Effective Adsorbents for Establishing Solids Looping as a Next Generation NG PCC Technology

To achieve the UK's ambitious target of reducing greenhouse gas emissions by 80% by 2050, it is widely accepted that from ca. 2030 Carbon Capture and Storage (CCS) needs to be fitted to both coal and natural gas fired power plants.

The flue gas characteristics of natural fired gas power plants, mostly operating in a combined cycle of gas turbine and steam turbine (NGCC), differ significantly from those from coal-fired power plants. Comparing to the flue gas of the same size coal-fired power plant, the flue gas of a NGCC power plant contains significantly lower CO2 (3-5 vs. 13-15%) and higher O2 concentrations (12-15 vs. 2-4%) and has ca. 50% higher flow rate, which make the separation of CO2 equally, if not more, challenging.

The most mature PCC technology, CO2 amine scrubbing, suffers from well-know problems of high energy penalty, oxidative solvent degradation and corrosion, large capture plant footprint and high rate of water consumption. A new generation of PCC technologies for NGCC power plants which overcome these drawbacks need to developed and demonstrated in the next 10 ~ 20 years in order for their commercialisation from ca. 2030. Solid adsorbents looping technology (SALT) is widely recognised as having the potential to be a viable next generation PCC technology for CO2 capture compared to the state-of-art amine scrubbing, offering potentially significantly improved process efficiency at much reduced energy penalty, lower capital and operational costs and smaller plant footprints.

The aim of this project is to overcome the performance barriers for implementing the two types of candidate adsorbent systems developed at Nottingham, namely the supported/immobilised polyamines and potassium-promoted co-precipitated sorbent system, in the solid looping technology specifically for NGCC power plants, which effectively integrates both materials and process development and related fundamental issues underpinning the technology development. The objectives are:

1. To overcome the following major specific challenges:
(a) To examine and enhance the oxidative and/or hydrolytic stability of supported/immobilised polyamine adsorbents and hence to identify efficient and cost-effective management strategies for spent materials.
(b) To optimise the formulation and preparation of the potassium-promoted co-precipitated sorbents for improved working capacity, reaction kinetics and regeneration behaviour at lower temperatures.
(c.) To gain comprehensive understanding of to what degree and how different flue gas conditions, particularly oxygen and moisture, can impact the overall performance of adsorbent materials and related techno-economic performance of a solid looping process.

2. To produce kilogram quantities of the optimum adsorbent materials and then demonstrate their performances over repeated adsorption/desorption cycles and to establish the optimal process thermodynamics in fluidized bed testing.

3. To investigate a novel rejuvenation strategy for oxidised polyethyleneimines involving low temperature hydrogenation.

4. To conduct techno-economic studies to assess the cost advantages of the solids looping technology for NGCC power plants over amine scrubbing based on the improved adsorbent performance and optimised process configuration achieved in the project.

The know-how acquired in this project will be of direct benefit to academics, CCS research community, power generation and energy industries, energy policy makers/regulators, environmental organisations and government departments such as DECC.

The successful delivery of the proposed project represents a major step forward in the development and demonstration of the novel and cost-effective Solids Adsorbents Looping CO2 capture technology for NGCC power stations.

In order to develop and assess the solid adsorbents looping technology for the CO2 capture of NGCC power stations for the first time across the world, the consortium brings together strong research expertise in Engineering, Chemistry, Materials and Energy Policy, and the supports of major industrial partners in power generation, engineering manufacturers/consultancies, and manufacturers of inorganic particles. This provides an ideal multidisciplinary environment for enhancing the skills set of the researchers working on the project. The employed RAs by the grant and any PhD students such as the one to be fully funded by the University of Nottingham involved with the project will gain much value-added transferable skills in materials synthesis, advanced characterisation techniques, fluidized bed testing and design, techno-economic assessment, problem posing and solving approaches and interpersonal skills through project meetings, progress reporting/presenting, working as part of the integrated research team across the whole consortium.

The project contributes directly to an effective technology to mitigate environmental and energy security concerns. The main stumbling block to the widespread implementation of Carbon Capture and Storage (CCS) in power plants is the energy cost associated with solvent regeneration in the most mature Post Combustion Capture (PCC) technology - amine absorption, which will become even greater when applied to a gas-fired power plant because of its flue gas characteristics (lower CO2 concentration, higher O2 concentration and higher flue gas flow rate compared to a similar size of coal-fired power plant). Hence, alternative PCC technologies for gas power plants need to be developed that have the potential to lower this energy penalty and also have lower capital and operating costs. With the proposed project, the consortium partners will develop and assess the solid adsorbents looping technology (SALT) as a novel, low-cost and high-performing PCC technology for carbon capture from natural gas-fired power plants to overcome the main drawbacks of amine absorption. The project will focus on not only the development and characterisation of novel, highly performing organic (amine-based) and inorganic (alkali-based) adsorbents but also the process development, optimisation and adsorption/regeneration strategies/testing of the adsorbent materials under gas-fired power plant flue gas conditions. The developed adsorbents and SALT process can be rapidly scaled up by industrial partners to speed up the technology transfer process. The development of SALT and its underline technologies will be of great interest to not only the industrial partners (see the letters of support attached from these companies) but also industrial companies outside the consortium such as RWE and Foster Wheeler which are one of the main power companies and the developers of Circulating Fluidized Bed technologies that are ideal technologies for the realisation of SALT in demonstration- and commercial-scales. Innovations in SALT can also bring about new job opportunities and UK export opportunities.

Regular project meetings with the academic partners, the industrial partners and the Advisory Board will be used to discuss future research and opportunities for timely scale-up and demonstration.

All investigators have a strong track record of publishing high-impact technical papers in international, peer reviewed journals, and presenting at international conferences and they will supervise the publications and co-author papers with the other researchers working on the project, giving plenary and keynote addresses at conferences and media interviews as appropriate.

Specific public engagement event is currently being planned for energy research at Nottingham, on the occasion of the grand opening of the Energy Technologies Research Institute building in 2012, through which this project would be showcased.