(560d) The Green Production Process of ?-Caprolactam with Vapor-Phase Beckmann Rearrangement | AIChE

(560d) The Green Production Process of ?-Caprolactam with Vapor-Phase Beckmann Rearrangement

Authors 

Wang, H. - Presenter, RIPP, Sinopec
Cheng, S., RIPP, Sinopec
Fan, Y., RIPP, Sinopec
Xie, L., RIPP, Sinopec
Jiang, Y., RIPP, Sinopec
Yang, K., RIPP, Sinopec
Zong, B., RIPP, Sinopec

The Green Production Process
of
¦Å-caprolactam with Vapor-Phase
Beckmann Rearrangement
 

Hao Wang, Shibiao Cheng, Yingqi
Fan, Li Xie, Yusheng Jiang, Keyong
Yang, Baoning Zong

Process Develop Department,
Research Institute of Petroleum Processing (RIPP), SINOPEC, Beijing 100083, P. R. China ¨C wanghao.ripp@sinopec.com;                                                        

Keywords: ¦Å-caprolactam, vapor-phase, Beckmann rearrangement

1       
 Introduction

Vapor-phase Beckmann rearrangement is a
green, free-ammonium sulfate ¦Å-caprolactam production process. With the increasing demand for
¦Å-caprolactam, this process has been widely concerned. The existing liquid-phase
method, as shown in Eq.(1), uses sulfuric acid as a
catalyst, and produces about 1.5 tons of ammonium sulfate per ton of ¦Å-caprolactam,
which will be a great burden of ¦Å-caprolactam enterprises in the future. Compared with the
existing processes, the vapor-phase rearrangement process, as shown in Eq.(2), has the advantages of low equipment corrosion, low
waste water discharge, high product quality, safe and stable operation, and
thus has a broad market development prospect as a new generation of ¦Å-caprolactam
production process.

2       
 The production process of ¦Å-caprolactam with vapor-phase Beckmann rearrangement

The process consists of vapor-phase Beckmann rearrangement reaction unit and  crystallization refining unit. The determined process conditions and process flow are quite
different from those of the existing HPO process.

 The vapor-phase Beckmann rearrangement process is
a gas phase reaction process, which requires cyclohexanone oxime to
participate in the reaction with gas phase. However, due
to its heat-sensitive characteristics, its vaporization problem is the primary
problem in the development of vapor-phase
Beckmann rearrangement process. Secondly, since
the reaction proceeds at a high temperature, the product distribution
characteristics determine that the refining process requires a crystallization
method with high-efficiency separation method. In the process
of crystallization process development, the high quality product was been obtained. RIPP-SINOPEC relies on 800
tons/year cyclohexanone oxime vapor-phase Beckmann rearrangement pilot equipment
device
to solve lot problems after years of process
development. A total of 5000 hours of experimental investigation was completed
in this device. Time-on-stream of the catalyst was
greater than 700 hours, the conversion of cyclohexanone oxime was greater than
99.9%, and the selectivity of caprolactam was greater than 96.5%. Meanwhile, the high quality ¦Å-caprolactam was
produced with crystallization refining in this pilot
plant.
At present, the process has already been industrialized and promoted.

3       
Conclusion

Vapor-phase Beckmann rearrangement process of
produced ¦Å-caprolactam was developed by RIPP-SINOPEC, which is a green process
and high atom economic. The technology has completed pilot plant verification and
will realize industrial production in recent years.