Method and apparatus for the purification of vinyl aromatic compounds
US6348136B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 29, 2000 |
| Grant date | Feb 19, 2002 |
| Priority date | — |
| Expiry date | Feb 29, 2020 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S203/09
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
The present invention is directed to an apparatus and method for the distillation of a readily polymerizable vinyl aromatic compound employing a polymerization inhibitor. The vinyl aromatic compound is subjected to distillation in at least one fractionation column having at least one reboiler for maintaining the bottoms of said column at a proper temperature. The reboiler includes a heating section and a vapor phase section. The bottoms fraction from the fractionation column is cycled to the reboiler and subjected to heat to vaporize at least a portion of the bottoms fraction to form a vapor phase in the vapor section, A slip stream of the bottoms fraction is introduced to the vapor phase section of the reboiler. The slipstream contains polymerization inhibitor that had been added to the process at the fractionation column. The invention reduces fouling at the reboilers. The slipstream is optionally introduced to the reboiler using one or more spray nozzles. The polymerization inhibitor is added to the fractionation column in sufficient amounts to maintain a concentration of at least 400 parts per million by weight in the bottoms fraction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.