Toru Ninomiya

Conceptual Design and Cooling Blade Development of 1700°C Class High-Temperature Gas Turbine

In this paper we describe the conceptual design and cooling blade development of a 1700°C-class high-temperature gas turbine in the ACRO-GT-2000 (Advanced Carbon Dioxide Recovery System of Closed-Cycle Gas Turbine Aiming 2000 K) project. In the ACRO-GT closed cycle power plant system, the thermal efficiency aimed at is more than 60% of the higher heating value of fuel (HHV). Because of the high thermal efficiency requirement, the 1700°C-class high-temperature gas turbine must be designed with the minimum amount of cooling and seal steam consumption. The hybrid cooling scheme, which is a combination of closed loop internal cooling and film ejection cooling, was chosen from among several cooling schemes. The elemental experiments and numerical studies, such as those on blade surface heat transfer, internal cooling channel heat transfer, and pressure loss and rotor coolant passage distribution flow phenomena, were conducted and the results were applied to the conceptual design advancement. As a result, the cooling steam consumption in the first stage nozzle and blade was reduced by about 40% compared with the previous design that was performed in the WE-NET (World Energy Network) Phase-I.

Effect of Pressure on Emission Characteristics in LBG-Fueled 1500°C-Class Gas Turbine

Developing integrated coal gasification combined cycle (IGCC) systems ensures cost-effective and environmentally sound options for supplying future power generation needs. In order to enhance thermal efficiency of IGCC and to reduce NO x emission, a 1500°C-class gas turbine combustor for IGCC was designed, tested, and the performance of the combustor was evaluated under pressurized conditions. The designed combustor had the following three characteristics: (1) in order to assure the stable combustion burning low-Btu gas (LBG), an auxiliary combustion chamber was installed at the entrance of the combustor; (2) to reduce fuel NO x emission that was produced from the ammonia (NH3) in the fuel, the rich-lean combustion method was introduced; and (3) to compensate for the declined cooling-air associated with the higher temperature of the gas turbine, the tested combustor was equipped with a dual-structure transition piece so that the cooling air in the transition piece can be recycled to cool down the combustor liner wall. As a result of combustor tests, it is confirmed that CO emission is less than 20 ppm, the conversion rate of NH3 which contains about 1000 ppm in the coal gasified fuel to NO x shows 40 percent or below, and the liner wall temperature remained below almost 850°C under high pressure (1.4 MPa), rated load condition.

Effect of Pressure on Combustion Characteristics in LBG–Fueled 1300°C–Class Gas Turbine

Developing integrated coal gasification combined cycle systems ensures that Japan will have cost–effective and environmentally sound options for supplying future power generation needs. The reduction of NOx emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in IGCC. The coal gasified fuel, which is produced in a coal gasifier of air–blown entrained–flow type has calorific value as low as 1/10 of natural gas. Furthermore the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine.The study is performed in 1300°C–class gas turbine combustor firing coal–gasified fuel in IGCC power generation systems. In the previous study the advanced rich–lean combustor of 150–MW class gas turbine was designed to hold stable combustion burning low–Btu gas fuel and to reduce fuel NOx emission that is produced from the ammonia in the fuel. By testing it under atmospheric pressure conditions, we have studied the effects of fuel parameters on combustor performances and listed the basic data for development applications. In this study, by testing it under pressurized conditions, we have obtained a very significant result through investigating the effect of pressure on combustion characteristics and wish to provide herein a summary of our findings.Copyright

Experimental Evaluation of a Low NOx LBG Combustor Using Bypass Air

A 150-MW, 1300°C (1573 K) class gas turbine combustor firing coal- gasified fuel has been designed. Main purpose of the present paper is first to estimate CO and NOx emissions, and second to discuss the low NOx combusion technology burning such a low-BTU gas. The full-scale, atmospheric-pressure combustion tests were conducted over a wide range of conditions using bypass air. The results are summarized as follows: (1) A designed combustor has an excellent combustion efficiency of 99.6 percent even when the calorific value of fuel drops to 650 kcal/m

Development of a Low-NOx LBG Combustor for Coal Gasification Combined Cycle Power Generation Systems

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to develop a high temperature gas turbine combustor using a low-BTU gas (LBG) which has high thermal efficiency and low emissions.In Japan a development program of the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, 1300°C class gas turbines will be developed. If the fuel gas cleaning system is a hot type, the coal gaseous fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel-NOx combustion technology will be one of the most important research subjects.This paper describes low fuel-NOx combustion technology for 1300°C class gas turbine combustors using coal gaseous low-BTU fuel as well as combustion characteristics and carbon monoxide emission characteristics.Combustion tests were conducted using a full-scale combustor used for the 150 MW gas turbine at the atmospheric pressure. Furthermore, high pressure combustion tests were conducted using a half-scale combustor used for the 1 50 MW gas turbine.Copyright

A Study on Low NOx Combustion in LBG-Fueled 1500°C-Class Gas Turbine

Developing integrated coal gasification combined cycle systems ensures cost-effective and environmentally sound options for supplying future power generation needs. The reduction of NOx emissions and increasing the inlet temperature of gas turbines are the most significant issues in gas turbine development in an Integrated Coal Gasification Combined Cycle (IGCC) power generation systems. The coal gasified fuel, which is produced in a coal gasifier of air-blown entrained-flow type has calorific value as low as 1/10 of natural gas. Furthermore the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine.This study is performed in a 1500°C-class gas turbine combustor firing low-Btu coal-gasified fuel in IGCC systems. An advanced rich-lean combustor of 150-MW class gas turbine was designed to hold stable combustion burning low-Btu gas and to reduce fuel NOx emission that is produced from the ammonia in the fuel. The main fuel and the combustion air is supplied into fuel-rich combustion chamber with strong swirl flow and make fuel-rich flame to decompose ammonia into intermediate reactants such as NHi and HCN. The secondary air is mixed with primary combustion gas dilatorily to suppress the oxidization of ammonia reactants in fuel-lean combustion chamber and to promote a reducing process to nitrogen.By testing it under atmospheric pressure conditions, the authors have obtained a very significant result through investigating the effect of combustor exit gas temperature on combustion characteristics. Since we have ascertained the excellent performance of the tested combustor through our extensive investigation, we wish to report on the results.Copyright

Design and Test of a Low-NOx Advanced Rich-Lean Combustor for LBG Fueled 1300°C-Class Gas Turbine

Research and development of an IGCC (Integrated Coal Gasification Combined Cycle) power generation system is being carried out as one of the advanced coal utilization technology in Japan. The coal gasified fuel, which is produced in a coal gasifier of air-blown entrained-flow type has calorific value as low as 1/10 of LNG. Furthermore, the fuel gas contains ammonia when a gas cleaning system is a hot type, and ammonia will be converted to nitrogen oxides in the combustion process of a gas turbine. The authors have designed and made an 1300°C-class advanced rich-lean combustor mainly designed for achieving low fuel-NOx combustion. By testing it under atmospheric pressure conditions, we have successfully reduced the NOx emissions (to 60 ppm corrected at 16 percent O2) by more than half the level previously achieved when the ammonia concentration was 1000 ppm. Combustion stability was adequate even when the calorific value of the fuel decreased to 2700 kJ/m3N.Copyright

Coal Gaseous Fueled, Low Fuel-NOx Gas Turbine Combustor

From the view point of future coal utilization technology for the thermal power generation systems, the coal gasification combined cycle system has drawn special interest recently. In the coal gasification combined cycle power generation system, it is necessary to develop a high temperature gas turbine combustor using a low–BTU gas (LBG) which has high thermal efficiency and low emissions.In Japan a development program on the coal gasification combined cycle power generation system has started in 1985 by the national government and Japanese electric companies. In this program, is planned to develop the 1300 °C class gas turbines. However, in the case of using a hot type fuel gas cleaning system, the coal gas fuel to be supplied to gas turbines will contain ammonia. Ammonia will be converted to nitric oxides in the combustion process in gas turbines. Therefore, low fuel–NOx combustion technology is one of the most important research subjects.This paper describes low fuel–NOx combustion technology for 1300 °C class gas turbine combustor using low BTU coal gas fuel.Authors have showed that the rich–lean combustion method is effective to decrease fuel–NOx (1). In general in rich–lean combustion method, the fuel–NOx decreases, as the primary zone becomes richer. But flameholding becomes very difficult in even rich primary zone. For this reason this combustor was designed to have a flameholder with pilot flame.Combustion tests were conducted by using a full scale combustor used in 150 MW gas turbine at the atmospheric pressure condition.Copyright

NOX reduction by multi stage air injection on pulverized coal combustion.

In order to reduce NOx and the ignition loss generated by the pulverized coal combustion, the optimum two stage combustion method and the multistage air injection method is investigated at the pulverized coal combustion test facility (standard load: 6.54 × 105 kcal/hr).The location of the air injection for the two stage combustion is suitable at the case of distance position from the burner for the NOx reduction, but suitable at the case of near the burner for the ignition loss reduction. So, the location of the air injection has the optimum point. However the optimum air injection point is used, if the air rate for two stage combustion is very high, the regeneration of NOx by the recombustion at the two stage air injection point is occured. The air rate for the two stage combustion has the upper limit.The multi-stage air injection method devide the air injection point for the two stage combustion to control the re-combustion at the case of the high air rate for the two stage combustion, and the regeneration of NOx. So, the NOx reduction rate of the multi-stage air injection method is larger than that of the two stage combustion . The air injection point and the distribution of the air injection rate for the multi-stage air injection method have the optimum values similar with the two stage combustion for both of the simultaneous reduction of NOx and ignition loss.If the injection point and the distribution of the injection air rate are optimized NOx and the ignition loss emission are lowered than that of the two stage combustion.