High Calorific Value Research Articles

Analysis of the Energy–Carbon Potential of the Pericarp Cover of Selected Hazelnut Varieties

The research presents weight estimation and analysis of the energy and carbon potential of the pericarp cover of four hazelnut varieties. A technical and elementary biofuel analysis was carried out for the biomass studied, as well as a correlation and principal component analysis to demonstrate the influence of individual characteristics on the parameters achieved. In addition, emission factors and the composition and volume of flue gases from the combustion of the material studied were estimated based on stoichiometric equations. The research showed that the highest calorific value (LHV) was characterised by the pericarp cover of the ‘Olga’ variety (14.86 MJ·kg−1) and the lowest by the ‘Kataloński’ variety (14.60 MJ·kg−1). In the case of exhaust volume, the highest volume was obtained from the ‘Olbrzymi z Halle’ variety (250.06 Nm3·kg−1) and the lowest from the ‘Kataloński’ variety (12.43 Nm3·kg−1). The correlation analysis carried out showed that the HHV and LHV parameters in the covers showed a very strong positive correlation with sulphur content and SO2 emissions, and a moderate correlation with nitrogen content and its associated NOx emissions, indicating their direct influence on the higher calorific value of biomass.

Catalytic pyrolysis of apricot kernel shell over metal supported MCM-41 catalysts obtained by synthesizing sonochemical method

In this study, it is targeted to examine the efficiency of metal supported MCM-41 catalysts on the liquid product yield from pyrolysis process of apricot kernel shell selected as a biomass and to characterize the pyrolysis liquids. In the non-catalytic pyrolysis experiments, the maximum liquid yield is obtained as 21.41 % at 500 °C. At the determined optimum condition, catalytic pyrolysis process of the biomass sample is performed with metal supported MCM-41 catalysts synthesized by sonochemical method (metal: aluminium, cobalt, iron) at different ratios to biomass (1 and 2 wt %). The pyrolysis procedures of apricot kernel shell are carried out in a tubular fixed-bed reactor at different pyrolysis temperatures. The use of catalysts improved both the liquid product (tar) yield and tar quality in respect to the calorific value, the distribution of hydrocarbons and the elimination of oxygenated groups. The results revealed that all metal-supported MCM-41 catalysts, especially the Fe-MCM-41 catalyst ratio of 2, showed an excellent catalytic ability for thermal conversion of biomass. In the catalytic pyrolysis experiments carried out at 500 °C, 75.84 % conversion to liquid and gaseous products was obtained using 2 % Fe-MCM-41 catalyst, and the calorific value of the liquid product obtained was determined as 40.96 MJ/kg. The functional group analyses in the structure of the liquid products are characterized using FT-IR spectroscopy, and the distributions of the aliphatic/aromatic fractions of the liquid products are characterized using GC-MS technique. The H/C ratio of the liquid product obtained from catalytic pyrolysis is between light and heavy petroleum products and also has lower oxygen content and higher calorific value, indicating the potential of metal-supported MCM-41 catalyst for renewable hydrocarbon production from apricot kernel shell.

Assessment and characterization of solid and hazardous waste from inorganic chemical industry: Potential for energy recovery and environmental sustainability

Rapid global urbanization and economic growth have significantly increased solid waste volumes, with hazardous waste posing substantial health and environmental risks. Co-processing strategies for industrial solid and hazardous waste as alternative fuels highlight the importance of integrated waste management for energy and material recovery. This study identifies and characterizes solid and hazardous industrial wastes with high calorific values from various industrial processes at Nirma Industries Limited. Nine types of combustible industrial wastes were analyzed: discarded containers (W1), plastic waste (W2), spent ion exchange resins from RO plants (W3), sludge from effluent treatment in soap plants (W4), glycerine foot from soap plants (W5), rock wool puff material (W6), fiber-reinforced plastic waste (W7), spent activated carbon (W8), and spent cartridges from reverse osmosis plants (W9). Physical characterization, proximate and ultimate analysis, heavy metal concentration evaluation, and thermogravimetric analysis were conducted to assess their properties, revealing high calorific values exceeding 2500 kcal/kg. Notably, W1 and W2 exhibited the highest calorific values (∼10,870 kcal/kg), followed by W6 and W8 (∼6000 kcal/kg) and W9 (∼8727 kcal/kg). Safe heavy metal levels are safe, and high calorific values support the prospects of energy recovery and economic and environmental benefits, reducing landfill reliance and enhancing sustainable waste management.

Properties and combustion characteristics of bioslurry fuels from agricultural waste pyrolysis

ABSTRACT The current research investigates the combustion characteristics of bioslurry fuel derived from the products of agricultural waste pyrolysis. The bioslurry fuel was prepared by mixing biochar and pyrolysis oil. The combustion characteristics of a suspended single droplet of the bioslurry were analysed. The results indicate that an increase in pyrolysis temperature (400–600°C) lead to higher concentrations of fixed carbon (56–60%), increased ash content (16–18%), and higher calorific values (25–32 MJkg−1). As the pyrolysis temperature rises, the biochar surface becomes more porous, lower volatile matter content and particle size. As biochar content increases, the bioslurry’s density, viscosity, and caloric value increase but stability index decreases. Higher biochar content in the bioslurry increases the ignition delay and burnout time while reducing the burning rate. The bioslurry fuel contained 30% biochar achieved a calorific value of 28 MJkg−1 and a viscosity of 600 cP, comparative to conventional fossil fuels. Highlights Up to 30% BC can be added to pyrolysis oil to produce SF. Pyrolysis temperature increased FC, ash, and calorific value of biochar. Biochar surface appears more porous with increasing pyrolysis temperature. Biochar content affects bioslurry combustion characteristics.

Study on the spectral characteristics and chemical structure of Taixi Anthracite

Taixi anthracite is a rare form of coal in both China and the world, characterized by low ash, sulfur, phosphorus, high carbon content, conductivity, and calorific value. Our team employed a solid-phase microwave method [1] to graphitize Taixi anthracite and graft it with natural rubber to create a composite with outstanding properties. However, since the molecular structure of Taixi anthracite was unknown, establishing a molecular model for the reaction becomes crucial for the functionalization of anthracite. In this study, By combining elemental analysis, nuclear magnetic resonance carbon spectroscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, the molecular carbon content of Taixi anthracite is 89 %, the XBP value is 0.37, and the chemical formula of the lowest relative molecular weight of Taixi anthracite is C181H77O4NS0.1. The results of computer simulation show that Taixi anthracite is assembled into coal macromolecular structure by 10 molecular structure units of 5 kinds of coal according to 2:1:2:2:3 ratio, and the geometric optimization, annealing simulation and inverse verification are carried out. The aggregation model is established by using X-ray diffraction data and computer simulation techniques.we innovatively constructed five groups of macromolecular structure units of Taixi anthracite to characterize the results and simulate the minimum energy configuration of single chains and aggregate states. This research provides a molecular-level theoretical basis for the functionalization of Taixi anthracite.

The potential of cashew nut shell waste in charcoal briquettes after producing cashew nut shell liquid through cold extraction

Cashew nut shell liquid (CNSL), extracted without chemicals or high temperatures, primarily contains phenolic compounds and is used in pharmaceuticals and special polymers. This study assesses a cold extraction process for CNSL at press forces of 200, 250, and 275 kg/cm2 and holding times of 1, 2, and 5 min, achieving a maximum yield of 35.98 %, with holding time having minimal impact. The waste from cashew nut shells was carbonized to produce briquettes, enhancing their heating value. Briquettes were made from carbonized cashew nut shells and rice husks in various proportions, using cassava flour as a binder. Analysis of the briquettes' properties showed that the CNS amount significantly influenced calorific value and thermal efficiency, with rice husk charcoal mixtures improving stability and compressive strength. The recommended charcoal briquette from CNS, rice husk and cassava flour which is the ratio 7:3:1 by weight (recipe E), providing high compressive strength and calorific value similar to briquettes made solely from cashew nut shells (recipe A). This research supports converting CNS waste into industrial products and renewable energy.

Effects of High Energy Ball Milling on Particle Size and Density of Amorphous Boron Powder

Amorphous boron powder has high mass and bulk calorific values and is used as a high-energy solid fuel in space propellants. However, the low density and large particle size of the amorphous boron powder prepared by the magnesium thermal reduction method results in its small mass share in the propellant, resulting in its low volumetric calorific value. In this study, amorphous boron powder was prepared by dry and wet ball milling with different rotational velocities and ball milling times and ball-to-matter ratios for planetary ball mills. Optimal process parameters for increasing the loose density and decreasing the particle size of amorphous boron powders have been investigated by unidirectional experiments. The results showed that the ball milling medium was ethanol, the rotational speed was 700 r/min, the ball feed ratio was 12%, and the ball milling time was 12 h. Combined with the ultrasonic-assisted acid leaching, the loose density of amorphous boron powders could be increased from 0.3 g/cm3 to more than 0.5 g/cm3, and the particle size of the powders could be reduced from 4 μm to about 1 μm.

Analyzing the influence of feedstock selection in pyrolysis on aviation gas turbine engines: A study on performance, combustion efficiency, and emission profiles

Commercial aviation is primarily reliant on fossil fuels, yet the depletion of these sources and the consequences of climate change necessitates the exploration of sustainable alternatives. The pyrolysis process offers a viable method for producing biofuels from various feedstocks. This research examines the combustion, emission, and performance characteristics of biofuels derived from agricultural residues, waste tyres, and plastics using pyrolysis. Pyrolysis oils derived from forestry or agricultural products exhibit high viscosity and moisture content, which impairs combustion efficiency and increases carbon monoxide (CO) from 70 % to 187 % and unburned hydrocarbon (UHC) emissions. Conversely, pyrolysis oils from plastics and waste tyres provide stable combustion with carbon monoxide and total hydrocarbon emissions (THC) comparable to those of commercial jet fuel. However, nitrogen oxide (NOX) emissions are significantly elevated from 57 % to 157 %. Engine performance tests demonstrated that forestry pyrolysis oils result in thrust loss due to their high viscosity value (14.3–113 mm2/s) and low calorific value (17.3–31.7 MJ/kg). In contrast, plastic and tyre pyrolysis oil perform similarly to commercial jet fuels but may potentially cause performance loss due to their high aromatic content (>47.67 %). Overall, upgrading the viscosity, moisture, and aromatic content of pyrolysis oils can enhance their suitability as alternative aviation fuels. These improvements could assist the aviation sector in achieving its carbon-neutral goals by making pyrolysis oils competitive with conventional jet fuels.

High‐performance porous transport layers for proton exchange membrane water electrolyzers

AbstractHydrogen is a favored alternative to fossil fuels due to the advantages of cleanliness, zero emissions, and high calorific value. Large‐scale green hydrogen production can be achieved using proton exchange membrane water electrolyzers (PEMWEs) with utilization of renewable energy. The porous transport layer (PTL), positioned between the flow fields and catalyst layers (CLs) in PEMWEs, plays a critical role in facilitating water/gas transport, enabling electrical/thermal conduction, and mechanically supporting CLs and membranes. Superior corrosion resistance is essential as PTL operates in acidic media with oxygen saturation and high working potential. This paper covers the development of high‐performance titanium‐based PTLs for PEMWEs. The heat/electrical conduction and mass transport mechanisms of PTLs and how they affect the overall performances are reviewed. By carefully designing and controlling substrate microstructure, protective coating, and surface modification, the performance of PTL can be regulated and optimized. The two‐phase mass transport characteristics can be enhanced by fine‐tuning the microstructure and surface wettability of PTL. The addition of a microporous top‐layer can effectively improve PTL|CL contact and increase the availability of catalytic sites. The anticorrosion coatings, which are crucial for chemical stability and conductivity of the PTL, are compared and analyzed in terms of composition, fabrication, and performance.

Macauba palm endocarps under compression forces considering the different treatments: A study about physical and mechanical properties for seed extraction

Macauba (Acrocomia aculeata) is a palm tree native to the tropical forests of North America and Brazil, with fruits that hold significant potential across agricultural and industrial sectors, including cosmetics, pharmaceuticals, food, and biofuels. The spherical, drupe-like fruit consists of a fibrous peel (epicarp), pulp (mesocarp), endocarp, and seed. The endocarp, housing the seeds, is a dense, mechanically robust triaxial spheroid with high caloric value. To harness macauba potential on an industrial scale, strategies incorporating high-performance machinery are necessary, replacing rudimentary extraction methods with more rational approaches to crop development. Understanding the physical and mechanical properties of such crops is crucial for designing machines and processes for agricultural product cultivation. This study focuses on the mechanical behavior of the macauba palm endocarp for seed extraction, evaluating its geometric and mechanical properties through compressive stress analysis. Geometric properties such as endocarp characteristics, circularity, sphericity, eccentricity, and surface area were examined, alongside the influence of different endocarp treatments on rupture strengths. Compression tests on macauba fruit endocarps revealed treatment methods (control, 24, 48, and 72-h water immersion, and 10-day sun exposure) influence on mechanical properties at various strain rates (100–600 mm.min-1).Results show the macauba palm endocarp behaves as a spheroid. Immersing macauba endocarps in water increased their rupture strength during compression. However, sun exposure for 10 days rendered the fruit more fragile and less tenacious, reducing rupture force by over 40 % compared to control samples. The Deformity Modulus of macauba fruit endocarp ranged from 30.1 GPa to 53.2 GPa depending on the treatment applied.

Potential of slurry from intensive dairy cattle farms for paulownia and populus trees, as organic fertilizer: i. effect on production

Intensive dairy cattle breeding have a relevant social and economic impact in Portugal, particularly in the northern region. This activity generates a high flow of livestock effluents (slurry), rich in important nutrients for plant growth, which can be introduced into forest production systems. These effluents can provide a good alternative to mineral fertilizers, not only from an economic perspective, but also from the point of view of soil fertility resilience. In the present study, the effect of increasing doses of slurry on tree growth was evaluated in clones of Paulownia and Populus, as they are genotypes that have a high efficiency in the mobilization of soil nutrients and in the capture of CO2 from the atmosphere, as well as high biomass calorific value. To this end, a demonstration field was installed, where the trees were planted with the compasses of: 2.5 x 1.5 m and 2.5 x 0.75 m, respectively for Paulownia and for Populus. In the field, the following treatments were performed: T0 - no fertilization, either mineral or organic; T1 - amount of slurry equivalent to 85 kg of N ha-1; T2 - amount of slurry equivalent to 170 kg of N ha-1; T3 - amount of slurry equivalent to 340 kg of N ha-1, either with or without inoculation prior to transplantation, with mycorrhizal arbuscular fungi and plant growth-promoting bacteria. Results evidenced a positive effect of the slurry application, both in the diameter at breast height and in total stand height, showing its fertilizing potential which should later be assessed on the ability to constitute an alternative or, simply, a complement to mineral fertilization.

Study on the integration of hydrogen in a multi-cylinder low heat rejection diesel engine using a ternary blend

Among alternative fuels, hydrogen (H2) holds significant promise as both a fuel and an energy carrier. It is expected to become a key alternative fuel in the near future to meet stringent pollution standards. H2 is used in internal combustion (IC) engines, gas turbines, and the aerospace industry due to its non-toxic and odorless nature, high calorific value (CV), and wide temperature range of combustibility. Additionally, it is a long-term renewable energy source that produces fewer pollutants. This study explores the impact of different H2 ratios on combustion behavior, engine performance, and emission characteristics in a dual-fuel compression ignition (CI) diesel engine. The current research focuses on the effect of TB of ethanol, Jatropha methyl ester, and diesel with the induction of H2 with different flow rates in diesel engine in dual fuel mode (DFM). The tests were performed at different engine loads, 25%, 50%, 75%, and 100% at a constant engine speed of 2500 rpm. H2 is inducted at different flow rates like 2, 4, and 6 Litres per minute (lpm). Partially stabilized zirconia (PSZ) is used to coat the cylinder head, piston crown, and valves with a thickness of 0.5 mm. The combined effect of TB fuel and H2 in a CI engine improves combustion and engine performance. At full load condition, brake thermal efficiency (BTE) is improved by 11.5% for TB fuel with H2 at 6 lpm, and exhaust gas temperature (EGT) increased by 12.7%. The cylinder pressure (CP) and heat release rate (HRR) are increased by 7.5% and 10.6% at TB fuel with 6 lpm of H2 induction. The utilization of H2 as an alternative energy source has significant consequences for the future of green energy production.

Evaluating the properties that affect the quality of the charcoal product, determining the limits of toxic emissions during combustion, and studying their impact on human health.

This research focuses on examining the potential impact of charcoal briquettes and lumps on human health due to the emissions they release, and verifying their quality standards. Quality assessment was conducted using a device capable of measuring toxic gases to identify contaminants from various sources such as biomass, synthetic resins, coal, metals, and mineral matter. Toxicity assessments were carried out on five types of briquettes and two varieties of lump charcoal. All charcoal samples were subjected to elemental analysis (SEM/EDAX), including the examination of Ca, Al, Cr, V, Cu, Fe, S, Sr, Si, Ba, Pb, P, Mn, Rb, K, Ti, and Zn. The results showed that burning lump charcoal had toxicity indexes ranging from 2.5 to 5, primarily due to NOx emissions. Briquettes, on the other hand, exhibited higher toxicity indices between 3.5 and 6.0, with CO2 being the main contributor to toxicity. The average 24-h CO content of all charcoal samples exceeded the World Health Organization's 24-h Air Quality Guideline of 6.34ppm, with a measurement of 37ppm. The data indicates that most of the products tested did not meet the prevailing quality standard (EN 1860-2:2005 (E) in Appliances, solid fuels and firelighters for barbecuing-Part 2: Barbecue charcoal and barbecue charcoal briquettes-Requirements and test method, 2005), which specifies a maximum of 1% contaminants, with some products containing as much as 21% impurities. The SEM analysis revealed irregularly shaped grains with an uneven distribution of particles, and the average particle size distribution is quite broad at 5μm. Malaysia Charcoal had the highest calorific value at 32.80MJ/Kg, with the value being influenced by the fixed carbon content-higher carbon content resulting in a higher calorific value.

Pyrolysis of wheat straw pellets in a pilot‐scale reactor: Effect of temperature and residence time

AbstractPyrolysis of two types of pellets (T1: 100% wheat straw, and T2: 70% wheat straw; 10% sawdust, 10% biochar, and 10% bentonite clay) was performed in a pilot‐scale reactor under a nitrogen environment at 20°C to 700°C. This was to investigate slow pyrolysis yields and gas composition as a function of temperature and residence time. The experimental data were obtained between 300°C and 600°C, with a residence time of 90 min, a nitrogen flow rate of 50 cm3/min, and a heating rate of 20°C/min. The results indicated that the maximum pyrolysis temperature is 605°C with a residence time of 55 min. The product analysis showed that the proportion of gas was higher than that of biochar and bio‐oil. The conversion efficiency increased with higher temperatures and varied between 66% and 76%. The results showed that carbon dioxide was the main component in the produced gas, and the maximum gas concentration was 63.6% at 300°C for T1. The higher temperature and longer residence time increased the syngas (CO + H2) composition for both T1 and T2 treatments. Nevertheless, the produced biochar had a high carbon content and retained a high calorific value, indicating slow pyrolysis is the ideal utilization route of wheat straw pellet biomass for biochar.

A study on production of hydrogen using Al scrap feedstock.

A sustainable future, concerning the energy transformation of a country, heavily relies on the availability of energy resources, particularly renewables such as solar, wind, hydropower, and clean hydrogen. Among these, hydrogen is the most promising energy source due to its high calorific value, ranging between 120 and 140MJ/kg. It has the potential to lead the market in various industries such as power generation, steel, chemical, petrochemical, and automotive. Significant research has been going on in hydrogen production technologies to reduce costs and improve competitiveness with fossil fuels. One such potential approach includes the use of metal-water reactions, which offer unique opportunities for producing clean hydrogen and other valuable byproducts. However, the quantity of hydrogen produced varies depending on the metal feedstock, type of electrolyte, and the activator or catalyst, used in combination with water. This latest work discusses recent progress on hydrogen production and the effects of variations in different parameters on the process, with a focus on aluminum (Al)-water reactions. Investigations have been conducted and reported on the effect of various activators with different concentrations, the quantity of aluminum scrap feedstock, and the volume of the electrolyte on the kinetics of the metal-water reactions and hydrogen production. Sodium hydroxide (NaOH) was observed to be more effective than potassium hydroxide (KOH) in promoting metal-water reactions. These activator-assisted metal-water reactions help produce clean hydrogen, along with other value-added products such as hydroxides. This work clearly sheds light on the potential utilization of industrial aluminum scrap as feedstock for producing clean hydrogen.

Analisa Kualitas Briket Arang dari Cangkang Kelapa Sawit Dengan Rasio Perekat Amylum dan Ukuran Partikel Terhadap Parameter Produk Briket

One solution to reduce kerosene consumption is by utilizing waste from palm kernel processing to create biochar briquettes. These biochar briquettes are made from palm kernel shells and serve as a dense alternative energy source. Additionally, biomass charcoal can also be used as an alternative fuel. Biomass charcoal has a high calorific value and produces minimal smoke and emissions when burned. Various biomass materials, including palm kernel shells, wood, and coconut husks, can be used. The study aims to determine the burnable surface area of briquettes within a specific time frame. Particle size and adhesive percentage affect the charcoal density on the briquette surface, which, in turn, influences combustion speed. The results indicate that the burnable surface area of the samples is quite small. Furthermore, the study measures the ignition time required for briquettes to burn completely. On average, the samples burn for 90 to 114 minutes. Although there is no significant difference in burn time between mesh sizes 40, 50, and 60, the reference sample burns for up to 3.5 hours.

KARAKTERISTIK LIMBAH BATANG SINGKONG SEBAGAI BIOMASSA CO-FIRING UNTUK PEMBANGKIT LISTRIK

This study evaluates the potential of wet cassava stems, dry cassava stems, and dry cassava stem powder as biomass fuels for co-firing in power plants. The analysis includes proximate testing, calorific value, and ultimate analysis to determine the quality and combustion efficiency of each material. Proximate test results show that dry cassava stems have lower moisture content and higher ash content compared to wet cassava stems, which can affect residue and slagging in power plant equipment. The high volatile matter content and significant increase in fixed carbon from wet to dry conditions indicate a greater extractable energy potential. The gross calorific value shows a significant increase from 2676.11 kcal/kg (AR) to 4929.44 kcal/kg (DAF) for wet cassava stems, and from 3910.64 kcal/kg (AR) to 5046.48 kcal/kg (DAF) for dry cassava stems. Dry cassava stem powder shows a very high calorific value, reaching 4272 kcal/kg (DB). The best ultimate analysis results for cassava stem powder are carbon (C) 48.44%, hydrogen (H) 6.61%, oxygen (O) 43%, sulfur (S) 0.15%, and nitrogen (N) 1.80%.

Enhancing the efficiency of power generation through the utilisation of LNG cold energy by a dual-fluid condensation rankine cycle system

As a clean energy source with high calorific value and low pollution, liquefied natural gas (LNG) has gained much attention and increased fast in the current energy market. It also has considerable cold energy resources that can be used to generate electricity during the regasification process. To fully utilise the cold energy of LNG, a double-Rankine cycle power generation system that incorporates heat exchange between LNG cold energy utilisation and a propane-ethylene cycle working medium is proposed and optimised. The optimisation is based on the Process Integration method, which uses Pinch Analysis to develop a Heat Exchange Network. Upon a specified LNG flow rate of 15.6 kg/s and natural gas delivery pressure of 7.85 MPaG, a retrofit case of the optimised LNG cold energy system generates a power of 1917.21 kW. A 28.6 % increase in power generation efficiency compared with the existing case. The result showed that by employing the Process Integration method, this study maximises the use of LNG cold energy through heat exchange with various working media, effectively addressing power generation efficiency issues. This approach is important in reducing power generation costs, minimising environmental impact, and advancing resource sustainability. Furthermore, it serves as a valuable reference for enhancing power generation efficiency by utilising LNG cold energy.

Thermodynamic Model for Hydrogen Production from Rice Straw Supercritical Water Gasification.

Supercritical water gasification (SCWG) technology is highly promising for its ability to cleanly and efficiently convert biomass to hydrogen. This paper developed a model for the gasification of rice straw in supercritical water (SCW) to predict the direction and limit of the reaction based on the Gibbs free energy minimization principle. The equilibrium distribution of rice straw gasification products was analyzed under a wide range of parameters including temperatures of 400-1200 °C, pressures of 20-50 MPa, and rice straw concentrations of 5-40 wt%. Coke may not be produced due to the excellent properties of supercritical water under thermodynamic constraints. Higher temperatures, lower pressures, and biomass concentrations facilitated the movement of the chemical equilibrium towards hydrogen production. The hydrogen yield was 47.17 mol/kg at a temperature of 650 °C, a pressure of 25 MPa, and a rice straw concentration of 5 wt%. Meanwhile, there is an absorptive process in the rice straw SCWG process for high-calorific value hydrogen production. Energy self-sufficiency of the SCWG process can be maintained by adding small amounts of oxygen (ER < 0.2). This work would be of great value in guiding rice straw SCWG experiments.

Process optimization, exergy analysis, and GHG emissions of ammonia production systems by gasification of high-sulfur petroleum coke with CO2 capture

High-sulfur petroleum coke is commonly used as a fuel because of its high carbon content and calorific value. Direct combustion of high-sulfur petroleum coke has the problem of emitting a lot of CO2 and sulfide. Gasification is an environmentally friendly way to utilize high-sulfur petroleum coke. Therefore, this study first established hydrogen production systems with CO2 capture through high-sulfur petroleum coke gasification. The hydrogen is then reacted with nitrogen from air separation unit for producing ammonia, which is easy to transport and store. After optimizing and analyzing the key parameters of the established models, exergy and life cycle GHG emissions analysis are carried out to evaluate the technical performance and environmental impact. In the system with an 85 % gasification conversion rate of petroleum coke, the ammonia production capacity, exergy efficiency, and GHG emissions are 2300 kmol/h, 45.39 %, and 1468 kg CO2-eq/t NH3. When the conversion rate is elevated by ten percentage points, the ammonia production and exergy efficiency are increased to 2664 kmol/h and 51.95 %, while the GHG emissions are only reduced by 85 kg CO2-eq/t NH3 since most of the CO2 produced by the system is captured. Improving the petroleum coke conversion rate can significantly increase the exergy efficiency of ammonia production system, but has little impact on reducing GHG emissions during the process.