14 March 1996

Root processing done in a

very big way

£60m has been spent on British Sugars Wissington factory. It now boasts the worlds biggest beet throughput. Robert Harris takes a tour

SIZE is everything at the Wissington sugar beet factory in Norfolk, the stream of beet lorries rattling down the approach roads is testimony to that.

They deliver enough roots to satisfy the factorys voracious appetite – 700t/hour of beet, 24 hours a day. That is an average of 1000 lorry loads, tipping 20,000t of beet, which will make 2300t of pure sugar, each day.

Wissingtons hourly throughput is the same as the daily output of the original factory, established in 1927. Several refurbishments raised capacity to 11,000t a day. From 1991 to 1994, £60m was spent on the beet processing plant to increase throughput by a further 35%.

That enabled Wissington to absorb all the old Kings Lynn factorys area as well as some of the now-closed Spalding and Peterborough factories catchment. About 2200 growers, from the north Norfolk coast to the Brecklands, and from Ely across to Peterborough, an area of 1928sq miles, supply the factory.

Bury St Edmunds, York and the West Midlands areas are as big, but none supplies as much beet. Wissington processes 2m tonnes a year from 45000ha (111,150 acres), 23% of BSs total factory throughput. The factory pays growers £80m a year for beet, well over half its total annual running cost.

Although there are bigger factories in Europe, none processes as much sugar, says agricultural manager Mac McMillan. "Whichever way you look at it, we are one of the biggest in the world."

Wissington is split into two sections. The beet processing end takes in roots for the 21-week slicing campaign. All is converted into thick juice in that time. Half is processed immediately, the rest (250,000t) is stored in tanks for processing during the 22 weeks after beet deliveries end.

Four men – two in the control room, and two "rovers" to check equipment – control the factory processes. Thanks to a £2.5m update, automation is the key.

Computers automatically react to information, making fine adjustments to maintain maximum throughput. "The ability to exactly control the process allows us to run such a large factory," says factory manager, Steve Flack. "It just could not be done manually."

More investment is planned. A bigger power plant, driven by a gas turbine and using waste steam, will cost £30m and provide 25MW of electricity for the factory by 1998. Another 50MW will be sold to the national grid. More money will be spent on the animal feed mill, to produce 300,000-500,000t of feed a year.

£60m has been spent on British Sugars Wissington factory. It now boasts the worlds biggest beet throughput. Robert Harris takes a tour

SIZE is everything at the Wissington sugar beet factory in Norfolk, the stream of beet lorries rattling down the approach roads is testimony to that.

They deliver enough roots to satisfy the factorys voracious appetite – 700t/hour of beet, 24 hours a day. That is an average of 1000 lorry loads, tipping 20,000t of beet, which will make 2300t of pure sugar, each day.

Wissingtons hourly throughput is the same as the daily output of the original factory, established in 1927. Several refurbishments raised capacity to 11,000t a day. From 1991 to 1994, £60m was spent on the beet processing plant to increase throughput by a further 35%.

That enabled Wissington to absorb all the old Kings Lynn factorys area as well as some of the now-closed Spalding and Peterborough factories catchment. About 2200 growers, from the north Norfolk coast to the Brecklands, and from Ely across to Peterborough, an area of 1928sq miles, supply the factory.

Bury St Edmunds, York and the West Midlands areas are as big, but none supplies as much beet. Wissington processes 2m tonnes a year from 45000ha (111,150 acres), 23% of BSs total factory throughput. The factory pays growers £80m a year for beet, well over half its total annual running cost.

Although there are bigger factories in Europe, none processes as much sugar, says agricultural manager Mac McMillan. "Whichever way you look at it, we are one of the biggest in the world."

Wissington is split into two sections. The beet processing end takes in roots for the 21-week slicing campaign. All is converted into thick juice in that time. Half is processed immediately, the rest (250,000t) is stored in tanks for processing during the 22 weeks after beet deliveries end.

Four men – two in the control room, and two "rovers" to check equipment – control the factory processes. Thanks to a £2.5m update, automation is the key.

Computers automatically react to information, making fine adjustments to maintain maximum throughput. "The ability to exactly control the process allows us to run such a large factory," says factory manager, Steve Flack. "It just could not be done manually."

More investment is planned. A bigger power plant, driven by a gas turbine and using waste steam, will cost £30m and provide 25MW of electricity for the factory by 1998. Another 50MW will be sold to the national grid. More money will be spent on the animal feed mill, to produce 300,000-500,000t of feed a year.

Beet is chopped through the lowest leaf scar to establish top tare.


What happens to your crops once they leave the farm?As buyers become more demanding a clear understanding of their needs is crucial. Our new series aims to provide just that.

1. After sampling (centre), some lorries go to one of four wash-off points (left). A water cannon sluices beet into a flume, where it is transported to the beet pump. Remaining lorries tip on the 2ha (5-acre) concrete pad, which holds 40,000t of beet. A Volvo L180, operated by contractor Bill Chapman, stacks beet 5m high. At night and weekends it sweeps 700t/hour into a flume to feed the factory.

2 The beet, along with 3500t of water an hour, is pumped by one of two beet pumps into an overhead flume. Stone catchers (pictured) remove 120t of stones a day. The beet then travels through two weed catchers to remove green material and other trash, like string. Beet is then removed from the water and elevated into a 500t buffer hopper.

3 Beet is then shredded in one of six slicers (pictured). The innards are shaped like a waterwheel. The 22 "paddles" each contain nine knife sets (spare sets on right). These scrape roots to form cossettes, or shreds. Sliced beet is then fed into one end of three rotating diffusers, hot water into the other, to extract sugar. Solid remains make 1500t of animal feed pellets a day. Raw juice is purified.

5 The juice is filtered, reducing impurities further. For crystallisation to occur the clear juice has to have a sugar concentration of 80%. It passes through six evaporators, a total of 4ha (10 acres) of heat exchange surface. These boil off 150t/hour of steam, producing thick juice with a sugar content of 65%. Low temperature boiling in a vacuum pan (pictured) drives off more moisture. Seed sugar crystals are then added to pull dissolved sugar out of solution.

4 Limestone cobbles (350t a day) are heated to 1000C (1832F) with coke. Quicklime is formed and added to the raw juice to form slaked lime. CO2 produced in the heating is added, reverting slaked lime to limestone particles, as demonstrated by factory manager, Steve Flack. These precipitate, taking most impurities with them. Lime sludge is stored as pond lime (Limex 45), or pressed lime (Limex 70). Each year 80,000t and 35,000t, respectively, is sold to farmers.

6 After centrifuging, the pure sugar is dried and cooled. 80% is granulated, 10% is castor, and the rest redissolved into liquid sugar. It is distributed to drink and food manufacturers around the country. Coca-Cola is the biggest customer, but Wissington sugar also ends up in several other soft drinks, and biscuits, ice-cream, cakes and jams.