Conceptual process engineering builds a bridge from science and researchers to plant engineers, investment project teams and production personnel.
Author: Panu Tikka
Comments on conceptual engineering – Introduction
by Heikki Hassi & Panu Tikka Since the beginning in 1983, key service offerings of SciTech-Service Oy Ltd have covered the range from scientific research and development to plant engineering, focusing on biomass-based technologies and processes. In other words, our aim is to bridge the gap between R&D and industrial process technology – two fields, which are mastered by quite …
Transport phenomena in kraft (sulphate) cooking process
Wood substance is a very complicated porous structure consisting of lignin bound wood fibers. We were initializing and leading a 15 years period of research on these issues and their interdependence s with pulp industry, machinery manufacturers and Helsinki University of Technology.
Chemical and Physical performance of Kraft Pulp Cooking
Kraft pulp mill process has become the only dominating cooking process for making chemical pulp. In the 1980’s started an active period where a lot of old conventional cooking capacity were replaced by new mills.
Soap and turpentine in softwood kraft mills
Panu Tikka wrote a short commentary on one of his old publications: PaT 180721 Tikka, et al.Solving soap and turpentine related process problems in softwood kraft mills.P&P Can, 103(2002)6:T 149, p 30 – 35 In the modern more and more sustainable biobased economy the old obnoxious word “pulp mill” is being replaced by a better expression “ bioproduct plant “ …
Re-visiting another 90’s breakthrough invention
Panu Tikka re-visits another SciTech-Service 90’s patent: “Process for the production of a hemicellulose hydrolysate and special high alpha cellulose pulp”
Re-visiting the patent Process for preparing kraft pulp
Panu Tikka re-visited his patent issued back in 2002 entitled “Process for preparing kraft pulp”. Panu shortly describes his invention and how it affected current pulp mills processes.
Determination of the contribution of penetration, diffusion and alkali consumption in the impregnation of Eucalyptus grandis chips.
ABSTRACT The influence of impregnation conditions on the phenomena involved in the impregnation of Eucalyptus grandis chips was studied with the aid of a new impregnation method. When pre-steaming was used, 30 minutes of penetration time was sufficient to achieve the final degree of penetration (over 95%) with white and black liquor. An impregnation time of 15 minutes was found …
Determination of phenomena involved in impregnation of softwood chips. Part 1. Method for calculating the true penetration degree.
ABSTRACT In earlier studies the degree of penetration was calculated with a method which gave a penetration degree of over 100%, if mill liquors were used, because the method ignored the diffusion of cooking chemicals and dissolution of wood material. In this paper, a new experimental research method is presented, which allows the penetration of mill liquors to be examined …
Determination of phenomena involved in impregnation of softwood chips. Part 2: alkali uptake, alkali consumption and impregnation yield.
ABSTRACT The influence of impregnation conditions on the phenomena involved in impregnation was studied with the aid of a new impregnation method. The method was found to be good enough for scientific research purposes and useful for gaining new knowledge of the alkali uptake, alkali consumption and dissolution of wood material during impregnation. An impregnation time of slightly over 15 …
Towards complete impregnation of wood chips with aqueous solutions. Part I. A retrospective and critical evaluation of the penetration process.
ABSTRACT This paper evaluates the process of liquid penetration into wood chips from the retrospective viewpoint of industrial development and research and provides a summary of currently available knowledge in this area. During the past few decades, researchers have been dealing mainly with pulping chemistry and the back-end of pulping processes, while less attention has been paid to the front-end …
Specific Permeability of Wood to Water. Part 1: Longitudinal Specific Permeability of Steamed, Impregnated, and Kraft-Cooked Wood.
ABSTRACT Two apparatuses for measuring the specific permeability of wood specimens are presented. The developed method was used to measure specific permeability to water in the longitudinal direction (of the log) for three wood species, pine (Pinus sylvestris), birch (Betula pendula), and eucalyptus (Eucalyptus grandis). The wood species were cooked to a certain degree under kraft cooking conditions. The effect …
Specific Permeability of Wood to Water. Part 2: Perpendicular Specific Permeability of Steamed, Impregnated, and Kraft-Cooked Wood.
ABSTRACT A method for measuring the perpendicular specific permeability of wood specimens to water is presented, which is a modification of the method presented in part 1 of this work. The specific permeability in the perpendicular direction of the log of three wood species, pine (Pinus sylvestris), birch (Betula pendula), and eucalyptus (Eucalyptus grandis), was measured from kraft-cooked wood of …
Penetration of water into industrial softwood chips – influence of physical properties.
ABSTRACT In earlier studies, the fundamentals of the liquor penetration process in the case of hand made, homogenous, identically shaped wooden blocks have been studied. However, the efficiency of liquor penetration into real industrial chips may differ from the efficiency of penetration into ideal handmade chips. In this paper, impregnation experiments with three industrial softwood chip grades including sawmill chips, …
Penetration of water and black liquor into overthick and treated wood chips.
ABSTRACT In this paper, the penetration of water and black liquor into overthick and pre-treated overthick chips (cracked and re-chipped according to thickness) was studied with a laboratory impregnator to investigate ways to improve penetration. Overthick chips were divided in three categories: knot-containing chips, chips without knots and original overthick chips. The results of the penetration experiments were evaluated in …
Solving soap and turpentine related process problems in softwood draft mills
Abstract Effective separation of soap and turpentine is an important, but mill-specific aspect, regarding the entire softwood kraft process performance. This paper describes a systematic approach to evaluate and solve various extractives-related process problems. In a mill “audit”, the soap and extractives potential of the mill’s wood raw material is first estimated, the key process streams are tested and the …
Towards complete impregnation of wood chips with aqueous solutions. Part 5: improving uniformity of kraft displacement batch pulping.
ABSTRACT Pulping uniformity is critical for improving the performances of cooking and downstream operations such as bleaching and papermaking. In spite of certain success of recent modifications of batch and continuous kraft cooking systems, there is still a lot of room for improving the contemporary cooking systems in order to address problem of heterogeneous pulping. Incomplete penetration and inadequate diffusion …
Towards complete impregnation of wood chips – new research enables effective processes.
ABSTRACT The important role of impregnation prior to chemical pulping has been long recognized qualitatively but not fully realized quantitatively. Cost effective production of uniform, high quality pulp can only be achieved by efficient mass transfer of pulping chemicals that must start with complete impregnation of wood chips. The present paper describes the main results of an in-depth research project …
The washing efficiency of digester displacement: new aspects based on laboratory studies and improved calculation procedures.
ABSTRACT Displacement batch cooking is nowadays a common practice in the production of kraft pulp. The cook is terminated by a cool filtrate displacement, in which the temperature of the digester is brought down. The terminal displacement is the first washing stage in the pulp mill. The displacement operation is widely practiced, but knowledge of the washing effect of the …
Towards complete impregnation of wood chips with aqueous solutions. Part 4. Effects of front-end modifications in displacement batch kraft pulping.
ABSTRACT The front-end of kraft cooking, i.e. steaming, impregnation and heating, controls the cooking performance in terms of mass transfer, delignification and cooking uniformity. Therefore, it is of vital importance to understand the process mechanisms and optimise the front-end process conditions. This article discusses the effect of applying chip presteaming and higher pressure at the front-end of kraft displacement batch …
Efficiency of chip presteaming – result of heating and air escape processes.
SUMMARY Efficient removal of air from the wood chips prior to impregnation with cooking liquor is important for achieving pulping uniformity and improving the overall digester performance. Because of its effectiveness, relative simplicity and other advantages, steaming of wood chips became a primary process in pulp industry to fulfil this task. In the present article the process of chip presteaming …
Towards complete impregnation of wood chips with aqueous solutions. Part 2. Studies on water penetration into softwood chips.
ABSTRACT Importance of the chip impregnation stage is widely recognised in chemical pulping processes. However, there is limited amount of direct data on mass transfer during the impregnation stage. Most methods used for studying the liquid penetration process were based on indirect approaches. A new laboratory impregnator with a special weight sensor was developed, which allowed the direct measurements of …
Towards complete impregnation of wood chips with aqueous solutions. Part 3. Black liquor penetration into pine chips.
ABSTRACT Presteaming of chip and applied pressure greatly influence penetration of black liquor into pine chips. Complete penetration of sapwood chips can be reached just by applying extra pressure. To achieve a high degree of penetration of the heartwood chips, air present within the wood capillaries has to be removed by presteaming. Efficient liquor penetration achieved by optimising conditions at …
Softwood fiber damage – a newly discovered enigma in modern kraft fiber lines.
ABSTRACT Studies of pulp strength delivery have shown that cooking is the most significant step causing strength losses in softwood pulp. In the early 1990s it was demonstrated that different cooking processes resulted in different strength delivery and that displacement kraft batch cooking systems resulted in a pulp strength which comes very close to the strength of the laboratory reference …
Studies on industrial digesters and cooking performance – Methods and applications (Helsinki University of Technology)
ABSTRACT Industrial pulp cooking reactors, digesters, were introduced in the early stages of chemical pulping technology for chemical liberation of fibres from wood chips and other lignocellulosic materials. With cooking temperatures of 20 – 80 °C above the boiling point of water and strong chemicals such as sodium hydroxide, suiphide or suiphite, digesters had to be sturdy and big. When …
Behavior of pine wood material during displacement kraft batch cooking.
ABSTRACT Pine wood (Pinus sylvestris) was delignified using a modern displacement kraft cooking method. A series of laboratory-scale cooks (stop-cooks) was carried out to different cooking degrees representing i) the end points of warm black liquor impregnation (temperature 80°C, total yield 93.3%) and hot black liquor pretreatment (temperature 155°C, total yield 77.5%) and ii) varying chlorine numbers (1.8-7.0) in the …
Effects of softwood morphology and chip thickness on pulping with a displacement kraft batch process.
ABSTRACT This study examines the effect of softwood raw-material properties on pulp quality. Logs of Scots pine (Pinus sylvestris), Norway spruce (Picea abies), and loblolly pine (Pinus taeda) were the raw materials. Wood from Scots pine and Norway spruce was further classified by age as (a) pulpwood (mature wood and older thinnings) or (b) young wood (first thinnings and top …
Pulping and paper technical characteristics of the Sumatra tropical hardwoods.
Pulping and paper technical characteristics of the Sumatra tropical hardwoods. 52nd Appita Annual General Conference, Brisbane, Australia
Relations between cooking conditions, pulp quality and bleachability as studied using a new superbatch experimental cooking system.
ABSTRACT Cooking, oxygen delignification, and ECF bleaching characteristics of Scandinavian pine were studied using a recently implemented lab. scale displacement cooking system. Cooking with white liquor was varied over a wide range in order to produce pulps of varying delignification degrees and yields with const. impregnation and hot black liquor treatment. The pulps were then oxygen delignified and bleached with a D(EOP)DD sequence, again varying conditions in order to evaluate delignification and brightness …
Chip thickness vs. kraft pulping performance: experiments by multiple hanging baskets in batch digesters.
ABSTRACT Differently screened chip samples were placed in baskets and were cooked inside industrial batch digesters. These basket pulps were analyzed with regard to yield, delignification degree, rejects, and pulp strength. Thickness screening was shown to be advantageous to conventional batch cooking and to full displacement cooking. In both methods, the rejects could be cut in half by using thickness– screened chips. Moreover, the SuperBatch cooking process, a modified full …
Present prospects of the neutral sulfite-anthraquinone method
ABSTRACT The title process was briefly reviewed and results for pulp prodn. with northern and middle European timber were discussed for a chlorine-free bleaching technique in a closed system.