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Metai A.,ITT Wedeco | Germer E.,Saint Petersburg State Forest Technical Academy | Hostachy J.-C.,ITT Wedeco
International Pulp Bleaching Conference 2011, IPBC 2011 | Year: 2011

The first industrial production of ozone bleached pulp started almost 20 years ago in connection with increasing environmental pressure and the Total Chlorine Free (TCF) wave. Like many other new technologies, ozone bleaching did not immediately reach its optimal efficiency from a technical viewpoint, but had to face several issues during its early years. By improving mixing technology, better understanding ozone chemistry on pulp components and tuning the whole process, the so-called ECF-Light bleaching sequences - including an ozone stage - made it possible to deliver a pulp quality similar or better than conventional ECF bleaching would do. Today the choice of ozone may still be motivated by ecological requirements but it is mostly justified by the economical savings resulting from chemicals costs cut-off. Actually, both targets are reached simultaneously when implementing an ozone bleaching stage. Through several industrial results, this work describes process improvements in ozone bleaching since 1992 and points out why should ozone now be considered as a keystone of modem pulp bleaching processes.


Germer E.,Saint Petersburg State Forest Technical Academy | Metais A.,ITT Wedeco | Hostachy J.-C.,ITT Wedeco
PPI Pulp and Paper International | Year: 2011

Some of the significant benefits of industrial ozone bleaching in pulp mills are discussed. Ozone bleaching is efficiently used on hardwood and softwood pulps, on kraft, and sulphite pulps dedicated to all kinds of final applications. Investors always focus on the return on investment (ROI) and all TCF ozone users have realized that bleaching costs are reduced by 20-32% when introducing an ozone stage in an ECF bleaching line, including in the case of TCF bleaching. The high bleaching efficiency of ozone also allows a significant reduction in the consumption of expensive bleaching chemicals. These chemicals include chlorine dioxide in ECF bleaching and hydrogen peroxide in TCF bleaching, along with sodium hydroxide in ECF bleaching and TCF bleaching. Ozone users have also observed that bleaching with an ozone stage gives a wide range of opportunities without affecting the pulp strength properties in comparison with conventional ECF sequences.


Metais A.,ITT Wedeco | Germer E.,Saint Petersburg State Forest Technical Academy | Hostachy J.-C.,ITT Wedeco
Paper Technology | Year: 2011

First industrial production of ozone bleached pulp started almost 20 years ago in connection with increasing environmental pressure and the Total Chlorine Free (TCF) wave. Like many other new technologies, ozone bleaching did not immediately reach its optimal efficiency from a technical viewpoint, but had to face several issues during its early years. By improving mixing technology, better understanding ozone chemistry on pulp components and tuning the whole process, the socalled ECF-Light bleaching sequences - including an ozone stage - made it possible to deliver a pulp quality similar or better than is produced by conventional ECF bleaching. Today the choice of ozone may still be motivated by ecological requirements but it is mostly justified by the economical savings resulting from chemical reduction. Actually, both targets are reached simultaneously when implementing an ozone bleaching stage, whilst pulp quality is either maintained or improved. Using results from several industrial sites, this article describes process improvements in ozone bleaching since 1992 and shows why ozone should now be considered as the keystone of modern pulp bleaching processes.


Utkin L.V.,Saint Petersburg State Forest Technical Academy | Zatenko S.I.,Saint Petersburg State Forest Technical Academy | Coolen F.P.A.,Durham University
Automation and Remote Control | Year: 2010

We propose a new class of models for software reliability based on known models employing non-homogeneous Poisson processes, e.g., Musa-Okomoto and Goel-Okomoto models. We show that the general idea of model design is in a combined application of imprecise Bayesian inference and the maximum likelihood approach. We show examples where proposed models show better reliability prediction quality compared to the known ones. © Pleiades Publishing, Ltd., 2010.


Stepakov A.V.,Saint Petersburg State University | Popova E.A.,Saint Petersburg State University | Stepakova L.V.,Saint Petersburg State University | Boitsov V.M.,Saint Petersburg State University | And 2 more authors.
Tetrahedron | Year: 2010

Imides of arylmaleic acids in the presence of 3,5-dimethyl-IH-pyrazole underwent (4+2) dimerization under heating in chlorobenzene within 24 h to afford 1,2,3,3a,3b,4,5,6,6a,10b-decahydrobenzoe1pyrrolo [3,4-g]isoindole-1,3,4, 6-tetraones in good yields. It was established that during the heating of imides of arylmaleic acid in 2,6-lutidine at 100 °C the (4+2) dimerization products containing a lutidine fragment are obtained. © 2010 Elsevier Ltd.


Krutov S.M.,Saint Petersburg State Forest Technical Academy | Sumerskiy I.V.,Saint Petersburg State Forest Technical Academy | Soultanov V.S.,Solagran Ltd | Gribkov I.V.,Saint Petersburg State Forest Technical Academy | Zarubin M.Y.,Saint Petersburg State Forest Technical Academy
16th International Symposium on Wood, Fiber and Pulping Chemistry - Proceedings, ISWFPC | Year: 2011

Composition of technical hydrolytic lignin, such as amount of Klason lignin, extractive substances, polysaccharides and ash content had been investigated. Hydrolytic lignin samples were obtained from seven bioethanol plants directly after production and from the waste area near the hydrolysis plants. Both chromatographic [gas chromatography-mass spectrometry (GC-MS), pyrolysis gas chromatography-mass spectrometry (Py-GC-MS)] and spectrometric [nuclear magnetic resonance ( 13C-NMR)] methods were used for analysis of lignin samples. Most efficient and perspective directions of hydrolytic lignin industrial application had been proposed.


Golovin A.V.,Saint Petersburg State Polytechnic University | Ponomarev D.A.,Saint Petersburg State Forest Technical Academy | Takhistov V.V.,Russian Academy of Sciences
Journal of Theoretical and Computational Chemistry | Year: 2010

Analysis of theoretical enthalpies of formation for about 300 molecules and their fragments (free radicals, biradicals, and ions) was performed to show that the results of semiempirical, DFT, and ab initio methods must be taken with great caution. A brief review of the authors' alternative empirical methodologies for calculation of enthalpies of formation for molecules (enthalpic shift procedure) and free radicals (enthalpies of isodesmic reactions) is given. © 2010 World Scientific Publishing Company.


Utkin L.V.,Saint Petersburg State Forest Technical Academy | Kozine I.,Technical University of Denmark
Structural Safety | Year: 2010

New imprecise structural reliability models are described in this paper. They are developed based on the imprecise Bayesian inference and are imprecise Dirichlet, imprecise negative binomial, gamma-exponential and normal models. The models are applied to computing cautious structural reliability measures when the number of events of interest or observations is very small. The main feature of the models is that prior ignorance is not modelled by a fixed single prior distribution, but by a class of priors which is defined by upper and lower probabilities that can converge as statistical data accumulate. Numerical examples illustrate some features of the proposed approach. © 2010 Elsevier Ltd.


Germer E.,Saint Petersburg State Forest Technical Academy | Metais A.,Xylem Inc. | Van Wyk B.,Xylem Inc. | Hostachy J.-C.,Xylem Inc.
Paper360 | Year: 2012

Mills in India, Russia, and China are about to upgrade to modern and environmentally acceptable bleaching technologies. From an economical standpoint, the use of an ozone bleaching stage is even more advantageous in the case of TCF bleaching, which until today has been the alternative to chlorinated chemicals and sulfite pulp bleaching. Traditional ECF bleaching has been used in the industry since the late 1980s without any essential modifications, which suggests that it has reached its limit in technical improvements. Ozone-enhanced Light-ECF should be chosen over traditional ECF for kraft pulp bleaching modernization and green field projects, while TCF should be chosen in the case of sulfite pulp bleaching. The ozone bleaching discussion at the mill had been closed for a long time, for the simple reason that the head office held a negative opinion that the mill technical manager had to accept.


Germer E.,Saint Petersburg State Forest Technical Academy | Metais A.,Xylem Inc. | Hostachy J.-C.,Xylem Inc.
International Paperworld IPW | Year: 2012

Some of the challenges that are faced in implementing new technology in paper mills are discussed. A large number of green-field projects or mills deciding to get rid of chlorine and hypochlorite have selected the outdated ECF bleaching in place of ozone-enhanced Light-ECF bleaching. One of the challenges in implementing new technology involves the availability of outdated in formation. Another challenge is that engineering companies contracted to implement a new technology in such a paper mill tend to use the tried and tested technology that has been found to be reliable and useful in other facilities. These engineering companies avoid recommending the implementation of a technology, which lacks earlier use in any facility or process. It is beneficial for the engineering company to lower its input, its expenses, and standardize its work to get the job done at a lower cost and in a shorter time.

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