An energy-saving gas supply boiler system, comprising: a steam boiler, a flue gas pipeline, a heat exchanger, a steam generator and an ejector. The steam boiler comprises a body, a combusting apparatus, a flue gas outlet, a water outlet and a high pressure steam outlet. The heat exchanger comprises a high temperature flue gas inlet, a medium temperature flue gas outlet, a cooling water inlet and a hot water outlet. Cooling water undergoes heat exchange with flue gas and flows out from the hot water outlet. The steam generator comprises a generator body, a hot water inlet and a low pressure steam outlet. The ejector comprises a high pressure steam inlet, a mixing steam outlet and a low pressure steam inlet. The high pressure steam inlet delivers high pressure steam to the ejector. The low pressure steam inlet delivers low pressure steam to the ejector.

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 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.

Systems and methods are disclosed for producing a superheated steam having a specified ratio of water vapor to combustion gases for injection into a well to enhance heavy oil production. Embodiments comprise indirect-contact steam generators and direct-contact steam generators.

The disclosure includes a water system that includes a feed water heat exchanger including a feed water heat exchanger above a water collection tank and a feed water heat exchanger/steam generator connected to the feed water heat exchanger. The feed water heat exchanger/steam generator includes a heat exchanger, coils, boiler burners, and emissions control. The water system includes a brine/waste water feed water heat exchanger positioned within brine/waste water tank enclosure, which includes a brine/waste water tank that is in fluidic connection with the feed water heat exchanger/steam generator. The water system includes a preheater in fluidic connection with the brine/waste water feed water heat exchanger, and a post-preheater heat exchanger enclosure including a post-preheater heat exchanger, post-preheater coils, post-preheater burner and post-preheater emissions control, the post-preheater heat exchanger in fluidic connection with the pre-heater. The water system includes a vapor removal device in fluidic connection with the post-preheater heat exchanger.

The disclosure includes a water system that includes a feed water heat exchanger including a feed water heat exchanger above a water collection tank and a feed water heat exchanger/steam generator connected to the feed water heat exchanger. The feed water heat exchanger/steam generator includes a heat exchanger, coils, boiler burners, and emissions control. The water system includes a brine/waste water feed water heat exchanger positioned within brine/waste water tank enclosure, which includes a brine/waste water tank that is in fluidic connection with the feed water heat exchanger/steam generator. The water system includes a preheater in fluidic connection with the brine/waste water feed water heat exchanger, and a post-preheater heat exchanger enclosure including a post-preheater heat exchanger, post-preheater coils, post-preheater burner and post-preheater emissions control, the post-preheater heat exchanger in fluidic connection with the pre-heater. The water system includes a vapor removal device in fluidic connection with the post-preheater heat exchanger.

The present application provides a method of adjusting a feedwater mass flow rate to maintain a constant steam temperature in an evaporator section. The method may include the steps of determining a change in a number of operational parameters, predicting a change in steam temperature based on the number of operational parameters, combining the predicted changes in steam temperature, determining a feedforward signal based on dynamically offsetting the combined predicted changes in steam temperature, and changing the mass flow rate of feedwater based on the feedforward signal.

A condensing heat recovery steam generator (cHRSG) includes a main stack for an exhaust hot gas main flow, a bypass stack for allowing a fraction of exhaust hot gas to bypass the exhaust hot gas main flow, and a heat pump. The cHRSG includes a primary water circuit, a secondary water circuit, and a tertiary water circuit. The cHRSG additionally includes a feedwater line, a first heat exchanger for providing heat exchange between the feedwater line and the secondary water circuit, and a second heat exchanger for providing heat exchange between the primary water circuit and the tertiary water circuit. In the cHRSG, latent heat is partially recovered from said exhaust hot gas circulating in the bypass stack through the second heat exchanger and additional heat is extracted in the tertiary water circuit by said heat pump, contributing to a preheating performed in a preheater of the primary water circuit.

A condensing heat recovery steam generator (cHRSG) includes a main stack for an exhaust hot gas main flow, a bypass stack for allowing a fraction of exhaust hot gas to bypass the exhaust hot gas main flow, and a heat pump. The cHRSG includes a primary water circuit, a secondary water circuit, and a tertiary water circuit. The cHRSG additionally includes a feedwater line, a first heat exchanger for providing heat exchange between the feedwater line and the secondary water circuit, and a second heat exchanger for providing heat exchange between the primary water circuit and the tertiary water circuit. In the cHRSG, latent heat is partially recovered from said exhaust hot gas circulating in the bypass stack through the second heat exchanger and additional heat is extracted in the tertiary water circuit by said heat pump, contributing to a preheating performed in a preheater of the primary water circuit.

A small supercritical once-through steam generator (OTSG) includes a radiant section with a furnace coil, and a convection section downstream of the radiant section that includes a superheater which is fluidically connected to the furnace coil. Optionally, the OTSG is devoid of a steam separator. An economizer can also be included downstream of the superheater. Supercritical steam can be generated using the OTSG, for use, among other things, in enhanced oil recovery applications.