Process of purifying exhaust gases produced by combustion of waste materials

US5575982A · kind A · utility

Assignee

• Metallgesellschaft AG · DE

Inventors

• Guenter Reiss · Oberursel, DE
• Georg Schaub · Oberursel, DE

Key dates

• Filing date: Dec 16, 1994
• Grant date: Nov 19, 1996
• Expiry date: Dec 16, 2014

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01D53/75
• WIPO field: Chemical engineering
• WIPO sector: Chemistry

Abstract

The process purifies exhaust gas produced by combustion of waste materials including garbage, industrial wastes and/or sewage sludge. The exhaust gas is contaminated particularly with dust, SO.sub.2, HCl, HF, Hg, mercury compounds, and dioxins and furans and can be expected to have an oxygen content. In the process, the exhaust gas is treated in a spray absorber with a suspension of Ca(OH).sub.2 ; the exhaust gas is subsequently filtered in two successive filteration stages; the exhaust gas leaving the first filtering stage still has an SO.sub.2 content of from 20 to 500 mg/sm.sup.3 ; activated carbon, preferably hearth furnace coke, is introduced into the exhaust gas stream before the second filtering stage; and the exhaust gas is finally scrubbed with a mixture which contains water and NaOH, Na.sub.2 CO.sub.3, Ca(OH).sub.2 and CaCO.sub.3 in a dissolved or suspended state.