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P.W. Gri ffi n et al.
the manufacture of single or multi-ply grades of paper, and is capable of extremely high operating speeds. The contemporary paper industry is a relatively high technology sector that takes full advantage to modern developments in electronics and Information and Communications Tech- nology (ICT), such as for the automatic control and monitoring of paper- making plants [19]. Wood-pulp for the British industry is now typically produced from resources obtained via the timber industries in Canada and Scandinavia, as well as from Scotland [15]. The UK paper sector has continued to innovate and has invested heavily, for example, in a modern newsprint machine (producing 400,000 tonnes of newsprint per year) and £300 M in a state-of-the-art containerboard machine to produce lightweight paper [19]. The consumption of paper and board products in the UK amounted to just over 10.5 Mt in 2010 (the baseline year for the present study) according to the national trade association: the Confederation of Paper Industries (CPI) [20]. There was a modest decline of some 2% per annum thereafter. Corrugated paper demand corresponded to around 2.15 Mt in 2010, which has risen modestly in recent years (to ∼ 2.3Mt in 2015) [20]. These demands were met with the aid of 3.8 Mt of re- covered or recycled paper in the base year. Indigenous production of paper and board was about 4.3 Mt in 2010 from just over 50 paper mills of varying sizes and specialisms [20] (having ∼ 9000 employees). Parent reel tissue production was only around 730 kt. These mills uti- lised 1.1 Mt of wood-pulp (0.9 Mt from indigenous sources and 0.2 Mt imported), as well as sawmill residues, like wood chips [20]. Timber extracted in the UK for pulp and paper production amounts to less than 5%, and comes typically via virgin wood fi bre from sustainably man- aged and certi fi ed forests [19]. Recovered paper has steadily increased since the 1950 s [19] to the current level of 3.75 Mt. Indeed, the British paper industry has a recycling rate of ∼ 80% (collected from both households and businesses), which is the highest of any material. However, there are constraints on the quantity of paper fi bre that can be recycled [19]. Around only 19% is not recyclable, because (i) it increasingly degrades as it is goes through successive recycling phases (up to about a maximum of 7 times, although in Europe it now stands at 3.4 cycles); (ii) it is kept embodied in artistic works, books, photographs or wall paper; or (iii) it disintegrates when used in the form of cigarette or sanitary papers [19]. The UK was a signi fi cant exporter of recovered paper amounting to some 4.3 Mt that went to China ( ∼ 75%), the European Union (EU) ( ∼ 14%), India ( ∼ 5%), Indonesia ( ∼ 3%), and the Rest of the World ( ∼ 3%) [20]. This helps reduce ‘ carbon footprints ’ of paper-making elsewhere around the world. Fuel consumption in the UK paper and board sector is dominated by boiler and combined heat and power (CHP) or co-generation plants for process electricity and steam production. Energy is required to drive machinery and to generate heat to dry the paper produced [19]. Fuel demands are mostly met by natural gas (NG), although biomass is in- creasingly being utilised and presently accounts for about 15% of sector
Fig. 3. Greenhouse gas (GHG) emissions from UK industry. Source: adapted from Gri ffi n et al. [7].
Signi fi cant innovations in paper-making accompanied the so-called Industrial Revolution in the UK from about 1760 CE onwards [11,14,15] accompanying, for example, the discovery of ways of bulk-producing acids and alkalis. Such developments came about from a fusion of empirical ‘ rules of thumb ’ with the basic sciences [12]. The fi rst steam engine to drive a paper mill was installed at Wilmington near Hull in about 1786, and there were several steam-powered mills located in various parts of Britain by 1815 [17]. Machines to make paper on an endless ‘ web ’ (similar to that patented by John Gamble in 1801) were built by the London inventor and engineer Bryan Donkin [17] in 1804 in order to replace the earlier batch type of process [11]. Pulp was poured onto a moving web (belt or cylindrical drum) from which it was drawn out as a continuous sheet, and then dried on rollers [15]. Var- iants of this design were installed by Henry and Sealy Fourdrinier in paper mills that continuously produced paper or board at Two Waters and Frogmore in Hertfordshire, and at St Neots in Huntingdonshire (see Fig. 4 [18]). Donkin subsequently developed a rotating type bed that came into practice in 1813 [17], and which further increased the speed of printing [14]. A dramatic rise in the reading public in the latter half of the 19th Century led to a signi fi cant increase in the consumption of paper, even before the excise duty was abolished in 1861 [14]. The provision of the fi rst municipal libraries in Britain around 1850 gen- erated interest in books and, after the newspaper tax was repealed (in 1855), the number of newspapers trebled in forty years [14]. This de- mand could not be met from linen and cotton rags and straw, and Esparto grass from Spain and North Africa began to be imported [14]. However, the real solution to this problem was the use of wood-pulp, which progressively replaced rags with cellulose fi bre from coniferous trees [11,14]. The pulp was initially prepared by using grindstones immersed in water containing ready-cut logs. But this did not remove detrimental resin and other impurities, and from 1873 onwards che- mical wood-pulp was employed by boiling wood chips with soda or sulphite solutions. This provided most of the input material for the great rolls needed by the emergent newspaper industry [14].
2.2. Structure of the modern pulp and paper sector
A modern paper-making machine is usually an enhanced version of the Fourdrinier type [11] (see again Fig. 4), which uses a specially woven plastic fabric mesh conveyor belt that is often several hundred metres long. The proportion of the machine involved in removing water from the web either by drainage or steam represents over 90% of the total length [11]. The speed at which paper, and more particularly multi-layer boards can be produced is determined by the rate at which the water can be removed from the webs [11]. An innovative devel- opment in the early 1960 s was the ‘ Inverform ’ machine in which water is removed under gravity from below and with the aid of a vacuum box from above the webs [11]. This paper-making device can be used for
Fig. 4. The traditional Fourdrinier paper-making machine of the type built by Bryan Donkin. Source: adapted from the University of Michigan, 1920 [18].
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