In common with many companies now involved in the Chinese MDF industry, Suichang Luyuan Wood Co Ltd started out with a wet-process hardboard line in Suichang County.
That was back in 1985. Ten years later, the company built its first MDF line, using a 15-daylight Shanghai Wood Based Panel Machinery Co Ltd press. It followed this with another two lines of similar size from the same supplier, one in 1996 and one in 1997.
These three lines gave the company a total annual capacity of around 150,000m3. Like many other Chinese MDF producers, Suichang Luyuan realised that, if it was to be truly competitive going forward, it needed to build a European-made continuous press line.
The company then bought a Greenfield site in a newly established industrial area in Suichang County in an area of wooded mountains in Zhejiang Province close to China’s eastern seaboard. The name Luyuan, literally translated, means ‘green source’.
The next step was to place the contract for the new MDF line and Suichang Luyuan chose Siempelkamp as the main contractor to supply the press line, while Siempelkamp’s subsidiary, Sicoplan, had the coordinating function, designing the plant layout and controlling the interfaces between the various items of equipment. The front end of the line was a separate contract for Andritz, while Steinemann had a separate contract for the sanding, and Anthon for the cut-to-size plant. Civil works began on the site in March 2003 and the project was completed by November of that year. The first board was produced on December 10, 2003, only nine months after the first hole was dug.
As the new continuous line came into production, Luyuan sold one of its three multi-daylight lines and moved the other two to new locations in the neighbouring county.
Those two lines are rated at 100,000m3 a year in total and the new Siempelkamp ContiRoll line adds another 150,000m3 at full capacity.
But that is not the whole story. The Suichang company is part of the larger Luyuan Group, headquartered in Hangzhou City, Anhui Province, which has 10 branch factories and a total of 11 MDF production lines in different provinces of China, mainly to the south of the Yangtse river. All the factories were built new by the group, rather than being purchased as going concerns.
Total production capacity for the group today is around 700 to 800,000m3 a year, although 2003 saw a total production of 480,000m3, because only seven of the lines were in production at that time.
The company claims to be number one in China in terms of capacity, although Mr Guan Qe Qin, general manager of Suichang and a vice-president of the company, admits that that is a fluid situation in China’s fastgrowing MDF industry.
What he is sure of is the fact that, in Suichang County, Suichang Luyuan is number three in output value for all industrial enterprises.
The well-stocked woodyard holds the pine and mixed hardwood logs, mainly in the form of branches and other small diameter roundwood. Sawmill residues are used only for fuel.
A log grab feeds the roundwood to a locally-made drum debarker from which the bark is conveyed to the fuel storage area.
The chipping line was supplied by Andritz Oy of Finland, utilising an Andritz Oy HQ-chipper while the refiner, from Andritz of Austria, is a 52/54in model. After chipping, the chips are carried by a covered conveyor to a concrete chip silo and then to a locally-made chip screen to remove oversize and fines.
They then travel to the top of the refining building where they are washed thoroughly before entering the refining process.
The dryer came from Büttner of Germany and the gluing system from Imal of Italy, both as part of the Siempelkamp scope of supply. Sifting, forming, pre-press, continuous press, board trimming, cooling and stacking were all supplied by Siempelkamp, with subsidiary SHS supplying the latter components.
With thin board running at high speed, the roller conveyor is an important component to avoid the board jumping as it comes out of the press and so SHS supplied these components which might otherwise have been supplied locally.
All on-the-line quality control and monitoring systems were supplied as part of the same contract, as was the bag filter and fibre transport system for the forming station. The forming line has no scalping, leading to reduced operator cost because there is no need for a vacuum transport system to remove the scalped fibre. The scalping function in this ‘Starformer’ has been replaced by an equalising roller to give even distribution of the mat.
It also removes the problems of pre-cure of the resin during recirculation – possibly several times in a conventional, scalped system.
There is a Weko mat damping unit before the press.
“This is the fastest line in China, capable of running at 1300mm per second,said Mrs Ma Hangqing, manager with Siempelkamp’s Beijing office. “Even when making 2mm board, it can produce 700m3 a day of very good quality, flat boards.”
The ContiRoll press is housed in an enclosure to trap and extract fumes and is 23.6m long and eight feet wide. It is equipped with a flexible infeed enabling it to quickly achieve high-speed production.
To achieve this flexibility, both platens are 60mm thick at the infeed, rather than the normal 100mm, and the radius of curvature can be adjusted in the plus or minus direction. The principle is to achieve a fast pressure increase in order to produce thin board at high speed without incurring blisters due to trapped air in the mat. Pressure can, in fact, be varied along the infeed section in a pressure ‘wave’, if required, explained Mrs Ma.
A variable position infeed conveyor also facilitates this process, going further into the press opening when thinner board is being pressed. This is in order to position the mat in exactly the right place so that it receives heat and pressure equally on both sides simultaneously, thus avoiding pre-cure of the resin on one side – a potential problem if one side of the mat touches the hot belt before the other.
Boards exit the press to go to two star coolers before being taken to intermediate storage.
A Steinemann Satos eight-head sander is available for panel sanding and there is an Anthon angular cut-to-size plant which takes books of up to 60 panels of 2.5mm thickness.
The central control room is conveniently located between the main production line and the refiner room, with windows on each side of the control room giving a clear view of either area to supplement the comprehensive computer real-time graphics and the CCTV monitors.
The region has a stable supply of electrical power, generated by hydro-electric power stations, said Mr Guan.
Energy for the MDF production line is generated by a GTS Energy plant supplying steam, thermal oil heating and the flue gas for drying. This American based company has had some success in supplying energy plants for the new wave of MDF lines in China, beating some strong European competition.
Process water is treated in a biochemical system to meet Chinese water quality standards, and much of it is recycled into the MDF production process.
Exhaust air is filtered in a bag filter system which is a mix of locally-made and imported equipment.
New mills in China attach increasing importance to quality control and to protecting their considerable investment. Suichang Luyuan chose GreCon as the supplier for both on-the-line quality control, with density and thickness measurement systems, weight-per-unit-area gauges and blister detection; and for spark detection and extinguishing systems throughout the plant.
The new Siempelkamp line has given Suichang Luyuan a whole new market area on which to concentrate. The old multi-daylight lines were only able to produce 9mm and thicker boards, but the new line adds thinner panels to the range.
Thus the group now offers thicknesses of 2.5, 2.7, 3.0, 4.0, 5.0, 6.0, 8.0, 12.0, 15.0 and 25mm panels. Around 80 to 90% of production from the new continuous line is under 6mm thickness.
Densities offered are 820-860kg/m3 for 12mm and 15mm board, 760kg/m3 for 18mm and thicker and 860-880kg/m3 for thin board.
The principle resin used is urea formaldehyde (UF), but for grade one board, melamine urea formaldehyde (MUF) resin is used to produce a moisture resistant E1 grade.
Currently, Luyuan only supplies the domestic market, all over China, with the main customers being engaged in the furniture industry, domestic decoration and some high-grade packaging of consumer products.
“At present we just manufacture raw MDF board, but in future we will maybe add some downstream products,said Mr Guan.
An advantage for MDF in China is that it is exempt from the normal 17% VAT because it uses ‘waste’ wood, explained Mrs Ma. By waste in this context, she means branches, small diameter and crooked logs, forest thinnings and so on. In other words, wood that is not usable for lumber.
Larger logs incur VAT and this could be one obstacle to the development of an OSB industry based on fresh wood in China.
The limiting factor on MDF production in China is always the availability of wood to make the fibre but Mr Guan is confident that his factory faces no such problems in an unusually well-wooded region.
“We selected this area for the new factory because of the raw material supply and I don’t see any problem,he said. “This is a mountainous area with plenty of wood, mostly from natural forest and some from plantations. The rainfall in this area is high and trees grow well by natural regeneration.”