Technological Change in the Pulp and Paper Industry: A Network Approach
...d experienced locally; 3) Technological development is an accumulative process. This last point is especially interesting. In this connection, we can read: “The network creates limitation and opportunities, a momentum, pushing the technological development in the direction set by the past.” (Lundgren, 1994, Håkansson, 1989). Companies never act independently; they are always stationary, embedded in a surrounding. This surrounding sets the boundary for what the company can do; it is limiting while at the same time it makes change possible. Closely related to the network approach are the “technological systems” described by Hughes (1987, 1994). In technological systems components interact with each other. These components all contribute, directly or indirectly via other components, to a common “system goal”. If a component is taken away from the system or if its characteristics are changed, the characteristics of the remaining artefacts in the system will change accordingly. Hughes views industrial enterprise as a phenomenon that occurs within the framework of technological systems. He speaks of interfaces within activities that occur within the systems. The fact that raw materials are refined in machine equipment, manufactured by many different companies and distributed through several companies, makes the task of understanding and tracing the various influencing factors in the whole production chain extremely complex. The input-output process in a technological system is described thus: “A technological system has inputs and outputs. Often these can be subsumed under a general heading...Within the system the subsystems are linked by internal inputs and outputs, or...interfaces” (Hughes, 1994). In these interfaces, different companies and technologies meet, i.e. products from different companies interact in refining a raw material. Thus, the production system of a related company is decisive in judging how a particular company’s input or equipment can be utilised efficiently. Hughes (1994) points out that systems that have reached a certain level of maturity reach a certain kind of momentum and that these mature systems have qualities that can be called “sluggish”. Other concepts related to momentum are vested interests, fixed assets, and sunk costs (Ibid). Lundgren (1994, p. 75) regards technological systems and industrial networks as “generic concepts covering the same ground. The concepts are not mutually exclusive and in many cases they are interchangeable.” Lundgren uses the concept of industrial networks to describe both technological systems and actors’ networks: “Thus it is the interplay between technological systems and networks of interrelated firms that begets the evolution of industrial networks.” (ibid., p. 77). THE THERMO PULP CASE STUDY In recent years, the forest industry has given greater priority than earlier to the problem of high electric-energy consumption in mechanical pulp processing. This problem is by no means new to refiner manufacturers. It is considered a “classic” problem within the paper industry and the equipment supply firms. Now, however, the high consumption rate has become especially interesting, partly because of the increased prices that a shutdown of nuclear power plants in Sweden will entail, and partly because the technology to produce newspaper paper made from recycled fibres has been so successful that there is now a cost-effective alternative to the fresh-fiber thermo pulp process. Pulp made from recycled fibres requires only 500 kWh/h, whereas TMP requires an electric output of about 2,500 kWh/h to attain high quality pulp (Höglund et. al., 1996). Since 1870 , the paper industry has been making newspaper paper from ground pulp, which is wooden logs that have been crushed against a grindstone. In order for the paper to have a certain level of strength, 25% chemical pulp in the form of sulphite cellulose was added. This was the predominant process for newspaper paper until the end of the 1960s. Toward the end of the 1970s, the environment groups started to realise how dangerous sulphite cellulose was. The sulphite cellulose factories of the newspaper paper mills were hurriedly shut down. Sulphite cellulose is still being produced at a number of production sites in Sweden, however not for news paper paper. Parallel to this development, a new technique was introduced that made it easier to phase out the sulphite factories—the so-called thermomechanical pulp process (TMP). TMP, developed by American and Scandinavian (Swedish) companies, was advantageous because it produced a pulp consisting of long fibres that were so strong that chemical reinforcement pulp could be completely excluded. TMP development did not occur overnight, however. The first TMP applications for newspaper paper began to be used in the mid-1950s, but it was not until the mid-70s that there were paper machines being fed only with TMP. At about the same time, paper machines themselves were also being further developed. Their speed was increased through the introduction of such innovations as an upper dewatering wire and the zigzag wire. The increase in speed meant that the demand for pulp strength also increased. To avoid having to mix in sulphate pulp (which has good tensile properties but costs more than TMP and also affect the properties of the end product negatively), efforts are continuously being made to make the thermomechanical pulp stronger instead. The result of these efforts has been a pulp-producing process that consumes a good deal of energy, because processing the wood fibres requires electric energy. This processing is done in a machine similar to a disk crusher and is called a refiner. Today, after a succession of mergers and acquisitions, there are three companies that produce refiners: Sunds Defibrator, Andritz Sprout Bauer, and Kvaerner Hymac. Of these three equipment companies, Sunds Defibrator is the largest supplier of TMP machinery (Bystedt & Peterson, 1988). The TMP process of today The dominant raw material used in the production of TMP is fresh spruce. The second raw material is electric power. Together, the raw wood material and the electric power account for about 90% of the variable production cost of the TMP process. The wood should be fresh because that makes it easier to remove the bark. The wood is taken from the woodyard and put into drum barkers, where it is “de-barked”. A drum barker is a large steel barrel that rotates either horizontally or at a slight angle. Wood lifters and the impact of the logs hitting against each other causes the bark to loosen. The logs are then taken to chipping machines, where the wood is chipped into 15-40 mm long and 6-10 mm thick chips. The chipping machine consists of a rotating chipper disc with a number of cutters against which the logs are chopped. Shavings, chips, and splinters that do not fit the correct dimensions are sorted out. In order to remove sand and other dirt particles that could disturb the process and lower the quality of the pulp, the chips are washed. Then they are heated up to be made soft so that they can later be spread onto the peg screws found in all refiners. The chips are then transported into the refiner’s “pitch screw”, which throws the chips into the refiner at great speed. Well inside the refiner, the wood chips undergo further processing against the machine’s grinding discs as they are slung from the centre into the outer edge of the grinding discs. On the grinding discs are a number of replaceable grinding segments. These have a fluted pattern and consist of “bars” and “dams”. The fiber tufts are caught by the dams and made to float over them, thereby freeing and treating the fibres. It is at this stage in the process that the greater part of the energy is needed, between 2,000 and 2,200 kWh/h. The refining process is often carried out in two steps to further treat the wood fibres. Before the pulp goes to the paper machines, it is filtered and purified and then ground once more in a so-called reject refiner. Depending on the quality of the paper that the pulp is designed for, the process is carried out more or less completely, meaning that the qualities that are processed the longest are those that require the most electric energy during the refiner stage. The surrounding production system The task of the paper machine is to concentrate the pulp and produce a paper that will suit the customer’s manufacturing process, i.e. the printing press. In the paper machine, the pulp is first spread onto a wire section and then concentrated on the wire, press and drying sections. With the speed of a modern paper machine reaching 1,600 - 1,700 meters per minute, the paper’s strength must meet with very high demands. This is especially true for the so-called “free draught” areas in the paper machine, where the paper web hangs freely, without support from the cylinders. Another stage in the process that puts high demands on the strength of the paper while still at the paper mill is in the winder. If there is a break in the paper web in a newspaper paper machine, one hour’s stop is valued as between SEK 50,000 and 70,000. At the paper mill’s customers—the printing houses and the newspaper printers—new demands are set on the paper when in the printing presses. Just as in the paper machines, the paper must cope with the strains that occur when the paper web is pulled at a high speed through four inking devices. If the paper’s tensile properties are too weak, web breaks will occur, and if this happens all too often during a nightshift, it will cause a delay in the publication of the newspaper. And not only are there demands on runnability, the printability of the paper is also of great importance to quality. This quality factor is very important to advertising customers. These factors have led the producers of wood paper, since the breakthrough of the TMP process, to tend to increase the use of electric energy in the refining stage in order to obtain the positive qualities that are obtained when wood chips are ground into pulp. Bigger and bigger refiners have been used, with greater and greater power output. Electricity consumption is central to the entire production system represented by the refining of wood fibres, since it gives the pulp and the paper qualities that are necessary in order for production activities through the whole refinery chain to be carried out efficiently. The paper must cope with many different situations during the refining process, from wood to finished newspaper. At the same time, many presumptive sources of error can be traced in the production, with the manufacturing of pulp occupying a central role for the result of the rest of the process, which emphasises the importance of electrical power. A change in the manufacture of the pulp, especially in the refining process (and its use of electricity)—which represents the “heart” of the pulp production—is a serious intrusion. It is also a production process that involves heavy capital investments, and one where historical investments strongly influence future ones. The development of an energy-efficient pulp process Ever since the thermomechanical pulp process came into use, the builders of refiners have tried to increase the efficiency of the process’s electric-power consumption. The results, however, have only been marginal. The equipment firms have invested in such improvements as developing the grinding patterns of the grinding discs, increasing their number of revolutions, etc. Sweden’s Skogsindustrins Tekniska Forskningsinstitut [Forest Industry’s Technological Research Institute], STFI, has also carried out research in the field of electric power efficiency for the TMP process. For a long time, Sunds Defibrator could take advantage of its standing as the largest manufacturer of refiners and the company with the greatest development resources to make sure that no other company came up with alternative technology for defibrating wood fiber into mechanical pulp. And in fact, the impetus to develop the refining process did not come from a refiner manufacture. Instead, it was the equipment firms working with recycled paper who—in a very short time—developed a process to turn recycled fiber pulp into a high-quality product. This was a serious threat to Sunds Defibrator. After having a Mechanical Pulping Division that stood for 50% of total sales in the late 1980s, this share fell sharply to about 20% during the next few years. This was mostly due to the success of the recycling equipment firms, although the general state of the economy also played a part. One of the advantages of the recycled paper pulp process is that it only requires about 500 kilowatt hours per hour, which is 20% of what the TMP process needs. Sunds Defibrator began to realise the seriousness of the situation, and the desire to develop the TMP process and its large electric-energy consumers, the refiners, was probably very great at this point. However, even though this was an urgent problem for the refiner manufacturer Sunds Defibrator, the idea for a new grinding method came from a customer and not from within Sunds Defibrator. SCA took the initiative Around 1992, the Thermo Pulp project was begun when Svenska Cellulosa AB (SCA) contacted Sunds Defibrator to discuss a possible co-project for developing refining technology. Both companies had personnel in their development divisions with long experience within their branches and in research on mechanical pulp. Through the development work, intensive contacts took place between the two companies’ R&D divisions. An important factor in this co-operation, as pointed out by the people at Sunds Defibrator, was the groups’ mutual background from work at STFI. Also, the geographical closeness and the fact that there have been ownership bands between the two companies were also factors mentioned in the interviews. The formal part of the development was first carried out in the laboratories of Sunds Defibrator to determine parameters for qualities that the finished pulp needs, such as fiber strength, brightness level, etc. The second step in the development process entailed installing a prototype processor in Ortviken, SCA’s paper mill outside Sundsvall. This prototype confirmed the results that had been obtained at the laboratory scale, which were that the same basic fiber quality could be obtained using a lower energy input. This is, however, an official picture; those involved admit that the development process did not really evolve in such a direct and linear manner. For instance, Thermo Pulp had a few teething problems in the beginning in the form of mechanical problems. There was also some resistance to the project from both companies in the beginning, though these were overcome with time. The principle behind Thermo Pulp™ The principle behind the Thermo Pulp process is to use higher temperatures in the second refining stage. For a long time, the forest industry has known about the softening effect of lignin at high temperatures. Above 180°C, lignin softens and the need for mechanical power to make a crack in the wood structure decreases dramatically, which in turn means a reduction in the need for electric power. This technique has been used in producing fiber-board at Sunds Defibrator since the 1930s. Attempts were made to use higher temperatures in the TMP newspaper paper process as well, but were stopped because the pulp had to be blanched after exposure to high temperatures. In addition, the resulting pulp lacked the so-called “fines” that give the paper its scattering qualities (Rindö, 1995). Studies have shown that in two-step refining, it is in the first step that most of the pulp’s properties are determined; the second step influences these properties only marginally. It has also been found that the second refining step can be carried out in many refiners under atmospheric pressure or under pressurised conditions without significantly changing the pulp’s properties. Thermo Pulp’s goal was therefore to obtain the desired pulp properties in the first refining stage, after having pre-warmed the wood chips at 180°, the temperature at which lignin softens. Then, energy-saving measures could be undertaken in the second stage (Höglund et. al., 1996). Restrictions from the surrounding production system Decreasing electric use in the TMP process is no easy game. In effect, all of the projects carried out at Sunds Defibrator and other companies during the past years to make energy consumption more efficient have led to a deterioration in the quality of the pulp, which in turn has had a negative effect on the finished newspaper paper. This applies partly to Thermo Pulp as well. Even though a good amount of the invested energy is converted into heat and steam, “it is apparently the ‘useful’ energy that is reduced and that causes a loss in quality,” as one of the people involved in the Thermo Pulp project put it. For example, Thermo Pulp creates poorer brightness due to the high temperature in the second refining stage. If hydroperoxide must be added, this causes a significant extra cost for the mill that installs a Thermo Pulp line. Moreover, the pulp that comes out of Thermo Pulp has a somewhat different fiber distribution, than conventional TMP, with a higher share of short fibres, which sometimes means that sulphate pulp must be added to meet with the strength demands of paper machines and printing presses. If this turns out to be the case, the entire savings in cost from the reduction in energy consumption may thereby be lost. However, there may be other values in a reduction of energy consumption. One advantage of Thermo Pulp, nonetheless, is that the equipment can be connected to existent surrounding equipment, since only the modification of one process stage, the ...