Continuous Steam Explosion Research Articles

Non-isothermal crystallization kinetics and dynamic mechanical thermal properties of poly(butylene succinate) composites reinforced with cotton stalk bast fibers

Degradable poly(butylene succinate) (PBS) was reinforced with cotton stalk bast fibers (CSBF) which had been pre-treated by the continuous steam explosion method. The non-isothermal crystallization kinetics, crystalline structure and spherulitic morphology of neat PBS and CSBF/PBS composites were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and polarizing optical microscopy (POM). Moreover, the dynamic mechanical thermal properties of neat PBS and CSBF/PBS composites were studied by dynamic mechanical thermal analysis (DMA). The results showed that CSBF played a dual role for acting as both nucleating agents to promote nucleation and physical hindrances to retard the transport of chain segments during the non-isothermal crystallization. In non-isothermal crystallization kinetics, the Ozawa model failed to describe the crystallization behavior of these systems, while Avrami model and Liu model (modified Avrami–Ozawa model) were found applicable. Though the spherulites drastically decreased in size when CSBF were added into PBS matrix, the crystalline structure did not change. In addition, the presence of CSBF largely enhanced the storage modulus of PBS matrix.

Rheological analysis of corn straw pretreated by screw extrusion and continuous steam explosion

Rheological analysis of corn straw pretreated by screw extrusion and continuous steam explosion

Dilute Acid Pretreatment of Black Spruce Using Continuous Steam Explosion System

The pretreatment of lignocellulosic materials prior to the enzymatic hydrolysis is essential to the sugar yield and bioethanol production. Dilute acid hydrolysis of black spruce softwood chip was performed in a continuous high temperature reactor followed with steam explosion and mechanical refining. The acid-soaked wood chips were pretreated under different feeding rates (60 and 92kg/h), cooking screw rotation speeds (7.2 and 14.4rpm), and steam pressures (12 and 15bar). The enzymatic hydrolysis was carried out on the acid-insoluble fraction of pretreated material. At lower feeding rate, the pretreatment at low steam pressure and short retention time favored the recovery of hemicellulose. The pretreatment at high steam pressure and longer retention time recovered less hemicellulose but improved the enzymatic accessibility. As a result, the overall sugar yields became similar no matter what levels of the retention time or steam pressure. Comparing with lower feeding rate, higher feeding rate resulted in consistently higher glucose yield in both liquid fraction after pretreatment and that released after enzymatic hydrolysis.

Technoeconomic study on steam explosion application in biomass processing.

This work is based on the data collected during trials of a continuous steam explosion (SE) plant, with a treatment capacity of about 350 kg/h, including the biomass fractionation section. The energy and water consumption, equipment cost, and manpower needed to run this plant have been used as the base case for a techno-economic evaluation of productive plants. Three processing plant configurations have been considered: (I) SE pretreatment only; (II) SE followed by the hemicellulose extraction; (III) SE followed by the sequential hemicellulose and lignin extractions. The biomass treatment cost has been evaluated as a function of the plant scale. For each configuration, variable and fixed cost breakdown has been detailed in the case of a 50,000 t/y plant.

The Italian steam explosion program at ENEA

The Italian National Agency for New Technology, Energy and Environment (ENEA) conducts research, development and testing on innovative technologies and equipment and on technology transfer to industry and agriculture. The Agency has a staff of around 5000 Italy-wide. In 1987, ENEA began a research project on new processes and technologies concerning the conversion of ligno-cellulosic materials. In 1992, a continuous steam explosion pilot plant designed by Stake Technology Ltd., Ontario, Canada was installed at the ENEA Trisaia Centre in Southern Italy. This has a capacity of 175 Kg h −1 throughput of dry biomass. The plant is also equipped with two continuous extraction systems for the separation of hemicellulose, lignin and cellulose. This work presents the main characteristics of the continuous pilot plant, the strategies and/or products; finally, introduces new applications of the steam explosion process which ENEA is carrying out in collaboration with an Italian Firm, SADEPAN CHIMICA Spa, to produce fibreboards or chemicals from agro-industrial residues.