VULCAN DiTOX Process - Catalytic Reformer Vent Gas Abatement
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The document outlines the vulcan ditox process and various methods for managing dioxin emissions, highlighting the challenges associated with dioxin formation, monitoring, and disposal. Various techniques for dioxin removal are evaluated, including fixed bed active carbon and alkaline semi-dry scrubbing, though none effectively eliminate chloride and all incur significant costs and regulatory challenges. The proposed solution emphasizes a method that prevents dioxin formation by removing precursors before cooling, utilizing proven absorbents to enhance efficiency and minimize health and disposal issues.
VULCAN DiTOX Process - Catalytic Reformer Vent Gas Abatement
- 1. VULCAN DiTOX Process By Gerard B Hawkins Managing Director
- 2. 78% N2 17% CO2 4% H2O 1% O2 1000 ppm HCl 20 ppm Cl2 trace organics Semi-regens and cyclic reformers have variable vent compositions , with peak chloride levels as above
- 3. Presence of Cl , O2, C source, particulates Temperatures between 930-480 F (500-250 C) Dioxin formation
- 4. TEQ < 0.1 ng/m3 (Europe) MACT II ? Limits on chloride emissions ?
- 5. 1. Fixed bed active carbon ◦ Cheap, simple ◦ Cost of dioxin contaminated carbon disposal ◦ No chloride removal 2. Alkaline semi-dry scrubbing ◦ Messy ◦ Dioxin contaminated product again 3. Fabric filters ( + catalysed destruction) ◦ No chloride removal ◦ Dioxin contaminated bags 4. H2O2 catalysed destruction ◦ Peroxide hazard ◦ No chloride removal 5. High temperature Catalytic destruction ◦ High capital cost ◦ No chloride removal
- 6. All these processes allow dioxins to form which are then removed ◦ Removal may not be complete ◦ Dioxin monitoring & analysis required Difficult Expensive ◦ Dioxin waste handling & disposal Highly regulated & controlled Difficult Expensive ◦ Dioxin contamination problems Plant & equipment contamination Maintenance procedures Personnel exposure & monitoring
- 7. Dioxins form as gases cool ◦ 250-450C (480-840F) Removal of dioxin pre-cursors at high temperature Prevents dioxin formation
- 8. Thin layer of high capacity alumina guard trap to catch particulates Bed of VGP CRT-2000 ◦ Removes HCl and Cl2 ◦ Operation at 930-990F (500-550 C) ◦ Proven absorbent Elimination of precursors to dioxin formation before cooling
- 9. O2-enriched air O2-depleted air combustion chloriding redispersion Regenerator VGP CRT 2000 Vent Burn-off loop Guard Trap[ Can be fixed bed or moving bed
- 10. Simple process Proven absorbents Prevents dioxin formation ◦ No plant contamination ◦ No disposal of contaminated materials ◦ No personnel health issues ◦ Minimises dioxin monitoring & analysis Also removes HCl, Cl2 & particulates Cost effective Easily retrofitted