ABSTRACTS 2011

 

Technical Session 2A – PROCESS, CONROLS AND SUSTAINABILITY  

 

2A1          Pulp Machine Controls Optimization

Dan Laing, Canfor Pulp; Chris Roberts, Norpac Controls

 

While paper machines commonly have sophisticated control systems, pulp machines typically have only basic regulatory controls. This paper covers a scanner-based pulp machine MD controls project that included a thorough regulatory controls cleanup.

 

Long startups, frequent cutter plugs, high moisture and basis weight variability, and an underutilized million dollar dry end scanner drove a pulp machine instrumentation and controls upgrade at Canfor Pulp's Northwood Pulp mill. A thorough instrumentation and controls audit, from consistency meter calibrations to supervisory MD controls, was conducted over an eight month period. The audit led to instrumentation upgrades, valve replacements, control loop retuning, and control strategy modifications. A new supervisory MD controls package was installed that included coordinated production ramping, scanner-based per cent air dry and basis weight controls, and pulp wrap controls. 

 

Both sheet moisture and basis weight variability were reduced by 60%. Startups are much faster and smoother.

 

2A2          Gain Delay Retune in Multivariable Controls for the Paper Making Process

Stephen Chu, Joyce Chu, Honeywell, Vancouver

 

The paper making process, like many industrial processes, exhibits nonlinear behavior.  The nonlinearities can become more severe in situations where large operating condition changes take place.  Performing multivariable MD (machine direction) control based on linear process models formulated as first or higher order transfer functions in the Laplace domain becomes insufficient and inaccurate when these large operating condition changes are encountered.  The problem is that a multivariable MD control transfer function uses a static gain and time delay, which will vary with operating conditions in a nonlinear process.

 

This paper examines a solution that involves automatically retuning the gain and time delay based on nonlinear mass balance and process interactions.  The studied paper machine was in “slow-back” mode due to production limitations where the machine speed was almost half of its nominal speed.

 

2A3     Online Computation of Evaporator Balance via Least Squares at Intercon

Saul Mtakula,  Canfor Pulp Limited Partnership, Intercon Pulp

 

The online computation of Evaporator and Concentrator heat and material balances presents a wealth of diagnostic information for trouble-shooting  equipment operations. The conventional method for solving the balance is iterative in nature, proceeding in stages with solutions of a subset of parameters and substituting those parameters in subsequent sub-problems. The iterative method suffers from inaccuracies resulting from the fact that there are usually more balance equations than unknowns. The solution that one seeks is the optimal one and is in fact obtained by the method of least squares via linear algebra. We summarize the numerical solution for the balances of a six body Evaporator set at the Intecon mill. We show how balance equations were translated into matrix form, how the matrices undergo a bunch of transformations (transposition, multiplication, inversion) via some algorithms.  We discuss implementation issues speed of execution, numbers of variables etc) in both the Foxboro DCS and AspenCalc environment.

 

2A4          Process Analytical Technologies (PAT) implementation in the pulp and paper industry

Francesca Apruzzese, CPLP Intercon Pulp Mill and Paul Watson, Canfor R&D

 

Process Analytical Technologies are systems for analysis and control of manufacturing processes based on real time measurements of process and quality parameters for raw and in-process materials to assure acceptable final product quality.

 

In recent years, Process Analytical Technologies have been used by numerous manufacturing industries as powerful tools in order to reduce time for quality measurements, to improve process control without perturbing the system and to reduce waste as well as to increase product quality, while at the same time reducing production costs.

 

In this paper, after giving a brief introduction of the different PAT tools: multivariate data analysis, process analyzers and advanced process control modeling we will present some of the projects that are in progress at the 3 CPLP mills in Prince George for PAT implementation in NBSK pulp manufacturing.

 

2A5          Adding a Biomass-Fired Cogeneration Power Plant to a Natural Gas Processing Plant

Derek McCann, AMEC, Vancouver

 

Natural gas processing plants typically consume natural gas to generate steam for mechanical power and process heating use.  These plants remove hydrogen sulphide, carbon dioxide and extract hydrocarbon liquids from the incoming raw natural gas.  These plants are sometimes located remotely in forest management areas.  Such a location is the key to the concept of installing a biomass power plant at a natural gas processing plant.  Harvesting of local wood waste to supply this boiler could be economically viable.

 

A high pressure biomass-fired power boiler and a back-pressure steam turbine generator would replace the duty of the natural gas-fired power boilers in the gas processing plant.  The back-pressure steam turbine would exhaust into the existing steam system.  Internal natural gas consumption used for steam generation would be reduced or eliminated, imported electrical power would be reduced and there would be net reduction in greenhouse gas emissions.

         

2A6          Unbundled Engineering Services Deliver Substantial Insurance Cost Benefits

David C. Bennett, Corrosion Probe Inc. and Christopher E. Jackson, ARM, Global Risk Consultants Corp.

 

Large industrial companies, including pulp and paper manufacturers, require insurance companies with significant underwriting capacity to protect the companies’ business against large economic loss with property insurance coverage.  Most companies’ only option was to buy property insurance from a single provider large enough to underwrite the large loss potentials.  In a potential conflict of interest, the large insurance company would ‘bundle’ its own risk rating and loss-prevention engineering services into the policy, with fairly opaque, direct costs.  Meeting the insurer’s engineering ‘standards’ and requirements for reducing the risk or probability of a loss also can result in substantial secondary costs. 

 

In the ‘unbundled’ approach, a qualified independent organization approved by the underwriting community and extensively experienced with the risks associated with the plant’s equipment and production processes does the risk assessment and loss prevention engineering, making it possible for many insurance companies/underwriters to participate in the insurance coverage.  Replacing a single insurer’s bundled engineering with unbundled services from a dedicated, independent engineer alters the dynamics of how the services are provided.  It also widens the range of options the insured company can use to lower property risks and avoid losses.  Unbundled insurance adds complexity, but typically provides substantial direct and indirect insurance cost savings.  Our paper describes how to integrate unbundled engineering services into a full-service, property insurance program.  It also discusses benefits available with this modern approach to “Fire & Natural Disaster” and “Boiler & Machinery” insurance coverage.

 

Session 2B – DELIVERING ON INNOVATION

  

2B1          Benefits of FT-NIR Based Advanced Control of the Causticizing Process

Dharmesh Goradia,  Gavin Baxter,  Tembec Inc.,  Bruce Allison, Thanh Trung,  FPInnovations

 

The Tembec Skookumchuck pulp mill conducted a successful trial run of a system for automated lime addition to the slaker bowl based on advanced control and clarified green liquor composition analysis by an FT-NIR on-line analyzer. The FT-NIR demonstration unit and DCS programming were provided by FPInnovations. With the FT-NIR based advanced control strategy, the mill was able to raise the causticizing efficiency by up to 4%. Uptime for the analyzer was 85%, and it required minimal maintenance. The improved causticizing operation reduced consumption of purchased lime and decreased energy consumption in the evaporators. The cost reduction potential for this project was estimated to be $500,000/yr based on the 5 month trial. In addition to the above mentioned benefits, the mill also noticed other benefits with economic values that are more difficult to calculate, including; a decrease in the frequency of white liquor /weak wash filter sock acid washes, more consistent white liquor quality to the digester and better hot lime quality. After some initial nervousness, the operator acceptance of this technology was excellent during the trial period. Based on these results, the mill has decided to purchase a commercial FT-NIR analyzer.

 

2B2          Best Management Practices for Reducing Effluent Impact

Tobor Kovacs, P. Martel, B. O’Connor, FPInnovations; M. Hewitt, M. McMaster, J. Parrott, Environment Canada; D. MacLatchy, Wilfrid Laurier University;  M. van den Heuvel, University of PEI;  and G. Van Der Kraak, University of Guelph

 

Detailed studies at two kraft mills have demonstrated that both in-plant control measures and effluent biotreatment are important for minimizing organic losses and potential effects on fish reproduction. These studies have been carried out following the regulatory Environmental Effects Monitoring (EEM) program in Canada which found that pulp and paper mill effluents can alter the reproductive status of fish.  The studies were initiated to provide leads for alleviating such effects at kraft mills. For this purpose, the effluents from kraft mills were assayed in the laboratory for the potential to affect reproduction (egg production) in the fathead minnow. First, effluents from seven kraft mills were tested to assess current effluent quality. This was followed by more detailed studies at two kraft mills, including tests before and after effluent biotreatment. The effluent survey found a wide range of effluent quality, from effluent which caused complete inhibition of egg production to effluent which caused no effects whatsoever. The degree of effect was directly related to organic losses measured as biochemical oxygen demand (BOD).  Best management practices are important in reducing the impact.

 

2B3          Improving Pressroom Runnability through Strength Optimization with PapTuneTM

Nina Deng,  FPInnovations, Pointe Claire, Quebec

 

Pressroom runnability, more specifically web breaks, is an important performance issue for papermakers as it affects manufacturing cost and also the relationship with their customers. Many years of fundamental research done by FPInnovations has led to a web break model that quantitatively relates the number of web breaks to press variables and paper properties. The key paper properties that control web breaks are machine-direction (MD) tensile, stretch and strength uniformity. Our benchmarking analyses of many paper grades produced by various paper machines have shown that strength uniformity can vary significantly and has a significant impact on web break rates in the pressrooms. However, strength uniformity is a relatively new concept and cannot be easily obtained by mill people. To address this, FPInnovations developed a software program, called PapTuneTM, which allows mills to calculate the strength uniformity parameter, m-factor, using mill data obtained from pulp testing or automated paper testers. The strength uniformity can be linked to pulp quality variation and papermaking process changes, as well as pressroom web break statistics. In this presentation, we show how strength uniformity information can be combined with average tensile strength to better predict and optimize pressroom runnability performance. Case studies will be presented on how paper mills can use this tool to develop cost-effective strategies to improve their runnability performance and reduce manufacturing costs.

 

2B4          Troubleshooting and Optimizing Power Boiler Operation

Gavin Baxter, Tembec Pulp Group; Wenli Duo, FPInnovations, Vancouver

 

Energy cost is a critical factor affecting the competitiveness of a pulp and paper mill. Many mills now co-generate steam and electricity using wood waste or ‘hog fuel’ as the principal fuel in power boilers. Since hog fuel is considered to be a sustainable energy resource, greenhouse gas neutral, and cheaper than fossil fuels in many areas in Canada, mills are looking for opportunities and cost-effective technologies that can increase hog firing rate to produce more green power, improve energy efficiency to save fuel, and reduce emissions. FPInnovations has developed novel methods and equipment to sample, measure and analyze key operating parameters for optimization of fuel and air distribution to enhance combustion performance. The results enable us to quickly identify bottlenecking issues, leading to the best solutions for improvement.

 

This paper will present progress of a joint effort made for optimization of the power boiler at a BC kraft mill. Detailed evaluation of the performance of the boiler air system will be given, the results of optimization trials will be presented, and means to address the identified operating issues will be discussed, including equipment modifications and upgrades. Benefits generated from the current progress of this work are estimated to reach $1.5M/yr.

 

2B5          Near-Neutral Final Chlorine Dioxide Brightening: Theory and Practice

Zhi-Hua Jiang and Richard Berry, FPInnovations, Pointe Claire

 

It is well known that pH affects the effectiveness of chlorine dioxide treatment, but the standard recommendation has been to maintain a post-stage pH range for brightening with chlorine dioxide between 3.5 and 4.  In this paper, we will confirm that the optimum pH for final chlorine dioxide bleaching is dependent on chlorine dioxide charge but that this stage should be operated with a final pH close to neutral when a typical chlorine dioxide charge is applied. We will also show that maintaining a pH close to neutral throughout the bleaching stage is the ideal strategy. This result can be achieved under unbuffered conditions in some instances but is more consistently obtained by generating sodium bicarbonate in situ by adding carbon dioxide to alkaline pulp or sodium carbonate to acid pulp. In addition, we will also highlight the theory and practice of the near-neutral final chlorine dioxide brightening technology.

 

The near-neutral final chlorine dioxide brightening technology (NNB) has now been widely implemented in kraft mills across Canada.

 

Session 3A – CONTINUOUS IMPROVEMENT

 

3A1          On-line Dirt Count Analysis on Pulp Dryer Machine

Sami Riekkola, Metso

 

Dirt Count and brightness are most commonly utilized quality variables to classify market pulp quality.

Traditionally only brightness has been available through Quality Management Systems as on-line measurement where even bale-specific brightness is been made available for quality reporting solutions. Dirt Count Index has traditionally been analyzed with off-line analyzers using ccd-camera imaging to inspect a certain area of a pulp sheet.

 

Utilizing Web Inspection technologies it is possible to classify the on-line Dirt/Shive Counts of the pulp sheet, even covering the whole web width. This will require utilization of high-intensity LED-illumination to provide a transmission image of the +1000g/m2 pulp sheet. Also high-resolution imaging is required to provide analysis and classification of of shives and dirt spots from the range of 0,04mm2 to over 22mm2 sizes within the pulp web.

Classifying the dirt/shives  in the sheet according to TAPPI T:216 –standard with 17 dirt classes according to the defect sizes requires an on-line classification algorithm that analyses the transmission images in real-time during operation. Adaptation naturally needs to exist to any market standards in classification algorithm.

 

To enable reliable image analysis the illumination performance is the main challenge. Providing a good transmission image of a thick pulp sheet requires intensive illumination. The illumination requirement is equivalent up to 5000 W/m of metal halide light intensity.  Producing the illumination required on traditional light sources generates a significant amount of heat and introduces a maintenance challenge making the surfaces more sensitive for dirt build-up. The required illumination intensity can be achieved using strobing LED-technology. The benefit of the application is also low power consumption and thus low heat generation.

 

The measurement and analysis resolution according to T:216-Dirt Index standard is 0,2mm-0,2mm. Incorporating this in an on-line pulp dryer with a machine speed of over 200m/min requires also fast imaging technology. 100% sheet area coverage requires frame rates of over 100 fps with the required resolution.

 

Integrating the measured Dirt Count index with the quality variables measured in the on-line QMS system provides the total record of produced Pulp quality and solid quality record when applied together with reporting applications for bleached, semi-bleached and unbleached market pulp.

 

3A2          Development Tools for Market Pulp, Tissue and Towel Manufacturers:  Pilot Scale Tissue Manufacture and Laboratory Characterization.

Ho Fan Jang,  Dustin Olender, Val Lawrence,  FPInnovations, Vancouver; Stephan Lariviere, Jimmy Jong,  FPInnovations, Pointe Claire   

 

With global tissue markets growing steadily, while some other market segments such as printing and writing papers are in decline, Canadian pulp manufacturers are increasingly seeking market opportunities in this sector.  To support this growth, there is a need for research and development tools for both tissue manufacturers and pulp producers to develop new tissue grades and to demonstrate the performance of their pulps in tissue making.   To meet this need, FPInnovations pilot paper machine has been modified to manufacture tissue and towel grades, and numerous trials have produced tissue and towel samples that are comparable to high quality commercial products sold in the North American market.  Pulp preparation is separate from paper machine operation, allowing different refining strategies and blends for pulp furnishes.  In addition to the capability of producing pilot tissues and performing traditional tissue measurements, several novel measurement techniques have been developed to quantify tissue structure and related properties. Unique confocal and optical imaging tools combined with image analysis are used to analyze surface and bulk structures and microstructures, quantifying many important parameters such as surface roughness and creping properties that are related to tissue softness. As tissue properties depend not only on pulp furnish but also on sheet structure, these tools are important for determining the relationship between a tissue’s structure and its end-use attributes.  This paper describes the above tools for producing and characterizing tissue and towel sheets.

 

3A3          Capturing Value with Enhanced Fibre Analysis

Gail Sherson, FPInnovations and Andy Garner, Andrew Garner & Associates

 

Many mills in Western Canada process very high quality fibres which are the envy of competitors around the world.  These fibres bring performance advantages not only as reinforcement in printing papers, but for tissue products and many specialty applications. 

 

As pulp manufacturers seek new market opportunities, the need has never been greater than it is today, to fully exploit these fibre advantages for additional value. Fortunately, technological advances provide a new range of measurement tools for detailed fibre characterization from forest to product.  Some of these measurements are so precise that fibre properties can now be linked more directly with product performance and we no longer need to rely solely on the old-fashioned hand-sheet approach to measure physical properties such as tear, stretch and tensile.  For mill application, the latest development in on-line fibre analyzers is bringing real-time prediction of pulp performance much closer by adding measurement of fibre wall thickness and microfibril angle to the traditional measurements of fibre length and width.  This paper describes four new generation tools, spanning from forest to product, that are particularly suited for the high quality pulp production in the West.          

 

3A4          Pulp Dryer Automation Requirements When Converting to Value Added Pulp Grades

Dave Lang, Metso Automation

 

Many market pulp producers are considering, or are in the process of, converting to higher value grades such as dissolving or fluff pulp.  These new grades present new challenges compared to market pulp production.  Compared to market pulp, the customers of value added grades demand higher quality and that this quality be documented by the producer.

 

Traditionally, the pulp dryer in a market pulp mill has had a very low level of automation.  Many pulp dryers do not even have a scanner.  These would be standard in all other sectors of paper, tissue and board.  When the product is baled and shipped to the end user where it is re-pulped, a low automation level can be tolerated.  However, when the product is a chemical feedstock (dissolving pulp) or material designed for mechanical processing (fluff), this no longer the case.  For a successful mill conversion, it is important that these increased automation requirements be recognized and implemented.

 

This paper reviews the benefits of modern pulp dryer automation for market pulp and then explores the additional areas where customers of fluff and dissolving grades demand higher performance.  Mill results for pulp dryers are given for QCS automation systems and profilers.

   

3A5          Managing Mechanical Integrity of Fixed Equipment with Similar Disciplines to those Used to Manage Reliability of Rotating Equipment

David C. Bennett, Corrosion Probe, Inc., Centerbrook, CT

 

Maintenance of fixed equipment in pulp and paper mills typically consumes 15 – 20% of the annual maintenance budget: costs include inspections and related cleaning and scaffolding; repair of corrosion damage and, indirectly, lost production and cleanup costs from unplanned leaks and other incidents. These costs are substantially reduced by managing the mechanical integrity (MI) of fixed equipment in a pulp and paper mill with a disciplined approach similar to the core of reliability-centered programs for maintaining rotating equipment. The fundamental concepts involve creating a mill-managed program that uses the systematic inspection design (SID) process to combine knowledge of damage mechanisms, fitness-for-service methodology, risk-based prioritization and modern NDT technologies to transparently design a customized inspection plan for each major piece of fixed equipment, with

inspection intervals based on monitored damage rates.

 

Substantial savings come from eliminating illogical inspections, like thickness testing where ‘uniform corrosion’ is not possible, and from maximizing use of modern NDT technology to remotely or externally monitor known damage mechanisms wherever possible. The SID process reveals where it is smarter to mitigate damage mechanisms in order to eliminate inspections, cleaning, scaffolding, etc. The SID process is fully scalable - providing similar engineering and economic benefits for just a few tanks, a recovery boiler and a pulp mill. A feedback review cycle makes sure each SID derived inspection plan is continuously improved, steadily reducing maintenance costs and improving equipment reliability.

 

Another economic benefit of the SID process is improved reliability of fixed equipment: fewer leaks, failure, and other surprises increase plant safety and minimize lost production. The objective and transparent SID process readily adapts to mill process improvements and, by consistently generating the same inspection plans regardless of who does the planning, is not affected when the program coordinator and other key area practitioners change.

 

3A6          Managing Metals Leads to Improvements in Bleaching of Kraft Pulp and Mechanical Pulp.

Michael R. Elsey,  David R Jones, Buckman

 

The use of commodity type chelants to control metals in bleaching is not a new development.  In oxidative and reductive bleaching, metals are a negative factor.  The metals can breakdown the bleaching chemistry and also are a major factor in brightness reversion.  While the use of commodity chelants such as EDTA and DPTA is common they are usually part of the bleaching liquor and are applied mainly in the pulp mill.

 

Buckman has developed a new family of metals management products that have proven effective in improving bleaching in kraft and mechanical pulp.  These products are part of a new strategy in metals management that expands the focus of reducing brightness reversion and protecting the bleaching chemicals for optimum performance and cost savings.   Application may now be in the pulp or paper mill depending on the goal of the program.

 

As with all chemical programs application is important.  A thorough knowledge of the system is essential.  One important parameter is pH as this has an effect on the metals management product as well as on the metals themselves.  An understanding of the system and the products results in the optimum program to manage the metals and provide the greatest benefit.

 

This paper will present the new family of metals management products with case studies that show the application and benefits of effective metals management, including brightness gains and bleach cost savings.

 

  

Session 3B – PROJECTS, PRODUCTION AND PROFITS

  

3B1          Results of Inferential Control of the Intercon Causticizing Process

Saul Mtakula,  Canfor Pulp Limited Partnership, Intercon Pulp, Bruce Allison, FPInnovations

 

The goal of this project was to demonstrate improved control of the white liquor causticizing efficiency (CE). Lime addition to the slaker was determined by a stoichiometric calculation from the clarified green liquor composition and an inferred lime availability. The lime availability estimate was determined by an estimator driven by the error between model-based predictions of the slaker temperature and 1st and 4th causticizer CE values versus the actual measurements. Pseudo-continuous CE measurements were determined by 1st and 4th causticizer CE soft sensors where conductivity was used to predict the CE values between tests. Both the stoichiometric feedforward calculation and the CE soft sensors used for feedback were driven by operator tests entered every two hours. All of the control functionality was implemented directly in the DCS. Implementation of the controls has resulted in a 30% reduction in white liquor CE variability and an increase of the average CE from 79% to 80%.  Since the mill is recovery limited, the decrease in deadload associated with an increase in CE translates into a potential incremental pulp production of 1000t/y per each 1% increase in CE.  Based on these results, we estimate that an on-line analyzer would enable a further 2% increase in CE to 82% and an incremental 3000t/y in production.

 

3B2           First Shoe Press Upgrade to North American Pulp Machine

Paulo Kapronczai, Hinton Pulp

 

In 2007 Hinton Pulp Mill went through a major restructure in order to stay competitive in a tough market. The restructure included shutting down the mill’s original vintage 1950’s Minton Dryer. The issues with that machine were primarily maintenance costs and quality constraints. The biggest challenge was how to increase production on the existing 5 bale, 4 meter Black Clawson wet end and Flakt dryer. The #2 pulp machine production was 850 ADMT/day machine but with the addition of a shoe press, head box upgrade, dryer fan rotor upgrade, increased steam pressure, and table extension the new rate was expected to be 1050 ADMT/day. In 2010 the MSR for the #2 pulp machine was 1192 ADMT/day with a daily record production of 1252 ADMT. This was the first rebuild of its kind in North America.

 

3B3          Methanol Purification at Alberta Pacific Forest Industries

Jamie Percy, Alberta Pacific Forest Industries

 

Alberta Pacific Forest Industries (Alpac) is the largest single-line bleached kraft pulp mill in North America, running campaigns of both hardwood and softwood pulp. The conventional kraft pulp mill process used at Alpac generates a waste gas stream called stripper off gas (SOG), which consists of 50% methanol, with the balance being mostly water. In the past the SOG stream could only be incinerated to recover the energy in methanol because SOG also contains other impurities (sulphur compounds, ammonia, terpenes and terpene alcohols, etc.). With the implementation of this project, the methanol will be separated from the other components in the SOG stream and purified to 99.85wt%. Alpac will be the first mill in the world to separate and purify methanol from the SOG using a novel distillation technology.

 

Presently, methanol is purchased for use on-site in the production of chlorine dioxide, which is used in the pulp bleaching process.  About 30% of the methanol produced from this project will completely replace the purchased methanol.  The remaining methanol will be sold to external industries that use methanol. The expected project cost is $9.0M.

 

In addition to the expected economic benefits, there are process and environmental benefits.  Purchased methanol is generally produced from natural gas in facilities that are often at a significant distance from Canadian users. ‘Biomethanol’ produced at Alpac will replace the purchase of fossil fuel-based methanol and will conserve the energy associated with the transport .  As a process benefit, the SOG will no longer be burned in the kiln, which can cause  kiln ringing, resulting in production losses.   

   

3B4          Bleaching Committee Surveys:  Bottlenecks & Final P Stages

Dan Davies, Evonik Degussa Canada Inc., Surrey, BC

 

The Pulp and Paper Technical Association of Canada Bleaching Committee is a group of Pulp & Paper industry representatives comprised of mill personnel, research personnel, suppliers, consultants and academics. All of the representatives are members of PAPTAC, the Pulp and Paper Technical Association of Canada.

 

The group meets twice a year to discuss the latest developments and technologies in the field of chemical pulp bleaching. These meetings are also a forum to discuss and solve the latest technical challenges or problems which face individual mills. During the year, subcommittees work on projects which are of interest to the committee and to the Pulp & Paper industry as a whole.

 

As part of the ongoing work by the Committee, surveys are performed on various aspects of the industry.  Previous surveys included Bleaching Best Practices, Bleach Plant Washers and Cost Savings Ideas.  These surveys are chosen during meetings as topics of common interest to the members.  The surveys are conducted by an email-out via the committee’s listserv (a service that allows members to send an email to a single address and have it distributed to all current members) and as a posting to the committee’s web forum.  Members can respond by email directly to the person originating the survey or by posting to the web forum.

 

Once the data has been gathered, it is assembled, analysed (if needed) and distributed to the members by email (via the listserv), posting on the forum and by presentation at the next committee meeting.  As two surveys were performed recently, it was decided to present the results together at the PacWest conference.  These surveys are on Bottlenecks in the mill’s processes, and on the use of Final P Stages.

 

3B5          Causticizing and Lime Kiln Process Optimization

Mike Wolfensperger,  Metso

 The recovery area processes (evaporation, recovery boiler, and causticizing / lime kiln) have great opportunity for energy savings.  This paper will focus on the causticizing and lime kiln area.  Increases in green liquor total titratable alkali and  causticizing efficiency reduce deadload and improve the efficiency of the entire liquor cycle.  Finally, better management of the lime kiln reduces specific energy consumption and improves lime quality.  This paper will discuss the potential to improve energy efficiency through the implementation of Advanced Process Controls.

 

3B6          Recovery Process Optimization

Jukka Puhakka,  Metso

 

The recovery area processes (evaporation, recovery boiler, and causticizing / lime kiln) have great opportunity for energy savings.  Higher dry solids and improved steam consumption can be achieved in the evaporators.  Optimization of the burning process results in a stable steaming rate from the recovery boiler.  Adaptive sootblowing control enhances the boiler availability.  Increases in green liquor total titratable alkali and  causticizing efficiency reduce deadload and improve the efficiency of the entire liquor cycle.  Finally, better management of the lime kiln reduces specific energy consumption and improves lime quality.  This paper will discuss the potential to improve energy efficiency through the implementation of Advanced Process Controls.