Brazil's No. 3 Eucalyptus Producer Employs Newest Pulping/BleachingTechnology

By Harold M. Cody,Editorial Director

Votorantim Celulose e Papel SA (VCP) is one of Brazil's fastest growing pulp and paper companies. This aggressive growth, which has involved a large capital investment program in the last fiive years, has propelled the company into Brazil's number three spot in eucalyptus pulp production. The company is a leader in specialty papers (thermal, carbonless, and security grades) and printing and writing papers, and its recent expansion has increased pulp capacity to over 2000 mtpd, including 1000 mtpd at the Luiz Antonio mill.

In addition to being fast-growing, the company's philosophy about employing new technology is also on the cutting edge. The recent expansion at the Jacarei mill, about one hour by road from Sao Paulo, incorporates the newest technology available in the fiberline area, including several firsts for the Brazilian industry. If its long-term plans for further expansion go forward, the mill site will become one of the largest single line pulp mills around.

VCP acquired the Jacarei mill from Simao in 1992. The original mill was built on the site many years ago. However, owing to the fact that this mill was operated using batch digesters and an ancient recovery boiler, the company quickly began to transform the facility into a world class operation.

The recently completed $220 million project follows a substantial $130 million upgrade to the mill that took place in 1994, setting the groundwork for more expansion. The two phases of the project have been combined to build a new pulp mill in place of the old original line, which was installed in 1958 and used batch digesters. Once the current expansion was completed, most of the old pulp mill was closed.

New bleach plant towers with recovery boiler in background.

Key elements of the 1994 project included raising bleach plant capacity on the existing line to 600 mtpd, and adding a new recovery boiler, evaporator plant, turbo-generator and boiler water treatment system. Basic engineering for these projects was completed internally via the corporate engineering staff, according to Carlos Monteiro, General Manager of Corporate Engineering and head of all expansion projects at VCP.

PULP MILL HAS POTENTIAL TO REACH 2000 MTPD. The recent project, begun in 1996 and completed in the fall of 1997, essentially added a new pulp mill. Major components of the project included an Ahlstrom Lo-Solids hydraulic continuous digester, Kvaerner bleach plant, FL Smith limekiln, upgrades to the recausticizing area, and a Sunds wet lap pulp machine with an ABB dryer. An existing limekiln was shut down following the startup of the new unit. A new ABB control system controls the entire pulp mill.

Ahlstrom's scope of supply included a DiamondBack chip bin, the first in Brazil, as well as providing erection supervision. This is the first Lo-solids Ahlstrom unit in Brazil; it came online in May 1997. The digester is currently operating at about 1150 mtpd. However, according to the mill, the digester vessel is rated at 1500 mtpd, and with some modifications could process over 2000 mtpd. The mill is currently studying such an expansion as part of the company's aggressive push into the paper industry.

New bleach plant towers with recovery boiler in background. The pulp mill following the digester is now a two-line configuration with the old bleach plant running at 350 mtpd on standard pulp with a 600 mtpd capacity. The new bleaching line is running at 800 mtpd mainly ECF grades but has the capability to make TCF grades as well.

1500 mtpd digester can be expanded to 2000 mtpd in future.

Also currently under construction is a new 38 MW Siemens turbo-generator plant scheduled for startup in November 1998. This will cut purchased power use from the current level of 50% of electrical power needs down to 10-15%. An oil-fired power boiler and one biomass boiler are used for steam generation. Upon startup of the new limekiln the old unit was shut down. The original pulp mill comprised of batch digesters still exists, but is not used.

The mill's upgraded recausticizing plant is state-of-the-art, having installed both green and white liquor filters. These are X filters for green liquor filtration and a CD filter for white liquor production, both from Ahlstrom. The use of filters provides very high quality liquor and contributes to good digester operations while being environmentally friendly, according to Marcelo Castelli, recovery and utilities manager at the mill. The new FL Smith limekiln has flash drying and a precipitator. The low-odor recovery boiler is used to burn NCG gases, a practice at both VCP mills.

As part of the pulp mill expansion, added market pulp drying capacity was required as the existing pulp machine couldn't handle the extra load. A new Sunds pulp dryer, with an ABB Flakt dryer and a Valmet cutter/layboy was installed.

Following the expansion, the mill has become very competitive with other major producers, reports mill manager Jose Schappo. Mr. Schappo believes the recent economic growth in Brazil bodes well for the future, and thinks Brazil will continue to expand its pulp and paper industry, due to the rapidly growing forest and the quality of eucalyptus pulp.

The mill is now positioned to serve a growing offshore base for pulp buyers. With the added pulp capacity, the mill can now export some 800 mtpd in addition to providing pulp to other VCP mills. The mill is selling market pulp into Europe, Brazil, and the U.S. and reports that quality is very good.

According to Jose Patelli, pulp manager, VCP's strategy is to have intensive client assistance for its customers. The mill sees TCF pulps as an important market, but it mainly sells ECF, which has a very low AOX, due to its unique bleaching sequence. Target markets include expanding pulp use in tissue products, where it has extensive contacts in Brazil, as well as use for printing and writing papers.

Ozone Bleaching Stage. An interesting aspect of the new bleach plant line B, supplied by Kvaerner, is ozone-bleaching capability. Two large units operated by OZONA (Air Products produces oxygen and Air Liquide ozone) provide ozone "over the fence". These generators are the largest in the world, according to Marco Antonio L. Peixoto, a sr. process engineer at the mill. Each unit produces 90 kg/hr.

Figure 1: Line B Bleach Plant Flowchart

VCP is the only mill using ozone to produce substantial amounts of eucalyptus hardwood market pulp. The mill is working to improve reliability of the fiber line, as one limiting factor is having only two large ozone generators. If one goes down they can add more ClO2 and peroxide.

Kappa number out of the digester going to the pre-bleach plant is currently 14, but after some modifications are completed this will move to about a kappa number of 16. Current use of ozone is about 5 kg/ton in both ECF and TCF pulps.

The market pulp made by the mill has a target brightness of 90 ISO, a dirt count of less than 2 mm2/m2 and viscosity greater than 700. Target markets for their pulp, in addition to printing and writing mills, are tissue mills.

One of the features of the new bleach plant is a low level of effluent. Currently only 5m3/ton of pulp go to effluent treatment from line B. The current treatment plant was not modified as part of the recent expansion. It uses primary sedimentation followed by stabilization lagoons. In order to expand pulp capacity up to the level under study, the mill will need to add an activated sludge operation. Currently, the mill is not required to meet an AOX level in the effluent, but the level is now lower that 0.2 kg/ADT.

The original bleach plant produces 350 mtpd of standard (i.e. bleached using chlorine) pulp using an O C/D EopD sequence, with a minimum of 30% chlorine substitution in the C/D stage. All of the standard pulp produced is used internally, with 250 tpd sent to the paper mill and 100 mtpd sent to the wet lap pulp machine for use by three other VCP mills.

The new No. 2, or B line, can swing between ECF, its major grade, or over to TCF as required. The ECF sequence is O(OP)ZD, while for TCF pulps the chlorine dioxide stage is replaced and the bleach plant runs a O(OP) Z(PO) stage. The new line has a pressurized peroxide stage; ozone is applied by an "over the fence" plant. Current use is at a 5 kg/ton rate, for both ECT and TCF pulp grades, with oxygen use is at 18 kg/adt. Peroxide use was initially running about 2 kg/ton but has been reduced based on operational experience.

A project that will be implemented soon will improve the ability to move the bleaching sequence between TCF and ECF modes. Currently, in order to switch from ECF to TCF the mill would need to switch to another tower. For ECF pulps, as noted, a D stage follows the ozone stage. For TCF pulps a switch must be made to another tower for the PO stage.

With the modifications planned, the mill will simply be able to drop out the chlorine dioxide tower. The changes mainly involve installation of additional piping, but they will also improve stability and increase throughput (partially by eliminating the time needed to switch towers).

Wood supply for the mill is currently 75% based on company-owned land. Seventy percent of the wood arriving at the mill is debarked, leaving 30% requiring debarking. Most of the wood comes from within an 80-km radius of the mill, with some coming from south of the state. If capacity is increased to 2000 mtpd the mill will need to pull in wood from these more remote locations.

Two major species of eucalyptus are used and the company utilizes cloning techniques to specialize the trees for the major variations in terrain. Different types are used for low valley terrain and higher hill top terrain. The company continues to work on its forestry operations in order to increase yield and improve fiber properties.

Papermill upgrade. In addition to the major investment in the pulp mill and recovery/utilities, the paper mill has also been upgraded. The overall strategy for the mill is to move away from relying on uncoated commodity grades toward value-added coated papers. The 250 mtpd of paper production includes 100%-eucalyptus based coated woodfree.

Point of addition for ozone in bleach plant.

The mill's paper machine, about 20 years old, was upgraded in order to accommodate this, and to supply high-quality base stock for coating. A new off-machine coater (Voith Sulzer) was added in 1996 to move the mill into coated paper production. Recently the coater was also modified via addition of two Voith soft-calenders on the coater. Also, new Bielomatic sheeters and a new ream wrapping line were added. Control of the basestock for the coater was upgraded with a new Measurex CD control system on the paper machine for basis weight, moisture and caliper, and an Ulma hole-detection system was installed. Also, as part of adding the coater, a 4-stage pressurized cleaning system was added at the paper machine wet end.

Future Plans. A feasibility study is currently being conducted on an expansion of pulping capacity to 2000 mtpd, with a decision on whether to go forward expected by 1999. The next phase is envisioned as expanding capacity of the existing digester which can be readily increased via changes in chip feeding. The project will encompass some major changes in mill layout, such as the relocation of the woodyard. If the project is approved, its envisioned completion date would be 40 months away, or in 2002. The expansion would involve use of the old limekiln (now shut down), expansion of causticizing, a new recovery boiler, a new evaporator plant and an additional pulp dryer.

In the paper mill, the longer-term plan is to further increase coated paper capacity. The 4.2m paper machine feeds a 2.1m-wide coater. Thus, among the options for consideration is the possible addition of another 2.1m coater, or possibly a 4.2m wide coater.

70% of wood is supplied within 80 km of the mill

PROFILE: VOTORANTIM. VCP has two pulp and five paper mills in Brazil. This includes two large mills, Jacarei and Luiz Antonio, each having a 1000 mtpd or larger pulp mill. The Luiz Antonio mill produces 800 mtpd of commodity uncoated papers (mainly cut-size and similar papers). Jacarei produces 250 mtpd of paper, including coated grades, following the 1996 installation of a new coater. The Piracicaba mill makes products including specialty-coated grades such as thermal and carbonless papers. The Moji das Cruzes mill is a small 80-mtpd industrial and specialty paper unit while the Salto mill makes 100 mtpd of specialty grades (security grades). There are currently no plans for a major addition to papermaking capacity via a new paper machine.

The company's focus is on printing and writing grades, pulp and specialty papers. Pulp capacity in 1999 is estimated to be 800,000 tpy, and will reach 1,000,000 tpy following the expected new expansion. Paper capacity is being incrementally increased from 560,00 tpy in 1997 to 600,000 tpy in 1999. It's the number four pulp producer in Brazil behind Aracruz, Klabin and Suzano, but its hardwood capacity ranks number three (Klabin produces significant softwood).

The Votorantim Group is Brazil's largest private industrial group. It concentrates on three major industrial sectors: cement and lime, pulp and paper and mining and metallurgy. Under the pulp and paper group, it produces pulp, uncoated woodfree, coated woodfree and specialty papers (carbonless, thermal and security papers).