| 1. |
- Biermann, Max, 1989, et al.
(författare)
-
Efficient utilization of industrial excess heat for carbon capture and district heating
- 2020
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Carbon capture and storage (CCS) from fossil and biogenic (BECCS) emission sources is necessary to limit global warming to well below 2°C. The EU as well as Swedish national agencies emphasize the importance of CCS for emission intensive industries. However, the cost of implementing CCS is currently still higher than the cost of emitting CO2 via the EU ETS, for example. To incentivize rapid deployment of CCS, the concept of partial capture has been suggested, i.e. capturing only a fraction of the site emissions to reduce capture cost. Several studies have found that the utilization of excess heat from industrial processes could significantly reduce the capture cost as the heat required (~120°C) may be available in significant quantities. However, available excess heat will not be sufficient to power full capture at most industrial sites. In Sweden, many industries utilize all or part of their excess heat in heat recovery units or in combined heat and power (CHP) plants to produce electricity and deliver heat to municipal district heating (MDH) systems. A broad implementation of CCS will, thus, effect the availability of excess heat for industrial heat and power generation. The future product portfolio of industrial processes with excess heat export and CHP plants can therefore be expected to include not only heat and power production, but also climate services (CCS/BECCS) and grid services (frequency regulation due to intermittent renewables). The aim of this work is to assess partial capture at sites that have access to low-value excess heat to power the capture process, whilst considering competition from using the excess heat for MDH delivery. The work is based on process modelling and cost estimation of CO2 capture processes using amine absorption for two illustrative case studies, a refinery and a steel mill, which both currently use excess heat for MDH. The main focus is on investigating how seasonal variations in the availability of excess heat as well as the demand of district heating impact cost-efficient design and operation of partial capture at industrial sites. A challenge when utilizing excess heat in connection to a process connected to a district heating system is that the heat source which can be used to power part of the capture process will exhibit seasonal availability, and thus may inflict extra cost for the CCS plant not running at full load, and therefore may counteract the economic motivation for partial capture. To prevent this, heat integration between CCS and municipal district heating is investigated, for example by utilizing heat from the CO2 compression so that low-pressure steam is released from MDH to provide heat to capture CO2 whilst maintaining MDH supply. The design of the amine absorption capture process will have to handle significant load changes and still maintain high separation efficiency within hydrodynamic boundaries of the absorber and stripper columns. The cost of such operation will depend on the solvent circulation flows, the number of absorber columns (including packing and liquid collectors/distributors) and capacity of solvent buffer tanks for storing unused solvent during the winter season. Assuming that a constant amount of CO2 is avoided, the avoidance cost of CCS based on excess heat with seasonal heat load variations is compared to the avoidance cost of CCS based on the use of external fuel to achieve a constant heat load to the reboiler.
|
|
| 2. |
- Biermann, Max, 1989, et al.
(författare)
-
Partial capture from refineries through utilization of existing site energy systems
- 2021
-
Ingår i: 15th Greenhouse Gas Control Technologies Conference 2021, GHGT 2021. - : Elsevier BV.
-
Konferensbidrag (refereegranskat)abstract
- Many studies indicate that carbon capture and storage operations need to be ramped up in the coming decades to limit global warming to well-below 2°C. Partial CO2 capture from carbon-intensive industrial processes is a promising starting point for initial CO2 transport and storage infrastructure projects, such as the Norwegian full-chain CCS project “Northern Lights”, since specific capture cost (€/t CO2) for single-stack capture can be kept low compared to full capture from all, often less suitable stacks. This work highlights the importance of utilizing existing site energy systems to avoid significant increase in marginal abatement cost when moving from partial to full capture. A systematic and comprehensive techno-economic approach is applied that identifies a mix of heat supply sources with minimum cost based on a detailed analysis of available heat and capacity within the existing site energy system. Time-dependent variations are considered via multi-period, linear optimization. For single-stack capture from the hydrogen production unit (~0.5 Mt CO2 p.a.) of a Swedish refinery in the context of the current energy system, we find avoidance cost for the capture plant (liquefaction, ship transport, and storage excluded)of 42 €/t CO2-avoided that is predominantly driven by steam raised from available process heat in existing coolers (~6 €/t steam). For full capture from all major stacks (~1.4 Mt CO2 p.a.), the avoidance cost becomes twice as high (86 €/t CO2-avoided) due to heat supply from available heat and existing boiler capacity (combustion of natural gas) at costs of ~20€/t steam. The analysis shows that very few investments in new steam capacity are required, and thus, that the utilization of existing site energy systems is important for lowering capture cost significantly, and thus the whole-chain cost for early CCS projects.
|
|
| 3. |
- Eliasson, Åsa, 1993, et al.
(författare)
-
Efficient heat integration of industrial CO2 capture and district heating supply
- 2022
-
Ingår i: International Journal of Greenhouse Gas Control. - : Elsevier BV. - 1750-5836. ; 118
-
Tidskriftsartikel (refereegranskat)abstract
- Excess heat from industrial processes can be used for carbon capture and storage (CCS) as well as providing heat to a district heating network, leading to increased energy efficiency and reduction of on-site and/or off-site CO2 emissions. In this work, both options are assessed with respect to economic performance and potential reduction of CO2 emissions. The work includes a generic study based on five heat load curves for each of which three CO2 capture plant configurations were evaluated. The economic assessment indicates that the specific cost of capture ranges from 47-134 €/t CO2 depending on heat profile and capture plant configuration. Having excess heat available during a long period of the year, or having a high peak amount of heat, were shown to lead to low specific capture costs. The paper also includes results of a case study in which the methodology was applied to actual seasonal variations of excess heat for an integrated steel mill located in northern Sweden. Specific capture costs were estimated to 27-44 €/t CO2, and a 36% reduction of direct plant emissions can be achieved if the CO2 capture plant is prioritized for usage of the available excess heat
|
|
| 4. |
- Eliasson, Åsa, 1993, et al.
(författare)
-
Integration of Industrial CO2 Capture with Industrial District Heating Networks: A Refinery Case Study
- 2021
-
Ingår i: Short Papers from the 11th International Trondheim CCS Conference. - 2387-4295. - 9788253617145 ; , s. 197-201
-
Konferensbidrag (refereegranskat)abstract
- Industrial carbon capture and storage is recognized as an important technology to reach net zero emissions and mitigate global warming in accordance with the Paris agreement. Absorption-based carbon capture requires considerable amounts of low-grade heat, and a high degree of integration with the plant’s energy system is thus of high importance in order to achieve low operating costs for the capture plant. In this context, it is important to redefine what is commonly referred to as process “excess heat”. This work evaluates the impact of heat integration of a carbon capture plant with an existing refinery and two excess heat-powered district heating networks. The results show that a capture rate of ~60% of direct emissions at the refinery will consume all of the plant’s available residual heat. However, the results also indicate that a significant amount of heat can be recovered from the capture plant and exported for district heating supply purposes. Subsequent to capture plant integration, the potential district heating supply is 87 MW, compared to 100 MW in the reference case.
|
|
| 5. |
- Fahrman, Elin, 1995, et al.
(författare)
-
Integrating CO2 Absorption to a Batch-wise Production Process – A Case Study on a Smelter Plant in Northern Sweden
- 2021
-
Ingår i: Short Papers from the 11th International Trondheim CCS Conference. - 2387-4295. - 9788253617145 ; , s. 120-126
-
Konferensbidrag (refereegranskat)abstract
- This work presents results from an investigation of integration of carbon capture with a batch-wise operating process conducted through a case study on a large smelter plant located in northern Sweden with annual CO2 emissions of approximately 300 kt/a. Separate capture plants for the two major sources of emissions, Process I and Process II, were conducted using detailed, continuous flue gas property data. These two units together account for about 70% of the site’s total emissions. The plants were designed for a capture rate of 90% during peak CO2 flow. One of the objectives of the study was to investigate opportunities to operate the capture plant using excess heat sources available on site. The plant dynamics were characterized by studying the magnitude, duration, and frequency of the variations of the site steam flows, as well as the production cycle lengths of Process I and Process II. The results indicate that the present site energy system can cover 31 - 40% of the capture plant’s reboiler heat demand for capture from both Process I and Process II. This coverage increases to 54% for a future scenario. Neglecting the dynamics of the existing energy system only leads to a very small difference in heat demand coverage when both Process I and Process II are integrated with the carbon capture plant (31-40% with dynamics, and 31-42% without dynamics). However, when only the emissions from Process I are captured, the potential heat demand coverage for the existing energy system varies considerably (50% heat coverage accounting for dynamics compared to 100% without). Furthermore, for the future energy system scenario, the coverage of both units is 72% when dynamics are neglected compared to 54% with dynamics. These results clearly indicate the importance of considering dynamic operating characteristics in discontinuously operating processes. The smelter plant variations are characterized by time scales that are similar to the stabilization time of the carbon capture plant. The behaviour of the capture plant can thus not be fully characterized using a steady-state model (as used in this work), but this approach nevertheless provides an initial estimation of the design configuration and the share of heat demand which can be covered by the present process site energy system.
|
|
