Critical analysis of process integration options for joule-cycle and conventional heat pumps

To date, research on heat pumps (HP) has mainly focused on vapour compression heat pumps (VCHP), transcritical heat pumps (TCHP), absorption heat pumps, and their heat integration with processes. Few studies have considered the Joule cycle heat pump (JCHP), which raises several questions. What are the characteristics and specifics of these different heat pumps? How are they different when they integrate with the processes? For different processes, which heat pump is more appropriate? To address these questions, the performance and integration of different types of heat pumps with various processes have been studied through Pinch Methodology. The results show that different heat pumps have their own optimal application range. The new JCHP is suitable for processes in which the temperature changes of source and sink are both massive. The VCHP is more suitable for the source and sink temperatures, which are near-constant. The TCHP is more suitable for sources with small temperature changes and sinks with large temperature changes. This study develops an approach that provides guidance for the selection of heat pumps by applying Process Integration to various combinations of heat pump types and processes. It is shown that the correct choice of heat pump type for each application is of utmost importance, as the Coefficient of Performance can be improved by up to an order of magnitude. By recovering and upgrading process waste heat, heat pumps can save 15-78% of the hot utility depending on the specific process

Regional power plan assessment accounting for environmental footprints

Enabling a higher share of renewables in power planning at the municipal and regional scale is essential for offering local communities a path to sustainable development. However, the utilisation of renewables also carries certain environmental burdens which have to be accounted for in the process of system design and planning. The current paper takes this issue as a departure point, adding the electrical energy storage as a degree of freedom and its influence on the environmental footprints - represented by Greenhouse Gas and Water Footprints. The proposed model and the illustration case study clearly demonstrate the strong dependence of the footprints on the size of the storage facility. Future work should extend the model to account for all essential problem features - including a longer planning horizon, additional footprints and their interrelationships, as well as the interaction with the economic performance of the system

Optimization Design and Performance Study of a Heat Exchanger for an Oil and Gas Recovery System in an Oil Depot

High summer temperatures pose numerous challenges to the oil and gas recovery process in oil depots, including reduced adsorption tank recovery rates and decreased absorption tower desorption efficiency. This paper introduces a coupling design approach that integrates chemical process design with computational fluid dynamics simulation. The proposed approach is then utilized to investigate the optimal design and performance of the heat exchanger within the oil depot’s oil and gas recovery system. First, according to the given process design parameters, the heat exchanger is preliminary designed to determine the required heat exchange area and heat load. Based on the preliminary design results, a detailed design is carried out, resulting in the following calculations: the hot fluid has inlet and outlet temperatures of 40 °C and 29.52 °C, respectively, with an outlet flow velocity of 9.89 m/s. The cold fluid exhibits inlet and outlet temperatures of 25 °C and 26.98 °C, respectively, with an outlet flow velocity of 0.06 m/s. The specific structure and dimensions of the heat exchanger are determined, including the shell type, pipe specifications, and pipe length. Finally, CFD numerical simulation is utilized to analyze the flow field, velocity field, and pressure field within the designed heat exchanger. The calculations reveal the following findings: the hot fluid exhibited inlet and outlet temperatures of 40 °C and 29.54 °C, respectively, along with an outlet flow velocity of 9.94 m/s. On the other hand, the cold fluid shows inlet and outlet temperatures of 25 °C and 26.39 °C, respectively, with an outlet flow velocity of 0.061 m/s. The results show that the chemical process design and CFD numerical simulation results are consistent and can be mutually verified. The designed heat exchanger can efficiently cool oil and gas from 40 °C to 30 °C, and the oil and gas processing capacity can reach 870 m3/h, which is conducive to realizing the goals of energy saving, environmental protection, and safety

Development of a Check-All-That-Apply (CATA) Ballot and Machine Learning for Generation Z Consumers for Innovative Traditional Food

Generation Z (Gen Z) consumers account for an increasing proportion of the food market. The aim of this study took lamb shashliks as an example and developed novel products from the perspective of cooking methods in order to develop a traditional food suitable for Gen Z consumers. The sensory characterization of electric heating air (EH), microwave heating (MH), air frying (AF), and control (traditional burning charcoal (BC) of lamb shashliks) was performed using the CATA methodology with 120 Gen Z consumers as assessors. A 9-point hedonic scale was used to evaluate Gen Z consumers’ preferences for the cooking method, as well as a CATA ballot with 46 attributes which described the sensory characteristics of lamb shashliks. The machine learning algorithms were used to identify consumer preferences for different cooking methods of lamb shashliks as a function of sensory attributes and assessed the relationship between products and attributes present in the perceptual map for the degree of association. Meanwhile, sensory attributes as important variables play a relatively more important role in each cooking method. The most important variables for sensory attributes of lamb shashliks using BC are char-grilled aroma and smoky flavor. Similarly, the most important variables for AF samples are butter aroma, intensity aroma, and intensity aftertaste, the most important variables for EH samples are dry texture and hard texture, and the most important variables for MH samples are light color regarding external appearance and lumpy on chewing texture. The interviews were conducted with Gen Z consumers to investigate why they prefer innovative products—AF. Grounded theory and the social network analysis (SNA) method were utilized to explore why consumers chose AF, demonstrating that Gen Z consumers who had previously tasted AF lamb shashliks could easily perceive the buttery aroma. This study provides a theoretical and practical basis for developing lamb shashliks tailored to Gen Z consumers

Molecular cloning, genomic organization and functional analysis of an anti-lipopolysaccharide factor from Chinese mitten crab Eriocheir sinensis

Anti-lipopolysaccharide factor (ALF) represents one kind of basic proteins, which binds and neutralizes LPS and exhibits strong antibacterial activity against Gram-negative R-type bacteria. The ALF gene of Chinese mitten crab Eriocheir sinensis (Milne Edwards, 1853) (denoted as EsALF) was identified from haemocytes by expressed sequence tag (EST) and PCR approaches. The full-length cDNA of EsALF consisted of 700 nucleotides with a canonical polyadenylation signal-sequence AATAAA, a polyA tail, and an open-reading frame of 363 bp encoding 120 amino acids. The high similarity of EsALF-deduced amino acid sequence shared with the ALFs from other species indicated that EsALF should be a member of ALF family. The mRNA expression of EsALF in the tissues of heart, gonad, gill, haemocytes, eyestalk and muscle was examined by Northern blot analysis and mRNA transcripts of EsALF were mainly detected in haemocytes, heart and gonad. The temporal expression of EsALF in haemocytes after Vibrio anguillarum challenge was recorded by quantitative real-time RT-PCR. The relative expression level of EsALF was up-regulated rapidly at 2 h post-injection and reached 3-fold to that in blank group. After a drastic decrease to the original level from 4 to 8h, the expression level increased again and reached 4-fold to that in the blank group at 12 h post-injection. The genomic DNA sequence of EsALF gene consists of 1174bp containing three exons and two introns. The coding sequence of the EsALF mature peptide was cloned and expressed in Escherichia coli BL21(DE3)-pLysS to further elucidate its biological functions. The purified recombinant product showed bactericidal activity against both Gram-positive (G(+)) and Gram-negative (G(-)) bacteria, which demonstrated that the rEsALF was a broad-spectrum antibacterial peptide. All these results indicated that EsALF was an acute-phase protein involved in the immune responses of Chinese mitten crab, and provided a potential therapeutic agent for disease control in aquaculture. (c) 2007 Elsevier Ltd. All rights reserved

Effects of Feedstock and Pyrolysis Temperature on Biochar Adsorption of Ammonium and Nitrate

<div><p>Biochar produced by pyrolysis of biomass can be used to counter nitrogen (N) pollution. The present study investigated the effects of feedstock and temperature on characteristics of biochars and their adsorption ability for ammonium N (NH₄⁺-N) and nitrate N (NO₃⁻-N). Twelve biochars were produced from wheat-straw (W-BC), corn-straw (C-BC) and peanut-shell (P-BC) at pyrolysis temperatures of 400, 500, 600 and 700°C. Biochar physical and chemical properties were determined and the biochars were used for N sorption experiments. The results showed that biochar yield and contents of N, hydrogen and oxygen decreased as pyrolysis temperature increased from 400°C to 700°C, whereas contents of ash, pH and carbon increased with greater pyrolysis temperature. All biochars could sorb substantial amounts of NH₄⁺-N, and the sorption characteristics were well fitted to the Freundlich isotherm model. The ability of biochars to adsorb NH₄⁺-N followed: C-BC>P-BC>W-BC, and the adsorption amount decreased with higher pyrolysis temperature. The ability of C-BC to sorb NH₄⁺-N was the highest because it had the largest cation exchange capacity (CEC) among all biochars (e.g., C-BC400 with a CEC of 38.3 cmol kg⁻¹ adsorbed 2.3 mg NH₄⁺-N g⁻¹ in solutions with 50 mg NH₄⁺ L⁻¹). Compared with NH₄⁺-N, none of NO₃⁻-N was adsorbed to biochars at different NO₃⁻ concentrations. Instead, some NO₃⁻-N was even released from the biochar materials. We conclude that biochars can be used under conditions where NH₄⁺-N (or NH₃) pollution is a concern, but further research is needed in terms of applying biochars to reduce NO₃⁻-N pollution.</p></div