Modelling a biorefinery concept producing carbon fibre-polybutylene succinate composite foam
- Authors: Ghayur, Adeel , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Chemical Engineering Science Vol. 209, no. (2019), p. 1-7
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- Description: In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
Techno-economic analysis of a succinic acid biorefinery coproducing acetic acid and dimethyl ether
- Authors: Ghayur, Adeel , Verheyen, Vincent , Meuleman, Erik
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Cleaner Production Vol. 230, no. (2019), p. 1165-1175
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- Description: The production of platform chemicals via carbon negative technologies will play an important role in global efforts to mitigate climate change. Succinic acid biorefineries are commercially mature carbon negative technologies that are plagued with large waste streams in the form of hemicellulose and gypsum. Here, a techno-economic analysis assesses the viability of a succinic acid biorefinery wherein hemicellulose is converted to acetic acid and dimethyl ether, and gypsum generation is avoided. Succinic acid is a feedstock for biodegradable plastics, acetic acid replaces petroleum-derived sources, and dimethyl ether is ideally suited as an energy storage vector. Our novel biorefinery concept presents an innovative integration of commercial technologies including water-splitting bipolar membrane electrodialysis for acid purification. The modelled multiproduct biorefinery (Multi Case)annually consumes 650,000 metric tonnes (t)of pulp logs, 135,000t of methanol, 1,700,000t of water, 42,000t of CO2 and 89 MW of electricity to produce 220,000t of succinic acid, 115,000t of acetic acid and 900t of dimethyl ether. All the parasitic electricity and heat duties are fulfilled within the biorefinery. Results show a CAPEX of AUD $635,000,000, OPEX of $180,000,000 and a succinic acid Minimum Selling Price of $990/t. Sensitivity and uncertainty analyses of the Multi Case biorefinery model show it is also resilient to price fluctuations.
Assessing transformer oil quality using deep convolutional networks
- Authors: Alam, Mohammad , Karmakar, Gour , Islam, Syed , Kamruzzaman, Joarder , Chetty, Madhu , Lim, Suryani , Appuhamillage, Gayan , Chattopadhyay, Gopi , Wilcox, Steve , Verheyen, Vincent
- Date: 2019
- Type: Text , Conference proceedings , Conference paper
- Relation: 29th Australasian Universities Power Engineering Conference, AUPEC 2019
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- Description: Electrical power grids comprise a significantly large number of transformers that interconnect power generation, transmission and distribution. These transformers having different MVA ratings are critical assets that require proper maintenance to provide long and uninterrupted electrical service. The mineral oil, an essential component of any transformer, not only provides cooling but also acts as an insulating medium within the transformer. The quality and the key dissolved properties of insulating mineral oil for the transformer are critical with its proper and reliable operation. However, traditional chemical diagnostic methods are expensive and time-consuming. A transformer oil image analysis approach, based on the entropy value of oil, which is inexpensive, effective and quick. However, the inability of entropy to estimate the vital transformer oil properties such as equivalent age, Neutralization Number (NN), dissipation factor (tanδ) and power factor (PF); and many intuitively derived constants usage limit its estimation accuracy. To address this issue, in this paper, we introduce an innovative transformer oil analysis using two deep convolutional learning techniques such as Convolutional Neural Network (ConvNet) and Residual Neural Network (ResNet). These two deep neural networks are chosen for this project as they have superior performance in computer vision. After estimating the equivalent aging year of transformer oil from its image by our proposed method, NN, tanδ and PF are computed using that estimated age. Our deep learning based techniques can accurately predict the transformer oil equivalent age, leading to calculate NN, tanδ and PF more accurately. The root means square error of estimated equivalent age produced by entropy, ConvNet and ResNet based methods are 0.718, 0.122 and 0.065, respectively. ConvNet and ResNet based methods have reduced the error of the oil age estimation by 83% and 91%, respectively compared to that of the entropy method. Our proposed oil image analysis can calculate the equivalent age that is very close to the actual age for all images used in the experiment. © 2019 IEEE.
- Description: E1
Colloidal carbon interference in the treatability of pulp and paper wastewater by MBR
- Authors: Scholes, Emily , Brook-Carter, Phillip , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Environmental Chemical Engineering Vol. 7, no. 5 (2019), p. 1-9
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- Description: Pulp and paper wastewaters are challenging to treat due to their variability, complexity and toxicity. Membrane Bioreactor’s (MBR’s) provide high-quality filtrates but are subject to periods of low filterability / high capillary suction time (CST) which potentially limit their use in this application. There is a paucity of published literature concerning long-term operational issues in full-scale, industrial MBR’s. We hypothesised that either changes of bacterial population, alteration/reduction of bacterial metabolism or bacterial production of extra-cellular polymers (ESPs) increased CST and reduced filterability. This study, conducted over two years at the 16.4MLD Gippsland Water Factory, was structured to inform this bacterial centric hypothesis. However, no shifts in bacterial population were seen as causative of high CST and microbial stress levels and biological activity were observed to be low during high CST and no sign of toxicity was found. The strongest correlator with CST was the concentration of colloidal Total Organic Carbon of the mixed liquor suspended solids (MLSS) supernatant (following centrifugation). The carbonaceous colloids accumulated in the supernatant were named ‘Non-Centrifugable Total Organic Carbon’ (NCTOC). Their accumulation in the MLSS was found be due to their biologically refractory nature and their retention by the MBR membrane. The accumulation of NCTOC typically followed a period where the influent had a high colour and a high sodium to calcium ratio, which is consistent with a pulping by-product called ‘Black Liquor’. Additional experiments with Black Liquor allowed us to conclude that high CST can be produced by addition of Black Liquor.
Techno-economic evaluation of amine-reclamation technologies and combined CO2/SO2 capture for Australian coal-fired plants
- Authors: Garg, Bharti , Haque, Nawshad , Cousins, Ashleigh , Pearson, Pauline , Verheyen, Vincent , Feron, Paul
- Date: 2020
- Type: Text , Journal article
- Relation: International Journal of Greenhouse Gas Control Vol. 98, no. (2020), p.
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- Description: CSIRO's patented CS-Cap process aims at reducing the costs of amine-based post-combustion capture by combining SO2 and CO2 capture using one absorbent in a single absorber column. By avoiding the need for a separate flue gas desulfurization unit, the process offers potential savings for power plants requiring CO2 capture. High-level cost estimates based on lab and pilot data are presented for two amine reclamation techniques i.e. thermal reclamation and reactive crystallisation. Only regeneration via reactive crystallisation reduces CS-Cap costs below base case FGD/SCR-PCC. Cost estimations suggest a potential reduction of 38–44% in the total plant cost when using the CS-Cap process compared to base case. However, the amine reclaimer operating cost governs the overall cost of the CS-Cap process and is highly sensitive to sulfur content. A 50% reduction is observed when SO2 levels reduce from 700 to 200 ppm. Comparing levelised cost of electricity and CO2 avoided costs for CS-Cap against our base case, low sulfur brown coal has a slight (5–7%) cost advantage; however, confirmation requires pilot data on amine recovery. © 2020
Use of MEA oxidation intermediates to monitor oxidation conditions during post-combustion capture of CO2
- Authors: Reynolds, Alicia , Verheyen, Vincent
- Date: 2019
- Type: Text , Conference paper
- Relation: 14th Greenhouse Gas Control Technologies Conference (GHGT-14); Melbourne 21-26 ; October 2018 p.
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- Description: Amine oxidation is a serious concern for post-combustion capture (PCC) of CO2 from fossil-fuel fired power stations. Organic acids are important oxidation products and have been measured in different ratios at different pilot plants. The concentrations of acetate, formate, glycolate and oxalate were measured in samples of degraded monoethanolamine from a variety of PCC pilot plants as well as laboratory-scale degradation experiments. The results suggest that the ratios of monoethanolamine oxidation intermediates (particularly glycolate and oxalate) have potential as process monitoring tools. Ultimately, ratios of these oxidation intermediates could be used to proactively manage and minimise oxidation of amine-based PCC absorbents by indicating the need for oxygen-scavenger addition or alerting operators to imminent increases in oxidative degradation rates.
The challenges of utilising bottom ash from waste to energy plant
- Authors: Venkatraman, Kartik , Wilcox, Steve , Verheyen, Vincent , Panther, Barbara
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Energy, Environment and Economics Vol. 28, no. 4 (2021), p. 305-333
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- Description: Bottom ash generated from Waste to Energy (WtE) processes is complex to manage and dispose of with minimal environmental impacts. Most European (EU) nations and many Asian countries have tested and developed alternative end-uses for bottom ash. This has ensured relatively safe containment of contaminants which otherwise would be released into the environment posing major risk to human, flora and fauna health. Although bottom ash has been physically and chemically incorporated into aggregates, cement and road construction, for example, the lifecycle and impact on the environment of these products are not yet quantified. The lifecycle of these materials and products that use bottom ash as one of their constituents needs to be completely understood, through these currently unanswered questions: What will be the fate of the contaminants? Is there a limit on the number of years before the contained contaminants will be released into the environment? Are we giving rise to a new problem with long term implications? This paper will focus on the thermal treatment of municipal solid waste and the resulting utilisation of bottom ash. © Nova Science Publishers, Inc.
Potential use of treated bottom ash as a capillary barrier in phytocaps
- Authors: Venkatraman, Kartik , Wilcox, Steve , Verheyen, Vincent , Panther, Barbara
- Date: 2021
- Type: Text , Journal article
- Relation: International Journal of Energy, Environment and Economics Vol. 28, no. 4 (2021), p. 271-304
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- Description: Waste to Energy (WtE) technology has been implemented in European and many Asia countries with tremendous success and social acceptance. Bottom Ash (BA) generated from this process has also been effectively used as raw material or by-product in many applications. This technology, however, is still in its infancy in Australia. Additionally, the market and appetite for enduse of BA is still to be explored. One such option for its enduse is in landfill capping as a capillary barrier to reduce water infiltration into buried waste. Bottom ash from WtE plants could be used as a capillary barrier in phytocaps-an alternative landfill capping techniques which uses tree and soil to reduce water infiltration into waste. Literature suggests that with proper treatment (stabilisation) or proper mixing and adequate curing, the hydraulic conductivity of BA can be increased (Circa 10-7 cm/s) by increasing its density and significantly reducing the threshold limits of heavy metals and other contaminants that may otherwise pose a risk to the environment. © Nova Science Publishers, Inc.