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Development and testing of a novel lab-scale direct steam-injection apparatus to hydrolyse model and saline crop slurries
- Source :
- Journal of Biotechnology. 157:590-597
- Publication Year :
- 2012
- Publisher :
- Elsevier BV, 2012.
-
Abstract
- In this work, a novel laboratory-scale direct steam-injection apparatus (DSIA) was developed to overcome the main drawback of the conventional batch-driven lab rigs, namely the long time needed to heat fiber slurry from room to reaction temperatures greater than 150 °C. The novel apparatus mainly consisted of three units: (i) a mechanically-stirred bioreactor where saturated steam at 5-30 bar can be injected; (ii) an automatic on-off valve to flash suddenly the reaction medium after a prefixed reaction time; (iii) a cyclone separator to recover the reacted slurry. This system was tested using 0.75 dm³ of an aqueous solution of H₂SO₄ (0.5%, v/v) enriched with 50 kg m⁻³ of either commercial particles of Avicel® and Larch xylan or 0.5 mm sieved particles of Tamarix jordanis. Each slurry was heated to about 200 °C by injecting steam at 28 bar for 90 s. The process efficiency was assessed by comparing the dissolution degree of suspended solid (Y(S)), as well as xylose (Y(X)), glucose (Y(G)), and furfural (Y(F)) yields, with those obtained in a conventional steam autoclave at 130 °C for 30 or 60 min. Treatment of T. jordanis particles in DSIA resulted in Y(S) and Y(G) values quite similar to those obtained in the steam autoclave at 130 °C for 60 min, but in a less efficient hemicellulose solubilization. A limited occurrence of pentose degradation products was observed in both equipments, suggesting that hydrolysis predominated over degradation reactions. The susceptibility of the residual solid fractions from DSIA treatment to a conventional 120 h long cellulolytic treatment using an enzyme loading of 5.4 FPU g⁻¹ was markedly higher than that of samples hydrolysed in the steam autoclave, their corresponding glucose yields being equal to 0.94 and 0.22 g per gram of initial cellulose, respectively. Thus, T. jordanis resulted to be a valuable source of sugars for bioethanol production as proved by preliminary tests in the novel lab rig developed here.
- Subjects :
- Crops, Agricultural
Salinity
Time Factors
Steam injection
Bioengineering
Furfural
Models, Biological
Applied Microbiology and Biotechnology
Autoclave
chemistry.chemical_compound
Hemicellulose
Cellulose
Steam explosion
Xylose
Sewage
Tamaricaceae
Chemistry
business.industry
Hydrolysis
Superheated steam
General Medicine
Biotechnology
Steam
Glucose
Slurry
Laboratories
business
Nuclear chemistry
Subjects
Details
- ISSN :
- 01681656
- Volume :
- 157
- Database :
- OpenAIRE
- Journal :
- Journal of Biotechnology
- Accession number :
- edsair.doi.dedup.....f50709ed8005967f7859e86c7b452050