Steam turbine system and combined cycle plant

An exhaust heat recovery plant comprising:

• a saturated steam generation portion that is configured to generate a saturated first steam;
• and
• an exhaust heat recovery boiler that is configured to generate a second steam by using heat of an exhaust gas,
• wherein the saturated steam generation portion is configured to generate, as the saturated first steam, a flash steam obtained by flashing a first water generated by the exhaust heat recovery boiler,
• wherein the exhaust heat recovery plant is configured to heat at least one of a second water flowing through a water supply system which is configured to supply the second water to the exhaust heat recovery boiler or a condensed water generated by flashing the first water, using a heat source other than the exhaust gas,
• wherein the exhaust heat recovery boiler includes an economizer that is configured to heat the second water with the exhaust gas,
• wherein the economizer is heating the second water heated by the heat source other than the exhaust gas with the exhaust gas,
• wherein the saturated steam generation portion is configured to generate the saturated first steam by flashing the second water heated by the economizer,
• wherein the exhaust heat recovery boiler includes a plurality of evaporators, and
• wherein the economizer supplies the second water to an evaporator arranged on the most downstream of a flow of the exhaust gas among the plurality of evaporators.

An exhaust heat recovery plant comprising:

• a saturated steam generation portion that is configured to generate a saturated first steam;
• and
• an exhaust heat recovery boiler that is configured to generate a second steam by using heat of an exhaust gas,
• wherein the saturated steam generation portion is configured to generate, as the saturated first steam, a flash steam obtained by flashing a first water generated by the exhaust heat recovery boiler,
• wherein the exhaust heat recovery plant is configured to heat at least one of a second water flowing through a water supply system which is configured to supply the second water to the exhaust heat recovery boiler or a condensed water generated by flashing the first water, using a heat source other than the exhaust gas,
• wherein the exhaust heat recovery boiler includes an economizer that is configured to heat the second water with the exhaust gas,
• wherein the economizer is heating the second water heated by the heat source other than the exhaust gas with the exhaust gas,
• wherein the saturated steam generation portion is configured to generate the saturated first steam by flashing the second water heated by the economizer,
• wherein the saturated steam generation portion is configured to feed the condensed water generated by flashing the first water to the economizer, and
• wherein the economizer is supplied by mixing the second water heated by the heat source other than the exhaust gas and the condensed water.