Incineration Technology Research Articles

Energy Potential Generated from Municipal Solid Waste (MSW) at Tamangapa Landfill in Makassar City

This study aims to analyse the potential energy that can be generated from municipal solid waste (MSW) at Tamangapa landfill, check the adequacy of energy according to the target of 20 MW/day, and give consideration to WtE technologies that can be applied. The research began with a literature study, followed by a quantitative approach to calculate the potential energy that can be generated through incineration, gasification, pyrolysis, anaerobic digestion (AD) and fermentation WtE technologies. The results showed that the energy target of 20 MW/day from MSW in Makassar can be met through incineration (168.80 MW/day), gasification (28.29 MW/day) and pyrolysis (62.03 MW/day). However, if 20 MW/day is clean energy, then considering the energy conversion efficiency, 30.38 MW/day is obtained for incineration, 7.07 MW/day for gasification, and 15.51 MW/day for pyrolysis. Based on this calculation, only incineration technology can fulfil the 20 MW/day energy target as expected. In order to maximise the energy potential, it is recommended to use a combination of incineration WTE technologies for plastic, rubber, paper and fabric components, and pyrolysis for wood and food waste components.

Modeling of methane emissions from waste disposal sites at selected Egyptian governorates and potential energy production from waste-to-energy projects

Waste and energy sectors have significant contributions to the greenhouse gas (GHG) emissions caused primarily by the population expansion. Waste-to-Energy (WtE) is introduced to address the issue raised by both sectors simultaneously through utilization of the potential energy stored in municipal solid waste (MSW) as well as offsetting GHG emissions. Limited research have been conducted in Egypt to assess the current situation of MSW management and associated methane emissions. The current study focused on estimating the baseline methane emissions for six Egyptian governorates and determining the energy production potential from WtE projects. To achieve this aim, three scenarios have been assessed: Baseline, Landfill Gas to Energy (LFGE), and Incineration scenarios. Key results revealed that a total of 3.7 million tonnes of methane would be emitted from all studied governorates generated over 50 years. Incineration also found to be more favorable in all governorates in terms of energy production, quantity of avoided GHG emissions, and in terms of economic viability over LFGE. Implementing incineration in all governorates would generate about 5.6 TWh energy annually and could avoid about 5 Mt CO2 eq annually in comparison to LFGE that would generate about 0.6 TWh annually and could avoid about 2.5 Mt CO2 eq annually. In terms of economic viability of WtE projects, while they were generally not economically viable under the assumptions made in the current study, incineration technology deemed promising, but policy adjustments, such as competitive Feed-in Tariff (FiT) rates and the inclusion of gate fees, are necessary. Specific minimum gate fees and FiT were identified for each governorate, providing essential guidance for decision makers to ensure the viability of WtE implementation. This study would support the decision makers in assessing technically and financially feasible options for WtE technologies in the selected governorates.

Comparative Study on the Applicability of Solid Waste Treatment by Fixed Grate and Fluidized Bed Incinerators: A Bibliometric Review

Using thermal treatment in the waste management process has advantages such as reducing volume and the possibility of energy recovery. There are several incineration technologies with different characteristics and potential. Incineration, however, requires efficient environmental control to reduce associated risks, such as the emission of harmful compounds. The paper aims to compare solid waste treatment processes in grate and fluidized bed incinerators based on technical and environmental characteristics. For this purpose, a bibliometric review was conducted, and consulting works available in the scientific literature describe the waste treatment process with these two technologies. The searches were carried out in the Web of Science and Web of Knowledge databases using the following search engines: “fixed grade incinerator,” “grate incinerator” and “fluidized bed incinerator”. Grate incinerators present a range of elective waste for treatment compared to fluidized bed incinerators, as they do not require homogeneous waste. The study compared solid waste incineration in fixed grate and fluidized bed furnaces. While promising for sludge treatment, the fluidized bed technology may require pre-treatment, increasing costs and limiting its use to larger facilities. Fixed grate furnaces can handle a wider variety of waste without this additional step but generate more halogenated compounds when plastic waste is present. These technologies were primarily studied in Asia and Europe, where landfill space is limited and more significant potential for energy recovery exists. Adopting these technologies in other regions depends on waste characteristics, economic conditions, and environmental impacts.

Optimization of municipal solid waste incineration for low-NOx emissions through numerical simulation

With urbanization, municipal solid waste (MSW) generation is increasing. Traditional landfill methods face land shortages and environmental pollution. Waste incineration, which reduces waste and recovers resources, has become a key management method. However, nitrogen oxides (NOx) produced during incineration severely impact the environment, requiring improved control technologies. This study optimized three denitrification technologies—air staging, flue gas recirculation (FGR), and selective non-catalytic reduction (SNCR)—using numerical simulations. The research provides support for improving waste incinerator efficiency and stability while reducing NOx emissions, aiding the sustainable development of waste incineration technology. By optimizing the primary and secondary air distribution ratios, the initial NOx generation was reduced by 8.39%. When 20% of the recirculated flue gas was introduced as secondary air, NOx generation was reduced by 23.54%, and boiler efficiency increased to 83.78%. The study examined the impact of different sludge mixing ratios on the temperature and NOx emissions within the context of municipal solid waste (MSW) incineration. Initially, the study aimed to address the environmental concerns of NOx emissions during the incineration process by exploring how the introduction of sludge at various mixing ratios would affect combustion parameters. The results showed that a sludge mixing ratio between 3 and 13% optimized the combustion process with 7% being the most effective in balancing temperature control and NOx emissions. Specifically, the best value of the sludge mixing ratio refers to achieving an optimal reduction in NOx emissions while maintaining stable incinerator operation. The chemical compositions of the sludge included key elements such as carbon (C), hydrogen (H), nitrogen (N), sulfur (S), and oxygen (O), with approximate proportions of C: 31.2%, H: 4.7%, N: 2.5%, S: 0.6%, and O: 31.8%.

Environmental and economic analysis of the transformation of paper mill sludge treatment technologies in China.

Paper mill sludge (PMS) is featured with a high content of cellulose and hemicellulose, and using its characteristics to make paperboard can achieve a high-value utilization of PMS, which has attracted growing interest. In this study, currently prevalent landfill, incineration technologies (generating heat and electricity by incineration), and three paperboard technologies (medium density fiberboard, pulp board, and corrugated paper) were evaluated and compared via life cycle assessment (LCA) and life cycle costing (LCC) methods. LCA results show that the PMS-to-pulp board outperforms others with an energy conservation and emission reduction (ECER) value of - 2.86 × 10-8, while the landfill exhibits the highest overall environmental impact with an ECER value of 4.80 × 10-9. LCC results reveal that the PMS-to-pulp board delivers the highest economic profit with $257.357, while the landfill is the lowest with $ - 35.63. The PMS paperboard technologies are more economically friendly than the incineration technologies due to additional electricity/steam consumption during the PMS pre-drying process in incineration. In addition, different scenarios were set up to explore national GHG emission reduction potential by increasing paperboard technologies application rate and reducing the proportion of landfill and incineration. The scenario analysis suggests that replacing 90% of landfill and incineration ratio with PMS paperboard technologies could tremendously improve the overall emission reduction performance with - 9.08 × 1010 kg CO2 eq. This result indicates that the PMS treatment technology transformation has a significant favorable impact on the achievement of the "carbon neutrality" target.

Demineralization effects on physicochemical and combustion characteristics of biomass: Insights into distributed kinetics, flue gas evolution, and slag formation

Biomass as the only carbon-bearing renewable energy has enormous potential to challenge the established energy structure dominated by fossil resources, and incineration technology is one of the most direct and efficient pathways for utilizing biomass resources, unfortunately enduring the inevitable sintering and slagging problems owing to the excessive alkali metals. Herein, we comparatively investigated the effects of five leaching solvents (water, acetic acid, wood vinegar, hydrochloric acid, and oxalic acid) on the physicochemical properties and ash-removal capabilities of wheat straw (WS) and rice husk (RH), with a view to achieving better performance in the subsequent combustion characteristics, kinetic examination, flue gas, and slag evolution. Results indicated with ionization ability increased (water < acetic acid < hydrochloric acid), the WS exhibited a strong demineralization performance (maximum 61.1%), further leading to a steep weight loss in its combustion characteristic curve at approximately 350 °C and a delayed peak temperature after the removal of alkali metal. Multiple distributed activation energy model and sensitivity analysis revealed that leaching pretreatment enhanced the activation energy (189–191.8 kJ mol−1) and optimized energy distribution at the preliminary stage of the combustion reaction. In addition, the absence of alkali metals suppressed the catalytic oxidation reaction in the flue gas, remarkably limiting the formation of CO2 but facilitating the release of CO and CH4. Meanwhile, a considerable optimal in biomass ash slagging, in which the initial temperature of the liquid phase slag for WS ash increased to 991 °C. Notably, HCl showed the strongest demineralization performance among the five leaching solvents during pretreatment, but the high-temperature slag content was still higher than that of acetic acid. Therefore, slagging performance is not only associated with the demineralization ability of leaching solvents, but also with ash composition.

Waste Management Based On Waste To Energy Technology In Palopo City

The volume of waste in Indonesia especially in Palopo City increases every year, while the quality of waste management does not show good performance. The large population makes high consumption including energy needs, even though most of the national energy needs come from coal which is a source of pollutants. Waste to energy (WTE) is a modern waste management that utilizes waste into renewable energy, the conversion of waste into energy can be done with landfill gas (LFG) technology and incineration. The study aims to analyze the potential of waste management based on waste-to-energy technology in Palopo City. Quantitative descriptive research with observation and documentation instruments. To calculate the potential energy produced using LandGem-v302 and mathematical equations, to assess the feasibility of economic value using the criteria npv, irr, brc, and pp. The results of this study show that gas landfill technology has the potential to produce renewable energy. The results of the economic feasibility assessment of gas landfill technology meet all four criteria, thus the development of gas landfill technology can provide economic benefits. The results of incineration technology research have the potential to produce renewable energy. But from the results of the economic feasibility assessment unlike gas landfills, the combustion technology does not meet one of the economic value feasibility criteria. So the development of centration technology is not recommended to obtain economic benefits, the development of incineration technology is recommended to reduce waste.

Pilot-tests of the coal-fired power plant indirect coupling with multi-source organic solid waste incineration technology

The production of organic solid waste is increasing as the development of society. However, the investment of waste incineration power plant is very high and the thermal efficiency is very low. At the same time, the load of coal-fired power plant is suppressed due to the carbon neutralization policy. Therefore, using the existed coal-fired power plant to co-process the organic solid waste is a feasible method. In this paper, a coal-fired power plant indirect coupling with waste incineration technology based on flue gas circulation was proposed and studied on a 100 kW pilot-test bench. In this technology, the polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) was reduced by a three stages controlling method, which adopts the blending of multi-source organic wastes, high-temperature decomposition and selective catalytic reduction (SCR) catalyst decomposition, simultaneously. The effects of waste incineration coupling, replacement ratio of coal, and flue gas circulation on the combustion and pollutant emission characteristics of the system were studied. The experimental results indicate that the waste incineration coupling has minor influence on the temperature distribution and the toxicity of fly ash of the coal-fired furnace. The NO, HCl, and PCDD/Fs concentrations of flue gas of coal-fired furnace generally decrease as the replacement ratio of coal increases, while the SO2 concentration increases. With the help of three stages controlling method or the flue gas circulation, the PCDDFs concentration of the flue gas of coal-fired furnace can be much lower than 0.1 TEQ ng/Nm3.

Mitigating ash-related alkali and heavy metals emissions in rotary kiln through oxygen-carrier-aided combustion of waste

Rotary kiln (RK) incineration technology gains prominence in waste management, aiming to reduce pollution, recover energy, and minimize waste. Oxygen-carrier (OC)-aided incineration of waste in the RK demonstrates notable benefits by enhancing oxygen distribution uniformity and facilitating fuel conversion. However, the effects of OC on ash-related alkali and heavy metals during waste incineration in the RK remain unknown. In this study, manganese ore and ilmenite as OCs are introduced into RK during waste combustion, focusing on their effects on the bottom ashes and the behavior of alkali and heavy metals. Results show that manganese ore exhibits a decreasing reactivity due to oxygen depletion during the conversion from Mn2O3 to Mn3O4, while ilmenite maintains good reactivity due to sustained enrichment of Fe2O3 on the particles even after multiple cycles in RK. The porous structure on the surface of OCs particles verifies the cyclic reaction involving oxidation by air and reduction by fuel as OCs move between the active and passive layers of the bed. The porous OCs particles offer abundant adsorption sites for K from the gaseous phase, with surface-deposited K migrating into the particles and enhancing the OCs' capacity for K adsorption. Adding OCs promotes the formation of stable, less volatile compounds of heavy metals (As, Cr, Pb, and Zn) and enhances their retention in bottom ash while ensuring the leaching toxicity remains below Chinese national standard limits. This study enhances the understanding of OCs in incineration, guiding vital references for waste management practices and environmental sustainability.

Occurrence, distribution and annual emissions of chlorinated paraffins in hazardous byproducts from municipal solid waste incineration plants in South China

Nowadays incineration technology has become the most mainstream way for the disposal of municipal wastes. Short chain chlorinated paraffins (SCCPs) and medium chain chlorinated paraffins (MCCPs) are currently classified as new persistent organic pollutants (POPs) and candidate POPs under the Stockholm Convention, respectively. However, the occurrence and contamination characteristics of these main hazardous byproducts (e.g., leachate, fly ash, and bottom ash) from municipal solid waste incineration (MSWI) plants have remained unknown. This study focused on the SCCPs and MCCPs (defined as CPs) contamination and their annual emissions from leachate, fly ash, and bottom ash among three typical MSWI plants in Shenzhen, South China. Compared to the dissolved phase of the leachate, higher concentrations of CPs were detected in the adsorbed phase. The total concentrations of CPs ranged from lower method detection limits (<MDLs) to 448 ng/g in fly ash and 124 to 7230 ng/g in bottom ash. The ratios of MCCPs to SCCPs were generally >1 in leachate (i.e., adsorbed phase) and bottom ash, while the opposite results were found in fly ash. The dominant SCCP congener groups were C10Cl6–7 in leachate and fly ash, and C13Cl6–7 in bottom ash. The dominant MCCP congener groups were C14Cl7–8 in leachate, fly ash and bottom ash samples. Principal component analysis (PCA) revealed the dominant CPs in fly ash were obviously different from those in leachate and bottom ash. Estimated total annual emissions of CPs from the three main hazardous byproducts generated from typical MSWI plants were estimated between 66.2 and 7510 kg/y and bottom ash contributed the most to the CP emissions. Overall, this study is the first report on CP contamination in hazardous byproducts from MSWI plants, and can provide basic data support for CP contamination control.

Assessment of the energy potential of municipal solid waste: A case study of Mussaka dumpsite, Buea Cameroon

A country's economic growth and urbanization often lead to environmental degradation due to the amount of waste generated. Proximate analysis was done. The objective of this study is to evaluate the energy potential of the municipal solid waste (MSW) in Buea municipality through landfill gas-to-energy and incineration technology. Methane emissions from the Mussaka dumpsite for two decades using the Inter-Governmental Panel on Climate Change (IPCC) default method (DM) and Landfill Gas Emission Model (LandGEM V3.03) models were estimated. The Buea municipality's 2022 combustible MSW generated 40,593.69 tons with a low heating value of 7.37 MJ/kg, potentially producing 20.5 GWh of energy. LandGEM and IPCC DM models predicted total methane emissions during the period 2010–2030 as 21.33Gg and 54.77Gg, with annual energy potentials ranging from 0 to 5.10 GWh and 2.91 to 15.31 GWh respectively. This study provides crucial information for waste management investors and policymakers.

Examining waste-to-energy technology potential through the pilot project of Bantargebang Waste-to-Energy Power Plant

Municipal waste management in Indonesia, particularly Jakarta, poses a significant environmental challenge. Jakarta has been relying on the Bantargebang landfill to address its waste disposal needs for many years. Due to the persistent accumulation of waste, the Bantargebang landfill nears its maximum capacity. In response, a Waste-to-Energy (WtE) power plant was introduced in Bantargebang, serving as a pioneering initiative for WtE technology implementation in Indonesia. The Bantargebang WtE Plant employs incineration technology to convert municipal waste into electricity. Despite its usefulness, there are general environmental concerns about WtE plants, specifically focusing on their emissions and the potential presence of hazardous substances This research assesses the Bantargebang WtE Plant’s performance based on 2022 operational data, specifically examining waste reduction efforts and comparing incineration byproducts, including FABA (Fly Ash, Bottom Ash), and flue gas emissions, against government standards. The study indicates the plant can reduce waste mass by 96.5%. Furthermore, the WtE plant’s byproducts align with government standards for flue gas emissions and FABA residue. These results emphasize the potential of large-scale WtE power plants to achieve sustainable waste management goals in Indonesia. Nonetheless, there are opportunities for maximising waste accumulation reduction performance and enhancing operational value of WtE plant.

Technical and Economic Feasibility of Different Urban Sludge Treatment Technologies

Currently, the level of urban sewage treatment technology in China is very mature, but the development of urban sludge technology lags behind. In some cities, sludge has not been effectively treated for a long time, emitting foul odors that seriously affect people’s daily lives. Moreover, heavy metals and pathogens cause corrosion and damage to the land. Therefore, it is particularly important to choose an efficient and environmentally friendly approach to urban sludge treatment. This article lists three routes for urban sludge treatment. The Ebsilon software was used to simulate the co-combustion process of coal and sludge in the sludge incineration route. Based on domestic and international research results, the technical characteristics of sludge pyrolysis and composting were analyzed. The research method of comparative analysis was adopted to comprehensively compare and analyze the technical characteristics and return on investment (ROI) of the three routes. This research method can intuitively demonstrate the advantages and disadvantages of the three routes, and accurately and quantitatively determine the best route. In conclusion, Route 1: the comprehensive treatment process of drying and incineration is currently the most suitable route for China’s development prospects. It has the most mature technology and the widest range of applications, achieving the highest efficiency in sludge treatment. In the foreseeable future, sludge incineration technology will remain the cornerstone of sludge treatment and disposal in China.

Waste-to-energy incineration site selection framework based on heterogeneous fuzzy regret-PROMETHEE model considering life-cycle carbon emissions.

Waste incineration technology has received extensive attention for its advantages of being harmless, reducing, and recycling. However, the waste-to-energy incineration project confronts significant "not-in-my-backyard (NIMBY) concerns," and irrational location choices will have negative effects on the project's economy and sustainability; it is also a great challenge to the credibility of the government. To this end, a multi-criteria decision-making framework is constructed for the site selection of waste-to-energy incineration projects. To begin with, a site selection criteria system is established including 16 sub-criteria from four aspects, where probabilistic linguistic term sets are introduced to depict the qualitative sub-criteria and probabilistic hesitant fuzzy sets are employed to express the uncertainty of quantitative sub-criteria. An optimization model is then built to determine the weights of criteria based on the Pearson correlation coefficient and least square method. Furthermore, a regret-preference ranking organization methods for enrichment evaluations (PROMETHEE) model is presented to rank alternatives in a heterogeneous decision environment. Finally, a case study in China is conducted to validate the applicability of the proposed framework; the result of the site selection demonstrates that alternative A2 located in Miyun, Beijing, is the most optimal option. This work provides investors with scientific decision reference and also extends the methods in the decision-making field.

Environmental and economic assessments of industry-level medical waste disposal technologies – A case study of ten Chinese megacities

Medical waste (MW) is exploding due to the COVID-19 pandemic, posing a significant environmental threat, and leading to the urgent requirement for affordable and environmentally friendly MW disposal technologies. Prior research on individual MW disposal plants is region-specific, applying these results to other regions may introduce bias. In this study, major MW disposal technologies in China, i.e., incineration technologies (pyrolysis incineration and rotary kiln incineration), and sterilization technologies (steam sterilization, microwave sterilization, and chemical disinfection) with residue landfill or incineration were analyzed from an industry-level perspective via life cycle assessment (LCA), life cycle costing (LCC) and net present value (NPV) methods. Life cycle inventories and economic cost data for 4–5 typical companies were selected from 128 distinct enterprises and academic sources for each technology. LCA results show that microwave sterilization with residue incineration has the lowest environmental impact, emitting only 480 kg CO2 eq. LCC and NPV analyses indicate that steam sterilization with landfilling is the most economical, yielding revenues of 1,210 CNY/t and breaking even in the first year. Conversely, pyrolysis and rotary kiln incineration break even between the 4th and 5th years. Greenhouse gas emissions from the MW disposal in ten cities with the largest MW production in 2020 increased by 7% over 2019 to 43,800 tons and other pollutants increased by 6% to 12%. Economically, Shanghai exhibits the highest cost-effectiveness, while Nanjing delivers the lowest. It can be observed that the adoption of optimal environmental technologies has resulted in a diminution of greenhouse gas emissions by 279,000 tons and energy conservation of 1.76 billion MJ.

Environmental Sustainable in Household Waste Management For Urban Resilience: Insight From Makassar City, Indonesia

This study only focuses on a small aspect of environmental protection, namely proper household waste management for urban resilience in Makassar City, Indonesia. This study discusses how household waste in Makassar City can be converted into useful products and economic value that will reduce waste generation and maintain the preservation of densely populated urban environments in Makassar City, Indonesia. This study methodology is qualitative with a case study approach in looking at environmental degradation caused by an increase in household waste generation in Makassar City which has an impact on the environment and socio-economic activities of Makassar City community. The results of this study indicate that the development of environmental problems in household waste management in Makassar City is still experiencing problems. So in good governance, it is driven by the helix innovation system which involves various stakeholders to turn household waste into useful products with economic value. The helix innovation system as a solution to the problem of increasing household waste in Makassar City utilizes Incineration Technology and the Waste Bank and Composting Innovation Program for organic waste as environmental preservation for densely populated cities in Makassar City, Indonesia which involves community groups. Wet household organic waste is made into compost which can be used in plantations and livestock. Waste management in Makassar City is regulated in Makassar Mayor Regulation No. 4 of 2011 concerning Waste Management and Makassar Mayor Regulation No. 35 of 2018 concerning Policies and Strategies for Household Waste Management and Household Waste.

Economic and environmental optimisation of mixed plastic waste supply chains in Northern Italy comparing incineration and pyrolysis technologies

In the quest for sustainable plastic waste management, understanding economic and environmental implications enables optimal selection of treatment technologies. This study presents a multi-objective mixed integer linear programming framework to optimise the supply chain for mixed plastic waste in Northern Italy. Two technologies are considered: incineration and pyrolysis. Results offer quantitative insights into economic and environmental performance, balancing trade-offs between maximising gross profit and minimising greenhouse gas (GHG) emissions. Economic optimisation favours incineration for treating mixed plastic waste, resulting in the highest gross profit of 115 M€ per year, and the highest net GHG emissions of about 680 kt CO2eq per year. When the aim is environmental optimisation, pyrolysis is preferred due to its lower GHG emissions of 387 kt of CO2eq per year and yielding a gross profit of 54 M€ per year. Trade-off Pareto optimal solutions were analysed to identify reasonable trade-off configurations between the two objectives.

Manufacture of alkali-activated cementitious materials using municipal solid waste incineration fly ash (MSWIFA): The effect of the Si/Al molar ratio on fresh and hardened properties

Due to the escalating production of municipal solid waste and the widespread adoption of incineration technology, there is a substantial demand for secure disposal of municipal solid waste incineration fly ash (MSWIFA). In this research, alkali-activated MSWIFA via combination with metakaolin (MK) and cement was used to produce an eco-friendly composite. The influence of Na2O content and modulus (Ms) of alkali activator on the early compressive strength and setting time of the composites was investigated, and 4 wt% Na2O content was found to be the most appropriate alkali content. Then, the influence of the Si/Al ratio (2.35–3.18) on the fresh properties (initial setting time, rheology properties, and hydration heat) and hardened properties (compressive strength and shrinkage performance) of composite materials was studied. The microscopic mechanism of the effect of the Si/Al ratio on material properties was explained by XRD, TG, and SEM-EDX. The results showed that the compressive strength of the composite can reach 16.4 MPa at 28 days, which met the quality standard of MU15 (GB/T 25779–2010) of load-bearing concrete perforated brick. With the increase of the Si/Al ratio, the setting time of the slurry is prolonged and the rheological property has deteriorated. The composites with a lower Si/Al ratio (2.35) have the densest structure and the lowest degree of drying shrinkage, which leads to a higher strength. This study provides a potential solution for MSWIFA solidification in low-carbon construction applications.

An analysis of waste/biomass gasification producing hydrogen-rich syngas: A review

In the last few decades, the population growth level has increased exponentially so the waste disposal level has increased gradually. Wastes like biodegradable wastes, kitchen wastes, hotel wastes, and other agro wastes can be processed through bio methanation and composting technology but non-biodegradable materials like plastics, rubber, industrial sludge, and other wastes cannot be processed in simple ways or technologies. These wastes are critical to handle and need robust technology. Gasification and incinerators are a technology to utilize these waste materials and convert them into useful energy. However, the incinerator has a drawback of control over emissions generated by waste material combustion. Gasification is the best-suited technology which can convert the waste material into gaseous form and this gas provides heat to the prime movers to generate energy/power. Carbon monoxide, hydrogen, methane, carbon dioxide, oxygen, and nitrogen are the main components of synthetic gas (syngas), which has a low calorific value. Increased hydrogen and carbon monoxide concentrations improve this gas's calorific value. Different gasification methods like gasification using agent as steam, catalytic gasification, and gasification using different combination of fuels (waste-coal/biomass) are used to enrich the hydrogen content of the syngas. This paper reviewed the theory of waste-to-energy technologies, incineration technology, gasification technology, methods for increasing hydrogen in syngas, also different methods. This review discusses waste gasification disposal methods and hydrogen enrichment.

NO/SO2/HCl emissions from solid waste combustion via oxygen-carrier-aided combustion in rotary kiln

Rotary kiln incineration technology has become an important approach to achieve the harmless, reduced, and resourceful solid waste (SW) due to its wide range of fuel adaptability and high treatment efficiency. SW incineration through oxygen carrier (OC) aided combustion in the rotary kiln shows significant advantages in improving SW conversion and reducing CO emission. However, the impacts of introducing OC into the rotary kiln on the emissions of NO, SO2, and HCl, are still unknown. This research objective was to investigate the effects of OCs on the emission characteristics of NO, SO2, and HCl. Natural manganese and ilmenite ores as OCs, are added to a continuous-feeding rotary kiln during the combustion of biomass SW and hazardous SW. The results show that the introduction of OCs can significantly improve the uniformity of oxygen distribution in the furnace, and promotes the conversion of fuel N to NO. At high temperatures and low oxygen concentrations range, the reduction rate of NO by high-concentration CO or catalytic reduction by char and ash is faster than the oxidation of fuel N by OCs, which decreases NO concentration. Moreover, at high temperatures, when OCs are distributed in the bed of the rotary kiln, the fuel in the oxygen-poor zone can obtain O2 or lattice oxygen from the OCs, which promotes the decomposition and oxidation of S-containing compounds in fuels and increase the SO2 concentration. In addition, OCs in the bed provide more reaction sites for fuel conversion and promote the release of Cl as HCl at high temperatures. Specifically, during the oil sludge combustion at 900 °C, compared with the inert reference case, the addition of ilmenite ore increased the concentrations of NO, SO2, and HCl by 47.44%, 64.87%, and 20.28%, respectively, which is attributed to the better reactivity and redox cycle stability of ilmenite ore. This study highlights the potential of OC-aided combustion in rotary kilns as an approach to regulate SW combustion and offers a foundation for the future related research.