Charcoal “Mines” in the Norwegian Woods

Abstract

ABSTRACT:This paper reviews lab-scale flash carbonization experiments under elevated pressure using Norwegian wood as a feedstock. Norway's silicon and ferrosilicon industry has been urged to reduce fossil CO 2 emissions by increasing the use of charcoal as a substitute for coal and coke in the reduction process. As charcoal is not produced in Norway, large amounts of it are imported from South-Asia. Norway now intends to produce charcoal locally using optimum carbonization techniques from local biomass and forestry waste. That is where the pressurized flash carbonization experiments come in. Birch, spruce and forest residue or GROT samples (GRener Og Topper, i.e. branches and tops) were carbonized, enabling the analysis of the impact of pressure and FC canister insulation on their respective fixed carbon yields. Forest residue (FR) proved to be proper to make charcoal, as fixed carbon contents of 80% could be achieved at moderate pressures. The fixed carbon yields of spruce and birch wood reached over 90% of their theoretical values. The high charcoal yields can result in remarkable cost savings for the metallurgical industry, while at the same time making excessive deforestation unnecessary. The use of coal will soon be abandoned and charcoal 'mines' could become an obvious choice. 1.IntroductionBecause of the increasing demand for (Si-based) solar panels, for computer chips (following Moore's law) and for silicon for the massive metal production of countries like China 1 , the demand for silicon alloys and other ferroalloys has never been higher. The metal and alloy industry heavily depends on coal as a raw product. In electric arc furnaces, coal acts as a reductant and a carbon source, while in the older blast furnaces coal also acts as an energy source.These industries will not face raw silicon shortages, because over 25% of the earth's crust consists of this element, usually found in the form of silica SiO 2 . However, justifying the use of coal as a raw product in the manufacturing process of computer chips, photovoltaic panels and other metal commodities will pose a problem, especially with changing climate change policies.There are not many substitutes for coal, but charcoal is one. Charcoal has low ash and sulfur content compared to coal, while still maintaining high SiO reactivity, which makes charcoal

Characterization and reactivity of charcoal from high temperature pyrolysis (800–1600 °C)

“…There are different types of wood that can be converted into charcoal, of which wood residuals, consisting of limbs, tops, and stems are especially promising candidates for the use as carbonaceous reductants in ferroalloy industries because of low cost and high abundance [6]. The most important properties of the carbonaceous reductant are high reactivity, high conversion and low levels of impurities (such as sulphur and phosphorus) [7].…”

The effect of feedstock origin and temperature on the structure and reactivity of char from pyrolysis at 1300–2800 °C

“…In recent years, many studies investigated production and/or co-production of carbonaceous solids by pyrolysis treatment of wide variety of renewable feedstocks [3,5,[7][8][9][10][11]. In comparison with the metallurgical coke traditionally used in ferroalloy production, carbon produced from renewable feedstocks contains less fixed carbon and a greater percentage of volatile components and may need to be graphitized prior to use as a reductant [11].…”

Study on the effects of using a carbon dioxide atmosphere on the properties of vine shoots-derived biochar

“…Particularly interesting are the results obtained at the Hawaii Natural Energy Institute (University of Hawaii at Manoa, USA), where a Flash Carbonization (FC) system was used to carbonize a number of agricultural residues. Using the FC process, which employs air in a downdraft reactor to force the flame to move upward through the feed, the researchers from the Hawaii Natural Energy Institute have recently reported very high biochar and fixed-carbon yields at pressures of 2.17 MPa [14].…”