E deud energy efficient pulp mills buenos aires

Energy Efficient Pulp Mills

Looking Back and Forward

Eduardo Deud

Buenos Aires - Argentina June, 13th, 2016

Agenda

Energy efficiency in pulp and paper industry – Looking

Back;

Technology Evolution during the years;

The modern pulp mill. Where we are nowadays;

Future trends and challenges – Looking Forward.

21 June, 2016 © Valmet | Dimas Rodrigues2

Energy efficiency in pulp and paper industry

Looking Back

Energy efficiency in pulp and paper industryMacro Economy Scenario – Looking Back (some years ago)

Lower electricity prices. More predictable rain seasons and higher

hydroelectric power source contribution in the matrix;

Low international crude oil price. Lower wood and pulp logistic costs;

Lower contribution of the labor cost in pulp production cash cost;

Lower land/forest cost and lower specific cost per installed capacity

(USD/ADtB);

Lower China demand (less average discount on list market price);

Lower focus on the energy efficiency. “The pulp profit can pay every

inefficiency”

21 June, 2016 © Valmet | | Dimas Rodrigues4

Energy efficiency in pulp and paper industryLooking Back – Pulp and Paper mills in South America

Years 50 and 60

– Mostly integrated pulp and paper mills

– No surplus energy for sale (deficit)

– High volumes of heavy oil consumption to produce heat/steam

Years 70 and 80

– Integrated pulp and paper mills and some fully market pulp mills

– Some of the market pulp mills self sufficient on heat and electricity (but using bark as

an auxiliary fuel)

– High volumes of heavy oil consumption on integrated mills. Small of non consumption

in market pulp mills to produce process steam;

Years 90 and 00

– More investment in market pulp lines;

– Some surplus energy for sale, but without relevant impact in the financial result.

Forest debarked wood (trend);

Nowadays

– Almost all large scale investment in market pulp mills;

– Surplus energy is mandatory for the project feasibility.21 June, 20165

Energy efficiency in pulp and paper industryLooking Back – Characteristics of the plants

High specific steam consumption (kg/ADtB).

– Black liquor burning usually not sufficient to balance steam production demand.

– Auxiliary fuel is required (oil and/or natural gas).

– Woodyard debarked logs. Bark burned in a biomass boiler;

Many equipments installed and high specific power consumption

(KW/ADtB);

Small or non condensing turbine installed;

Power consumption > Power generation. No surplus power for sale.

Small scale pulp and paper mills.

21 June, 20166

Looking Back Mill size has been raised to keep the Cost/ADtB of installed capacity

21 June, 2016 © Valmet | Author / Title7

Economical Installed Capacity - New Bleaching Plants

AD

tB/y

Year


Technology Evolution


Woodhandling, white liquor plant and evaporation

– Power consumption has been reduced mainly due to more efficient motors, pumps

and simplifications;

Cooking and Fiber line

– Significant reduction caused specially by technology evolution and innovations;

Recovery boiler

– Increased the specific power consumption (KW/tDS) over time. High power features

demands more power consumption (more equipments);

Power consumption in cooling tower system has increased

– Higher condensing flow on the condensing turbines.

The average specific power consumption in a modern mull has

reduced dramatically during the years;

21 June, 20169

Energy efficiency in pulp and paper industryTechnology Evolution – Specific Power Consumption (KW/ADtB)

Energy efficiency in pulp and paper industryTechnology Evolution


Year

Specific Power Consumption - BEKP

KW

/AD

tB

Energy efficiency in pulp and paper industryTechnology Evolution – Cooking Plants Development


Energy efficiency in pulp and paper industryTechnology Evolution – Cooking Plants Development


2001 Nowadays

Energy efficiency in pulp and paper industryTechnology Evolution – Fiber Line Development


Bleaching Plant Main Equipments

Years 70 Present

Sequence 5 stages 3 stages

Towers 10 3

Washing 10 3

Mixers 20 3

Pulp Pumps 10 5

Screws 16 4

Centrifugal pumps 60 12

Heat Exchange 2 8

Electrical Motors 180 48

Control Valves 126 49

Pulp pipes 60 39

Tanks 24 11

Scrapers 8 4

Comparison Basis

550.000 ADtB/y bleaching plant

90% ISO Brightness

BEKP plants

Energy efficiency in pulp and paper industryTechnology Evolution – Fiber Line Development


LH

Focus on lower power consumption

Towers height optimization

Towers diameter enlargement

Direct feed to the presses

No MC pump required

Lower power consumption

High consistency presses feeding (8-9%)

High consistency presses discharge (32-34%)

Heat integration with cooking plant

Pulp Pumping


Specific steam consumption has reduce dramatically in all the areas

during the years, except in the Recovery Boiler;

The thermal integration inside the area and between areas have been

used;

Effluent temperature from bleaching plant has reduced and water

usage has been reduced as well;

Required pressures for LP and MP steam has reduced (Nowadays MP

is 8 kgf/cm² and LP is 3,5 kgf/cm² (g)). It contributes for the turbine

efficiency improvement during the years;

Recovery boiler has increased the consumption due High Power

Features concepts (heat circulation);

Demi water and turbine condensate have been heated up;

Condensing turbine flow has been increased during the years. Bigger

cooling towers have been required.

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Energy efficiency in pulp and paper industryTechnology Evolution – Specific Steam Consumption (kg/ADtB)

Energy efficiency in pulp and paper industryTechnology Evolution – Generation & Consumption - Steam

16 * w/o High Power Features

Energy efficiency in pulp and paper industryTechnology Evolution – Energy Efficient Cooking Plant - Concepts


Minimum Hot Water generation

No CNCG generation

Low DNCG temperature generation

Hot and pressurized transfer circulation

Economizers to heat white liquor

No washing added in the cooking zone

Good impregnation and

Low cooking temperature

Integration with Evaporation Plant

Minimum live steam added in weak liquor

< 400 kg steam/ADt

Energy efficiency in pulp and paper industryTechnology Evolution

21 June, 201618


Hot water balance and hot water generation have been optimized in

order to recovery waste energy from effluent. Hot water temperature

has increased;

Chlorine dioxide is usually heated up to 45°C nowadays;

White Water is hotter due hotter last bleaching stage;

Process condensate from evaporation plant utilized in the brown stock

washing has been heated up through the heat recovery from the weak

black liquor;

By heating the process condensate, the delignification steam

consumption is minimized;

Effluent streams (acid and alkaline) have heat exchange to recovery

the energy waste.

21 June, 201619

Energy efficiency in pulp and paper industryTechnology Evolution – Specific Steam Consumption (kg/ADtB)

Energy efficiency in pulp and paper industryTechnology Evolution – Effluent is a constant focus


Lower effluent flow and temperature are key factors to assure the lowest as possible steam consumption in the fiber line;

Energy efficiency in pulp and paper industryTechnology Evolution – Modern Pulp Drying


The key factor for a good Pulp Drying performance in terms of heat

consumption is the Wet End design;

Wider machines and lower basis weight assure better sheet dryness

before the dryer and consequently lower steam consumption;

A higher basis weight combined with a high machine speed (upper

limit) means a large dryer and as a result high steam consumption and

high power consumption;

The main opportunities for power consumption reduction in the pulp

drying area are in the screening room. Recent application has

demonstrated impressive power savings on recent projects.

Energy efficiency in pulp and paper industryTechnology Evolution – Modern Pulp Drying


Dryness in the Dryer feeding

Sheet Dryness vs Heat Consumtion in the Dryer – Pulp Drying Machine

He

at S

avin

gs

Modern and Efficient Wet End

Energy efficiency in pulp and paper industryLooking Back – Evaporation and Recovery Boilers in South America

Years 50 and 60

– Predominant boilers from 13 to 26 bar of steam pressure

– Low dry solids content from evaporation (55 ~ 65%) 4 or 5 effects predominantly

Years 70 and 80


– Dry solids content from evaporation typically (65 ~ 75%) 5 or 6 effects predominantly

Years 90 and 00


– Dry solids content from evaporation typically (70 ~ 75%) 6 effects predominantly

– Some ash treatment installed

– NCG and methanol in some installations

Nowadays


– Dry solids content from evaporation typically (80%) 6 or 7 effects

– High power features (partial or total)

– High heat rate in the furnace (> 3,5 MW/m²)

– Ash treatment mandatory

– NCG and methanol burning as standard


Energy efficiency in pulp and paper industryTechnology Evolution – Evaporation Plant


80 - 85% DS

Design to avoid plugging

Integrated stripper collumn

Hot Weak Liquor

SOG heat recovery

7# effect

Economy up to 7,0 t H2O/t LP steam

Energy efficiency in pulp and paper industryTechnology Evolution – Black Liquor dry solids to burn

21 June, 201625

Vakkilainen and Holm, 2000, Wallén et al., 2000

Energy efficiency in pulp and paper industryTechnology Evolution – Modern Recovery Boiler


Energy efficiency in pulp and paper industryThe Most Efficient Recovery Boiler ever designed


Energy efficiency in pulp and paper industryWhere we are? Nowadays – What can be observed.


Nowadays, for the recent mills the electricity is a second profitable

product. Consequently it’s very important for the business income;

Actually, the surplus power is already higher than the internal

consumption, in both, forest debarked and woodyard debarked logs

mill;

On site chemical plant has been attractive due electricity availability at

low cost;

The decision between forest debarked and woodyard debarked logs

depends specially from the forest average radium and land

topography;

Energy efficiency in pulp and paper industryPresent Technology - Internal consumption lower than the surplus

21 June, 201629

Forest Debarked Wood Woodyard Debarked Wood

BEKP 1.500 K ADtB/y


Looking Forward

Energy efficiency in pulp and paper industryLooking Forward – Fiber Line Trends

21 June, 201631

Even lower steam consumption in the cooking and bleaching areas.

Better integration between areas;

Lower effluent temperatures;

Lower effluent flow and less water usage, without performance

reduction;

Less and more efficient machines, pumps and electrical motors

Application of VFDs will be more intensive;

Lower pressure is steam distribution pipe rack;

Termocompressors application;

Better heat integration on white water, condensate, hot water and

effluent.

Enzime could give an extra energy saving? Could enzime impact on

ClO2 consumption, effluent COD generation, D.S to RB and so on;

Energy efficiency in pulp and paper industryLooking Forward – Pulp Drying trends

21 June, 201632

Better waste heat recovery from the dryer section in order to minimize

the usage of steam in false ceiling, building heating and dryer cooling

air heating;

More efficient dryers (Lower MWth/t H2O evaporated);

Lower power consumption in the screening room and more efficient

machines;

More efficient technology for the vacuum system;

Higher sheet dryness before the dryer (56 – 58%).

Energy efficiency in pulp and paper industryLooking Forward – Evaporation Trends

21 June, 201633

Additional integration with other areas, mainly cooking plant, demi

plant and recovery boiler areas;

7 effects concept;

83 to 85% dry solids;

Hot and pressurized weak liquor from digester as standard solution;

Better condensate quality requirements (low thermal efficiency

direction);

Evaporation of effluent sludge;

Lignin extraction to produce more valuable products;

Energy efficiency in pulp and paper industryLooking Forward – Recovery Boiler Trends

21 June, 201634

Higher steam parameters (pressure and temperature), supported by more

efficient ash treatment systems and advance in metallurgy (superheater

materials);

Feedwater regenerative cycle in two stages;

Re-Heating steam concept;

Low pressure Sootblowers type consolidation;

Integration with other areas to recovery waste heat;

Higher dry solids content in black liquor burning (85%);

Higher hearth heat release rate (HHRR) in MW/m²;

Maximum combustion air temperature as possible;

Wide range of fuels (black liquor, CNCG, methanol, effluent sludge);

Possible higher inorganic/organic ratio (due partial lignin extraction);

Application of some High Power Features in existent boilers

ConclusionsThe Energy Efficient pulp mill - Looking Back and Forward

Technology has been improved providing more efficient

equipment and solutions;

The specific steam and electricity consumptions in the BEKP

production has decreasing during the years;

The impact of the power generation revenue in the financial

result is increasing during the years. Nowadays the power

generation revenue is mandatory for the feasibility in new

projects;

Concepts and solutions applied in modern mills could (partially)

be implemented in existent mills with short pay back;

There is a huge potential on the power generation area

considering the tendencies.


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