WE-NET Home Page/Summary of Annual Reports 1997

8.4 Development of major auxiliary equipment

8.4.1 R&D Goals

8.4.1.1 Research objective

As a part of the hydrogen utilization technology to get superior environmental performance and extremely high thermal efficiency, we conduct the surveys and technology developments of the main auxiliary equipment of a hydrogen combustion turbine, and establish the basic technologies required for the development of a pilot plant which will be conducted in Phase II of the project

8.4.1.2 Scope of research.

The survey and research as well as the basic technology development which are necessary for the development of a pilot plant is implemented.

In this fiscal year, we reviewed the basic engineering requirements for designing a compact highly efficient cryogenic heat exchanger, super cooling tower and re-boiler condenser, and overall system of oxygen production.

In addition, we will perform conceptual design and study compactufication and structure-safety of high temperature heat exchanger for a hydrogen combustion turbine power plant as consequent assignment from the fiscal year of 1996.

8.4.2 Result in fiscal year of 1997

(1) Development of utilization of cryogenic from liquid hydrogen

1. Review of conceptual design
In overall system design for a 1000MW hydrogen combustion turbine power station, oxygen supply for one unit of air separation device has been changed to 59,000Nm³/h as resulting in four units air separation devices for a 1000MW power plant due to the review result.

Fig. 8-4-1 shows the overall flow diagram of a hydrogen combustion power system.

And efficiency of para-oltho hydrogen conversion catalyst was collected from 100% to 94.9% based upon the experimentally data, and then recovery cryogenic energy with hydrogen to air separation device is determined. Fig. 8-4-1 shows overall flow diagram of air separation device by introducing expander turbine to reduce energy consumption.

2.Study of specification of major equipment
As resulting from review of conceptual design, major equipment of heat exchangers as top condensers was re-studied in its specification.

Top condenser (plate fin type heat exchanger) in the oxygen production device selected in last fiscal year was reviewed in specification of size, and flow balamce. Size of the condenser was not changed so much.and Fig. 8-4-3 and Fig. 8-4-4 and 8-4-5 show flow diagram and equipment's sizing.
Other heat exchangers
Air separation device include main heat exchangers, subcoolers , oxygen vaporized device etc beside top condensers. In this fiscal year, study of re-boiler condenser and subcooler were carried out under the condition of using plate fin type of heat exchangers.
Re-boiler condenser is located between low pressure column and high pressure column, and condensation of nitrogen gas in high pressure column and vaporization of liquid oxygen in low pressure column is performed simultaneously at re-boiler. Subcooler is to promote cooling ability of air by nitrogengas from low-pressure column.
Table 8-4-1 and table 8-4-2 show design condition and Fig.8-4-6 and Fig. 8-4-7 show device overviews.

(2) Development of high temperature heat exchanger

After selecting the topping regenerative cycle as optimum cycle in fiscal year 1997,two re-entrusted manufacturers were studied by completion way.

Fig. 8-4-8shows flow diagram of the topping regenerative cycle and Fig. 8-4-9 shows the heat balance of high temperature heat exchangers.

For this R&D, number 14 and number 15 heat exchangers are objective items to conduct studies because of its high temperature of approximate 700°C and high pressure of 350 bar.

One of two conducted the study of downsizing of the exchangers to use the fin configuration and tubes pitch as a parameter.

Fig. 8-4-10 shows the basic plan of number 14 exchanger and Fig. 8-4-11 shows the one of the number15 exchanger.

Fig. 8-4-12 shows the panel tube configuration for number 14 exchanger and intermediate supports are located with constant distance in order to strengthen the support and protect vibration of the tubes.

Materials for the exchangers are subject to survey for steam oxidation attack and several alloys are to be studied in the future.

The other of two referred conventional heat recovery steam generators for gas combined cycle power plants.

As a result from fiscal year 1998 studies, number 14 and 15 exchangers show in Fig. 8-4-13 and Fig. 8-4-14 respectively.

Configuration of the exchangers are hanging structure like conventional boiler design to consider thermal expansion of tubes and supports., and spacers are hired in the center of the tubes and other consideration were put on omterface of gas buffles and tubes etc.

Fig. 8-4-15 to Fig. 8-4-18 show the out line of each portions.

8.4.3 Reseach plan for fiscal year 1998

As the final fiscal year of the phase one project, development of cryogenic technology and high temperature heat exchangers will be finished in next fiscal year. And conceptual design will be completed as summarizing feasibility of system and other engineering verification for the exchangers, And the Major Equipment Advisory Committee as following to the evaluation items in Table 8-4-3 will evaluate two competitive reentrusted manufacturer studies. One of two will be selected by the evaluation procedure as the optimum technology.