Test bench for developing and testing of automatic and manually loaded biomass boilers in accordance with DIN EN 304 and DIN EN 303-5 using a special controllable heat dissipation system for the simulation of practical operation. Fraunhofer IBP/Bernd Müller

The special device pictured on the cover is accredited by the German Accreditation Body (DAkkS) and, in addition to the boiler (combustion system), consists mainly of a high-precision weighing machine, an exhaust gas measurement set and delivery system with regulated delivery pressure, a controllable heat dissipation system for simulating the real operation, a control, monitoring and data acquisition system as well as an exhaust gas analyzer for cold- and heated gas sampling. Using this novel technical equipment, not only research and normative testing of automatic and manually loaded biomass boilers in accordance with DIN EN 304, DIN EN 303-5, and Machinery Directive 2006/42 will be carried out, but also the combustion process with regard to energy and emissions flows will be analyzed in detail.

In comparison to the common laboratory apparatus, the combustion and exhaust gas treatment technologies can be developed target oriented by using this novel testing set-up. Moreover, fuels with high heterogeneity can be more accurately investigated for their energy content and the potential for formation of dust (organic and inorganic fine particles) and gaseous pollutant emissions (NO_x, SO₂, HCl, dioxins, and furans).

Thanks to the self-developed control and data acquisition system, all results can be calculated and monitored online while being visualized accordingly and saved in a big data cloud.

Mixing of biomass in biogas plants requires high energy input. A comprehensive computational fluid dynamics method to assess the mixing quality in biogas digesters is described and validated. Conclusions about positioning and working methodology of the mixers are indicated and can constitute the basis of rules and guidelines for the design and optimization of biomass mixing systems.

Partially upgraded biogas is a potential fuel for agricultural vehicles. Experimental investigations on a single-cylinder combustion engine and model-based analysis of a water scrubbing process show that the idea of decentralized utilization of biogas represents a promising approach for cost-efficient farm-based biogas upgrading.

A decentralized combustion system with an integrated exhaust gas treatment unit in biomass-fueled boilers was developed. A significant reduction of gas and dust emissions in all operating phases for thermal utilization of biomass in gasification boilers is achieved, ensuring compliance with the future technical emission requirements without further costly secondary measures for exhaust gas treatment.

Flexibilization strategies for biogas plants are the key to their success in the energy transition to renewable sources. In the ThermoFlex process, controlled operation of a thermophilic secondary digester following a mesophilic main digester allows effective, flexible heat storage in the secondary digester for digester heating and external heat utilization without disturbing its process biology.

Exergy, exergoeconomic and enviroeconomic analyses made for a micro-CHP system based on a biomass boiler and a steam engine revealed that it has relatively low exergy efficiency compared to similar systems described in the literature. The considered system has improvement potential in terms of exergy efficiency, focusing on the boiler.

A filter concept was developed and tested with the goal to reduce soot, NO_x, and SO_x emissions in one process step at low temperature levels (150–200 °C). The developed filter is able to meet the strict emission limit values that will be set for combined heat and power plants in the future.

Chemical and physical analyses were carried out on different ash fractions of diverse small biomass boilers, enabling a comparison of the boilers and fuels used. Chemical composition and physical properties were shown to strongly depend on the type of the ash, the fuel, and the boiler. The investigations focused on assessing whether the ashes can be classified as fertilizer and not as waste.

Several steam storage systems to achieve a controllable power generation from biomass combustion plants are available. These systems are evaluated according to the boundaries of the plants as well as the electricity grid and market demands. An adapted analytic hierarchy process with implementation of the Delphi survey was performed to identify the most suiting storage device.

Photosynthesis-based microalgal-mediated carbon dioxide capture and usage is a promising approach to reduce the amount of CO₂ in the atmosphere and provide a long-term and sustainable solution to global warming. To this end, freshwater microalgae Neochloris oleoabundans was cultured and the biomass and lipid productivity and lipid contents under different conditions were investigated.

For dehydration of castor oil, the NaHSO₄/MCM-41 catalyst was synthesized by supercritical impregnation, which was advantageous to improve NaHSO₄ dispersion and to boost the interaction between NaHSO₄ and the catalyst MCM-41. Coke formation and NaHSO₄ leaching were retarded. Conversion, selectivity, and stability of the NaHSO₄/MCM-41 catalyst could be significantly enhanced.

Butyl acetate is an important ester with numerous applications. The applicability of reactive distillation in the catalytic esterification of acetic acid with n-butanol was investigated with low-cost, readily available, and reusable uncoated clay beads as column packing material. High acid conversion in shorter reaction time was achieved by reactive distillation compared with the batch process.

For removal of NO from flue gas, an innovative low-temperature method was developed based on a heterogeneous Fenton-like process using Fe-containing polyoxometalates as heterogeneous catalyst. An average removal efficiency of > 90 % was achieved under optimized conditions. The synthesized Fe^IIIAspPW complex was employed to activate H₂O₂ and investigate the effects of various factors on NO removal.

Selective extraction of metal ions by reactive solvent extraction is a commonly used process in hydrometallurgy. The physical mass transfer is superimposed by a complexation reaction, which solubilizes the ionic solute into the organic phase. Hydrodynamics and mass transfer in an agitated Kühni miniplant column for the reactive extraction of zinc with the liquid cation-exchanger D2EHPA are evaluated.

Fluid catalytic cracking (FCC) is one of the most important processes in refineries. The main part of the FCC process is the reaction and regeneration in which the catalyst is being circulated. In this work, the attrition resistance, surface properties, and catalyst loss have been investigated on a domestic refinery with residue fluid catalytic cracking catalysts in both fresh and spent forms.

Process integration plays a key role in chemical process industries in terms of minimizing waste and energy demands. Simultaneous design and control is demonstrated for a complex ternary reactive distillation column with inert material. The optimization problem is formulated as mixed-integer dynamic optimization problem. An improved process design and control is achieved by solving this issue.

Liquid maldistribution in packed columns cannot be predicted adequately so far. Such maldistribution in random packing is experimentally investigated with varying experimental and operating parameters. Distribution spectra identify the maldistribution phenomena wall flow and liquid channeling. Evaluations by means of the maldistribution factor illustrate the degree of nonuniform distribution.

Two types of innovative hybrid nanomaterials, namely, graphene oxide-manganese ferrite and titania nanotube-manganese ferrite, with enhanced properties were synthesized and applied as adsorbent to remove As(V) from water. A high level of reusability after undergoing a simple desorption process coupled with the promising adsorption capacity make the hybrid nanomaterials highly potential.

Undesired release of particles from bulk materials occurring in material-handling processes can present a hazard to humans and the environment. Dust formation tendency as an important material property depends on the specific type of stress. A semi-empirical forecast parameter was derived based on experimental analyses with a UNC dustiness tester and used to develop forecast formulas.

Lowering the viscosity of heavy crude oil is required for its pipeline transportation. Naphthenic acids in crude oil can self-assemble with tertiary amines to form CO₂-switchable surfactants that can form low-viscosity crude oil-water (O/W) emulsions, which are readily demulsified in the presence of CO₂. This provides a new concept for the pipeline transportation of heavy crude oil.

High-energy-density materials are at the frontier of energetic materials research. A continuous-flow microreactor allows the successful synthesis of oxygen-containing 5,5′-azotetrazolate salts through metathesis reactions. The present procedure is efficient and easy to handle, and oxygen-containing 5,5′-azotetrazolate salts can be obtained in minutes in high yield.