A boiler including one or more evaporators, an economizer, and a low-temperature heat exchanger. The economizer is located on a downstream side of the most downstream evaporator which is an evaporator at the most downstream side among the one or more evaporators. The low-temperature heat exchanger is located on the downstream side of the economizer, has an inlet for receiving water from the outside, and is configured to heat the water introduced from the inlet and sent to the economizer with the combustion gas.

A steam generator is provided. The steam generator has a combustion chamber having a peripheral wall formed at least partially from gas-proof, welded steam generator pipes, at least two additional inner walls formed at least partially from additional steam generator pipes which are arranged inside the combustion chamber. The inner walls are connected one behind the other on the flow medium side by an intermediate collector. The steam generator has a high service life and is reliable. The flow medium on the inlet of the inner wall upstream of the intermediate collector has a lower temperature than that of the flow medium on an inlet of the peripheral wall.

A steam generator is provided. The steam generator has a combustion chamber having a peripheral wall formed at least partially from gas-proof, welded steam generator pipes, at least two additional inner walls formed at least partially from additional steam generator pipes which are arranged inside the combustion chamber. The inner walls are connected one behind the other on the flow medium side by an intermediate collector. The steam generator has a high service life and is reliable. The flow medium on the inlet of the inner wall upstream of the intermediate collector has a lower temperature than that of the flow medium on an inlet of the peripheral wall.

The combustion and flue gas treatment system includes a furnace for combusting a fuel with an oxidizer generating a flue gas, ducting for the flue gas connected to a NO.sub.x removal unit and a SO.sub.x removal unit, and a recirculation line for recirculating a part of the flue gas back to the furnace. The SO.sub.x removal unit is located upstream of the NO.sub.x removal unit with reference to the flue gas flow. The recirculation line is connected to the ducting downstream the SO.sub.x removal unit.

The combustion and flue gas treatment system includes a furnace for combusting a fuel with an oxidizer generating a flue gas, ducting for the flue gas connected to a NO.sub.x removal unit and a SO.sub.x removal unit, and a recirculation line for recirculating a part of the flue gas back to the furnace. The SO.sub.x removal unit is located upstream of the NO.sub.x removal unit with reference to the flue gas flow. The recirculation line is connected to the ducting downstream the SO.sub.x removal unit.

A system reclaiming contaminated water includes a heat exchanger that receives the contaminated water and converts at least a portion of the contaminated water into steam and collects at least a portion of the contaminants within the heat exchanger. A thermal transfer fluid is heated by a heat exchanger is communication with a heat source. The heated fluid is circulated through the heat exchanger to heat the contaminated water. A steam engine is coupled to a generator, the steam engine receives the steam from the heat exchanger to drive the generator to provide power for the system. Steam exhausted from the steam engine is supplied to supplemental heat loads and then condensed in a modular condensing system. The collected contaminants are directed to an evaporation device to remove residual liquid.

In a power generation facility (10) wherein a fluidized bed combustion unit (12) produces steam to power a steam turbine generator (32), a heat recovery steam generator (20) produces steam for the steam turbine generator. Electrical power from the steam turbine generator is conducted to a motor (40) that drives and air compressor (36). The air compressor provides pressurized air back to the fluidized bed combustion unit (12) to promote fuel combustion. Flue gas from the heat recovery steam generator is selectively conducted to a CO2 capture unit (18) and then to a gas expander (42) that assists the motor in driving the air compressor (36). A heat exchanger (46) that is upstream of the CO2 Capture Unit and a heat exchanger (56) that is downstream of the CO2 Capture Unit and upstream of the air expander have thermal fluid sides that are connected in a closed circuit. The heat exchangers (46 and 56) convey heat away from the CO2 Capture Unit and provide heat to flue gas flowing to the gas expander to avoid icing conditions in the gas expander and acid condensation in the air emission stack.

In a power generation facility (10) wherein a fluidized bed combustion unit (12) produces steam to power a steam turbine generator (32), a heat recovery steam generator (20) produces steam for the steam turbine generator. Electrical power from the steam turbine generator is conducted to a motor (40) that drives and air compressor (36). The air compressor provides pressurized air back to the fluidized bed combustion unit (12) to promote fuel combustion. Flue gas from the heat recovery steam generator is selectively conducted to a CO2 capture unit (18) and then to a gas expander (42) that assists the motor in driving the air compressor (36). A heat exchanger (46) that is upstream of the CO2 Capture Unit and a heat exchanger (56) that is downstream of the CO2 Capture Unit and upstream of the air expander have thermal fluid sides that are connected in a closed circuit. The heat exchangers (46 and 56) convey heat away from the CO2 Capture Unit and provide heat to flue gas flowing to the gas expander to avoid icing conditions in the gas expander and acid condensation in the air emission stack.

The steam boiler system comprises a steam boiler comprising a burner and a chimney for exhausting flue gases, a feedwater line for leading feedwater to said steam boiler for producing steam, a steam line leading from said steam boiler to at least one application heat exchanger for feeding steam to said application heat exchanger, said application heat exchanger for heating an application fluid, and a condensate line leading away from said application heat exchanger for recuperating condensate from said application heat exchanger. An economizer heat exchanger is provided in said chimney, wherein at least one of said condensate return line and said feedwater line circulates through said economizer heat exchanger for allowing at least one of said condensate and said feedwater to be in heat exchange relationship with the flue gases for simultaneously cooling the flue gases while heating at least one of the condensate and the feedwater.

The steam boiler system comprises a steam boiler comprising a burner and a chimney for exhausting flue gases, a feedwater line for leading feedwater to said steam boiler for producing steam, a steam line leading from said steam boiler to at least one application heat exchanger for feeding steam to said application heat exchanger, said application heat exchanger for heating an application fluid, and a condensate line leading away from said application heat exchanger for recuperating condensate from said application heat exchanger. An economizer heat exchanger is provided in said chimney, wherein at least one of said condensate return line and said feedwater line circulates through said economizer heat exchanger for allowing at least one of said condensate and said feedwater to be in heat exchange relationship with the flue gases for simultaneously cooling the flue gases while heating at least one of the condensate and the feedwater.