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The purpose of this study was to evaluate the feasibility of using residues from cooking oil production to produce alternative biochar fuels along with optimizing the pyrolysis process. The work consisted of carrying out the pyrolysis process at varying temperatures and holding times at the final temperature, and then evaluating the energy potential of the materials studied. Taking into account aspects of environmental emissions, the content of selected oxides in the flue gases generated during the combustion of cakes and the biochar obtained from them was evaluated. Plant biomass derived from a variety of oilseeds, i.e., fennel flower (Nigella sativa L.), rapeseed (Brassica napus L. var. Napus), flax (Linum usitatissimum L.), evening primrose (Oenothera biennis L.), milk thistle (Silybum marianum L. Gaertn.) and hemp (Cannabis sativa L.), was used to produce biochar. The experimental data have shown that the obtained biochar can have a calorific value of nearly 27 MJ kg−1. The use of pyrolysis allowed for a maximum increase in the calorific value of nearly 41% compared to non-thermally processed cakes and a several-fold decrease in carbon monoxide, nitrogen oxides and sulfur dioxide emissions. According to these results, it can be concluded that the pyrolysis process can be an attractive method for using residues from the production of various cooking oils to produce alternative biofuels, developing the potential of the circular economy. [ABSTRACT FROM AUTHOR]

The article discusses the findings related to the calorific value as well as the explosion and combustion parameters of dust from the raw biomass of fruit trees, i.e., apple, cherry, and pear branches, and from biochars produced using this type of biomass during pyrolysis processes conducted under various conditions. The plant biomass was thermally processed at 400, 450, or 500 °C for a duration of 5, 10, or 15 min. The study aimed to identify the calorific value of the biomass obtained from waste produced in orchards and to estimate the explosion hazard during the processing of such materials and during the storage of the resulting solid fuels. Tests were conducted to assess the total contents of carbon, ash, nitrogen, hydrogen, and volatile substances as well as the calorific value. The findings show a significant effect of the thermal transformation of fruit tree branches on the calorific value of the biochars that were produced. It was found that the mean calorific value of all of the biochars was increased by 62.24% compared to the non-processed biomass. More specifically, the mean calorific values of the biochars produced from apple, cherry, and pear branches amounted to 27.90, 28.75, and 26.84 MJ kg−1, respectively. The maximum explosion pressure Pmax measured for the dust from the biomass and for the biochars was in the range 7.56–7.8 and 7.95–11.72 bar, respectively. The maximum rate of pressure rose over time (dp/dt)max in the case of the dust from the biomass, which was in the range of 274.77–284.97 bar s−1, and the dust from biochar amounted to 282.05–353.41 bar s−1. The explosion index Kst max measured for non-processed biomass and biochars was found to range from 74.46 to 77.23 and from 76.447 to 95.77 bar s−1, respectively. It was also shown that a change in the temperature and duration of the pyrolysis process affected the quality of the biochars that were obtained. The findings show that pyrolysis, as a method of plant biomass processing, positively affects the calorific value of the products and does not lead to an increased risk of explosion during the treatment and storage of such materials. It is necessary, however, to continue research on biomass processing in order to develop practices that adequately ensure safety during the production of novel fuels. [ABSTRACT FROM AUTHOR]

This article presents the results of a two-year study investigating the effects of the fertilization of soil, with biochar and ash from plant biomass, on selected properties of the pyrolysis products obtained from basket willow (Salix viminalis L.) and giant miscanthus (Miscanthus x giganteus). The study was designed to determine whether soil enrichment through the use of organic fertilizers (ash added at the rate of 1.5 t ha−1, biochar added at the rate of 11.5 t ha−1 and a combination of them) in the cultivation of energy crops would affect the quality of pyrolysates obtained from these plants. The research goal was to use biochar and biomass ash to produce high-quality pyrolysates with fertilizing potential. The aboveground parts of the plants were subjected to the pyrolysis process, which was carried out in constant conditions, i.e., a temperature of 500 °C and duration of 10 min. The pyrolysates obtained were examined for their pH value, the content of absorbable forms of phosphorus (P2O5), potassium (K2O) and magnesium (Mg), as well as total carbon and the total content of selected macro- and micro-elements. The results of the current study show the beneficial effects of these soil fertilizers, reflected by the high quality and enhanced mineral contents of the biochars obtained. The highest total increase in the contents of absorbable forms of P, K and Mg was found in the pyrolysis products from basket willow fertilized with ash alone, amounting to 21.6% in relation to the pyrolysates from the control sample. As for the pyrolysates from the biomass of giant miscanthus, the greatest total increase in the contents of the elements, amounting to 44.4%, was identified when biochar and ash were used in combination. Soil amendments such as biochar and ash used for growing bioenergy crops can alter the aboveground plant quality. The subsequent pyrolysates created from these plants may be enriched and can be an alternative to mineral fertilizers. Natural amendment, such as high-quality pyrolysates, can be used in the cultivation of many plants. Additionally, conversion of plant biomass into pyrolysates is important for the environment, affecting the balance of carbon in the atmosphere through its capture and storage in a stable form outside the atmosphere, e.g., in soil. [ABSTRACT FROM AUTHOR]