Increase In Heating Value Research Articles

Simulation of circulating fluidized bed gasification for characteristic study of pakistani coal

Abstract A process model for turbulent pressurized circulating fluidized-bed coal gasifier is created using ASPEN PLUS software. Both hydrodynamic and reaction kinetics parameter are taken into account, whose expressions for fluidized bed are adopted from the literature. Various reactor models available in ASPEN PLUS with calculator as External Block are nested to solve hydrodynamics and kinetics. Multiple operational parameters for a pilot-plant circulating fluidized-bed coal gasifier are used to demonstrate the effects on coal gasification characteristics. This paper presents detailed information regarding the simulation model, including robust analysis of the effect of stoichiometric ratio, steam to coal ratio, gasification temperature and gasification agent temperature. It is observed that, with the increase in the flow rate of air, the components hydrogen, carbon monoxide, carbon dioxide and methane reduce, which causes the Lower Heating Value (LHV) of synthesis gas (Syn. Gas) to decrease by about 29.3%, while increment in the steam flow rate shows a minute increase in heating value of only 0.8%. Stoichiometric ratio has a direct relationship to carbon conversion efficiency and carbon dioxide production. Increasing the steam to coal ratio boosts the production of hydrogen and carbon monoxide, and causes a drop in both carbon dioxide concentration and the conversion efficiency of carbon. High gasifying agent temperature is desired because of high concentration of CO and H2, increasing carbon conversion and LHV. A high gasifying agent temperature is the major factor that affects the coal gasification to enhance H2 and CO production rapidly along with other gasification characteristics.

ICOPE-15-1037 Development of Advanced Integrated coal Gasification Combined Cycle (A-IGCC) Power Generation Systems with a Gas Treating Unit

Advanced Integrated coal Gasification Combined Cycle (A-IGCC) systems have been proposed to obtain higher power generation efficiency than IGCC systems by recycling the exhaust heat from a gas turbine as the heat source of the gasifier. To date, the A-IGCC system including gasification, gas treating including CO_2 capturing and combined cycle power generation units has not been designed. In this study, the performances of A-IGCC systems with these units were evaluated by using process simulator Aspen Plus[○!R] ver. 7.2. Results showed the net thermal efficiencies of A-IGCC models with water gas shift (WGS) and CO_2 capturing units were lower than that of models without these units by 3.5-5.2% because of reduction in gas turbine and steam turbine outputs and additional heat and electricity input to CO_2 capturing unit. Net thermal efficiency of the A-IGCC system with the hot gas desulfurization unit was higher than that with the cold gas desulfurization unit (CGDU) by 1.4-3.1% owing to decrease in heat loss in coolers at CGDU, subsequent increase of heating value of fuel gas into the gas turbine combustors. The CO_2 emission factor can be reduced from 744-769 kg-CO_2/MWh to 117-137 kg-CO_2/MWh by capturing of approximately 85% of CO_2 after WGS.

Hydrogen production using amino acids obtained by protein degradation in waste biomass by combined dark- and photo-fermentation

The biological hydrogen production from amino acids obtained by protein degradation was comprehensively investigated to increase heating value conversion efficiency. The five amino acids (i.e., alanine, serine, aspartic acid, arginine, and leucine) produced limited hydrogen (0.2–16.2mL/g) but abundant soluble metabolic products (40.1–84.0mM) during dark-fermentation. The carbon conversion efficiencies of alanine (85.3%) and serine (94.1%) during dark-fermentation were significantly higher than those of other amino acids. Residual dark-fermentation solutions treated with zeolite for NH4+ removal were inoculated with photosynthetic bacteria to further produce hydrogen during photo-fermentation. The hydrogen yields of alanine and serine through combined dark- and photo-fermentation were 418.6 and 270.2mL/g, respectively. The heating value conversion efficiency of alanine to hydrogen was 25.1%, which was higher than that of serine (21.2%).

On a porous medium combustor for hydrogen flame stabilization and operation

In this study, the characteristics of hydrogen flame stabilization in porous medium combustor were investigated. The flame was observed in a quartz tube. The porous medium was oxide-bonded silicon carbide (OB-SiC) or aluminum oxide (Al2O3) with 60 PPI and 30 PPI pore size distributions. The results indicated that under a low equivalence operation, the flame would transform from surface combustion to interior combustion with an increased heating value. Under a high equivalence ratio, both interior combustion and flashback transition existed at the same time. The thermal conductivity of silicon carbide is higher than that of aluminum oxide. Thus, interior combustion region was more extensive under a low equivalence ratio operation with a high premixed gas velocity. Flashback was apparent for Al2O3 under high an equivalence ratio with low a premixed gas velocity. Consequently, hydrogen flame stability could be controlled by the pore size distribution and thermal conductivity of the porous media, input heating value and input equivalence ratio.

Study on the hydrodeoxygenative upgrading of crude bio-oil produced from woody biomass by fast pyrolysis

Crude bio-oil produced from fast pyrolysis of yellow poplar wood was subjected to HDO (hydrodeoxygenation) for the purpose of reducing water content as well as increasing heating value. HDO was performed in an autoclave reactor at three different reaction factors: temperature (250–370 °C), reaction time (40–120 min), and Pd/C catalyst loading (0–6 wt%) under hydrogen atmosphere. After completion of HDO, gas, char, and two immiscible liquid products (light oil and heavy oil) were obtained. Liquid products were less acidic and contained less water than crude bio-oil. Water content of heavy oil was ranged between 0.4 wt% and 1.9 wt%. Heating values of heavy oil were estimated between 28.7 and 37.4 MJ/kg, which was about twice higher than that of crude bio-oil. Elemental analysis revealed that heavy oil had a lower O/C ratio (0.17–0.36) than crude bio-oil (0.71). H/C ratio of heavy oil decreased from 1.50 to 1.32 with an increase of temperature from 250 °C to 350 °C, respectively.

Experimental study on chemical recuperation using hybrid dielectric barrier discharge-catalytic methane-steam reforming

Hybrid dielectric barrier discharge-catalytic steam reforming is proposed here for use in chemically recuperated gas turbines, so as to be compatible with the low-temperature exhaust heat from turbines. Four different types of reactor were designed for comparison, and extensive experiments were performed to evaluate the exhaust heat recovery in terms of effective carbon recovery rate, methane conversion, fuel heating value increase rate, and total enthalpy increase rate. The effect of methane space velocity and reactor wall temperature on methane conversion have been analyzed. The results showed that, for any reactor, there was an optimum methane space velocity for the most heat recovery. With increasing wall temperatures, the parallel synergistic reforming technology induced more methane conversion than the other reactors. Under the same input power, parallel synergistic reactors could recover more exhaust heat than the sum of catalyst-only and plasma-only reactors, with a relative total enthalpy increase as much as three times the sum of the latter two. Moreover, the parallel synergistic reforming technology resulted in a higher relative total enthalpy increase for reformed gas at low temperatures. These results demonstrate that parallel synergistic reforming technology is a promising technology to significantly recover exhaust heat under different working conditions.

Biogas Filter Based on Local Natural Zeolite Materials

UPT BPPTK LIPI has created a biogas filter tool to improve the purity of methane in the biogas. The device shaped cylindrical tube containing absorbent materials which based on local natural zeolite of Indonesia. The absorbent has been activated and modified with other materials. This absorbtion material has multi-adsorption capacity for almost impurities gas of biogas. The biogas filter increase methane content of biogas for 5-20%. The biogas filter improve the biogas’s performance such as increasing methane contents, increasing heating value, reduction of odors, reduction of corrosion potential, increasing the efficiency and stability of the generator.

In-situ catalytic conversion of tar using rice husk char-supported nickel-iron catalysts for biomass pyrolysis/gasification

This paper aims to propose an effective tar conversion approach during biomass pyrolysis via in-situ dry reforming over rice husk (RH) char and char-supported Ni-Fe catalysts. Utilizing high pyrolysis temperature, tar from biomass pyrolysis could be removed effectively in the gasifier by mixing with the char-supported catalysts, simplifying the follow-up tar removal process. Under the optimized conditions, the conversion efficiencies of condensable tar can reach about 92.3% and 93% using Ni-Fe char (without calcination) and Ni char (with calcination), respectively. It is noteworthy that the condensable tar could be catalytically transformed into the non-condensable tar or small molecule gases resulting in the heating value increase of gaseous products to benefit of the power generation systems. Compared with the other catalysts preparation methods, Ni–Fe char exhibited more advantages of convenient and energy-saving. In the presence of catalysts, the concentration of CO2 (vol.%) was reduced slightly, while the CO concentration (vol.%) increased greatly because of dry reforming. Due to carbon loss, parts of RH char-supported catalysts (C-SiO2 catalysts) could be converted into SiO2-based catalysts because of high-content amorphous nano-sized SiO2 in RH char. In addition, partial metal oxides or ions via carbon (i.e., biochar) and gas (i.e., H2, CO) in-situ reduction were transformed into metallic states contributing to the enhancement of tar conversion. Therefore, RH char plays two significant roles during the process of biomass pyrolysis. On one hand, it works as an intermediate reductant to reduce the metal oxides and CO2; on the other hand, it can be considered as an adsorptive-support to adsorb metal ions and tar. After that, the char-supported catalysts could be used for tar conversion. In particular, since the metal catalysts still remain in the solid residues, the pyrolysis char could be regenerated via thermal regeneration using waste heat or gasified into syngas directly.

Photochemical and acoustic interactions of biochar with CO2 and H2O: Applications in power generation and CO2 capture

A critical literature review suggests that carbonaceous compounds react with (CO2 +H2O) mixture through thermal, photochemical, and sonochemical/sonophysical routes. A biochar was selected for studying these effects at 60°C and 1 atm for its potential benefits on power generation and CO2 capture. All treatments remove sizable minerals (K, Na, and Si) detrimental in power generation, and introduce carbon (up to 16% of original carbon in biochar) into the biochar matrix. Most treatments show increased hydrogen (up to 24%). Treatments lead to notable increased heating value of biochar (up to 50%). Treated biochars show increase (up to 19 fold) in internal surface area. The ultrasound energy output is a fraction of the increased heating value. Thus, pretreatment is potentially attractive for increasing the energy efficiency in combustion and gasification. Moreover, better understandings of the salient reactions of these processes will be advantageous for the development of advanced adsorbents for CO2 capture. © 2014 American Institute of Chemical Engineers AIChE J, 60: 1054–1065, 2014

MUTU BIOPELET DARI CAMPURAN ARANG DAN SABUT CANGKANG SAWIT

Biomass pellet (biopellet) is a biomass-based solid fuel with tubular solid form which is one of alternative energy for rural community. The abundance of palm shell and palm fiber is a potential source of biomass that can be converted into biopellet. Pelletization can improve the quality and burning characteristics of biomass. The objectives of this research were to study the utilization of palm shell and fiber into biopellet production and to assess the effect of addition of palm shell charcoal and palm fiber. The percentages of palm shell charcoal and palm fiber were 0%, 10%, and 20%. Carbonization process was done by using kiln for ±4.5 hours at 450○C. Densification process was done by using pellet mill whose the capacity of 10 kg/hour with a dies diameter of 15 mm and at temperature of 250○C for 2 minutes of pressure time. The research was started with an analysis of physic-chemical properties of the raw material and then followed by analysis of combustion characteristics. Based on the physic-chemical properties and the combustion characteristics, biopellet of palm shell that contained 80% of palm shell and 20% of palm shell charcoal gave the best quality. It had moisture content of 0.47%, ash content of 9.83%, volatile substances of 55.34%, fixed carbon of 34.84%, heating value of 5,265.92 kcal/kg, bulk density of 1,260.30 kg/m3, and pressure strength of 82.09 kg/cm2. The consumption rate was 1.39 kg/hour and the combustion efficiency was 11.59%. The production of palm shell biopellet on a laboratory scale produced yield of 11.54%. Biopellet increased heating value of palm shell for 15.55%. Keywords: biopellet, palm shell, palm fiber, charcoal, carbonization

Characteristics of Torrefaction with Water Hyacinth

oC) and three time settings (1, 2, 3 h) using small electric heaters (11.3l of holding volume). This study investigated the heating values with the washing process and process factors influenced the torrefaction. In addition, this study compared the heating values in washed and unwashed samples and suggested the optimal conditions for increasing heating value. Results: Torrefaction increased the heating value by 8.18 ~ 30.04%. Comparing heating values of each condition, the optimal temperature for torrefaction was 300 o C and holding time was 1 hour. The washing process increased the heating value by 19 ~ 27%. The heating value of the sample treated at 300 o C for three hours was 4310.80 kcal/kg, which was greater than the first class wood pellet of 4300 kcal/kg. Conclusions: This study proved that the torrefaction and washing process inc reased the heating value of water hyacinth. Therefore, water hyacinth is expected to be an eco-friendly biomass which substitutes for wood pellet.

Dry torrefaction of biomass – Torrefied products and torrefaction kinetics using the distributed activation energy model

Torrefaction is a thermal treatment applied to improve biomass properties for long-term storage and thermochemical conversion of wood. The torrefaction kinetic behavior of two woody biomass samples (aspen and birch) and their individual constituents (cellulose, xylan -hemicellulose proxy- and lignin) was studied in detail. The materials were torrefied in a fixed-bed reactor up to 280°C and were characterized after 15min and 60min treatments in terms of their energy density, energy yield, H, O and C contents, humidity uptake and FTIR vibrational spectra. Regardless of mildness (240°C) or severity (280°C) of torrefaction, hemicellulose was the most reactive. Compared to torrefied cellulose, lignin exhibited considerable activity and increased heating value under severe torrefaction (280°C). Likewise, the increase in heating value of torrefied cellulose was less significant than that of lignin due to cellulose energy loss because of production of tar compounds. The release of volatiles versus time for cellulose, xylan and lignin torrefaction reactions measured using a thermogravimetric method was also modeled for each lump by means of the distributed activation energy model and a three-parameter log-normal distribution function. The model was found to fit the experimental data for xylan and lignin torrefaction while it showed slight under-prediction in the case of cellulose torrefaction. The distributed activation energy models developed for the individual lumps were combined into a meta-model to apprehend the torrefaction kinetics of actual (aspen and birch) woody biomass by assuming parallel and independent involvement of their three constituents present under various compositions. The model was found to represent with very good agreement the experimental data of aspen and birch torrefaction.

An Experimental Study on Binderless Briquetting of Low‐Rank Coals

AbstractThe potential of binderless briquetting as a means of transforming low‐rank coals into low moisture high grade solid fuel products has been studied. Using two dried low‐rank coals, binderless briquettes with high mechanical strength have been successfully produced through mechanical compression. An increase in heating value was achieved as a result of moisture reduction in the briquettes compared to as‐received coals. The residue moisture content in the briquettes had a predominant effect on briquetting characteristics and there existed an optimum moisture content for the maximum briquettes strength. The chemical structure and wettability of binderless briquettes were analyzed using FTIR and contact angle measurement. The results showed that hydrophobicity and chemical structure significantly affected the briquette properties.

The intermediate pyrolysis and catalytic steam reforming of Brewers spent grain

Brewers spent grain (BSG) is a widely available feedstock representing approximately 85% of the total by-products generated in the brewing industry. This is currently either disposed of to landfill or used as cattle feed due to its high protein content. BSG has received little or no attention as a potential energy resource, but increasing disposal costs and environmental constraints are now prompting the consideration of this. One possibility for the utilisation of BSG for energy is via intermediate pyrolysis to produce gases, vapours and chars. Intermediate pyrolysis is characterised by indirect heating in the absence of oxygen for short solids residence times of a few minutes, at temperatures of 350–450°C. In the present work BSG has been characterised by chemical, proximate, ultimate and thermo-gravimetric analysis. Intermediate pyrolysis of BSG at 450°C was carried out using a twin coaxial screw reactor known as Pyroformer to give yields of char 29%, 51% of bio-oil and 19% of permanent gases. The bio-oil liquid was found to separate in to an aqueous phase and organic phase. The organic phase contained viscous compounds that could age over time leading to solid tars that can present problems in CHP application. The quality of the pyrolysis vapour products before quenching can be upgraded to achieve much improved suitability as a fuel by downstream catalytic reforming. A Bench Scale batch pyrolysis reactor has then been used to pyrolyse small samples of BSG under a range of conditions of heating rate and temperature simulating the Pyroformer. A small catalytic reformer has been added downstream of the reactor in which the pyrolysis vapours can be further cracked and reformed. A commercial reforming nickel catalyst was used at 500, 750 and 850°C at a space velocity about 10,000L/h with and without the addition of steam. Results are presented for the properties of BSG, and the products of the pyrolysis process both with and without catalytic post-processing. Results indicate that catalytic reforming produced a significant increase in permanent gases mainly (H2 and CO) with H2 content exceeding 50vol% at higher reforming temperatures. Bio-oil yield decreased significantly as reforming temperature increased with char remaining the same as pyrolysis condition remained unchanged. The process shows an increase in heating value for the product gas ranging between 10.8–25.2MJ/m3 as reforming temperature increased.

Performance and fuel conversion efficiency of a spark ignition engine fueled with iso-butanol

Alcohols are increasingly used as fuels for spark ignition engines. While ethanol is most commonly used, long chain alcohols such as butanol feature several advantages like increased heating value and reduced corrosive action. This study investigated the effect of fueling a port injection engine with iso-butanol, as compared to gasoline operation. Performance levels were maintained within the same limits as with the fossil fuel without modifications to any engine component. An additional electronic module was used for increasing fuel flow by extending the injection time. Fuel conversion efficiency decreased when the engine was fueled with iso-butanol by up to 9% at full load and by up to 11% at part load, calculated as relative values. Incomplete fuel evaporation was identified as the factor most likely to cause the drop in engine efficiency.

Copyrolysis of block polypropylene with waste wood chip

In this study, the copyrolysis of waste wood chip (WC) and block polypropylene (PP) was studied to investigate how the characteristics of bio-oils are affected by copyrolysis. The thermogravimetric analysis performed with a temperature rise of 20 °C/min, from room temperature to 600 °C, showed that the decomposition temperature of PP was a little higher via copyrolysis than the single-component pyrolysis. This result suggests that the characteristics of the pyrolysis of PP were affected by the pyrolysis products of WC. The Py-GC/MS analysis of the copyrolysis products detected some new compounds that had not been detected in the single-component pyrolysis products, indicating interactions between the products of WC and PP pyrolyses. The results of the experiments using a fixed bed reactor showed improved properties of the bio-oil obtained from the copyrolysis compared to those of the bio-oil obtained from the single-component pyrolysis: increased carbon and hydrogen contents, decreased water content and a significantly increased heating value.

Nickel-catalyzed carbonization of wood for coproduction of functional carbon and fluid fuels II: improved fuel quality of oil fraction and increased heating value of gas fraction

The yields and properties of oil and gas fractions coproduced during carbonization of larch wood loaded with Ni 2%, Ni 2%+Ca 1%, and Ni 4% and without catalyst (None) at 700°–900°C were examined to clarify the catalytic effect in terms of conversion into fluid fuels. The net calorific value of oil occurred mainly below 500°C and increased in the order None < Ni 2% < Ni 4% < Ni 2%+Ca 1%, while the yield decreased in this order. The same order held for the production of gases enriched with hydrogen at 500°–700°C. Even above 800°C, markedly promoted evolution of hydrogen took place for all catalyst systems. These observations confirmed the effectiveness of nickel-catalyzed carbonization at 900°C, particularly Ni 2%+Ca 1%, for both upgrading of oil and gaseous fractions, although the quality of oil was not satisfactory. The catalysis of nickel with and without calcium is discussed on the basis of the modified Broid-Shafizadeh scheme, and the scheme was altered to adapt to the high temperature region where oil was no longer produced.

Production of bio‐crude from forestry waste by hydro‐liquefaction in sub‐/super‐critical methanol

AbstractHydro‐liquefaction of a woody biomass (birch powder) in sub‐/super‐critical methanol without and with catalysts was investigated with an autoclave reactor at temperatures of 473–673 K and an initial pressure of hydrogen varying from 2.0 to 10.0 MPa. The liquid products were separated into water soluble oil and heavy oil (as bio‐crude) by extraction with water and acetone. Without catalyst, the yields of heavy oil and water soluble oil were in the ranges of 2.4–25.5 wt % and 1.2–17.0 wt %, respectively, depending strongly on reaction temperature, reaction time, and initial pressure of hydrogen. The optimum temperature for the production of heavy oil and water soluble oil was found to be at around 623 K, whereas a longer residence time and a lower initial H2 pressure were found to be favorite conditions for the oil production. Addition of a basic catalyst, such as NaOH, K2CO3, and Rb2CO3, could significantly promote biomass conversion and increase yields of oily products in the treatments at temperatures less than 573 K. The yield of heavy oil attained about 30 wt % for the liquefaction operation in the presence of 5 wt % Rb2CO3 at 573 K and 2 MPa of H2 for 60 min. The obtained heavy oil products consisted of a high concentration of phenol derivatives, esters, and benzene derivatives, and they also contained a higher concentration of carbon, a much lower concentration of oxygen, and a significantly increased heating value (&gt;30 MJ/kg) when compared with the raw woody biomass. © 2009 American Institute of Chemical Engineers AIChE J, 2009

Flash co-pyrolysis of biomass with polyhydroxybutyrate: Part 1. Influence on bio-oil yield, water content, heating value and the production of chemicals

Bio-oil obtained via flash pyrolysis shows potential to be applied as a renewable fuel. However, bio-oil often contains high amounts of water, which is a major drawback for its application. The influence of a biopolymer – polyhydroxybutyrate (PHB) on the pyrolysis of willow is investigated using a semi-continuous home-built pyrolysis reactor. The flash co-pyrolysis of willow/PHB blends (w/w ratio 7:1, 3:1, 2:1 and 1:1) clearly shows particular merits: a synergetic increase in pyrolysis yield, a synergetic reduction of the water content in bio-oil, an increase in heating value, and a production of easily separable chemicals. The occurrence of synergetic interactions is observed based on a comparison between the actual pyrolysis results of the willow/PHB blends, the theoretical pyrolysis results calculated from the reference pyrolysis experiments (pure willow and pure PHB) and their respective w/w ratio. The co-pyrolysis of 1:1 willow/PHB shows the best overall results.

Physical and Chemical Properties of GTL−Diesel Fuel Blends and Their Effects on Performance and Emissions of a Multicylinder DI Compression Ignition Engine

An analysis of physical and chemical properties of Fischer−Tropsch fuel gas-to-liquids (GTL) blends with a conventional diesel was conducted. Then, engine performance, combustion, and emission investigations were performed to better understand the differences in regulated emissions between diesel, GTL, and their blends using a six-cylinder turbocharged direct-injection compression ignition (DICI) engine at different load-speed conditions and pump timings. Most of the properties of blended fuels have a good linear relation with the GTL volume fraction in the blends. Density, sulfur, polyaromatics, and total aromatics of blends decrease, while the cetane number and lower heating value increase as the GTL fraction increases. Both the maximum combustion pressure and peak value of heat release rate for neat GTL are slightly lower, and the locations of the two peaks are slightly retarded versus those of the diesel. GTL blends, especially neat GTL, show improvements in fuel economy and thermal efficiency. GTL bl...