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Renewables-based drying technology for cost-effective valorisation of waste from the food processing industry

Periodic Reporting for period 3 - DRALOD (Renewables-based drying technology for cost-effective valorisation of waste from the food processing industry)

Reporting period: 2021-01-01 to 2021-06-30

The EU27 annually generates 90 million tonnes of food waste, implying a major environmental problem, Experts have highlighted the need for generation of food waste valorisation and re-use strategies to produce higher value and marketable products, leading to a higher adoption of circular economy strategies by the food processing sector.
This project identifies an excellent business opportunity in promoting the valorisation for reuse of certain wastes from the food and drink processing industry, characterised by:
- A high content of water (>80%), which has traditionally been a drawback for reuse, since this type of waste has a very rapid fermentation and degradation and is enormously inefficient for transport and storage.
- Containing highly valuable nutritional ingredients, thus widely validated by the scientific community as rich in functional biocompounds, demanded by the nutraceutical and pharmaceutical industry.

Our process offers an environmental-friendly path for valorisation of food processing waste, savings CO2 emissions to the atmosphere with reference to a drying system powered by natural gas. Drying of high-water content waste brings additional climate change related benefits, from the perspective of reducing the volume of road transport from the reduction of an average 65% of mass of the product, after being dried. Additionally, DRALOD will also have an important beneficial impact by enabling the reuse of food processing waste, as a valorised product for animal feeding and/or functional ingredients for the nutritional and the pharma industries.
This project mat lead to the following benefits to the society:
- Contributing to protect society against the adverse effects of global warming, by contributing to address the challenge of shifting air drying processes to clean energy and of reducing the volume of road shipments related to waste management in food processing.
- Contributing to the generation of jobs in emerging sectors such as waste valorisation, as well as in consolidated sectors such as renewable energies, in particular solar and biomass industrial segments.
- Contributing to preserve ecosystems by providing alternative methods that displace landfilling.

The main technical objectives of this project are:
- To design, implement and validate an energy recovery system, optimised to DRALOD plant´s operating conditions
- To implement a biomass heating system with high flexibility concerning both type of fuels / fuel quality and mode of operation to enable low operational costs as an auxiliary heat source.
- To design, implement and validate a proprietary smart controller unit for a combined solar-biomass drying plant based on thermodynamically simulation of multidomain dynamic system
- To design DRALOD drying plant, as the integration of these subsystems with the drying tunnel and auxiliary systems.
- To commission a pilot plant with a capacity of 35,000ton waste/year from >80% to <15% water content and to run a demonstrator to assess the plant performance from a financial, operational and environmental perspective.
·Design, implementation and commissioning of DRALOD Pilot plant: a renewables-based low-temperature drying plant. A biomass heating system is optimised to work as an auxiliary heat source in the plant, powered by solar air heating.The pilot plant is located in Chiloeches (Spain) a strategic location near to large food and beverage processing plants. Its operating temperature if of 75ºC. It uses a co-current rotary dryer with double pass trommel.

· The pilot plant is operated during a demonstration period of 9 weeks. It is demonstrated for the drying of different materials including Brewer´s Spent Grain (BSG), orange pulp, beetroot pulp and olive oil by-products. The combination of a 2,500 m2 solar installation with a 1 MW boiler is shown to provide a suitable solar/biomass ratio. This combination allows the percentage of solar contribution to the system to be higher than 50%, allowing significant savings in the biomass consumed. The solar system meets the production and thermal jump expectations, presenting it as an interesting alternative in the implementation of this type of solar system in low-temperature air entrainment dryers.The temperature of 75ºC in the low-temperature drying process allows efficient drying without altering the composition of certain products.

· A Heat Recovery Unit (HRU) has been designed and implemented as a research scale prototype. It is made up of a scrubber condensation unit that recovers heat from the exhaust air at the dryer output and a heat pump system to upgrade heat from the solar air heating to a usable temperature. It was first tested in laboratory environment in Böras (Sweden). Then it was installed in the DRALOD pilot plant and tested in real industrial environment. The tests show a good energy performance. The HRU can recover about 20 kW heat from the dryer system. The recovered heat is used as heat pump heat source. A full-scale system is about 1 MW, Based on the knowledge gained from these R&D activities, the specifications for a full scale HRU of 1MW, to be operative in a DRALOD pilot plant, have been specified.

· A cost benefit analysis of the DRALOD Pilot plant based on computational models for determination of optimal operational conditions.

· 3 scientific publications in peer reviewed journals.

· Participation in 3 scientific conferences: 6th Central European Biomass Conference (CEBC 2020) Graz-Austria, 29th European Biomass Conference and Exhibition (EUBCE 2020), 23rd Conference on process integration, modelling and optimisation for energy serving and pollution reduction (PRES´20) on-line.

·Participation in industrial exhibitions: A presentation poster of DRALOD project was exhibited at ÖKOTHERM´s attended in Agritechnica 2019, the global leading trade fair for agricultural machinery taking place in Hannover.

·Contributions to two additional scientific conferences accepted, they have been postposed due to the covid-19 pandemia, and are expected to take place in 2022.

·Creation of dissemination tools including website frequently updated with news on project progress.
DRALOD proposes progress beyond the state of the art for delivering a new drying plant concept designed for the European markets where climatological conditions imply a need for sophisticated and energy efficient heating systems and a technical challenge in the optimisation of the combined operation to the level of achieving cost-effectiveness in the drying of waste.
DRALOD proposes an innovative low-temperature air drying plant with the core advantages of being:
- Sustainable: using renewable energy sources (solar and biomass air heating) as well as heat recovery for increased energy efficiency.
- Suitable for the preservation of nutritional ingredients: using a temperature process demonstrated to be reliable for eliminating pathogens while preserving nutrient content.
- Suitable for valorisation of waste with a high content of water: enabling a water content reduction from approx. 80% to less than 15%, extended shelf life from approx. 7 days to 1 year), thus increasing the economic feasibility of their storage and transport.
- Cost effective: with optimised operational cost, enabling financial feasibility in the drying of low price products.
Partners at the project Kick-Off Meeting
DRALOD Pilot Plant in operation