Lab sessions in Energy Engineering

To convert an organic material into biochar, various reactors can be used. We like to start on a μg-mg scale with pyrolysis-GC-MS (FID and TCD) and/or TGA analyses of the material. Then we move on to the high-temperature furnace (10-100g) where different gases can be used to control the atmosphere in the process. And lastly, our rotary pyrolysis reactor, which can process 1-6 kg of material depending on its properties.

Equipment

High temperature oven

The furnace is equipped with a gas regulator and several different gases can be connected as atmosphere. The samples are inserted into beakers with lids and a temperature curve is entered with e.g. drying, temperature rise and cooling. Temperature range: 20-1250°C

Rotary Pyrolysis Reactor

The reactor is continuous and material is filled into the feed silo, the reactor is heated to the desired temperature (20-900°C) and the material is fed in, passes the rotary furnace and collected in a container. The reactor runs on nitrogen gas, but other gases are possible. The product gas is analysed and oil and tar condensed before the gases are  

Equipment

Lab-scale fixed bed boiler

Fixed-bed reactor, about 500 g fuel. Temperature sensors in bed and combustion chamber, electric heating. Cyclone separator. Here, combustion on a grate bed is simulated with different air supply and temperatures.

High temperature oven

Oven with air as atmosphere. Temperature range: 20–1250°C. Programmable temperature curve. In the oven, you can also ash samples in the oven.

The following equipment and processes are used for analysis in energy engineering

Microwave oven

For the collection of solid samples such as ash, solid fuels, biochar. etc. The samples are carefully weighed, placed in containers with a cocktail of acids and sealed. The microwave raises the temperature and pressure in the containers, and the process usually takes about 40 minutes with a 20 min temperature ramp and 20 minutes holding time. Then, the samples must be cooled down thoroughly before opening the sample container. 

Energy content

The energy content of a material can be analysed with our Bomb calorimeter. All materials such as food, fuel and biochar can be analysed based on how much energy they have stored. Depending on the density and energy content of the material, a different amount of material is required for each analysis, but it is usually about 1 g of dry sample. 

GC-MS (FID and TCD)

A gas chromatograph with mass spectroscopy as the main detector in which various organic compounds can be detected using a library. Qualitative and quantitative analyses can be done with FID, MS and TCD detectors. It is also possible to connect a pyrolysis unit and analyse the composition of the gas formed during pyrolysis.

TGA and DTG (small)

Thermogravimetric analyses (TGA) are done using a very sensitive scale in the instrument. The sample is inserted into the TGA, the temperature curve is selected and the analysis provides answers to what the weight decrease/gain looks like. Different gases can be used as atmospheres. Temperature range: 20–1600°C. The TGA measures the weight change of the sample as a function of temperature or time under controlled atmosphere (e.g., N₂, CO₂, air). The analysis is used to determine moisture content, volatile substances, carbon and ash content, and to study pyrolysis and combustion processes.

Pressurized TGA

Pressurized TGA allows for simulated industrial conditions, while small TGA allows for rapid testing with small sample quantities.
The derivatogram (DTG) shows the reaction rate and is used to identify reaction steps, activation energies, and reactivity of different materials.

MP-AES

Microwave plasma with atomic emission spectroscopy (ICP-AES). Analyses large parts of the periodic table (not Hg, Cl and S) in fluid samples. Samples in liquid phase and filtered with 45 μm filter as the samples must not contain any particles.

Elemental analysis

Analyse how much C, N, H and S there is in the material. If the ash content is known, the oxygen content can also be calculated.

FTIR spectroscopy

Fourier-transform infrared spectroscopy (FTIR) is used to identify molecular bonds and functional groups in gases, liquids, and solids.
Linked to TGA (TGA–FTIR), the technology can identify emitting gases during pyrolysis or incineration, and provide insight into organic degradation pathways as well as the chemical structure of biochar.

Raman spectroscopy

Raman spectroscopy is used to analyse the structure, carbon order, and chemical bonding of solid materials such as biochar, ash, and slag.
The method is used to determine the degree of graphitization, mineral phases and oxidation states, and complements SEM–EDS.

Integrated process understanding 

Together, these methods provide a multidimensional understanding of thermal processes:

• TGA/DTG – mass changes and reaction kinetics
• FTIR – Gas Phase Composition and Functional Groups
• Raman – structure of the solid phase and mineral changes

This combination links experimental observations to thermochemical modelling and is used to optimise processes in energy recovery, biochar production, metallurgy and resource recovery.

Incubator

Can be used to have gas supply, light, stirring and regulate temperature during trials. Can be used e.g. to grow algae. There are 12 ports for gas supply. 

Leaching methods

We can perform different leaching methods depending on what is requested, but in the first place we use chemical fractionation:

Chemical fractionation is a step-by-step leaching method in which three different solvents are used: Step 1; deionized water 24 h, Step 2; 1M ammonium acetate 72 h and lastly 1M HCl for 48 h. The sample before leaching, the three leaching solutions and the solid remainder of the sample are analysed. The size of the sample quantity depends on the properties and composition of the material.

SEM-EDS: Electron Microscopy- Energy dispersive X-ray spectroscopy (to see how metals and alkali are located)

At the Energy Lab, experimental studies are combined with computational thermochemistry, advanced modelling and simulation to analyse and optimise high-temperature processes in energy recovery, biochar production, and pyro-, hydro- and extraction metallurgy.

The FactSage, ChemApp, HSC Chemistry, Aspen Plus tools are used to predict chemical equilibrium, reaction kinetics, heat and mass transport, and system integration. With these tools, we can model slag behaviour, metal distribution, corrosion and energy flows, as well as optimize processes for metal and nutrient recycling, biochar production and resource processing.

Through connection to life cycle assessment (LCA), the energy and resource efficiency, climate impact and circularity of the processes are evaluated.

The research is conducted in close collaboration with industry in the energy, steel, pulp and paper, metal, battery, nutrient and recycling sectors, and contributes to the development of sustainable, circular and carbon-neutral processes for the industry of the future.