Amine-based Process Research Articles

Amine versus ammonia absorption of CO2 as a measure of reducing GHG emission: a critical analysis

Carbon dioxide (CO2), one of the green house gases (GHGs) is well known for more than a century. Its emission from the combustion of fossil fuels in addition to other industrial sources is adversely affecting the climate on earth. Climate change is emerging as a risk all over the world that has generated public concern. Estimates have indicated that power production contributes to the tune of 70% of the total CO2 released into the atmosphere from fossil fuel combustion worldwide. Capturing and securely storing CO2 from the global combustion systems thus constitutes an important and achievable target. A legion of researchers have thus far developed absorbents to remove CO2 from combustion facilities that are currently recognized globally as most effective. The cost of capturing CO2 can be reduced by finding a low-cost solvent that can minimize energy requirements, equipment size, and corrosion. Monoethanolamine is being used for removing CO2 from the exhaust streams and is a subject inculcated over a period of about last 80 odd years. Host of such other amines are being investigated and put into practice. However, commercializations of such operating plants for capturing CO2 from power plants in the world are few and far between. On the other hand, aqueous ammonia is the other chemical solvent for capturing CO2 that has proven experimentally to be more effective than amine-based processes. This communication aims at critically elucidating relative merits and demerits of ammonia and amine-based CO2 capture options from the exhausts of coal fired thermal power plants (TPPs). It includes the life cycle CO2 emissions for both the processes. Finally, it is estimated that a total emission of about 152 Mt CO2-equivalent could occur after use of 100 Mt ammonium bicarbonate (NH4HCO3) as synthetic N-fertilizer that is about 50% of the total CO2 captured (315 Mt) for producing the fertilizer, NH4HCO3. Clearly, this estimate demonstrates that the synthetic N-fertilizer, NH4HCO3, produced by NH3 scrubbing of CO2 from fossil fuel (e.g., coal) fired TPP could have a significant beneficial environmental impact so far as GHG emission is concerned.

Chilled ammonia process for CO2 capture

Abstract The Chilled Ammonia Process (CAP) can be applied to capture CO2 from flue gases exhausted from coal-fired boilers and natural gas combined cycle (NGCC) systems, as well as a wide variety of industrial applications. Initial tests conducted at the We Energies Pleasant Prairie Power Plant indicate that CAP can absorb CO2 using regenerated ionic solution on a continuous basis. The We Energies facility is designed to capture over 35 tonnes/day of CO2 at design rates. The facility was engineered, installed, and is being operated as a co-operative effort between Alstom (the process supplier) who engineered and constructed the pilot; EPRI (including 37 funders) who is conducting data collection and process evaluation; and We Energies who is providing operating utilities and is serving as the site host. The CAP is a solvent-based regenerable process that uses an aqueous ammonium solution to capture CO2 by forming ammonium bicarbonate. The bicarbonate is subsequently heated to drive off the CO2 with the resulting carbonate returned to the CO2 absorption system for re-use. Anticipated advantages of the CAP over an amine-based process include: Lower energy for regeneration Regeneration at pressure Ability to offset LP steam consumption with reject heat (Not tested at We Energies) Cooling to minimize ammonia penetration from the absorber. Results from the initial operation of the CAP process at the We Energies site are presented in this paper.

Desulfurization of syngas in a transport reactor

AbstractDuring gasification, sulfur present in carbonaceous materials is converted into reduced sulfur species, such as H2S and COS. These sulfur species are conventionally removed from syngas by catalytic hydrolysis of COS into H2S, followed by scrubbing of H2S with liquid‐phase amine systems. Amine‐based processes are subject to equipment corrosion, foaming, amine‐solution degradation, and evaporation, and require extensive wastewater treatment. As a result, this sulfur removal technology is complex, capitalintensive, and expensive. Furthermore, this conventional technology requires the syngas be cooled to nearly ambient temperatures, thus wasting valuable energy.New emerging technologies for sulfur removal from syngas use regenerable sorbents, primarily based on ZnO. Recent advances in sorbent technology allow sulfur species to be removed from syngas over a wide temperature range (260° to 760° C), making it an attractive alternative for a wide variety of applications, including power generation, chemical production, and fuel cells. This sorbent technology has advanced to the point that syngas desulfurization can be carried out in both fixed‐and fluidized‐bed reactors, depending upon process design needs. Additional applications of this technology in desulfurization of natural gas and removal of sulfur species from a syngas generated from gasification of black liquor were investigated.