verein der zuckerindustrie innovative examples of energy efficiency in the german sugar industry -...

VEREIN DER ZUCKERINDUSTRIE

Innovative examples of energy efficiency in the German sugar industry

- dewatering and drying process for sugar beet pulp -

Energy Efficiency in IPPC installations, 21.-22. October 2004 in Vienna

Austria Trend Parkhotel Schönbrunn

Dipl.-Ing. Christian Voß

Südzucker AG for the GermanSüdzucker AG for the German Association of Sugar IndustryAssociation of Sugar Industry

Werk Warburg, D-34414 WarburgTel. 05641/ 9413

[email protected]

UU MWELT BB UNDES

AA MT, Berlin

Postfach 33 00 22, D-14191 BerlinTel. 030/ 8903-2829

[email protected]

Dr.- Ing. Joachim Wieting


1. Introduction (targets and development of the

specific energy requirement) 2. Mechanical dewatering process for sugar beet pulps in the sugar industry as regards energy 3. Drying processes (drum drying, low temperature drying and evaporation drying) 4. Energy aspects of pulp drying 5. Comparison of energy consumption and the economics of different types of installations with examples 6. Characterisation of the technology – economic and ecological aspects

Structure


The EU Commission is supporting the

implementation of the directive as part of

its exchange of information by having

leaflets compiled on the „best available

techniques (BAT)“ by the European

Integrated Pollution Prevention and

Control (IPPC) Bureau in Sevilla,

Spain.

Background and Motivation

With the finalisation of the Council Directive 96/61/EC concerning „Integrated pollution prevention and control“, the so-called „IPPC Directive“, the concept of an integrated approach to reduce environmental pollution is being pursued at European Community level for the first time, with all installations covered by the directive now requiring permits.


• The efficient use of energy in the industry

helps avoid and/or control emissions in the

air, in water and in the ground as far as

possible.

•The formulation of the directive into a new

VDI guideline in Germany will set out

primary and secondary control measures

and new reduced emission figures for

production technology.

Background and Motivation

• The „food, drink and milk“ BREF gives information at community level on the best available techniques in the sugar industry to help promote the use of these techniques and to support the member countries effectively in their efforts to protect the environment.


Introduction precautions in the interest of the climate

Agreement between German sugar industry and the government board signed on 19.12.2000:

Reduction of the specific CO2 emissions of 41 – 45 % by 2005/06 Base year 1990: CO2 emissions/beet 148 kg/t

Target year 2005/06: 81 – 87 kg/t

achieved 2000/01: 84 kg/twith 288.5 kWh/ton of beet

Target achievement: almost 100 %


Introduction Specific energy consumption in the

German sugar industry

kWh /100 kg beets

0

25

50

75

100

125

1950 1960 1970 1980 1990 2000 2010year

ABL

DDR / NBL

D, ges basis 1990:

35,6

current 1996:30,6

target 2005 :29

ABL = old Federal statesNBL = new Federal statesD = Germany as a whole


Introduction Specific energy consumption in the

German sugar industry

Since 1990 > 300 Million € have been invested in projects for combined heat and power generation (CHP).

Degree of efficiency of heat and power combinations > 90 %

re-use of the heat several times normalf = 7 – 8

Future:physical limits

increasing technical expenditure (costs)

marginal energy savings

______________________________________________________

Personal remarks on sugar market regulation


Introduction Energy conversion in a beet sugar factory

and VDI extra edition 2594

Main flows of energy and technical processes are more closely interlinked than in any other sector of industry.

Amount of energy usedSugar production : Dried pulp production

2 : 1

VDI-Guideline 2594 „Emission reduction in pulp drying plants in the sugar industry“, First printed August 2004

VEREIN DER ZUCKERINDUSTRIEEnergy aspects

of the dewatering process for beet cossettes

Production of dried pulp with 90 % dry substance and 10 % water from extracted cossettes with 10 (- 14) % dry substance and 90 % water

in 2 dewatering stages: mechanical thermal

Amount of energy usedkWh/t water approx. 30 approx. 3.000

1 : 100

Target: To remove as much water as possible mechanically.


Energy aspects of the dewatering process for beet cossettes

State of the art: Spindle presses horizontal/vertical

pulp inlet screen

ring, axially relocatable for pressing pressure variation

press water collector

pulp outlet


of dewatering process for beet cossettes

Quantity of material pressed out depends on capacity of presses - Hardening with calcium ions (gypsum), Development by Südzucker (SZ):

SZ-Pressing target before drying: 32.5 % dry substance in the pressed pulp

20

22

24

26

28

30

32

34

80 82 84 86 88 90 92 94 96 98 00 02

Campaign

Dry

-su

bst

ance

co

nte

nt

inP

ress

-pu

lps

in %

2

2,2

2,4

2,6

2,8

3

3,2

3,4

Wat

er c

arry

ing

in

kg

Wat

er/

kg D

ry-s

ub

stan

ce c

on

ten

t

Dry-substance content in % Watercarying in kg Water/kg Dry-substance content



Other mechanical dewatering processes % dry substance in the pressed pulp

• Diffusive dewatering: 65 in combination with evaporation plant to concentrate the press water Disadvantage: no suitable separation of solids/liquids

• High-pressure, multi-layer pressing: 50 Filter band press: 300 bar; 15 min. pressing time Disadvantage: no suitable filter cloth quality

no reliable control of the 300 hydraulic control loops

• Extraction under alkaline conditions 45 – 50 Pilot installations in France, Germany and England



Combination of electroporation and alkaline extraction

• Alkaline extraction results in increased deposits of calcium ions and thus to a definite increase in the pressability of the extracted cossettes - Dry substance (DS) content of extracted cossettes : 40 - 45 % (an increase of approx. 10 % DS)• Opening the cells by electroporation to prepare for deposit of calcium ions - opening the cell membranes by high voltage impulses

• high voltage impulses: a voltage of several hundred kV for the duration of approx. 1 µsec

• low energy demand: approx. 1 kWh/t beet


Energy aspects of dewatering process for beet cossettes

Changes in the mechanical properties of beet due to electroporation

• Electroporation increases the flexibility of the cossettes considerably and enables them to stand up to heavier mechanical stress.



mash

lime

electroporatedbeets

slicing machine

juice towards juice purification

electroporated and alkalined cossettes

Possible configuration of electroporation and extraction*

electroporation

beets

*patent applied for


Drying process

Steam system of a sugar factory with steam drying

85 -25

25 -3

Steam turbine Generator

Gas turbine Boiler 4,5 MW 14,7 MW

85 bar

3 bar

3 bar

3,3 bar

VT 1 VT 2 DU 1 DU 3

VD 1

VD 2-7

Start-up line 1,5 bar

DU 2

25 bar

Generator

Heating oil


Drying process

Steam system of a sugar factory with steam drying

Legend:

1 Cossette feed screw in cell 1

2 Stationary guide vanes

3 Cylinder with cyclone effect

4 Cyclone over cell 16 for separating entrained cossettes

5 Steam inlet into cyclone

6 Stationary guide vanes for steam return

7 Superheater for secondary steam

8 Blower fan for creating fluidised bed

9 Generated steam exit

10 Feed screw for cossette output from cell 16


.

Energy aspects of cossettes drying

In order to consider the energy aspects of the installations described, the general data of the factories with both direct and indirect dewatering systems have been standardised as follows: Beet processing 10.000 tons/day Length of „campaign“ (season) 90 days p.a. Mass flow of pressed pulp: 160 kg/t beet processed = 66,7 tons/h Dry substance content of the pressed pulp 31 % Dry substance content of the dried pulp 90 % Steam consumption of a sugar factory for 200 kg/t processed beet = 83.4 t/h Live steam pressure 85 bar Live steam temperature 525 °C Thermal value of the fuel 40.195 kJ/kg


.

Energy aspects of cossettes drying

Electrical energy demand of the sugar factory without drying 10.4 MW = 24.96 kWh/t beet processed Complete crystallisation of the thick juice in the beet campaignThese norms pre-suppose that the factories have the following technical installations: A steam generator with 85 bar and 525 °C. A corresponding back pressure turbine 3 bar back pressure to supply the evaporation station or 3 bar back pressure and 25 bar extraction pressure to supply the steam dryer. A gas turbine to reduce the use of electric energy when using a steam dryer.effluent treatment plant which can process the condensed vapours from the evaporation dryer.


Summary of the examples of installations

Steam dryer

High temperature dryer

Low/high temperature dryer

Factory without a dryer

Total electric energy demand

MW 11.55 11.20 12.10 10.40

Total fuel energy MW 73.72 111.83 104.80 67.13

Total electric energy obtained

MW 11.48 11.66 11.66 11.66

Total energy costs €/h 1,182 1,780 1,695 1,048

Total energy costs per campaign

103

€/a2,532 3,845 3,661 2,264



Additional energy costs in comparison to a factory without dryers for the individual variations:

• High temperature dryers 1.581 103 €

• Low/high temperature dryers 1.397 103 €

• Steam dryers 268 103 €

Operation related costs (higher investment costs of installations

in comparison to lower fuel costs in operation) • High temperature dryers 388 103 € p.a. • Low/high temperature dryers 460 103 €

p.a.

• Steam dryers 554 103 € p.a.



Investment costs plus net running costs of the dryer for the individual variations:

• High temperature dryers 38.4 Mio. €

• Low/high temperature dryers 40.7 Mio. €

• Steam dryer 40.9 Mio. €

Characterisation of the technology:At the present time steam drying is the best available technique for new sugar factory construction or for complete reconstruction of energy production and heat control systems. However, it cannot be integrated easily into a normal existing factory.


Advantages achieved by steam drying

Main achievement - Improvements for the environment with regard to emissions and energy consumption:

• Emissions are avoided by direct primary use of energy for drying.

• No application of steam-volatile and odorous vapours.

• Energy consumption 30% less than in a factory with direct drying.

Inter-media effects• Transfer of the exhaust fumes into the effluent (approx. 1.200 m3

effluent with a chemical oxygen requirement of 1.500 mg/l and a NH4-content of 25 mg/l).


THANK YOUIn conclusion we should like to thank all those who

participated -

the members of the VDI working group 2594,

the participating companies in the Sugar Association

and all of you for your attention.

THANK YOU

verein der zuckerindustrie innovative examples of energy efficiency in the german sugar industry -...

Documents

german sugar industry

sugar beet pulps

specific energy requirement

energy aspects of pulp

efficient use of energy

german sdzucker ag

socalled ippc directive

ippc installations