Enhancing Co-Gasification of Coconut Shell by reusing Char

In this study, a dryer with a waste heat recovery unit, using coconut shells as the base material for gasification was compared with electric and kerosene dryers in terms of drying curve pattern, rate of dying, cost of drying and quality of fresh dried pulverized kernel under the dry processing method of virgin coconut oil production. Dried pulverized kernel samples from each dryer were tested for basic quality parameters, taking desiccated coconut samples as the control according to Sri Lankan standards. Storability of dried pulverized kernel samples was carried out by taking desiccated coconut samples as the control under the standard packaging material. Basic quality parameters of charcoal obtained from the gasifier were tested with charcoal made using pit method as the control according to Sri Lankan standards. The basic quality was same in all fresh dried pulverized kernel samples. Aerobic plate counts of fresh dried pulverized kernel samples exceeded the critical limit. During...

E3S web of conferences, 2022

Gasification of untreated and pretreated coconut shell (CS) was carried out in a fixed-bed reactor to assess the effect of temperature (600, 650, 700, 750, and 800 °C) and holding time (30 and 40 min) on gases composition. The untreated CS was first torrefied in a fixed-bed reactor at different temperatures (200-300 °C) and holding times (30 min, 60 min and 90 min). Pretreated CS at the optimal torrefaction temperature (275 °C and 60 min) was used for gasification. Under optimal conditions of 750 °C and 30 min holding time, gasification contributed the most gas production. At this optimum condition, the gas composition of pretreated CS was 35.03 % of CH4, 24.43 % of CO2, and 40.54 % of H2 + CO. Untreated CS contains 37.63 % of CH4, 24.03 % of CO2, and 38.34 % of H2 + CO gases. The production of CH4 gas was higher when untreated CS was used for gasification rather than pretreated CS. Moreover, when untreated CS was used for gasification, the amount of CO2, H2, and CO produced was minimal. Therefore, for high H2 production, pretreatment prior to gasification is appropriate.

International Journal of Technology, 2019

Gasification is one option for producing cleaner fuel from biomass. A gaseous mixture of H2, CO, CH4, and CO2 is produced through the partial oxidation of biomass with a gasifying agent such as air, pure O2, steam, CO2, or a mixture of these. This method is capable of handling a wide range of inhomogeneous biomass (including forest, agricultural, and organic processing residues) and converting them into a homogeneous gas with a considerably higher level of applicability. In this research, the CO2 gasification of hydrothermally treated biomass has been studied using TG-DTA analyzer (Bruker TG DTA 2000SA) apparatus. The biomass treated was a mixture of corn cob and coconut shell (weight ratio of 1:1). This raw biomass was firstly subjected to hydrothermal treatment at three different temperatures (200, 240, and 270°Cdenoted as H-200, H-240, and H-270) using a batch autoclave prior to being gasified by CO2 under atmospheric pressure in the TGA apparatus. The experimental results show that the weight loss of hydrochar was resulted mostly from the process of devolatilization (82.9286.16%). Hydrochar obtained from higher hydrothermal temperatures demonstrated a lower reactivity of gasification, due to the lower amount of moisture and volatile matter. In addition, higher-temperature hydrochar contained lower potassium content and thus shifted the conversion of gasification reaction to a higher temperature.

African Journal of Environmental Science and Technology

The increasing energy demand coupled with the need to reduce greenhouse gas emissions and the threat of exhaustion of oil reserves make us consider a possible recourse to the use of biomass waste as a source of renewable energy. Nowadays, gasification is not yet economically and operationally attractive for the power industry and more research is needed to facilitate the process and improve the desirability of the gasification process. Gasification tests were conducted on five wastes char mainly of agro-sylvo-pastoral residues, in order to study the behaviors of char conversion based on experimental data. Peanut shells, palm shells, cashews nut shells, cashew wood and "kaicedrat" wood char obtained by pyrolysis at 450°C are used. The samples were gasified at three different reaction temperatures (950 to 1050°C) in a fixed bed reactor, using steam or CO 2 as gasification agent and with average fraction of particle size 630 and 3000 µm. The experimental parameters, which affect the char's reactivity, are reviewed similarly to those related to the char and its structural features and operation parameters. Gasification kinetic conversion was studied at different models: the volume reaction model (VRM) and shrinking core model (SCM) in order to interpret the char conversion data. Further, the activation energy and pre-exponential factor were determined using the Arrhenius correlation. The experimental results showed that more syngas ((CO + H 2 )) of high quality were obtained at 1000 to 1050°C during char gasification with steam or CO 2 . The present results showed that temperature has a positive effect on kinetic char conversion. In addition, the low heating values obtained as a function of temperature depend on the nature of sample. For further investigation, it can be shown that the reaction rate is dependent on the char samples. Thus comparing the five biomasses, particular importance about reactivity and lower heating value (LHV) is attached to cashew nut shells, palm shells and peanut shells.

This work aims to compare the behavior of a lab scale downdraft fixed bed gasifier when Colombian Oil Palm Empty bunch fruits (EBF) and Coconut Shells (CSh) are used; temperature profile throughout the reactor is analyzed, syngas CO and CO 2 composition will be characterized and the incidence of biomass proximate and ultimate analysis will be considered. Coconut gasification reached higher temperatures (800 -950°C) than Palm Oil (500-600°C); nevertheless, energy transfer in the bed is better for EBP due to conductivity and porosity. CO 2 and CO levels on syngas are higher for EBP (16% and 12%) in comparison with CSh (9% and 10%), EBP Heating value -20,04 MJ/kg -is 12% higher than CSh -18,70 MJ/kg. Both materials have an interesting potential for heating applications based on syngas utilization.

Disrupted supply of biomass due to seasonal harvesting, climate change, and transportation cost are challenge for continuous biomass gasification operation. Co-gasification is a potential solution for this problem; however, little information is available about co-gasification of different biomass materials. In this study, two tropical plant-based biomass, oil palm fronds (OPF) and coconut shells (CS) were co-gasified in fixed-bed downdraft gasifier at constant airflow rate. The blends of OPF/CS at the ratios of 80:20, 60:40, 40:60, and 20:80 were considered for co-gasification experiments and gasification of pure OPF and CS were carried out at the maximum material size of 10-25 mm. The effect of biomass blending ratio on syngas quality and performance of co-gasification were investigated. The results show that CO, H2, and syngas higher heating value increased by up to 18%, 16%, and 14%, respectively, as compared to gasification of single biomass. The carbon conversion efficiency and cold gas efficiency were also observed to be higher than 95% and 60%, respectively. In many co-gasification cases, quality of syngas and performance of co-gasification were better than using 100% gasification of OPF and CS, which is most important finding of this work. Therefore, co-gasification of the blended feedstock has a significant potential to overcoming the problem of disrupted feedstock supply in gasification.

International Journal of Chemical Engineering, 2015

Effect of KOH, reaction temperature and time, and introduced carbonization step on the amount and composition of syngas as well as porous properties of the carbon products for CO2gasification of coconut shell at low temperatures (300–700°C) was investigated. Results showed that the presence of potassium hydroxide and gasification temperature had a significant effect on the amount and composition of syngas product and facilitated the rate of hydrogen and carbon monoxide formation. It was also found that carbonization step could promote the generation of hydrogen gas as well as increasing the gas heating value per kg of gas. Furthermore, the porosity development of carbon product was found to be influenced by the chemical ratio and gasification temperature. The optimal conditions for achieving high hydrogen composition and specific surface area were to gasify coconut shell under CO2at 600°C for 60 min with carbonization step and with chemical weight ratio of 3.0. This condition gave t...

Biomass energy via gasification is an attractive substitute of fossil fuels. The distribution of biomass on the earth is scattered, so transportation and collection of biomass complicates the supply of biomass especially when the gasification rely on one type of biomass. Therefore, cogasification of different biomass is proposed as a potential solution for interruption-free gasification. Beside, unwanted by-products such as tar that cause blockage in downstream equipment can be minimized through the use of catalyst in gasification to accelerate tar reforming process. In this study, catalytic co-gasification of blended feedstock of 70% wood chips and 30% coconut fronds was carried out in a downdraft gasifier using limestone as primary catalyst. The effects of catalyst loading (0%, 30%, 50%, and 70% w/w) on syngas composition, gas yield, carbon conversion efficiency and heating value of syngas were investigated. The results showed that at 50% biomass to catalyst ratio, maximum H2 content of 11.39%, CO of 17.88%, carbon conversion efficiency of 69.49%, gas yield of 1.68 Nm 3 /kg and higher heating value of syngas 5.11 MJ/Nm 3 were achieved. Higher catalyst loading (70%) blocked the air passage, which caused poor gasification. No more than 50% catalyst suggested for stable co-gasification operation.

Agricultural wastes (biomass) gasifier for electrical power generation in duel fuel mode is a proven technology, yet there is scope for enhancing gasification efficiency at variable conditions. The present system was made with a Ministry of Non-convetional Energy ; MNRE sponsored ,a research gasifier named wbg-15 at "Ankur Scientific and Energy Technology (P) Ltd," Vadodara. The objective of the study is to determine efficiency of biomass burned. The biomass were chopped in 2 to 4 cm length and sun dried to moisture content less than 20 %.Each treatment was replicated tree time. According to the result of the study ,the bulk densities of each biomass was 128 kg / m3 ,97 kg / m3, 273 kg / m3, and 274 kg / m3for coconut husk , stems of cassava , mulberry and cassia stamea respectively. The density of biomass was highest for the cassia stamea and lowest for cassava and coconut ,with an intermediate value for mulberry. Despite these differences in feedback density , there were...