Eggshell Catalyst Research Articles

Performance of PdAu/Al2O3 egg-shell catalyst with isolated Pd1 sites for selective hydrogenation of acetylene

A herein proposed PdAu/Al2O3 egg-shell catalyst for selective acetylene hydrogenation combines two factors to provide perfect performance: isolation of Pd1 active sites by Au and an egg-shell distribution of the active phase across the catalyst pellets. The PdAu/Al2O3 catalyst exhibits high acetylene hydrogenation activity at the level of Pd-catalysts and high intrinsic ethylene selectivity of Au-catalysts.

Comparative analysis of hydrogen production from ammonia decomposition in membrane and packed bed reactors using diluted NH3 streams

Ammonia decomposition is a key technology for its use as a hydrogen carrier and in the recovery of H2 from waste streams containing ammonia. The coupling of the catalytic decomposition of ammonia with an H2 permeoselective membrane improves the process by mitigating thermodynamic constraints and producing a flux of high-purity hydrogen, not requiring further separation/purification. In this study, we compare the behaviour of an eggshell catalyst 1.3 wt % Ru/Al2O3 catalyst in a packed bed reactor (PBR) and a packed bed membrane reactor (PBMR) using an ultrathin Pd membrane (3.4 μm). Tests were made at 11 bar(a) with a weight hourly space velocity of NH3 in the 0.560–1.68 Lꞏg−1ꞏh−1 range and temperatures of 350–400 °C, e.g. milder conditions than the conventional ammonia cracking catalysts. Under optimised conditions (0.56 Lꞏg−1ꞏh−1, 400 °C, sweep gas flow 0.55 L min−1), the PBMR shows excellent performance, achieving NH3 conversion, H2 productivity and recovery factor of 99%, 47 mmolH2·gRu−1·min−1, and 94.9%, respectively. PBMR increases by ∼50% the conversion rate compared to PBR. Without a sweep gas, PBMR performances are lower, even still higher than in PBR. For the first time, superior or comparable performance was demonstrated compared to similar systems using pure ammonia in terms of conversion, hydrogen recovery, H2 productivity, and Ru utilisation. These results can be further enhanced with vacuum systems to convert diluted ammonia streams into high-purity hydrogen for small-scale distributed systems and can be extended to other reactions.

Production of green diesel from waste cooking oil via catalytic deoxygenation reaction using metal doped eggshell catalyst

Abstract Green diesel production via catalytic deoxygenation of waste cooking oil (WCO) over metal doped eggshell catalyst was investigated in this work. The catalyst was prepared through liquid-liquid precipitation of 5 transition metal solutions and ground eggshell (ES) as the catalyst support. The prepared catalyst, Fe-ES, Cu-ES, Co-ES, Zn-ES, and Ni-ES were characterized using BET surface area and Scanning Electron Microscopy (SEM) analysis. BET surface area data and SEM images of the catalyst shows a promising catalyst physical properties that tailor to the deoxygenation reaction. Gas Chromatography Mass Spectrometry (GCMS) was used to determine the hydrocarbon composition of the oil yield product from the reaction. The reaction also produces gas, soap and liquid acid phase while the remaining unreacted WCO becomes coke. The percentage of all products and coke were calculated using mass balance. Deoxygenation of WCO with Ni-ES catalyst produced highest oil yield at 61.6% with the hydrocarbon content of 56.11%. Ni-ES also produced 22.9% coke; the least percentage compared to other catalyst. The findings proved that Ni-ES catalyst exhibited the highest conversion of WCO into gas and liquid product with a greater yield of oil and minimal coke formation. These findings demonstrate the feasibility and practicality of using eggshell catalysts as substitutes for commercial catalysts in green diesel production.

Eggshell catalysed rubber aggregates for the sustainable green mortar constructions

Sustainability growth in the infrastructure field demands the need for environmentally friendly construction without compromising its structural properties. In this paper, a durable rubberized geopolymer mortar was developed by using the eggshell catalyzation technique. In order to enhance the interfacial bonding of rubber aggregates with the potassium-based geopolymer mortar, the eggshell catalyst was employed as a natural surface modifier. The developed eggshell catalyzed rubber was used to replace 5% by weight of the fine aggregate system and the sustainability of the rubberized geopolymer mortars was studied by assessing the strength and durability characteristics. From the results, it was inferred that the eggshell catalyst transformed the rubber surface into highly hydrophilic and showed a water contact angle of 10°. The trans-esterification process induced by the eggshell-catalyzed rubber aggregates resulted in 10% improved workability and 98.8% recovery in compressive strength of the rubberized geopolymer mortar. Also, due to the formation of secondary gels around the eggshell-catalyzed rubber, the geopolymer mortar becomes denser which prevents the intrusion of foreign ions and showed a 27.9% change in mass under sulphate attack and 33.86 MPa residual compressive strength after 90 days of acid immersion. This attributed the rubberized geopolymer mortar with eggshell catalyzation process to maintain its structural integrity even in the aggressive chemical environment for the feasible applications of deck slab, piers, underground pipe construction, etc.

Production Biodiesel from Vegetable Oils Using Duck Egg Shell Catalyst

Population growth causes energy needs to increase. Energy needs in Indonesia currently still depend on petroleum fuel. This research aims to determine the effect of the concentration of adding catalyst from egg shells on the production of biodiesel and determine the quality of biodiesel produced using egg shell catalyst. This research was carried out in 2 stages, namely catalyst preparation and the biodiesel manufacturing process. In catalyst preparation, egg shells that have been washed clean are then dried and crushed, then calcined using a furnace at a temperature of 1000°C for 7 hours. Next is the stage of making biodiesel using the conventional method which is carried out with variations in catalyst concentration of 1%, 2%, 3%, 4% and 5% (w/w). The research results showed that the best product yield was 78% at a concentration of 3% in 2 hours with a specific gravity of 0.889 gr/cm3 and a viscosity of 5.74 cSt.

Catalytic conversion of biomass-plastic blend to high-quality bio-oil via co-pyrolysis using chicken eggshell waste as deoxygenation catalyst: A feasibility study

Energy shortages and reliance on fossil fuels have led to the discovery of new technologies to reduce the environmental impact by taking advantage of excess plastic and turning them into usable alternative fuels using the pyrolysis method. However, the oil produced contains highly oxygenated compounds, which are considered a downside to the fuel characteristics, along with a low by-product yield. Therefore, feasibility study of calcined eggshells as a deoxygenation catalyst in the co-pyrolysis of empty fruit bunch (EFB)/high-density polyethene (HDPE) blend and compare it quantitatively and qualitatively with bio-oil produced using a commercial zeolite-based catalyst, ZSM-5 and Fluid Catalytic Cracking (FCC) at 500 °C operating temperature, 10 ft3/min N2 flow rate, 10 wt% catalyst loading, 1:1 HDPE:EFB ratio and 75 g feedstock with 60 min operating time in a stainless-steel fluidised bed reactor. Natural and calcined chicken eggshells were characterised using TGA/DTG, while the bio-oil produced was characterised using GC–MS. By using FCC catalyst, the highest oil yield (13.2 wt%) with high oxygenated compounds was obtained. The oil with the highest hydrocarbon yield (61.62 %) and lowest oxygenated compound content (38.38 %) was obtained using a calcined chicken eggshell (CES) catalyst. Calcined chicken eggshell (CES) catalysts showed better performance than commercial catalyst in terms of the quality and average yield of bio-oil produced. This study confirmed that the presence of a catalyst in the co-pyrolysis of EFB and HDPE can improve the yield of bio-oil and enhance its quality.

Cost, Emission, and Thermo-Physical Determination of Heterogeneous Biodiesel from Palm Kernel Shell Oil: Optimization of Tropical Egg Shell Catalyst

The advantages of reusability, lower cost, and environmentally friendly operation have made the heterogeneous catalyzed methylic process a preferable alternative to the homogeneously catalyzed protocol. The optimal production yield of palm kernel shell oil (PKSO) methyl ester (PKSOME) was modeled using Response Surface Methodology (RSM). The cost of PKSOME was determined, and the synthesized PKSOME was blended with diesel fuel with various volume ratios. Several analyses were done, including thermophysical properties using ASTM test methods, density and viscosity, fire point and flash point, aniline point, and acid value. Emission characteristics such as exhaust smoke, carbon monoxide, and carbon dioxide were measured using an IC engine. The use of waste eggshells for heterogeneously catalyzed biodiesel from underutilized PKSO for green diesel can reduce production costs even further. The green biodiesel model and TP correlations have applications in the biodiesel and aviation industries.

Can waste eggshell replace commercial zeolites as catalyst for bio-oil production?

The utilisation of calcium oxide (CaO) from waste chicken eggshells, fishbone, and dolomite as a catalyst in the co-pyrolysis of empty fruit bunch (EFB) and high-density polyethene plastic (HDPE) was investigated and compared with existing commercial zeolite catalysts (HZSM-5, NaY, and FCC). In-situ catalytic co-pyrolysis of EFB-HDPE was performed for each CaO and zeolite-based catalyst. Gas Chromatography-Mass Spectrometry (GC-MS) was used to analyse the hydrocarbon content of the bio-oil produced by pyrolysis. The highest hydrocarbon content (61.62%) was obtained from the calcined eggshell (CES) catalyst and was comparable to that of the commercial zeolite catalyst, HZSM-5, with a hydrocarbon content of 53.53%. Brunauer–Emmett–Teller (BET) analysis, Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDX) analysis, and Particle Size Analysis (PSA) have proven the viability of CaO-based catalysts in the co-pyrolysis process for bio-oil production via fast pyrolysis. The CES achieved the desired pore diameter (175.15 nm) which was exhibited in the morphology analysis (SEM) and exhibited a uniform arrangement of calcium oxide particles and a porous structure. This finding provides fundamental insight into CaO from organic waste as a suitable alternative to zeolite catalysts in the co-pyrolysis of organic and inorganic feedstocks.

Experimental investigation and 2D mathematical modelling of copper foams packed with Rh-Al2O3 catalysts for the intensification of methane steam reforming

Efficient heat transfer is a crucial factor in the design of compact methane steam reformers for delocalized hydrogen production. The use of copper packed foams was proposed few years ago by our group to strongly intensify heat transfer in these systems, allowing the design of small-scale units with minimal radial temperature gradients. In this study, a new experimental campaign was performed to demonstrate the concept potential under industrially relevant heat fluxes and to establish an experimental foundation for validating a 2D mathematical model of the process. Copper open-cell foams were packed with a Rh/Al2O3 egg-shell catalyst and loaded into a 29.5 mm diameter tubular reactor, which was heated using a lab-scale oven. By leveraging the combined benefits of enhanced heat transfer, granted by the copper foam, and the high activity of the Rh-based eggshell catalyst, experiments were successfully performed at gas hourly space velocities (GHSV) ranging from 10 to 30 Nm3/h/kgcat, with heat duties of up to 9 MW/m3. These experiments lead to a methane conversion close to thermodynamic equilibrium while maintaining limited radial gradients within the system (maximum 20 °C across the mid-radius). A predictive pseudo-heterogeneous 2D reactor model was developed and validated against experimental data. The model accurately captured the observed trends in temperature profiles and outlet concentrations, and can be utilized for optimized design, paving the way for the development of efficient small-scale hydrogen production units.

Waste eggshell to valuable Co3O4/eggshell material as an efficient catalyst for catalytic decomposition of N2O under simulated real tail gases

Co3O4 shows excellent catalytic activity for N2O decomposition, in which it is urgently needed to develop novel efficient catalysts/supports with cheap and environmentally-friendly properties. Herein, Co3O4 nanoparticles decorated eggshell catalysts (Co3O4/eggshell-GR, Co3O4/eggshell-IM, and Co3O4/eggshell-DP) were prepared using simple grinding, impregnation, and deposition-precipitation methods, where waste eggshells were used as an effective support and reaction-promoter. The results indicated that the preparation methods significantly influenced the catalytic activity of Co3O4/eggshell catalysts; the highest activity was obtained over the Co3O4/eggshell-DP. The activity of Co3O4/eggshell-DP was comparable to that of pure Co3O4. More importantly, its specific activity was about 7.3 times that of Co3O4 at 400 °C. The examined Co3O4/eggshell-DP also displayed outstanding stability and anti-poisoning property in NO, O2, and/or H2O-containing atmospheres. It was also verified that the excellent activity of Co3O4/eggshell-DP correlated with the unique structure of the eggshell and the close incorporation between CaCO3 and Co3O4. The Co3O4/eggshell-DP catalyst owned abundant Co3O4 nanoparticles, more Co3+ species, and excellent redox performance, promoting the conversion of N2O at a lower temperature. The presence of abundant surface basic sites and a larger amount of oxygen vacancies also facilitated the catalytic efficiency of Co3O4/eggshell-DP.

Retracted: Utilization of Eco-Friendly Waste Eggshell Catalysts for Enhancing Liquid Product Yields through Pyrolysis of Forestry Residues

Retracted: Utilization of Eco-Friendly Waste Eggshell Catalysts for Enhancing Liquid Product Yields through Pyrolysis of Forestry Residues

Effect of process parameters on biodiesel yield produced from palm kernel shell oil (PKSO) using eggshell as catalyst

Effect of process parameters on biodiesel produced from PKSO and eggshell catalyst is investigated. The study showed the significant effect of the process parameters and properties on biodiesel yield. The appropriate reaction parameters that had the maximum biodiesel yield of 79.53% were 3% catalyst concentration, 150 minutes reaction time, 65oC reaction temperature, 12:1 methanol/oil molar ratio, and agitation speed of 300 rpm. Critical fuel properties such as; density, kinematic viscosity, flash point, fire point, cloud point, pour point, free fatty acid, aniline point, diesel index, API gravity, cetane, and fuel calorific values of the biodiesel obtained from all operating parameters were found to be between 0.8461 – 0.8831kg m-3, 5.31 – 7.84 mm2s-1, 97 – 141 oC, 107 – 150 oC, 4.14 – 6.5 oC, 1.5 – 4.5 oC, 0.318 – 0.931mgKOH/kg, 45 – 52 oC, 31.83 – 41.17, 28.165 – 33.258, 28.8313 – 41.1519, and 16 – 18% respectively. These values are within the accepted standard limits for diesel fuels.

Production of Biodiesel by Transesterification of Pilot Plant Waste over Nickel (Ni)/Eggshell (CaO) Catalyst

The increment of pilot plant waste at UniKL MICET and eggshell waste cause disposal problems, such as the water and soil pollution, human health concerns, and disruption to aquatic ecosystems. Thus, to reduce the effect of disposal problem to the environment, pilot plant waste is converted into biodiesel, while eggshell is converted into catalyst in this study. This paper reports on the effect of catalyst preparation method and reaction temperature on biodiesel yield and quality. Transesterification process of pilot plant waste (olein and stearin) was conducted by using Ni/CaO (eggshell) catalyst from different preparation methods at different reaction temperatures (328 K, 333 K, 338 K and constant reaction time (5 hours), methanol-to-oil ratio (15:1), and weight of catalyst (8 wt%). The catalysts were synthesized via wet impregnation and sol–gel method and its physicochemical properties were subsequently characterized by TGA and FTIR analysis. Biodiesel analysis was done using GCMS and FTIR, while the physical properties (density, flash point, and kinematic viscosity) of biodiesel were measured according to ASTM D6751. Kissinger-Akahira-Sunose (KAS) kinetic model shows that the catalyst prepared by wet impregnation method has the lowest activation energy, which was 81.48 kJ mol–1. In addition, GCMS analysis shows that reaction temperature at 338 K produced the highest yield of biodiesel (88.26%). In conclusion, the best catalyst preparation method was wet impregnation method and the best reaction temperature was 338 K. In addition, the physical properties of the produced biodiesel corresponded to ASTM standard, thereby indicating high quality of biodiesel and can be used as petroleum-diesel substitute.

Reaction Kinetics of an Industrial Front‐End Acetylene Hydrogenation Catalyst Using the Advanced TEMKIN Reactor

AbstractThe front‐end process integration of the selective acetylene hydrogenation provides several advantages over the tail‐end option. But extensive knowledge of the process and reaction kinetics are required. This work combines the ideal conditions of the advanced TEMKIN reactor in a laboratory plant for gradient‐free kinetic analysis of eggshell catalyst under industrially relevant front‐end conditions. With this system an industrial state of the art Pd‐Ag/Al2O3 eggshell catalyst is investigated and the temperature dependent data under various feed compositions including information on the formation of C4‐species are reported.

PRODUCTION OF BIODIESEL FROM MARULA SEED OIL USING EGG SHELL AS HETEROGENEOUS CATALYST

Diminishing fossil fuel resources, coupled with the steady increase in energy consumption, and have spurred research interest in alternative and renewable energy sources. In this research work, oil was extracted from marula seeds using soxhlet extractor and n-hexane as solvent. The extracted oil was characterized via physicochemical analysis then in-situ transesterification of oil with methanol was carried out using eggshell as catalyst. The physic-chemical analysis showed the state of the oil at room temperature to be liquid, the odour was mild, the colour was brown, specific density was 3.46, saponification value was 193.6 ± 0.25, acid value was 8.2 ± 0.4, and iodine value was 100.68 ± 1.0. Biodiesel characterization showed that kinematic viscosity at 40oC was 4.98, cetane number was 64.5, flash point was 159, pour point was - 13, cloud point was 5, and density was 0.85. The prepared eggshell catalyst was characterized using X-ray Fluorescence and was found to be composed of CaO (73.2), MgO (0.2), SiO2 (0.4), SO3 (0.3), P2O5 (0.7), Na2O (0.5), Al2O3 (0.07), K2O (0.03), and Fe2O3 (0.08). This study suggests that marula seed oil can be used as a source of triglycerides in the manufacture of biodiesel by transesterification. The properties of the biodiesel produced showed theoretical compatibility with diesel engines in accordance with the ASTM standard.

Utilization of Eco-Friendly Waste Eggshell Catalysts for Enhancing Liquid Product Yields through Pyrolysis of Forestry Residues

In this study, catalytic and noncatalytic pyrolysis of Prosopis juliflora biomass was carried out in a fluidized bed reactor. This study highlights the potential use of forestry residues with waste eggshells under a nitrogen environment. The experiments were conducted to increase the yield of bio-oil by changing the parameters such as pyrolysis temperature, particle size, and catalyst ratio. Under noncatalytic pyrolysis, a maximum bio-oil yield of 40.9 wt% was obtained when the feedstock was pyrolysed at 500°C. During catalytic pyrolysis, the yield of bio-oil was increased by up to 16.95% compared to the noncatalytic process due to the influence of Ca-rich wastes on devolatilization behavior. In particular, the existence of alkali and alkaline-earth metals present in eggshells might have positive effects on the decomposition of biomass material. The bio-oil obtained through catalytic pyrolysis under maximum yield conditions was analyzed for its physical and chemical characterization by Fourier transform infrared (FT-IR) spectroscopy and gas chromatography mass spectroscopy (GC-MS).

Synthesis of Biodiesel from Waste Cooking Oil Using Heterogeneous Catalyst (CaO) Based on Duck Eggshell with Transesterification Reaction

Biodiesel is produced from esterification and transesterification reactions of various vegetable oils such as coconut oil, palm oil, seed oil, soybean oil, etc. Waste cooking oil has the potential as a raw material for making biodiesel due to its abundant availability. The use of the CaO catalyst from duck eggshells can increase biodiesel quality. This study aimed to obtain the best catalyst with a high yield in biodiesel production using the transesterification method. The initial stage begins with activating the impregnated duck eggshell catalyst with various concentrations of KOH in distilled water (10 g KOH/100 mL, 15 g KOH/100 mL, 20 g KOH/100 mL, and 25 g KOH/100 mL). Followed by biodiesel synthesis steps using temperature variations in transesterification (45˚C, 55˚C, and 65˚C) in reaction times of 1, 2 and 3 hours using 2% catalyst concentration to the amount of waste cooking oil and a molar ratio of methanol: oil (7:1). The experimental results showed that transesterification of waste cooking oil could be improved with the presence of a CaO heterogeneous catalyst. The values of density, Free Fatty Acid (FFA), viscosity, and the acid number obtained was adjusted to the parameters using SNI:7182:2015. Only the total ester parameter (96.02%) and the cetane number (40.4) did not meet the requirements. Keywords: biodiesel, duck eggshell, waste cooking oil

Low-temperature oxidative removal of gaseous formaldehyde by an eggshell waste supported silver-manganese dioxide bimetallic catalyst with ultralow noble metal content

Under dark/low temperature (DLT) conditions, the oxidative removal of gaseous formaldehyde (FA) was studied using eggshell waste supported silver (Ag)-manganese dioxide (MnO2) bimetallic catalysts. To assess the synergistic effects between the two different metals, 0.03%-Ag-(0.5–5%)-MnO2/Eggshell catalysts were prepared and employed for DLT-oxidation of FA. The steady-state FA oxidation reaction rate (mmol g-1 h-1), when measured using 100 ppm FA at 80 °C (gas hourly space velocity (GHSV) of 5308 h-1), varied as follows: Ag-1.5%-MnO2/Eggshell-R (9.4) > Ag-3%-MnO2/Eggshell-R (8.1) > Ag-1.5%-MnO2/Eggshell (7.5) > Ag-5%-MnO2/Eggshell-R (7.2) > Ag-1.5%-MnO2/CaCO3-R (6.8) > MnO2-R (6) > Ag-0.5%-MnO2/Eggshell-R (3.2) > Ag/Eggshell-R (2.6). (Here, ‘R’ denotes hydrogen-based thermochemical reduction pretreatment.) The temperature required for 90% FA conversion (T90) at the same GHSV exhibited a contrary ordering: Ag/Eggshell-R (175 °C) > Ag-0.5%-MnO2/Eggshell-R (123 °C) > Ag-5%-MnO2/Eggshell-R (113 °C) > MnO2-R (99 °C) > Ag-1.5%-MnO2/Eggshell (96 °C) > Ag-3%-MnO2/Eggshell-R (93 °C) > Ag-1.5%-MnO2/Eggshell-R (77 °C). The eggshell catalyst outperformed the ones made of commercial calcium carbonate due to the presence of defects in the former. The MnO2 co-catalyst enhances the catalytic activities through the capture and activation of atmospheric oxygen (O2) with rapid catalytic regeneration. Also, MnO2 favorably captures the hydrogen of the adsorbed FA molecules to make the oxidation pathway thermodynamically more favorable.

Synthesis and Mathematical Modelling of the Preparation Process of Nickel-Alumina Catalysts with Egg-Shell Structures for Syngas Production via Reforming of Clean Model Biogas

For the work presented herein nickel catalysts supported on γ-alumina extrudates (Ni/Al) with an egg-shell structure were prepared, using a modified Equilibrium Deposition Filtration (EDF) technique. Their performance was compared, for the biogas dry reforming reaction, with corresponding Ni/Al catalysts with a uniform structure, synthesized via the conventional wet impregnation method. The bulk and surface physicochemical characteristics of all final catalysts were determined using ICP-AES, N2 adsorption-desorption isotherms, XRD, SEM, and TEM. A theoretical model describing the impregnation process for the EDF extrudates, based on the Lee and Aris model, was also developed. It was concluded that following specific impregnation conditions, the egg-shell macro-distributions can be successfully predicted, in agreement with the experimental results. It was shown that the Ni/Al catalysts with an egg-shell structure had a higher H2 yield in comparison with the ones with a uniform structure. The difference in catalytic performance was attributed to the improved surface and structural properties of the egg-shell catalysts, resulting from the modified EDF technique used for their preparation.

Egg shell catalyst and chicken waste biodiesel blends for improved performance, combustion and emission characteristics

Over the past few years, the research on the replacement of fossil fuel from inedible oil has been gaining more and more interest owing to the positive approach done on the waste animal fat for the reusable purpose. The performance, emission and combustion characteristics were measured for both diesel and chicken fat biodiesel blends (CFB). A small single cylinder, four stroke, air cooled, combustion ignition engine was used to conduct all tests. The biodiesel was produced by using transesterification process with the chicken eggshell dominated catalyst. The derived catalyst from the waste chicken eggshell was CaO used as a catalyst for the esterification process. The biodiesel blends used for conducting tests were B10 (10% of Chicken fat biooil + 90% diesel), B30 (30% of Chicken fat biooil + 70% diesel), B50 (50% of Chicken fat biooil + 50% diesel) and D100 or B0 (100% diesel). The Brake power (BP), Brake torque, Exhaust Gas Temperature (EGT), Brake specific fuel consumption (BSFC) and emission of CO, CO2, NOx and HC for all fuel blends were calculated and compared with pure diesel B0. All tests were conducted at different engine speed as 1800 rpm, 2000 rpm, 2200 rpm, 2400 rpm and 2600 rpm. From the performance qualities results, the biodiesel blends increased the brake power, BTE, EGT and HRR while reduced the CO, HC and smoke emissions. However, there was a little increment in NOX emission. The CFB is helpful in both overcoming the shortage of fossil fuel and better waste management.