Modelling of the drying section of a continuous paper machine : a thesis presented in partial fulfilment of the requirement for the degree of Master in Production Technology at Massey University

The invention of paper in 105 A.D. was a milestone in the history of civilization and demand for paper has been increasing steadily ever since. Although it has become more and more popular to store, process and transfer information in electronic forms, paper is to date still the most common means for recording information. According to Storat (1993), production in the last twenty years has increased by more than 60 percent, while capital expenditures in the industry have grown to almost 12 percent of sales, or double the average expenditures of other manufacturing industries. This capital investment has gone towards capacity expansion and extensive rebuilds of existing mills - almost 60 percent of the existing capacity comes from modern facilities containing machines either newly installed or rebuilt in the past ten years. As a result, fossil fuel and energy consumption in this industry fell by 46 percent in the last two decades.[FROM INTRODUCTION

Data Driven Surrogate Based Optimization in the Problem Solving Environment WBCSim

Large scale, multidisciplinary, engineering designs are always difficult due to the complexity and dimensionality of these problems. Direct coupling between the analysis codes and the optimization routines can be prohibitively time consuming due to the complexity of the underlying simulation codes. One way of tackling this problem is by constructing computationally cheap(er) approximations of the expensive simulations, that mimic the behavior of the simulation model as closely as possible. This paper presents a data driven, surrogate based optimization algorithm that uses a trust region based sequential approximate optimization (SAO) framework and a statistical sampling approach based on design of experiment (DOE) arrays. The algorithm is implemented using techniques from two packages—SURFPACK and SHEPPACK that provide a collection of approximation algorithms to build the surrogates and three different DOE techniques—full factorial (FF), Latin hypercube sampling (LHS), and central composite design (CCD)—are used to train the surrogates. The results are compared with the optimization results obtained by directly coupling an optimizer with the simulation code. The biggest concern in using the SAO framework based on statistical sampling is the generation of the required database. As the number of design variables grows, the computational cost of generating the required database grows rapidly. A data driven approach is proposed to tackle this situation, where the trick is to run the expensive simulation if and only if a nearby data point does not exist in the cumulatively growing database. Over time the database matures and is enriched as more and more optimizations are performed. Results show that the proposed methodology dramatically reduces the total number of calls to the expensive simulation runs during the optimization process

Modeling and simulation of drying operation in PVC powder production line: a pneumatic dryer model

A one-dimensional steady-state model is developed to simulate drying of PVC powder in a pneumatic dryer. In this model, a two-phase continuum model was used to describe the steady-state flow of a dilute dispersed phase (wet PVC powder) and a continuous phase (humid air) through dryer. The particle scale kinetics was obtained by immersion of a fixed mass of wet PVC’s particles (cake) in a batch dense fluidized bed containing inert hot particles (glass bead). The drying kinetics was described by a shrinking core type model and integrated in pneumatic dryer model. The results show that the inlet temperature is the most important parameter in the operation. The drying rate is controlled by a two-stage process. The first stage corresponds to the surface water evaporation, and the second to the pore water evaporation

Innovative and eco-sustainable processing and packaging for safe and high quality organic products with enhanced nutritional quality. Final report

The main goal of the project has been to develop innovative sustainable processing and packaging technologies to meet the growing consumer demand and boost the manufacturing of safe organic berry products with high nutritional quality and low environmental impact. The aim has been to evaluate technologies to naturally extend the shelf-life of fresh organic berries and to process berries into a wide variety of value added products. Several solutions and technologies for extending shelf life and the overall quality of fresh and processed berry and fruit products have been identified and developed during the three years of the project

Research of heat and mass transfer processes in conditions of microwave heating of wet wood

The results of experimental and theoretical studies of the processes of heat and mass transfer occurring during drying of wood under microwave heating are presented. The times of moisture removal are set. It is established that the dynamics of dehydration depends on the type of wood. Based on the results of experimental studies, a mathematical model of the heat transfer processes taking place under conditions of intensive phase transformations (evaporation of water) is formulated together during the dehydration of the wood. A comparative analysis of the theoretical and experimental values of the drying times showed their satisfactory consistency

Effect of curing conditions and harvesting stage of maturity on Ethiopian onion bulb drying properties

The study was conducted to investigate the impact of curing conditions and harvesting stageson the drying quality of onion bulbs. The onion bulbs (Bombay Red cultivar) were harvested at three harvesting stages (early, optimum, and late maturity) and cured at three different temperatures (30, 40 and 50 oC) and relative humidity (30, 50 and 70%). The results revealed that curing temperature, RH, and maturity stage had significant effects on all measuredattributesexcept total soluble solids

Modification of the CAB Model for Air-Assist Atomization of Food Sprays

The Cascade Atomization and Drop Breakup (CAB) model has been originally developed for pressure atomizers. In this study, the CAB model is modified to accommodate the atomization of low-pressure, air-assist atomizers. The modifications include the first breakup which is modeled by estimating theWeber number due to the increased liquid-gas relative velocity caused by the air flow. This breakup depends on whether the Weber number is in the catastrophic, stripping or bag breakup regime. The second modification includes a change in the product drop distributions, namely, instead of a uniform distribution, as used in the original CAB model, a X-squared distribution with the same average drop size is assumed. The model changes are validated with experimental data obtained by means of two different air-assist atomizers using an oil-in-water emulsion. The simulations are performed with a modified version of the KIVA-3 CFD code; they show good agreement with the experiments

Technologies of Physical Monitoring and Mathematical Modeling for Estimation of Ground Forest Fuel Fire Condition

Description of new experimental installations for the control of parameters of environment with a view of monitoring of forest fires presented in article. Stationary and mobile variants developed. Typical results of operation of installations during a fire-dangerous season of 2015 in vicinities of Ulan-Ude (Republic Buryatiya, Russia) presented. One-dimensional mathematical model of forest fuel drying which can be used for monitoring of forest fire danger with attraction of environmental parameters data during fire-dangerous season offered. Verification of mathematical model with use of known experimental data spent

Development of a new software application for supporting research of thermo-mechanical behavior of agri-food and forest products

Development of applications and services conforming to recent standards and perspectives of ICT is important for increasing productivity in agri-food and forestry sectors to deliver desired quantities of safe and quality products to end-users. Therefore a field of study combining two national curricula: informatics and agricultural engineering was developed by the Department of Applied Informatics of the Poznan University of Life Sciences. The scope of studies corresponds to the area of research conducted in the Department and focuses on development of Web-based advisory systems for agriculture and information systems supporting research in the agri-bio-engineering. In the paper two exemplary systems are presented. They support analysis of thermo-mechanical behavior of agri-food and forest products subjected to heating, cooling, drying and storing operations. Development of the systems resulted in a significant increase in accuracy and efficiency of estimating properties of biomaterials and in more accurate predictions of the processes investigated.</jats:p