Treating processes furfural

In the acid hydrolysis process (79—81), wood is treated with concentrated or dilute acid solution to produce a lignin-rich residue and a Hquor containing sugars, organic acids, furfural, and other chemicals. The process is adaptable to all species and all forms of wood waste. The Hquor can be concentrated to a molasses for animal feed (82), used as a substrate for fermentation to ethanol or yeast (82), or dehydrated to furfural and levulinic acid (83—86). Attempts have been made to obtain marketable products from the lignin residue (87) rather than using it as a fuel, but currently only carbohydrate-derived products appear practical. 

In order to gain some information about the fundamentals of the hydrothermal carbonization process, the hydrothermal carbonization of different carbohydrates and carbohydrate products was examined [12, 13]. For instance, hydrothermal carbons synthesized from diverse biomass (glucose, xylose, maltose, sucrose, amylopectin, starch) and biomass derivatives (HMF and furfural) were treated under hydrothermal conditions at 180 °C and were analyzed with respect to their chemical and morphological structures by SEM,13 C solid-state NMR and elemental analysis. This was combined with GC-MS experiments on residual liquor solutions to analyze side products... 

The Purdue concepts have been applied to several different agricultural products, such as corn stalks, alfalfa, orchard grass, tall fescue, and sugarcane bagasse. No experiments have been reported on either hardwoods or softwoods. The processes have been explored in two major modes. In the first, the entire agricultural residue is treated with solvent in the second, a dilute acid pretreatment to remove hemicellulose precedes solvent treatment. The first process is especially desirable for making furfural or fermentation products from hemicellulose as a separate activity. Then, the hemicellulose-free raw material can be converted to substantially pure glucose. 

Considering the volatiles that evolve from hot pressing and heat-treating operations, it is concluded that the major chemical changes occurring in this stage are pyrolytic. Methanol, acetic acid, furfural, and ligneous tars are the common volatiles produced by the slow pyrolysis of wood practiced in destructive-distillation processes. The temperatures used in the board conversion operations approach pyrolysis temperatures of wood and the evidence indicates that pyrolysis is indeed active in board conversion. 

In the normal recovery schemes treated so far, the acid waste water of the furfural process was directly submitted to a separation so as to obtain the carboxylic acids as a byproduct, for sale. It is, however, instructive to realize that apart from the small percentage of... 

By 1936, 40 plants of this general type were in operation, treating more than 180,000 bbl./day of kerosene (33). Diesel fuels may also be treated by this process to remove aromatic compounds which impair the ignition qualities of the fuel. A description of a recent installation is given by Dickey (34), and a thorough study of applications and a very complete bibliography is given by Defize (33). Furfural may also be used for this purpose (94). 

By 1949, over 20 installations of this process were treating approximately 60,000 bbl./day of feedstock. A recent installation, the largest of its kind, includes deaeration of the feed and vacuum -irippitig of the rafiinate and extract products, with flue-gas blanketing of the solvent storage tanks to minimize deterioration of the furfural (101). 

Figure 8.12 Furfural/acetic acid extraction plant to treat the condensate from Lenzing s sulfite pulping process (extraction efficiency -80-90%). ...

Byproduct flexibility Byproduct credits do not significantly affect the process economics. The furfural by-product produced from hemicellulose can be easily converted to levulinic acid (via hydrogenation to furfuryl alcohol) thereby significantly increasing the yield of the main product. Formic acid can be sold, converted to derivatives or waste-treated by gasification or anaerobic digestion to recover its energy value. 

Furfural Process. The use of furfural for lubricating-oil manufacture has been gaining in comparison with most other solvents. The yield of high Viscosity Index raffinate varies with the stocks being treated but is about 70 per cent for intermediate-base stocks and 95 per cent for par-... 

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