Steaming pretreatment, effect products

Peeling, one of the most delicate pretreatments, is achieved industrially by abrasion, high-pressure steam, treatment with sodium hydroxide solution, or mechanically. Abrasion is effected by rough, moving surfaces which remove the outer surface of the product, but it has the drawback of considerable loss of raw material. Steam peeling consists of heating the product to... 

The main feature in physical refining of crude oils is the application of steam distillation to remove the free fatty acids and volatile components from the oil. The technical feasibility of physical refining depends largely on the pretreatment stages for the removal of phosphatides, color bodies, metal ions, and nonvolatile impurities. Without an effective pretreatment, steam refining may fail to produce an oil of color and stability characteristics comparable to the classically refined product (23). 

Minowa et al. [17] at the National Institute for Resources and Environment, Japan, proposed treatment of city garbage at ten cratures lower than 200 C to "liquidize the garbage. This operation is different from conventional liquidization because the product material is not oil but a biomass slurry that can be obtained at much lower temperature. Specifically, they were able to liquidize a mixture of cabbage, steamed rice, clam shells, dried sardines, and butter en loyed as a garbage model by treating it in an autoclave. The product was a slurry, and solid conqronents were found to precipitate with time. However, when they operated at 150 C for 1 hour, the solid components could be suspended for more than several hours. They proposed that this process could be applied as an effective pretreatment for supercritical water gasification,... 

The effect of surfaces on the gaseous and solid products of the steam cracking of propane has been studied. The chemical nature of the surface near the reactor inlet has a significant effect on the reaction products while the surface near the exit does not. The material of the reactor tube appears to catalyze gas phase reactions as well as coke formation and gasification. Pretreatment of the reactor tube alters the chemical nature of the surface and, as a result, alters the effect of the material on the reaction products. 

Enzyme activity loss because of non-productive adsorption on lignin surface was identified as one of the important factors to decrease enzyme effectiveness, and the effect of surfactants and non-catalytic protein on the enzymatic hydrolysis has been extensively studied to increase the enzymatic hydrolysis of cellulose into fermentable sugars [7, 9 19]. The reported study showed that the non-ionic surfactant poly(oxyethylene)2o-sorbitan-monooleate (Tween 80) enhanced the enzymatic hydrolysis rate and extent of newspaper cellulose by 33 and 14%, respectively [20]. It was also found that 30% more FPU cellulase activity remained in solution, and about three times more recoverable FPU activity could be recycled with the presence of Tween 80. Tween 80 enhanced enzymatic hydrolysis yields for steam-exploded poplar wood by 20% in the simultaneous saccharification and fermentation (SSF) process [21]. Helle et al. [22] reported that hydrolysis yield increased by as much as a factor of 7, whereas enzyme adsorption on cellulose decreased because of the addition of Tween 80. With the presence of poly(oxyethylene)2o-sorbitan-monolaurate (Tween 20) and Tween 80, the conversions of cellulose and xylan in lime-pretreated com stover were increased by 42 and 40%, respectively [23]. Wu and Ju [24] showed that the addition of Tween 20 or Tween 80 to waste newsprint could increase cellulose conversion by about 50% with the saving of cellulase loading of 80%. With the addition of non-ionic, anionic, and cationic surfactants to the hydrolysis of cellulose (Avicel, tissue paper, and reclaimed paper), Ooshima et al. [25] subsequently found that Tween 20 was the most effective for the enhancement of cellulose conversion, and anionic surfactants did not have any effect on cellulose hydrolysis. With the addition of Tween 20 in the SSF process for... 

Cantarella et al. (2004) determined the effects of several ehemicals in the three main classes of toxins mentioned above, on subsequent enzymatic hydrolysis and simultaneous saccharifieation and fermentation (SSF) for the production of ethanol by Saccharomyces cerevisiae. Vanillin (0.5 g/1) was found to be the most potent inhibitor in SSF when compared to similar concentrations of 5-HMF and acetic acid. Longer lag phases and the most pronounced reduction in fermentation productivity were found when higher concentrations of acetic acid (i.e. 2 g/1) were used, while levulinic and formic acids at 1 g/1 were found to reduce ethanol production by 38% and 48%, respectively. Efficient and selective removal or substantial dilution of vanillin and the organic acid inhibitors found in steam-exploded hydrolysates were concluded to be the most important pretreatment considerations for improving process productivity. 

---