energy management and debottlenecking of pulp and paper

Energy Management and Debottlenecking of Pulp and Paper Processes

Copie et redistribution interdites. | Copying and redistribution prohibited.

PACWEST ANNUAL CONFERENCEMay 2021

Enrique Mateos Espejel, Bahador Bakhtiari, Hakim Ghezzaz, Luciana Savulescu, Tatiana Rafione, Kurt Woytiuk

© 2021 FPInnovations/NRCan-CanmetENERGY. All rights reserved. Copying and redistribution prohibited. ® FPInnovations, its marks and logos are trademarks of FPInnovations.2

• Objectives and approach

• Methodology

• Application

– Key challenges

– Debottlenecking strategy

– Implementation pathways for debottlenecking

• Conclusions

Agenda


FPInnovations – CanmetENERGYResearch Collaboration

• Global vision

• Consolidated innovative approach

• Unique capabilities and tools from FPI/CanmetENERGY

– FPInnovations: know-how and understanding of product quality and operability impacts

– CanmetENERGY: utility and process optimization tools and process integration and process debottlenecking know-how

• Assessment of cross-effects between projects and departments

• Strategic engagement for supporting the forest industry

CanmetENERGY & CFS

FPI

Your Mill

3


Process Debottlenecking

Objectives:

• Identify and address the critical/true bottlenecks for cost-effective implementation of new

business models

Increase Overall Competitiveness

• Obtain significant value through effective

debottlenecking at low cost even before any high

investment changes are made

Approach:

• A systematic diagnostic approach was developed

to identify, quantify, and classify process

bottlenecks at the departmental and mill-wide

levels


Optimizing Mill Existing Assets

• Typical bottlenecks in pulp

and paper mills

– 65% of recovery boiler– 50% of pulp machines

dryers – Most digesters – Effluent systems – Power boiler - especially

when there is a condensing turbine

Operating over equipment design capacity increases the operating cost and

affects reliability

LIGNIN EXTRACTION

UTILITY SYSTEM

KRAFT PROCESS

RESSOURCES INTEGRATION

Chemicals

Water

Energy

BIOREFINERY TECHNOLOGY


Debottlenecking Approach

Energy System

Management

Step 1

• Defining the Priorities and Setting Targets• Establish the scope

Step 2

• Identify, Screen and Rank Bottlenecks• Quantify local and mill-wide bottlenecks

Step 3

• Process Performance Diagnosis• Global analysis and system interactions on bottlenecks

Step 4

• Establish Improvement Solutions• System optimization debottlenecking roadmap


Data Analysis

A systematic approach is adopted to identify and rank process bottlenecks.

Bottleneck RankingGlobal Perspective

Identify, Screen and Rank Bottlenecks

EXPLORE

Multivariate analysisProcess Knowledge

Equipment Design Specifications


Performance Indicators Root-Cause AnalysisGlobal KPIs Unit Mill Value

Expected Target

Potential Savings

Specific Total Energy Consumption GJ/MDt 23.5 19.8 16%

Specific Total Process Thermal Energy Consumption

GJ/MDt 15.1 13.1 13%

Specific Total Thermal Energy Consumption

GJ/MDt 19.2 16.1 16%

Specific Total Power Consumption kWh/MDt 913 830 9%

Specific Total Water Consumption m3/MDt 50 26 48%

QualityAvailability Performance

Identify proper debottlenecking sequence such that each step is towards an effective and

sustainable debottlenecking solution.

Process Performance Diagnosis


Establish Improvement Solutions

Selection of projects and prioritization

• System interactions are addressed through

models and simulation

• Production capacity increase

• Operating cost: energy, water, chemicals

• Environmental impact: water, GHG

• Capital costs


Application on a kraft Mill

• The primary objective was to help the mill identify debottleneckingmeasures to increase the production by 10%

• As a secondary objective, the study was to identify and prioritizeprojects suitable for establishing a five-year capital plan


Bottleneck Ranking Diagram

Equivalent Department Production vs Target and Current Production

0

200

400

600

800

1000

1200

1400

1600

CurrentProduction

RecoveryBoilers

Bleaching Evaporators BSW PulpMachine

EffluentTreatment

Kilns Cooking TargetedProduction

Bottleneck Ranking Diagram (BRD)Eq

uiv

alen

t P

rod

uct

ion

(t/

d)


I. Debottlenecking recovery boiler

• High steam variability caused by instability in the strong black liquor solids concentration

• Significant dead load in the chemical recovery loop

• Variable wood mix & different pulp grade productions

II. Improve evaporator performance & operation stability

• Low vacuum conditions & under performing due to leaks

• Limited capacity due to fouling

• Sub-optimal management of the weak black liquor inventory

III. Optimize causticizing efficiency

• Opportunity to improve control of causticizing

• Low residence time

Key Challenges (1)


IV. Reduce operating costs

• High chemical consumption

• Limited recovery of waste heat

V. Equipment availability

• Evaporation train not used at full capacity

• Occasional partial capacity utilization of some equipment

Key Challenges (2)


• Two main strategies for pulp production increase are considered

1. Prioritize debottlenecking the RB, Evaporators & Concentrators. These are the critical &limiting equipment for higher pulp production (stabilise RB load by reducing variability ofstrong black liquor solids concentration)

2. Increase cooking performance/yield (lower the amount of dissolved solids sent to the recoverycycle)

• Three types of projects are proposed for the purposes of debottlenecking:

1. Operational improvements (no/low Capex)

2. Retrofit projects (medium Capex)

3. Process upgrades/modifications (high Capex)

• Several cost reduction projects are also proposed

Debottlenecking Strategy


Evaporator Retrofit &

Recovery Boiler Upgrade

Process Transformation

Lignin Extraction

Tall oil extraction&

Recovery Boiler Upgrade

Wood room Cooking Retrofit Improvements

Recaust Upgrade &

Chemical Recovery loop optimization

BSW retrofit Pulp Machine Optimisation

Evaporator Operational

Improvements& BSW

optimisation

Recaust & Wood Room

Operational Improvements

Debottlenecking by Optimizing Existing Assets

6% DB

Further Debottlenecking Alternatives: Retrofit/Upgrade/Modification

Short term (1-2 years) - Low Capex

AVP: Added value product

Long term - High Capex

Evaporator Upgrade

10% DB

> 10% DB

AVP

Implementation Pathways for Debottlenecking

DB: Debottlenecking


Low cost/ Short Term

High cost/ Long Term

Capital Cost/Timeline (Qualitative)

Deb

ott

len

ecki

ng

Imp

act

(Qu

alit

ativ

e)

Low

P

ote

nti

alH

igh

P

ote

nti

al

EC11 – Increase steam pressure to evaps

EC2 – Adjust ejector, improve vacuum

CA1– Improve causticizing control -filter performance

WRC1 – Improve chips screening

BSW1,2 – Stabilize dilution factor & BSW performance

EC10 – Optimize splitting ratio of WBL

EC5 – Add ash to SBL instead of WBL

EC7 – Identify & fix vacuum leaks

EC4 – Evaluate BL comp, sesquisulphate

WCR2, 4, 8 - Optimize cooking performance

EC1,9 – Install external pre-heater, a 3rd heater

EC8 – Convert 6 effect evaporator to 5 effect

RB2 – RB optimizationAir/Liq distribution

CA2, 3 – Retrofit pressure filter, upgrade recaust

BSW2 – BSW retrofitRB8 – Soap separation

WRC 5,6,7–Improve chips screening, retrofit cooking

EC6 – Separate chloride from ash

Phase 1

Phase 3

Phase 4

Phase 2

✓

✓

RB3 – Recovery Boiler expansion

RB7– Lignin Extraction

RB4 – Install new RB

RB6 – Integrate BL Pyrolysis

WRC5 – Retrofit cooking

Alter.

Alter.

Alter.

Alter.

Alter.: Alternative (competing) projects

RB1- Revise the RB operating strategies

✓ : Implemented at the time of the project

Debottlenecking Opportunity Matrix


Priority projects to address the RB and evaporators bottlenecks → 2% Pulp production increase

Cost savings: 0.3 – 0.5M$/year in steam reduction/steam production increase

Implemented/Close to implementation Short Term Medium-Long Term (5-10 Years)

✓ : Implemented at the time of the project

Phase 1: Debottlenecking Opportunities Implemented/Close to Implementation

Status Project Description Project Type

Potential for Debottlenecking

Capital Cost

Adjust ejector set point, Reduce cooling water temperature Operation Low No

Ensure good causticizing control operation Operation Low No

Increase LP pressure (already implemented) Operation Low No

Improve wood chips screening/re-chipper to better control cooking

OperationRetrofit

LowLow

Medium

✓

✓




Capital Cost

Revise and monitor the RB operating strategies to reduce HBL variability Operation Low No

Integrate moisture measurement for efficient cooking Retrofit Low Low

Wood chips properties recording for efficient cooking Operation Low No

Reduce EA charge, increase T and residence time to reduce inorganics in the recovery loop

Operation Low No

Evaluation of BL composition /sesquisulphate to reduce fouling Operation Low No

Identify and fix the leaks to increase capacity of evaporators Retrofit Low Low

Add the ash to SBL instead of WBL to reduce fouling Operation Low No

Liquor circuit reconfiguration to improve washing Retrofit Low Low

Stabilize BSW dilution factor to reduce/stabilize evaporator load Operation Low No

Optimize split ratio of BL feeding different effects of evaporators Operation Low No

Priority projects to address the RB and evaporators bottlenecks → up to 6% Pulp production increase

Phase 2: Debottlenecking OpportunitiesMill Priority – Short-term





Capital Cost

Phase 1: Improve impregnation before the continuous digester Retrofit Medium High

New BL flash tank, - Capacity increase of cold blow coolers Retrofit Medium High

Capacity increase of digester line by increasing pump capacity Retrofit Low Low

BSW Improvements Retrofit Medium Medium

Soap separation from WBL/ Tall oil production Upgrade Medium High

Retrofit existing pressure filters for more filtration area Retrofit Medium Medium

Increase residence time in causticizers (size increase) Retrofit Medium High

Convert 6 effect evaporator to 5 effect Retrofit Medium Medium

Install external pre-heaters to increase capacity of evaporators Retrofit Medium Medium

Install a third heater to increase availability of concentrators Retrofit Medium High

Separate chloride from the ash, Purge chloride to reduce dead load Retrofit Medium High

RB optimisation (Air/Liquor distribution) Operation Low/Medium Medium

Priority projects to address the RB and evaporators bottlenecks → up to 8% Pulp production increase

Phase 3: Debottlenecking OpportunitiesRetrofit Medium Term Projects



Status Project Description Project Type Potential for Debottlenecking

Capital Cost

New RB Upgrade High Very High

Existing RB expansion Upgrade High Very High

BL PyrolysisProcess

ModificationHigh Very High

Lignin extractionProcess

ModificationHigh Very High

Phase 2 Increase continuous digester capacity Upgrade High Very High

Priority projects to address the RB and evaporators bottlenecks → >10% Pulp production increase

Alternative

Alternative

Alternative

Alternative

Phase 4: Debottlenecking OpportunitiesLong Term Strategic Projects



Status Project DescriptionProject

TypeType of Cost

ReductionPotential for

Cost ReductionCapital

Cost

Replace/retrofit coils and fans in machine RetrofitDryer steam consumption

Medium Medium

O2 delignification to reduce bleaching chemicals Retrofit BP Chemicals Medium High

Improve the feeding system to reduce dilution Retrofit BP Chemicals Medium High

Introduce Broke at final stage of bleaching OperationalBP Chemicals Low fiber loss

Low No

Recover the filtrate and use it in:digester and brown stock washing

RetrofitCooking

chemicalsET chemicals

Medium Low

Automate blow down and reduce it to 1-2% RetrofitIncrease steam

productionMedium Low

Further recovering deaerator vent heat RetrofitReduce steam consumption

Low Medium

- Sludge dewatering improvement- Hog moisture sensor

RetrofitIncrease steam

productionHigh High

Cost Reduction Projects



• A systematic diagnostic approach was used to identify, quantify, & classify process bottlenecks

• Operational projects & projects with low/medium CapEx would result up to 6% pulp production increase

– EBITDA potential ≥ 1M$/year

– The implementation of many of these projects can be supported by FPInnovations technical experts

• Process retrofit & upgrades are required to fully achieve the 10 % pulp production increase target

• A pathway for project implementation (mill ideas & new ideas proposed by the team) was proposed, whichpermits a gradual implementation for short-medium & long term opportunities while avoiding un-doing /reversing parts of the implementation

• Assessing the state of the existing mill assets is critical for improving mill competitiveness and for the selection of short to long term strategic decisions: start debottlnecking right at the root cause

Conclusions


Merci/Thank YouFor more Information, please contact:

Enrique Mateos Espejel Bahador [email protected] [email protected]: (438) 869-1531 Tel: (450) 652-4939

energy management and debottlenecking of pulp and paper

Documents