Method and device for preparing hydrogen by using fuel

The invention discloses a method and a device for preparing hydrogen by using fuel, and the method comprises the following steps: placing iron or iron oxide in an air reactor fluidized bed; reacting with introduced air to obtain Fe2O3; separating by a separator; feeding the separated Fe2O3 in a fuel reactor; feeding solid fuel in the fuel reactor by a spiral feeder if the solid fuel is used; carrying out gasification reaction with water vapour to generate synthesis gas; generating carbon dioxide and water vapour by a reduction reaction in which synthesis gas or solid fuel reacts with Fe2O3; obtaining clean carbon dioxide after condensation; reducing Fe2O3 to FeO or Fe; feeding FeO or Fe in a hydrogen production reactor fluidized bed; generating hydrogen by reacting FeO or Fe with water vapour; oxidizing FeO or Fe to Fe3O4; separating by the separator; discharging the separated hydrogen from the upper end of the separator; returning the separated Fe3O4 in an air reactor fluidized bed for ...

Method and device for producing hydrogen and separating CO2 based on iron or iron oxide

The invention discloses a method and a device for producing hydrogen and separating CO2 based on iron or an iron oxide. The method comprises the following steps: putting the iron or the iron oxide in an air reactor fluidized bed, reacting the iron or the iron oxide with infused air to obtain Fe2O3, discharging the air separated by a separator from the upper end of the separator, causing the separated Fe2O3 to enter a fuel reactor fluidized bed, causing a solid fuel to enter the fuel reactor fluidized bed by a screw feeder, reacting the solid fuel with infused water vapor to generate a synthesis gas, subjecting the Fe2O3 and the synthesis gas or the fuel to a reduction reaction to generate carbon dioxide, reducing the Fe2O3 to FeO or Fe and overflowing to a hydrogen producing reactor, reacting the FeO or the Fe in the hydrogen producing reactor with the water vapor to generate the hydrogen, oxidizing the FeO or the Fe to be the Fe3O4, discharging the hydrogen gas separated by the separator ...

Modeling and virtual simulating method for integrated coal gasification combined cycling air separating system

A method for modeling and simulating an air separation system of an integral gasification combined cycle power plant comprises the following steps: building up an accurate mathematical model of a rectifying tower according to mass balance, energy balance, gas-liquid phase balance, molecular normalization equation and physical property equations set of each tower tray; and carrying out simulation experiment for the air separation system, including the cold-state startup process of the rectifying tower and the operation under variable working conditions, so as to study the dynamic operating characteristics of the rectifying tower, as well as the dynamic, static and coupling relations among the input, the output and the disturbance variables of the system. The method is considerably helpful for further understanding the operating characteristics of the air separation system, setting a control strategy for the air separation system and optimizing the operation. Moreover, the method can bring ...

Heat and power cogeneration energy-saving device and method for supplying heat by using direct waste heat of air-cooling unit

The invention provides a heat and power cogeneration energy-saving and method for supplying heat by using direct waste heat of an air-cooling unit. The energy-saving device comprises a steam turbine, a deaerator, an air-cooling tower and a waste-heat recycling hot-water heater, wherein, a waste steam outlet of the steam turbine is connected with the air-cooling tower through a steam exhaust cylinder; the waste-heat recycling hot-water heater comprises an absorption heat pump and a heat exchanger, a steam inlet of the absorption heat pump is connected with an steam extraction opening of the steam turbine, and a water inlet end of the absorption heat pump is connected with a water returning end of a hot water pipe network; the waste steam discharged into the air-cooling tower from the steamturbine is partially or totally transferred to the absorption heat pump, is condensed into water through the absorption heat pump and then is transferred to a water storage tank of the air-cooling tower ...

Oxygen carrier gasifying combustion method for loading oxygen and device

The invention discloses an oxygen carrying gasification combustion method with an oxygen carrier as well as relevant apparatus; the method is characterized in that the oxygen carrier is arranged inside an air reactor fluidized bed; if fluidized air is fed, oxysome reacts with oxygen in the air before high-value metal oxide is heated to obtain; then, the oxide will be separated through a two-stage separator; the high-temperature oxygen denuded air, which is separated, is exhausted out of the upper-end of the separator; the separated oxygen carrier goes through a returning dipleg to enter a mixing and gasification chamber; in a circulation fluidized bed in the air reactor, an oxygen carrying reaction happens between the oxygen carrier and oxygen in the air: The oxygen carrier from the reaction flows into the dipleg after being separated by the two-stage separator, so that the oxygen carrier and the fuel can together enter the gasification chamber below the fuel reactor fluidized bed; in the ...

Coordination control method for integral coal gasification combined circulation power station

The invention puts forward a coordinated control method for an integrated coal gasification combined cycle power plant, aiming at a characteristic that the time constant of each equipment of the controlled object in the integrated coal gasification combined cycle power plant has great difference. The method adopts a cascade stratified control system structure, and is provided with an upper-layered main controller, namely, a coordination controller, and a lower-layered sub controller, namely, comprising a gasification island sub controller and a power island sub controller, wherein, the main controller is used for the calculation of a main control command and then sends to the lower-layered sub controller for the control of corresponding equipments, the lower-layered sub controller is alsoin charge of the regulation of other main controlled variables in the system; the control method coordinates the running of each equipment of the power plant gasification island and the power island,and ...

Method and device for preparing hydrogen by using fuel

The invention discloses a method and a device for preparing hydrogen by using fuel, and the method comprises the following steps: placing iron or iron oxide in an air reactor fluidized bed; reacting with introduced air to obtain Fe2O3; separating by a separator; feeding the separated Fe2O3 in a fuel reactor; feeding solid fuel in the fuel reactor by a spiral feeder if the solid fuel is used; carrying out gasification reaction with water vapour to generate synthesis gas; generating carbon dioxide and water vapour by a reduction reaction in which synthesis gas or solid fuel reacts with Fe2O3; obtaining clean carbon dioxide after condensation; reducing Fe2O3 to FeO or Fe; feeding FeO or Fe in a hydrogen production reactor fluidized bed; generating hydrogen by reacting FeO or Fe with water vapour; oxidizing FeO or Fe to Fe3O4; separating by the separator; discharging the separated hydrogen from the upper end of the separator; returning the separated Fe3O4 in an air reactor fluidized bed for ...

Gasifying stove forecasting type PID control method

Cogeneration energy-saving device and method using residual heat of direct air-cooling unit to supply heat

The invention relates to cogeneration energy-saving device and method using the residual heat of a direct air-cooling unit to supply heat. The device comprises a turbine, a deaerator and an air cooling tower and also comprises a residual-heat utilization hot-water heater which comprises an absorption heat pump, a heat exchanger and a condenser, wherein a waste steam outlet of the turbine is respectively connected with a waste steam outlet of the air cooling tower and a waste steam outlet of the condenser through steam exhaust cylinders, and a condensed water outlet of the condenser is connected with a water storage tank of the air cooling tower; a steam outlet of the absorption heat pump is connected with a steam extraction port of the turbine, a water inlet end of the absorption heat pump is connected with a water return end of a hot water pipe network, and the absorption heat pump is connected with the condenser in a closed loop to for a circulating water system; a steam inlet of the ...

Gas fuel oxygen-carried hydrogen-produced and carbon dioxide separation method and device

Dead-stream straight-condensation absorption type heat pump device

The invention relates to a dead-stream straight-condensation absorption type heat pump device comprising an evaporator, an absorber, a generator, a condenser and a solution heat exchanger. The evaporator is internally provided with an evaporation condensation heat exchanger; the heat exchanger is arranged in a regular triangle shape; both sides of the triangle are both provided with upper headers and lower headers; each lower header is provided with a condensation water outlet and a dead stream connection port; the dead stream connection ports of the two lower headers are communicated with each other; the condensation water outlets are connected; the dead stream exhausted from a turbine enters the upper header of a heat exchange tube beam on one side; the upper header distributes the dead stream to the heat exchange tube beam on the side; the flow direction of the condensation water in the heat exchanger tube on the side is the same as that of the dead stream; the dead stream on the side ...

Coordination control method for integral coal gasification combined circulation power station

The invention puts forward a coordinated control method for an integrated coal gasification combined cycle power plant, aiming at a characteristic that the time constant of each equipment of the controlled object in the integrated coal gasification combined cycle power plant has great difference. The method adopts a cascade stratified control system structure, and is provided with an upper-layered main controller, namely, a coordination controller, and a lower-layered sub controller, namely, comprising a gasification island sub controller and a power island sub controller, wherein, the main controller is used for the calculation of a main control command and then sends to the lower-layered sub controller for the control of corresponding equipments, the lower-layered sub controller is also in charge of the regulation of other main controlled variables in the system; the control method coordinates the running of each equipment of the power plant gasification island and the power island, and ...

Combined heat and power generation energy-saving device and method for supplying heat by waste heat

The invention relates to a combined heat and power generation energy-saving device and a method for supplying heat by waste heat, which belong to the technical field of energy sources. The device comprises a steam boiler, a steam turbine, an electricity generator, a steam condenser, a deaerator and a cooling tower, wherein the steam turbine is connected with the steam condenser through a steam exhaust cylinder, and the steam condenser is connected with the cooling tower through a pipeline for forming a large water path circulation. The invention is characterized in that the device also comprises a heat pump type heat network heater which is respectively connected with a heat supply pipe network, the steam turbine and the deaerator through pipelines, and the steam condenser, the heat pump type heat network heater and the cooling tower are connected through pipelines for forming a small water patch circulation. The device further comprises an automatic controller. The invention can reduce ...

Chemical chain combustion method and device through solid fuel

The invention discloses a chemical chain combustion method and a chemical chain combustion device through solid fuel. The method comprises the following steps that: an oxygen carrier Cu is oxidized by air in an air reactor to form CuO, and the CuO enters an oxygen release reactor and is decomposed to form Cu2O and release molecular oxygen O2; the Cu2O is accumulated in the oxygen release reactor and returns to the air reactor through a discharging pipe of the oxygen release reactor and an overflow tank, and the Cu2O is oxidized to form CuO again, and the CuO is recycled; and the molecular oxygen O2 released from the oxygen release reactor enters a fuel reactor and is subjected to a combustion reaction with fuel in the fuel reactor, gaseous products in the fuel reactors are CO2 and water vapor only, and after the water is condensed and separated, pure CO2 is obtained. The heat generated in the whole system is equal to the heat obtained by fuel combustion in the air, but CO2 is separated ...

Control method for restraining influence of coal mill start/stop to main vapour pressure of boiler

The invention relates to a control method for inhibiting the influence on main steam pressure of a boiler caused by that a coal pulverizer is started or stopped, and a rapid control layer of average rotating speed of a coal feeder is added on the basis of three-layer control mode of the original boiler fuel, so that the influence on the main steam pressure of the boiler caused by various operationof the operators is effectively inhibited when in the process that the coal pulverizer is started or stopped. A dynamic feed-forward technique based on the actual differential coefficient is appliedto the feed-forward design of a boiler main control system by the method, so that the command of automatically modifying the coal quantity in the boiler can be realized in the process that the coal pulverizer is started or stopped, and the excessive part of coal dust quantity which enters the boiler to be burnt is counteracted due to start grinding, warm grinding or stop grinding in the process ofpowder ...

Gasifying stove forecasting type PID control method

The invention relates to a control method of predicative proportion integration differentiation of a gasifier; aiming at the characteristics of nonlinearity, long time delay and strong coupling of the gasifier in the controlled process, the method uses the advantages of robustness and easy realization of the conventional PID control algorithm, combines the effectiveness of the predicative control method to the object with long time delay, uses the predicative control idea into the conventional PID control algorithm, uses a variable predictor to predict the input of the controlled object of the gasifier after L time, leads the reference input and the output of the variable predictor to subtract, takes the obtained results as the deviation of the entrance of a PID regulator, carries out a plurality of times of calculation, leads output of the obtained controller by two times of calculation to be constant basically, outputs the control function, realizes the advanced action of the regulator ...

Modeling and virtual simulating method for integrated coal gasification combined cycling air separating system

A method for modeling and simulating an air separation system of an integral gasification combined cycle power plant comprises the following steps: building up an accurate mathematical model of a rectifying tower according to mass balance, energy balance, gas-liquid phase balance, molecular normalization equation and physical property equations set of each tower tray; and carrying out simulation experiment for the air separation system, including the cold-state startup process of the rectifying tower and the operation under variable working conditions, so as to study the dynamic operating characteristics of the rectifying tower, as well as the dynamic, static and coupling relations among the input, the output and the disturbance variables of the system. The method is considerably helpful for further understanding the operating characteristics of the air separation system, setting a control strategy for the air separation system and optimizing the operation. Moreover, the method can bring ...

Advanced control method for thermal power unit boiler turbine coordination system

The invention provides an advanced control method for a coordination system of a boiler and a steam turbine of a thermal power unit, which applies advanced dynamic feedforward technology to the feedforward design of a main control system of the boiler so as to effectively accelerate governing speed of a boiler load command in a load varying process of the unit. In the load varying process of the unit, oscillation tendency of the main control system of the boiler can be inhibited through reducing integral action of a regulator. In the main control system of the steam turbine, a unit load command N0 is subjected to inertia LAG time-delay, and protection design is carried out on main steam pressure. The method ensures that the boiler and the steam turbine can operate under a more coordinated mode and ensures that the thermal power unit has faster ascending and descending speed of load and more stable variation of the main steam pressure, wherein the ascending and descending speed of the load ...

Gas fuel oxygen-carried hydrogen-produced and carbon dioxide separation method and device

This invention relates to a method for producing hydrogen by using combustible reducing gas as raw material, and using iron/ferrous oxide as oxygen-carrier, during the reaction in a fluidized bed reactor, with coproduct of high concentration carbon dioxide. This invented equipment comprises: a circulation fluidized bed, a moveable bed, a bubbling fluidized bed, a hydrogen separator unit and a carbon dioxide separator. A horn type bucket is used under the bottom of hydrogen separator and connecting the lower part of the bubbling fluidized bed; the bottom of the carbon dioxide separator is connected with horn type bucket; a contraction type bucket is used for connection middle lower part of the bubbling fluidized bed and the moveable bed; the upper part of moveable bed is connected with the middle part of the circulation fluidized bed; the lower ends of the circulation fluidized bed and moveable bed and bubbling fluidized bed are equipped with fluidized steam inlets A and B gas fuel inlet ...

Oxygen carrier gasifying combustion method for loading oxygen and device

The invention discloses an oxygen carrying gasification combustion method with an oxygen carrier as well as relevant apparatus; the method is characterized in that the oxygen carrier is arranged inside an air reactor fluidized bed; if fluidized air is fed, oxysome reacts with oxygen in the air before high-value metal oxide is heated to obtain; then, the oxide will be separated through a two-stageseparator; the high-temperature oxygen denuded air, which is separated, is exhausted out of the upper-end of the separator; the separated oxygen carrier goes through a returning dipleg to enter a mixing and gasification chamber; in a circulation fluidized bed in the air reactor, an oxygen carrying reaction happens between the oxygen carrier and oxygen in the air: The oxygen carrier from the reaction flows into the dipleg after being separated by the two-stage separator, so that the oxygen carrier and the fuel can together enter the gasification chamber below the fuel reactor fluidized bed; inthe ...

Fuel reactor device for chemical-looping combustion

The invention discloses a fuel reactor device for chemical-looping combustion. The device consists of a mixing and reaction chamber, an overflow groove, a transition section, a riser and a carbon dioxide separator, wherein the riser is connected with the mixing and reaction chamber through the transition section; the lower end of the riser is provided with a feed port, and the upper end of the riser is connected with the upper end of the carbon dioxide separator; the lower end of the carbon dioxide separator is connected with the mixing and reaction chamber through the overflow groove; the lower end of the mixing and reaction chamber is provided with a grid plate; the lower end of the mixing and reaction chamber is provided with a solid fuel inlet; a discharge port is formed on the outer side of the mixing and reaction chamber; and a loose air port is formed at the lower end of the overflow groove. Due to the large change of cross sections of the riser and the mixing and reaction chamber ...

Advanced control method for thermal power unit boiler turbine coordination system

The invention provides an advanced control method for a coordination system of a boiler and a steam turbine of a thermal power unit, which applies advanced dynamic feedforward technology to the feedforward design of a main control system of the boiler so as to effectively accelerate governing speed of a boiler load command in a load varying process of the unit. In the load varying process of the unit, oscillation tendency of the main control system of the boiler can be inhibited through reducing integral action of a regulator. In the main control system of the steam turbine, a unit load command N0 is subjected to inertia LAG time-delay, and protection design is carried out on main steam pressure. The method ensures that the boiler and the steam turbine can operate under a more coordinated mode and ensures that the thermal power unit has faster ascending and descending speed of load and more stable variation of the main steam pressure, wherein the ascending and descending speed of the load ...

Method and device based on coal gasification for preparing hydrogen and separating CO2

The invention discloses a method and a device based on coal gasification for preparing hydrogen and separating CO2. Coal and water vapor enter a gasification reaction chamber for gasification to obtain H2, CO and CO2. CO is converted to CO2 through a transformation reaction, and CO2 is absorbed by CaO to generate CaCO3. H2 and remnant CO2 enter a gasification bed rising pipe, and CaCO3 and remnant coke enter a calcium oxide regeneration reaction chamber. Pure oxide is introduced to the calcium oxide regeneration reaction chamber, the coke is burned with the oxide, CaCO3 is decomposed to CO2 and CaO, CO2 is separated with the CaO by a separator and is collected, and CaO enters the bottom of the gasification bed rising pipe to be raised by the H2 and the remnant CO2, and the CO2 is absorbed. Parts of the H2 and the CaO return to the bottom of the gasification bed rising pipe through a recirculating pipe. The other part of the H2 and the CaO are separated by the separator to obtain purified ...

Boiler fouling monitoring and soot blowing optimization methods based on on-line measurement of coal quality

The invention discloses boiler fouling monitoring and soot blowing optimization methods based on on-line measurement of coal quality. Responding to weak points and deficiencies of the existing soot blowing optimization method based on off-line measurement of the coal analysis data and based on boiler integral and partial energy and mass balance theory, a coal quality on-line analyzer analyzes the quality of the coal in the boiler on line, on-line monitoring, analysis and calculation are carried out on soot formation scorification and boiler furnace outlet gas temperature of the convection heating surface by the adverse flue gas process; in addition, real-time computation and analysis of the operation condition and pollution level of the heating surface of the boiler are carried out, thus eliminating adverse effect of quality change of coal in a pulverized coal fired boiler on soot blowing optimization guidance, providing correct soot blowing guidance and boiler performance optimization ...

Low-temperature heat energy recovering apparatus of heat and electricity co-generation and recovering method thereof

The invention relates to a low-temperature heat energy recovering apparatus of heat and electricity co-generation and a recovering method thereof. The apparatus comprises a steam boiler, a steam turbine, a generator, a condenser, a deaerator, a high-pressure heater, a cooling tower and a demineralized water pump. The steam turbine is connected with the condenser through an exhaust cylinder. The condenser is connected with the cooling tower through pipelines to form a water channel large circulation. The device is characterized by also comprising a water supplementing mixer and a heat pump type feed water heater, wherein the water supplementing mixture is respectively connected with the condenser and the demineralized water pump through pipelines, the heat pump type feed water heater is respectively connected with the water supplementing mixer and the deaerator through the pipelines. The condenser and the feed water heater are connected with the cooling tower through pipelines to form water ...

Control method for restraining influence of coal mill start/stop to main vapour pressure of boiler

The invention relates to a control method for inhibiting the influence on main steam pressure of a boiler caused by that a coal pulverizer is started or stopped, and a rapid control layer of average rotating speed of a coal feeder is added on the basis of three-layer control mode of the original boiler fuel, so that the influence on the main steam pressure of the boiler caused by various operation of the operators is effectively inhibited when in the process that the coal pulverizer is started or stopped. A dynamic feed-forward technique based on the actual differential coefficient is applied to the feed-forward design of a boiler main control system by the method, so that the command of automatically modifying the coal quantity in the boiler can be realized in the process that the coal pulverizer is started or stopped, and the excessive part of coal dust quantity which enters the boiler to be burnt is counteracted due to start grinding, warm grinding or stop grinding in the process of ...

Method and device for burning chemistry chains based on iron or iron oxide

The invention discloses a method and a device for burning chemistry chains based on iron or iron oxide, and the method comprises the following steps: placing iron or iron oxide in an air reactor fluidized bed; introducing fluidized air; obtaining Fe2O3 by reacting iron or iron oxide with oxygen in the introduced air; separating gas phase from solid phase by a separator; discharging the separated high-temperature oxygen-poor air from the top end of the separator; feeding the separated Fe2O3 in a fuel reactor fluidized bed via an overflow groove; feeding solid fuel in the fuel reactor fluidizedbed via a spiral feeder; generating synthesis gas by a gasification reaction in which the solid fuel reacts with the water vapour introduced from the bottom end of the fuel reactor; carrying out reduction reaction by reacting the synthesis gas or fuel with oxygen released by Fe2O3 to generate carbon dioxide; reducing Fe2O3 to FeO or Fe; returning to an air reactor fluidized bed via an overflow groove ...

Method and device for producing hydrogen and separating CO2 based on iron or iron oxide

The invention discloses a method and a device for producing hydrogen and separating CO2 based on iron or an iron oxide. The method comprises the following steps: putting the iron or the iron oxide in an air reactor fluidized bed, reacting the iron or the iron oxide with infused air to obtain Fe2O3, discharging the air separated by a separator from the upper end of the separator, causing the separated Fe2O3 to enter a fuel reactor fluidized bed, causing a solid fuel to enter the fuel reactor fluidized bed by a screw feeder, reacting the solid fuel with infused water vapor to generate a synthesis gas, subjecting the Fe2O3 and the synthesis gas or the fuel to a reduction reaction to generate carbon dioxide, reducing the Fe2O3 to FeO or Fe and overflowing to a hydrogen producing reactor, reacting the FeO or the Fe in the hydrogen producing reactor with the water vapor to generate the hydrogen, oxidizing the FeO or the Fe to be the Fe3O4, discharging the hydrogen gas separated by the separator ...

Thermoelectricity co-generation energy-saving device for supplying heat by using waste heat and energy-saving method thereof

The invention provides a thermoelectricity co-generation energy-saving device for supplying heat by using waste heat and an energy-saving method thereof. The device comprises a steam boiler, a turbine, an electric generator, a steam condenser, a deaerator and a cooling tower, wherein the turbine is connected with the steam condenser by an exhaust hood, and the steam condenser is connected with the cooling tower to form a big circulation of waterway; the device also comprises a waste heat utilization hot water heater comprising an absorbing type heat pump and a heat exchanger; a steam inlet of the absorbing type heat pump is connected with an extraction opening of the turbine, a water inlet of the absorbing type heat pump is connected with a water returning end of a hot water pipe network, and the steam condenser, absorbing type heat pump and cooling tower are connected to form a small circulation of waterway; a steam inlet of the heat exchanger is connected with the extraction opening of ...

Method and device based on coal gasification for preparing hydrogen and separating CO2

The invention discloses a method and a device based on coal gasification for preparing hydrogen and separating CO2. Coal and water vapor enter a gasification reaction chamber for gasification to obtain H2, CO and CO2. CO is converted to CO2 through a transformation reaction, and CO2 is absorbed by CaO to generate CaCO3. H2 and remnant CO2 enter a gasification bed rising pipe, and CaCO3 and remnant coke enter a calcium oxide regeneration reaction chamber. Pure oxide is introduced to the calcium oxide regeneration reaction chamber, the coke is burned with the oxide, CaCO3 is decomposed to CO2 and CaO, CO2 is separated with the CaO by a separator and is collected, and CaO enters the bottom of the gasification bed rising pipe to be raised by the H2 and the remnant CO2, and the CO2 is absorbed. Parts of the H2 and the CaO return to the bottom of the gasification bed rising pipe through a recirculating pipe. The other part of the H2 and the CaO are separated by the separator to obtain purified ...

Pure oxygen replaced coal gasifying method and its coal gasifying apparatus

The pure oxygen substituted coal gasifying process comprises setting metal sulfide into circular fluidizing bed and leading fluidizing air in from the bottom for reaction between metal sulfide and oxygen to obtain metal sulfate; making the metal sulfate enter to the bubbling fluidized bed via belled material returning leg, feeding fuel to the bubbling fluidized bed and making the fluidizing gas enter the bubbling fluidized bed from the bottom for reduction reaction between carbon and metal sulfate to produce CO. The coal gasifying apparatus consists of circular fluidizing bed and bubbling fluidized bed, the circular fluidizing bed has metal sulfide set inside it and fluidizing air inlet in the bottom, and the bubbling fluidized bed has fluidizing gas inlet in the lower end, poor-oxygen air separator connected to the upper part and gas separator connected to the upper part.

Combined heat and power generation energy saving device using afterheat to supply heat and energy saving method

The invention relates to a combined heat and power generation energy saving device using afterheat to supply heat and an energy saving method. The combined heat and power generation energy saving device comprises a steam boiler, a steam extraction condensed type steam turbine, an electric generator, a condenser, a deaerator and a cooling tower, wherein the steam extraction condensed type steam turbine is connected with the condenser by an exhaust steam cylinder, and the condenser is connected with the cooling tower to form large waterway circulation; the combined heat and power generation energy saving device also comprises a backpressure turbine, a compression heat pump and a heat exchanger, wherein a steam inlet of the backpressure turbine is connected with a steam extraction hole of the steam extraction condensed type steam turbine, an exhaust steam hole is connected with a steam inlet of the heat exchanger, the compression heat pump is drawn by the backpressure turbine and is connected ...