209results about "Heat recovery" patented technology

A method of and a power plant for generating power by combusting carbonaceous fuel with substantially pure oxygen, and a method of modifying a process of generating power by combusting carbonaceous fuel from combusting the fuel with air to combusting the fuel with substantially pure oxygen. The methods include feeding substantially pure oxygen into a furnace for combusting fuel with the oxygen to produce exhaust gas including mainly carbon dioxide and water, recovering low-grade heat from the exhaust gas by using multiple exhaust gas coolers arranged in a downstream portion of the exhaust gas channel, wherein a first portion of the recovered low-grade heat is used for preheating feedwater; pressurizing a first portion of the exhaust gas in multiple exhaust gas compressors so as to produce liquid carbon dioxide, recycling a second portion of the exhaust gas to the furnace via an exhaust gas recycling channel, using a first portion of steam extracted from a steam turbine system to preheat feedwater, wherein the first portion of the recovered low-grade heat is more than 50% of the total amount of recovered low-grade heat, or larger than the first portion of the recovered low-grade heat in the air-fired process, allowing minimizing of the first portion of the extracted steam, and the expanding of a second portion of the extracted steam in at least one auxiliary steam turbine for driving at least one compressor or at least one pump of the power plant.

A process for cooling down a hot flue gas stream comprising water vapour and carbon dioxide, the process including: (a) heat exchange between the hot flue gas stream and a cooling water stream so that the hot flue gas stream is cooled to a cooled down gas stream at a temperature at which at least part of the water vapour therein has condensed and the cooling water stream increases in temperature; (b) combining the condensed water vapour and the cooling water stream to produce a combined water stream; (c) separation of the cooled down gas stream from the combined water stream; (d) cooling the combined water stream by contact with air from the atmosphere and by evaporation of a portion of the combined water stream; (e) using at least part of any non-evaporated and cooled water of the combined water stream as at least part of the cooling water stream for cooling the hot flue gas stream in step (a); and (f) storing any non-evaporated and cooled water of the combined water stream that is not used in step (e) and using the stored water later as at least part of the cooling water stream in step (a).

A method of reducing pollutants exhausted into the atmosphere from the combustion of fossil fuels. The disclosed process removes nitrogen from air for combustion, separates the solid combustion products from the gases and vapors and can capture the entire vapor / gas stream for sequestration leaving near-zero emissions. The invention produces up to three captured material streams. The first stream is contaminant-laden water containing SOx, residual NOx particulates and particulate-bound Hg and other trace contaminants. The second stream can be a low-volume flue gas stream containing N2 and O2 if CO2 purification is needed. The final product stream is a mixture comprising predominantly CO2 with smaller amounts of H2O, Ar, N2, O2, SOX, NOX, Hg, and other trace gases.

A gas cleaning system, which is operative for cleaning a process gas containing carbon dioxide and sulphur dioxide, comprises a combined cooling and cleaning system (16), and a CO2-absorber. The combined cooling and cleaning system (16) comprises a first gas-liquid contacting device (50) located upstream of the CO2-absorber and operative for cooling the process gas by means of a cooling liquid, and for absorbing into the cooling liquid sulphur dioxide of the process gas, such that a cooling liquid containing sulphate is obtained. The combined cooling and cleaning system (16) further comprises a second gas-liquid contacting device (94) located downstream of the CO2-absorber and operative for removing ammonia from the process gas, which has been treated in the CO2-absorber, by means of bringing the process gas containing ammonia into contact with the cooling liquid containing sulphate.