In the terms of technological economics, the more by-products are, the higher cost is apportioned, leading to low cost of the main product. That is to say, multiple products are an effective way to improve economic rationality.

The economic comparison between fractionation refining technology with multi­ple products and single technology with one product is presented in Table 4.1.

It demonstrates that if only the hydrolyzed carbohydrate of corn stalk is converted into acetone, butanol, and ethanol, products lack market competitiveness. What is worse, waste disposal would increase cost. On the contrary, if the whole stalk is frac­tionally converted into products, each product is market competitive. Moreover, there are no wastes left, which fulfills green industry requirement and realizes resource total utilization.

Compared with single pretreatment technology, the features of integrated pretreatment technology for stalk are as follows.

1. Integrated pretreatment is multiple products oriented, making best of each com­ponent for different products. Therefore, by-products increase the economic value of stalk and reduce discharge.

2. Integrated pretreatment is set up according to the heterogeneity of stalk in different levels, such as tissue level, cell level, and component level.

3. Integrated pretreatment is of wide adaptability because there are more adjustable parameters. Therefore, integrated pretreatment is also flexible and fit for various raw materials from different regions and planting manners.

4. For integrated technology, any idea and technology could be integrated includ­ing those from paper making, pinning and sheet industry, especially petroleum refining which is rational, economic, effective, clear, and operable.

5. Each technology involved in integrated pretreatment could be complement in advantages to reduce the whole pretreatment cost.

4.5 Conclusion

Stalk heterogeneous property in the level of tissue, cell, and component is ana­lyzed in terms of stalk morphology and anatomy. It is proved that different tissues, cells, and components have different conversion properties because of heterogeneous characteristics. Steam explosion integrated fractional refining technology is set up according to stalk heterogeneous intrinsic characteristics. The whole stalk is frac­tionated in the level of tissue, cell, and component and then converted into different products, respectively. Industrial demonstration proves that steam explosion inte­grated fractional refining technology is an effective way to improve the economic benefit of stalk utilization.

Acknowledgments Financial support to this study is provided by the National Basic Research Program of China (973 Project, No. 2011CB707401), the National High Technology Research and Development Program of China (863 Program, SS2012AA022502), the National Key Project of Scientific and Technical Supporting Program of China (No. 2011BAD22B02).