scholarly journals Coal and Biomass Pyrolysis and Gasification – A Review

2018 ◽  
pp. 1-21
Author(s):  
Ngaha Tiedeu William ◽  
Adipah Sylvia
Keyword(s):  
Energy Demand ◽  
Atomic Ratio ◽  
New Techniques ◽  
Heating Value ◽  
Char Gasification ◽  
Gasification Process ◽  
Paper Cover ◽  
Lower Heating Value ◽  
Contrast Analysis ◽  
Lower Heating

In order to advance the research on using new techniques to produce clean and affordable               energy, many gasification experiments have been conducted on different feedstocks and                      the results have been analyzed. Two promising feedstocks which in the future could help to meet the energy demand are coal and biomass. In this paper, we have collected deep insightful information about the processes of coal and biomass gasification and then compared them. The information contained in this paper cover coal and biomass properties, the devolatization process and the reactions occurring during char gasification. The contrast analysis which has been conducted showed for instance that biomass’ higher atomic ratio (H/C, O/C) was the cause of its lower heating value in comparison to coal; carbon conversion values for biomass was significantly higher compared to coal, and during the gasification process, coal feedstock released significantly higher pollutant gases (like H2S) than biomass. In the end, we also presented some innovative technologies that are now developed in the gasification field and which have proven to be highly efficient.

Design of a High Temperature Chamber FED by a Plasma Torch for Thermal Removal of Tars

2009 ◽  
Author(s):  
Alice Fourcault ◽  
Fre´de´ric Marias ◽  
Ulysse Michon
Keyword(s):  
High Temperature ◽  
Thermal Plasma ◽  
Gas Turbines ◽  
Plasma Torch ◽  
Fuel Production ◽  
Heating Value ◽  
Gasification Process ◽  
Incoming Stream ◽  
Lower Heating Value ◽  
Lower Heating

Biomass is one of the most important sources of renewable energy. One aim of Biomass gasification is to convert a solid feedstock into a valuable syngas for electricity or liquid fuel production. Actual industrial auto-thermal gasification processes achieve a production of syngas mainly polluted by products such as dust, nitrogen oxides, sulfur dioxide and tars. Tars remain, one of the main drawbacks in using the gasification process since they are capable of condensing at low temperature. This could lead to fouling, corrosion, attrition and abrasion of downstream devices such as gas turbines or engines. Tars are often removed from the syngas, decreasing the internal energy of the syngas itself. These tars are heavy aromatic hydrocarbons whose treatment remains difficult by thermal, catalytic or even physical methods. They can condense or polymerize into more complex structures, and the mechanisms responsible for their degradation are not completely identified and understood. Turboplasma© is a thermal process, proposed by Europlasma. The main principle of operation relies on the use of thermal plasma for the cracking of tars inside a syngas produced in an auto-thermal gasification step. Basically, it consists of a degradation chamber where the syngas is heated by a plasma torch. The plasma plume provides a high temperature gas (around 5000K) to the system and enables heating of the incoming stream (above 1300K) and also generates high temperature zones (above 1600 K) inside the device. Due to both high temperature and long residence times of the syngas in the vessel, cracking of the tars occurs. Finally, the species released are mainly CO and H2, leading to an increase in the Lower Heating Value of the syngas. The work presented here describes the design of a high temperature gasification system assisted by thermal plasma. It was performed using a CFD computation implemented with a full chemical model for the thermal degradation of tars. The objectives were to understand the aerodynamic behavior of the vessel and to propose enhancement in its design. We present here some results of this study.

scholarly journals Study on Simulation of Biomass Gasification for Syngas Production in a Fixed Bed Reactor

2018 ◽  
pp. 139-149
Author(s):  
Bedewi Bilal ◽  
M. RaviKumar ◽  
Solomon Workneh
Keyword(s):  
Moisture Content ◽  
Biomass Gasification ◽  
Fixed Bed Reactor ◽  
Coffee Bean ◽  
Heating Value ◽  
Reactor Volume ◽  
Gasification Process ◽  
Lower Heating Value ◽  
Gasification Temperature ◽  
Lower Heating

This study was focusing on the simulation of the biomass (coffee bean husk and rice husk) gasification process based on the kinetics of the gasifier and to investigate the produced syngas composition. The ASPEN PLUS simulator was used to investigate the effect of operating parameters on composition of product gas. The gasification process usually begins with the drying process, and then followed by pyrolysis. The pyrolysis process leads to breaking down of the biomass into solid matter, gaseous mixture (mainly CO2, CO, CH4 and H2) and liquid matter. The main focus on biomass gasification process is to efficiently convert the entire char constituent into gaseous product of the syngas by using either steam or CO2. The simulations include; gasification temperature, pressure, reactor volume, Equivalence ratio and moisture content have been investigated. From the result of sensitivity analysis increase the temperature the production of H2 and CO and the increase of moisture content of the biomass the lower heating value of the producer gas decrease. Based on the obtained result the maximum lower heating value of syngas was obtained at the gasification temperature of 8000C, steam to biomass ratio of 0.1, pressure of 1 bar, 0.05 of moisture content and 0.02 m3 of reactor volume.

scholarly journals Combustion Study of Polyoxymethylene Dimethyl Ethers and Diesel Blend Fuels on an Optical Engine

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4608
Author(s):  
Jingjing He ◽  
Hao Chen ◽  
Xin Su ◽  
Bin Xie ◽  
Quanwei Li
Keyword(s):  
Soot Formation ◽  
Comprehensive Evaluation ◽  
Chemical Properties ◽  
Heating Value ◽  
Optical Engine ◽  
Leading Role ◽  
Combustion Duration ◽  
Polyoxymethylene Dimethyl Ethers ◽  
Lower Heating Value ◽  
Lower Heating

Polyoxymethylene dimethyl ethers (PODE) are a newly appeared promising oxygenated alternative that can greatly reduce soot emissions of diesel engines. The combustion characteristics of the PODE and diesel blends (the blending ratios of PODE are 0%, 20%, 50% and 100% by volume, respectively) are investigated based on an optical engine under the injection timings of 6, 9, 12 and 15-degree crank angles before top dead center and injection pressures of 100 MPa, 120 MPa and 140 MPa in this study. The results show that both the ignition delay and combustion duration of the fuels decrease with the increasing of PODE ratio in the blends. However, in the case of the fuel supply of the optical engine being fixed, the heat release rate, cylinder pressure and temperature of the blend fuels decrease with the PODE addition due to the low lower heating value of PODE. The addition of PODE in diesel can significantly reduce the integrated natural flame luminosity and the soot formation under all injection conditions. When the proportion of the PODE addition is 50% and 100%, the chemical properties of the blends play a leading role in soot formation, while the change of the injection conditions have an inconspicuous effect on it. When the proportion of the PODE addition is 20%, the blend shows excellent characteristics in a comprehensive evaluation of combustion and soot reduction.

Biodiesel Effects on Influencing Parameters of Brake Fuel Conversion Efficiency in a Medium Duty Diesel Engine

2010 ◽  
Vol 132 (12) ◽  
Author(s):  
Joshua A. Bittle ◽  
Jesse K. Younger ◽  
Timothy J. Jacobs
Keyword(s):  
Conversion Efficiency ◽  
Energy Content ◽  
Combustion Efficiency ◽  
Operating Conditions ◽  
Biodiesel Fuel ◽  
Mass Energy ◽  
Fuel Conversion ◽  
Heating Value ◽  
Lower Heating Value ◽  
Lower Heating

Biodiesel remains an alternative fuel of interest for use in diesel engines. A common characteristic of biodiesel, relative to petroleum diesel, is a lowered heating value (or per mass energy content of the fuel). For same torque engine comparisons, the lower heating value translates into a higher brake specific fuel consumption (amount of fuel consumed per unit of power produced). The efficiency at which fuel energy converts into work energy, however, may remain unchanged. In this experimental study, evaluating nine unique engine operating conditions, the brake fuel conversion efficiency (an assessor of fuel energy to work energy efficiency) remains unchanged between 100% petroleum diesel fuel and 100% biodiesel fuel (palm olein) at all conditions, except for high load conditions. Several parameters may affect the brake fuel conversion efficiency, including heat loss, mixture properties, pumping work, friction, combustion efficiency, and combustion timing. This article describes a study that evaluates how the aforementioned parameters may change with the use of biodiesel and petroleum diesel, and how these parameters may result in differences in the brake fuel conversion efficiency.

scholarly journals Lower Heating Value of Jet Fuel from Hydrocarbon Class Concentration Data and Thermo-Chemical Reference Data: An Uncertainty Quantification

2021 ◽  
Author(s):  
Randall Boehm ◽  
Zhibin Yang ◽  
David Bell ◽  
John Feldhausen ◽  
Joshua Heyne
Keyword(s):  
Jet Fuel ◽  
Confidence Bands ◽  
Heats Of Formation ◽  
Concentration Data ◽  
Heating Value ◽  
Accuracy And Precision ◽  
Lower Heating Value ◽  
Detailed Assessment ◽  
Value Net ◽  
Lower Heating

A detailed assessment is presented on the calculation and uncertainty of the lower heating value (net heat of combustion) of conventional and sustainable aviation fuels, from hydrocarbon class concentration measurements, reference molecular heats of formation, and the uncertainties of these reference heats of formation. Calculations using this paper’s method and estimations using ASTM D3338 are reported for 17 fuels of diverse compositions and compared against reported ASTM D4809 measurements. All the calculations made by this method and the reported ASTM D4809 measurements agree (i.e., within 95% confidence intervals). The 95% confidence interval of the lower heating value of fuel candidates that are comprised entirely of normal- and iso-alkanes is less than 0.1 MJ/kg by the method described here, while high cyclo-alkane content leads to 95% confidence bands that approach 0.2 MJ/kg. Taking a possible bias into account, the accuracy and precision of the method described in this work could be as high as 0.23 MJ/kg for some samples.

scholarly journals The Technological Investigations Of Manufacturing Of Energy Chips

2015 ◽  
Vol 1 ◽  
pp. 220
Author(s):  
Ziedonis Miklašēvičs
Keyword(s):  
Moisture Content ◽  
Dry Mass ◽  
Quality Parameters ◽  
Heating Value ◽  
Long Term Storage ◽  
Lower Heating Value ◽  
Term Storage ◽  
Lower Heating

The methodology in Latvia forest industry provide to determine the quality of energy chips only in long- term storage places before selling. Due to the lack of hard empirical data about the quality parameters of energy chips in different phases of manufacturing process, this research paper consists of: - the identification and analyses of the factors that influenced the values of energy chips quality features such as: bulk density, moisture content, ash content, higher and lower heating value according to actual moisture content and per dry mass of the chips; - the methodology for determination the quality parameters of energy chips by analysis the wood moisture content and by choice the method of the manufacturing of energy chips.

scholarly journals EXERGY-BASED INVESTIGATION OF A COAL-FIRED ALLAM CYCLE

2019 ◽  
Vol 137 ◽  
pp. 01018 ◽  
Author(s):  
Jing Luo ◽  
Ogechi Emelogu ◽  
Tatiana Morosuk ◽  
George Tsatsaronis
Keyword(s):  
Fossil Fuels ◽  
Coal Gasification ◽  
High Efficiency ◽  
Cycle Performance ◽  
Energetic Efficiency ◽  
Component Level ◽  
Lower Efficiency ◽  
Heating Value ◽  
Lower Heating Value ◽  
Lower Heating

Allam cycle is a novel cycle that capitalizes on the unique thermodynamic properties of supercritical CO2 and the advantages of oxy-combustion for power generation. It is a high-pressure supercritical carbon dioxide cycle designed to combust fossil fuels such as natural gas or syngas (from coal gasification systems) with complete CO2 separation at a high-efficiency and zero atmospheric emissions. This semi-closed cycle produces sequestration-ready/pipeline quality CO2 by-product, and thus eliminates the need for additional CO2-capture system. The Coal-fueled Allam cycle is targeted to deliver between 51-52% net efficiency (lower heating value) for coal gasification. In this study, the expected energetic efficiency is verified by simulating the system in Ebsilon professional software and the result showed that the net efficiency of the simulated coal-fired plant is 30.7%, which is significantly lower than the targeted value. The lower efficiency maybe as a result of the missing heat integration in the system, the high power demand of the oxidant compressor and CO2 compressors. And an exergy analysis based on published cycle data is employed, to investigate the cycle performance, identify the sources of the cycle’s thermodynamic inefficiencies at the component level; a sensitivity analysis is also performed to study the effects of selected thermodynamic parameters on the overall performance of the coal-fired Allam cycle.

Industrial Process Description for the Recovery of Agricultural Water From Digestate

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Halina Pawlak-Kruczek ◽  
Agnieszka Urbanowska ◽  
Weihong Yang ◽  
Gerrit Brem ◽  
Aneta Magdziarz ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Rural Areas ◽  
Reclaimed Water ◽  
Industrial Process ◽  
Hydrothermal Carbonization ◽  
Full Potential ◽  
Agricultural Water ◽  
Heating Value ◽  
Lower Heating Value ◽  
Lower Heating

Abstract Currently, the reclamation and reuse of water have not reached their full potential, although more energy is needed to obtain and transport freshwater and this solution has a more serious environmental impact. Agricultural irrigation is, by far, the largest application of reclaimed water worldwide, so the proposed concept may result in the production of water that can be used, among others, for crop irrigation. This paper describes a novel installation for the recovery of the agricultural water from the digestate, along with the results of initial experiments. Currently, water is wasted, due to evaporation, in anaerobic digestion plants, as the effluent from dewatering of the digestate is discharged into lagoons. Moreover, water that stays within the interstitial space of the digestate is lost in a similar fashion. With increasing scarcity of water in rural areas, such waste should not be neglected. The study indicates that hydrothermal carbonization (HTC) enhances mechanical dewatering of the agricultural digestate and approximately 900 L of water can be recovered from one ton. Dewatered hydrochars had a lower heating value of almost 10 MJ/kg, indicating the possibility of using it as a fuel for the process. The aim of this Design Innovation Paper is to outline the newly developed concept of an installation that could enable recovery of water from, so far, the neglected resource—i.e., digestate from anaerobic digestion plants.

The Ethanol-Water Humidification Process in EvGT Cycles

2004 ◽  
Author(s):  
Marcus Thern ◽  
Torbjo¨rn Lindquist ◽  
Tord Torisson
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Power Production ◽  
Test Facility ◽  
Level Energy ◽  
Water Mixture ◽  
Evaporation Process ◽  
Heating Value ◽  
Lower Heating Value ◽  
Lower Heating

Ethanol from bio-products has become an important fuel for future power production. However, the present production technology is rather expensive. This paper focuses on how to lower the production cost of ethanol extraction from mash, and to use the ethanol as a primary fuel in gas turbines for heat and power production. Today, ethanol is produced during distillation by supplying energy to extract the ethanol from the mash. Using the evaporation process in the evaporative gas turbine to extract the ethanol from the mash before the distillation step, a lot of energy can be saved. In the evaporation process, the ethanol is extracted directly from the mash using energy from low-level energy sources. The evaporation technology is therefore expected to reduce the cost for the ethanol production. Simultaneous heat and mass transfer inside the ethanol humidification tower drives a mixture of ethanol and water into the compressor discharge air. To investigate the evaporation of a binary mixture into air at elevated pressures and temperatures, a test facility was constructed and integrated into the evaporative gas turbine pilot-plant. The concentration of ethanol in the mash is not constant but depends on the sugar content in the feedstock used in the fermentation process. Tests were therefore conducted at different concentrations of ethanol in the ethanol-water mixture. Tests were also performed at different temperature and flow conditions to establish the influence of these parameters on the lower heating value of the produced low calorific gas. It has been shown that this technology extracts about 80% of the ethanol from the mash. It has also been shown that the composition of the resulting gas depends on the temperatures, flow rates and composition of the incoming streams. The tests have shown that the produced gas has a lower heating value between of 1.8 to 3.8 MJ/kg. The produced gas with heating values in the upper range is possible to use as fuel in the gas turbine without any pilot flame. Initial models of the ethanol humidification process have been established and the initial test results have been used for validating developed models.

scholarly journals The Utilization of Plum Stones for Pellet Production and Investigation of Post-Combustion Flue Gas Emissions

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5107 ◽  
Author(s):  
Magdalena Dołżyńska ◽  
Sławomir Obidziński ◽  
Jolanta Piekut ◽  
Güray Yildiz
Keyword(s):  
Food Waste ◽  
Flue Gas ◽  
Energy Systems ◽  
Power Demand ◽  
Wood Pellets ◽  
Heating Value ◽  
Waste Sample ◽  
Lower Heating Value ◽  
Lower Heating ◽  
Ecodesign Directive

Agri-food waste is generated at various food cycle stages and is considered to be a valuable feedstock in energy systems and chemical syntheses. This research identifies the potential and suitability of a representative agri-food waste sample (i.e., plum stones) as a solid fuel. Ground plum stones containing 10, 15, and 20 wt.% of rye bran were subjected to pelletization. The pelletizer was operated at 170, 220, and 270 rpm, and its power demand for the mixture containing 20 wt.% of rye bran was 1.81, 1.89, and 2.21 kW, respectively. Such pellets had the highest quality in terms of their density (814.6 kg·m−3), kinetic durability (87.8%), lower heating value (20.04 MJ·kg−1), and elemental composition (C: 54.1 wt.%; H: 6.4 wt.%; N: 0.73 wt.%; S: 0.103 wt.%; Cl: 0.002 wt.%; O: 38.2 wt.%). Whole plum stones and pellets were subjected to combustion in a 25 kW retort grate boiler in order to determine the changes in the concentrations of NO, SO2, CO, CO2, HCl, and O2 in the post-combustion flue gas. Collected results indicate that plum stone–rye bran pellets can serve as effective substitutes for wood pellets in prosumer installations, meeting the Ecodesign Directive requirements for CO and NO.

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