scholarly journals Efficiency of the process of cryogenic air separation into the components

2009 ◽  
Vol 63 (5) ◽  
pp. 397-405 ◽  
Author(s):  
Milance Mitovski ◽  
Aleksandra Mitovski

The separation process of atmospheric air into its components by means of cryogenic low-pressure procedure, which takes place in the Oxygen plant in the Copper Mining and Smelting Complex, yields various products of different quantities and purities. Proper assessment of the energy consumption, hence assignments production cost of individual products may present considerable problem. For that goal, the least invested technical operation was adopted as criteria, and was restrained for all costs of production and distribution of specific energy. Case study was carried out in the Oxygen factory by monitoring producing parameters for the process in the 2007 year. Based on the monitoring of production parameters and their costs for 20 months in the period 2004-2005, correlation equations for power consumption in the total monthly amount and per mass of produced gaseous oxygen were created. The energy and exergy efficiency of the air separation process into the components are expressed as the ratio of input and useful energy and exergy of the process. On the basis of the adopted criteria, the assignments of energy consumption and production costs for cryogenic air separation process into the components are as follows: 82.59% for gaseous oxygen, 14.04% for liquid oxygen, 1.39% for gaseous nitrogen and 1.98% for liquefied nitrogen. The air separation efficiency is achieved in the amount of energy 0.0872-0.1179 and exergy 0.0537-0.1247. Power consumption per mass of the products in 2007 year is 1325.059 kWh/t of liquid oxygen, 828.765 kWh/t of liquid nitrogen, 429.812 kWh/t of gaseous oxygen and 309.424 kWh/t of nitrogen gas. Production costs of the technical gases at the dawn of the factory are: 6730.69 RSD/t of liquid oxygen, 4209.74 RSD/t of liquid nitrogen, 2183.25 RSD/t of gaseous oxygen and 1571.73 RSD/t of gaseous nitrogen.

2014 ◽  
Vol 881-883 ◽  
pp. 653-658 ◽  
Author(s):  
Yong Qiang Xiong ◽  
Ben Hua

In this paper, a cryogenic air separation process with LNG cold energy utilization is proposed to produce liquid nitrogen and high pressure pure oxygen gas economically. To reduce the electric energy consumption of air separation products, liquid nitrogen have been produced by condensing the separated pure nitrogen gas with LNG cold energy utilization, and the recycled nitrogen is served to transfer cold energy from LNG stream to cool off air stream in the proposed cryogenic air separation process. The specifications of streams and the major equipments of the air separation process are simulated with Aspen Plus software and the main parameters analysis are performed. The results show that the energy consumption of the proposed air separation process with LNG cold energy utilization decreased about 58.2% compared with a conventional cryogenic air separation process. The compressed pressure of recycled nitrogen has a big impact on the cost of air separation products and utilization efficiency of LNG cold energy. The LNG cold energy could be fully utilized when the recycled nitrogen has been compressed to above 6.5MPa.


2016 ◽  
Author(s):  
S. Tesch ◽  
T. Morosuk ◽  
G. Tsatsaronis

The increasing demand for primary energy leads to a growing market of natural gas and the associated market for liquefied natural gas (LNG) increases, too. The liquefaction of natural gas is an energy- and cost-intensive process. After exploration, natural gas, is pretreated and cooled to the liquefaction temperature of around −160°C. In this paper, a novel concept for the integration of the liquefaction of natural gas into an air separation process is introduced. The system is evaluated from the energetic and exergetic points of view. Additionally, an advanced exergy analysis is conducted. The analysis of the concepts shows the effect of important parameters regarding the maximum amount of liquefiable of natural gas and the total power consumption. Comparing the different cases, the amount of LNG production could be increased by two thirds, while the power consumption is doubled. The results of the exergy analysis show, that the introduction of the liquefaction of natural gas has a positive effect on the exergetic efficiency of a convetional air separation unit, which increases from 38% to 49%.


2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Suksun Amornraksa ◽  
Ittipat Subsaipin ◽  
Lida Simasatitkul ◽  
Suttichai Assabumrungrat

Abstract Separation process is very crucial in bioethanol production as it consumes the highest energy in the process. Unlike other works, this research systematically designed a suitable separation process for bioethanol production from corn stover by using thermodynamic insight. Two separation processes, i.e., extractive distillation (case 2) and pervaporation (case 3), were developed and compared with conventional molecular sieve (case 1). Process design and simulation were done by using Aspen Plus program. The process evaluation was done not only in terms of energy consumption and process economics but also in terms of environmental impacts. It was revealed that pervaporation is the best process in all aspects. Its energy consumption and carbon footprint are 60.8 and 68.34% lower than case 1, respectively. Its capital and production costs are also the lowest, 37.0 and 9.88% lower than case 1.


Author(s):  
T. Morosuk ◽  
M. Schult ◽  
G. Tsatsaronis

The liquefied natural gas (LNG) market has grown significantly and the growth is expected to continue in the future. New technologies that lead to an increased efficiency in each step of the LNG chain are currently under consideration. The studies and the commercial applications associated with the LNG regasification processes can be divided into three large groups: (a) Direct and indirect heat transfer processes between water and LNG; (b) LNG-based co-generation systems, and (c) industrial complexes consisting of an LNG import terminal and an energy-conversion plant, or an energy-intensive chemical plant. In this paper a novel concept for integrating the LNG vaporization into an air separation process is presented. The simulation, energy and exergy analyses are discussed.


2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Zeinab A. M. Khalel ◽  
Ali A. Rabah ◽  
Taj Alasfia M. Barakat

A new cryogenic air separation process with flash separator is developed. A flash separator is added to the conventional double-column cryogenic air separation process. The flash separator is used to replace the turbine required to recover a portion of the energy in the double-column air separation process. The flash separator served dual purposes of throttling and separation. Both the conventional and the new processes are simulated using Aspen Plus version 11.1 the model air flow rate and compositions are taken as 50000 Nm3/h of air at standard conditions of 1 atm and 25°C and feed composition of 79.1% N2 and 20.9% O2. The new process decreases the energy consumption and increases the productivity.


2014 ◽  
Vol 1033-1034 ◽  
pp. 146-150 ◽  
Author(s):  
Yong Qiang Xiong ◽  
Peng Luo ◽  
Ben Hua

Oxy-fuel combustion is a leading potential technology to capture CO2. Because the oxygen production process is causing the largest power penalty in oxy-fuel combustion system, it is essential to cut down oxygen separation power penalty for capturing CO2 at low cost. This paper presents the energy consumption analysis results of air separation units with three different cycles offering for oxy-fuel combustion systems. The study shows that when the gaseous oxygen compression (GOXC) cycle is selected for pressuring oxygen product stream, the specific consumption of high pressure and low purity oxygen with triple column cycle is about 6.4-7.2% less than that of with dual column cycle. And when choosing triple column cycle for oxygen production, an air separation unit with pumped liquid oxygen (PLOX) cycle is a better option than with GOXC cycle because it helps to improve plant safety and to decrease energy consumption of high pressure oxygen products.


1994 ◽  
Author(s):  
GARY GENGE ◽  
MARSHALL SAVILLE ◽  
ALSON GU

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