Lignin Charcoal

Pyrolysis has a long history in the upgrading of biomass. The dry distillation of hardwood was applied in the early 1990s to produce organic intermediates (methanol and acetic acid), charcoal and fuel gas [3]. Today s processes can be tuned to form char, oil and/or gas, all depending on the temperature and reaction time, from 300 °C and hours, to 400-500 °C and seconds-minutes, to >700 °C and a fraction of a second [3, 19, 23, 24], The process is typically carried out under inert atmosphere. We illustrate the basic chemistry of pyrolysis by focusing on the conversion of the carbohydrate components (Fig. 2.4). The reaction of the lignin will not be covered here but should obviously be considered in a real process. Interested readers could consult the literature, e.g., [25]. Pyrolysis is discussed in more details elsewhere in this book [26],... 

Weber Powder. Prepd by mixing either NC and K chlorate or Nitro Lignin and charcoal with oil Ref Daniel (1902), 803... 

Other black substances are occasionally employed. Charcoal from various sources, when reduced to an impalpable powder, and mixed with the other ingredients, furnishes a deep blue-black ink that dries rapidly. Carbonized vine-stalks, wine-lies, woods of various kinds—in fact, carbonized lignin from any source, when ground sufficiently fine—sometimes a tedious and costly operation—answer well as also does bone-black. The brown tint possessed by lamp-black is not (infrequently neutralized by the addition of blue compounds, 3B indigo, Prussian blue, et cetera. 

Encouraged by the success of the hydrogenolysis of aspenwood meal this approach to lignin study w.as continued in these laboratories. Special attention was given to the effect of adding acid or base and to the use of palladium-charcoal as a catalyst on the products of hydrogenation of both aspen- and sprucewood meals. 

The most significant conclusion that may be drawn from these results is that palladium-charcoal exhibits similar catalytic properties as does Raney nickel if used under similar conditions. The same types of lignin hydrogenolysis products are obtained, and as before the major fraction under neutral conditions is the phenylpropanol derivative, dihydro-coniferyl alcohol. With a minimum temperature ca. 150°C. required for any reaction to occur and an optimum temperature ca. 195°C. for maxi-... 

Pepper JM, Supathna P (1978) Lignin and related compounds VII A study of variables affecting the hydrogenolysis of spruce wood lignin using a rhodium-on-charcoal catalyst Can J Chem 56 899-902... 

The decomposition of lignin into aromatic repeat units is a long practiced art that reached its zenith around 1800 a.d. Production of chemicals by wood pyrolysis was extensively practiced until, between 1750 and 1850 a.d., coal slowly displaced wood as the major chemical source available to man. Wood is usually pyrolyzed at 260-4 lO C and lignin at 300-440 C to produce 50 wt % charcoal, 10-15% tar, and lesser amounts of 2-propanone, ethanoic acid, and methanol [16-181. The tar is often called wood creosote and is a complex mixture of substituted phenols and aromatics. It contains phenol, 2- and 4-methylphenol, 2,4-dimethylphenol, 2-methoxyphenol, 4-methyl-2-methoxyphenol, and 4-ethyl-2-methoxyphenol [19]. 

Overall thermal recovery can he enhanced by cogeneration and advanced technologies such as fluidised bed combustion with fuel pre-drying (6, 7). Useful heat conversion efficiency as a performance characteristic has been evaluated for small boilers using wood fuels, which adopted a combustion equation based on oxidation of lignin, cellulose and hemicelluloses including the effect of air, moisture content and the charcoal fraction in the ash (8). 

The relative portion of arsenic in wood charcoal was over 75 %, and independent of temperature up to 450 °C. It decreased markedly to 60 % at 500 C. The total pyrolysis time caused no significant difference at temperatures between 350 and 450 °C. It is believed that arsenic is strongly bound to cellulose and lignin [1] The decomposition of both chemical components occurs as temperature or the total pyrolysis time increase, resulting in more arsenic compounds being released The combination of a temperature between 350 and 450 C and total pyrolysis time of 200 s and lower is optimal for maintaining arsenic in the wood charcoal under these experimental conditions. 

Dipolar dephasing has been investigated as a means for quantitatively differentiating protonated and non-protonated and molecularly mobile and rigid components in soil organic matter. Cellulose, hemicelluloses, lignin, a protein, chitin, charcoal, palmitic acid and two waxes have been used as model systems for components of soil organic matter. 

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