scholarly journals Adiabatic Fixed-Bed Gasification of Colombian Coffee Husk Using Air-Steam Blends for Partial Oxidation

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Javier Bonilla ◽  
Gerardo Gordillo
Keyword(s):  
Partial Oxidation ◽  
Fossil Fuels ◽  
Fixed Bed ◽  
Good Alternative ◽  
Operating Conditions ◽  
Small Scale ◽  
Heating Value ◽  
Coffee Husk ◽  
High Heating Value ◽  
Parametric Studies

The increasing energy consumption, mostly supplied by fossil fuels, has motivated the research and development of alternative fuel technologies to decrease the humanity’s dependence on fossil fuels, which leads to pollution of natural sources. Small-scale biomass gasification, using air-steam blends for partial oxidation, is a good alternative since biomass is a neutral carbon feedstock for sustainable energy generation. This research presents results obtained from an experimental study on coffee husk (CH) gasification, using air-steam blends for partial oxidation in a 10 kW fixed-bed gasifier. Parametric studies on equivalence ratio (ER) (1.53 < ER < 6.11) and steam-fuel (SF) ratio (0.23 < SF < 0.89) were carried out. The results show that increasing both SF and ER results in a syngas rich in CH4 and H2 but poor in CO. Also, decreased SF and ER decrease the peak temperature (Tpeak) at the gasifier combustion zone. The syngas high heating value (HHV) ranged from 3112 kJ/SATPm3 to 5085 kJ/SATPm3 and its maximum value was obtained at SF = 0.87 and ER = 4.09. The dry basis molar concentrations of the species, produced under those operating conditions (1.53 < ER < 6.11 and 0.23 < SF < 0.89), were between 1.12 and 4.1% for CH4, between 7.77 and 13.49% for CO, and between 7.54 and 19.07% for H2. Other species were in trace amount.

Optimization of a Biomass Micro-Gasification Process for the Production of Synthesis Gas From Palm Shell

2015 ◽  
Author(s):  
Luz M. Ahumada ◽  
Arnaldo Verdeza ◽  
Antonio J. Bula
Keyword(s):  
Particle Size ◽  
Fixed Bed ◽  
High Energy ◽  
Operating Conditions ◽  
Air Velocity ◽  
Output Variable ◽  
Heating Value ◽  
Palm Shell ◽  
Gasification Process ◽  
Air Speed

This paper studied, through an experiment design, the significance of particle size, air speed and reactor arrangement for palm shell micro-gasification process in order to optimize the heating value of the syngas obtained. The range of variables was 8 to 13 mm for particle size, 0.8–1.4m/s for air velocity, and updraft or downdraft for the reactor type. It was found that the particle size and air velocity factors were the most significant in the optimization of the output variable, syngas heating value. A heating value of 2.69MJ / Nm3 was obtained using a fixed bed downdraft reactor, with a particle size of 13 mm and 1.4 m/s for air speed; verification of the optimum point of operation under these conditions verified that these operating conditions favor the production of a gas with a high energy value.

scholarly journals A short review on the potential of coffee husk gasification for sustainable energy in Uganda

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1809 ◽  
Author(s):  
Gilbert John Miito ◽  
Noble Banadda
Keyword(s):  
Fossil Fuels ◽  
Short Review ◽  
Energy Market ◽  
Energy Potential ◽  
Coffee Production ◽  
Heating Value ◽  
Coffee Husk ◽  
Gasification Process ◽  
High Dependency ◽  
Coffee Farmers

Agricultural biomass is widely recognized as a clean and renewable energy source, with increasing potential to replace conventional fossil fuels in the energy market. Uganda, like other developing countries, has a high dependency (91%) on wood fuel, leading to environmental degradation. With a coffee production of 233 Metric Tonnes per annum, relating to 46.6 Mega Tonnes of coffee husks from processing, transforming these husks into syngas through gasification can contribute to resolving the existing energy challenges. The objective of this article is to briefly review the energy potential of coffee husks through gasification, and how the gasification process could increase energy recoveries for coffee farmers. Previous  findings indicate that the 46.6 Mega Tonnes per year of coffee husks generated in Uganda, with a heating value of 18.34 MJ/kg, is capable of generating 24 GWh of energy. This will address a 0.7% portion of the energy situation in Uganda, while protecting the environment.

scholarly journals IMPROVE THE PYROLYTIC GAS PRODUCTION BY USING THE CO-PYROLYSIS TECHNIQUE : AN EXPERIMENTAL STUDY

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Abo . Zahra A.I ◽  
M.K. Abd El- Wahab ◽  
M.A. Tawfik
Keyword(s):  
Energy Conversion ◽  
Fluidized Bed ◽  
Conversion Efficiency ◽  
Fixed Bed ◽  
Energy Conversion Efficiency ◽  
Gas Production ◽  
Operating Conditions ◽  
Energy Unit ◽  
Heating Value ◽  
Slow Pyrolysis

The target of the biomass co-pyrolysis is improvingthe heating value of the produced bio-products of a certain type of feedstock, besides disposal of more than one residue in the same time. Thus, this work aims to operate a local fabricated fixed-bed pyrolyzer to improve the pyrolytic gas yield produced by the ground pieces of three biomass residues namely Mango trees Pruning Logs (MPL), Sugarcane bagasse (SB) and Rice straw (RS) using an affordable slow pyrolysis technique. This work was carried out under slow pyrolysis conditions represented in final pyrolysis temperature of 400 °C, vapor residence time of 4 min, heating rate of 0.01-1 °C/s in full absence of oxygen. The pyrolytic gas production was assessed under different feedstock mixing ratios of (1:2:1), (1:1:2) and (2:1:1) as ratio of (RS: SB: MPL), particle lengths of 1-5, 10-15 and 20-25 mm, with and without sandy bed at the bottom of pyrolysis chamber as a fluidized bed. The obtained results showed that, using the fluidized fixed-bed pyrolyzer under slow co-pyrolysis conditions gave the optimum results where in, the pyrolytic gas concentration, gas yield, higher heating value of pyrolytic gasand energy conversion efficiency were 55%, 1.09 Nm3 /kg, 14.97 MJ/Nm3 and 85.43%, respectively, and 53.7%, 1.08 Nm3 /kg, 13.75 MJ/Nm3 ,77.71% in case of using the pyrolyzer without fluidized bed under the same operating conditions. So, the pyrolyzer with fluidized bed achieves an increment in the higher heating value and energy conversion efficiency by about 8.15% and 9.03%, respectivly over the pyrolyzer without fluidized bed.Furthermore, the cost per energy unit of pyrolytic gas produced by the fluidized bed pyrolyzer is lower than the common two fossil gaseous fuels of natural gas and LPG costs by about 28.57% and 80%, respectively.

Char and Tar Production From Dairy Biomass Gasification Using Air-Steam for Partial Oxidation

2011 ◽  
Author(s):  
Gerardo Gordillo ◽  
Kalyan Annamalai
Keyword(s):  
Air Pollution ◽  
Renewable Energy ◽  
Partial Oxidation ◽  
Fossil Fuels ◽  
Renewable Energy Sources ◽  
Fixed Bed ◽  
Dairy Manure ◽  
Energy Sources ◽  
Animal Feeding Operations ◽  
Animal Feeding

The increase in air pollution caused by combustion of fossil fuels demands the exploration of renewable energy sources in order to mitigate the dependence on fossil fuels. Research includes the efforts to partially replace fossil fuels with renewable energy-sources in thermal conversion processes in order to reduce the emission of CO2. The animal wastes can be considered as biomass fuels since their properties are almost similar to ration fed to animals. Concentrated animal feeding operations (CAFOs) such as cattle feedlots and dairies produce a large amount of feedlot manure or feedlot biomass (FB) and dairy manure or dairy biomass (DB), which may lead to land, water, and air pollution if waste handling systems and storage and treatment structures are not properly managed. Both FB and DB are grouped under cattle manure or cattle biomass (CB). The concentrated production of low quality CB at these feeding operations can serve as a good feedstock for locally based gasification for syngas (CO and H2) production and subsequent use in combined heat and power generation. If thermal gasification technology is developed for DB fuels, the environmental impact from both animal feeding operations and fossil-fuels could be mitigated. The current paper presents experimental results obtained from adiabatic fixed-bed gasification of DB using a 10 KW fixed bed counter-flow gasifier and air-steam for partial oxidation. A mass spectrometer (ProLab Thermo ONIX) was used to analyze the gas composition continuously and at real time. The effect of the operating parameters studied, which includes equivalence ratio (1.6 < Φ < 6.4) and steam to fuel (S:F) ratio (0.4 < S:F < 0.8, on the yields of gases, char, and tar are discussed. Also, results from gasification of dairy biomass–ash blend (DB-Ash) and dairy biomass Wyoming coal blend (DB-WYC) is presented for comparison effects. In general, for the set of experiments performed using DB, the gas yield was 1.54 to 5.30 dry tar-free kg of gases per each kg of DAF DB gasified while the char production ranged from 0 to 0.18 kg of char per DAF kg of DB gasified. The average of tar concentration in gases leaving the gasifier was about 80 g/ SATP m3.

Development and Optimization of a Small Scale Pellet Burner

2012 ◽  
Author(s):  
José Carlos Teixeira ◽  
Rui Ferreira ◽  
Eurico A. Seabra ◽  
Manuel Eduardo Ferreira
Keyword(s):  
Fossil Fuels ◽  
High Efficiency ◽  
Practical Interest ◽  
Direct Conversion ◽  
Industrial Applications ◽  
Operating Conditions ◽  
Small Scale ◽  
Cylindrical Shape ◽  
Load Range ◽  
Air Supply

Environmental concerns and the drive to reduce the dependence on petroleum brought the use of renewable energies to the forefront. Biomass appears as a very interesting alternative for direct conversion into heat. In this context, densified forms of biomass such as pellets are of great relevance because of their easy of use, high efficiency and low emissions. The practical interest in pellet combustion has been driven by the domestic heating sector, which favors the characteristics that are intrinsic of this fuel, despite its relatively higher price. However, the growing costs of fossil fuels have extended the interest of pellet fuels into industrial applications, including co-firing in power stations. A fast growing market includes the retrofitting of existing fuel boilers and furnaces with alternative burners that can be fitted into existing combustion systems. Such an approach has proved very attractive due to the low installation cost and the growing existence of fuels produced in the vicinity of the end user. This involves in most cases a custom built application which requires a high level of flexibility to variable operating conditions. This work reports on the development of a 120 kW pellet burner. A prototype of the burner was built that enables the independent control of the air supply into various regions of the combustion chamber and an accurate supply of fuel. The burner was fitted into a testing furnace of cylindrical shape oriented horizontally. Its diameter is 0.5 m and is constructed in a modular fashion with a total length of 2.2 m. All the facility is fully instrumented and includes: temperature data in various locations inside the chamber, flue gases emissions (CO, CO2, NOx) measurements and flow rates. The objective of the test and development is to optimize the combustion over the thermal load range of the facility. The excess air, fuel supply (primary and secondary) and the shape of the furnace grate enable the optimization of the burner with CO emissions of approximately 50 ppm, well below the acceptable limits.

scholarly journals Thermal Deactivation of Rh/α-Al2O3 in the Catalytic Partial Oxidation of Iso-Octane: Effect of Flow Rate

Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 532 ◽  
Author(s):  
Roberto Batista ◽  
Andrea Carrera ◽  
Alessandra Beretta ◽  
Gianpiero Groppi
Keyword(s):  
Partial Oxidation ◽  
Flow Rate ◽  
Catalyst Deactivation ◽  
Hot Spot ◽  
Progressive Increase ◽  
Operating Conditions ◽  
Catalytic Partial Oxidation ◽  
Small Scale ◽  
Α Al2o3 ◽  
Spot Temperature

Catalytic partial oxidation (CPO) of logistic fuels is a promising technology for the small-scale and on-board production of syngas (H2 and CO). Rh coated monoliths can be used as catalysts that, due to Rh high activity, allow the use of reduced reactor volumes (with contact time in the order of milliseconds) and the achievement of high syngas yield. As the CPO process is globally exothermic, it can be operated in adiabatic reactors. The reaction mechanism of the CPO process involves the superposition of exothermic and endothermic reactions at the catalyst inlet. Thus, a hot spot temperature is formed, which may lead to catalyst deactivation via sintering. In this work, the effect of the flow rate on the overall performance of a CPO-reformer has been studied, using iso-octane as model fuel. The focus has been on thermal behavior. The experimental investigation consisted of iC8-CPO tests at varying total flow rates from 5 to 15 NL/min, wherein axially resolved temperature and composition measurements were performed. The increase of flow rate resulted in a progressive increase of the hot spot temperature, with partial loss of activity in the entry zone of the monolith (as evidenced by repeated reference tests of CH4-CPO); conversely, the adiabatic character of the reformer improved. A detailed modelling analysis provided the means for the interpretation of the observed results. The temperature hot spot can be limited by acting on the operating conditions of the process. However, a tradeoff is required between the stability of the catalyst and the achievement of high performances (syngas yield, reactants conversion, and reactor adiabaticity).

Ultrasonic Pelleting and Synchronized Torrefaction of Cellulosic Biomass for Bioenergy Production

2017 ◽  
Author(s):  
Yang Yang ◽  
Nicholas Eisenbarth ◽  
Xiaoxu Song ◽  
Meng Zhang ◽  
Donghai Wang
Keyword(s):  
Power Plants ◽  
Fossil Fuels ◽  
Single Step ◽  
Cellulosic Biomass ◽  
Heating Value ◽  
Step Process ◽  
High Heating Value ◽  
Torrefied Biomass ◽  
High Heating ◽  
The U.S

The U.S. is sustainably producing of over 1 billion dry tons of biomass annually. This amount of biomass is sufficient to produce bioenergy that can replace about 30 percent of the nation’s current annual consumption of conventional fossil fuels. This then gives us the opportunity to turn waste into bioenergy that can assist in meeting the U.S. Renewable Fuel Standard (RFS). Besides being converted into bioethanol through the biochemical platform, biomass can also be utilized solid fuels to generate bioenergy through the thermochemical platform. Co-firing power plants use torrefied biomass pellets combined with coal for electricity generation. A two-step process, torrefaction followed by pelleting, is the prevailing technique that the industry is currently using to produce torrefied biomass pellets. Torrefaction converts biomass into biochar with high heating value, and pelleting densifies torrefied biochar into pellets with high durability and density. For the same purpose, we developed the ultrasonic pelleting and synchronized torrefaction of cellulosic biomass process, which is a single-step process to generate high quality solid fuel pellets with high heating value together with good durability and density. This study reports the first experimental investigation to demonstrate the feasibility of the novel process. Key process parameters have been identified, and their effects on the feasibility of generating quality torrefied biomass pellets are reported. Pellets are evaluated from the aspects of feasibility, durability, heating value, and thermal stability.

scholarly journals Dairy Biomass-Wyoming Coal Blends Fixed Gasification Using Air-Steam for Partial Oxidation

2012 ◽  
Vol 2012 ◽  
pp. 1-7
Author(s):  
Gerardo Gordillo ◽  
Kalyan Annamalai
Keyword(s):  
Fossil Fuels ◽  
Fixed Bed ◽  
Heat Content ◽  
Concentrated Animal Feeding Operations ◽  
Heating Value ◽  
Animal Feeding Operations ◽  
Coal Blend ◽  
Renewable Feedstock ◽  
Lower Heat

Concentrated animal feeding operations such as dairies produce a large amount of manure, termed as dairy biomass (DB), which could serve as renewable feedstock for thermal gasification. DB is a low-quality fuel compared to fossil fuels, and hence the product gases have lower heat content; however, the quality of gases can be improved by blending with coals. This paper deals with air-steam fixed-bed counterflow gasification of dairy biomass-Wyoming coal blend (DBWC). The effects of equivalence ratio (1.6<Φ<6.4) and steam-to-fuel ratio (0.4<S:F<0.8) on peak temperatures, gas composition, gross heating value of the products, and energy recovery are presented. According to experimental results, increasing Φ and (S:F) ratios decreases the peak temperature and increases the H2and CO2production, while CO production decreases. On the other hand, the concentrations of CH4and C2H6were lower compared to those of other gases and almost not affected by Φ.

scholarly journals Properties of chars obtained with pyrolysis of Castanea sativa by product

2017 ◽  
Vol 21 (2) ◽  
pp. 1083-1092 ◽  
Author(s):  
Eylem Pehlivan
Keyword(s):  
Carbon Content ◽  
Surface Area ◽  
Fossil Fuels ◽  
Fixed Bed ◽  
Castanea Sativa ◽  
Fixed Bed Reactor ◽  
Heating Rates ◽  
X Ray ◽  
High Heating Value ◽  
Magnetic Resonance Scanning

The application of biomass derived energy is gaining importance due to the decreasing supply of fossil fuels and growing environmental concerns. This study described the possibility of utilizing Castanea sativa?s by-product as biofuels by producing char via pyrolysis. The process was carried out in a fixed-bed reactor at different heating rates of 10?C, 100?C, and 200?C per minute at temperatures ranging from 400?C to 700?C, and a nitrogen flow rate of 100 cm3 per minute. The produced chars were characterized by proximate and elemental analyses, Brunauer-Emmett-Teller surface area, nuclear magnetic resonance, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray fluorescence analyses. The char yield was found to decrease as both pyrolysis temperature and heating rate increases. The carbon content of char ranged from 68 to 87 wt.%, which correspond to approximately 43% of carbon in the biomass. The char obtained at 700?C had high fixed carbon content (79.90%) as well as high heating value, and hence, it could be used as a solid fuel or as a precursor in the activated carbon production with its 268 m2 per gram surface area.

scholarly journals MODELING OF PARTIAL OXIDATION OF METHANE IN A MEMBRANE REACTOR

2006 ◽  
Vol 5 (1) ◽  
pp. 40 ◽  
Author(s):  
F. A. N. Fernandes ◽  
C. P. Souza ◽  
J. F. Sousa
Keyword(s):  
Partial Oxidation ◽  
Methane Conversion ◽  
Membrane Reactor ◽  
Good Alternative ◽  
Point Of View ◽  
Operating Conditions ◽  
Partial Oxidation Of Methane ◽  
Membrane Reactors ◽  
Operating Pressure ◽  
Oxidation Of Methane

Partial oxidation of methane is one of the most important chemical processes for the production of syngas. In recent years, the abundant availability of natural gas and the increasing demand of hydrogen have led to high interest to further develop this process increasing the yield of syngas. In this work the partial oxidation of methane was studied from a modeling point of view in a membrane reactor and in a conventional reactor. A mathematical model of a membrane reactor used for partial oxidation of methane, assuming steadystate conditions, was developed to simulate and compare the maximum yields and operating conditions in the reactor with that in a conventional reactor. Simulation results show that different parameters affect methane conversion and H /CO ratio, such as temperature, operating conditions, and membrane 2 parameters such as membrane permeance. In a membrane reactor an increase in the operating pressure corresponds to an increase in methane conversion, since allows for a greater partial pressure gradient between the reaction and permeate zone, thus contributing to shift the equilibrium towards the products. As such, the membrane reactors are a good alternative to produce syngas especially for GTL processes. Operating conditions can be set to control the H2/CO ratio to a desired value, and high conversions at mild temperatures can be achieved reducing capital and operational costs.

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