Most pyrolysis reactors require small sizes of biomass particles to achieve high-quality products. Moreover, understanding the usefulness of high-pressure systems in pyrolysis is important, given the operational challenges they exhibit specific to various biomass materials. To actualize these aspects, the authors first checked previous reviews involving pyrolysis on different biomass and different conditions/situations with their respective objectives and subsections. From these already existing reviews, the team found that there has not been much emphasis on high-pressure fast pyrolysis and its potential in biomass conversion, showing that it is a novel direction in the pyrolysis technology development. Therefore, this review aims to shed more light on high-pressure fast pyrolysis, drawing from (a) classification of pyrolysis; (b) reactors used in fast pyrolysis; (c) heat transfer in pyrolysis feedstock; (d) fast pyrolysis parameters; (e) properties/yields of fast pyrolysis products; (f) high pressure on pyrolysis process; (g) catalyst types and their application; and (h) problems to overcome in the pyrolysis process. This review increases the understanding regarding high-pressure fast pyrolysis. An attempt has been made to demonstrate how high-pressure fast pyrolysis can bring about high-quality biomass conversion into new products. It has been shown that fluidized bed (bubbling and circulating) reactors are most suitable and profitable in terms of product yield. The high-pressure, especially combined with the fast-heating rate, may be more efficient and beneficial than working under ambient pressure. However, the challenges of pyrolysis on a technical scale appear to be associated with obtaining high product quality and yield. The direction of future work should focus on the design of high-pressure process reactors and material types that might have greater biomass promise, as well understanding the impact of pyrolysis technology on the various output products, especially those with lower energy demands. We propose that the increase of process pressure and biomass particle size decrease should be considered as variables for optimization.

Background There is evidence that metabolic syndrome (MS), as a cluster of acute coronary syndrome (ACS) risk factors, is associated with increased left ventricle mass index (LVMI). According to the 2009 IDF criteria of MS diagnosis, elevated waist circumference (≥94 cm in M, ≥80 cm in F), as a determinant of abdominal obesity (AO), is not an obligatory component of MS. Little is known about the relation of abdominal obesity to LVMI in pts with ACS. Purpose The aim of this study was to evaluate the relationship between abdominal obesity and LVMI, determined as LVM/H2,7, in patients with MS hospitalized due to ACS. Methods 444 consecutive pts were enrolled based on ACS diagnosis. The pts were divided into two groups depending on MS diagnosis: group A – 310 pts with MS and AO (205 M, mean age 63.3 ± 10.5 yrs), group B - 134 pts without MS (101 M, mean age 61,4 ± 12.7 yrs). The group A was divided to two subgroups depending on AO diagnosis: group A1 - 288 pts with MS and AO (185 M, mean age 63.4 ± 10.2 yrs and group A2 - 22 pts with MS without AO (19 M, mean age 62,6 ± 12.7 yrs). In all enrolled pts hypertension was diagnosed. Results A significant difference was found between group A and B with the respect to LVMI (68.4 ± 25.9 vs. 58.3 ± 16.5, p < 0.05). In the group B, a significant association was found between LVMI and waist circumference (r = 0.39, p < 0.05), weight (r = 0.22, p = 0.012), as well as BMI (r = 0.35, p < 0.05). In group A, LVMI was significantly correlated only with weight (r = 0.24, p < 0.05). No significant differences were found between pts with AO and without AO with respect to LVMI (68.9 ± 26.2 vs. 61.4 ± 20.9, p = 0.187). Conclusion 1. In individuals without MS hospitalized due to acute coronary syndrome significant positive correlation was found between LVMI and waist circumference, weight as well as BMI. 2. There is significant difference between pts with MS and without MS with the respect to LVMI. 3. No significant differences were found in LVMI between pts with AO and without AO.