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Weyerhaeuser installed a new high-solids crystallizing concentrator in 1995 in its Longview mill. The enhanced design combined the easy operation and fouling resistance of original models with a power consumption rate that is 40% lower than the original design. Operators do not need to pay much attention to the system because of its stability and high degree of automated control. Future designs are expected to use even less power., In 1993, Weyerhaeuser retained HPD (now a division of U.S. Filter) to provide a black liquor concentration/pre-evaporation system. The system consists of two enhanced high-solids crystallizers, a conventional (un-enhanced) intermediate [...]

Woodships, bark, and other wood materials are transported through the use of screw conveyors which rotate and move along the bottom of the pile. Screw breaks have the potential for shutting operations of a paper mill. However, maintenance and load analysis can prevent downtime. Load applications and improved loads, along with pile height and shape, and material density must be considered, as well as welding anomalies and load stress., By rotating and moving along the bottom of a pile of wood material that is often more than 80 ft high, screw conveyors transport such products as woodchips, bark, and [...]

The implementation of advanced process control technology helps paper mills boost their profitability and quality of their products. Mills need to get familiar with the specifications of control systems prior their installation. Mills can keep their process control systems functional by properly training support personnel and creating process control teams to maintain the systems. Some mills are using the services of control system suppliers' onsite support specialists or third parties to manage their control systems., Control Technology is changing at an extremely rapid pace. In the past 20 years, paper mills have gone from pneumatic control systems using basic control strategies to CRT-based distributed control [...]

Pulp producers have been striving to drastically minimize, or in some cases replace, the use of chemicals containing chlorine in bleaching kraft pulps. This action by pulp producers is in response to market pressures and calls by environmental organization that have expressed their concern regarding the use of chlorine-containing chemicals in pulp bleaching. The development of extended delignification technology since 1984 has helped pulp producers to minimize their use of contaminants in bleaching., IN THE PAST FEW YEARS, BOTH ENVIRONMENTAL and market pressures have intensified the pulp industry's efforts to replace or significantly reduce the use of chlorine-containing chemicals in the bleaching of [...]

Mechanical design of blowtanks and high-density tower agitators for pulp and paper mills must accommodate constant high-amplitude variations in impeller blade forces due to changes in consistency and intermittent shock loads. Mechanical design considerations include sizing parameters, location of dilution and recirculation lines, zone sizing, use of a horseshoe fillet, requirements for startup and operation, and mechanical reliability. Common problems include poor consistency control, upsets and mechanical failure., ALTHOUGH ALL PULP STOCK CHEST AGITATORS must perform to expectations, most of the performance problems--either process or mechanical--can be found in such severeduty applications as blowtanks and high-density towers. From [...]

Premium-efficiency motors offer paper and pulp mills the potential for reduced electricity bills, but that energy savings must be weighed against the higher initial price, usually about 25% more than a comparable standard motor. Cost of electricity and operating hours are the two main factors that determine the cost effectiveness of high-efficiency motors. Size and type of motor should also be considered, with greatest potential cost reduction for 1-125 hp motors. Savings up to 50% can be obtained with centrifugal pumps used in closed-loop throttling systems., ALERTED BY THE ENERGY ACT OF 1992, MANY users of AC induction motors seem to be eyeing premium-efficiency motors with mixed feelings, perhaps some confusion. When the October 1997 deadline [...]

Factors to be considered when selecting a gear drive for pulp and paper mills include the service factor, gear drive rating, thermal capacity, speed variations, equivalent horsepower, gear ratio and size. The service factor, which is used to figure equivalent horsepower, is based on external load dynamics, reliability and longevity. Shaft-driven fans and commercial air-to-oil radiators are recommended to improve the thermal capacity of the gear drive., GEAR DRIVES CAN BE A 'LIFELINE' IN MANY operations within a pulp and paper mill. And, with an increasing emphasis on operating efficiency, selection of the proper drive has become [...]

Oxygen delignification systems are helping the paper industry in North America reduce chemical discharges associated with chemical pulp bleaching. Since 1990 about 40 oxygen delignification systems have been installed at paper mills in the US and Canada. Alabama Pine Pulp Co. uses a Kamyr two-stage oxygen delignification system at its Perdue Hill, AL, mill. Pope & Talbot Inc. uses an Impco oxygen delignification system at its Halsey, OR, mill. A Sunds Defibrator oxygen delignification system is used by Canadian Forest Products Ltd's Prince George, British Columbia, mill., OXYGEN DELIGNIFICATION HAS BECOME THE MOST cost-effective technology in reducing environmental discharge associated with chemical pulp bleaching. Driven by legislative and market forces, U.S. and Canadian mills have installed nearly [...]

Westvaco Corp.'s installation of a bleached paperboard machine at its Covington, VA, paperboard mill ends a three-phase, $750 million, 10-year expansion project. The latest bleached paperboard machine is the second such machine in the facility and began operating on Sep 30, 1993. The expansion project included the addition of two paper machines, a new recovery boiler, coating formulation area, pulp mill upgrades, woodyard and waste treatment modernizations and a converting facility. The company is predicting it will produce 750,000 tons of bleached paperboard in 1994, a 22% increase over 1993 production., WESTVACO CORP.'S LATEST pulp mill expansion and new paper machine at its Covington, Va., mill is a $400-million culmination of an almost 10-year project. The three-step expansion--which totaled $750 million--included [...]

Selecting couplings used on papermaking machinery in paper mills requires engineers to conduct a thorough evaluation of their design and how they will be used. There are four types of gear coupling engineers have to choose from: gear, disc, grid and elastomer. Gear couplings have the highest resulting service factor, but are limited by bore capacity. Areas such as stiffness, torsional deflection, backlash, misalignment capacity, axial float capacity, shaft gaps and prices need to be evaluated before a coupling selection is made., PULP AND PAPER MILLS, ALONG WITH LUMBER-yards, provide a myriad of applications for shaft couplings, including chippers, conveyors, agitators, pumps, mixers, pulpers, winders, calenders, dryers, and paper rolls. No one [...]

Paper mills have a choice between a mechanical rebuild of equipment or one that uses papermaking chemistry to decrease expenses, increase production or come up with new paper grades. The interactive chemical rebuilding process is to the paper mill machinery as software is to computers. The process is inherently more flexible and efficient and is based on microparticle technology., Papermaking chemistry can have the same effect that software does on computers, making paper mill machinery more flexible and efficient TO LOWER COSTS, EXPAND PRODUCTION, OR make entirely new paper [...]

Pulp and paper mills are constantly faced with varied maintenance problems on their respective applications and lubrication programs. As a response to such problems, paper mills are considering lubrication suppliers as an integral part of their maintenance operations. To meet the growing needs of pulping and papermaking equipment, many new additives have been developed by lubrication suppliers. In addition, these suppliers have also offerd ongoing data collection and analyses programs that allows effective monitoring of lubricants throughout the process., New additives, better lubricant monitoring help pulp and paper mills manage faster operating speeds and higher temperatures Selecting a correct lubricant for machinery in the woodyard, pulp mill, and paper [...]

Manual adjustment screws used to be added to blade coaters to promote better coat-weight uniformity and prolong blade and backing roll life. However, manual adjustment cannot react fast enough to short-term process and product changes. Automatic actuators are available for the replacement of manual adjusters, allowing immediate response to these changes. ABB Process Automation has provided five blade coater profiling systems as of May 1993, helping several mills in reducing long-term cross-direction variability by 35%., Automated system installed at several mills can significantly reduce CD variation, as well as time needed to get on grade after blade change For many years, blade coaters have incorpor [...]

The use of mechanical seals on rotating equipment used in the pulp and paper industry is gaining importance due to rising water, energy and effluent treatment costs and the enactment of tough environmental regulations. Cost-reduction programs can benefit greatly from advances made in mechanical sealing technology, which can contribute to the enhancement of emission and effluent control and the creation of effective cost-reduction programs. Provided they are implemented properly, seal conversion and cost-reduction programs will can both protect the environment and increase profit margins., High initial cost of rotating equipment components claimed offset by economic and environment operating advantages The rationale for using mechanical seals on rotating equipment in the pulp and paper industry [...]

Union Camp Corp. has started using what is known as the OZEoD sequence in bleaching pine. The company invested 15 years and $113 million to create the OZEoD sequence, which is the first ozone-based system of its kind to be manufactured and used in North America. The primary function of the system, which is being used at the company's Franklin, VA, paper and paperboard mill, is to reduce effluent color and volume that is released into a river. Union Camp is offering the process technology to other mills wishing to produce pulps that are totally chlorine-free and to close up their effluent systems., Integrated free paper and paperboard mill approaches total effluent closure with 1,000-tpd OZEoD 'C-Free' softwood bleach plant Six weeks ago, Union Camp Corp. started up one of the most environmentally [...]

Fiber Charge Analyzers Monitor Furnish to Optimize Production Used for a variety of paper and board furnishes, analyzers recommend adjustments in application of wet end additives Since furnish charge affects [...]

This article examines the relative merits of three currently available brownstock washing BSW systems. A case study example compares each system in terms of process and operating considerations, site requirements, [...]

Enclosed PM Hoods Operating at High Humidity Conserve Energy Energy consumption optimized by controlling dryer environment, minimizing airflow, recovering most heat from hood exhaust Water removal by drying paper and [...]

Capital Spending Plans: 1990-92 Paper industry capital spending has boomed for the past two years, but the slowdown in business that began last year will lead to a slowdown in [...]

High-Purity Boiler Condensate Can Save Energy, Reduce Costs Maximizing the return of pure, heat-laden condensate to the boiler system is an important goal in pulp and paper mills. Condensate returned [...]

New Recovery Boiler Joins Second Paper Machine in Miramichi Expansion Added steam output, reduced emissions are achieved in supporting new groundwood and free-sheet paper line Miramichi Pulp & Paper Inc. [...]

Packaging-Grade Mills Boost Quality and Output with Multilayer Fabrics As conversion to multilayer forming fabrics continues, more mills report new production and wire life records as well as enhanced sheet [...]

Continuous, Stable Kiln Operation Is Key to Extended Refractory Life In today's pulp and paper industry, refractories for the lime recovery or lime sludge kiln have become extremely important to [...]

Bladin Paper Completes $350-Million Lightweight Coated Expansion Project Bladin Paper Co., a wholly owned subsidiary of Fletcher Challenge Canada Ltd., has been making paper in the northern Minnesota town of [...]

Today's Shoe Presses Designed For Optimum Sheet Quality, Runability Modern units such as that installed at La Cellulose du Pin's Facture mill in France provide maximum dryness and optimum sheet [...]

Chemical Felt Conditioning Programs Can Boost Press-Section Efficiency Modern press section designs require a thorough economic evaluation to determine the most effective felt conditioning system A great deal of attention [...]

Proper Recovery Boiler Care is Key to Reliable, Productive Operation Damage to a mill's black liquor recovery boiler (BLRB), when no alternate means for chemical recovery exists, can halt or [...]

Used Lift Trucks Can Be Wise Choice for Mills that Evaluate Thoroughly Paper mills considering the acquisition of a lift truck can save up to 35% by purchasing a used [...]

COMBINATION CORROSION COUPON TESTING NEEDED FOR TODAY'S CONTROL EQUIPMENT Copper, silver, and gold are important functional materials found in many of the electrical/electronic devices in today's pulp and paper mill [...]

NEUTRAL SIZING SYSTEM ALLOWS FAST, EASY CONVERSION FOR ACID MACHINES Recent pilot machine and mill trials have shown that rosin sizing at neutral pH works well under operating conditions commonly [...]

Potlatch Corp plans to upgrade the control of the multi-fueled boiler at its paper mill located in Lewiston, ID. The mill has developed a new system to monitor the boiler water which consists of a trend graph for each analyzer which stores continuous values for the last 30 days. A Microsoft Excel spreadsheet package accesses real-time data of the new process control system. The mill plans to convert the boiler to DeltaV control., How does an integrated pulp, paper, and saw mill modernize 25-year-old controls running a 600,000 lb/hour, 950 [degrees] F multi-fueled boiler? This was the question faced last year by Roy [...]

Pulp and paper mills which plan to maintain their equipment need to carefully evaluate repair firms before contracting their services. Mill maintenance departments consider independent repair firms' services more economical and advantageous than those offered by original equipment manufacturers. Mills need to take into account the expertise of independent repair firms in restoring badly damaged equipment parts and in-service warranty. Mills also need to implement cost-avoidance programs to eliminate unnecessary expenses related to equipment maintenance., TODAY, AN EFFICIENT REPAIR system for pulp and paper facilities is more important than ever, and cost is the driving force. Spares have gone up in value during the past [...]

The Champion International Corp mill at Roanoke Rapids, NC, experienced operational problems in the precipitator in the early 1990s due to corrosion, and equipment replacement was considered the best solution. A 'turnkey' solution was adopted with new a new precipitator supplied by Environmental Elements Corp of Baltimore, MD. The project was a success with the use of tie-ins and working during regular maintenance outages., Operation at champion international's mill in Roanoke Rapids, N.C., began in 1906. Today, the mill produces about 1,400 tpd of unbleached kraft paper and paperboard, including linerboard, grocery bag, and [...]

New, more responsive computer-controlled basis weight control valves are leading to less stock loss and more uniformity as the stock flows into the wire. The valves allow better stiffness, smoothness, printability and other features. The overall price of a new valve package is between $11,000-$30,000; mill managers who are considering the purchase of a particular valve should talk to a mill that is using the equipment successfully., BASIS WEIGHT IS ONE OF THE FEW PAPERmaking variables that can be changed while the paper machine is running and is, therefore, a key to optimizing paper quality and mill [...]

The U.S. Paper Industry's 1995 New Technology Show Tour visited about 25 pulp and paper mills in the Southern states. Record attendance included higher numbers of management personnel plus maintenance workers and administrative employees. Included is a list of the 31 companies that exhibited and the types of equipment and services displayed., The spring 1995 version of the U.S. Paper Industry New Technology Show Tour attracted personnel from more than 25 pulp and paper mills in the southern part of the country. [...]

Blandin Paper Co eliminated chlorine from its water treatment process at its Grand Rapids, MN paper mill by using other chemicals stored in rotationally-molded plastic tanks. The bleach, bromide and coagulant that replaced chlorine at the plant are stored in four 2,000-gallon and three 3,000-gallon polyethylene tanks. The tanks are cheaper than stainless steel and are not affected by the chemicals. Installation and plumbing were simple and the tanks can be almost completely drained., Last summer Blandin Paper Co. converted its raw water treatment process away from chlorine to a special three-chemical (bleach, bromide, coagulant) system. Stored in seven plastic tanks at the mill [...]

Niagara of Wisconsin Paper Corp. has completed an upgrade to its paper mill that included the addition of a totally chlorine-free kraft pulp to its groundwood furnish, conversion to alkaline paper production and a new coating plant. Niagara, a producer of virgin and recycled coated groundwood publication papers, is the first groundwood mill in North America to offer postconsumer recycled content. Niagara incorporates 30% recycled fiber in its stock, and was the first North American groundwood mill to do so., NIAGARA OF WISCONSIN PAPER CORP. IS COM-pleting a major three-phase upgrade that features the addition of totally chlorinefree (TCF) kraft pulp to its groundwood furnish, a new coating plant, and [...]

Fine paper mills can increase production speeds, improve quality and reduce energy costs, by using film-type size presses. Puddle-type size presses are limited to about 3,000 fpm with large-diameter press rolls and about 2,600 fpm with smaller rolls. Film-type size presses increase production efficiency, and break reduction rates of between 70% to 90% are common. Additional benefits of film-type size presses are discussed., FOR DECADES, MANUFACTURERS OF fine paper have relied on the conventional puddle-type size press for applying surface size to a broad range of paper grades (Figure 1). Through refinements in [...]

Alberta-Pacific Forest Industries Inc's bleached kraft paper mill near Athabasca, Alberta, uses custom alternating current (ac) motors and adjustable-speed drives. Engineering services for the 1,500-metric tpd mill, which started operating in Aug 1993, was provided by H.A. Simons and the Stanley Group. The combination of ac motors with adjustable-speed drives allows reliability and precision speed control in continuous mill operations., * Boyle, Alta.'s 1,500-metric-tpd mill installs a.c. motors and adjustable-speed drives for operating reliability and maintenance ease THE ALBERTA-PACIFIC FOREST INdustries Inc. bleached kraft market pulp mill located near Athabasca, [...]

The careful selection of individual control valves for pulp and paper mills can substantially improve productivity, reduce maintenance downtime and prevent corrosive processes. The different valve types, such as the V-notch ball valve, the high-performance butterfly valves, and the post-guided globe valves, can be chosen with fundamental guidelines based on cost, performance and service life., Individual control valve designs can withstand corrosive processes, improving productivity and reducing maintenance downtime CHOOSING CONTROL VALVES FOR PULP AND paper mill applications can be made painless by following fundamental [...]

Companies often spend huge sums on distribution control systems, computer systems and optimization programs but do not ensure optimum control valve performance levels. They fail to realize that poor control valve, transducer, transmitter and analyzer performance can greatly affect quality and production. Modern mills require valves which can handle highly corrosive and erosive fluids and can adjust to small and rapid demand changes. Mills should therefore observe strict control-valve performance specifications and ensure proper valve maintenance. Valve suppliers should also be selected carefully., Control valves must have the ability to perform to the same advanced levels as contemporary control systems The 1980s could be titled the Decade of the Distributed Control System (DCS). [...]

Installations of a newly designed steam injection have significantly improved steam heating applications at many pulp and paper mills. The new design features a side port entry of steam, which then spreads inside, coaxially flowing with the product being processed. The steam and the liquid-phase product are then divided into six streams and are made to spin. The structure of the device allows noise reduction and absolute removal of vibration. The device is effective in several pulp mill applications, including pulp stock, green liquor and makeup water., Installations prove successful in various pulp and paper mill steam heating applications, including pulp stock, green liquor, and makeup water For more than 100 years, it has been common industry [...]

325,000-tpy uncoated free-sheet machine comes online as part of $500-million mill expansion project, bringing total capacity to more than 800,000 tpy Georgia-Pacific Corp.'s mill at Ashdown, Ark., is now the [...]

Although they may be losing favor to the more effective flooded-nip and wash-roll-doctor knockoff (KO) techniques, conventional knockoff showers vary widely in performances. For those machines continuing to use knockoff [...]

Port Townsend Improves Pulp Quality with Chip Thickness Screening System Port Townsend Paper Corp., located in Port Townsend, Wash., is a batch process kraft mill that produces unbleached pulp and [...]

E.B. Eddy Brings Computerized Starch Makedown System Online Operator involvement in the design is cited as the key to the successful operation in Espanola, Ont., mill Operator involvement in all [...]

Increased Use of Wastepaper Spurs Improvements in Pulper Efficiency Repulping of wastepaper has traditionally been performed either in continuous or in batch pulpers, with consistencies that normally range from 2.5% [...]

Today's Wide, Fast Paper Machines Require No-Problem Fabric Guiding Economics of modern fourdrinier operation mandate minimum downtime and few operating problems related to the guiding of forming fabrics The history [...]

Machine-Specific Clothing Designs Can Boost Mill Profits, Operation Numerous variables must be considered for forming, pressing, and drying fabrics; tailored clothing wins over 'bargains' As every papermaker knows, each paper [...]

Blandin Paper's New Coater Features Latest Technology, Control Strategy Off-machine coater at Grand Rapids, Minn., paper mill provides consistent coating weights and superior runability at up to 5,000 fpm In [...]