1,721,025 research outputs found
Optimal ship-based CO2 transport chains from Mediterranean emission points to the North Sea
No full textCarbon capture and storage is one option for reducing industrial CO2 emissions. Ship CO2 transport is gaining interest due to its potential competitive cost, lower risk, and higher flexibility with respect to pipelines. This work focusses on the cost of ship CO2 transport chains in the European context. The objective is to develop an economic model of CO2 transport via ship, including the chain stages: liquefaction, buffer storage, loading, ship, conditioning, and unloading. An optimisation model is proposed to determine the minimum transport cost from Southern European ports to permanent geological storage in the North Sea. The minimum cost is found around 26 €/t of CO2 for a total transported CO2 of 103 Mt/y, which may be cost-competitive with pipelines for long distance routes via large vessels (greater than 50 kt)
Carbon-negative “emerald hydrogen” from electrified steam methane reforming of biogas: System integration and optimization
Full text linkThis work assesses a chemical plant for the conversion of biogas into negative emission “emerald hydrogen” via electrified reforming and CO2 separation. Electrification of the reformer allows for enhanced syngas production, compact reactor designs and flexible operation, thanks to the avoidance of combustion and heat transfer through pressure walls. The integration of the process with solar and wind power generation has been assessed by part-load process simulations and plant sizing and operation optimization through yearly simulations with hourly discretization. Different European locations with different wind and solar availabilities were assessed considering (i) short- and long-term cost scenarios for renewables and battery technologies and (ii) different plant size (from 390 to 3900 Nm^3/h of biogas capacity). The overarching scope of the paper is to calculate the cost of the produced hydrogen and the economic value of flexibility for plants installed in different locations, under different cost scenarios. At design load, the assessed process consumes 17.7 kWh of electricity per kg_H2 and retains 96% of the biogas chemical energy in the produced hydrogen. Additionally, 76% of the biogenic carbon is recovered as high-purity liquid CO2, achieving up to −9 kg_CO2/kg_H2 negative emissions. When powered with 95% of renewable energy, hydrogen production cost ranges from 2.5 to 2.9 €/kg for a long-term REN cost scenario and large-scale flexible plant to 5.9–7.1 €/kg for a short-term REN cost scenario and small-scale inflexible plants. For small-scale plants, flexibility allows to reduce the hydrogen production cost by 11–16% with respect to the inflexible plant in the short-term renewables cost scenario and by 1–4% in the long-term cost scenario. For large-scale plants, the adoption of a flexible plant leads to a reduction of 17–23% of the hydrogen cost in the short-term scenario and of 6–22% in the long-term scenario
Techno-economic evaluation of biomass-to-methanol production via circulating fluidized bed gasifier and solid oxide electrolysis cells: A comparative study
Full text linkMethanol is considered a promising solution for decarbonizing the transportation and chemical industry sectors, being a worldwide traded commodity that can be synthesized from biomass, renewable electricity, CO2 and other carbon-rich gases. This study investigates the potential of Solid Oxide Electrolysis Cells (SOEC) in enhancing the performance of bio-methanol production from biomass gasification. The research explores three distinct biomass-to-methanol plant configurations, incorporating an oxygen-blown Circulating Fluidized Bed Gasifier (CFBG) and different SOEC systems, namely: (i) steam electrolysis for hydrogen generation, (ii) co-electrolysis of steam and CO2 separated from syngas and (iii) direct supply of purified bio-syngas to the SOEC. The study reveals that, although the choice of SOEC type and system configuration could impact energy conversion efficiency and carbon efficiency, all plants show similar performance. In terms of Levelized Cost of Fuel (LCOF) and total efficiency, the syngas-electrolysis configuration exhibits the lowest LCOF, 21.56 €/GJ, and comparable total efficiency of around 80 % to the steam-electrolysis configuration. On the other hand, the CO2-H2O-electrolysis configuration showed the highest LCOF due to higher electricity consumption and capital investment
Utilization or Sequestration for Captured CO2 from Cement Plants?
No full textThe scope of this work is to assess the economic competitivity of optimized CO2 capture and utilization process (CCU) for e-methanol production with respect to CO2 capture and sequestration (CCS) in three locations (southern Italy, northern Germany, northeastern Egypt) and two economic scenarios (short- and long-term) for the cost of renewable energy technologies. The final aim is to determine the optimal sizing and operation of the process units of the system by minimizing the total costs to be sustained by a cement producer. At a methanol selling price of 550 /t, which is consistent with the current market price, CCS is economically more competitive than CCU in the short-term scenario in all locations. In the long-term scenario, due to the reduced costs of renewable energy technologies, CCU becomes the preferable option in a large majority of the assessed cases. In the long-term scenario, the breakeven methanol selling price in Italy with respect to CCS was found to increase from 384 /t to 570 /t if low-cost hydrogen storage is not available and H2 is stored in pressurized vessels (as alternative to caverns). In Germany, from 542 /t to 778 /t. In Egypt, from 402 to 501 /t. Overall, this study shows that e-methanol production from captured CO2 in European countries may be competitive with e-methanol produced in more favorable locations, such as Egypt, only in the long-term, at the condition of a substantial cost reduction of renewable energy technologies, and of the persistency of a differential cost of capital with respect to renewables-rich emerging countries
Optimisation of ship-based CO2 transport chains from Southern Europe to the North Sea
Full text linkAmong the technologies for climate change mitigation, carbon capture and storage is considered as a technically and economically viable option to reduce CO2 emissions from hard-to-abate industrial sectors. When it comes to CO2 logistics, ship-based chains are emerging as an attractive alternative to other CO2 transport modes (e.g., pipelines), as these could exhibit lower operational risk, higher infrastructural flexibility, and lower costs. This work provides insights into the cost of optimal ship-based CO2 transport chains at a European level, by proposing a detailed economic model of CO2 transport by ship, including all the echelons of the infrastructure (i.e., liquefaction, buffer storage, loading, ship, conditioning, and unloading). The final aim is to determine the minimum CO2 transport cost from Southern Europe to North Sea sequestration. Different unloading scenarios (port-to-port, port-to-floating storage and injection, and port-to-direct offshore unloading) and carbon reduction targets are investigated. The minimum unitary transport cost is 26 €/t of CO2 for transporting 103 Mt/y
Decarbonization of cement production by electrification
Full text linkThis study presents the techno-economic assessment of four electrified cement plants: i) using direct electrification and plasma technologies (eC-pK case); ii) consisting of indirect electrification via H2 combustion and oxycombustion of alternative fuels (OC-HK); iii) combining direct electrification, alternative fuels combustion and post-combustion CO2 capture (eC-afK); iv) consisting in the electrification of the hydraulic Calcium Hydro Silicate production process (e-hCHS). Process modeling in Aspen Plus is used to estimate mass and energy balances and calculate techno-economic key performance indicators. The study finds that all the electrified alternatives achieve high levels of equivalent CO2 emissions avoidance (87.2%-101.8%), with a trade-off between the electricity demand (604-1341 kWh/tclk) and the amount of captured CO2 to be handled by the transport & storage infrastructure (357-834 kgCO2/tclk). With an electricity price of 50 euro/MWh, the partially electrified alternatives (OC-HK, eC-afK) showed competitive additional cost of clinker (87 euro/tclk) and cost of avoided CO2 (101 euro/tCO2) against a benchmark case, though higher than the cost of the best CO2 capture technologies from the literature. The eC-pK case resulted in lower economic performance associated mainly to the higher price of electricity per unit of final energy supplied compared to alternative fuels
Improved flexibility and economics of Calcium Looping power plants by thermochemical energy storage
Full text linkIn this work, a Calcium looping (CaL) system including high temperature sorbent storage is presented, allowing to reduce the size of the calciner and the associated capital-intensive equipment (ASU and CPU). Reduction of the capital costs is particularly important for power plants with low capacity factors, which is becoming increasingly frequent for fossil fuel power plants in electric energy mixes with increasing share of intermittent renewables. The process assessment is performed by: (i) defining pulverized coal power plant (PCPP) with CaL capture system with and without sorbent storage and their mass and energy balances at nominal load; (ii) defining a simple method to predict the performance of the plant at part-load; (iii) defining the economic model, including functions for the estimation of the plant equipment cost; (iv) performing yearly simulations of the systems to calculate yearly electricity production, CO 2 emissions and levelized cost of electricity for different sizes of the calcination line and the storage system and (v) performing sensitivity analysis with different power production plans and carbon taxes. With this process, optimal size of the calciner and of the storage system minimizing the cost of electricity have been found. The optimal plant design was found to correspond to a solids storage system sized to manage the weekly cycling and a calciner line sized on the average weekly load. However, to avoid excessively large solids storage system, sizing the calciner on the average daily load and the storage system to manage the daily cycling appears more feasible from the logistic viewpoint and leads to minor economic penalty compared with the optimal plant design. For the selected case sized on the daily cycling, reduction of the cost of CO 2 avoided between 16% and 26% have been obtained compared to the reference CaL plant without solids storage, for representative medium and low capacity factor scenarios respectively
Optimising Carbon Capture and Storage Supply Chains for the European Industry
Full text linkCarbon capture and storage is considered of fundamental importance to achieve a remarkable decarbonisation of steel, cement and refining sectors. To operate carbon capture and storage at scale and address its inherent complexity, mathematical programming techniques can be exploited to optimise such systems. This contribution proposes a Europe-wide, spatially-explicit, time-dependent, carbon capture and storage chains optimisation, based on mixed integer linear programming architecture. Capture plants can be installed in all significant industrial CO2 emitters, which comprise 25 steel mills, 111 cement plants and 59 refineries. A techno-economic description of capture plants is provided, based on scale effects and different options. Transport can be operated through pipelines and offshore storage is taken into account in the North Sea and Adriatic area. The analysis allows identifying the most promising sectors and optimal specific plants where capture should be operated, and the evolution of the system throughout the time horizon. Considering a time-varying carbon reduction target, the avoidance cost is 75.6 €/t of CO2 for a North Sea targeted network, and decreases by 1.9% when sequestration in the Adriatic Sea is also taken into account
A Mathematical Tool for Optimising Carbon Capture, Utilisation and Sequestration Plants for e-MeOH Production
Full text linkCarbon capture, utilisation, and sequestration is key for the decarbonisation of hard-to-abate industries, as it allows avoiding the direct release of CO2 to the atmosphere and generating carbon-based products. However, for these products to be truly carbon-neutral, intermittent renewable electricity must be deployed at scale, leading to the necessity of optimising flexible plants with potential for local buffer storages, geological sequestration, and conversion units. The scope of this work is to provide a mathematical framework for the economic optimisation of a carbon capture, utilisation, and sequestration system, to decarbonise a cement plant located in the Puglia region (Italy), via CO2 geological confinement and/or power and CO2-to-methanol conversion. The final aim is to determine the optimal sizing and cost of the process units of the plant, depending on economic conditions such as the methanol sale price and different perspective costs scenarios. The main outcome is an economic convenience of geological sequestration, as opposed to utilisation, while a long-term scenario would allow for a cost-effective production of methanol when the sale price is above 550 EUR/t
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