The Sappi Ngodwana pulp-and-paper mill in Mpumalanga consists of four distinguishable parts, Engineering News has been informed in an exclusive presentation at the large forest-products operation.

These are the pulp mill, the paper mill, the utilities plant and the chemicals plant.

In the pulp mill, cellulose fibre is extracted from wood and in the paper mill, newsprint and kraft linerboard are produced from the pulp. Ngodwana newsprint is manufactured using primarily mechanical pulp, also known as ground wood.

The utilities plant generates steam and electricity used by the self-sufficient mill and the chemicals plant regenerates the chemicals used in the pulping process.

From an organisational point of view, the mill is divided into only two parts, namely the pulp mill and the paper mill.

The pulp mill encompasses two digesters, utilities and chemicals plants and the paper mill is a mechanical pulp plant with two paper machines, one a newsprint machine using the mechanical pulp and the other a kraft linerboard machine using chemical kraft pulp and a relatively small volume of recycled fibre.

Only a decade ago, the Ngodwana-owning company Sappi was a purely South African company.

However, as a result of the implementation of international strategies, Sappi is today a global company with twenty mills on the three continents of Africa, Europe and North America and customers in more than a hundred countries.

The Ngodwana mill, situated in South Africa’s Mpumalanga province, is one of the larger of Sappi’s Southern African operations. Being able to run ahead of the competititon has been brought about by Kraft’s commitment to technological innovation, quality and service delivery, Sappi Kraft operations director Allen Young, tells Engineering News.

These core values have steered the Ngodwana mill to prominence ever since 1966,when the first reel of pulp was produced, Young says. Much of what Ngodwana is today is the result of a major mill expansion that took place between 1981 and 1985, forming the basis of its selection at the time, by the way, as an Engineering News Project of the Year.

To ensure ongoing modernisation, a project development department was established in 2000.

This department is led by John Moon, who tells Engineering News that Ngodwana is currently in the process of implementing a R400-million capital expenditure programme (see also fuller story on page 33 of this edition). He reports that continual investment in the modernisation of production processes has resulted in high levels of efficiency being attained at Ngodwana Today this kraft mill has a capacity to produce approximately 235 000 t of linerboard and 140 000 t of newsprint a year. The linerboard machine also produces approximately 34 000 t of white top liner per annum (included in total linerboard capacity). The mill is a low-cost producer and is a net seller of pulp. It produces nearly 410 000 t of bleached and unbleached pulp and 100 000 t of groundwood (mechnical) pulp annually. The mill markets paper and excess pulp locally and in the export market. The mill is a large consumer of waste paper, which is used in the production of packaging paper.

Numerous by-products, including tar and bark, are also separated and sold.

The mill’s activities begin at the woodyard, where timber is received in both log and chip form, 2,4 m logs being debarked and then chipped and stored on large chip piles.

Hardwood, softwood and sawmill chips are separated in different piles, with fines and oversize material removed prior to pulping.

The chips are transported on belt conveyors to the two fibre lines.

Fibre line one was upgraded to peak standards in 1995 and produces mainly high-yield unbleached softwood pulp in the form of noodles, used exclusively on the kraft linerboard machine. Fibre line two produces both bleached and unbleached pulp.

The bleach plant uses high-consistency oxygen and ozone bleaching technology, the primary bleaching agent, chlorine dioxide, being produced on site.

Both fibre lines are supported by a kraft chemicals recovery facility, which recovers chemical liquor from the digesters and converts inorganic chemicals into an active form for reuse.

The high-quality newsprint produced is supplied to the newspaper publishing industry and kraft linerboard and white top linerboard to the packaging industry.

Self-sufficiency is high on Ngodwana’s priority list, water serving as a good example.

Thirty-five million litres of water are supplied a day from the company’s own dam on the Ngodwana river.

An integrated water circuit system recycles water for repeated reuse, which limits consumption and the generation of effluent.

Some 27-million litres of effluent are processed a day at a purification plant and used for adjacent farm irrigation. Thirteen years ago, stormwater ponds were installed, preventing process water from returning to the river directly through the stormwater system prior to being treated in the ponds.

Operations at the Ngodwana mill are of the heavy industrial kind, posing many inherent dangers to employees, contractors and visitors if caution is not exercised, which is why the operation puts much emphasis on safety, with all employees and contractors undergoing a safety, health and environmental induction programme before entering the mill.

Refresher exercises in personal safety, emergency preparedness, environmental protection and quality assurance are undertaken yearly.

Ngodwana has its own emergency services unit, which is supported by a well-equipped medical centre to ensure quick response and care in the event of injuries occurring.

Protection of the environment is very high on Ngodwana’s agenda, and rightly so, given that its activities involve emissions of particles into the atmosphere, the generation of odorous gases, the use of chemicals and the release of substantial effluent.

As proof of its commitment to environmental protection, Ngodwana is the holder of an International Standards Organisation 1401 certificate, coupled to its investment in best available environmental technology, including electrostatic precipitators, odour- control systems, water and solids waste recycling processes and equipment to monitor environmental faults.

Moreover, it has spent R200-million on environmental protection in the past 13 years.

Ngodwana also sees itself as being conscientious in the area of corporate social investment and supports neighbouring communities in the fields of education, job creation and through HIV-Aids awareness programmes, as also takes place at the group’s other mills at Usutu, in Swaziland, at Tugela, Stanger and Sappi Saiccor, in Kwazulu-Natal, at Cape Kraft, in Cape Town, Enstra, in Gauteng, and Adamas, in Port Elizabeth.

The first fibre line was installed at Ngodwana in 1966 to produce only unbleached pulp, which was sent to Enstra for conversion into paper.

Paper machines were added to this pioneering fibre line in 1972. The second fibre line was commissioned in 1984, and the kraft linerboard machine installed a year later.

Two turbines with a combined output of 117 MW were installed in the late Eighties and ozone bleaching technology and high-yield pulping technology was introduced in 1996. Ngodwana generates 780 t of steam an hour and the mill consumes 35 megalitres of water a day.

Ndogwana consumes 2,2-million tons of wood a year, two million tons being pine (softwood) and the rest being gum (hardwood).

Some 600 000 t of coal, the bulk of it from the black-owned company Eyesizwe, South Africa’s fourth- largest coal company.

In 1994, an ozone plant was installed at a cost of R76-million.

In 2000, electrostatic precipitators P1 and P2 were retrofitted at a cost of R23-million and P4 the next year at a cost of R16-million.

Equipment installed since the start of the new millennium includes an emissions and particulate monitor, a R14-million lime-kiln precipitator, a R9-million upgrade to a low-volume, high-concentration gases system and the recently-retrofitted P3 electrostatic precipitator at a capital cost of R21-million.

In the process of being retrofitted is the P5 electrostatic precipitator at the same capital cost (see also story on page 54), taking total expenditure on mitigating the mill’s environmental impact in the past 13 years to more than R200-million.

Ngodwana has 1 180 employees and supports 18 000 people indirectly through this employment.