Bleaching Miscanthus x giganteus Acetosolv pulps with hydrogen peroxide/acetic acid. Part 1: Behaviour in aqueous alkaline media
ABSTRACT Miscanthus x giganteus bark samples subjected to fractionation by the Acetosolv process under optimal conditions were bleached using hydrogen peroxide and acetic acid in aqueous media under alkaline conditions. The inﬂuence of the main operational variables in the bleaching of Acetosolv pulps of M. x giganteus (i.e. hydrogen peroxide concentration, 3–7%; temperature, 55–75 ºC; pH 9–11), obtained after treatments, have been assessed on pulp yield, kappa number, viscosity and brightness of bleached pulps. For this purpose, a rotatable and orthogonal second-order factorial design of experiments was used, in order to identify the optimum operating conditions. The obtained empirical mathematical models demonstrate that, in general, the bleaching was efﬁcient, achieving pulps with kappa numbers below 10. The chemical composition and physicochemical properties of the bleached pulps fulﬁlled the requirements for forthcoming bleaching stages. Moreover, an alkaline extraction stage to eliminate saponiﬁable groups of Acetosolv pulps was studied, as well as the necessity of use chelating agents in the stage with hydrogen peroxide.
- SourceAvailable from: Qi-Ning Sun[Show abstract] [Hide abstract]
ABSTRACT: Miscanthus represents a key candidate energy crop for use in biomass-to-liquid fuel-conversion processes and biorefineries to produce a range of liquid fuels and chemicals; it has recently attracted considerable attention. Its yield, elemental composition, carbohydrate and lignin content and composition are of high importance to be reviewed for future biofuel production and development. Starting from Miscanthus, various pre-treatment technologies have recently been developed in the literature to break down the lignin structure, disrupt the crystalline structure of cellulose, and enhance its enzyme digestibility. These technologies included chemical, physicochemical, and biological pre-treatments. Due to its significantly lower concentrations of moisture and ash, Miscanthus also represents a key candidate crop for use in biomass-to-liquid conversion processes to produce a range of liquid fuels and chemicals by thermochemical conversion. The goal of this paper is to review the current status of the technology for biofuel production from this crop within a biorefinery context.Biofuels Bioproducts and Biorefining 07/2012; 6(5):580-598. · 3.77 Impact Factor
Conference Paper: Fractionally spaced equalizers with adaptive sampling[Show abstract] [Hide abstract]
ABSTRACT: A new structure of fractionally spaced equalizer (FSE) is described. A conventional FSE has taps spaced equally T/M, where T is the symbol spacing and M is an integer. Although there are many advantages of FSE in digital data transmission, the computational requirements increase with factor M. We describe a non-equally spaced FSE (NFSE) with less computational requirements. A novel tap control algorithm for NFSE under some restrictions is also presentedAcoustics, Speech, and Signal Processing, 1994. ICASSP-94., 1994 IEEE International Conference on; 05/1994