scholarly journals Evaluación de la producción de aceite crudo de palma y palmiste en el norte de Colombia mediante el análisis de exergía asistido por computador

Author(s):  
Kariana Moreno Sader ◽  
Jeffrey León Pulido ◽  
Ángel González-Delgado

Palm production chains in Colombia have some unsatisfied demands that affect their competitiveness. Specific demands include efficiency in energy use. Therefore, in the present report, an exergy analysis for the dual crude palm and kernel oil production process was carried out to determine the main energy sinks and suggest technological improvements that allow better use of energy. For this study, the process was initially simulated in the Aspen Plus ® software, where the chemical and physical exergies of the species and streams involved were quantified. The process irreversibilities, the exergy loss, the exergy of waste, and the exergy of utilities were calculated for each stage and the whole process. An overall exergy efficiency of 18% was achieved, while the highest process irreversibilities contribution was due to the destroyed exergy with the waste in the threshing stage. To increasing the global exergy efficiency of dual crude palm and kernel oil production, it is proposed the evaluation of palm rachis use to obtain biofuels and/or high-value products.

Author(s):  
Hammed Adeniyi Salami

A comparative assessment of environmental impacts associated with the energy use in palm kernel oil production and cashew nut processing industries was carried out using life cycle assessment. One Kg of products from both industries was chosen as the functional unit. The gate – to – gate life cycle assessment results indicated that the total contribution per functional unit to global warming potential (GWP), abiotic depletion potential (ADP) and acidification potential (AP) were 50.2809 g of CO2 equivalents, 0.1524 g antimony equivalents and 0.1280 g of SO2 equivalents respectively for palm kernel oil production and 39.8350 g of CO2 equivalents, 0.1209 g antimony equivalents and 0.0957 g of SO2 equivalents respectively for cashew nut processing. The scenario-based results indicated substantial reductions for all the considered impact  categories; approximately 18, 28 and 94% reductions were achieved for ADP, GWP and AP respectively for both industries when public power supply from the natural grid was the main energy source for agricultural production. Increasing the thermal efficiency of the    nation’s existing power architecture resulted into 62 and 56% reductions for GWP and ADP respectively for the two industries, while additional 6 and 7% reductions were achieved for both impact categories when the transmission and distribution loss was maintained at 5%. The widespread adoption of clean and renewable energy sources, instead of over-reliance on electricity supply from the diesel-powered generator, has been identified as a feasible alternative towards achieving sustainability in the agro-processing industry.


Author(s):  
Shimin Deng ◽  
Rory Hynes

In this paper, SNG production technologies are investigated and summarized. A new SNG production process has been developed. It has advantages in performance, cost and operability. The performance of the new process is analyzed and compared with two existing processes — one process based on hydrogasification and one conventional SNG production process. Based on process modeling, exergy analysis is carried out to identify the specific loss of each sub-process. The thermodynamic features of the new process are investigated to show the trend of the parameters of the hybrid gasifier and the whole process. A concept of critical conversion rate is identified and defined. Key parameters of hybrid gasifier and thermal performance of the system are examined and presented. Besides thermal performance, other issues related to operation and cost are discussed.


Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1152
Author(s):  
Le Cao Nhien ◽  
Nguyen Van Duc Long ◽  
Moonyong Lee

Furfural is only derived from lignocellulosic biomass and is an important chemical used in the plastics, agrochemical, and pharmaceutical industries. The existing industrial furfural production process, involving reaction and purification steps, suffers from a low yield and intensive energy use. Hence, major improvements are needed to sustainably upgrade the furfural production process. In this study, the conventional furfural process based on a continuous stirred tank reactor and distillation columns was designed and optimized from an actual aqueous xylose solution via a biomass pretreatment step. Subsequently, a reactive distillation (RD) and extraction/distillation (ED) configuration was proposed for the reaction and purification steps, respectively, to improve the process efficiency. RD can remove furfural instantly from the reactive liquid phase and can separate heavy components from the raw furfural stream, while the ED configuration with toluene and butyl chloride used as extracting solvents can effectively separate furfural from a dilute aqueous stream. The results showed that the hybrid RD-ED process using a butyl chloride solvent saves up to 51.8% and 57.4% of the total investment costs and total annual costs, respectively, compared to the conventional process. Furthermore, environmental impacts were evaluated and compared for all structural alternatives.


1996 ◽  
Vol 118 (2) ◽  
pp. 81-88 ◽  
Author(s):  
G. Bisio

Energy storage is a key technology for many purposes and in particular for air conditioning plants and a successful exploitation of solar energy. Thermal storage devices are usually classified as either variable temperature (“sensible heat”) or constant temperature (“latent heat”) devices. For both models a basic question is to determine the efficiency suitably: Only exergy efficiency appears a proper way. The aim of this paper is to examine exergy efficiency in both variable and constant temperature systems. From a general statement of exergy efficiency by the present author, two types of actual definitions are proposed, depending on the fact that the exergy of the fluid leaving the thermal storage during the charge phase can be either totally lost or utilized elsewhere. In addition, specific remarks are made about the exergy of a system in a periodically varying temperature environment.


2013 ◽  
Vol 732-733 ◽  
pp. 52-56
Author(s):  
Zhi Guo Wang ◽  
Lei Zhang ◽  
Chai Ling Yin

Cryogenic separation method is the main method to recycle NGL (Natural Gas Liquid). Oilfield two-stage expansion NGL cryogenic separation plant is a complex system composed of varieties of material flow, energy flow and equipments, is a typical distributed energy use system composed of three parts, energy supply, energy use and waste heat recovery. In this paper, according to the process characteristics of two-stage expansion cryogenic separation plant, three-box analysis method was used, the system was compartmentalized into six subsystems, represented the exergy analysis model of system—unit—equipment, given the specific analysis process and the assessment rules for the NGL system. Using the practical operational data, the writers conduct the exergy analysis on the operational working condition of Daqing oilfield NGL system. Based on the calculation results, this paper raises some proposals to improve the operational efficiency, and achieved a good energy saving effect in engineering practice.


2003 ◽  
Vol 125 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Afif Akel Hasan ◽  
D. Y. Goswami

Exergy thermodynamics is employed to analyze a binary ammonia water mixture thermodynamic cycle that produces both power and refrigeration. The analysis includes exergy destruction for each component in the cycle as well as the first law and exergy efficiencies of the cycle. The optimum operating conditions are established by maximizing the cycle exergy efficiency for the case of a solar heat source. Performance of the cycle over a range of heat source temperatures of 320–460°K was investigated. It is found that increasing the heat source temperature does not necessarily produce higher exergy efficiency, as is the case for first law efficiency. The largest exergy destruction occurs in the absorber, while little exergy destruction takes place in the boiler.


2022 ◽  
Vol 226 ◽  
pp. 107070
Author(s):  
Shuo Ma ◽  
Shilei Lu ◽  
Hongting Ma ◽  
Renxi Li ◽  
Chang Xu ◽  
...  

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 446 ◽  
Author(s):  
Lei Zhang ◽  
Nasir Khan ◽  
Chunsheng Pu

Due to the strong heterogeneity between the fracture and the matrix in fractured oil reservoirs, injected water is mainly moved forward along the fracture, which results in poor water flooding. Therefore, it is necessary to reduce the water cut and increase oil production by using the conformance control technology. So far, gel particles and partially hydrolyzed polyacrylamide (HPAM)/Cr3+ gel are the most common applications due to their better suitability and low price. However, either of the two alone can only reduce the conductivity of the fracture to a certain extent, which leads to a poor effect. Therefore, to efficiently plug the fracture to enhance oil recovery, a combination of gel particles and the HPAM/Cr3+ system is used by laboratory tests according to their respective advantages. The first step is that the gel particles can compactly and uniformly cover the entire fracture and then the fracture channel is transformed into the gel particles media. This process can enhance the oil recovery to 18.5%. The second step is that a suitable HPAM/Cr3+ system based on the permeability of the gel particles media is injected in the fractured core. Thus, the fracture can be completely plugged and the oil in the matrix of the fractured core can be displaced by water flooding. This process can enhance oil recovery to 10.5%. During the whole process, the oil recovery is increased to 29% by this method. The results show that this principle can provide a new method for the sustainable and efficient development of fractured oil reservoirs.


Pomorstvo ◽  
2019 ◽  
Vol 33 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Ivan Lorencin ◽  
Nikola Anđelić ◽  
Vedran Mrzljak ◽  
Zlatan Car

The paper presents an exergy analysis of marine steam turbine labyrinth (gland) seals - an inevitable component of any marine steam turbine cylinder, in three different operating regimes. Throughout labyrinth seals, steam specific enthalpy can be considered as a constant because the results obtained by this assumption do not deviate significantly from the results of complex numerical models. Changes in labyrinth seals exergy efficiency and specific exergy destruction are reverse proportional. The analyzed labyrinth seals have high exergy efficiencies in each observed operating regime at the ambient temperature of 298 K (above 92%), what indicates seals proper operation. An increase in the ambient temperature resulted with a decrease in labyrinth seals exergy efficiency, but even at the highest observed ambient temperature of 318 K, seals exergy efficiency did not fall below 90.5% in each observed operating regime.


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