Gasification of solid wastes by Gasification of solid wastes by means of a pilot scale fluidizedmeans of a pilot scale fluidized--

bed reactorbed reactorCampaniaCampania Science & Technology Week in BeijingScience & Technology Week in Beijing

China China MilleniumMillenium MonumentMonument , 18 , 18 -- 23 May 200723 May 2007

U. Arena and M.L. MastelloneRaffaele Cesaro

AMRA

2

Solid waste fatesSolid waste fates

0

10

20

30

40

50

60

70

80

90

100

EU

-25

Bel

gium

Den

mar

k

Ger

man

y

Gre

ece

Spa

in

Fran

ce

Ital

y

Net

herla

nds

Pol

and

Por

tuga

l

Finl

and

Sw

eden

Uni

ted

Kin

gdom

Was

te f

ract

ion,

%

Recycled Landfilled

Incinerated

3

Necessity of Alternatives to Necessity of Alternatives to Landfill and IncinerationLandfill and Incineration

LANDFILLLANDFILL with its many drawbacks is yet the preferred option in many, even industrialized, countries, even though there are several Statesthere are several States in Europe and Asia that are in heavy difficulties to find landfill sitesthat are in heavy difficulties to find landfill sites, due to the nature or the limited extension of their territory.

INCINERATIONINCINERATION is a possible, proven alternative but its dominating technology (the mass-burn grate combustion) has yet some drawbackshas yet some drawbacks, like low energy efficiencies, hazardous emissions and harmful final process residues.

4

Necessity of More Sustainable Waste Necessity of More Sustainable Waste Management TechniquesManagement Techniques

ECONOMICALLY AFFORDABLEECONOMICALLY AFFORDABLE

SOCIALLY ACCEPTABLESOCIALLY ACCEPTABLE

ENVIRONMENTALLY EFFECTIVEENVIRONMENTALLY EFFECTIVE

5

Economic SustainabilityEconomic SustainabilityGREATER VALUE RECOVERY FROM WASTEGREATER VALUE RECOVERY FROM WASTE

greater energy efficiencypotential polygeneration (energy and feedstock)valuable by-products

WIDER RANGE OF INVESTMENT ALTERNATIVESWIDER RANGE OF INVESTMENT ALTERNATIVESeconomical at smaller scaleat smaller scalepossibility to be optimized to specific waste streamspossibility to be optimized to specific waste streamspossible integration with Mechanical Biological Treatmentpossible integration with Mechanical Biological Treatment

FEEDSTOCK RECYCLINGFEEDSTOCK RECYCLINGvalue added products that can meet (even future) market

requirements

6

Social SustainabilitySocial Sustainability

NOT INCINERATION NOT INCINERATION (looking forward to reducing the NIMBY effect)

LESS VISUAL IMPACT LESS VISUAL IMPACT (smaller chimney)

EASIER PLANT ACCEPTANCE BY THE EASIER PLANT ACCEPTANCE BY THE INTERESTED PEOPLEINTERESTED PEOPLE

7

EnvironmentalEnvironmental SustainabilitySustainabilitySOLID WASTE AS A VALUABLE INDIGENEOUS SOLID WASTE AS A VALUABLE INDIGENEOUS

SOURCE OF FUELSOURCE OF FUELMSW and industrial wastes as a source of energy and

feedstockability to supplement fossil fuels in power generation and

other industrial processes

LESS SECONDARY WASTESLESS SECONDARY WASTESmore recyclable productsapproaching zero emissionzero emission process

8

• Offers both upstream and downstream advantages• Is capable of producing the ultra-clean synthesis gas

required for making multiple products (H2-rich gas)

• Produces an energy carrier• Generates non hazardous solid residues

Can Gasification Meet these Can Gasification Meet these Requirements?Requirements?

• GASIFICATION is the thermal process that involves the reaction of carbonaceous feedstocks with oxygen-containing reagents, usually air, oxygen, steam or carbon dioxide, generally at temperatures in excess of 800°C .

9

GasificationGasification vsvs CombustionCombustion

GASIFICATION

LHV GAS

4-6MJ/m3

MHV GAS

10-18MJ/m3 GAS TURBINE

SYNTHESIS

ENGINE

BOILER

SYNTHESIS

METHANOL

HYDROGEN

FUEL ALCOHOL

ELECTRICITY

PROCESS STEAM

AMMONIA

COMBUSTION FLUE GAS BOILER

CONVERSIONTECHNOLOGY

PROCESSING TECHNOLOGY

PRIMARY PRODUCTS

FINALPRODUCTS

STEAM &ELECTRICITY

10

WhyWhy gasificationgasification??Gasification offers both upstream and downstream

advantages.All carbon-based materials, (e.g. biomass, wastes, pulpersludge, natural gas) can be readily gasified after proper preparation to produce synthesis gas for subsequent production of energy and chemicals.

Gasification helps conserve valuable water resources Since, for instance, it uses approximately 30-40% less water to produce electric power from coal, compared to other coal-based generation technologies.

11

Gasification-based processes are the only advanced power generation technologies capable of producing the ultra-clean synthesis gas required for making multiple products.

The production of more than one product offers the unique opportunity to adjust to swings in market demand for products, while simultaneously maximizing the utilization of capital investment.

WhyWhy gasificationgasification??

Gasification produces an energy carrierFeedstock energy of the waste is transferred to the syngas, rather than all converted into thermal energy of flue gas. In this way it can be stored and used when and where it is more useful.

12

Gasification can reach high thermal efficiencies with competitive capital costs

On-going projects indicate that efficiencies between 45 and 50% will be reached within 2010 (with capital costs of about 800€/kWe) and between 50 and 60% within 2020 (with capital costs of about 700€/kWe).

Capital costs can range from 60 to 250€ per t/y installed (to be compared with a range 130-230 for incinerators)

Gate fee can range between 30 and 100€ per t/y installed (to be compared with a range 40-60 for incinerators with capacity larger than 200.000t/y).

WhyWhy gasificationgasification??

13

WasteWaste typetype suitablesuitable forfor gasificationgasification

14

Example of non hazardous solid residueExample of non hazardous solid residue

15

WhyWhy fluidizedfluidized bedsbeds??

• The rapid and good mixing of solids leads to almost uniform isothermal conditions throughout the reactor, so allowing a reliable process control.• The large thermal flywheel of well-mixed bed solids resists to rapid temperature changes and avoids formation of cold or hot spots.• The heat and mass transfer between gas and particles are higher than other gas-solid reactors. • The good quality of contact between gas and solids reactants increases their fractional conversions.•The possibility to apply the process on a relatively small scale makes wider the range of investment alternatives.

16

GasificationGasification todaytoday

17

FLUIDIZED BED FLUIDIZED BED GASIFICATION GASIFICATION ofofRDF and RDF and PACKAGING PACKAGING WASTESWASTES

The AMRA project The AMRA project

18

The AMRA project The AMRA project

PROJECT GOALSPROJECT GOALSinvestigation on type and quality of solid waste and

productseffect of injection of different reactants along the

freeboardsafety aspects for medium-small plants design and operating criteria for in-bed and over-bed

feedingimprovement of knowledge about economics for

companies interested to operate in solid waste disposal

19

The AMRA project The AMRA project

20

GASIFIER PARAMETERSGASIFIER PARAMETERS

Geometrical parameters:Geometrical parameters: ID: 381mm; total height: 6m; wall tickness: 12.7mm Capacity:Capacity: 30-60kg/hFeedstocksFeedstocks:: RDF, biomass, mixed plastics, pulperresiduesGasification agents:Gasification agents: air, steam, oxygen, nitrogen, carbon dioxideOperating temperature:Operating temperature: 700-950°CFlue gas treatments:Flue gas treatments: cyclone, scrubber, flareSafety systems:Safety systems: hydraulic guard, rupture disks, emergency nitrogen stream, safety valves, emergency bed material discharge, high- and low-pressure alarms

The AMRA project The AMRA project

21

FBG Control & ProtectionFBG Control & Protection

+/- 10°CTIC04SP = 800°C

Electric heaters voltage

Blast temperatureBlast temperature

+/- 10%Manual (based on a specific algorithm)SP = 25kg

Bed solids discharge Bed solids make-up

Pressure drop across the bed

Bed height

+/- 0.05Manual (based on a specific algorithm)

Fuel feed rateExit gas composition and flow rate

Equivalent ratio

+/- 20%FCV01-05SP=100 Nm3

(overall)

Flow rate of each gas reactant

Feeding gas flow rate

Fluidizing velocity

+/- 10°CTIC11-15-33-34 SP=850°C

Electric heaters voltage

Reactor temperature

Reactor temperature

Control Control rangerange

Controller Controller Adjusted variableAdjusted variableMeasured variableMeasured variableControlled Controlled variablevariable

22

First results: Control & First results: Control & ProtectionProtection

Run shut down for P>PAH09

PAH9=0.6bargPT03PI10PAH09

Cyclone pressure

Run shut down for Q>FAH01 orQ<FAL01for air and similar for other reactants.

FAH01=1.2SP01FAL01=0.8SP01for air and similar for other reactants.

FCV01-02-03-04-05FT01-02-03-04-05FI01-02-03-04-05FAH01-02-03-04-05FAL01-02-03-04-05

Feeding flow rates:(air, O2, CO2, N2, H2O)

Acoustic/visual alarm for P>PAH01Run shut down for P>PAHH01

PAH01=0.6bargPAHH01=1.2barg

PT02PI08PAH01PAHH01

Reactor pressure

Electric heaters HEAT03-04-05-06 shut down for T>TAHRun shut down if T>TAH for more than 5min

TAH13=875°C TE20-21-22-23 (lowest flange)TT20-21-22-23(highest flange)TIC20-21-22-23TAH13-14-15-16 (sec. blast inlet)

Wall reactor temperature

Electric heaters HEAT03-04-05-06 shut down for T>TAHRun shut down if T>TAH for more than 5min

TAH07=875°C TE11-15-33-34TT11-15-33-34TIC11-15-33-34TAH07-10-24-25 for HEAT03-04-05-06

Reactor temperature

ActionActionAlarm set point Alarm set point Instruments Instruments Protected variableProtected variable

23

FailureFailure in in blastblast flowflow raterate

Apparatus damage.

mechanical breakage of equipments

oxygen in the exit gas

explosion in the cyclone

Run stop.Gas release

into the atmosphere.

rupture disc RD01

explosion in the cyclone

very bad G-S contact due to

large by-pass of blast gases

oxygen in the exit gas

oxygen in the exit gasslugging regime transition

very bad G-S contact due to

large by-pass of blast gases

Run stopwater seal

very bad G-S contact due to large by-pass of

blast gases

high fluidizing velocity at the reactor bottom

slugging regime transition

PI20slugging regime transition

high flow rate in line 14

high fluidizing velocity at the reactor bottom

human error FAH01high fluidizing velocity at the reactor bottom

failure of FCV01

HIGH FLOW RATE in line 14

TOP TOP EVENTEVENT

AUT. PROT. AUT. PROT. MEANSMEANSWARNINGSWARNINGSCONSEQUENCESCONSEQUENCESCAUSESCAUSESDEVIATIONDEVIATION

24

FailureFailure in in blastblast flowflow raterate

Apparatusdamage.

mechanical breakage of the equipments

plugging along line 63

overpressure in lines and equipments

overpressure in lines and equipments

high tar content in producer gasplugging along line 63

Run stop.Gas release.

rupture disc RD01plugging along line 63

variation in yield and selectivity of gas products

high tar content in producer gas

high tar content in producer gas

operation with a lower ER

variation in yield and selectivity of gas

products

variation in yield and selectivity of gas

products

low fluidizing velocity at the reactor bottomoperation at lower ER

operation at lower ERLow flow rate in line 14

low fluidizing velocity at the reactor bottom

human error FAL01low fluidizing velocity at

the reactor bottom

failure of FCV01LOW FLOW RATE in line 14

TOP EVENTTOP EVENTAUT. PROT. AUT. PROT.

MEANSMEANSCONSEQUENCESCONSEQUENCESCAUSESCAUSESDEVIATIONDEVIATION

25

ConclusionsConclusionsFluidized bed gasification may offer a real alternative to Fluidized bed gasification may offer a real alternative to incinerationincineration, as it can be deduced by the novel treatment plants that are already operating for waste management. The reason can be found in: • greater flexibility to process specific wastesgreater flexibility to process specific wastes•• less secondary wastes and more recyclable productsless secondary wastes and more recyclable products•• greater energy efficiencygreater energy efficiency•• possibility to apply the process at smaller scalepossibility to apply the process at smaller scale•• possibility of material recycling to chemicalspossibility of material recycling to chemicals

26

ConclusionsConclusionsOn the other hand, there is the disadvantage due to the the disadvantage due to the risk of a less proven technologyrisk of a less proven technology, particularly taking in mind the heterogeneous nature of feeds like MSW. Today the main technical challenges are related to obtain: • higher power production efficiencyhigher power production efficiency•• improved improved syngassyngas cleaning cleaning to meet defined specification•• ability to produce a vitrified slagability to produce a vitrified slagTherefore the economics are far away from clearthe economics are far away from clear, and only in the next future the market will indicate which technology has the most effective approach.

27

The pilot plant BFBG of AMRAThe pilot plant BFBG of AMRA has been equipped with several protection and control devices and automations.

A recursive operability analysis was carried out during A recursive operability analysis was carried out during the design and construction stages and used to the design and construction stages and used to individuate the areas where more or different safety individuate the areas where more or different safety tools had to be installed.tools had to be installed.

We are working on: A better understanding of hydrodynamics of the fluidized bed reactor as well as of the thermodynamics of gasification process.

ConclusionsConclusions

28

Thank You very much for Your Thank You very much for Your attentionattention