ASH SOFTENING POINT THE IMPACT OF ADDITIVES, A LAB SCALE STUDY SEWAGE SLUDGE COMBUSTION

Transcription

1 ASH SOFTENING POINT THE IMPACT OF ADDITIVES, A LAB SCALE STUDY SEWAGE SLUDGE COMBUSTION Fluidized Bed Combustion Dipl. Wirt. Ing Matthias Mann

2 Content I. Part Lab Study I. Definition of the Project II. Agglomeration Process III. Incineration process of biomass IV. Lap scale FBC/FBG V. Agglomeration detection VI. Results VII. IPV Process II. Part Sewage Sludge Combustion I. Küttner a short introduction II. Overview Küttner s Supply for Sewage Sludge Incineration Plants III. Bubbling Fluidized Bed Reactors Küttner Design for 1 or 2 stage combustion reactors IV. Küttner References Infraserv Gendorf Basic Design V. Küttner References Biomassenverwertung Großwilfersdorf 2 staged combustion, open base VI. Küttner References Asymmetric Reactor Design Bitterfeld VII. Sewage Sludge Incineration VIII.Sewage Sludge Incineration Next Steps 2

3 Definition of the Project Biomass fuel for an integrated pyrolysis and combustion Culm shaped Biomass: Triticale straw (residual product) as an fuel substitute Analysis of fuel with a low ash softening point Experimental study with a lab scale reactor, aims: Allow constant as well as high process temperature Minimization of the sintering and agglomeration tendencies No plant-specific changes Use of additives or other procedures Cost-efficient No changes for the operating procedure Moddeling and melt microscope data are not conform This project was developed during a PhD study The PhD study was supported by the DBU (Deutsche Bundesstiftung Umwelt) 3

4 Definition of the Project The new approach of this study is the use of fuel ashes instead of fuel Fuel is transcribed into ash by using a rotary kiln at a temperature of 550 C The ashing process is the basis for this research because it allows repeatable and constant conditions The fluidized bed reactor has a constant feed and is indirect heated The fluidized bed reactor is equipped with a plurality of measuring devices for an extensive impression of the process Different additives are evaluated Dolomite Calcite Kaolin Bauxite Feldspath Ferric trioxide Ilmenite MgO 4

5 Agglomeration Process Small particles 5

6 Incineration process of biomass Incineration Batch process conformity to CEN/TS Maximum temperature 550 C Long resting time (approx. 3 h) Controlled atmosphere No discharge of alkali by the gas phase Result Large quantity of useable ash Low residual carbon content 0,8 to 1,1 weight percent 6

7 Lab scale FBC/FBG 7

8 Agglomeration detection Defluidisation detection Process: Hot Spot detection Pressure trend detection 8 Reliable detection of agglomeration start

9 The agglomeration detection The diagram shows a process visualisation: The temperature variation during the fuel feed Rising of temperatures and unstable fluidization after 25 minutes 9

10 Results Trial matrix with 420 hot samples Each experimental series starts at 810 C Step size 10 K 10 Ash ratio in bed max. ~ 5 %

11 Results Results Process with ash instead of fuel leads to a high process quality Deviation from the melting microscope samples of the fusibility of fuel ash Lower deviation of sintering Increasing the sintering temperature by using Defluidisation temperatures (starved air condition) C additives is possible 11

12 IPV Process IPV Process Two strand design Fixed Bed Pyrolysis Reactor Fluidized Bed Combuston Reactor ( C) High calorific value process gas without nitrogen thinning Large fuel flexibility Dezentral power generation by gas engine etc. 12

13 Musterseite 3 BILD mit BILDUNTERSCHRIFT Part II 13

14 Küttner a short introduction KÜTTNER was founded in 1949 by Dr. Küttner and has ever since developed into a group of companies mainly working in plant engineering and construction. until 1960 until 1970 until 1980 until 1990 until 2000 until 2005 Handling with conveyor technique Construction of large charging systems for blast furnaces Introduction in Furnace Construction Internationalization Development of the Non Ferrous Technology Development of the Energy and Environmental Technology August Thyssen Metallurgical Plant, 1971/31 Blast furnace I, screening station for coke, sinter and iron ore 14

15 Küttner a short introduction INDUSTRIES Steel Mills Foundries Non-Ferrous Environmental Industry Energy generation TECHNOLOGIES Material Handling Industrial Furnaces Heat Recovery Systems Flue Gas Cleaning Systems Automation SERVICES Planning Design Delivery Construction Commissioning 15

16 Overview Küttner s Supply for Sewage Sludge Incineration Plants Feed Reactor Waste heat recovery Flue gas cleaning Ash removal Automation Thermal Power [kw th ] Decentralized Inhabitants Plants Sludge Quantity 20% DS [t/a] Thermal Power Output ,5-10 MW

17 Bubbling Fluidized Bed Reactors Küttner Design for 1 or 2 stage combustion reactors Closed base: Open base: Freeboard burner Material input Air from fluidized cooler Start-up burner Secondary air Recirculation of fine particles Ash and sand to fluidized cooler Material input Windbox burner Fluidization air Fluidized cooler Primary air Extraction of coarse particles Separation of coarse particles 17

18 Küttner References Infraserv Gendorf Basic Design SYSTEM FEATURES Capacity: t/a municipal, petrochemical and industrial sludges Inner diameter: 2,4 m and 4 m Total height: 9 m Bed temperature: 850 C Throughput: 1,5 t/h drained sewage sludge (50 % DS) Thermal power output: 3 MW Steam production: 3,5 t/h (20 bar) Gendorf, Germany sewage sludge incineration with steam generation 18

19 Küttner References Biomassenverwertung Großwilfersdorf 2 staged combustion, open base SYSTEM FEATURES Capacity: t/a various types of sludge Continuous ash extraction system Total height: 15 m 2-stage combustion Bed temperature: 820 C Freeboard temperature: 850 C Throughput: 2 t/h mixed sludge (48 % DS) Thermal power output: 2,4 MW Thermal oil boiler: Großwilfersdorf, Austria sewage sludge incineration with continuous ash extraction system and thermal oil boiler 2,2 MW 19

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21 Küttner References Asymmetric Reactor Design Bitterfeld SYSTEM FEATURES Capacity: t DS /a various types of sludge ash extraction system Total height: 20 m 2-stage combustion Bed temperature: 800 C After Burning Chamber 900 C Throughput: 4 t/h mixed sludge (50 % DS) Thermal power output: 4,7 MW Steam Boiler Air Pre Heating ~ 450 C C 21

22 Sewage Sludge Incineration Up to date solution: Sludge incineration ~ t/a Flue Gas Residuals Ash Energy for thermal sludge drying t/a 22

23 Sewage Sludge Incineration Next Steps ~ 100 kw el Sludge incineration ~ t/a II ORC Module DHW (70 C ) 700 kw 300 C I Flue Gas Residuals Air Pre Heating I II III Autothermal Incineration Power generation internal consumption Phosphor recovery, Minimization of disposal ~ 600 C Ash t/a for Integrated Phosphor Recovery III Fertilizer 23

24 Thank you for your attention! Dipl.-Wirt. -Ing. Matthias Mann -Head of Process Engenieering- Küttner Enegrgy & EnvironmentGmbH Alfredstr. 28, Essen 24