Strip Temperature Research Articles

The Impact of the Gas Inlet Position, Flow Rate, and Strip Velocity on the Temperature Distribution of a Stainless-Steel Strips during the Hardening Process

A non-uniform temperature across the width of martensitic stainless-steel strips is considered to be one of the main reasons why the strip exhibits un-flatness defects during the hardening process. Therefore, the effect of the gas inlet position in this process, on the temperature distribution of the steel strip was investigated numerically. Furthermore, an infrared thermal imaging camera was used to compare the model predictions and the actual process data. The results showed that the temperature difference across the width of the strip decreased by 9% and 14% relative to the calculated temperature and measured values, respectively, when the gas inlet position was changed. This temperature investigation was performed at a position about 63 mm from the bath interface. Moreover, a more symmetrical temperature distribution was observed across the width of the strip. In addition, this study showed that by increasing the amount of the hydrogen flow rate by 2 Nm3/h, a 20% reduction of temperature difference across the width of strip was predicted. Meanwhile, the results show that the effect of the strip velocity on the strip temperature is very small.

Interfacial properties of p53-DNA complexes containing various recognition elements

Methods which can distinguish between specific and non-specific protein interactions leading to the identification of hubs and nodes are still desired. This work shows utilization of chronopotentiometric stripping analysis in combination with a mercury electrode in the study of protein-DNA interactions at thiol-modified electrodes. The complex of tumor suppressor p53 core domain (p53CD) and DNA undergoes disintegration due to the effect of the electric field, accompanied by a remarkable increase in the electrocatalytic reduction signal. By adjusting stripping current intensities and temperature, the transition between intact and disintegrated complex reflected differences in the stabilities of sequence-specific complexes with different recognition elements. Higher stabilities of p53-DNA complexes were observed for DNA binding sites connected with cell-cycle arrest and p53 negative autoregulation, than those for DNA associated with cell apoptosis, in good concordance with electrophoretic mobility shift assay in polyacrylamide gels. These data highlight the utility of this method for studying the dynamics of surface-attached protein-DNA complexes.

Partial oxy-combustion technology for energy efficient CO2 capture process

Partial oxy-combustion is considered a promising carbon capture and storage technology that can lead to further energy penalty reductions. The presence of large amounts of CO2 in the flue gas should enhance the driven force in the bulk gas and hence the absorption performance. A novel concept known as Shift to Low Temperature configuration has been developed in order to strengthen the potentialities of partial oxy-combustion. This novel configuration aims at relaxing the operating conditions in the stripper based on the benefits – kinetics and driven force – observed in the absorption unit by means of shifting the operational CO2 cyclic capacity of the solvents towards lower energy requirements for solvent regeneration. In this work, three partial oxy-combustion operating conditions were tested in an experimental bench-scale CO2 capture facility. Results from the test campaign were further compared with both post-combustion and partial oxy-combustion at conventional operating conditions. The energy requirements were further improved as this novel configuration was applied, particularly using 118 °C as stripping temperature in combination with 60%v/v CO2 in the flue gas. Under these operating conditions, the energy penalty was reduced by 11% with respect to conventional partial oxy-combustion operation using the same flue gas composition – from 4.55 to 4.05 GJ/t CO2 using MEA 30 wt% as solvent. The energy penalty was further decreased by up to 64% in comparison with the post-combustion test. The results endorse the use of large CO2 cyclic capacity solvents to enhance the potentialities of the Shift to Low Temperature configuration for carbon capture applications.

A comprehensive mathematical model for an accurate calculation of the oil film thickness of strip cold rolling

The surface quality of cold rolled strip is related to a greater extent on the rolling oil film thickness, and there are many factors that affect the oil film thickness. Considering the various factors comprehensively, an integrated mathematical model is established, such as roughness of rolls and strips, elastohydrodynamic lubrication, friction heat and plastic deformation heat in the rolling zone, viscosity varying with temperature and pressure, etc. A series of equations are developed, such as the Reynolds equation of partial membrane hydrodynamic lubrication based on average flow theory, equation of oil film thickness on rough elastic surface, the thermal interface equations between strip, oil film and roller surface, surface asperity contact pressure equation, lubricant viscosity and density equations, motion equation of the oil film, etc. This model is solved by finite difference method to get the film pressure, oil film thickness, and temperature distribution in the rolling zone. The average rolling pressure, the roll, and strip temperature calculated by the model are very close to the field test results. Comparing the minimum film thickness calculated by the model with the regression formula of other literature test, the error is less than 10%. The minimum oil film thickness is analyzed. It increases with the decrease of the rolling force and is approximately proportional to the rolling speed and lubricant viscosity.

An investigation of the Temperature Distribution of a Thin Steel Strip during the Quenching Step of a Hardening Process

The dimension quality of the strip within the hardening process is an essential parameter, which great attention needs to be paid. The flatness of the final product is influenced by the temperature distribution of the strip, specifically across the width direction. Therefore, based on physical theories, a numerical model was established. The temperature of the strip for the section before the martensitic transformation was objected in the predicted model by using a steady state approach. In addition an infrared thermal imaging camera was applied in the real process in order to validate the results and to improve the boundary conditions of the numerical model. The results revealed that the temperature of strip decreased up to 250 °C within the area between the furnace and the quenching bath. This, in turn, resulted in significant temperature difference across the width of the strip. This difference can be up to 69 °C and 41 °C according to the numerical results and thermal imaging data, respectively. Overall, this study gave a better insight into the cooling step in the hardening process. In addition, this investigation can be used to improve the hardening process as well as an input for future thermal stress investigations.

The consequences of eliminating the soaking section of a commercial hot-dip galvanising line for HSLA production and a control strategy for improving product consistency

ABSTRACT This paper describes the results of the investigations done to adapt the thermal cycles applied to High Strength Low Alloy (HSLA) steels to the new furnace configuration of a galvanizing line. During the revamping of a hot dip galvanizing line, new radiant tubes were installed in the soaking furnace with the purpose of increasing the line capacity. This modification eliminated the soaking stage and forced to redesign the thermal cycles of the furnace. As the classical cycles proposed for the HSLAs worrisomely increased the percentage of rejections, it was defined a new control parameter based on the strip thickness, time in the furnace and strip temperature to guarantee the mechanical characteristics of these steels.

Removal of ammonia from a smelting wastewater by cyclic stripping and acid adsorption: Kinetics study

Air stripping is an effective method for the removal of ammonia from high‐concentration wastewater. The traditional open stripping process is expensive due to high consumptions of alkali reagent and energy. This study proposed a novel cyclic stripping‐acid adsorption system for ammonia removal. The stripped ammonia gas flowed into the stripping tower, and no fresh air was added during the cyclic stripping process. The kinetics model of ammonia removal from the smelting wastewater in a pilot‐scale cyclic stripping tower was investigated. The influences of stripping temperature (T), wastewater pH, air to liquid ratio (R), and acid spray flow (F) on the ammonia removal rate were discussed. The kinetics equation was determined as G = 4.14 × 10−3 × pH1.83 × T0.27 × F0.98 × R−0.49 when pH = 9.80–12.29, T = 19–35°C, F = 58–76 m3·h−1, and R = 1329–1725. The equation can be used to predict the removal rate of ammonia during operation. The ammonia concentration of the effluent decreased from 5951 mg·L−1 to 13 mg·L−1 within 15 h. Ammonia can be removed rapidly and economically from wastewater via the cyclic stripping process. © 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019

Numerical Simulation of Cast-rolling Process for Copper-Aluminum Composite Plate

Taking horizontal twin-roll casting mill as the research object, the geometric modeling and gridding of the rolling mill are completed by using the design modeler and gridding module of ANSYS Wrkbench platform. Combined with Fluent fluid simulation module, a two-dimensional steady-state laminar flow coupled model of copper-aluminium clad plate cast-rolling process was established. Through the analysis of range data obtained by orthogonal simulation design method, the order of importance of each factor is as follows: billet speed, cast-rolling zone length, preheating temperature of copper strip, pouring temperature. Through the analysis of factors and indicators (liquid hole depth ratio), the suitable technological parameters range are 0.3~0.6 m.min-1 for billet speed, 933~993 K for pouring temperature, 300~431 K for preheating temperature of copper strip, 57~80 mm for cast-rolling zone length. In order to verify the reliability of numerical simulation method and result analysis, the casting-rolling test was carried out with simulated process parameters. The exit temperature was measured by thermocouple. The results show that the error between simulation results and measured results is small, which verifies the accuracy of simulation and the feasibility of guiding production. When the billet speed is 0.5 m/min, the pouring temperature is 963 K, the length of casting-rolling zone is 70 mm and the copper strip is not preheated, the 10 mm thick copper-aluminium composite plate has better shape. The tensile properties show that the composite plate has both the high plasticity of aluminium and the high strength of copper.

Effect of Base Strip Temperature on Bonding of Three-Layer Clad Strip Cast by a Vertical-Type Tandem Twin Roll Caster

The effect of the base strip temperature on the bonding between base strip and overlay strips in a three-layer clad strip cast by a vertical-type tandem twin roll caster was investigated. The base strip was 3003 aluminum alloy and the overlay strip was 4045 aluminum alloy. The bonding was investigated for base strip temperatures ranging from 200 °C to 550 °C. The bonding condition was investigated by cold-rolling, bending-to-failure test and tensile shear test. The shear stress increased with the base strip temperature. Sound bonding was achieved at base strip temperatures higher than 450 °C. The results of this study indicated that the second caster is not required to be set below the first roll caster.

Investigation of Energy-Saving Designs for an Aqueous Ammonia-Based Carbon Capture Process

In an aqueous ammonia-based postcombustion carbon capture (PCC) process, the regeneration energy of the CO2 lean solvent dominates the overall energy consumption. The energy reduction in the CO2 stripper can be achieved by either formulating new solvents or optimizing the process configurations. The ammonia concentration in the lean solvent is an important design parameter. A high concentration of ammonia results in a lesser lean solvent required at a constant CO2 removal efficiency, e.g., 90%; however, it encourages the formation of ammonium bicarbonate in the reflux, which brings the desorbed CO2 back into the stripper. To achieve constant CO2 removal, extra solvent in the stripper needs to be vaporized, which results in higher energy consumption than that required in applying a lean solvent with a low ammonia concentration. In this study, an index, which is the vaporization ratio of the solvent to the captured CO2, is used to evaluate the energy required for regenerating the lean solvent. A higher value of the index indicates that extra solvent needs to be vaporized, as compared to the captured amount of CO2. This index unifies the energy-saving concepts of the pressurized stripper and advanced stripper configurations. The former increases the stripper temperature, which favors CO2 desorbed from the rich solvent, while the latter lowers the top temperature of the stripper, which enhances the CO2 purity at the top. Both methods, which are the pressurized stripper and advanced stripper configuration, can achieve the energy-saving purpose by reducing the vaporization ratio, because a higher CO2 purity at the top leads to lesser solvent required to be vaporized for constant CO2 removal. In addition, the energy reduction achieved by stripper modifications, which include the rich-split process, the interheating process, and the integration of both configurations, is investigated. The results indicate that the energy-saving effect of the rich-split process integrated with interheaters (IHs) is not as promising as the literature claims. Once the design parameters of the rich-split process are selected properly, the rich-split process without IHs can achieve the same energy-saving effect as that achieved by process of integration with IHs.

The aging precipitation behavior of 20Cr-24Ni-6Mo super-austenitic stainless steel processed by conventional casting and twin-roll strip casting

Isothermal aging treatments in the temperature range from 550 to 1150 °C for the aging time range from 2 to 2880 min were carried out on 20Cr-24Ni-6Mo super-austenitic stainless steel plates, which were processed by conventional casting and twin-roll strip casting (TRSC). Precipitation behaviors were comparatively studied, from which Time-Temperature-Precipitation (TTP) curves were developed. The results show that two TTP curves basically exhibited C-shapes and each TTP curve was the superposition of sigma and Laves precipitation kinetics curves. When the temperature was higher than about 825 °C, TTP curves were mainly sigma precipitation kinetics curves. On the contrary, TTP curves were mainly sigma and Laves precipitation kinetics curves. Aging temperatures of the precipitation sensitive interval were about in the range from 875 to 1025 °C. The nose temperature of conventional specimen was about 925 °C and the corresponding incubation time was about 2 min. However, the nose temperature of cast strip (CS) specimen was about 950 °C and the corresponding incubation time was about 4 min. TTP curve of CS specimens moved to the upper right as compared to that of conventional specimens, indicating that the precipitation in CS specimens was delayed. By analyzing the compositional distribution in the conventional and CS specimens after solution treatment, it was found that after the completion of solution treatment, the distribution of alloying elements in the CS plate was more homogeneous than that in conventional plate. Therefore, the conventional specimen was more susceptible to the formation of precipitates in aging treatments.

Degradation Test for Energy-Saving CO2 Absorbent Based on Phase Separation Type Solvent by Aqueous (Amine + Ether) Solution

To mitigate CO2 emission, chemical absorption using alkanolamine solvent is proposed to be the most applicable technology for CO2 capture. However, the alkanolamine solvent possess high energy consumption in regeneration. Thus, it is important that energy consumption in regeneration is reduced. To reduce the energy consumption, we have developed the phase separation solvent for CO2 capture, which consist amine, organic solvent and water. It shows single liquid phase before CO2 absorption though it shows two liquid phases after CO2 absorption. Feature of phase separation solvent is decreasing stripper bottom temperature (e.g. T=90℃). As a result, energy consumption in regeneration can be decreased to 2.9 GJ/t-CO2 or less (Monoethanolamine solvent, 3.8GJ/t-CO2). CO2 solubility of the immiscible type solvent follows the general trend of conventional amine solvents since the ether does not dissolve in amine phase and does not affect the physical property of the amine solution. CO2 solubility in phase separation solvent is almost the same as that of immiscible one at 313 K, though the solubility at 363 K is remarkably small. It means that the phase separation solvent reduces stripper temperature. In addition to reduction of energy consumption, durability is also an important point in order to put into practical use. SO2 is the main acidic impurity in flue gas and will affect amine degradation in CO2 capture. Therefore, this study is conducted durability test under acid gas in order to evaluate the durability of the phase separation absorbent. Durability of the phase separation absorbent under acid gases is evaluated by using test equipment. The compressed gas cylinders provided the feed gases whose flow rates were controlled by mass flow controllers. The gases fed into a static mixer and were mixed. The phase separation solvent is put in a beaker, and absorbs CO2 by blowing mixed acid gas after keeping the constant temperature (323K) with cold water. During regeneration, the phase separation solvent regenerates while keeping the constant temperature (363K) with hot water. In each step, the temperature is kept constant by stirring inside the beaker. To measure amount of absorbed CO2, gas flow rate of outlet during absorption / regeneration is measure by using mass flowmeter. In addition, the composition of the gas at the absorber outlet is analysed by a gas chromatograph.

Bi-material strip based temperature sensor design and optimization through thermo-mechanical multi-physics modeling

ABSTRACTWith the capability of additive manufacturing, complex structures are easily fabricated to achieve various design purposes. In this work, a bi-material strip temperature sensor with complex periodic pattern design is purposed and investigated through both the analytical modeling and multi-physics finite element analysis. Three design patterns are considered: standard, E-shape and S-shape. In the standard solid strip design, the curvature of the bi-material strip under temperature variation is in a linear relationship with the coefficient of thermal expansion (CTE) difference, but in a reciprocal relationship with the strip thickness. The curvature of the bi-material strip depends on the Young’s modulus ratio and layer thickness ratio of the two materials, but is independent of the magnitude of the materials’ Young’s modulus. Based on analytical derivation and numerical validation, the optimized design parameters can be provided. Compared to S-shape pattern design, E-shape pattern design can significantly increase the temperature sensitivity of the bi-material strip. An analytical prediction of the E-shape pattern’s temperature sensitivity is introduced and discussed. This work proves the concept that new design space becomes available with the capability of additive manufacturing, and provides the general design guideline for a bi-material strip based temperature sensor with possible design patterns.

An Efficient Spraying Method with Cyclodextrine‐drived Aqueous Stripper for Removing of Organic Photoresist on Indium Tin Oxide Surface

The chemical mechanism of inducing polymer breakage in a photoresist layer plays an important role in the photoresist removal from an indium tin oxide substrate. The spray structure for delivering the relevant functional material is involved in the process of binding and dissolving the PR (photoresist) material. This presents an efficient spraying process of removing the photoresist layer formed on a 260‐nm‐thick indium tin oxide substrate with a CD (cyclodextrine)‐drived aqueous stripper, simultaneously implementing proper mass transfer and heat transfer. It was taken to achieve an economical stripper consumption management by limiting the modified Weber number to 200 and the spray distance to 100 mm. As a result, stable removal performance was achieved, with optical and electric properties varying within the range of 1%, in CD drived aqueous stripping conditions (water content of the stripper composition ≤71%, stripper temperature = 40°C, and stripping time = 40 s).

Energy requirements for the in-situ recovery of biobutanol via gas stripping

Biobutanol has been accepted as the preferred renewable, bio-based additive or replacement for petroleum based fuels. The production of biobutanol has, however, encountered low productivity and titres due to a high toxicity of butanol to the bacteria. This leads to an energy intensive distillation step. Gas stripping has been presented as a method of good potential because of its simplicity and clean operation, with the ability to concentrate the product by several fold. However, these investigations have lacked rigorous analysis of energy requirements, with the energy required at best being estimated using simplified assumptions. A detailed assessment of the energy requirements for gas stripping is presented in this work. This includes a rigorous analysis of the key operating variables of 21 experimental mass balance data sets from 16 investigations in the literature. Higher butanol concentrations in the culture and higher stripping temperatures are shown to be the two most significant parameters influencing the energy efficiency of the process. Gas stripping with distillation consumes 34.2 to 380 MJ/kg butanol and is 41–370% less energy efficient than the use of distillation only for product recovery. Hence an integrated analysis of the production and separation steps is essential to determine overall process benefits.

A temperature-compensated fiber Bragg grating sensor system based on digital filtering for monitoring the pantograph–catenary contact force

Optical sensors based on fiber Bragg gratings have become an important type of sensing element for strain measurements. In this study, fiber Bragg grating strain sensors and corresponding reference temperature sensors were integrated into a pantograph strip. The results of an online test indicated that the temperature of the pantograph strip impacting the strain measurement reaches about 80 ℃ while the vehicle was running. In addition, Fourier analysis showed that the energies of the temperature measurement signals dominated the relatively low-frequency band (less than 0.02 Hz), whereas the strain signals prevailed in the relatively high-frequency band. Thus, a novel method based on a digital filtering technique was proposed for temperature compensation in fiber Bragg grating sensor systems for monitoring the conditions in electrified pantograph–catenary systems. A Butterworth high-pass filter was designed to reject the temperature-related signal component with a stopband and to capture the real strain in the passband in frequency domain. To achieve this filtering, the cutoff frequencies and the filter order were calculated adaptively according to the frequency-domain characteristics of the measured temperature signal. With the designed filter, the temperature effect to the strain signals can be eliminated so that the strain can be estimated accurately. In comparison with the traditional temperature compensation technique, the proposed method is more effective in terms of estimating the real strain of the pantograph strip in practical applications. Compensated by the proposed method, the time-domain and frequency-domain analyses of the contact force denote the frequencies corresponding to the support span, and the dropper can be distinguished. Further, the first-order (4 Hz) and second-order (8.3 Hz) natural frequencies of the pantograph are visible in the measurements from catenary sections, which demonstrates the sufficiency and rationality of the proposed temperature compensation method for fiber Bragg grating sensor systems.

Influence of Steel Strip Temperature in Formation Zinc Dross During Process Production Using Continuous Galvanizing Line (CGL) Machine

To control the occurrence of zinc dross during galvanizing process using production Continuous Galvanizing Line (CGL) machine, it is necessary to control steel strip temperature before entry into zinc bath. The Steel strip temperature controls were variable at 320°C and 400°C and zinc bath temperature was fix at temperature 460°C. At temperature steel strips of 320°C, zinc bath was checked using spectrometry, the results of Fe content 0.1293% and Al 0.0759%, because the solubility of Al is lower than Fe, the dross occurs become bottom dross. If the zinc dross change become bottom dross, the bottom dross could decrease quality of product and life time of zinc pot, because bottom dross settled at the floor. Bottom dross properties very hard and absorb heating, then at that position bottom dross make hot spot in the floor, finally zinc pot leakage. At temperature steel strip 400°C, the results content of Al 0.1667% and Fe 0.1217%, due to high temperature steel strip make solubility of Al become higher than Fe, therefore float at the zinc bath become top dross.

Research of Rolling Process with Warm for Cold-Rolled Non-Oriented Electrical Steel

The rolling process with warm for cold-rolled non-oriented electrical steel in pickling and rolling and continuous annealing was studied. Research shows when feeding the hot plate for Pickling and rolling mill in 100~120°C, pickling steel is almost no temperature rise, with the temperature of hot rolled silicon steel pickling effect is good, the cleaning rate reaches 100%; the steel sheet is stable running in looper for the strip temperature softening effect and shape of rolled strip is good, deviation below 8μm. Cold rolled plate feeding in 60~80°C for continuous annealing unit, the plate is almost no heating in Alkaline wash. Alkaline wash effect is good for the cold rolled plate with temperature steel, plate surface defect can be significantly reduced and wash rate is up to 100%; steel plate with temperature is not deviation in continuous annealing looper for softening. In addition, organization, texture, the second particles and magnetic energy also were studied. It was found that the steel sheets’ microstructure is uniform after cold rolling, the grain is evenly stretched; belt warm rolling and the grain orientation of the cold-rolled sheet steel texture is obviously, which formed two main categories with {111} <uvw> and {hkl} <110> texture; after annealing, the second particles MnS and AlN particles has been roughened and close to the magnetic domain size, which reduce the obstacle second phase particles on the magnetic domains; Compared with the conventional process, the iron loss decreased slightly, magnetic induction increased slightly.

A combination of ammonia stripping and low temperature thermal pre-treatment improves anaerobic post-digestion of the supernatant from organic fraction of municipal solid waste treatment

Municipal Solid Waste is mostly composed of organic material which is often treated in anaerobic reactors in waste treatment plants. In most cases, the obtained digestate undergoes a solid/liquid separation step, producing a liquid fraction (known as anaerobic supernatant) rich in ammonium nitrogen that has to be further treated in order to meet discharge standards. The objective of the present work was to evaluate the feasibility of anaerobic post-digestion (37 °C) of a supernatant rich in carbon and nitrogen from a municipal waste treatment plant. In order to increase the efficiency of the process, a combined pre-treatment consisting of a low-temperature thermal process (75 °C) and ammonia stripping (1.3 Lair Lsupernatant−1 min−1) was applied. The effects of pre-treatment contact time (4 and 8 h) and the hydraulic retention time (HRT) in the anaerobic reactor (20–40 d) were studied. Supernatant pre-treatment with 8-h contact time caused 13% organic matter solubilisation, thus improving methanisation by 18% when the HRT was 40 d. At the same time, ammonia stripping allowed to maintain ammonia concentration in the digester below inhibitory values (less than 100 mg N-NH3 L−1) enabling therefore high methanogenic activity (>0.23 g COD g−1 VS d−1). The final effluent characteristics (low total ammonia nitrogen and aerobically biodegradable organic matter levels) would permit implementing subsequent less energy intensive and more environmental-friendly technologies (such as partial nitritation/anammox) to comply with discharge limits.

Investigating the performance and thermodynamic efficiency of CO2 reactive absorption – A solvent comparison study

The capture of the CO2 released in the atmosphere by various sources is a key issue included in all environmental related European new legislation and roadmaps. Among Carbon Capture Systems (CCS), post-combustion reactive absorption is one of the most efficient and easily deployable methods. In specific, amine aqueous solvents ensure high absorption efficiency due to their reactivity with CO2. Monoethanolamine (MEA) and a mixture of Monoethanolamine and Piperazine, 30 MEA/18 PZ % wt., were found to achieve very satisfying levels of CO2 capture. For these solvents, a simulation of the entire CO2 capture unit was performed in Aspen Plus software. For the MEA case, a parametric analysis was performed to determine the impact of the absorber inlet liquid temperature, gas and liquid flow rates on CO2 mole fraction, reboiler heat duty and stripper temperature profile. The absorber inlet liquid temperature was found to be the most important factor influencing the absorption performance as well as the reboiler heat duty required for regeneration. The absorber inlet gas and liquid flow rates had also impact on the liquid temperature profiles in the absorber and on the energy cost. Comparing the two solvents, the MDEA/PZ solvents captured 99% of the CO2 of the flue gas while MEA only 80% for the conditions of the simulation. For the reference system with MEA, overall exergy efficiency was calculated considering the carbon capture unit as an integrated thermodynamic system. The overall exergy efficiency of the MEA system was calculated 23.8%, while the respective value for the MDEA/PZ system was calculated 26.1%. Evaluating the two main columns of the system in terms of exergy efficiency, the absorber showed low values of efficiency for both solvents, in specific 16.3% for MEA and 22.6% for MDEA/PZ, while the desorber had higher efficiencies, 27.8% for MEA and 34.3% for MDEA/PZ. In general, MDEA/PZ system was characterized by higher thermodynamic efficiencies both in system and individual column level. Furthermore, the analysis for the MDEA/PZ system resulted to a 5% lower reboiler heat duty than in the MEA case.