| 1. |
- Andersson, Viktor, 1983, et al.
(author)
-
Efficient Utilization of Industrial Excess Heat for Post-combustion CO2 Capture: An Oil Refinery Sector Case Study
- 2014
-
In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 63, s. 6548-6556
-
Conference paper (peer-reviewed)abstract
- A key issue in post-combustion carbon capture is the choice of absorbent. In this paper two different absorbents, monoethanolamine (MEA) and ammonia (NH3), have been modeled in Aspen Plus at different temperatures for possible implementation at an oil refinery. The focus of investigation is the possibilities of heat integration between the oil refinery and the carbon capture process and how these possibilities could change in a future situation where energy efficiency measures have been implemented.The results show that if only using excess heat from the refinery for heating of the carbon capture process, the MEA process can capture more CO2 than the NH3 process. It is shown that the configuration requiring least supplementary heat when applying carbon capture to all flue gases is MEA at 120 °C.The temperature profile of the excess heat from the refinery suits the MEA and NH3 processes differently. The NH3 process would benefit from a flat section above 100 °C to better integrate the heat needed to reduce slip, while the MEA process only needs heat at stripper temperature.
|
|
| 2. |
- Ekvall, Thomas, 1986, et al.
(author)
-
The use of waste fractions for co-combustion in an aluminium recovery smelter
- 2016
-
In: IMPACTS OF FUEL QUALITY ON POWER PRODUCTION.
-
Conference paper (other academic/artistic)abstract
- Fossil energy resources are widely accepted to be the main cause for the climate changes we are facing. Large efforts are therefore invested in finding alternative energy resources and to improve resource efficiency in order to reduce fossil CO2 emissions. For example, the recycling of used products and materials translates into large energy savings. Different product and materials are more or less suitable for material recycling. Fractions of products which are difficult to recycle may instead be suitable for energy recovery, i.e. the material may be used as a fuel which improves the cost and resource efficiency of the recycling process. In this work five different waste fractions were evaluated for co-combustion purposes in a secondary aluminium smelting process. The work has been carried out by performing detailed gas phase reaction simulations. Based on these simulations fuel alternative B seems to be the most promising alternative. However, it has also been concluded that further investigations toned to be made in order to eliminate some of the uncertainties identified in this work.
|
|
| 3. |
- Evangelopoulos, Panagiotis, et al.
(author)
-
Investigation on the low-temperature pyrolysis of automotive shredder residue (ASR) for energy recovery and metal recycling
- 2018
-
In: Waste Management. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0956-053X .- 1879-2456. ; 76, s. 507-515
-
Journal article (peer-reviewed)abstract
- The automotive shredder residue (ASR) or shredder light fraction (SLF) is the remaining fraction from the metal recovery of end-of-life vehicles (ELVs). While processes for metal recovery from ELVs are well developed, the similar process for ASR remains a challenge. In this work, low-temperature pyrolysis of the ASR fraction was investigated under the assumption that a low temperature and inert environment would enhance the metal recovery, i.e. the metals would not be further oxidised from their original state and the organic material could be separated from the metals in the form of volatiles and char. Pyrolysis experiments were performed in a tube reactor operating at 300, 400 and 500 degrees C. The gas and oil obtained by pyrolysis were analysed by micro-GC (micro-Gas Chromatography) and GC/MS (Gas Chromatography/Mass Spectrometry), respectively. It was found that the gas produced contained a high amount of CO2, limiting the energy recovery from this fraction. The oil consisted of a high concentration of phenolic and aromatic compounds. The solid residue was crushed and fractionated into different particle sizes for further characterization. The pyrolysis temperature of 300 degrees C was found to be insufficient for metal liberation, while the char was easier to crush at tested temperature of 400 and 500 degrees C. The intermediate temperature of 400 degrees C is then suggested for the process to keep the energy consumption low.
|
|
| 4. |
- Halstensen, M., et al.
(author)
-
Equilibrium Measurements of the NH3-CO2-H2O System: Speciation Based on Raman Spectroscopy and Multivariate Modeling
- 2017
-
In: Journal of Chemistry. - : Hindawi Limited. - 2090-9071 .- 2090-9063. ; 2017, s. Article Number: 7590506-
-
Journal article (peer-reviewed)abstract
- Liquid speciation is important for reliable process design and optimization of gas-liquid absorption process. Liquid-phase speciation methods are currently available, although they involve tedious and time-consuming laboratory work. Raman spectroscopy is well suited for in situ monitoring of aqueous chemical reactions. Here, we report on the development of a method for speciation of the CO2-NH3-H-2 O equilibrium using Raman spectroscopy and PLS-R modeling. The quantification methodology presented here offers a novel approach to provide rapid and reliable predictions of the carbon distribution of the CO2-NH3-H-2 O system, which may be used for process control and optimization. Validation of the reported speciation method which is based on independent, known, NH3-CO2-H2O solutions shows estimated prediction uncertainties for carbonate, bicarbonate, and carbamate of 6.45 mmol/kg H2O, 34.39 mmol/kg H2O, and 100.9mmol/kg H2O, respectively.
|
|
| 5. |
- Jilvero, Henrik, 1984
(author)
-
Ammonia as an Absorbent of Carbon Dioxide in Post-Combustion Capture - an Experimental, Technical and Economic Process Evaluation
- 2014
-
Doctoral thesis (other academic/artistic)abstract
- Carbon capture and storage is vital to facilitating the transition from our current fossil fuel-based energy system to a sustainable energy system. The concept of post-combustion capture is based on the selective chemical absorption of carbon dioxide (CO2). The highly concentrated CO2 stream that is suitable for storage is generated by heat-induced regeneration of the solvent. In this work, ammonia is evaluated as an absorbent of CO2 in post-combustion capture processes. The major goals of this thesis are to define favorable applications and local conditions for ammonia-based post-combustion capture processes. The current benchmarking absorbent, monoethanolamine (MEA), has inherent problems is associated with specific drawbacks, such as a high heat requirement for regeneration and a tendency to undergo degradation during operation. Several novel absorbents, including ammonia, have been proposed as being superior to MEA in these aspects. The major disadvantage of ammonia is its volatility, which results in loss of absorbent (slip).This thesis reveals the results of experimental, technical and economic performance analyses. To evaluate the capture process, validation of thermodynamic models of the NH3-CO2-H2O system is required. These thermodynamic models rely on a comprehensive experimental data on the solid-liquid-gas equilibrium for all operating conditions. This work presents new gas-liquid equilibrium data for temperatures that are relevant to the absorber (
|
|
| 6. |
- Jilvero, Henrik, 1984
(author)
-
Ammonia-Based Post-Combustion Capture of Carbon Dioxide
- 2013
-
Licentiate thesis (other academic/artistic)abstract
- Post-combustion capture of carbon dioxide is one of the measures to reduce emissions of carbon dioxide from large point source emitters. In post-combustion capture the carbon dioxide is absorbed from the flue gas by means of a liquid absorbent. In this thesis, ammonia is evaluated as absorbent of carbon dioxide in a post-combustion capture application. The major energy penalty for capturing carbon dioxide is, in the case of post-combustion capture, the heat required to release the carbon dioxide from the absorbent, also called the heat of regeneration. The overall aim of this thesis is to determine the heat requirement of ammonia regeneration and to evaluate the consequences of integrating post-combustion capture with an existing coal-fired power plant. The primary evaluation tool in this work is equilibrium-based thermodynamic modeling. Three thermodynamic models proposed in literature for the NH3-CO2-H2O system are evaluated. A literature review in this work revealed missing data for equilibrium partial pressures of carbon dioxide and ammonia at 0 - 20°C, which is the typical temperature range for post-combustion capture with ammonia.An experimental methodology was therefore established in Paper I in which the aim was to determine the partial pressures of ammonia and carbon dioxide at 10 and 20°C. The experimental setup consisted of an equilibrium cell connected to a gas chromatograph. The experimental conditions included 5.7 and 10.7 wt% NH3 and CO2-loadings between 0.15 - 0.75. The results provide additional data points in the partial pressure range 0.1 - 20 kPa and 0.01 - 10 kPa for ammonia and carbon dioxide, respectively.In Paper II the CO2 capture cycle is simulated in the process simulation software Aspen Plus. The thermodynamic models form the foundation for the flow sheet process modeling. The heat requirement for regeneration is evaluated for NH3 concentrations ranging from 2 to 20% and the lean CO2-loading is varied between 0.2 - 0.5. The specific heat requirement was determined to be 2500 kJ/kg CO2 captured. There is a minimum of 2100 kJ/kg CO2 captured at a CO2-loading of 0.5, just where solid precipitation starts. However, at these conditions the equilibrium sets a limit to the capture efficiency of 50%. Furthermore, it is concluded that the major reason for the low heat requirement for ammonia regeneration is not a low heat of reaction but a low heat of vaporization, due to the pressurized desorption. In Paper III, the ammonia-based post-combustion technology “Chilled Ammonia Process” is thermally integrated with a coal-fired power plant. It is concluded that the electric efficiency of the power plant will decrease with 9.2%-points. Yet, this figure depends strongly on the available cooling water temperature. Access to low temperature cooling water greatly enhances the performance of the capture process. A 10°C higher cooling water temperature could increase the energy penalty of the power plant with almost one percentage point.
|
|
| 7. |
- Jilvero, Henrik, 1984, et al.
(author)
-
Ammonia-based post combustion - The techno-economics of controlling ammonia emissions
- 2015
-
In: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 37, s. 441-450
-
Journal article (peer-reviewed)abstract
- An important process consideration in ammonia-based, post-combustion CO2 capture is the volatility of ammonia. Consequently, there is a need to adopt control measures to minimize the emission (the slip) of ammonia from such processes. This work evaluates techno-economic aspects of methods to reduce the ammonia slip. The emission of ammonia is required to be below 10 ppm while the ammonia slip from the absorber in an ammonia-based process may exceed 10%. The ammonia control methods that are evaluated in this work are staged absorption, ammonia abatement cycle, chilled absorption and acid wash. The control methods are also evaluated with respect to local conditions, such as cooling water temperature and flue gas CO2 concentration. Rate- and equilibrium-based thermodynamic modelling forms the basis for the evaluation process. A simplified economic estimation method is used to evaluate the utility cost of ammonia control designs under different operating conditions. The economic estimation shows that for the best case conditions the utility cost are as low as 1.5(sic)/tCO(2). However, the cost of the ammonia control may be more than tenfold when the available cooling water temperature is increased (>5 degrees) or when the flue gas CO2 concentration is decreased (
|
|
| 8. |
- Jilvero, Henrik, 1984, et al.
(author)
-
Equilibrium measurements of the NH3-CO2-H2O system - measurement and evaluation of vapor-liquid equilibrium data at low temperatures
- 2015
-
In: Fluid Phase Equilibria. - : Elsevier BV. - 0378-3812. ; 385, s. 237-247
-
Journal article (peer-reviewed)abstract
- The equilibrium behavior of carbon dioxide (CO2) in aqueous ammonia at low temperatures was studied by means of experiments and modeling. The low-temperature conditions of this system are of interest for the development of ammonia-based CO2 capture. This study includes experimental analyses of the vapor and liquid phases to determine the fate of CO2 in aqueous ammonia. The partial pressure of CO2 at equilibrium was measured in a gas chromatograph. The vapor phase was assessed with ammonia concentrations at 5 and 10 wt%, CO2-loadings in the range of 0.15-0.75, and at the temperatures of 10 degrees C, 20 degrees C, and 40 degrees C. The liquid-phase carbon distribution was determined based on Raman spectroscopy and partial least-squares regression modeling. Speciation of the liquid phase was determined at 5 wt% and 10 wt%, CO2-loadings in the range of 0-0.6, and room temperature (25 degrees C). Two thermodynamic models of the NH3-CO2-H2O system were evaluated with respect to the measured data. For the prediction of the partial pressure of CO2, the model devised by Que and Chen [6] proved to be the most accurate, while for the liquid-phase predictions, there was no significant difference between the models in terms of accuracy.
|
|
| 9. |
- Jilvero, Henrik, 1984, et al.
(author)
-
Heat requirement for regeneration of aqueous ammonia in post-combustion carbon dioxide capture
- 2012
-
In: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 11, s. 181-187
-
Journal article (peer-reviewed)abstract
- The present work evaluates ammonia as a carbon dioxide (CO2) solvent for post-combustion carbon capture, focusing on the thermal performance of the ammonia regeneration process and the operating conditions for the aqueous ammonia process. The main parameters investigated were the CO2-loading of the lean solution (0.2-0.5) and the ammonia concentration (2-20%). An equilibrium-based electrolyte model was used in process simulation software to evaluate the performance of the ammonia regeneration. The heat requirement was approximately 2500 kJ/kg CO2 captured. Running conditions in which the precipitation of solids occurred did not enhance the thermal performance. The main reaction pathway for the absorption of CO2 was identified as the formation of bicarbonate through the reaction of ammonia with CO2. The heat of reaction required to desorb CO2 of ammonia was similar to that required for monoethanolamine (MEA). However, significantly less water was evaporated during the regeneration process with ammonia, resulting in a lower heat requirement for regeneration.
|
|
| 10. |
- Jilvero, Henrik, 1984, et al.
(author)
-
Heat requirement of CO2 absorption by aqueous ammonia
- 2011
-
In: 1st Post Combustion Capture Conference.
-
Conference paper (other academic/artistic)abstract
- Aqueous ammonia has lately emerged as a promising absorbent of CO2 in post-combustion capture applications,often referred to as the chilled ammonia process (CAP). The heat required for regeneration, i.e. the reboiler duty(kJ/kg CO2), is a crucial parameter for all absorbents. For the CAP, the required reboiler duty presented in literatureranges from 1,500 to 4,200 kJ/kg CO2 [1-6]. This is a wide range with crucial consequences for the feasibility of theprocess. The aim of this work is to review the different sources in order to explain the large difference in heatrequirement.
|
|
