VULCAN DiTOX Process

By Gerard B Hawkins Managing Director

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

Presence of Cl , O2, C source, particulates Temperatures between 930-480 F (500-250 C)

Dioxin formation

TEQ < 0.1 ng/m3 (Europe) MACT II ? Limits on chloride emissions ?

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

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

Dioxins form as gases cool ◦ 250-450C (480-840F)

Removal of dioxin pre-cursors at high temperature

Prevents dioxin formation

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

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

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