IGCC faces coal-antipathy in USA while Chinese projects progress

1 January 2008

The closing words of my report on last year's Gasification Technologies Conference (see Modern Power Systems, January 2007, pp 12-14) were that "it will need one or two ground-breaking ceremonies in the next twelve months to turn a lot of promise into reality." The original headline for this year's report had been "Mixed messages from Florida", based on the fact that in September, Southern Company had actually broken ground at its Stanton IGCC site, whereas shortly before the conference Tampa Electric Company (TECO) had announced that it would be shelving its Polk 6 IGCC project. The background to the latter decision, as explained in the announcement, was the current political and legislative situation in Florida, which was likely to put a cap on CO2 emissions on power plants in the state - as has already happened in California. Without any clarity on cost recovery for the CO2 capture and sequestration additions that might be required if the legislation went ahead, the TECO board has understandably shelved the project.

In fact the message from Florida became much clearer after the conference, when Southern Company announced its decision to terminate construction of the Stanton IGCC and instead to install a natural-gas-fired combined cycle unit. Against the background of three supercritical coal-fired units (total capacity 2650 MW) being denied permits in the state, the message is "no coal in Florida".

What the long term consequences of legislation, such as that in California and Florida, are likely to be, is unclear. In the short tem however delay in realising additional capacity at this scale is likely to increase the demand – and thus the price – for natural gas.

Layout of Duke Energy's proposed Edwardsport IGCC plant, Knox County, Indiana. This is the project most likely to become the first 630 MWe plant to be based on the GE–Bechtel reference plant design

Gasification in China

Meanwhile, China continues to be a centre for gasification projects and home-grown technology is certainly doing well there. The Opposed Multiple Burner (OMB) technology developed by the Institute for Clean Coal Technology in Shanghai, which was reported on in last year's conference review, has made impressive commercial progress, selling seven new licences in the past year. These are mostly for chemical applications, but it includes one 230 MW IGCC project, the Huadian Banshan plant, to be built at Hangzuou, which is scheduled to come on stream in 2010. This may be the first IGCC to be realised in China, but it is not the first syngas-fired gas turbine there. The Yankuang Cathay methanol plant in Shandong Province, which uses OMB gasification technology, already includes a Frame 6B gas turbine. The availability reported from this plant was also very impressive. Over the last eighteen months the average availability has been above 92%, without a spare gasifier.

Fast project realisation is also a feature of Chinese projects. The three year schedule for the Hangzhou IGCC mentioned above is an example, but there are others. SES have signed up for the gasification section of a methanol/DME plant in Yima with a schedule of under three years. This will use GTI's U-Gas fluid bed coal gasification technology, for which SES has a global exclusive licence. Construction of SES's first Chinese project for a methanol plant expansion at Hai Hua is substantially complete. SES has taken an equity position in both this and a second project, Golden Concord.

Other gasification technologies also continue to do well in China. GE report 11 new licences in the last three years, mostly for ammonia and methanol production. The first of Shell's many gasification projects in China have now been started up successfully. Siemens has seven SFG 500 MWt gasifiers for Chinese projects under construction. Commissioning of the first five reactors is due in 2009, with two more to follow in 2010.

Power generation projects

Coal-fired IGCC power generation plants have suffered similar setbacks to those encountered by many other coal-fired power projects. A quick count from an EPRI source indicated that some 16 announced supercritical pulverised coal (PC) plant projects with a combined capacity of 13000 MWe are not now going ahead.

Nonetheless some IGCC projects are continuing. The project most likely to become the first 630 MWe plant based on the GE–Bechtel reference plant design is Duke Energy's Edwardsport project in Indiana. Approval procedures are progressing successfully and unlike Florida, there is strong local support for the project. The project is located on a previously mined site and the necessary remediation work on site has begun. Construction completion is scheduled for 2011.

The US DOE-sponsored 275 MWe FutureGen project, which is to include underground storage of a least 1 000 000 t CO2/a, continues to be a focus of interest. The first inquiries for technology have already been issued. Site evaluation is nearly complete and the final decision between four competing locations, two in Texas and two in Illinois, will be made before the end of 2007.

An important issue on the siting selection is that the two states involved have offered to accept liabilities for the CO2 storage side of the project. If commercial coal-fired power generation projects, whether IGCC or PC, are to be required to provide capture and storage, then this is one of the issues that will require addressing on a general basis and not just for a single government-sponsored project. The other main issue is the question of how the additional cost of capture and storage is to be accommodated.

The most positive development in the IGCC world this year was the start up of Mitsubishi's 250 MWe air-blown demonstration unit at Nakoso in Japan (see Modern Power Systems, January 2006, pp 29-32). The first light up was in September, so that measurable operating results are not yet available.

On the other hand Nuon, in its presentation, announced that the Eemshaven Magnum project would be built in a phased manner, initially installing the gas turbines, and then adding gasification ability at a later stage (see also p 21). The gasification is due to come on stream about two years after the natural gas firing begins.

It is worth recording that the sponsors of all three postponed IGCC projects mentioned above, Nuon, TECO and Southern, have all reaffirmed that they consider IGCC to be the path forward for coal-based power.

Layout of Japan's Nakoso 250 MWe air blown IGCC demo plant, which has just started up 1 - gasifier; 2 - gas clean-up; 3 - turbine train; 4 - ASU

Industrial gasification projects

In his opening address Phil Amick, Chairman of the Gasification Technologies Council, voiced the view that "The industrial gasification marketplace, and by that I mean coal-to-chemicals, coal-to-liquids, fertilizers and even SNG projects, is a lot different than power. It's a commodity market, with storage and shipment, and with overseas competition. It's an international market ... there is no overhang of unused capacity in the chemical or fertilizer markets. New demand means new plants."

An important aspect in the US is that, although of course there is no difference in the environmental regulation of industrial plants, much of the other regulatory aspects of the power industry are absent. Furthermore CO2 capture is generally integral to the process, with part of the carbon contained in the product and the rest vented as pure CO2.

If the prospects for coal-fired power generation were overshadowed by this issue of carbon capture and storage, those for industrial projects were generally considered much more promising. In particular, a number of papers on production of substitute natural gas (SNG) had an optimistic tone. This was certainly influenced by the expectations of higher natural gas prices as a result of the delays in coal-fired power plants, although this was not explicitly mentioned in the presentations.

One of the largest SNG projects presented was Midwest SNG, which is being developed by ConocoPhillips, the second largest marketer of natural gas in the US, and Peabody, the largest coal company, to produce between 50 and 70 billion cubic feet (BSCF) of SNG per year. Others included the 20 BSCF Decatur plant in Illinois, which will be using Siemens gasifiers.

Gas- and coal-to-liquids (GtL and CtL) projects also received attention. John Baardson pointed out that co-firing biomass could substantially reduce the CO2 footprint of a CtL plant such as the Baard Energy Ohio River Clean Fuels Project – a strategy applicable to many other gasification-based projects.

Another interesting aspect was that the CtL presentations were not confined to the Fischer–Tropsch technology. Uhde presented a fluid-bed version of the (now) ExxonMobil methanol-to-gasoline (MTG) process being considered for a project in China. Topsoe presented its TIGAS direct gasoline synthesis process.

For a market such as the US, which currently imports gasoline and exports diesel, synthesis of gasoline could be much more attractive than diesel-orientated Fischer–Tropsch liquids.

Refining and oil sands applications

There was less emphasis on refining projects that in some previous years. Nonetheless two papers from Italian refinery IGCC operations provided examples of good reliability, availability and maintainability (RAM) performance.

The paper from the api Falconara plant reported availability over 90% (without any spare gasifier) for the fourth year running since a major improvement project. This project started in 2002 and included a new motor and rotor for the ASU air compressor and a new air intake filter for the gas turbine.

The paper from ISAB focussed on the expansion to the gasification plant to produce hydrogen, but also availability data on syngas in the range 86-96%, and 91-100.16% [sic], when including operation on auxiliary fuel.

The only new project discussed was that in the Fujian refinery in China, where approximately 100 t/h of deasphalted rock will be gasified in two Shell gasifiers (with one spare) to produce 80000 Nm3/h hydrogen, 280 MWe power and substantial quantities of steam for the refinery. The power plant includes two GE Frame 9E gas turbines and is already under construction with start-up scheduled for early 2009.

Little was heard this year from Canada. Oil sands projects there however are continuing. At the most advanced of these, the OPTI Long Lake project, the oil extraction facility has started, and the gasifiers will be started up in the coming year.

CO2 capture and storage

The session on CO2 capture and storage provided some interesting insights into the development work still required before carbon capture and storage can become a large-scale reality.

The session started with an excellent explanation for laymen, by Sally Benson of Stanford University, of how geologists assess the capture capacity of various underground structures. In the United States it is estimated that existing capacity will accommodate the current CO2 production for the next 200 years. Nonetheless "much more work is needed to increase confidence in theoretical and practical storage capacity estimates."

A discussion followed of the necessity for some major trunk pipelines to connect source regions with likely storage reservoirs.

Other presentations looked at the sensitivity of cost-of-capture to the degree-of-capture. This is important when setting regulatory targets. One study developed by WorleyParsons and ConocoPhillips found that plant performance begins to be seriously affected at about 50% capture. The point of diminishing returns on capital investment is at about 80%. Other studies seem to have produced similar results.

New technologies

Some of the most interesting technology developments were presented by the existing gasification technology suppliers. There have been market-place rumours for several years that Shell was developing a water quench variant of its coal gasification process. This is now official. The gas quench will remain to ensure a reliable passage through the sticky ash temperature regime, but the modified process provides a water saturated gas at low cost for raw gas shift applications such as when incorporating carbon capture.

Siemens is apparently moving in the opposite direction, but from a different starting point. The Germans are developing a waste heat steam generator after a partial water quench.

GE discussed the application of the recently acquired Stamet solids pump technology to dry feeding of low rank coals, though not in as much detail as many of the attendees might have liked. Looking at the current GE IGCC reference plant, with its combination of radiant and water quench cooling, it would appear that these three leading technologies are all converging towards a similar position, using dry feed with an optimised combination of steam generation and water quenching.

The most important development in the gas treating area was the demonstration of RTI's warm desulphurisation technology in a slip stream at the Eastman plant in Kingsport. The demonstration unit has been operated for over 3000 hours and has been able to achieve residual sulphur levels of between 5 and 20 ppm. While this is not yet the breakthrough for warm gas clean up, which could improve IGCC efficiencies by between 3 and 4 percentage points (Eastman's calculations), it is the first significant progress in this direction for many years. RTI and Eastman recognise that a full warm gas clean up must address other components such as mercury, arsenic and selenium as well as chlorides and ammonia and RTI has sorbents for these ready for pilot plant testing.

Biomass did not feature greatly in this year's conference. But one new technology did however stand out. Since tar production has plagued biomass gasification for a very long time, ECN and Dahlman from The Netherlands have developed a hot oil-based washing system, called OLGA, which reduces the tar content to a dew point of below 5°C. The first semi-commercial plant, rated at 4 MWt, was taken on stream in France last year and has met expectations.

DOE's Albany Laboratory has had a programme for improving the life of refractories in coal gasification service for some years now. In the last presentation of the conference, there was a report on some field trials with the new material. Although any improvements in corrosion resistance are only small, the results show a substantially improved resistance to spalling, which should be a considerable help in some plants.

Overshadowed by delays

Overall the conference was overshadowed by delays in implementation in the power sector, largely attributable to the current attitude in the USA towards all coal-based plant. Industrial applications will however continue, particularly in China.

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