Mercury in Cement Clinker Production - Behaviour and ...camara-alemana.org.pe/downloads/160622-8-Presentacion-Hg-Beilman… · Mercury in Cement Clinker Production - Behaviour and

Mercury in Cement Clinker Production -

Behaviour and Abatement of Emissions

June 21st, 2016 | Reinhard Beilmann | tkIS

Peru, 1st Conference – Determination and Abatement of Mercury Emissions

2 | June 21st, 2016 | Mercury in Cement Clinker Production | Reinhard Beilmann tkIS

Behaviour of heavy Metals in Cement Kilns

Volatility

Arsenic

Nickel

Chrome

Copper

Cobalt

Cadmium

Lead Thallium Mercury

non low light high

Emissions

solid, (bounded) bounded

and gaseous

Enrichment on filter dust (%)

0


Mercury – Emission Measurements at German Cement kilns

Limit: 30 μg/Nm³

Exceptional Limit: 50 μg/Nm³

if caused by Raw Material

Source: VDZ 2008

34 yearly averages from

continuous control and 112

measurements from

44 plants. 5 Values below detection

limit.

Measurement

Concentr

atio

n in m

g/N

m³


Mercury – Emission Measurements at US Cement kilns

Source:


Mercury Cycle in Cement Kilns – direct operation

Clinker

Dust Hg

Hg

Silo

Hg

Hg-Sources: Fuels + Raw Meal

Direct operation:

High mercury emissions

Adsorption on the dust (depends on the temperature)

Raw Meal

Fuels

Silo

Filter

Mercury evaporation from Raw Meal


Mercury Cycle in Cement Kilns – compound operation

Clinker

Hg

Hg

Silo

Hg

Hg-Sources: Fuels/Raw Materials/Meal

Compound operation:

Enrichment in the outer cycle (depending on mill type, amount of kiln gas used for grinding)

Lower mercury emissions

Raw Meal

Fuels

Raw Materials

Dust

Filter

Silo

Bypass


Mercury - Typical Emission Behavior

Compound Operation Compound Operation Direct

Operation

Stack

Source: tkIS


Reduce Mercury input into the System

Primary Mercury Abatement Technologies

Fuels:

could be possible

Raw Materials: might be possible if a minor component is the source but hardly achievable if the Limestone Quarry is the Source



Quecksilberabscheidung in Abhängigkeit

von der Gastemperatur

80 100 120 140 160 180 200 220 0

25

50

75

100

Gas Temperature in °C

Mercury Removal in %

Exhaust gas cooling as a Precondition

Dust shuttling (typically in direct operation)

Filter-dust

back to process

(Silo)

Filter-dust to

Clinker grinding or disposal



Effect of Dust shuttling in direct operation

Hg Emission without Dust Shuttling

compound operation

clean gas temperature cle

an

ga

s te

mp

era

ture

(°C

)

Hg

co

nce

ntr

atio

n c

lea

n g

as (

µg/N

m³)

Hg concentration clean gas

Hg Emission with Dust Shuttling in dircet operation

compound operation

clean gas temperature

cle

an

ga

s te

mp

era

ture

(°C

)

Hg

co

nce

ntr

atio

n c

lea

n g

as (

µg/N

m³)

Hg concentration clean gas

Source: ZKG 11 2001, 591-601


Secondary Mercury Abatement Technologies: ACI

Dust Shuttling with ACI (typically in Direct Operation)

Filter-dust

back to process

(Silo)

Filter-dust to

Clinker grinding or disposal

Activated Carbon - Injection

approx. 30-40mgAC/Am³ @3000tpd Clinker 12-15kg AC/h

approx. 10 t/h ; 0,15% C @3000tpd Clinker and 8%Dust related to Clinker


Expected Hg-Removal with ACI from Industrial Trials (Landreth and Hardtke ZKG 11 2012, 46-51)

1 lb/MMacf equal to approx. 16mg/Nm³


Removal efficiency generally confirmed by plant operations


ACI with two Baghouses

Filter-dust

back to process

(Silo)

landfill

recycling

…

Secondary Mercury Abatement Technology: ACI

• improved efficiency

• pure activated carbon

• high investment




ACI - Hg-Removal Experience with two Baghouses

Source: Mercury Reduction - The Plant Experience

Terry Kerby, IEEE 2016


Filter-dust

back to process

(Silo)

Hg-Desorption

Secondary Mercury Abatement Technology – ACI with

Hg-Desorption from Dust



Secondary Mercury Abatement Technology -

Thermal dust treatment for Hg-Desorption by TKIS

o Waste minimization: High Hg Enrichment factor

o Extremely compact design, mobile full scale

demonstration plant possible

Product

Product Heat

Exchanger

Feed

Cyclone

Reactor

Clean Gas ACF


Indirectly

heated Rotary kiln

for thermal Treatment

of EP-Dust

Industrial Installation in 1992

Secondary Mercury Abatement Technology -

Thermal dust treatment for Hg-Desorption by TKIS


Mercury Online Measurement

Big discussions about accuracy in cement process in Germany.

Very low concentration (µg/Nm³)

Alternating concentrations Different measurement ranges in compound and direct operation

Interferences (newer analyser with underground compensation)

Hg

HgCl2

Only detection of elemental mercury (photometer)

Ionic mercury hast to be converted to the elemental form

Older analysers uses a converter material → Deactivation by the sample gas of the kiln exhaust

Newer analysers: Thermal conversation


Conclusion Mercury in Cement Kilns

• Mercury is completly volatile in the preheater

• During mill down times (direct operation), the outer cycle is partly unloaded

• Dust Shuttling is the first step to reduce Mercury Emission

• Low temperatures in the filter are advantageous

• Activated Carbon Injection may further reduce Emissions

• Plant specific emissions and the maximum allowable emission determine the suitable

abatement technology

Mercury in Cement Clinker Production –

Behaviour and Abatement Strategies

Any questions?

Thank you for your attention!

Documents

Mercury in Cement Clinker Production - Behaviour and ...camara-alemana.org.pe/downloads/160622-8-Presentacion-Hg-Beilman… · Mercury in Cement Clinker Production - Behaviour and