Krzysztof Urbaniec

Minimum energy consumption in sugar production by cooling crystallisation of concentrated raw juice

Abstract The sugar manufacturing process based on cooling crystallisation of concentrated raw juice is considered. Micro-filtration and softening of raw juice makes it possible to obtain white sugar by three-or four-stage cooling crystallisation. Prior to crystallisation, raw juice should be concentrated by multistage evaporation in a pressure range below the atmospheric pressure. The preferred evaporator arrangement is backward feed. As the temperature of vapours and condensates leaving the evaporator station is low, the opportunities for heat recovery are limited. In order to save energy, vapour recompression can be applied. For a given evaporator structure, the energy consumption depends on the parameters of the evaporation process. The minimum energy consumption of the novel process should thus be determined by simultaneously carrying out energy targeting and optimisation of evaporation. It is assumed that the consumption of utilities in the sugar factory is balanced with the supply of heat and power from the factory’s own power plant. Energy systems employing various CHP technologies and various evaporator stations optionally combined with vapour compressors are studied. A range of feasible solutions is defined in terms of minimum energy consumption and combined heat transfer area of the evaporator station and the heat exchanger network.

The evolution of evaporator stations in the beet-sugar industry

The main structural features of a multistage evaporator station are identified and their dependence on the requirements relating to the beet-sugar process is discussed. Developments in the scheme of multistage evaporation and preferred evaporator design over the recent decades are reviewed. Approaches making it possible to optimise the multistage evaporator station are mentioned and two examples of advanced stations implemented in beet-sugar factories by retrofitting outdated evaporation equipment are presented. It is stressed that the optimum retrofit results can be achieved by simultaneously reconstructing the evaporator station and the associated heat exchanger network.

Integration study on a two-stage fermentation process for the production of biohydrogen

In order to make the hydrogen economy fully sustainable, renewable resources have to be employed for its production. Simulation models, developed with Aspen Plus to calculate mass and energy balances, will be used to integrate the process steps necessary to produce pure hydrogen from biomass in a 2-stage fermentation process. The main challenge is the reduction of water and heat demand connected to the low substrate concentration in the fermentation steps; the easiest solution is to partly recirculate outgoing process streams. Electrolyte equilibrium was considered during simulation of different recirculation options to evaluate important effects on the pH and on the system osmolality. The results show that certain recirculation options can reduce the heat and water demand significantly. (Less)

Heat integration of a fermentation-based hydrogen plant connected with sugar factory

The paper is concerned with heat integration of a conceptual hydrogen plant connected with a sugar factory. The sugar factory serves as a source of sucrose-containing thick juice for the hydrogen plant, where this feedstock is processed to hydrogen. Moreover, this connection gives an opportunity to utilize waste heat from the sugar factory. Hydrogen is produced by two-stage fermentation, that is, thermophilic fermentation followed by photofermentation. The gas mixture obtained in the two process stages is supplied to the gas separation system, composed of absorbing and stripping columns for circulating amine solution, to separate hydrogen from carbon dioxide. Using Pinch Technology and considering sugar factory with its CHP plant as an energy source, the hydrogen plant is heat-integrated to minimise the energy consumption. (Less)

Water and energy management in the sugar industry.

Publisher Summary This chapter presents that, in recent decades, world output of sugar has tended to exceed demand causing a surplus situation in the world sugar market so that investments in new sugar factories are very rare. For economic and environmental reasons, however, there is a constant need for reconstruction of sugar factories. The dominant trend is to increase the production rate and take advantage of technological advances in sugar production and environment protection. Energy efficiency may be an important issue in factory reconstruction as the fuel cost in some cases is of the order of several per cent of the cost of sugar production; fuel burning in the power house is usually responsible for a major part of atmospheric emissions. Consequently, sugar factory retrofit typically includes improvements in the factorys energy system to reduce fuel consumption. As water and steam are used as energy carriers, improvements in the energy system may generate opportunities for improvements in water management. Apart from that, factory reconstruction measures aimed at reducing water consumption and wastewater discharge are required to satisfy environmental regulations that are becoming increasingly stringent. A retrofit strategy that is of particular interest to sugar factory operators involves reducing energy consumption by improving heat recovery and reducing water consumption by optimizing the throughput of existing wastewater treatment.

Applications of Process Integration Methodologies in Beet Sugar Plants

Abstract: This chapter discusses the applications of Process Integration methods to the design of energy systems, and water and wastewater systems, of beet sugar plants. Characteristic features of conventional sugar plants based on purification of raw beet juice and evaporating crystallisation are reviewed, the design of plant retrofit aimed at improvements in energy and water use is discussed, and case studies are presented. A concept of the sugar production process based on cooling crystallisation of raw beet juice is then outlined, and the design of an energy system and a water and wastewater system for a conceptual beet sugar plant employing the new process is discussed.

A Method to Analyse the Motion of Solid Particle in Oscillatory Stream of a Viscous Liquid

A mathematical model of the motion of a solid particle in oscillatory stream of a viscous liquid was set up and analytically solved for Reynolds number in the relative motion Re < 2:0 (Stokes flow) and Reynolds number characterising the liquid stream Re* < 2100 (laminar flow). A computer aided method based on video image processing was applied as an experimental tool to analyse the particle motion and verify the mathematical model.