11,020 research outputs found
Process intensification for post combustion COâ capture with chemical absorption: a critical review
The concentration of COâ in the atmosphere is increasing rapidly. COâ emissions may have an impact on global climate change. Effective COâ emission abatement strategies such as carbon capture and storage (CCS) are required to combat this trend. Compared with pre-combustion carbon capture and oxy-fuel carbon capture approaches, post-combustion COâ capture (PCC) using solvent process is one of the most mature carbon capture technologies. There are two main barriers for the PCC process using solvent to be commercially deployed: (a) high capital cost; (b) high thermal efficiency penalty due to solvent regeneration. Applying process intensification (PI) technology into PCC with solvent process has the potential to significantly reduce capital costs compared with conventional technology using packed columns. This paper intends to evaluate different PI technologies for their suitability in PCC process. The study shows that rotating packed bed (RPB) absorber/stripper has attracted much interest due to its high mass transfer capability. Currently experimental studies on COâ capture using RPB are based on standalone absorber or stripper. Therefore a schematic process flow diagram of intensified PCC process is proposed so as to motivate other researches for possible optimal design, operation and control. To intensify heat transfer in reboiler, spinning disc technology is recommended. To replace cross heat exchanger in conventional PCC (with packed column) process, printed circuit heat exchanger will be preferred. Solvent selection for conventional PCC process has been studied extensively. However, it needs more studies for solvent selection in intensified PCC process. The authors also predicted research challenges in intensified PCC process and potential new breakthrough from different aspects
Steam cycle options for capture-ready power plants, retrofits and flexible operation with post-combustion CO2 capture
The energy penalty for postâcombustion carbon dioxide capture from fossilâfired power plants can
be greatly reduced â independently of the intrinsic heat of regeneration of the solvent used â by
effective thermodynamic integration with the power cycle. Yet expected changes in electricity
generation mix and the current immaturity of postâcombustion capture technology are likely to
make effective thermodynamic integration throughout the operating life of such plants a challenging
objective to achieve because of a requirement for extensive partâload operation and also for
matching to future technology improvements. Most previous published studies have, however,
focused on baseâload operation of the power cycle and the carbon dioxide capture plant and with
the assumption of a fixed technology.
For carbon dioxide captureâready plants the characteristics of the capture plant are also not known
when the plant is designed. The plant must operate initially without capture at a similar efficiency to
âstandardâ plants to be competitive. Captureâready plants then also need to be able to be retrofitted
with unknown improved solvents and to be capable of integration with a range of future solvents.
This study shows that future upgradability for postâcombustion capture systems can be facilitated by
appropriate steam turbine and steam cycle designs. In addition fossilâfired power plants with postcombustion
capture may need to be able to operate throughout their load range with the capture
unit byâpassed, or with intermediate solvent storage to avoid the additional emissions occurring
when the absorption column is byâpassed. Steam cycles with flexible steam turbines can be
adequately designed to accommodate for partâload operation with these novel operating conditions
and with rapid ramp rates.
Several approaches for effective captureâready pulverised coal and natural gas plants are also
described. These achieve identical performance before retrofit to a conventional plant with the
same steam conditions, but have the potential to perform well after capture retrofit with a wide
range of solvents, at the expense of only a small efficiency penalty compared to hypothetical plants
built with perfect foreknowledge of the solvent energy requirements. For existing plants that were
not made captureâready, and provided sufficient space is available and other physical limits are not
too constraining, ways to achieve effective thermodynamic integration are also discussed
MIT Space Engineering Research Center
The Space Engineering Research Center (SERC) at MIT, started in Jul. 1988, has completed two years of research. The Center is approaching the operational phase of its first testbed, is midway through the construction of a second testbed, and is in the design phase of a third. We presently have seven participating faculty, four participating staff members, ten graduate students, and numerous undergraduates. This report reviews the testbed programs, individual graduate research, other SERC activities not funded by the Center, interaction with non-MIT organizations, and SERC milestones. Published papers made possible by SERC funding are included at the end of the report
BIM semantic-enrichment for built heritage representation
In the built heritage context, BIM has shown difficulties in representing and managing the large and complex knowledge related to non-geometrical aspects of the heritage. Within this scope, this paper focuses on a domain-specific semantic-enrichment of BIM methodology, aimed at fulfilling semantic representation requirements of built heritage through Semantic Web technologies. To develop this semantic-enriched BIM approach, this research relies on the integration of a BIM environment with a knowledge base created through information ontologies. The result is knowledge base system - and a prototypal platform - that enhances semantic representation capabilities of BIM application to architectural heritage processes. It solves the issue of knowledge formalization in cultural heritage informative models, favouring a deeper comprehension and interpretation of all the building aspects. Its open structure allows future research to customize, scale and adapt the knowledge base different typologies of artefacts and heritage activities
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