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## Commercial Experience of the CT-121 FGD Plant for 700 MW Shinko-Kobe Electric Power Plant #27 Yasuhiko Shimogama Kobe Steel 2 Nadahamahigashi-cho, Nada-ku, Kobe, Japan Hirokazu Yasuda Naohiro Kaji Fumiaki Tanaka Chiyoda Corporation 3-13 Moriya-cho, Kanagawa-ku, Yokohama, Japan David K. Harris Black & Veatch Corporation 11401 Lamar Avenue, Overland Park, Kansas, USA



### ABSTRACT Shinko-Kobe Electric Power Plant was designed as an "Urban Type Plant" which must meet stringent environmental control requirements, because this power plant is located in the center of the Kobe City. To maintain the quality of life of the citizens, Chiyoda Corporation was requested to provide process capabilities to meet very stringent environmental requirements. The CT-121 FGD process can provide superior SO 2 and particulate removal performance to meet the client’s requirements as demonstrated by our experience in existing CT-121 installations. This paper describes the commercial experience of the CT-121 plant for Shinko-Kobe Electric Power Plant from the following different perspectives.
 From operating experience: - Stable SO 2 removal efficiency of over 99 percent. - High SO 2 removal efficiency with low operating cost. - High particulate removal efficiency.  From construction experience: - Construction cost reduction by applying the panel construction method.2 In addition to the above, the relevance of CT-121 Kobe experience to North American applications is discussed from the following viewpoints.
 Accommodating a wide variety of fuels and inlet conditions.  Maximizing the results of an investment in FGD technology.  Avoiding costly particulate control modifications or upgrades.  Reducing project costs and cost variance through panel construction of the JBR.



### INTRODUCTION Shinko-Kobe Electric Power Plant is located in the center of Kobe City, which is the fifth largest city in Japan with a population of over one million, and is the largest IPP project in Japan. The CT-121 FGD process was requested to provide process capabilities which meet the unprecedented and stringent environmental requirements imposed by the site-specific condition. To maintain the quality of life of the citizens, Shinko-Kobe Electric Power Plant has set up a noble theme. The CT-121 must also play an important role to realize the theme through its design and construction.



### THEME OF SHINKO-KOBE ELECTRIC POWER PLANT Shinko-Kobe Electric Power Plant (coal fired power generation, 2 x 700MW) has been constructed as an "Urban Type Power Plant" under the theme of coexistence with the City. The No. 1 power plant was put into operation on April 1, 2002, and the No. 2 power plant is now under construction for commercial operation starting on April 1, 2004.3 Figure 1 illustrates the theme of Shinko-Kobe Electric Power Plant. Figure 1 Theme of Shinko-Kobe Electric Power Plant



### PROPOSITION REQUESTED OF THE CT-121 TO MAINTAIN QUALITY OF LIFE OF CITIZENS To achieve the noble theme and to maintain the quality of life of the citizens, Shinko-Kobe Power Plant has introduced the latest environmental technologies of the highest level from all fields including air pollution, water quality preservation, noise, vibration and odor prevention. In the field of air pollution control, the CT-121 can strongly boast its SO 2 and particulate removal capability to meet the client’s requirements. That is to say, it can realize a part of the theme established by Shinko-Kobe Electric Power Plant and can play an important role in an “Urban Type Power Plant”. The propositions requested of the CT-121 are summarized as follows:
 Stable SO 2 removal efficiency of over 99 percent.  High SO 2 removal efficiency with low operating cost.  High particulate removal efficiency. Urban Type Power Plant

Effective Use

of Energy Harmon y with Community Coexistence with the City4 

### PROPOSITIONS FROM THE OPERATING EXPERIENCE The No.1 FGD unit of the CT-121 installations for Shinko-Kobe Electric Power Plant, which is hereinafter referred to as “CT-121 Kobe,” has been operated for almost a year without any trouble. This chapter describes the operating experience of CT-121 Kobe. 

### Stable SO 2 

### Removal Efficiency of Over 99 Percent The outline of Shinko-Kobe Electric Power Plant and the basic design of the CT-121 Kobe are shown in Table 1 and Table 2, respectively.
Table 1 Outline of Shinko-Kobe Electric Power Plant Location Kobe City, Hyogo, Japan Output 700MW (×2) Fuel Coal (S in coal: 0.93 %, HHV: 10,400 Btu/lb) Boiler Once-through boiler Steam Turbine Condensing turbine Generator Synchronous generator Flue Gas Treatment ・ DeNOx System : SCR process

・ Dust collector : Low-low temperature ESP

・ DeSOx system : The CT-121 Process Construction Started June 1, 1999 Commercial Operation started April 1, 2002

Table 2 Design Basis and Major Equipment of CT-121 Design Condition
<Inlet> Flue Gas Coal fired boiler flue gas Gas Volume 1,395,000 scfm SO 2 concentration 740 ppm (O2=6 % dry) Particulate loading 0.0207 gr/scf (O2=6 % dry)
<Outlet> SO 2 removal efficiency 99 % (on an instantaneous basis) Particulate loading 0.00236 gr/scf (O2=6 % dry)5 Table 2 Design Basis and Major Equipment of CT-121 Design Condition

<Limestone> Purity 97 % Particle Size 90 % passing through 200 mesh screen <Gypsum> Purity More than 95 % Moisture Content Less than 10 % Major equipment of CT-121 Absorber (JBR) Rectangular type 75.5 ft(W)×75.5 ft(L)×50.2 ft(H) No. of agitators : 4 Gas to Gas Heater Non-leak type cyclic reheat GGH Flue Gas Fan Variable pitched axial blade fan Gypsum Separator Horizontal belt filter
The SO 2 removal efficiency of over 99 percent is the most stringent requirement for an IPP project with a coal-fired boiler in Japan. In addition, the CT-121 must meet other requirements as well, such as high particulate reduction and producing commercial grade gypsum.6 Figure 2 shows the results of SO 2 removal performance at various boiler loads.

This figure shows superior SO 2 removal efficiency of over 99 percent on an instantaneous basis in the cases of varying load and inlet SO 2 concentration. The CT-121 process is recognized as the pioneer of the limestone forced oxidation (LSFO) process. The CT-121 process uses a Jet Bubbling Reactor (JBR), which combines SO 2 absorption, forced oxidation reaction, neutralization reaction by limestone, and gypsum crystallization in one process vessel. Since these four reaction steps are performed simultaneously, the oxidation reaction of absorbed SO 2 proceeds very efficiently. Therefore, stable and higher SO 2 removal can be readily achieved due to a lack of any SO 2 backpressure in the JBR. This is the reason why the CT-121 can achieve high and stable SO 2 removal efficiency and maintain it under any circumstances. 

### High SO 2 

### Removal Efficiency with Low Operating Cost The CT-121 Kobe is designed for higher pH operation compared to the typical operating pH of other CT-121 installations. Achieving higher SO 2 removal efficiency by higher pH operation leads to the reduction of system pressure drop across the JBR, resulting in reduction of power consumption of flue gas fan. The following sections describe the comparison between the CT-121 Kobe and spray tower processes regarding the additional power consumption required to achieve 99 percent SO 2 removal efficiency, as well as the cost reduction by the higher pH operation. Figure 2: SO2 removal efficiency vs. various boiler loads

90 91 92 93 94 95 96 97 98 99 100

0 12 24 36 48 60 72 Operating time (h)SO2 removal efficiency (%)

250 300 350 400 450 500Inlet SO2 Concentration (ppm) Efficiency Inlet SO2

100% 75% 50% 30% Load indicating percentage7 Additional power consumption to achieve 99percent from 95 percent Figure 3 shows the additional power consumption to achieve 99 percent SO 2 removal efficiency compared with 95 percent SO 2 removal efficiency in the CT-121 and spray tower processes.

* 1. Power consumption related to SO 2 removal efficiency (CT-121: Flue gas fan and gas cooling pumps, spray tower process: flue gas fan and recirculating pumps) *2. Base 100 percent This figure shows our calculation results of the spray tower’s power consumption. The calculation base is “New Models for FGD Performance, Cost and Hazardous Sir Pollutant Removal” 1 published at the SO 2 Control Symposium in 1995. The figure illustrates that the CT-121 can achieve 99 percent SO 2 removal efficiency with only 26 percent additional power consumption. On the other hand, spray tower processes need almost 70 percent additional power consumption. This difference exists because the contact of gas to liquid by the jet bubbling mechanism is more efficient than spray tower processes. Moreover, CT-121 Kobe could reduce its operating power consumption by the higher pH operation. The details are shown in the next section. Figure 3: Additional power consumption to achieve 99% as SO2 removal efficiency

169

126
100 *2 100 *2

0 25 50 75 100 125 150 175 200

Spray tower CT-121Power index (%) *1 95% 99%8 Power reduction by the higher pH operation Power reduction in the CT-121 Kobe by higher pH operation is shown in Figure 4.

In this Figure, the bar on the left shows the operating power in typical pH operation (Base) and the bar on the right shows the operating power in the higher pH operation (1.0 higher than the typical pH) in the CT-121 Kobe. The CT-121 Kobe has successfully reduced the power consumption of flue gas fan by 16 percent through higher pH operation compared with the typical pH operation. The operating pH of the CT-121 is usually lower than spray tower processes by approximately 1.0~1.5. Moreover, the pH of the jet bubbling layer where SO 2 is absorbed is lower than the pH at the pH measuring location. So in that layer, limestone can be dissolved easily. From our operating results of the CT-121 in existing installations, we have confirmed that limestone stoichiometry is only slightly increased even in the higher pH operation. That is why we applied the higher pH operation in the CT-121 Kobe. As expected, gypsum quality of higher than 95 percent has been maintained. Figure 4: Power reduction by higher pH operation

84

50 55 60 65 70 75 80 85 90 95 100

Base Base+1.0 pH (-)Power reduction index (%)9 

### High Particulate Removal Efficiency One of the most important features of the CT-121 is its high particulate removal efficiency, which is superior to spray tower processes. Figure 5 shows the particulate removal performance of the CT-121 Kobe.

CT-121 Kobe can maintain stable high particulate removal efficiency at various inlet particulate loading rates (0 ~ 0.04 gr/scf). This superior particulate removal efficiency is attributed to the efficient contact of gas to liquid by the jet bubbling mechanism. The particulate loading at FGD outlet is approximately 0.0005 gr/scf or less, compared with the guaranteed outlet particulate loading of 0.002 gr/scf.



### REDUCTION OF CONSTRUCTION COST AND CONSTRUCTION WORK PERIOD In addition to the high performance, the Kobe project emphasized cost reduction, including minimization of design cost, specification review of the main equipment, and examination of the installation method. The CT-121 has been improved continuously from the viewpoint of cost reduction based on the technologies developed by Chiyoda Corporation. Figure 5: Particulate Loading at FGD inlet vs. Particulate Loading at FGD outlet

0.000 0.001 0.002 0.003

0.00 0.01 0.02 0.03 0.04 Inlet particulate loading (gr/scf, 6%O2)Outlet particulate loading(gr/scf, 6%O2) Guaranteed zone10 For example, cost reduction was realized by modifying the shape of the absorber as the gas throughput of the absorber was increased. The cylindrical structure was changed to a rectangular one, following the structure of the CT-121 for Haramachi Power Plant. Then, as a result of additional structural analysis, further progress was made in the design technique. In recent years, the rectangular-shape with combined-panel JBR, which is directly welded with the reinforcement pillars and beams, has become the standard for Chiyoda in Japan. This chapter describes the results of our efforts in reducing the construction work period and reducing the construction cost for the JBR by making the best use of the advantages of the combined-panel JBR through effective utilization of heavy construction machines and cranes. 

### Reduction of Construction Work Period The time required for the execution of the Kobe project was approximately three and one half years in total. This period includes design, manufacturing, construction, and commissioning. The duration of commissioning phase is not a process requirement, but contractual requirement. The scope of work includes not only desulfurization equipment (consisting of absorber, duct, mist eliminator, fan, belt filter, etc.), but also limestone storage equipment (including limestone powder silo and limestone powder receiving piping), the gypsum storage equipment (including gypsum silo, gypsum unloading machine, etc.) and the gypsum shipping equipment (including conveyor belt, ship loader, etc.). The gross weight of the equipment and apparatus used for this construction was approximately 4,000 tons. The items in the outline execution period were as follows.
Table 3 Project Execution Schedule Item 1998 1999 2000 2001 2002 1 Basic Design 2 Detail Design 3 Procurement 4 Shop Fabrication 5 Field Construction JBR-Assembly JBR-Flake lining JBR-Internal work 6 Commissioning Notes:
• The basic design was started when the kickoff meeting was held with the client.
• The foundation work is not included in the scope of work.
• The commissioning work includes BTG commissioning.11 Table 4 shows the remarkable reduction ratio in the work period of the absorber assembly compared to the conventional construction of 700 MW FGD with rectangular JBR. The Table also shows the total manday reduction ratio in the field construction.
Table 4 Comparison of Work Period and Reduction of Construction Mandays in Absorber Construction
Construction Item Kobe Conventional construction method for 700 MW Shell assembly period 70 % 100 % Flake lining period 80 % 100 % Internal work period 80 % 100 % Total construction mandays 85 % 100 % Note:
• The comparison is made based on actual construction cost data.
The reduction in the work period was achieved for each item and the labor reduction of 30 percent was achieved especially in the panel assembly steps where a new method of construction was adopted. This was achieved by the following factors:
 Utilization of marine transportation and adoption of the large panel installation method.  Increase in the prefabrication ratio.  Securing the internal work environment by completing the roof panel installation in the early stage. Since it was possible to unload items at a quay in the construction site, the side and roof panels of the absorber were manufactured in a factory and were divided into 15 large parts (for example, the size of one part was 28.9 ft × 74.5 ft × 3.9 ft, weighing 66,100 lb), thus increasing the prefabrication ratio considerably. Unloading of the parts was performed immediately before the side panel installation began without any loss of work period in the construction steps. In the conventional method of construction, frame assembly and side panel installation was repeated step by step. It took about 75 days for the above-mentioned work. On the other hand, in large-sized panel construction, panel installation was completed for only three days. It took only 40 days for panel installation including internal beams after the panel installation was started. After the completion of panel installation, the roof panel was put into place. In addition, work delays due to bad weather could be avoided by closing the roof so quickly. This has also contributed to the reduction of construction work period.12 Figure 6 shows the outline of absorber construction sequence of CT-121 Kobe. Figure 6: Progress of Absorber Construction

Lay down of the bottom plates Installation of the internal beam

Panel Installation (2 days after the panel installation started) Roof Panel Installation (40 days after the panel installation started)

Overview of FGD Plant The work period reduction was achieved compared with the past actual results in the flake lining and the internal works, which were performed after the shell assembly. The flake lining work is greatly dependent on the development of application technology. The spray13 method, which is often used overseas, is also established in Japan. The method is expected to be more effective for larger equipment. Additionally, the internal JBR decks are made of FRP. Considerable weight savings were achieved by use of FRP composite material of sandwiched structure. This savings contributed to the reduction of construction work volume. This FRP composite material has been used for airplanes and vessels for many years, especially in US and is also used in the aerospace field in recent years. It will continue to be used in a variety of fields as one of the state-of-the-art materials. 

### Reduction of Construction Cost The following three key goals were set for achieving the reduction of construction cost:  Material cost reduction.  Shop fabrication cost reduction.  Field construction cost reduction. The comparison of construction cost based on the conventional method of a 700 MW absorber is shown below.
Table 5 Comparison of Construction Cost for Absorber Assembly Item Kobe Conventional Rectangular Type Steel weight 86 % 100 % Shop fabrication cost 71 % 100 % Field construction cost 71 % 100 % Total assembly cost 67 % 100 % Notes:
• The comparison is made based on actual construction cost data.
• The percentages are shown based on the conventional rectangular type as 100 percent.
Firstly, as has been previously described, the greatest factor of material cost reduction was the adoption of the combined shell structure. The design of the combined shell structure allowed us to replace the separated side panels with the brace of a frame. It enabled the weight reduction of steel materials because the quantity and size of a frame component were reduced from the conventional ones, and the main frame could be used both as a beam and as a stage structure without any modification

. Secondly, as adopting the new construction method for large-size panels increased the prefabrication ratio, it was expected that the ratio of shop fabrication cost would increase.14 The overseas fabrication of the JBR was applied for the cost reduction of the shop fabrication cost due to the lower labor cost. However, risks such as quality deficiency from quick outsourcing were considered. Therefore, a subcontractor who carried out the design, fabrication and installation works in Japan for existing CT-121 installations and owns an overseas factory located in Indonesia 、 was selected. Cost reduction of 29 percent compared to the construction of the conventional rectangular type absorber could be achieved. Thirdly, the cost reduction of the field construction is discussed hereinafter. The main factor, which contributed to the field construction cost reduction, was the reduction of work period. Another factor was the minimization of unnecessary unloading and secondary drayage by controlling on-site delivery of products using the just-in-time delivery system. The cost reduction was achieved using all of the above-mentioned three key goals. The total reduction in the field construction cost reached 29 percent compared to the conventional rectangular type absorber. Finally, we conclude this chapter emphasizing that we could achieve an overall cost reduction of 33 percent in the absorber construction including the flake lining and internal works compared to the conventional cylindrical type absorber, although our discussion was limited only to the absorber assembly in this paper.



### RELEVANCE OF CT-121 KOBE EXPERIENCE TO NORTH AMERICAN APPLICATIONS In North America, Chiyoda Corporation has entered into an exclusive licensing agreement with Black & Veatch Corporation for the CT-121 FGD process. As utility and industrial operators face increased requirements for environmental controls, it is expected that the high SO 2 removal capability and the low operating cost of the CT-121 as demonstrated at Shinko-Kobe Electric Power Plant will allow North American users to achieve their objectives for environmental compliance while maintaining competitive costs of generation. 

### US Environmental Regulations Will Tighten Three bills were introduced to the 107th Congress proposing major reductions in air emissions from power generating facilities: Clear Skies Act of 2002, Clean Power Act and the Clean Air Planning Act. On February 12, 2003, Senator Jeffords re-introduced his Clean Power Act to Congress, and on February 27, 2003, President Bush's Clear Skies Act was re-introduced. These legislative proposals would transform the current air qualityregulatory framework from a command-and-control approach to a market based cap-andtrade scheme. Not only would this effect a major overhaul in the regulation of sulfur dioxide, nitrogen oxide, mercury, and possibly carbon dioxide emissions, but some of these15 legislative bills propose to transform or completely replace several major existing programs. Meanwhile, a significant and growing number of states have enacted their own, stringent air emission standards on one or more pollutants. While these federal legislative proposals are intended to bring more conformity and certainty to the current situation, it is important to keep in mind that to date, these new programs are only proposals, and nothing has been passed to negate the current emissions regulations already in effect. The US Environmental Protection Agency is under court order to promulgate Maximum Achievable Control Technology (MACT) regulations for no less than 33 different source categories of hazardous air pollutant emissions in the coming year, as well as a mercury MACT standard for coal and oil fired boilers by December 2003. The NOx SIP call is set to begin in May 2004, which will be closely followed by designation of non-attainment areas under the new ozone and PM2.5 ambient air quality standards. Under any new regulations requiring the installation of FGD equipment, cost of compliance will be a critical issue to be addressed. Moreover, under a cap-and-trade scheme as contemplated by Clear Skies and the Clean Power Act, the capability to achieve and maintain greater than 99 percent SO 2 removal, as demonstrated by CT-121 Kobe, can maximize the SO 2 reduction at every FGD installation and assist in reducing the overall cost of compliance. It is anticipated that emissions reductions resulting from by the Regional Haze Rule and the PM2.5 National Ambient Air Quality Standard would include additional particulate control at some facilities. The superior particulate removal performance in the CT-121 could allow those facilities equipped with the CT-121 for SO 2 control to avoid modifications or upgrades to particulate control equipment. 

### Fuel Flexibility Enhances Compliance Options CT-121 Kobe was designed for operation at 99 percent SO 2 removal for a one percent sulfur bituminous coal, analogous to an Eastern US low-sulfur coal. In the US, FGD installations have been completed for units firing much higher sulfur fuels, as high as 6 lb/MBtu or more. Nonetheless, process design modifications can accommodate high SO 2 removal requirements on a variety of fuels, and CT-121 has also been applied for high removal efficiency requirements on high sulfur applications. At Onahama Smelting and Refining Company, 99 percent SO 2 removal treating a gas stream from a sulfuric acid plant was guaranteed and achieved with an inlet concentration of 7,000 ppm SO 2 . In addition, 15 other applications guaranteed and achieve greater than 95 percent SO 2 reduction with an inlet SO 2 concentration greater than 2,000 ppm. The fuel flexibility afforded by CT-121 may allow the FGD installation to enhance an overall fuels strategy. As discussed previously, the efficiency of gas-liquid contact in the CT-121 allows the process to accommodate increased removal efficiency at a lower incremental power16 consumption compared to conventional spray towers. As a corollary benefit, CT-121 can achieve and maintain high and stable SO 2 removal under varying SO 2 inlet conditions. This results in a reduced operating margin being required to maintain compliance, allowing greater variations in coal quality while maintaining environmental compliance. 

### Reducing Construction Cost Risk Construction costs remain the single greatest risk contributor to cost overruns on FGD installation projects. Construction costs can escalate tremendously when the available construction labor resources are exceeded. If environmental retrofit projects proceed as expected, whether under Clear Skies, mercury MACT, or other programs, construction labor resources could be constrained. In the US as in Japan, maximum shop fabrication and assembly is the primary execution strategy to deal with site challenges and project resource limitations. Shop labor, combined with shop productivity rates and specialized equipment, produce work for 35 to 50 percent of the cost for the same activities performed in the field. Additional costs are incurred for shipping and erection of large components, but the net savings usually favors maximum shop fabrication. Many US fabricators have their shops in the Gulf Coast region where barge access permits greater weights (up to 200 tons) and greater physical dimensions than permitted for truckable modules (limited to 50 tons in most locations). In addition to the overall schedule savings afforded by panel construction of the JBR, this method can allow construction of the absorber module to be taken off the critical path. In doing so, the required labor resources can be levelized against construction of the new chimney (if required) or the limestone preparation system. Panel construction of the JBR can reduce project costs by maximizing shop fabrication, reducing the overall schedule, and levelizing labor requirements.



### CONCLUSIONS This paper describes our commercial experience of the CT-121 FGD Plant for 700 MW Shinko-Kobe Electric Power Plant. The operating and construction experiences are summarized as follows:
 The CT-121 can maintain stable SO 2 removal efficiency of over 99 percent on an instantaneous basis.  Higher pH operation allowed 99 percent SO 2 removal efficiency with only slight additional power consumption.  The particulate removal efficiency is superior to that of other spray tower processes.17  Applying the panel construction method results in the reduction of construction cost and reduction of work period. Application of the CT-121 capabilities and construction cost reduction methods in North America as demonstrated at Shinko-Kobe Electric Power Plant will allow North American users to achieve their objectives for environmental compliance while maintaining competitive costs of generation by:
 Accommodating a wide variety of fuels and inlet conditions.  Maximizing the results of an investment in FGD technology.  Avoiding costly particulate control modifications or upgrades.  Reducing project costs and cost variance through panel construction of the JBR.



### ACKNOWLEDGEMENTS The authors acknowledge the cooperation of Shinko-Kobe Electric Power Plant and Kobe Steel from the early design stage of CT-121 FGD throughout the construction and commissioning.



### REFERENCES
1. Rubin, E.S. et al, New Models for FGD Performance, Cost and Hazardous Air Pollutant Removal , 1995 SO 2 Control Symposium, FL, 1995
2. Akira Kumagai, et al, Features of the CT-121 System for Operating Cost Reduction, 1999 MEGA Symposium, Atlanta, 1999



### KEYWORDS
Black & Veatch Chiyoda Construction CT-121 Flue Gas Desulfurization (FGD) Kobe Particulate