Cellulose heating value

Wood forms one of the world s most important chemical raw materials. It is the primary source of cellulose for the pulp and paper and cellulose industries. These industries are well up in the group of 10 major industries of the United Slates. For paper, rayon, films, lacquers, explosives and plastics, which comprise the greatest chemical uses of wood, it is the cellulose component (plus certain amounts of hemicellulose) of wood that is of value. The lignin forms a major industrial waste as a by-product of the paper and cellulose industries. Its major use is in its heat value in the recovery of alkaline pulping chemicals. A variety of minor uses for lignin have been developed, such as for the manufacture of vanillin, adhesives, plastics, oil-well drilling compounds and fillers for rubber. 

The SEPAREX system will recover over 90% of the hydrogen at a purity of 96+% for recycle, while increasing the heating value of the fuel gas from -550 BTU/SCF to -950 BTU/SCF. The projected flow rates and gas purities for the membrane separation are shown in Table II. Under the bone-dry feed conditions the cellulose acetate membrane is not affected by HCl. Special materials of construction and adhesives have been used in the fabrication of the spiral-wound elements to ensure their resistance to HCl in the gas streams. 

They modified an existing autoclave and a real-time digital microprocessor control system so that It could be operated In a semi-continuous mode. Various components of MSW were studied In order to obtain meaningful data, not confused by the different thermokinetics of different MSW components. Feedstocks Included wood flour, cardboard, newsprint and rice (starch), as well as the Important model compounds alpha cellulose and lignin. It was found that these MSW components could be converted to liquid oils and a high-heating value residual solid at temperatures of 325 0 to 400 0 and pressures of 1000 psl to 3000 psl. 

The atomic ratios (H/C and 0/C) and the heating value of celluloslc chars indicate that they are very similar to coal. The H/C ratio of cellulose tars (1.73) is comparable to that of No. 2 fuel oil (1.84). Unfortunately, the high oxygen content indicated by the 0/C ratio (0.91 compared to 0.01 for fuel oil) significantly reduces the heating value of the tars. 

Figure 15.7. Heating value and gas yield of gas products from cellulose pyrolysis.

Peat is formed when dead vegetation is saturated with water which prevents the action of aerobic bacteria. Thus, most of the carbon of the cellulosic matter is retained, and with ageing, peat is formed. It accumulates at an average rate of 0.7 mm/year or worldwide at 210 Mt of carbon. Canada (40%) and Russia (36%) have more than 3/4 of the world s peat land (320 Mha or 150 x 10 Mt of carbon). In Russia, peat deposits occupy about 1/10 of the total country s terrain. It is a spongy watery mass when first obtained from the peat bog. Six toimes of dry peat yield about 1 t of fuel. A commercial grade of peat contains about 25% water. Air-dried peat has a heating value of about 16.3 MJ/kg. Peat is rich in bitumens, carbohydrates, and humic acids, and as a chemical source, it can yield waxes, paraffins, resins, and oils. Peat also is a source of pharmaceutical and curative preparations as well as a livestock-feed supplement. 

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