NGCCs

In a Natural Gas Combined Cycle (NGCC) or an Integrated Gasification Combined Cycle (IGCC), the steam produced from the waste heat boiler is converted into extra electrical power in the steam turbines. Consequently, for hydrogen production, the steam use must be kept as low as possible. 

Supply side efficiency measures. Here we mean primarily increasing the efficiency of electricity production. Natural gas combined cycle power plants (NGCC) emit less C02 than single-cycle coal-fired power plants first, because natural gas emits about one-half the amount of C02 per fuel heating value than coal, and secondly, because the thermal efficiency of combined-cycle power plants is in the 45-50% range compared with the 35-38% range of single-cycle plants. In the... 

NEI NETPATH NFC NGCC NMR NOx NPP NRA NRC Development Nuclear Energy Institute Interactive code for modelling net geochemical reactions along a flow path Nuclear fuel cycle Natural gas combined cycle Nuclear magnetic resonance NO + N02 Nuclear power plant Nuclear reaction analysis National Research Council... 

NGCC/GTCC, Natural gas combined cycle (often termed gas-turbine combined cycle) PC, Pulverized-coal-fired power plant IGCC, Integrated gasification combined cycle, Oxy-fuel (PC boiler) plant. Flue-gas desulfurization and air particulate control is included in the total cost, but not in the separation unit cost. 

MM Btu typical industrial rate.seewww.eia.doe.gov 0.04-0.05/kWh typical industrial rate.seewww.eia.doe.gov 50% 65% future incremental efficiency of new plants Based on NGCC, coal and current grid at 0.75 kg/hr C02/kWe 400-600/ha/yr typical in U.S.. lower in developing nations or wastes 8-12 ton/hr/yr typical if farmed, 3-5ton/hr/yr if forestation or wastes 0.75-1.25/million Btu coal utility delivered see www.eia.doe.gov... 

The biomass gasification technology is highly suitable for retrofit to existing NGCC. 

Figure 11.5. Schematic representation of an NGCC power plant.

Integration of Hz/Syngas Production Technologies in NGCC Plants... 

The combustion of natural gas accounts for approximately 21% of the U.S. emission of C02. The majority of NGCC plants are not equipped with the C02 capture capability. Researchers in both academia and industry recognize the importance of controlling the C02 emissions and are working on developing technologies to effectively capture and sequestrate C02. 

The capture and sequestration of C02 reduces the efficiency and increases the capital cost of the NGCC plant significantly.6 Typically, -20% of the net power of the NGCC plant is lost in order to separate and sequestrate 90% of C02 emissions as shown in Figure 11.6. The addition of C02 capture units also results in -90% increase in the capital cost of the NGCC plant and -61% increase in the cost of... 

There are three main ways to capture C02 in the NGCC process post-combustion C02 capture, oxyfuel combustion, and precombustion C02 capture. 

The principle of post-combustion capture is shown in Figure 11.9. The exhaust gas from the NGCC plant is sent to the C02 capture unit, which typically utilizes chemical solvents such as amines or alcohols.7"13 Chemical absorption of C02 using solvent is preferred because of the low concentration of C02 ( 5%) and low pressure in the flue gas. The solvent loaded with C02 is regenerated typically in a reboiler using low-quality steam. The C02 released from the solvent can be sent to a sequestration plant. 

NexTech Materials, 323 NGCC. See natural gas, combined cycle (NGCC)... 

For the power production scenario, the hydrogen is co-fired in a turbine at a natural gas combined-cycle (NGCC) plant. Two options were examined ... 

NGCC Natural Gas Combined-Cycle PGM Platinum Group Metal... 

For the ZEPP system presented in Fig. 2.7 the allowable installed costs for the capture plant have been estimated to be in between 80 and 120M for a 1.4GWthermai input natural gas combined cycle (NGCC) plant. To meet the cost targets, an ITM based ZEPP power plant should have an electric efficiency of at least 52%. Capture ratios (carbon captured/carbon fed to the process) of 100% result in plant efficiencies lower than 50%. Capture ratios of the order of 85% are accompanied with plant efficiencies of about 52%. The allowable installed costs window is satisfied when the oxygen flux is at least 20 ml/cm min and the costs of the ITM tubes should be less than 1,500 /m. This clearly sets the targets for materials and turbine development in order for the system to be economically viable within the capture cost boundary conditions. 

Eklund HR, Sundkvist SG. A Development project of a future NGCC power process with C02-capture. 2004. 

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