Bureau of Statistics, the use of material balance principle in production processes and China petrochemical empirical formulas. An annual methanol emissions inventory of typical pharmaceutical production facilities in China was established from 2007 to 2011. The results showed that methanol volatilization was 4.25 t/103　t in esterification reactions, 3.36 t/103　t in centrifugal exhaust, 0.63 t/103　t in rectification tower exhaust and 0.35 t/103　t in tank breathing. The main two emission nodes producing methanol were the esterification reaction and centrifugal exhaust, which accounted for 50% and 39% of the total volatilization loss, respectively. The annual methanol volatilization from 2007 to 2011 in ten vitamin C pharmaceutical production facilities was relatively high, and the total volatilization of major production facilities reached more than 1000 tons in recent years.