Effects of air preheating and FGR on PM release and NOx emissions: 2020-21 updates

Recent works on that topic, checked for a Customer, include:

Archan, G., Anca-Couce, A., Buchmayr, M., Hochenauer, C., Gruber, J., Scharler, R., 2021. Experimental evaluation of primary measures for NOX and dust emission reduction in a novel 200 kW multi-fuel biomass boiler. Renewable Energy 170, 1186–1196. https://doi.org/10.1016/j.renene.2021.02.055

Meng, X., Ismail, T.M., Zhou, W., Yan, Y., Ren, X., Sun, R., Abd El-Salam, M., 2021. Numerical study of preheating primary air on pinewood and corn straw co-combustion in a fixed bed using Eulerian-Eulerian approach. Fuel 289, 119455. https://doi.org/10.1016/j.fuel.2020.119455

Meng, X., Zhou, W., Yan, Y., Ren, X., Ismail, T.M., Sun, R., 2020a. Effects of preheating primary air and fuel size on the combustion characteristics of blended pinewood and corn straw in a fixed bed. Energy 210, 118481. https://doi.org/10.1016/j.energy.2020.118481

Pérez-Orozco, R., Patiño, D., Porteiro, J., Larrañaga, A., 2020a. Flue Gas Recirculation during Biomass Combustion: Implications on PM Release. Energy Fuels 34, 11112–11122. https://doi.org/10.1021/acs.energyfuels.0c02086

Pérez-Orozco, R., Patiño, D., Porteiro, J., Rico, J.J., 2020b. The effect of primary measures for controlling biomass bed temperature on PM emission through analysis of the generated residues. Fuel 280, 118702. https://doi.org/10.1016/j.fuel.2020.118702

Raheem, D.G., Yilmaz, B., Kayahan, U., Özdoğan, S., 2020. Effect of Recycled Flue Gas Ratio on Combustion Characteristics of Lignite Oxy-Combustion in a Circulating Fluidized Bed. Energy Fuels 34, 14786–14795. https://doi.org/10.1021/acs.energyfuels.0c02464


BIOFACT Engineering joins the event: “Bringing VALUE to AGROBIOMASS”

We joined the event: “Bringing VALUE to AGROBIOMASS” organized by the AgroBioHeat project to facilitate cooperation on sustainable utilisation of biomass from agriculture and side streams from food production.

All over Europe, there is agricultural production of various crops for food and feed and processing of these crops. This results in a large volume of residual biomass streams that can be utilised for various purposes; however, their current mobilization rates remain generally quite low. These resources have the potential to contribute to the transition from a fossil-based economy to a green economy. Agriculture can also provide additional biomass resources through improved land management practices, e.g. by cultivating new crops on marginal lands. Whatever their origin, these agrobiomass resources can be used for production of energy, chemicals, new food products, pharma, materials, and more. The challenge to realise this potential is in some cases a technological one, that requires innovation and development of new processes and equipment. In many cases, e.g. the use of agrobiomass for heat production, there are already available mature technologies in the market that are ready to go, but their market uptake is hindered by absent value chains and lack of knowledge about available technologies. The Bringing Value to Agrobiomass event addressed this by providing an online matchmaking platform for participants to display their technology, express their technological or material needs, or bring attention to their excess biomass resources in order to find cooperation partners to help utilise them. The ultimate goal was to connect relevant stakeholders to facilitate new collaboration on improved use of all these resources.

Corrosion Atlas Case Studies – focusing on ash fireside effects

Beside slagging and fouling, our approach at BIOFACT engineering is to predict quantitatively the critical gas and/or phases in the flue gas streams, to assess the corrosivity level of the specific fuel (mixture) in the energy plant, depending on operating conditions. Specific cooling models are applied to assess condensation on metal surfaces and corrosivity of deposits formed.

Need a deep dive into corrosion? We recommend the Corrosion Atlas Case Studies.

Which factors influence the solid fuels inorganic composition?

The composition of ash forming matter in the biomass fuels is largely varying and depends on multiple factors, not only the biomass type. For example, for biomass, poor-in-nutrients soils can reduce the plant’s capacity to uptake inorganic substances. It was demonstrated that, in spruce, tree branches and twigs contain a higher content of inorganic matter (especially K, Na, Si) than stem wood. It is also known that delayed harvest in spring can result in a reduced inorganic content (especially K).

In this overview, a summary of twelve factors which can influence the biomass fuels inorganic composition is proposed.

Biomass type

1.     The plant species, e.g. variety, genotype.

2.     The state of the plant development or age, the plant growth cycles/season.

3.     The part of the plant considered (and mixes) such as leaves, bark, stem, fibres, tops.

Soil, climate and agricultural practises

4.     The soil characteristics: type, pH, nutrients or composition, pollutants, water quality.

5.     The type of fertilization or pesticides applied.

6.     The climate of the location: rains, atmospheric pollutants and external environmental factors (E.g. road side vegetation contaminated with salt (road de-icing); biomass from river maintenance; driftwood.)

Harvesting, transport, pre-treatment

7.     The selected harvest date and season.

8.     The collection method, harvesting operations (soil and dust incorporation, machines pollution, biological contamination) and transport conditions (ships, trucks potential contaminations).

9.     The storage type/time, if any, and the drying (or other pre-treatment/upgrading) type/duration, if any.

10.  The size reduction e.g. the fineness of the fuel or particles size distribution.

Analyses of the samples

11.  The material sampling method and its representativeness (sampling standards).

12.  The ashing method and the ashing temperatures (production of the ash sample to analyse) as well as the analytical instrumentation used for the ash composition analyses (errors theory).

These factors can influence the inorganic matter content of each biomass, that is why each fuel is different.

It might be complex for producers to control those factors, especially for low-grade or opportunity fuels. Detailed compositional data for the specific fuel to be processed are needed and it is not recommended to consider literature data.

In our thermochemical simulations, we study the ash behaviour of the specific fuel sample, mixture or portfolio, processed in each specific energy plant.

Your Digital Fuel Specialist – in your glasses #2021

Have you ever thought you could have a BIOFACT digital fuel specialist always at your service?

With today’s tool we could make possible to have a online concurrent site investigation, in real-time, with glasses which can connect us with you in an instant, bringing expertise to right where you are.

We could “see what you see” through a live video stream so to provide instant expertise and evaluation on plant operation, with a focus on ash behaviour assessment (slagging, fouling, corrosion), for example during a predicted maintenance or a sudden stop of operations.

Contact us for further details!

Smaller scale RDF/SRF plants – alternative horizontal boiler design for sticky RDF ash

Smaller WtE plants, integrated at different levels of the urban environment, minimise the transportation of waste and ensure the local benefit is maximised from community waste.

In a recent project, a manufacturer developed a rotating boiler with automated cleaning to reduce ash build up on surfaces, specifically for high ash RDF/SRF. The system was designed from 2017 and grated the patented in 2019.

Instead of using an adiabatic furnace linked to a single pass radiant coil and with convective heat batteries equipped with steam/air cleaning nozzles, a standard vertical boiler design is placed horizontally to be able to rotate. This also allows to reduce installations height (reduced construction costs). Continuous rotation more easily removes ash and guarantees performance up to 30% ash fuels. Granular recyclable cleaning media can be used where required (no cleaning systems). Fuel feed, grate speed and combustion air is optimized with a computer vision control system.

Download the boiler design patent

Is this rotary incinerator design more reliable than the most often use, dynamic water-cooled moving grate? It depends on the system size and fuel spectrum. We will wait for additional return on experience from new plants and keep you updated!