Clean Coal Technologies - What roadmap for R&D

Clean Coal Technologies - What roadmap for R&D
SIXTH INTERNATIONAL CONFERENCE ON CLEAN COAL TECHNOLOGIES CCT2013 Clean Coal Technologies - What roadmap for R&D Ibrahim Gulyurtlu 12-16 MAY 2013, THESSALONIKI GREECE

Introduction CO2 considerations Coal utilisation technologies and Research areas for further development CO2 sequestration options in the long-term Some examples Programmes of US, Japan , and Europe Future concepts of power plants 9. Conclusions

Introduction

Coal continues to be the most abundant fossil fuel in the world but its wider use, particularly in developed countries heavily relies on technological developments for clean coal utilization in the energy market. Clean coal technologies (CCTs) developed in the last 40 years have been developed with the objective being deployed reduce the environmental consequences of the use of coal with particular attention on SO2, NOx, particulate matter and very recently on mercury.

Clean coal technologies (CCTs) developed in the last 40 years have been developed with the objective being deployed reduce the environmental consequences of the use of coal with particular attention on SO2, NOx, particulate matter and very recently on mercury. Short-term objective is basically to ensure that the existing fleet of power plants respect with the present and emerging regulations through cost-effective measures to have the most adequate environmental control.

Roadmap objectives, scope and structure, in IEA document on technology roadmap, were summarised in three principle ways with the aims to reduce emissions of CO2 from coal-fired power plants, in addition to improved demand-side energy efficiency: Deploy and further develop high efficiency and low emissions (HELE) coal technologies, i.e. use more efficient technology and continue to develop higher-efficiency conversion processes. Deploy CCS; recent demonstration projects show that CCS is technically viable and, in fact, essential to achieving long-term CO2 reduction targets. Switch to lower-carbon fuels or to non-fossil technologies as a means of reducing generation from coal.

However, facts about the present situation could be summed up as: − Technologies presently in operation for clean coal utilisation do really not meet the requirements for near-zero emissions or carbon management − The strategy employed by far for incremental improvements are not adequate to meet future requirements − Based on the strategy mentioned above, the policy applied up to now has involved adding on new equipment to existing plants to meet incremental improvements but this is generally a complex & costly procedure.

It is required to implement policies to make the transition to new technologies most effective and successful because − 60% of available U.S. capacity years old while in Europe, it is even higher for older fleet of power stations fired with coal and the situation in Japan is not much different. In countries with large consumption of coal for power like China, India new fleet is getting in operation but the technologies used are not suitable for efficient carbon management. − It is essential to get new technologies on the commercial stage in the next years to be able to substitute retiring power stations. − This transition must be accompanied without any disruptions in meeting the demand for power.

Coal reserves by region and type

Electricity generation from different sources

It is clear that the future of coal utilisation depends on the issue of CO2 is resolved in a cost effective manner for coal to be a vaible alternative. One aspect that is also highly important for the future is that any new technology developed should be able to deal with any type of coal and not specific to the nature of coal used. The current technologies are very much dependent on the nature of coal.

CO2 considerations

With human-related activities currently producing about 27 billion tonnes of CO2 emissions each year world-wide, it’s important to know not just how much CO2 can be captured using CCS, but for how long it will remain in storage. While any CO2 captured will remain stored indefinitely (?), estimates indicate CCS could capture and store the equivalent of between 70 and 450 years of man’s current global annual CO2 emissions. European Technology Platform for Zero Emission Fossil Fuel Power Plants (ZEP)

Source: IPCC (2007)

Source: National CO2 Emissions from Fossil-Fuel Burning, Cement Manufacture, and Gas Flaring: Emissions by Country

Other industrial processes e.g. fuels, chemicals, plastics, etc Carbon capture and compression To the electricity grid Sequetration -Capture Coal fired plant Gas fired plant Industry e.g. cement Storage Low carbon energy Oil to Industry Coal and biomass Transport Gas Injection Imperial College London/ Grantham Institute for Climate Change Saline aquifer Gas field Oil field Enhanced Oil Recovery

Options that include CO2-enhanced oil recovery and CO2-enhanced coal bed methane production, are particularly attractive because injection costs are offset by increased fossil fuel production.

Geological Storage Option Global Capacity Gtonne† CO2 As a proportion of total emissions 2000 to 2050 Depleted oil and gas fields 920 45% Unminable coal seams >15 >1% Deep saline reservoirs 400-10,000 20-500% The issue is that not all storage locations are close to the sources of CO2 emissions IEA publication

In the global transition desired to have a fully low-carbon economy, the Carbon Capture and Storage (CCS) technology has emerged, in recent years, the key way to achieve a desirable equilibrium between rising demand for fossil fuels for energy and the objective of reducing the greenhouse gas emissions. There is a great doubt that this aim to control the global temperature can be achieved. This is because the use of CCS as a large scale technology that could be employed commercially feasible for large scale deployment is put in question by many report. EU has already considered CCS not of the first priorities of further R,D &D.

The International Panel on Climate Change (IPCC) states that “Retrofitting existing plants with CO2 capture is expected to lead to higher costs and significantly reduced overall efficiencies than for newly built power plants with capture. The cost disadvantage of retrofitting may be reduced in the case of some relatively new and highly efficient existing plants or where a plant is substantially upgraded and built.” Most other studies agree with these conclusions. The main reasons are: Higher investments Shorter lifespan Efficiency penalty Standstill cost

For EU, the aim for the future is low carbon energy mix. EU has encouraged projects that could advance CCS from research projects to commercial demonstration projects with the objective of reducing cost, showing the safe geological storage of CO2, build on the knowledge and then pass this information with low-risk to investors. There have been considerable efforts to take the leading role on CCS development, all the demonstration projects funded by EU with complete CCS are located outside EU and even the promising suffer delays because of: Lack of business case Public awareness and acceptance Legal framework CO2 storage and infrastructure International cooperation

At present, CCS-equipped power plants could not produce electricity at costs that would make them profitable. This is because the cost of avoiding CO2 emissions using the current CCS technology is higher than the price paid for emitting CO2. The first CCS demonstration projects would operate in the red oval in the chart (right) and face a ‘financing gap’ of at least € 25 - € 55 per tonne CO2. It is estimated that with continuous technological improvements, the costs can be halved by This should ensure that CCS plants can in the future operate within commercially feasible parameters in an environment governed by a robust CO2 price (blue oval in the chart). EU publication

Coal utilisation Technologies and Research areas for further development

Issues What are the next steps with existing technologies What are the new technologies that could offer the optimised carbon management as performance capabilities could vary depending on application

Technologies presently utilised are not the most suited to face the future for our energy needs. They are based on up to 100 year-old concept improved over the years with add-on equipment and retrofitting to mostly address the environmental issues as they emerged. The existing technology was conceived to produce power to satisfy the rapidly industralisation of the Western world without too much concern to be ultra clean and to minimise greenhouse gas emissions such as CO2. new integrated system designs.

There are several potential paths to satisfy the long-term need for near-zero emission coal plants. Advanced combustion technology can use pure oxygen instead of air, thus making it easier to capture CO2. Gasification could lead to producing several end products such as electricity and transportation fuels and could handle flexibility in the fuel available. There are also for exploration the hybrid concepts combining combustion and gasification or making simultaneous use of power generation options such as fuel cells and combustion turbines, thus achieving high system efficiencies with very much reduced greenhouse gas emissions..

Emissions Control - Existing Plants Current technology could handle − Meeting existing regulations for NOx, PM, Hg, and by-product, however targets for using fresh water use my need to be re-evaluated Further technology requirements for improvement − Low-NOx combustion, low-cost catalysts, improved gas filtration and electrostatic separation, sorbent systems, multi-pollutant controls, dry cooling

Projects are underway for advanced environmental control technology and ancillary systems in the following areas: A) advanced NOx emissions control, B) mercury emissions control, C) particulate-matter emission control, D) coal utilization by-products, E) air quality research, and F) energy-water interface. Field demonstrations (utilizing up to 600 MW scale plants) are being carried out in the areas of innovative NOx, mercury and particulate control technologies as well as exploring opportunities for by-product utilization.

(USA roadmap for existing plants)

Current situation regarding emissions Roadmap technology publication of IEA

Advanced Combustion Technology Needs for which further R&D required - Cofiring, CFB (circulating fluid-bed) scale-up, Advanced boiler tube & steam turbine materials, Coal-oxygen combustion, Oxygen “carriers, Sensors & controls

Combustion technology needs are focused on three areas: advances that allow the effective use of existing plant assets (e.g., use of expert system techniques to improve emissions control; repowering technology to increase plant capacity, increase efficiency, and meet environmental requirements), advances to current plant concepts that will bridge to future plants, (e.g., ultra-supercritical steam to achieve higher efficiency), and future plant designs that have near-zero emissions including CO2.

Fuel flexibility and ultra-low NOx combustion are near-term objectives to enhance existing plant capability and performance. The capability to achieve operation with ultra-supercritical steam allows for increased plant efficiency. This capability will benefit plants built in 2010 and be available for integration in future near-zero emission plant concepts. Nitrogen-free combustion includes innovative concepts that include oxygen combustion and concepts that utilize chemical oxygen carriers.

CO2 intensity factors and fuel consumption values

The share of supercritical and ultrasupercritical capacity in major coal consuming countries

Roadmap technology publication of IEA

Future emissions levels expected with more advanced system Roadmap technology publication of IEA

Advanced Gasification Technology Needs for which further R&D required More efficient, lower cost gasifier designs (transport & others), Improved refractory materials, Air separation, More efficient & reliable feed systems

Integrated gasification combined cycle (IGCC) plants are the cleanest coal-based power systems available today and represents an effective means of capturing carbon dioxide for sequestration. The capital cost and reliability, availability and maintainability (RAM) of gasification processes are two key drivers in determining the commercial deployment of gasification technology.

IGCC could become a dominant technology in the power industry because of the following advantages: • Ability to handle almost any carbonaceous feedstock; • Ability to efficiently clean up product gas to achieve near-zero emissions of criteria pollutants, particulates, and mercury at substantially lower costs and higher efficiencies; • Flexibility to divert some syngas to uses other than turbine fuel for load following applications; • High efficiency because of the use of both gas turbine and steam turbine cycles; • Ability to cost effectively recover CO2 for sequestration, if required; • Ability to produce pure H2, if desired; • Greater than 50% reduction in the production of solid by-products; and, • Substantial reduction in water usage and consumption. Gary J. Stiegel, et. Al. NETL

Integrated Gasification Combined Cycle (IGCC) Roadmap technology publication of IEA

The major IGCC projects in the world Spain Holland USA USA JAPAN 250 MW Nakoso DEMO PLANT Presentation by Yoshikazu IKAI, Japan Coal Energy Centre

Integrated Gasification Fuel Cell Roadmap technology publication of IEA

Gasifier concepts are being investigated to lower the plant capital cost. Higher throughput designs; improved refractory life; the development of low-cost, reliable dry feed technology; and increased carbon conversion (98% target) are projected to contribute approximately 10% reduction in plant cost and approximately 5 percentage point increase in plant efficiency. Advanced air separation technology is projected to contribute a 5-7% reduction in the capital cost. The next generation air separation technologies require efficient thermal integration with the gasifier and the energy conversion technology (e.g., gas turbine).

Clean Coal Technologies - What roadmap for R&D Gas Cleaning
Technology Needs for which further R&D required Multi-pollutant control, Filter materials & systems, Regenerable sorbents, Sensors & instrumentation

Gas cleaning basically removes gas-phase contaminants and particulates to avoid corrosion, erosion or deposition in downstream energy conversion equipment and involves both environmental and process considerations. They are particularly stringent for coal-fired power plants. In future coal-fired systems, equipment can include combustion turbines, fuel cells, catalytic reactors to convert syngas to fuels, separations technologies for capturing CO2 or separating H2, and heat transfer equipment.

Gas cleaning involves many pollutants and any cleaning process has to be specific for the downstream unit operations to be employed. The requirements will differ for reliable operation of membrane separation technology, fuel cells, turbines, and other component designs. Representative requirements for fuels or chemicals production include total sulfur <60 ppb, total halide < 10 ppb, NOx < 100 ppb as well as specifications for other trace chemicals.

The approach for gaseous contaminant control is usually to employ sorbents. Sorbent performance, cost, regenerability and attrition resistance are common barriers. One of the challenges is how to design a system to meet the multi-pollutant control needs that is simple, low cost and reliable. The design of the gas cleaning system have to integrate well both process control and operation procedures – e.g. compatibility in operating temperature and pressure transients during turndown, start-up or shut-down.

Syngas Utilization for Power and Fuels Technology Needs for which further R&D required Fuels synthesis reactors, Syngas combustion, Fuel cells, Fuel-flexible turbines, Hybrid fuel cell-turbine systems, Hydrogen combustion, Air separation, Hydrogen separation

Gasification is used as part of the process in a new concept of coal-based power plants in which the syngas produced can be employed for power generation, for the production of liquid fuels, hydrogen, and chemicals as well as processing heat. In order to develop this concept to be one of the future options to generate energy it is imperative that the overall energy plant efficiency and costs meet competetive targets in comparison with other alternative energy production methods.

For this reason, progress over existing technology is needed to develop innovative processes for obtaining these products. It is required to define R,D &D programs: to develop gas separation technologies (e.g. hydrogen) and power generation technologies (e.g. solid oxide fuel cells, hydrogen turbines, oxygen-fired gas turbines).

Some examples

Oxy-combustion is one of the most promising near-term technologies enabling carbon capture and storage (CCS) because it is based on proven, reliable, commercially available technologies that reduce risk and, hence, allow near-term ( ) commercialization.

Oxy-combustion system of pulverised coal combustion plant

Circulating Fluidised Bed Systems are particularly well suited to oxy-combustion because of the fuel flexibility and better temperature control through particle recycling which can then reduce the flue gas recycling

In an oxygen-fired CFB system, with the proper amount of recirculated gas, the furnace conditions could be very similar to air firing using the appropriate systems that can be designed to have the same flue gas flow to coal flow ratio as with air firing and the same volumetric fraction of oxygen in the flue gas leaving the bed as that of the air-fired case.

Furthermore, a critical advantage for oxygen-fired CFB type furnaces is the capability to reduce flue gas flow for a given coal input, by minimizing the recirculated flue gas flow, while maintaining the furnace temperature.

With an oxygen-fired CFB, a recycling loop of solid materials is used, by adjusting the heat pick up, to control the furnace temperature at an optimum operation level for combustion efficiency without any potential risk of agglomeration.

One of the principal drivers for oxy-fuel technology is near zero emissions primarily in terms of CO2, but also other pollutants like oxides of nitrogen (NOx), oxides of sulphur (SOx), and particulates. The oxy-fuel process in the form examined here is based on the familiar steam power cycle. The combustion takes place in an O2–CO2–H2O atmosphere, moderating the furnace temperatures by flue gas recycling, leading to similar furnace and boiler designs compared with existing air-fired PF units. However, the subsequent flue gas treatment requires adaptations.

Some aspects of this technology remain to be addressed such as: ( in the next years) The part load behavior Safety aspects related to O2/CO2 containing enclosure Material risks concerning the heating of almost pure oxygen coming from ASU before being mixed to recycle stream The implementation of a 700ºC steam cycle Demonstration projects with fully integrated CO2 sequestration ENCAP project

One of the most immediate solutions to implement to reduce CO2 levels in power plants could involve the application of co-combustion of coal with biomass as biomass fuels are considered zero-CO2. A project entitled as “COPOWER” was funded by the Commission was undertaken to identify the synergy between coal of different origins and several biomass material. This is also a way of achieving clean coal application by ensuring that the two or more fuels could combine favourably during the combustion to reduce emissions and minimise problems associated with ashes. This then leads to more efficient and less costly plant operation

Pressure and Temperature Fluctuations Observed with Biofuels Relatively stable fuel feed rates were achieved. Combustion of MBM, OC and SP => bed agglomeration problems. Dense bed zone T < 800ºC ( ºC) => Preventing Bed agglomeration for MBM, OC and SP mono-combustion (Na, K). Wood pellets temperature and pressure profiles were very stable during combustion.

Vertical profiles of local mean temperature in Duisburg boiler

Average CO emissions at Chalmers boiler 5 10 15 20 25 30 coal coal + sludge + MBM sludge wood 2004 2005 2006 gas conc. [mg/Nm 3 at 6% O 2 ]

NOX Emissions - INETI Ex: fuel-N conversion decreased from 8 to 2 % increasing MBM from 0 to 25 %wt in the fuel mixture. During monocombustion of biomass fuels the fuel-N conversion to NO seems to increase probably due to higher air excess used and lower char inventory to promote NO heterogeneous reduction. NOX decrease during co-combustion of all biomass materials, independently of biomass N content. During co-combustion the fuel-N conversion to NOX decreased with the increase of biomass share in the mixture up to 25% wt. Biomass fuels released higher fractions of fuel-N as NH3 in the riser that possibly react with NO formed, reducing it to N2 through the known DeNOX mechanism.

Comparison of captured sulphur and limestone dosing (Ca dosing in the form of CaCO3 in excess of the Ca input with the fuel)

Hg retention in ashes Hg in Polish coal is 0.11 mg/kg whilst that of straw pellet is mg/kg Cl was high in both fuels = 0.3 % Small addition of straw, decreased Hg entered with fuel, adsorption on ashes was significant (SP – Straw Pellets) Amounts of Hg, S content and levels of unburned carbon in ashes influence the Hg retention

The effect of co-firing coal and sewage sludges on alkali related deposits in a 12 MW CFB KCl (g) is liable to induce deposition and subsequent corrosion of super heaters. Co-firing of a chlorine rich bituminous coal with straw pellets gives rise to a KCl(g)-level of ppm. This should be compared with the theoratical level of 65 ppm, which would be the case if all potassium in the fuel formed KCl. Adding sewage sludges to the fuel-mix brings the KCl(g)-level further down to practically zero. The deposition rate is lowered by co-firing with sewage sludge. Ash properties such as sulphur and alumino silicate content of coal and sludge have a dramatic effect on KCl-formation.

CO2 sequestration options in the long-term

The use of CO2 for synthetic fuel production or as feedstock in chemical processes and biotechnological applications or for the manufacture of other products is an area of R&D for the next years for an effective CO2 sequestration. This is an area in which most effort should be devoted to effectively deal with CO2 issue.

JAPANESE VISION

(USA roadmap for the future)

EU concept for the future

Future concepts of power plants

The future concept of integration of power generation and synthetic fuel production and utilisation in other applications

The Integrated power plant concept for the future that could be modified to include the use of CO2 as feedstock for many potential applications like synthetic fuel production, in chemical processs, etc. Presentation by Yoshikazu IKAI, Japan Coal Energy Centre (JCEC)

Conclusions

Coal will continue to be a valued resource to significantly contributing to energy production provided that clean coal technologies address to environmental challenges, Existing technologies make incremental improvements to emissions of most pollutants but are not equipped to meet the requirement near zero emissions and carbon management, Advanced technologies critical for coal utilisation with effective carbon management have been identified but their full introduction in major coal using countries will be over a period of 40 years provided outstanding technical issues are resolved in the next 20 years. This depends on the level of funding R&DD activities

Achieving cost and environmental goals requires maintaining significant investments in coal R & D in the next 20 years, The future CO2 sequestration should be based more on the utilisation of CO2 as feedstock for many different applications as alternative to underground storage, Demonstration projects are required before fully commercialisation of new technologies with CO2 sequestration, Coal is at a crossroad to be able to remain a viable energy source in the next 40 years. It has to consolidate its position in the next 30 years to meet challenges from other resources. Do not be put off by what President Obama said “So if somebody wants to build a coal-powered plant, they can. It’s just that it will bankrupt them because they’re going to be charged a huge sum for all that greenhouse gas that’s being emitted

Thank you for your attention
Do not be afraid of pressure. Remember that pressure is what turns a lump of coal into diamond Thank you for your attention

Clean Coal Technologies - What roadmap for R&D

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