K. Pacheco-Pérez ¹, M. Baia-Olivares ¹, D. Meza-González ¹, Á. D. González-Delgado ¹

Affiliations
1 Department of Chemical Engineering, University of Cartagena, Cartagena, Bolívar, CO

Abstract

Background: The extraction of oil from African palm fruits (Elaeis guineensis) generates solid wastes such as Empty Fruit Bunch (EFB), mesocarp fibers, palm frond, palm trunk and palm kernel shell, which exhibit great capability to be employed for producing value-added products, such as hydrogen. Objectives: In this work, exergy analysis of hydrogen production from EFB was carried out using indirect gasification and purification with selexol in order to evaluate overall efficiency of this process. Methods/Analysis: Based on operational conditions (mass flow, temperature and pressure), the process was modeled using a commercial process simulation software, physical and chemical exergies of streams were calculated, stage and overall irreversibilities and exergy efficiencies were found. Stages that require improvements were identified and sensibility analysis was implemented to increase overall exergy efficiency. Findings: It was found that 36 t/h of EFB produce 2.5522 t/h of hydrogen with an overall exergy efficiency of 20%. Novelty/Improvement: Sensibility analysis suggested that process efficiency in terms of exergy could be improved by recycling selexol to hydrogen separation stage, which led to increase the products exergy to 469,747.05 MJ/h.

Keywords

Empty Fruit Bunch, Exergy Analysis, Hydrogen, Palm Oil, Solid Waste

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C. Tejada-Tovar ¹, A. Villabona-Ortíz ¹, A. Herrera-Barros ¹, Á. D. González-Delgado ¹, L. Garcés ¹

Affiliations
1 Department of Chemical Engineering, University of Cartagena, Cartagena, Bolívar, CO

Abstract

Background: The increasing concentration of heavy metal pollutants as hexavalent chromium ions has gained attention due to its effect on the environment. Hence, different methods have been applied for removing Cr (VI) in aqueous solution and bioadsorption seems to be a cost-effective alternative due to the use of lignocellulosic materials as biosorbents. Objectives: This paper is focused on a comparative study of adsorption capacity of Cassava Peel (CP), Lemon Peel (LP) and its chemical modification with citric acid (CP-CA and LP-CA). Methods/Analysis: The adsorption process was carried out in batch and continuous systems in order to determine the effects of biosorbent particle size and pH on Cr (VI) removal yield. Findings: It was obtained that removal yield of 54% and 56% were obtained for unmodified cassava peel and citric acid-modified cassava peel, respectively. In addition, LP-CA showed higher removal yield (48%) than LP (43%), which suggested that chemical modification, improves biosorbent performance. The Cr (VI) ions were desorbed using a solution of HCl, and then the biomass was used in three adsorption cycles to determine its reusability. The kinetic model was adjusted to the pseudo-second order model and Elovich’s model for both modified and unmodified biomasses regarding adsorption isotherms. Freundlich model is the one that best describes the adsorption process. Novelty/Improvement: The good performance of these biosorbents in aqueous solution of Cr (VI) ions make them promising candidate for removing of heavy metals water pollutants.

Keywords

Adsorption, Biomass, Biosorbent, Chromium, Heavy Metal

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K. Ojeda-Delgado ¹, Á. D. González-Delgado ², E. Sánchez-Tuirán ¹

Affiliations
1 Department of Chemical Engineering, Process Design and Biomass Utilization Research Group (IDAB), University of Cartagena, Cartagena, Bolívar, CO
2 Nano materials and Computer Aided Process Engineering Research Group (NIPAC), University of Cartagena, Cartagena, Bolívar, CO

Abstract

Background: Bioethanol is one of the most important biofuels because it has been produced from residual biomass such as corn stover, sugarcane bagasse, agricultural waste, among others. Bioethanol production from non-food biomass represents an opportunity for the biofuels industry to use raw materials in countries with high agricultural development, providing new alternatives for increasing the global production of biofuels. Therefore, process technologies have to be analyzed in order to guarantee the real energy gain in the biofuels industry through exergy analysis and computer-aided system engineering. Objectives: In this work, exergy analysis and heat integration methodologies were applied to evaluate hydrolysis and fermentation technologies when steam explosion pretreatment was used as pathway. Methods/Analysis: Bagasse from sugar industry was considered as raw material for bioethanol production. This residual lignocellulosic biomass was pretreated through catalyzed steam explosion and sent to different process configurations such as Separated Hydrolysis and Fermentation (SHF), Simultaneous Saccharification and Fermentation (SSF), and Simultaneous Saccharification and Co-Fermentation (SSCF). The three processes were analyzed using exergy analysis criteria and the best alternative was integrated to reduce heating and cooling utilities in the process and to improve the energy profile for the bioethanol process. Findings: It was found that the highest exergy efficient was obtained when SSCF technology was used after catalyzed steam explosion pretreatment in comparison with SHF and SSF alternatives. Application of heat integration methodologies reduced cooling utilities by 57.7% and heating utilities by 63.4%. Novelty/Improvement: Implementation of computer-aided process, heat integration and exergy analysis allowed to compare and evaluate bioethanol technologies in order to reduce the energy requirements for the biofuel process and increase the net energy gain.

Keywords

Bioethanol, Catalyzed Steam Explosion, Exergy, Heat Integration, Hydrolysis

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M. Ochoa-García ¹, L. Tejeda-López ¹, K. Ojeda-Delgado ¹, Á. D. González-Delgado ², E. Sánchez-Tuirán ¹

Affiliations
1 Department of Chemical Engineering, Process Design and Biomass Utilization Research Group (IDAB), University of Cartagena, Cartagena, Bolívar, CO
2 Department of Chemical Engineering, Nanomaterials and Computer Aided Process Engineering Research Group (NIPAC), University of Cartagena, Cartagena, Bolívar, CO

Abstract

Background: Microalgae have gained certain attention globally as feedstock for biodiesel production due to its fast growth rate and high potential yield of bio-fuel. Objectives: This work is focused on applying heat integration by thermal pinch point technique to a third generation biodiesel production process using Chlorella vulgaris as feedstock. Methods/Analysis: This case of study was simulated through commercial industrial process simulation software. A Cascade Diagram (CD) was constructed by defining temperature intervals and performing heat balance around them. The CD provided information about minimum cooling and heating utilities usage and maximum integrated heat exchange. In addition, a HEN was sensitized to achieve utilities targets. Findings: It was found that heat integration reduced cooling utilities and heating utilities by 38.67 and 100%, respectively, which reduces total operating costs when compared to base case. Novelty/Improvement: These results suggested that operating cost of biodiesel production from microalgae can be reduced by performing heat integration that represents an attractive process improvement for making biodiesel cost-competitive with other energy sources.

Keywords

Biodiesel, Heat Integration, Pinch Point, Utilities, CAPE

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