Waste Gas Research Articles

Protecting Lucid Waters and Lush Mountains of Hometown: Local-Born Mayors and Pollution Reduction

ABSTRACT Pollution prevention and control have garnered significant attention globally. Existing literature indicates that local officials play an important role in pollution abatement in China. We used unique firm-level data to investigate the impact of local-born mayors on pollution emissions. The results showed that local-born mayors could bring approximately a 4.41% reduction in pollution emissions; the pollution reduction is more pronounced in high-polluting cities, mayors with weaker promotion incentives, state-owned firms, and small firms. The potential mechanisms are encouraging high-polluting firms to install waste gas facilities and reducing government subsidies. Finally, we provided suggestive evidence supporting the information advantage and reputation effect of local-born mayors.

The Pyrolysis Characteristics of Bagasse Were Studied by TG-MS-FTIR

Sugarcane bagasse is rich in cellulose and lignin, and the recycling of bagasse has become an important research field with the increasing global concern for sustainable development and environmental protection. In this paper, TG-MS-FTIR equipment was used to analyze the pyrolysis characteristics of bagasse from Guangxi under different heating rates and different atmospheres, which is conducive to the reuse of bagasse from the waste gas produced in the sugar plant. The results showed that the pyrolysis rate of sugarcane bagasse in the air atmosphere was faster than that in the nitrogen atmosphere and showed a double-peak trend, and the Coats–Redfern computational model could more accurately simulate the process of pyrolysis. The lower heating rate could overcome the heat transfer hysteresis phenomenon in the process of pyrolysis. In the air atmosphere, the contact time between oxygen and volatile products was shorter due to the high heating rate, and more and more complex species were precipitated at 10 °C/min than at 20 °C/min. In the nitrogen atmosphere, it was favorable to produce more kinds and quantities of gas products, because it did not react with oxygen. FTIR detected CH4, CO, H2O, CO2, C-O-C, and C=O during pyrolysis in nitrogen, and some of C-O-C and C=O were cracked into small molecule compounds at high temperature.

Industrial Symbiosis Practices: A Case Study of Türkiye and Denmark

The term "industrial symbiosis (IS)" refers to a cooperative strategy where industrial actors share services and exchange physical resources. This method improves resource efficiency and lessens the environmental effects of industrial operations within the network. It is a cooperative method in which businesses trade and reuse physical resources such as by-products, water, and energy, as well as share services such as waste management and infrastructure. It has several advantages, such as (i) lowering greenhouse gas emissions through energy, process, input, disposal, and transportation savings, as well as fuel substitution; (ii) cutting energy expenses; (iii) diverting waste from landfills; (iv) avoiding the use of virgin materials; (v) lowering transportation and logistics costs; (vi) lowering pollution to land, water, and air; (vii) lowering industrial water use; (viii) lowering hazardous waste; (ix) creating economic value from waste material; and (x) simplifying environmental legislation and regulation compliance. In Türkiye and Denmark, the number of industrial companies is rapidly increasing. These industries consume many resources (such as raw materials, water, electricity, natural gas, coal, etc.) and generate a large amount of solid, liquid, and gaseous waste. IS is gaining popularity as an approach for improving the sustainability of industrial systems. The efforts to develop IS have emerged as a critical issue over the last decade in these two European countries. The paper presents the current implementation of IS in Türkiye and Denmark’s process sectors, focusing on well-known IS practices.

Thermodynamic and Economic Analysis of a High-efficiency System Integrating ORC Power Generation, CO2 Capture, and CO2 Storage Driven by Complementary LNG Cold Energy and Flue Gas Waste Heat.

Thermodynamic and Economic Analysis of a High-efficiency System Integrating ORC Power Generation, CO2 Capture, and CO2 Storage Driven by Complementary LNG Cold Energy and Flue Gas Waste Heat.

Effective decontamination of DR-81 dye from aqueous solutions using eco-friendly graphene oxide nanoparticles.

Effective management of industrial and agricultural wastes requires a multifaceted approach that considers environmental, economic, and social factors. Our ability to recover resources and create a circular bioeconomy from agricultural waste can be enhanced by implementing sustainable methods such as reducing, reusing, and recycling it. Active graphene oxide (GO) was prepared through the gasification of agricultural waste and further mixed with FeAlOx catalyst for three hours at 800°C as an efficient adsorbent. The synthesized material was comprehensively characterized using Fourier-transform infrared spectroscopy, X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller surface area analysis, and thermal gravimetrical analysis. In order to remove direct red 81 (DR-81) dye from wastewater, the synthesized nanomaterial was implemented as an effective adsorbent. Several processing variables, including pH, contact time, and dosage, were studied to examine the optimum conditions that directly influence the DR-81 decontamination of onto the fabricated GO. The optimal dosage from the synthesized GO for DR-81 decontamination was 0.5g/L at pH = 7 after 30min. At pH 7.0 and 25°C, the produced GO had the highest sorption capacity of 132.14mg/g towards the DR-81. In addition, equilibrium and kinetic studies were capably fitted via the Freundlich and pseudo-second-order models, respectively. As a result of its particular properties, which include a high surface area, adsorption capacity, structural robustness, variation tolerance, and thermal stability. These promising findings supported the usage of synthesized GO as a superior adsorbent material for DR-81 decontamination from wastewater.

CFD numerical simulation, verification with experimental results and internal flow analysis of bristle turbines

In industrial facilities, a considerable amount of waste heat is often generated. However, due to the high costs associated with traditional methods of recovery, which do not align with the economic interests of enterprises, this waste heat is frequently wasted. With technological advancements, the bristle turbine has been proposed as a solution capable of effectively managing waste gases and providing added value to enterprises. Its advantages lie in its simple structure, easy installation, low rotational speed, and high reliability, offering a new option for waste heat recovery and utilization. Despite its potential, no previous research has conducted a detailed simulation of the bristle turbine, particularly focusing on internal flow dynamics, energy loss mechanisms, drag forces, and entropy generation. This study is the first to explore these critical aspects, making a novel contribution to the field. The paper presents the computational fluid dynamics (CFD) simulation of a 20 kW bristle turbine. The numerical simulation results are in good agreement with experimental results. Subsequently, the isentropic efficiency of the turbine at different speeds is simulated, and the performance of the turbine under off-design conditions is analyzed. By investigating the energy loss mechanisms within the turbine, optimization designs are proposed.

The Effects of International Orientation on the Dimensions of the Environmental Performance of Agri‐Food Companies: A Chilean Perspective

ABSTRACTLike other Latin American economies, Chile has significantly increased its presence in international agriculture markets. Agricultural commodities are primarily developed within specialized exporters or multinational enterprises and exported to several different countries. In Chile, the fruit sector accounts for almost half of total exports. Internationally oriented companies explore business opportunities in foreign markets and invest adequate resources in international operations. In addition, more internationally oriented companies could be more inclined to invest in green practices due to external pressures and, consequently, achieve higher environmental performance. In this context, environmental performance is related to the extent to which available natural resources are protected during the production, delivery, and consumption of agricultural products. To the best of our knowledge, there is scattered evidence of the relationship between international orientation and the environmental performance of agri‐food companies, especially in Latin America. Grounded on the natural resources‐based view theory, this study assessed the effects of environmental collaboration on five dimensions of environmental performance (greenhouse gas emissions, energy efficiency, food loss and waste, food quality and safety, and water footprint management) in agri‐food companies with a survey with Chilean firms. Data were analyzed using the partial least square—structural equation modeling. We found that international orientation positively influences all five dimensions of environmental performance. Our study identified that the dimension most impacted by international orientation is water footprint management, and the least impacted is food quality and safety. With the aid of multi‐group analysis, we concluded that there are no significant differences in these relationships between micro/small and medium/large companies. A significant difference was observed in food loss and waste between fruit and nonfruit producers. We expect the outcomes of this study will support exporting‐related decisions and public policies in Latin America.

Underground Hydrogen Storage: Comparison of High-pressure Hydrogen, Liquid Hydrogen, and Ammonia

One of the alternatives for effective storage of irregularly produced renewable energy is hydrogen energy. In order to realize a hydrogen-based society, not only environmentally friendly production of hydrogen but also effective storage is very important. Underground hydrogen storage technology is a technology that has evolved from the technology for storing natural gas underground, and includes waste gas fields, salt domes, aquifers, and rock cavities. When stored underground, hydrogen is converted into high-pressure gaseous hydrogen, liquefied hydrogen, and ammonia. Liquefied hydrogen requires extremely low storage temperatures, and ammonia is a toxic substance that requires separate handling, and energy loss occurs during the conversion process. To compensate for this, research on liquefied hydrogen, such as multilayer insulation technology, is being conducted. Ammonia has successfully extracted high-purity hydrogen by developing a membrane reactor. Ammonia toxicity can be prevented by strengthening leak detection and blocking facilities. Among these, ammonia was found to be the most suitable for underground storage in terms of economic feasibility, environment, and commercialization.

Optimizing Syngas Production from Municipal Solid Waste Gasification: A Dual Reactor Fluidized Bed Study with Steam and CO2 as Gasification Agents

The escalating production of municipal solid waste (MSW) poses significant environmental and health hazards due to air, water, and soil pollution. Utilizing MSW as an energy source through gasification offers a promising solution to mitigate these impacts. This study investigates the gasification of MSW using a Dual Reactor Fluidized Bed, a thermal technology that converts solid substrates into usable gaseous fuels. The primary objective is to optimize the quality of the produced syngas by employing specific gasification agents, namely steam and CO2, and their mixtures. The research examines the effect of these agents on H2/CO ratios across a wide range of low operating temperatures, from 400°C to 700°C, using silica sand as a heat conduction medium between interconnected combustion and gasification reactors. The results demonstrate that the composition of syngas is strongly influenced by gasification temperature fluctuations. Increasing temperatures from 400°C to 700°C correlate with higher concentrations of CO and H2 in the syngas. The use of steam as a gasification agent yields H2 concentrations up to 25%, while transitioning from steam to CO2 leads to a substantial increase in CO composition, reaching 22.73%. Further analysis reveals that the H2/CO ratio decreases from 1,78 with steam and 0.64 with CO2, highlighting the crucial role of gasification agents in syngas quality. This study underscores the potential for optimizing syngas production from MSW by manipulating gasification temperatures and transitioning between different agents (steam, CO2, and their mixtures), resulting in an overall increase in the calorific value of the produced gas. These findings emphasize the opportunity to transform substantial environmental challenges associated with MSW into promising sustainable energy solutions through advanced gasification technologies.

PEMANFAATAN LIMBAH ORGANIK SEBAGAI ENERGI ALTERNATIF MENGGUNAKAN REAKTOR GASIFIKASI DOWNDRAFT

Organic waste from coconut shells, corn cobs, candlenut shells, and lamtoro wood is often found in the Gorontalo region. The gasification of organic waste has the potential to reduce organic waste and produce gas for various applications, including heating, power generation, and industrial raw materials. The research aims to determine the gas composition of the downdraft gasification process from organic waste from coconut shells, candlenut shells, corn cobs, and lamtoro wood, to determine the rate of fuel consumption, and to determine the calorific value. The method used is an experimental method. Test results using a downdraft gasifier reactor with 5 kg of fuel. The average H2 value obtained from the test results for coconut shells was 12.46%, candlenut shells 13.01%, corn cobs 9.3%, and lamtoro wood 15.95%, the highest H2 value from several of these samples was obtained from lamtoro wood with the highest percentage was 15.95%, the average O2 value obtained was coconut shell 8.86%, candlenut shell 6.37%, corn cob 2.61%, lamtoro wood 5.22%, the average CH4 value was shell coconut 7.88%, candlenut shell 4.05%, corn cob 8.03%, lamtoro wood 7.32%, average CO value for coconut shell 0.56%, candlenut shell 0.05%, corn cob 10 .71%, lamtoro wood 0.05% while the average N2 value obtained was 70.21% coconut shell, 76.49% candlenut shell, 69.25% corn cob, and 71.44% lamtoro wood. The findings compare four organic wastes as alternative energy using a downdraft gasification reactor. The conclusion from this research is that the best gas composition is from corncob organic waste with H₂, CH₄, and CO of 28.05%, the longest burning rate on corncob samples is 23.11 grams/minute and the highest calorific value test is on lamtoro wood samples with results reaching 4,340 cal/gram.

CIRCULAR ECONOMY AND ENVIRONMENT: ANALYSIS OF THE RELATIONSHIPS BETWEEN POPULATION, HOUSEHOLD AND SIMILAR WASTE AND GREENHOUSE GAS EMISSIONS IN ALGERIA (2010-2023)

Objective: The objective of this paper is to analyze the relationships between total population (POP), household and similar waste (DMA), and greenhouse gas emissions (GES) in Algeria from 2010 to 2023. The study explores trends in these variables and employs the Granger causality test to assess causal relationships between population growth, waste production, and emissions. Findings provide insights into the interdependencies among these factors. Recommendations for improving waste management through circular economy practices are also discussed. Theoretical Framework: The theoretical framework is based on the interrelationship between population growth, waste production, and greenhouse gas emissions. It posits that as population increases, household waste generation rises, which subsequently contributes to GHG emissions. This framework underpins the use of the Granger causality test to explore causal links among these variables in Algeria. Method: The study employs a descriptive analysis of the variables—total population, household waste (DMA), and greenhouse gas emissions (GES)—over the period 2010-2023. The Granger causality test is applied to examine causal relationships between total population and DMA, and between DMA and GES emissions. Data is analyzed to identify unidirectional causal links at a 5% significance level. Results and Discussion: Population growth directly impacts household waste (DMA) and greenhouse gas emissions (GES). Waste management is crucial for controlling emissions. Algeria needs to implement circular economy practices like recycling and waste sorting to mitigate environmental impact. Research Implications: Population growth in Algeria leads to increased waste production and emissions, necessitating improved waste management strategies and adoption of circular economy practices for sustainable development. Originality/Value: The study explores the link between population growth, household waste production, and greenhouse gas emissions in Algeria, offering insights for policymakers and sustainable waste management strategies.

Thraustochytrids and Algae as Sustainable Sources of Long-Chain Omega-3 Fatty Acids for Aquafeeds

There is limited ability to biosynthesize long-chain omega-3 fatty acids such as EPA and DHA in food webs leading to humans. Seafood is the key source of ω3 LC-PUFA, with aquaculture expected to meet rising global demand; however, marine fish have a high dietary requirement for EPA and DHA themselves. This was traditionally met using unsustainable dietary fish oil and fish meal, but limited supply and environmental concerns have dictated research on replacements. Among the industrial sources of EPA and DHA, microalgae and especially thraustochytrids stand out as resources with high concentrations. Although unicellular, thraustochytrids are not microalgae as they are not photosynthetic but instead are microheterotrophs. This removes the light requirement and facilitates high yields of monoculture for the production of single-cell oils. The availability, in high concentrations, of usually one or the other essential fatty acid permits a calibration of the EPA and DHA dose, which is especially useful as their effects have mainly been considered together in medical and aquaculture research. EPA and DHA have different effects on cell function and are precursors of different bioactive compounds. Using thraustochytrids, microalgae, and heterotrophic dinoflagellates, the importance of DHA has been investigated. DHA was essential for optimizing the growth of the early life stages of scallops and finfish and was preferentially incorporated into fish membrane phospholipids. The production of microalgae and microheterotrophs can contribute to the treatment of wastewater and waste gas, further enhancing their sustainability and reducing the environmental costs of aquaculture.

Fuel characterization and gasification of sunflower waste in sub- and supercritical water with influence of catalysts on optimum state

Fuel characterization and gasification of sunflower waste in sub- and supercritical water with influence of catalysts on optimum state

A Critical Review of Deep Oxidation of Gaseous Volatile Organic Compounds via Aqueous Advanced Oxidation Processes.

Volatile organic compounds (VOCs) are considered to be the most recalcitrant gaseous pollutants due to their high toxicity, diversity, complexity, and stability. Gas-solid catalytic oxidation methods have been intensively studied for VOC treatment while being greatly hampered by energy consumption, catalyst deactivation, and byproduct formation. Recently, aqueous advanced oxidation processes (AOPs) have attracted increasing interest for the deep oxidation of VOCs at room temperature, owing to the generation of abundant reactive oxygen species (ROS). However, current reviews mainly focus on VOC degradation performance and have not clarified the specific reaction process, degradation products, and paths of VOCs in different AOPs. This study systematically reviews recent advances in the application of aqueous AOPs for gaseous VOC removal. First, the VOC gas-liquid mass transfer and chemical oxidation processes are presented. Second, the latest research progress of VOC removal by various ROS is reviewed to study their degradation performances, pathways, and mechanisms. Finally, the current challenges and future strategies are discussed from the perspectives of synergistic oxidation of VOC mixtures, accurate oxidation, and resource utilization of target VOCs via aqueous AOPs. This perspective provides the latest information and research inspiration for the future industrial application of aqueous AOPs for VOC waste gas treatment.

Efficiency enhancement of a combined cycle power plant by thermal integration of multiple waste heat streams with organic Rankine cycle

AbstractThe study investigated the efficiency improvement of a 9.5 MW gas engine‐based combined cycle power plant utilizing multiple waste heat streams in an organic Rankine cycle. Four different waste heat sources were considered: I) boiler stack gas, II) engine jacket water, III) boiler steam, and IV) engines' exhaust gas. Besides, three different organic fluids; R245fa, R134a, and R1234ze(Z) were employed to find the best working fluid in the given operating conditions. The performance analysis of the ORC revealed that R245fa is a suitable potential fluid for cases I and II, whereas R134a performs better for cases III and IV. Integrating the ORC with the boiler stack using R245fa at 8 barg provided an additional 16.5% waste gas heat recovery. It increased the net electric efficiency of the existing plant by 0.7%. The jacket water heat recovery further improved the net electric efficiency by 2.1%. By integrating both streams with the ORC in the existing system, the net electrical efficiency was increased from 42.6% to 45.3%. The estimated payback period for the jacket water heat recovery scenario utilizing Chinese ORC equipment was 9.3 years. However, this period was significantly reduced to 4.6 years for general industry applications, rendering it economically viable.

Continuous Biological Ex Situ Methanation of CO2 and H2 in a Novel Inverse Membrane Reactor (IMR)

A promising approach for carbon dioxide (CO2) valorization and storing excess electricity is the biological methanation of hydrogen and carbon dioxide to methane. The primary challenge here is to supply sufficient quantities of dissolved hydrogen. The newly developed Inverse Membrane Reactor (IMR) allows for the spatial separation of the required reactant gases, hydrogen (H2) and carbon dioxide (CO2), and the degassing area for methane (CH4) output through commercially available ultrafiltration membranes, enabling a reactor design as a closed circuit for continuous methane production. In addition, the Inverse Membrane Reactor (IMR) facilitates the utilization of hydraulic pressure to enhance hydrogen (H2) input. One of the process’s advantages is the potential to utilize both carbon dioxide (CO2) from conventional biogas and CO2-rich industrial waste gas streams. An outstanding result from investigating the IMR revealed that, employing the membrane gassing concept, methane concentrations of over 90 vol.% could be consistently achieved through flexible gas input over a one-year test series. Following startup, only three supplemental nutrient additions were required in addition to hydrogen (H2) and carbon dioxide (CO2), which served as energy and carbon sources, respectively. The maximum achieved methane formation rate specific to membrane area was 87.7 LN of methane per m2 of membrane area per day at a product gas composition of 94 vol.% methane, 2 vol.% H2, and 4 vol.% CO2.

How the USA can feasibly cut methane emissions 30% by 2030: anaerobic digestion of organic waste and various measures in oil and gas production

AbstractThe USA has committed to cutting its emissions of methane, an extremely potent greenhouse gas, by at least 30% by 2030 (‘30 × 30’). This is part of the Global Methane Pledge, signed by 155 countries, to keep global warming within 1.5 °C and thereby to forestall the disastrous effects of ‘runaway climate change’. It will be a major challenge for the USA to reach 30 × 30 and there is no consensus on how to do so. This paper provides a concrete, data‐driven roadmap to indicate how to reach 30 × 30 feasibly, focusing on two enormous sources of methane emissions: organic waste and oil and gas production. It calculates that building approximately 4700 anaerobic digesters (ADs) to process food waste and animal manure would cost about $74.2 billion in capital expenditure (capex) and cut 13.6% of total US methane emissions per year. On average, each project would take roughly 2–6 years to build. Of the various methane mitigation measures analyzed in the oil and gas sectors, the most impactful would be full compliance with the US Environmental Protection Agency's (EPA's) revised New Source Performance Standards (NSPS) for oil and gas production by 2029. This would cut 17.5% of total US methane emissions annually, at a cumulative capex of $20.7 billion from 2024 to 2029. Together, the 13.6% cut from food waste and manure ADs and the 17.5% cut from full NSPS compliance would amount to a 31.5% reduction, exceeding the 30 × 30 goal. Greater clarity from the federal government on funding eligibility and additional incentives would accelerate the buildout of ADs.

Metaheuristic optimizing energy recovery from plastic waste in a gasification-based system for waste conversion and management

In an era where sustainable waste management and clean energy production are paramount, this study presents an innovative integration of plastic waste gasification with solid oxide fuel cell (SOFC) technology, optimized through metaheuristic particle swarm optimization (PSO). The research explores the conversion of polypropylene (PP) waste into syngas via gasification, which is then utilized as a fuel for SOFCs to generate electricity. The optimization process focuses on maximizing power and heating outputs while minimizing carbon dioxide emissions. The study's findings demonstrate the potential of integrating gasification and SOFC technologies to create a sustainable energy system that addresses the challenges of plastic waste. Key findings from the metaheuristic PSO multi-objective optimization reveal that optimal power production, approximately 360 kW, is achieved at temperatures exceeding 1140 K, irrespective of the steam/PP waste ratio. Heating production peaks at 1000 kW with temperatures above 1120 K and utilization factors over 0.765, while the minimum heating output is 700 kW. Emission analysis indicates a significant reduction in carbon dioxide emissions with increased temperatures and utilization factors, achieving a minimum of 700 kg/MWh at temperatures above 1120 K. The study's results demonstrate the effectiveness of the PSO optimization in fine-tuning the operational parameters of the integrated system, leading to improved energy efficiency and reduced environmental impact. Power production of 366.37 kW, a significant heating rate of 995.20 g/s, and emissions of 714.06 kg/MWh are the optimum performances. The research provides valuable insights into the potential of plastic waste-to-energy technologies as sustainable solutions for energy production and waste management.

Low Carbon Formaldehyde Generation from Chemical Looping Gasification of Heterogeneous Solid Waste

Low Carbon Formaldehyde Generation from Chemical Looping Gasification of Heterogeneous Solid Waste

The State of the Art on Phase Change Material-Modified Asphalt Pavement

During the construction and maintenance of asphalt pavement, a lot of non-renewable resources are consumed, which discharge a variety of waste gasses and smoke, causing a serious impact on the environment. Reducing society’s reliance on non-renewable resources is therefore key to improving sustainability. It is found that phase change materials (PCMs), as environmentally friendly materials, can spontaneously store and release heat energy by changing the phase state, thus reducing the adverse effect of temperature on asphalt pavement, reducing the occurrence of high-temperature stress, minimizing the cost of road construction and maintenance, and saving resources. In order to promote the application of PCMs in asphalt pavement, to promote self-controlling temperature technology for asphalt pavement, and to improve the sustainable development of asphalt pavement, this paper reviews the research status of PCMs in asphalt pavement, both domestically and abroad. The results show that the thermal conductivity of the modified asphalt binder can reach 0.29–0.39 W/mK, and the thermal diffusivity can reach 0.2–0.3 mm2/s, but the influence on the viscosity of the asphalt is limited, and both are less than 2000CP. The durability and thermal stability of the modified asphalt mixture are improved, and the maximum temperature can be lowered by 9 °C, which effectively reduces the occurrence of hightemperature stress. This review will help to better understand the function of PCMs and promote the sustainable development of green and environmentally friendly asphalt pavement.