Materials-development projects for advanced ultra-supercritical(A-USC) power plants with steam temperatures of 700℃ and above have been performed in order to achieve high efficiency and low CO_2 emissions in Europe, ...Materials-development projects for advanced ultra-supercritical(A-USC) power plants with steam temperatures of 700℃ and above have been performed in order to achieve high efficiency and low CO_2 emissions in Europe, the US, Japan, and recently in China and India as well. These projects involve the replacement of martensitic 9%–12% Cr steels with nickel(Ni)-base alloys for the highest temperature boiler and turbine components in order to provide sufficient creep strength at 700℃ and above. To minimize the requirement for expensive Ni-base alloys, martensitic 9%–12% Cr steels can be applied to the next highest temperature components of an A-USC power plant, up to a maximum of 650℃. This paper comprehensively describes the research and development of Ni-base alloys and martensitic 9%–12% Cr steels for thick section boiler and turbine components of A-USC power plants, mainly focusing on the long-term creep-rupture strength of base metal and welded joints, strength loss in welded joints, creep-fatigue properties, and microstructure evolution during exposure at elevated temperatures.展开更多
At Olkaria （Kenya） geothermal energy has been used since 1981, to generate electricity and now there are currently 3 plants with a nominal capacity of 205 MW. Preliminary measurement and evaluation of possible mercu...At Olkaria （Kenya） geothermal energy has been used since 1981, to generate electricity and now there are currently 3 plants with a nominal capacity of 205 MW. Preliminary measurement and evaluation of possible mercury （Hg） emission from two plants has been investigated. Potential atmospheric Hg emission has been determined based on an existing model for estimating the transport of mercury along geothermal fluid flow streams as pertains to energy recovery and conversion from liquid dominated geothermal reservoirs. Hg concentrations, addition, retention and release rates were calculated at a number of locations in the geothermal power plants based on the plant operating parameters and steam flow process （turbine, condenser, non-condensable gas ejector, and cooling tower）. Potential Hg emission rates through plume range from 0.455 g/h to 2.17 g/h, or 10-30 mg/h per MWe. The emission per hour per MWe is 130-300 times lower compared to Hg levels reported for 88 MWe five operating geothermal power plants around Mt. Amiata area in Italy. These emissions are coupled with a release of 1.07 kg/h per MW of hydrogen sulphide （HzS）. The potential Hg release rates to the environment will depend greatly on the concentration of HzS in the system. Any higher HzS contents may reduce solubility of rig in the brine hence making it to be available in the steam. The volatile Hg may travel with the non-condensable gases as Hg vapour.展开更多
Developing countries as Mexico lack their own emission factors for thermoelectric power plants, so they have the need to develop them, considering specific operation conditions for each plant. This study develops spec...Developing countries as Mexico lack their own emission factors for thermoelectric power plants, so they have the need to develop them, considering specific operation conditions for each plant. This study develops specific emission factors in Mexico for： sulfur dioxide （SO2）, nitrogen oxides （NOx） and particles, for thermoelectric power plants that use fuel oil. This work was necessary due to the differences found between the measured and the calculated emissions, using emission factors of different agencies, such as, US-EPA （Environmental Protection Agency of the United States）, IPCC （Intergovernmental Panel on Climate Change）, and UK-NAEI （National Atmospheric Emissions Inventory of the United Kingdom）. The new emission factors were used to calculate the emissions of a thermoelectric power plant in Mexico. The comparisons between the measured and the calculated emissions （with the new emission factors） for 502, particles and NO2 were not significantly different （p 〉 0.05）.展开更多
文摘Materials-development projects for advanced ultra-supercritical(A-USC) power plants with steam temperatures of 700℃ and above have been performed in order to achieve high efficiency and low CO_2 emissions in Europe, the US, Japan, and recently in China and India as well. These projects involve the replacement of martensitic 9%–12% Cr steels with nickel(Ni)-base alloys for the highest temperature boiler and turbine components in order to provide sufficient creep strength at 700℃ and above. To minimize the requirement for expensive Ni-base alloys, martensitic 9%–12% Cr steels can be applied to the next highest temperature components of an A-USC power plant, up to a maximum of 650℃. This paper comprehensively describes the research and development of Ni-base alloys and martensitic 9%–12% Cr steels for thick section boiler and turbine components of A-USC power plants, mainly focusing on the long-term creep-rupture strength of base metal and welded joints, strength loss in welded joints, creep-fatigue properties, and microstructure evolution during exposure at elevated temperatures.
文摘At Olkaria （Kenya） geothermal energy has been used since 1981, to generate electricity and now there are currently 3 plants with a nominal capacity of 205 MW. Preliminary measurement and evaluation of possible mercury （Hg） emission from two plants has been investigated. Potential atmospheric Hg emission has been determined based on an existing model for estimating the transport of mercury along geothermal fluid flow streams as pertains to energy recovery and conversion from liquid dominated geothermal reservoirs. Hg concentrations, addition, retention and release rates were calculated at a number of locations in the geothermal power plants based on the plant operating parameters and steam flow process （turbine, condenser, non-condensable gas ejector, and cooling tower）. Potential Hg emission rates through plume range from 0.455 g/h to 2.17 g/h, or 10-30 mg/h per MWe. The emission per hour per MWe is 130-300 times lower compared to Hg levels reported for 88 MWe five operating geothermal power plants around Mt. Amiata area in Italy. These emissions are coupled with a release of 1.07 kg/h per MW of hydrogen sulphide （HzS）. The potential Hg release rates to the environment will depend greatly on the concentration of HzS in the system. Any higher HzS contents may reduce solubility of rig in the brine hence making it to be available in the steam. The volatile Hg may travel with the non-condensable gases as Hg vapour.
文摘Developing countries as Mexico lack their own emission factors for thermoelectric power plants, so they have the need to develop them, considering specific operation conditions for each plant. This study develops specific emission factors in Mexico for： sulfur dioxide （SO2）, nitrogen oxides （NOx） and particles, for thermoelectric power plants that use fuel oil. This work was necessary due to the differences found between the measured and the calculated emissions, using emission factors of different agencies, such as, US-EPA （Environmental Protection Agency of the United States）, IPCC （Intergovernmental Panel on Climate Change）, and UK-NAEI （National Atmospheric Emissions Inventory of the United Kingdom）. The new emission factors were used to calculate the emissions of a thermoelectric power plant in Mexico. The comparisons between the measured and the calculated emissions （with the new emission factors） for 502, particles and NO2 were not significantly different （p 〉 0.05）.
