Optimal retrofit and process design of distillation plants for energy saving and process intensification

This work is divided in two principal sections. The first concerns the application of more convenient structures to intensive energy consuming plants built before the energy crisis. Two case studies are considered. The first regards the implementation of a preflash device (drum or column) on a crude distillation unit. The limitations of both apparatuses are considered together with the energy saving realized. Particular emphasis is given to the evaluation of the best structure that matches the scope in the energy plant reduction and the respect of the production specifications. The second case considered regards a light ends distillation plant. Different separation sequences derived from the plant configuration are considered. The possibility to reach a reduction of the energy consumption is considered together with the maximum reusage of the plant apparatus, that allows to minimize the capital cost investment. The total annual cost is associated to the required heat exchanger area for the condensers and the reboilers and to the column section diameter. The best solution, that satisfy the scope of the retrofit work minimizing at the same time the employing of new equipment and the energy consumption, is then identified. In the second section of the work the column sequence design is considered. The starting point was the separation of a four components mixture considered with five different feed compositions. All the possible simple column sequences were first analyzed using different sets of heuristic rules and after with more rigorous evaluation. The different solutions are compared to put in evidence the limitations of the heuristic rules, which anyway remain a good tool for a first screening of the most promising structures. The best distillation sequence for each feed composition case is also considered for the implementation of a divided wall column to perform a three component separation. The resulting “hybrid” sequences are made by a simple column that follows or precedes a divided wall column. This type of column was modeled using the modified Underwood-Fenske-Gilliland method to obtain the first design parameters to be utilized as the input to a more rigorous simulation performed with the Aspen Plus simulation package. The different hybrid configurations are then compared with respect to the best simple column structures from which are derived. In the last part of the work a new method to map the space of distillation columns with less than n-1 columns is proposed. Up to now this configuration space was never predicted in a systematic way and only heuristic rules are available to predict only a few of all the possible configurations. Including more distillation column configurations in the research space increases the possibility to identify the sequence that satisfies the research scope. The generation method is presented for a four components mixture but is absolutely general and can be applied for any number of components

Brewer´s Spent Grain to Bioethanol Through a Hybrid Saccharification and Fermentation Process

Brewer´s spent grain, without being pre-treated, has been investigated for bioethanol production through a Hybrid Saccharification and Fermentation (HSF) process with high solid loading. HSF experiments were performed in a 2 L bioreactor where Cellic ® CTec2 was used to perform the enzymatic hydrolysis, and Saccharomyces Cerevisiae was used for the fermentation. The reaction environment was first set to favour saccharification. Then, after 26 h, the reactor was inoculated with the yeast. The results evidenced the presence of glucose, xylose, and arabinose after the conversion of cellulose and hemicellulose and a rapid depletion of glucose after adding the yeast. The pentoses were also consumed, but with a much slower reaction rate. Almost four hours after adding the yeast, the amount of ethanol had reached a maximum and then began to decrease as microorganisms began to use ethanol as a substrate after glucose depletion. The obtained ethanol yield, evaluated with respect to the theoretical value, was equal to 72%

Brewer's spent grain, coffee grounds, burdock, and willow-four examples of biowaste and biomass valorization through advanced green extraction technologies

This paper explores the transformation of biowastes from food industry and agriculture into high-value products through four examples. The objective is to provide insight into the principles of green transition and a circular economy. The first two case studies focus on the waste generated from the production of widely consumed food items, such as beer and coffee, while the other two examine the potential of underutilized plants, such as burdock and willow, as sources of valuable compounds. Phenolic compounds are the main target in the case of brewer's spent grain, with p-coumaric acid and ferulic acid being the most common. Lipids are a possible target in the case of spent coffee grounds with palmitic (C16:0) and linoleic (C18:2) acid being the major fatty acids among those recovered. In the case of burdock, different targets are reported based on which part of the plant is used. Extracts rich in linoleic and oleic acids are expected from the seeds, while the roots extracts are rich in sugars, phenolic acids such as chlorogenic, caffeic, o-coumaric, syringic, cinnamic, gentisitic, etc. acids, and, interestingly, the high-value compound epicatechin gallate. Willow is well known for being rich in salicin, but picein, (+)-catechin, triandrin, glucose, and fructose are also obtained from the extracts. The study thoroughly analyzes different extraction methods, with a particular emphasis on cutting-edge green technologies. The goal is to promote the sustainable utilization of biowaste and support the green transition to a more environmentally conscious economy.info:eu-repo/semantics/publishedVersio

Cerebrospinal fluid, brain, and spinal cord levels of L-aspartate signal excitatory neurotransmission abnormalities in multiple sclerosis patients and experimental autoimmune encephalomyelitis mouse model

The neuroinflammatory process characterizing multiple sclerosis (MS) is associated with changes in excitatory synaptic transmission and altered central concentrations of the primary excitatory amino acid, L-glutamate (L-Glu). Recent findings report that cerebrospinal fluid (CSF) levels of L-Glu positively correlate with pro-inflammatory cytokines in MS patients. However, to date, there is no evidence about the relationship between the other primary excitatory amino acid, L-aspartate (L-Asp), its derivative D-enantiomer, D-aspartate, and the levels of pro-inflammatory and anti-inflammatory cytokines in the CSF of MS. In the present study, we measured by HPLC the levels of these amino acids in the cortex, hippocampus, cerebellum, and spinal cord of mice affected by experimental autoimmune encephalomyelitis (EAE). Interestingly, in support of glutamatergic neurotransmission abnormalities in neuroinflammatory conditions, we showed reduced L-Asp levels in the cortex and spinal cord of EAE mice and increased D-aspartate/total aspartate ratio within the cerebellum and spinal cord of these animals. Additionally, we found significantly decreased CSF levels of L-Asp in both relapsing-remitting (n = 157) MS (RR-MS) and secondary progressive/primary progressive (n = 22) (SP/PP-MS) patients, compared to control subjects with other neurological diseases (n = 40). Importantly, in RR-MS patients, L-Asp levels were correlated with the CSF concentrations of the inflammatory biomarkers G-CSF, IL-1ra, MIP-1β, and Eotaxin, indicating that the central content of this excitatory amino acid, as previously reported for L-Glu, reflects a neuroinflammatory environment in MS. In keeping with this, we revealed that CSF L-Asp levels were positively correlated with those of L-Glu, highlighting the convergent variation of these two excitatory amino acids under inflammatory synaptopathy occurring in MS

Characteristics and patterns of care of endometrial cancer before and during COVID-19 pandemic

Objective: Coronavirus disease 2019 (COVID-19) outbreak has correlated with the disruption of screening activities and diagnostic assessments. Endometrial cancer (EC) is one of the most common gynecological malignancies and it is often detected at an early stage, because it frequently produces symptoms. Here, we aim to investigate the impact of COVID-19 outbreak on patterns of presentation and treatment of EC patients. Methods: This is a retrospective study involving 54 centers in Italy. We evaluated patterns of presentation and treatment of EC patients before (period 1: March 1, 2019 to February 29, 2020) and during (period 2: April 1, 2020 to March 31, 2021) the COVID-19 outbreak. Results: Medical records of 5,164 EC patients have been retrieved: 2,718 and 2,446 women treated in period 1 and period 2, respectively. Surgery was the mainstay of treatment in both periods (p=0.356). Nodal assessment was omitted in 689 (27.3%) and 484 (21.2%) patients treated in period 1 and 2, respectively (p<0.001). While, the prevalence of patients undergoing sentinel node mapping (with or without backup lymphadenectomy) has increased during the COVID-19 pandemic (46.7% in period 1 vs. 52.8% in period 2; p<0.001). Overall, 1,280 (50.4%) and 1,021 (44.7%) patients had no adjuvant therapy in period 1 and 2, respectively (p<0.001). Adjuvant therapy use has increased during COVID-19 pandemic (p<0.001). Conclusion: Our data suggest that the COVID-19 pandemic had a significant impact on the characteristics and patterns of care of EC patients. These findings highlight the need to implement healthcare services during the pandemic

Practice patterns and 90-day treatment-related morbidity in early-stage cervical cancer

To evaluate the impact of the Laparoscopic Approach to Cervical Cancer (LACC) Trial on patterns of care and surgery-related morbidity in early-stage cervical cancer

Novel Intensified Alternatives for Purification of Levulinic Acid Recovered from Lignocellulosic Biomass

The development of a bio-based economy has its foundations in the development of efficient processes to optimize biomass potential. In this context there are a multitude of molecules that can be either synthetized or recovered from biomass, among those the so-called 12 building-blocks reported by the US Department of Energy. Even if their identification and importance is clearly defined, research efforts concerning the purification or separation of these platform molecules are limited. To fill this gap, different configurations for the purification of levulinic acid recovered from lignocellulosic biomass are examined and compared in this work. In particular, hybrid configurations obtained by the combination of liquid-liquid extraction and distillation have been considered. It was demonstrated how a deep understanding of the subspace including all extraction-assisted simple column distillation configurations represents a fundamental step in the synthesis of different process alternatives. From a separation efficiency and economic standpoint, the proposed intensified liquid-liquid thermally equivalent configuration (LL-TE) and liquid-liquid side stream column configuration (LL-SSC) are promising solutions. Nonetheless, their performances are deeply interrelated to the purity target defined by the designer