Mercury removal in utility wet scrubber using a chelating agent
US6328939A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 31, 1999 |
| Grant date | Dec 11, 2001 |
| Priority date | — |
| Expiry date | Mar 31, 2019 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB01D53/64
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A method for capturing and reducing the mercury content of an industrial flue gas such as that produced in the combustion of a fossil fuel or solid waste adds a chelating agent, such as ethylenediaminetetraacetic acid (EDTA) or other similar compounds like HEDTA, DTPA and/or NTA, to the flue gas being scrubbed in a wet scrubber used in the industrial process. The chelating agent prevents the reduction of oxidized mercury to elemental mercury, thereby increasing the mercury removal efficiency of the wet scrubber. Exemplary tests on inlet and outlet mercury concentration in an industrial flue gas were performed without and with EDTA addition. Without EDTA, mercury removal totaled 42%. With EDTA, mercury removal increased to 71%. The invention may be readily adapted to known wet scrubber systems and it specifically provides for the removal of unwanted mercury both by supplying S.sup.2- ions to convert Hg.sup.2+ ions into mercuric sulfide (HgS) and by supplying a chelating agent to sequester other ions, including but not limited to Fe.sup.2+ ions, which could otherwise induce the unwanted reduction of Hg.sup.2+ to the form, Hg.sup.0.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.