• Energy Research

Abstract This work sought to estimate the economic and environmental potential of palm kernel shell for hydrogen production as energy vector in Norte de Santander, Colombia. A field research determined that the department generates monthly 14082 t of palm biomass of which 12501 of palm kernel shell remain available for their use. The proximate and ultimate analyses of the palm kernel shell report high heating value (19.53 MJ/kg) compared with other agro-industrial biomasses, high content of volatile material (69.82% w/w) and fixed carbon (21.68% w/w), promoters of chemical reactions in pyrolysis and gasification processes, respectively. In the Aspen Plus® simulation process of the palm kernel shell gasification at 900 °C and steam/biomass ratio of 1.5, a yield is obtained of hydrogen production of 40.7%, equivalent to a monthly production in Norte de Santander of 51.6 t. Using H2 in the generation of electric power permits producing 470.9 MWh/month that represent theoretical utilities of US$27734.5. In another scenario, 55848.8 gal/month of gasoline are substituted, equivalent to US$11708.6 through the sale of carbon credits. Regarding diesel, 45905.1 gal are replaced per month, which add US$9725.4 through the commercial transaction in the carbon market. It is concluded that using palm kernel shell as primary source to obtain H2, has, in principle, a favorable economic and environmental impact for sustainable development of the department of Norte de Santander, besides contributing to the knowledge base on the penetration of this vector in Colombia’s energy matrix; however, more detailed technical and economic studies are needed to conclude regarding the economic viability of this energy conversion process.

Abstract This paper presents the results of co-gasification of Sub-bituminous coal type A (SubbA coal) with palm kernel shell (PKS) in a fluidized bed gasifier to meet the energy requirements for baking 300 tons/day of bricks in a tunnel kiln. Standardized operation of the co-gasification process of the SubbA coal – PKS 90/10 wt.% mixture was confirmed for a 24 h run. The reactor has the capacity to process up to 700 kg/h of the mixture, using air and an air/steam as the gasifying agent at 800°C, with an equivalent ratio of air/fuel (ER) between 0.5 and 0.7 and a steam/fuel ratio of 0.2. The product syngas had a HHV of 5.0 MJ/Nm3 that efficiently substitutes and the traditional use of pulverized coal by means of carbojets into the tunnel kiln without affecting the production process, while using a much cleaner gas to cook the bricks with lower emissions. This demonstrating the synergy existing in this coupling. Positive results of these experiments can enhance figure use of coal in a clean manner. This technology is mature enough to be implemented as a continuous energy supply to industrial processes that currently use traditional combustion for heat.

Abstract Corncob is one of the most abundant agro-industrial wastes globally. It represents a bioenergy feedstock of 1500–5500 million tons per year. The shape and size of the corncob are suitable for gasification without pretreatment (size reduction, densification, or drying) in a downdraft gasifier. However, its volatile content (about 80% DAF) can generate high tar content, representing a challenge to adopt this technology. In the present work, an evaluation of the effect of air-steam mixture and calcium carbonate CaCO3 as a promoter of both reforming and gasification reaction was carried out using corn cob without grains as raw material in a 40 kW gasifier. An analysis of variance of four experimental treatments was used to determine the main statistical and interactive effects on the syngas composition, hydrogen yield (yH2), syngas lower heating value (LHVgas), and cold gas efficiency (CGE). Results reveal the highest gasification performance achieved hydrogen production yields of 310 Nml/g, an LHVgas value of 4.8 MJ/Nm3, and cold gas efficiency of 59.18% with steam and CaCO3. Statistical analysis indicated that CaCO3 and steam influence H2 production by increasing 15.8% and 10.8%, respectively, with a CaCO3/biomass ratio of 1% (w/w) and a Steam/biomass ratio of 11% (w/w). Main statistical effects were found for CGE increase of 5% with the addition of steam, 10% with CaCO3, and synergy of 10% using CaCO3 and steam simultaneously.

A new approach is proposed to obtain the kinetic parameters of biomass pyrolysis mixed with calcium catalyst. This approach involves the optimization of least squares (LS) with the Coats-Redfern integral method to avoid mathematical biases that may appear when applying the linear regression approach. The method was applied to the TGA data of pyrolysis of corn cob and corn cob mixed with 20 or 40 % by weight of CaO or CaCO3 under N2 atmosphere at temperatures between 25 and 700 °C. For raw cob, r2 reaches 0.997. For corn cob mixed with 20 % by weight of CaO or CaCO3, r2 reached 0.996-0.998, and for 40 % by weight, r2 reached 0.836-0.957. Applying this method, the activation energy (EA) value of the raw cob pyrolysis is 58.35 kJ mol-1, while the addition of CaO or CaCO3 increases the EA to 69.33 and 66.07 kJ mol-1, respectively. The method is simple to use and allows reliable values of kinetic parameters.

Abstract The hydrogen production process from palm kernel shell (PKS) is modeled and simulated by a steady-state gasification system using Aspen PLUS®. The kinetic parameters of the gasification are determined by employing thermogravimetric analysis (TG/DTG) using two gasifying agents (CO2 and steam) and applying three semi-empirical kinetic models to interpret the experimental results (linear model, grain model, and volumetric model). The process was subjected to different temperatures (750–950 °C) and different compositions of the steam/biomass ratio (S/B) (0–2.5). It is obtained that the linear model and the grain model have the best R2 with the gasification results of the PKS with steam (0.966) and CO2 (0.965), respectively. The steam reaction kinetic parameters obtained were E = 125.79 K J / m o l and A = 26.23 s − 1 , and for the reaction with CO2, they were E = 99.87 K J / m o l and A = 6.3 s − 1 . The production yield of H2 (109 g H2/PKS kg) is reached at the highest temperature (950 °C) and the lowest S/B ratio (0). It is concluded that the model can predict with greater precision the hydrogen composition in the syngas, with a 0.135 mean square error, compared to other authors that present a 0.282 mean square error.

This research sought to produce biodiesel from waste frying oil (WFO) from chicken grills by using chemical transesterification to evaluate quality conditions and the yield of the biodiesel obtained. For this, acid esterification and basic transesterification were applied under the following conditions: reaction temperature 60°𝐶, catalyst concentration of 1% (m/m) KOH, oil:alcohol 1: 6 𝑚𝑜𝑙𝑎𝑟 𝑟𝑎𝑡𝑖𝑜, and two reaction times (55 𝑎𝑛𝑑 70𝑚𝑖𝑛) for the transesterification. The physicochemical properties of the raw material were analyzed (i.e., density, humidity, kinematic viscosity, fatty acid profile, acidity index, peroxides, and saponification) where the WFO showed high contents of oleic acid (42.45%) and palmitic acid (33.52%), which are fundamental for biodiesel production. Chemical transesterification under the conditions of 60°𝐶, 1% KOH, and 70𝑚𝑖𝑛 obtained the best yield by presenting a high conversion percentage (96.15%) and an acid number of 1.33𝑚𝑚𝐾𝑂𝐻/𝑔, according to ASTM D6751 and EN 14214 international standards. 8 p.

Many industries have taken interest in the use of coal gasification for the production of chemicals and fuels. This gasification can be carried out inside a fluidized bed reactor. This non-ideal reactor is difficult to predict due to the complex physical phenomena and the different chemical changes that the feedstock undergoes. The lack of a good model to simulate the reactor’s behavior produces less efficient processes and plant designs. Various approaches to the proper simulation of such reactor have been proposed. In this paper, a new model is developed for the simulation of a pressurized bubbling fluidized bed (PBFB) gasifier that rigorously models the physical phenomena and the chemical changes of the feedstock inside the reactor. In the model, the reactor is divided into three sections; devolatilization, volatile reactions and combustion-gasification. The simulation is validated against experimental data reported in the literature and compared with other models proposed by different authors; once the model is validated, the dependence of the syngas composition on operational pressure, temperature, steam/coal and air/coal ratios are studied. The results of this article show how this model satisfactorily predicts the performance of PBFB gasifiers.