Boiler Technology for Biomass Residues

ERK Eckrohrkessel GmbHAlexis Hellwig, Commercial Director

Conference of the AHK Germany, VietnamBioenergy in VietnamSeptember 16, 2013

Background of EckrohrkesselHistory and references

Eckrohr boiler technology was developed in the mid 1940s

first licensees started to build Eckrohr-boilers worldwide; ERK offers engineering only

outsourcing of the ERK technology from La Mont Kessel GmbH in 1977

today more than 30 licensees worldwide (from small boiler manufacturers to turn-key suppliers for example in Thailand BIB, Getabec and DGA)

>5.900 boiler and heater references with thermal outputs of 0.3-250MWth all over the world

references for biomass (>450), waste (>580), cogeneration (>200), fuel mixtures (>350) as well as coal, oil and gas (>4,000)

Background of Eckrohrkessel

Licensees all over the world (currently 31)

Energy From BiomassConversion technologies

fuels

gasificationcombustion (grate and fluidised bed)

ERK has references for all aforementioned conversion technologies choice of firing system depends on fuel quality, process and efficiency

requirements as well as commercial constraints

Energy From BiomassTarget of efficient combustion

1.) total burnout of fuel no carbon content in the ash no CO or pyrolytic gases in the flue gas

for higher efficiency and environment

2.) low NOx emission in flue gases, less effort for secondary DeNOx treatment

for the environment

3.) low dust content in flue gases less fouling and corrosion in the boiler

for a higher availability of the boiler

Grate System With Boiler

secondary air

secondaryair

slagging

meltic eutecticwith corrosion

superheater

evaporator economiser

high temperature corrosion

fine dust

Boiler Weight

Grate System With Boiler

Advantages:• very low demands to fuel treatment

Disadvantages:• cooled mechanical grate for higher calorific values

(higher plant and operation costs) ( scuffing of grate bars)• smooth packed bed hard to ensure• areas with cold streaks with CO and high dust loads• higher central excess air for sufficient burnout

→ boiler and flue gas treatment unit larger due to type of incineration (excess air)

Types of Gas Generators

Energy From BiomassGasification – Two Stage Combustion

Principle: generation of carbon monoxide and hydrogen under

sub-stoichiometric conditions in the first stage (gasifier) high temperature combustion in the second stage (torsional

chamber) low gasification temperatures keep complicated fuels, e.g.

chlorine and potassium, in the ash, thus reducing fouling and corrosion

Advantages higher steam parameters due to absence of complicated

substances; higher plant efficiency reduced maintenance & small plant components low investment and complexity

Disadvantages not proven for highly contaminated wood waste yet no existing references larger 70 MWth yet

Direct Relation of Two Systems

fuel

air for drying

air for gasifyingand pyrolysis

air for carbon burnout in ash

ashcooling

fuel

gases to burner controlled burnout

air

air pre-heating

air for carbon burnout

air for degasify-ing and pyrolysis

air for drying

0

200

400

600

800

1000

1200

1400

1600

1800

tem

pera

ture

in °

C

ash

CO streak low temperature

CO streak low temperature

NOxhigh temperature combustion

high ash heat loss

excess air: 1,4 excess air: ~ 0,5 excess air: 1,2

low dustcontentcool

ashes

DeNOx

high velocitywith high dust content (alkaline metals: Na, K)

alkaline condensation (Na, K)

air gasifier hight

Advantages of Counter Current Flow Gasification

1) Spatial separation of drying and gasification from the combustion process leads to uniform flue gas burnout.

2) Little excess air (20 %) in the subsequent combustion system leads to a smaller boiler (~25 %) and a smaller flue gas treatment unit.

3) Simpler and more robust gasification reactor less prone to interference4) Little loss of fuel due to extremely low carbon levels in the ash and cold ash

removal5) Concentration of nitrous oxide in the flue gas at a minimum even at a high

concentration in the fuel due to low gasification temperature6) Low levels of dust and contaminants, since the gasifier‘s fixed bed serves as a

filter in the counter flow→ higher efficiency factor for the entire plant, since the boiler runs with higher

steam parameters at low facility costs

Energy From Biomass

Gasification references

MWth 5 130

>100 references for biomass gasification plants (1-70MWth) Simple scale-up to 40MWel >40MWel plants possible, but unusual for biomass; gasifier adaptation

necessary

25 40 70

Gasifying Plant With Eckrohrkessel Boiler

40 MW Gasifying Plant Villacanas

Contact

Prof. Dr.-Ing. Udo Hellwig, General Manager p: +49 30 8977 46-0 e: uhellwig@eckrohrkessel.com

Alexis Hellwig (M.A.), Commercial Director p: +49 30 8977 46-0 e: ahellwig@eckrohrkessel.com

Address: Am Treptower Park 28-30 Schuckert-Höfe, Haus A 12435 Berlin Germany www.eckrohrkessel.com