Timo Laukkanen

• Dr. Sc.(Tech.)
• Researcher at Aalto University

Thermal energy storage (TES) offers a practical solution for reducing industrial operation costs by load-shifting heat demands within industrial processes. In the integrated Thermomechanical pulping process, TES systems within the Energy Hub can provide heat for the paper machine, aiming to minimize electricity costs during peak hours. This strateg...

Phase change materials can improve the energy density of thermal energy storages (TES) by using the latent heat of melting, but they cannot typically operate efficiently in long-term TES. A unique way to store the latent heat for long-term can be achieved with erythritol-polyelectrolyte mixture, which exploits supercooling, glass transition and col...

Preface Novel high-performance veneer products by effective drying and nano-coating (VERYCOAT) was performed in 2019-2022. The project was funded by Business Finland with collaboration with industry partners. The research partners were VTT and Aalto University's departments Bioproduct and Biosystems and machine design. The industry partners are sho...

Thermo-mechanical Pulping (TMP) is one of the most energy-intensive industries where most of the electrical energy is consumed in the refining process. This paper proposes the energy-saving refining optimization strategy by integrating the machine learning algorithm and heuristic optimization method. First, refining specific energy consumption (RSE...

Bioenergy with carbon capture and storage (BECCS) is one of the key negative emission technologies (NETs). Large-scale implementation of BECCS has been criticized of the associated increase in land use. The existing large Nordic pulp and paper production units enable BECCS deployment without additional land use, as they currently release large amou...

The LuxTurrim5G project is built on integrating different types of sensors and equipment that have been integrated into light poles in order to build new data-driven services. One additional service could be to harvest the waste heat produced in the electrical devices in the pole. In this research, we developed an intelligent model for heat transfe...

Data from two thermo-mechanical pulp mills are collected to simulate the refining process using deep learning. A multilayer perceptron neural network is utilized for pattern recognition of the refining variables. Results show the impressive capability of artificial intelligence methods in refining energy simulation so that the correlation coefficie...

Load forecasting is critical for a variety of applications in modern energy systems. Nonetheless, forecasting is a difficult task because electricity load profiles are tied with uncertain, non-linear, and non-stationary signals. To address these issues, long short-term memory (LSTM), a machine learning algorithm capable of learning temporal depende...

A refining model is developed to analyses the refining process’s energy efficiency based on the refining variables. A simulation model is obtained for longer-term refining energy analysis by further developing the MATLAB Thermo-Mechanical Pulping Simulink toolbox. This model is utilized to predict two essential variables for refining energy efficie...

The city of Espoo, Finland is planning to develop Kera as a green suburb with high level of energy efficiency and low CO2 emissions, using a high share of renewable energy and recycled or reused energy. For reaching this target, in this study, renewable energy resources such as solar, wind and waste heat are investigated for the study region. Two d...

Thermo-mechanical pulping (TMP) as a subdivision of the refiner-based mechanical pulping is one of the most energy-intensive processes in which the main procedure is carried out during the refining process. In this study, a simulation model is developed to estimate the energy efficiency of the refining process for the long-term period. A Simulation...

In the pulping industry, thermo-mechanical pulping (TMP) as a subdivision of the refiner-based mechanical pulping is one of the most energy-intensive processes where the core of the process is attributed to the refining process. In this study, to simulate the refining unit of the TMP process under different operational states, the idea of machine l...

The energy coming from solar radiation could be harvested and transformed into electricity through the use of solar-thermal power generation and photovoltaic (PV) power generation. Placement of solar collectors (thermal and photovoltaic) affects the amount of incoming radiation and the absorption rate. In this research, new correlations for finding...

A key challenge in prevention of global warming is how to increase energy efficiency, to be able to deal with increased fossil CO2 emissions from rising energy usage. Increasing energy efficiency will decrease energy usage and is in a key role in emission mitigation. The focus is the pulp and paper industry, which is energy-intensive. Development o...

In this article, we show how a revised district heat network control strategy can be employed to utilize the storage capabilities of the network. An optimization problem is formulated, with minimum operating costs as the objective. Allowing the district heat supply temperature to vary freely within given boundaries results in approximately 2% reduc...

Heat transfer between different processes or inter-plant heat integration can be seen as an efficient way to cost-efficiently improve the energy efficiency of a system of different processes. Nanofluids are a new type of heat transfer fluids, in which particles with size of 1–100 nm are suspended in a liquid. Nanosized particles can cause considera...

The production of precipitated calcium carbonate (PCC) from steel slag has been proposed as a potential method of simultaneously reducing the CO2 emissions from the steelmaking process and turning its waste stream into a valuable product. On average the production of one ton of steel results in two tons of CO2 emissions and 600 kg of slag. Globally...

This paper examines a simulation of Jatropha curcas shell within an entrained flow gasifier to predict the composition of gaseous product. Since there is no available data of Jatropha shell experiment, we validated the model using other biomass: rice husk and sawdust. The validation results showed that the model agreed with the experimental data of...

Improving energetic performance is a key factor in making societies more sustainable. One way to analyze energetic performance is to use methods based on the second law of thermodynamics. Exergy analysis is such a method. With exergy analysis thermodynamic losses of the studied system can be found. For a specific process decreasing the exergy losse...

Soot sludge is a waste stream of chemical industry. It is formed in a gasification process of fuel oil which is part of the production chain of formic acid and hydrogen peroxide. The moisture content of the soot sludge is 95% (w.b.) after the process. At present, the soot sludge is combusted at a combined heat and power (CHP) plant using heavy fuel...

The European Union's goal is to increase the share of renewable energy sources to 20 per cent and that of liquid biofuels for transport to at least 10 per cent by 2020. Liquid biofuels for transport are, for example, biodiesel and bioethanol. Their use is not assumed to increase CO2-emissions in the atmosphere. However, production processes of tran...

Biomass fast pyrolysis (BFP) is a promising pre-treatment technology for converting biomass to transport fuel and in the future also for high-grade chemicals. BFP can be integrated with a municipal combined heat and power (CHP) plant. This paper shows the influence of BFP integration on a CHP plant's main parameters and its effect on the energetic...

The goal of biofuel production is to partially replace fossil fuels in energy generation and transport. For the evaluation of biofuel production processes different criteria are applied and usually they include costs, efficiency aspects and emissions. However, evaluation of the energy efficiency of biofuels production is difficult since no general...

Interactive multiobjective optimization methods have provided promising results in the literature but still their implementations are rare. Here we introduce a core structure of interactive methods to enable their convenient implementation. We also demonstrate how this core structure can be applied when implementing an interactive method using a mo...

Improving energetic performance is a key factor in making societies more sustainable. One way to analyze energetic performance is to use methods based on the second law of thermodynamics. Exergy analysis is such a method. With exergy analysis thermodynamic losses of the studied system can be found. Exergy shows the maximum useful work potential tha...

A mathematical model for making quantitative and qualitative predictions regarding the performance of water-cooled photovoltaic/thermal collectors integrated with a building domestic hot water preparation system has been developed. A genetic algorithm has been applied to the model in order to simultaneously find optimal design parameters affecting...

A mathematical model for making quantitative and qualitative predictions regarding the performance of water-cooled PV/T systems is presented. The hypothesis of the research is that design parameters affecting photovoltaic/thermal collectors’ feasibility have to be optimized simultaneously in order to choose among a set of conflicting solutions the...

A domestic thermoelectric cogeneration system (DTCS) is a noiseless and maintenance-free method of on-site micro-cogeneration, with no moving parts. This paper contributes to the research by characterizing, modeling and assessing the performance of a DTCS, where thermoelectric modules are integrated directly in the combustion chamber of a wooden-pe...

Fossil fuels applied in energy generation-, transport- and refinery processes can be replaced by biofuels. This offers plenty processing options for biomass resources such as thermo-chemical. For process evaluation different criteria is applied, usually including costs, energy efficiency and CO2 emission. However, comparative evaluation of the ener...

In order to react on future expected increased competition on restricted biomass resources, communal combined heat and power (CHP) plants can be integrated with biomass upgrading processes that add valuable products to the portfolio. In this paper, outgoing from a base case, the retrofit integration of production of wood pellets (WPs), torrefied wo...

The use of biofuel as a road transportation fuel is increasing throughout Europe and other industrialized countries to reduce greenhouse gas emissions and to improve the security of fuel supply. Bio-oil produced from biomass pyrolysis is renewable liquid fuel and can also be used for production of chemicals. Upgrading of the bio-oil to transportati...

Heat exchanger network synthesis (HENS) has been an active research area for more than 40 years because well-designed heat exchanger networks enable heat recovery in process industries in an energy- and cost-efficient manner. Due to ever increasing global competition and need to decrease the harmful effects done on the environment, there still is a...

Process plants are typically divided into different process parts having specific processing tasks with possibly different ownership. Heat integration between these processes can increase the energy- and economic efficiency for both the overall plant and the individual processes. In this paper we present a heat exchanger network synthesis MINLP-mod...

A prediction for product gases of Jatropha curcas Linn (JCL) oil cake gasified in the entrained flow reactor is studied in this paper. ASPEN PLUS commercial software is used to carry out the simulation using Gibbs free energy minimisation with equilibrium phase. A series of simulations and analyses have been carried out to investigate the compositi...

In this work we present a multi-objective approach to optimising configurations of an oxyfuel power plant process. The approach solves an optimisation model based on simulation results using an interactive multi-objective optimisation method, NIMBUS, which is implemented in GAMS. The optimisation model of the oxyfuel power plant process is based on...

In order to estimate the heat of condensation of fast pyrolysis product of woody biomass a model to be used in the chemical process simulation software Aspen+ has been developed based on the composition of wood fast pyrolysis product. A simulation model for biomass fast pyrolysis was developed. The results obtained are in good accordance with value...

In this work we present a bilevel optimization method for simultaneous synthesis of heat exchanger networks (HENS). The results show that compared to a similar method using the same superstructure the presented method can provide comparative solutions to HENS problems with reduced calculation effort especially for larger problems. Hence the value o...

In order to react on high future biomass prices, communal CHP plants can be integrated with biomass upgrading processes that add valuable products to the portfolio. In this paper, outgoing from a base case, we simulate the retrofit integration of wood fast pyrolysis slurry, torrefied wood pellets and wood pellets production with an existing wood-fi...

This paper investigates the influence of the integration of communal biomass-fired combined heat and power plants with wood-pyrolysis on the plant’s energy balance and product distribution. Further the proposed integration concept’s influence on the environmental performance of the connected district heating network is pointed out. The environmenta...

In this work we present a multi-objective approach to heat exchanger network synthesis. The approach solves a modified version of the Synheat model using an interactive multi-objective optimisation method, NIMBUS, which is implemented in GAMS. The results obtained demonstrate the potential of interactive multi-objective optimisation.

The integration of different energy systems, e.g., industrial and municipal, is potentially important for the efficient utilization of energy. It is important that the tools for analysing this type of integration can handle the energy systems on different levels, e.g., regional, site, plant and process levels. In this work, a framework for investig...