A heat recovery steam generator (HRSG) (10) including: an economizer (12) configured to heat a working fluid by extracting heat from a flow of flue gas (20). The HRSG includes a diluting fluid injector arrangement (60) configured to inject a diluting fluid (50) effective to dilute a concentration of a gaseous corrosive when compared to an undiluted concentration of the gaseous corrosive in the flow of flue gas. The HRSG also includes a preheater (18) configured to preheat the diluting fluid prior to injection.

A heat recovery steam generator (HRSG) (10) including: an economizer (12) configured to heat a working fluid by extracting heat from a flow of flue gas (20). The HRSG includes a diluting fluid injector arrangement (60) configured to inject a diluting fluid (50) effective to dilute a concentration of a gaseous corrosive when compared to an undiluted concentration of the gaseous corrosive in the flow of flue gas. The HRSG also includes a preheater (18) configured to preheat the diluting fluid prior to injection.

In a gasification apparatus, a gasification furnace (101) having an octagonal hollow cross-sectional shape, a heat exchanger (102) having a quadrangular hollow cross-sectional shape, and a connection portion (103) which connects an upper portion of the gasification furnace (101) to a lower portion of the heat exchanger (102) are provided, thereby simplifying structures and enhancing efficiencies can be achieved.

In a gasification apparatus, a gasification furnace (101) having an octagonal hollow cross-sectional shape, a heat exchanger (102) having a quadrangular hollow cross-sectional shape, and a connection portion (103) which connects an upper portion of the gasification furnace (101) to a lower portion of the heat exchanger (102) are provided, thereby simplifying structures and enhancing efficiencies can be achieved.

A boiler system (1) according to one aspect of the present invention includes a water electrolysis device (20) that electrolyzes electrolysis target water with electric power supplied from a natural energy power generation device (10) to generate hydrogen and oxygen, a boiler (30) that heats makeup water by combusting fuel to generate steam, a heat exchange device (40) that exchanges heat between the electrolysis target water and a heat medium, and a control device (70) having a cooling controller (71) that cools the electrolysis target water by supplying the makeup water as the heat medium to the heat exchange device when a preset cooling start condition is satisfied.

A boiler system (1) according to one aspect of the present invention includes a water electrolysis device (20) that electrolyzes electrolysis target water with electric power supplied from a natural energy power generation device (10) to generate hydrogen and oxygen, a boiler (30) that heats makeup water by combusting fuel to generate steam, a heat exchange device (40) that exchanges heat between the electrolysis target water and a heat medium, and a control device (70) having a cooling controller (71) that cools the electrolysis target water by supplying the makeup water as the heat medium to the heat exchange device when a preset cooling start condition is satisfied.