Evaluation of the Heat Produced by the Hydrothermal Liquefaction of Wet Food Processing Residues and Model Compounds

Hydrothermal liquefaction has proven itself as a promising pathway to the valorisation of low-value wet food residues. The chemistry is complex and many questions remain about the underlying mechanism of the transformation. Little is known about the heat of reaction, or even the thermal effects, of the hydrothermal liquefaction of real biomass and its constituents. This paper explores different methods to evaluate the heat released during the liquefaction of blackcurrant pomace and brewers’ spent grains. Some model compounds have also been evaluated, such as lignin, cellulose and glutamic acid. Exothermic behaviour was observed for blackcurrant pomace and brewers’ spent grains. Results obtained in a continuous reactor are similar to those obtained in a batch reactor. The heat release has been estimated between 1 MJ/kg and 3 MJ/kg for blackcurrant pomace and brewers’ spent grains, respectively. Liquefaction of cellulose and glucose also exhibit exothermic behaviour, while the transformation of lignin and glutamic acid present a slightly endothermic behaviour.

THE USE OF ULTRASOUND IN THE PREPARATION OF THE CATALYST Ru/HPS MN 100 AND ITS ACTIVITY IN THE PROCESS OF HYDROGENATION OF XYLOSE AND LACTOSE

В работе рассмотрена возможность использование ультразвука при получении рутений содержащей каталитической системы Ru/СПС MN 100. Проведено кинетическое тестирование данного катализатора и сравнение его активности с таким же катализатором, но синтезированным без использования ультразвука, в процессе гидрирования ксилозы и лактозы до соответствующих полиолов - ксилита и лактита. Процесс гидрирования осуществлялся в реакторе периодического и непрерывного действия при оптимальных условиях (температуре, концентрации моно- и дисахарида, парциальном давлении водорода, скорости подачи водного раствора ксилозы и лактозы и скорости подачи водорода). Установлено, что ультразвуковая обработка рутениевого катализатора способствует повышению его активности, что отражается на увеличении конверсии моно- и дисахарида при проведении процесса в периодических условиях, при этом практически не происходит изменения конверсии субстратов при их гидрировании в реакторе проточного типа. The paper considers the possibility of using ultrasound in the production of ruthenium-containing catalytic system Ru/SPS MN 100. Kinetic testing of this catalyst was carried out and its activity was compared with the same catalyst, but synthesized without the use of ultrasound, in the process of hydrogenation of xylose and lactose to the corresponding polyols - xylitol and lactite. The hydrogenation process was carried out in a periodic and continuous reactor under optimal conditions (temperature, concentration of mono - and disaccharide, partial pressure of hydrogen, the rate of supply of an aqueous solution of xylitol and lactite and the rate of supply of hydrogen). It was found that ultrasonic treatment of the ruthenium catalyst contributes to an increase in its activity, which is reflected in an increase in the conversion of mono - and disaccharide during the process under periodic conditions, while there is practically no change in the conversion of substrates during their hydrogenation in a flow-type reactor.

Characteristics of Biogas Production from Organic Wastes Mixed at Optimal Ratios in an Anaerobic Co-Digestion Reactor

This study determined the optimal mixing ratio of food waste and livestock manure for efficient co-digestion of sewage sludge by applying the biochemical methane potential (BMP) test, Design Expert software, and continuous reactor operation. The BMP test of sewage sludge revealed a maximum methane yield of 334 mL CH4/g volatile solids (VS) at an organic loading rate (OLR) of 4 kg VS/(m3·d). For food waste, the maximum methane yield was 573 mL CH4/g VS at an OLR of 6 kg VS/(m3·d). Livestock manure showed the lowest methane yield. The BMP tests with various mixing ratios confirmed that a higher mixing ratio of food waste resulted in a higher methane yield, which showed improved biodegradability and an improved VS removal rate. The optimal mixing ratio of 2:1:1 for sewage sludge, food waste, and livestock manure was determined using Design Expert 10. Using continuous co-digestion reactor operation under an optimal mixing ratio, greater organic matter removal and methane yield was possible. The process stability of co-digestion of optimally mixed substrate was improved compared with that of operations with each substrate alone. Therefore, co-digestion could properly maintain the balance of each stage of anaerobic digestion reactions by complementing the characteristics of each substrate under a higher OLR.

Identification of active catalysts for the acceptorless dehydrogenation of alcohols to carbonyls

Acceptorless dehydrogenation into carbonyls and molecular hydrogen is an attractive strategy to valorize (biobased) alcohols. Using 2-octanol dehydrogenation as benchmark reaction in a continuous reactor, a library of metal-supported catalysts is tested to validate the predictive level of catalytic activity for combined DFT and micro-kinetic modeling. Based on a series of transition metals, scaling relations are determined as a function of two descriptors, i.e. the surface binding energies of atomic carbon and oxygen. Then, a volcano-shape relation based on both descriptors is derived, paving the way to further optimization of active catalysts. Evaluation of 294 diluted alloys but also a series of carbides and nitrides with the volcano map identified 12 promising candidates with potentially improved activity for alcohol dehydrogenation, which provides useful guidance for experimental catalyst design. Further screening identifies β-Mo2N and γ-Mo2N exposing mostly (001) and (100) facets as potential candidates for alcohol dehydrogenation.