CN111894735A - A hydrogen gas turbine combined cycle polygeneration method without NOx emission - Google Patents

Abstract

The invention designs a hydrogen gas turbine combined cycle poly-generation method without NOx emission, which is composed of Brayton cycle and Rankine cycle. The present invention is mainly oriented towards _H2 or CxHyOz type nitrogen-free fuels. Using CO ₂ to replace N ₂ and cooperating with high-purity O ₂ produced by air separation, a circulating flue gas with CO ₂ and O ₂ as the main components is formed. Using a split gas turbine, the combustion produces high temperature flue gas, and the H ₂ O is separated by condensation and the flue gas is recycled to realize the continuous operation of the hydrogen gas turbine and avoid the thermal NOx problem caused by conventional air-assisted combustion. Due to the need of flue gas condensation, Rankine cycle and deep waste heat utilization of flue gas are used together. Key equipment or units include air separation oxygen production and storage, CO ₂ regeneration and storage, split gas turbines, waste heat boilers with supplemental combustion, Rankine cycle and equipment, condensing heat exchangers, flue gas recirculation and regulation, N ₂ Utilize units, etc.

Description

A hydrogen gas turbine combined cycle polygeneration method without NOx emission

technical field

The invention provides a gas turbine-based hydrogen energy power generation and multi-generation system without NOx emission, relates to a hydrogen split gas turbine and a matching flue gas circulation and regulation technology, and belongs to the technical field of comprehensive utilization of hydrogen fuel.

Background technique

Hydrogen energy is a clean secondary energy. With the large-scale production of hydrogen from fossil fuel reforming and the maturity of high-efficiency hydrogen production technology through hydrolysis, the hydrogen energy industry chain and its various links have developed vigorously. In terms of end use, the way of using hydrogen is hydrogen fuel cell technology. However, this technology has high hydrogen storage pressure, precious metal consumption, and low power density, so it is not very suitable for the field of power generation.

Hydrogen can also be used as fuel for internal combustion engines (CN107221959A) and rotary engines (CN 110509783 A), but the above two devices have low output power and are suitable for the field of freight vehicles or passenger vehicles, and are not suitable for power generation or multi-supply systems. Additionally, hydrogen-based internal combustion and rotary engines generate NOx emissions that partially offset the cleaning benefits of _H2 .

The gas turbine follows the Brayton cycle principle, with few moving parts, simple and compact structure, high combustion efficiency and high power density. Combined with the Rankine cycle to form a combined cycle system, it has the advantages of high efficiency, low cost, and can realize cogeneration, which is suitable for power generation and regional comprehensive energy fields. Hydrogen is an ideal alternative fuel for gas turbines due to its high calorific value, carbon-free and nitrogen-free fuel properties. However, conventional gas turbines use air as an oxidant, and thermal NOx pollutants still exist at high temperatures. Compared with the characteristics of no NOx emission of hydrogen fuel cell technology, this is the emission disadvantage of hydrogen gas turbines.

SUMMARY OF THE INVENTION

In order to realize the application of hydrogen energy in power generation or integrated energy system, and to avoid the problem that NOx is generated during the combustion of hydrogen in the gas turbine, the present invention provides a hydrogen gas turbine combined cycle polygeneration method without NOx emission, which adopts CO ₂ Hydrogen combined cycle power generation and polygeneration systems to replace _N2 and methods of operation thereof. At the same time, in order to overcome the high energy consumption of air separation and other processes, a perfect and effective energy recovery method has been implemented for the system to achieve overall high energy conversion efficiency by means of combined heat and power, or to improve overall economic benefits by means of combined heat, power and nitrogen. .

The technical scheme of the invention is as follows: a hydrogen gas turbine combined cycle polygeneration method without NOx emission, using _H2 or CxHyOz type gas-liquid nitrogen-free fuel, using high-purity _O2 prepared by air separation as an oxidant, and using _CO2 as an oxidant. In order to replace N ₂ as the circulating flue gas, it enters the split gas turbine for combustion, and generates power to generate high-temperature flue gas whose main components are CO ₂ , O ₂ and H ₂ O. The waste heat boiler (HRSG) recovers the high-temperature flue gas. and use the Rankine cycle for power generation or cogeneration, thereby improving the energy utilization efficiency of the system; the flue gas discharged from the waste heat boiler is deeply cooled, so that most of the water vapor is condensed, released and separated to obtain CO ₂ The cold flue gas with O ₂ as the main component is recycled and pressurized, and the cold flue gas is returned to the split gas turbine to form a closed cycle _; The expansion generator generates electricity, or utilizes the principle of expansion refrigeration to perform combined cooling and power generation, forming an electricity-heating/cooling- _N2 polygeneration system as a whole.

The purity of O ₂ separated from the air is above 95%, and the oxygen production under normal operating conditions is the theoretical combustion oxygen consumption.

The initial combustion temperature of the split gas turbine is 1200-1700 ℃, the oxygen excess coefficient is 2.0-3.6, the O ₂ concentration in the flue gas after combustion is 9.9-22.7 mol%, the CO ₂ concentration is 77.3-90.1 mol%, and the exhaust gas temperature is lower than 900 ℃.

The high-temperature flue gas is recycled, the main component is CO ₂ , and the concentration range is 62.3-87.4 mol%. The high-temperature flue gas is circulated by micro-positive pressure, and the pressure is not less than 500Pa.g.

When condensing, the pressure is not lower than 1kPa.g, and the temperature is not higher than 40℃; at the same time, it is equipped with a dryer to accurately control the moisture content of the flue gas in fault conditions or specific operations, and ensure that the dew point of the circulating flue gas is at least higher than the lowest temperature in the operating state 5°C lower.

The multi-source CO ₂ replenishment and storage unit is used to quickly replenish the CO ₂ in the startup or failure stage by operating in two modes: start-up replenishment and operation replenishment. There are four sources of CO ₂ : high-purity CO ₂ provided by the outside world, local air Capture and extract CO ₂ ; CO ₂ obtained from flue gas separation; CO ₂ generated by CxHyOz gas-liquid nitrogen-free fuel combustion.

The device applied to the above method includes a hydrogen fuel conditioning unit, a split gas turbine, an air separation and storage unit, a waste heat boiler, a Rankine cycle unit, a condensing heat exchanger, a flue gas circulation and regulation unit, and a _CO2 regeneration and storage unit and nitrogen utilization unit; the hydrogen fuel conditioning unit is connected to the combustion chamber of the split gas turbine; according to the flue gas direction, the split gas turbine and the waste heat boiler, the condensing heat exchanger, the flue gas circulation and regulation unit, and the CO ₂ regeneration and storage unit form a unit Closed circuit; the combustion chamber of the split gas turbine is connected to the air separation and storage unit; the waste heat boiler is connected to the _Rankine cycle unit, and the waste heat boiler is provided with a fuel inlet; The second compressor B and the flue gas storage and regulator PFV are connected in sequence according to the flue gas direction. The second compressor is directly connected to the CO ₂ regeneration and storage unit, and the other is connected to the combustion chamber of the split gas turbine. The storage and voltage stabilizer is connected to the combustion chamber of the split gas turbine; the _CO2 regeneration and storage unit includes a flue gas _CO2 separation device CS, a high-pressure _CO2 storage and voltage stabilizer CPV and an air extraction _CO2 device CSA, mainly for circulating smoke Gas supplement and adjust CO ₂ concentration, the supplement point is set before or after the second compressor; the flue gas CO ₂ separation device is connected with the combustion chamber of the split gas turbine, and also is provided with an outlet for impurity gas, a high-pressure CO ₂ storage and a voltage stabilizer The CPV is provided with a carbon dioxide inlet, and is also connected to the air separation and storage unit; the air separation and storage unit includes a first compressor A, an air separation oxygen production device AS, and an oxygen storage container OPV; the first compressor and the air separation oxygen production device AS Connection, the air separation oxygen generator AS is connected with the oxygen storage container OPV, and the air separation oxygen generator AS is also connected with the nitrogen utilization unit to provide high-pressure air for the nitrogen utilization unit; the air separation oxygen generator AS and the oxygen storage container OPV are both connected with the The combustor of the integrated gas turbine is connected; the N ₂ utilization unit includes the N ₂ temperature regulator TC _N2 , the expansion generator G3 and the cold energy recovery device CE, and the nitrogen temperature regulator, the expansion generator and the cold energy recovery device are connected in the direction of nitrogen.

The first and second compressors are driven by both electric drive and mechanical drive; when the gas turbine is started, it is driven by external electricity, and when the gas turbine is running, it is directly mechanically driven by the gas turbine bearing through the gearbox; the second compressor (B ) is not less than 18.1.

The split gas turbine includes a combustion chamber, a hydrogen turbine and a generator, the combustion chamber and the hydrogen turbine are connected according to the direction of flue gas, and the generator is arranged at the end of the combustion chamber.

beneficial effect

1. The system of the present invention can meet the high-efficiency utilization of hydrogen energy in the field of high-power power generation, and realizes the combustion and utilization of _hydrogen based on split gas turbines without NOx emissions, using H as fuel and high _- purity O obtained after air separation as The oxidant uses CO ₂ as the main component of the gas instead of N ₂ , generates power through the gas turbine, and generates flue gas with the main components of CO ₂ , O ₂ and H ₂ O, completely avoiding the problem of NOx generation.

2. High energy conversion efficiency or flexible utilization of by-products can be achieved through the polygeneration design. By setting up a waste heat boiler (HRSG), combined with the Rankine cycle, the power generation efficiency is improved. The boiler exhaust flue gas is then subjected to heat exchange and condensation. On the one hand, CO ₂ and O ₂ in the flue gas are recovered, and on the other hand, the latent heat of the phase change of water vapor is utilized for deep utilization of the residual heat of the flue gas. At the same time, the high-purity N ₂ produced by air separation is used to form an electric-heat/cold-N ₂ polygeneration system.

3. The condensed flue gas of the present invention contains a large amount of water vapor, and a condensing heat exchanger is arranged to discharge excess water from the condenser to the circulation system, and at the same time, the deep recovery of the residual heat of the flue gas is realized. The pressure of the condenser is not lower than 1kPa.g, and the temperature is not higher than 40℃. At the same time, it is equipped with a dryer to precisely control and ensure the moisture requirements of circulating flue gas for fault conditions or specific operations.

4. The present invention is equipped with a split gas turbine, that is, only the combustion chamber, turbine and generator of the traditional integrated gas turbine are retained. By setting up oxygen, flue gas and CO ₂ storage and regulator containers, it can meet the variable load requirements such as operating condition adjustment, circulating flue gas pressure maintenance and adjustment.

5. In order to solve the possible trace leakage of flue gas such as starting inflation, dynamic and static gaps, interface valves, etc., it is equipped with a multi-source CO ₂ supplement and storage unit, which is divided into two modes: start supplement and operation supplement. There are three sources of CO ₂ supplementation: high-purity CO ₂ provided by the outside world, CO ₂ captured by in-situ air; CxHyOz type N-free fuel combustion supplement. The brief operation and cooperation mode is as follows: in-situ air capture is only for trace operating leakage; the high-purity CO ₂ provided by the outside is mainly for the first start after the flue air duct is fully contacted with the atmosphere (such as installation, overhaul), and the auxiliary is used as equipment. The gas charging protection and operation leakage of CxHyOz nitrogen-free fuel are mainly for fast start-up, which is used to quickly establish a flue gas system that meets the work of the gas turbine and assist in compensating for operation leakage.

6. The present invention is clean and efficient, but due to the complexity of the system and the interlocking limitation of functions, the output power adjustment rate of the present invention is inferior to that of conventional air-type gas turbines, so it is not suitable for peak shaving power generation.

Description of drawings

Fig. 1 is a system diagram of a hydrogen gas turbine combined cycle process without NOx emission of the present invention.

In the figure ①-H ₂ fuel conditioning unit, ②- air separation and storage unit, ③- split gas turbine, ④- waste heat boiler and CO ₂ rapid replenishment unit, ⑤- Rankine cycle unit, ⑥- condensing heat exchanger, ⑦ - Flue gas circulation and regulation unit, ⑧-CO ₂ regeneration and storage unit, ⑨-N ₂ utilization unit. A-First Compressor, AS-Air Separation Oxygen Generator, OPV-Oxygen Storage and Regulator, G1-Gas Turbine Generator, G2-Rankine Cycle Generator, G3-Nitrogen Expansion Generator, CSA-Air CO ₂ Extraction unit, CPV - high pressure CO ₂ storage and regulator, CS - flue gas CO ₂ separation unit, FPV - high pressure flue gas storage and regulator, B - second compressor, Q _rl - heat recovery from waste heat boiler, Combustion chamber CC, hydrogen turbine TB, vent damper _VE , dryer DR, second compressor B.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and specific embodiments. This description is only a slow or unfavorable start-up scheme among the multiple start-stop schemes of the present invention, and other start-up methods are not listed one by one.

System principle and equipment description

A hydrogen gas turbine combined cycle polygeneration method without NOx emission, the device and its main functions are divided as follows:

①-Hydrogen fuel adjustment unit: According to the requirements of the gas turbine, adjust the parameters such as the pressure, flow rate and temperature of the incoming hydrogen.

②- Air separation and storage unit: It consists of the first compressor A, the oxygen separator AS, the oxygen storage and pressure regulator OPV and its key control valve, and also includes the secondary pressurization equipment that may be required. This unit produces high-purity oxygen with an O ₂ concentration of 95%, and provides the required oxygen within the corresponding response time under various operating conditions such as startup, operation, and CO ₂ supplementation of the system. The air is pressurized by the first compressor and enters the air separation oxygen generator AS to separate high-purity and high-pressure oxygen, and the high-purity oxygen enters the combustion chamber of the split gas turbine as an oxidant. When the OPV gas storage capacity is low, the AS workload is increased, and the excess _O2 is supplied to the OPV storage.

③-Split gas turbine: This gas turbine is mainly composed of combustion chamber CC, hydrogen turbine TB, gas turbine generator G1, transmission shaft and other components. The combustion chamber and the hydrogen turbine are connected in series in the direction of intake air, and the transmission shaft is conducted to the generator to generate electricity, and the gas turbine generator G1 is at the end of the combustion chamber. Its combustor and turbine are designed for hydrogen combustion ignition and flame characteristics. The initial combustion temperature is 1200～1700℃, and the pressure and heat loss of the combustion chamber are not more than 2%. The oxygen excess coefficient is 2.0 to 3.6. After combustion, the O ₂ concentration in the flue gas is 9.9-22.7 mol%, the CO ₂ concentration is 77.3-90.1 mol%, and the exhaust gas temperature is lower than 900 ℃.

④- Waste heat boiler and CO ₂ rapid replenishment unit: This module is mainly a waste heat boiler (HRSG) with pure oxygen supplementary combustion function. It has two functions: First, in normal operation, the heat energy of the high-temperature exhaust gas of the hydrogen gas turbine is exchanged to the ⑤ Rankine cycle to provide high-temperature and high-pressure steam for the cycle. Generally, the exhaust gas temperature of the waste heat boiler is about 90°C, and the heat recovered by the waste heat boiler is Q _rl . 2. In the start-up stage or in the event of an emergency, the CxHyOz-type nitrogen-free fuel is burned with pure oxygen to quickly generate CO ₂ and H ₂ O in large quantities, and most of the H ₂ O is separated by cooling and condensation, and the CO ₂ concentration in the flue can be achieved with the flue gas circulation function. And the rapid accumulation of the total amount, so as to meet the demand for rapid replenishment of _CO2 .

⑤-Rankine cycle unit: including a complete set of Rankine cycle devices. According to the different demand for power generation or cogeneration, the steam turbine in the Rankine cycle can be of pure condensing type, back pressure type, extraction condensation type and extraction condensation type. formula and other types.

⑥-Condensing heat exchanger: Condenses the flue gas of the gas turbine, and discharges the water vapor in the flue gas in the form of condensed water, so as to realize the quality conservation of the system. The temperature of the flue gas after condensation does not exceed 40°C, preferably 35°C and below.

⑦- Flue gas circulation and regulation unit: The flue gas circulation of the present invention adopts a micro positive pressure mode to prevent air from leaking into the circulating flue gas and mixing N ₂ . This unit consists of venting damper _VE , dryer DR, second compressor B, high-pressure flue gas storage and regulator FPV and key control valve.

A venting damper V _E is set in front of the dryer. The venting damper has two main functions. On the one hand, after installation or maintenance, the air in the circulation is extracted by a vacuum fan through this damper; Gas, or release part of unqualified flue gas during operation, and then adjust the composition of circulating flue gas. When the circulating flue gas leaks due to a slight fault or non-condensable impurity gas accumulates, part of the unqualified flue gas is released. The dryer is used to accurately control the water vapor content in the flue gas, which varies with the design back pressure of the gas turbine.

The cold flue gas separated by the condensing heat exchanger ⑥ first passes through the dryer for necessary drying and then enters the second compressor, and is pressurized to obtain high-pressure flue gas. During normal operation, the high-pressure flue gas is sent to the split gas turbine ③. Under the premise that the load allows, part of the high-pressure flue gas is sent to the flue gas storage and voltage stabilizer FPV for storage and backup. When the load increases rapidly or restarts after shutdown, the emergency part of the flue gas is output from the FPV to rapidly increase the circulation volume of flue gas. Similarly, it is also possible to supply part of the flue gas to the flue gas CO ₂ separation device CS, and separate high-purity CO ₂ from the flue gas with higher CO ₂ concentration.

Taken together, this unit realizes the functions of flue gas recirculation, flue gas storage, and flue gas stabilization.

In addition, the driving of the first compressor A and the second compressor B includes both electric driving and mechanical shaft driving. When the gas turbine is started, it is driven by external electricity. When the gas turbine is running, it can be mechanically driven directly through the gearbox using the gas turbine bearings.

⑧-CO ₂ regeneration and storage unit: composed of flue gas CO ₂ separation device CS, air CO ₂ extraction device CSA, high pressure CO ₂ storage and regulator CPV and key control valve, this unit realizes CO ₂ separation, storage and compensation and other functions, and then cooperate with the flue gas circulation and control unit to control the quality and composition of the circulating flue gas. The function of this unit is to supplement and regulate the CO ₂ concentration in the circulating flue gas. First, there are three ways to supplement CO ₂ : (a) high-purity CO ₂ is provided from the outside world, (b) CO ₂ is extracted from the air, and the above applies to the CO ₂ supplement required for trace leakage during normal operation. (c) The flue gas provided from the second compressor B enters the flue gas CO ₂ separation device CS, and the CO ₂ is separated out and stored in the FPV, and the remaining impurity gas is discharged to the atmospheric environment. It is suitable for the CO ₂ required for the sudden increase of the flue gas circulation volume under the conditions of startup, fault or sudden load. This mode also works in tandem with the _CO2 rapid replenishment function in unit ④ for faster response to load.

Secondly, the replenishment position of _CO2 can be either after the second compressor or before it. When the CPV pressure is sufficient and the supplementary amount is small, CO ₂ can be injected directly from the flue after the second compressor; when the CPV pressure is low or the supplementary amount is large, it needs to be supplemented from the flue gas pipeline before the second compressor CO ₂ .

⑨-N ₂ utilization unit: including N ₂ temperature regulator TC _N2 , expansion generator G3 and cold energy recovery device CE. There are two main ways to utilize the high-pressure and high-purity N ₂ by-product of air separation: (a) After cooling, it is loaded into a high-pressure steel cylinder or pipeline, and used as a nitrogen raw material for material utilization. (b) According to the nearby energy demand, use the expansion screw machine to generate electricity, and at the same time cooperate with the intake pressure, and use the principle of expansion refrigeration to obtain two useful energies of cold and electricity.

The functions listed above are necessary or key functions to realize the present invention, including but not listed common equipment and functions, such as mature water vapor Rankine cycle equipment and technology, secondary booster machinery, and flue gas extractor.

Operation mode description:

A NOx-free hydrogen power generation and multi-generation process based on power machinery mainly includes the following operation controls.

Start-up stage: the combustion process involved in the present invention is essentially a gas combustion system composed of H ₂ , O ₂ and CO ₂ . Therefore, the key to the start-up phase is to flush the mixture of O ₂ and CO ₂ throughout the entire air duct of the flue gas circulation from the flue gas turbine combustor. When starting for the first time, first use the suction machine to form a negative pressure through the 7-smoke venting damper.

_O2 filling: Method 1: _O2 is produced by air separation oxygen generator AS. Method 2: When a quick start is required, the _O2 storage and the oxygen stored in the voltage stabilizer OPV can also be used for quick flushing.

CO ₂ filling: Method 1: Provide excess O ₂ to the waste heat boiler from the air separation and storage unit, inject CxHyOz type gas or liquid fuel, start the flue gas circulation, and gradually form O ₂ +CO through the accumulation of combustion and flue gas circulation Type ₂ flue gas. Method 2: Use the CO ₂ injected from the outside to store and store CO ₂ in the regulator CPV. At this time, with the air separation and storage unit, the rapid ignition and operation of the gas turbine can be achieved.

Stable operation stage: After the flue gas meets the requirements of the circulating flue gas, it runs according to the set gas ratio, and the excess air coefficient is 2.0 to 3.6. The volume concentration of oxygen in the dry flue gas is about 9.9% to 22.7%. The amount of pure oxygen produced by air separation = the designed oxygen amount for combustion - the oxygen amount in the circulating flue gas, which is the theoretical combustion oxygen amount. Since a large amount of oxygen is carried in the circulating flue gas, in the stable operation stage, the oxygen amount required for real-time supplementation in the present invention is only the theoretical combustion oxygen consumption. Therefore, the energy consumption of air separation is low.

Flue gas adjustment stage: After running for a period of time, the system may cause the circulating flue gas volume and its composition to gradually change due to factors such as shaft seal leakage and accumulation of impurity gas. The adjustment measures are: release part of the flue gas through the flue gas release damper, and adjust the flue gas composition through the CO ₂ and O ₂ supplementary functions.

According to the external demand, the present invention can configure different types of steam turbines for the Rankine cycle unit, and can generate electricity or sell and utilize N ₂ . The above different combinations can realize at least the following three operating models:

Power generation priority mode: The power equipment is configured as follows: split gas turbine generator, pure condensing steam turbine and its generator, screw generator. In this mode, _N2 is used for power generation after air separation, which can make the power generation efficiency of the whole plant under typical working conditions. An increase of about 1.1 percentage points. The effective product of this mode is electricity, low temperature heat.

Cogeneration mode: The power equipment is configured as follows: split gas turbine generator, extraction condensing or back pressure steam turbine, screw generator. The effective products of this mode are electricity, medium and high temperature heat, and low temperature heat.

Electric heating and nitrogen cogeneration mode: The power equipment is configured as follows: split gas turbine generator, pure condensing, extraction condensing or back pressure steam turbine and its generator, nitrogen is filled into steel cylinders, or transported through pipelines. The efficient products of this mode are electricity, low or medium high temperature heat, high purity _N2 .

Example

start up:

Open the flue gas release damper, start the air separation and oxygen production unit ② to prepare pure oxygen, the purity of O ₂ is 97%, and supply excess pure oxygen to the waste heat boiler ④. At the same time, the CO ₂ rapid replenishment function is turned on, and CxHyOz fuel, such as methane, is injected into the waste heat boiler, and the combustion generates CO ₂ . When the flue gas pressure in the circulation space gradually rises and the CO ₂ concentration exceeds 20vol%, open the flue gas CO ₂ separation device (CS), increase the fuel input in the waste heat boiler ④, and quickly replenish CO ₂ . On the one hand, the flue gas flow in the circulation space is increased, and on the other hand, CO ₂ is separated and stored to prepare for the adjustment of flue gas components. When the CO ₂ concentration of the flue gas is close to the typical design value (85vol%), the compressor pressure is increased, and the flue gas is gradually injected into the high-pressure flue gas storage and regulator FPV, which is used for the rapid adjustment of flue gas flow and composition.

normal operation:

When the flue gas composition in the circulation space is qualified, the _{CxHyOz fuel} is _stopped , and the _CO2 rapid replenishment function is turned off. Open the _H2 valve and send it into the combustion chamber of the split gas turbine ③ through the fuel conditioning module. At the same time, the air separation and storage unit increases the load, and supplies O ₂ with a purity of 97% to the combustion chamber. The operating pressure ratio of the second compressor was 38.1. With the qualified flue gas in the circulation space, a combustion substance with a H ₂ /O ₂ /CO ₂ molar ratio of 1:1.4:3.3 is formed, the oxygen excess coefficient is 2.8, and the combustion-supporting gas O ₂ concentration is 29.8mol%. Ignition in the combustion chamber, the temperature of the combustion chamber is _1336.9 ℃, and the high temperature and high pressure flue gas is generated to push the hydrogen turbine to do work. The low-pressure exhaust gas of the split gas turbine enters the waste heat boiler, and the heat is transferred to the Rankine cycle unit. In this example, the pure condensing steam turbine is configured for power generation. After being cooled by the waste heat boiler, the flue gas temperature is about 95°C. After the flue gas enters the condensing heat exchanger ⑥, the heat exchange is further reduced to 35 ℃, and the condensation and water removal are realized. After condensation, the water vapor concentration in the flue gas is 0.09%. After condensation, the flue gas enters the dryer and goes through the molecular sieve drying process to further control or remove water vapor. The dried low-pressure flue gas is pressurized by the second compressor and then enters the FPV or directly returns to the combustion chamber to complete the cycle.

The air separation by-product _N2 exhaust parameters are 25°C, 0.53MPa. The exhaust gas temperature is -31°C after expansion by the expansion generator, and then the N ₂ is recovered, and the heat is exchanged to 5°C and then discharged to the atmospheric environment.

Smoke control:

For the trace leakage loss that occurs during normal operation, the CO ₂ regeneration and storage unit is operated, and CO ₂ is extracted from the air by chemical solvent absorption method or resin adsorption method to supplement the circulation trace loss. When the equipment fails and leaks, on the one hand, properly reduce the load, and at the same time open the valves of the flue gas storage and regulator FPV to supplement the flue gas. When the circulating flue gas exceeds the limit due to the accumulation of non-condensable impurities, the flue gas release damper, flue gas storage and regulator FPV valve are simultaneously opened to adjust the flue gas flow and composition. If the adjustment capacity is not enough, open the CO ₂ storage and regulator CPV valve, increase the oxygen production capacity of the air separation, and accelerate the replenishment. If the required amount of flue gas release increases, the supplementary combustion function of the waste heat boiler is turned on, and CO ₂ is quickly supplemented by burning CxHyOz fuel.

Downtime:

First, the split gas turbine operation, air separation and storage unit, Rankine cycle and other units. The second compressor continues to work, the flue gas circulation and regulation unit and the _CO2 regeneration and storage unit are turned on, and the _CO2 component in the circulation volume is recovered. When the _CO2 concentration is lower than 20vol% or the circulation space pressure is lower than the external atmospheric pressure, the second compressor is stopped. Operation of the secondary compressor and other units.

Typical performance indicators:

Taking the maximum power generation mode as an example, the key performance indicators of this example are as follows: the power generation thermal efficiencies of the split gas turbine, pure condensing Rankine cycle, and _N2 screw expansion generator are 32.51%, 19.24%, and 1.58%, respectively. Combined cycle power generation The efficiency is 53.33% (low calorific value). The above parameters are calculated based on the conventional low calorific value. In addition, the efficiency can be increased by 0.98% through cold energy recovery. When taking into account the heat recovered by the condensation of flue gas, the high calorific value should be used for calculation, because the high temperature calorific value of _H2 is 18% larger than the low calorific value, which will cause a decrease in thermal efficiency. Under this condition, the thermal efficiency of flue gas condensation recovery in this case is 19.21, and the comprehensive thermal efficiency is 65.28% (high calorific value).

Claims (9)

1. a hydrogen gas turbine combined cycle polygeneration method without NOx discharge is characterized in that, with H ₂ or CxHyOz type gas-liquid nitrogen-free fuel, the high-purity O that is produced by air separation is oxidant, and with _{CO 2 is} Instead of N ₂ as the circulating flue gas, it enters the split gas turbine for combustion to generate power and generate high-temperature flue gas whose main components are CO ₂ , O ₂ and H ₂ O. The heat in the high-temperature flue gas is recovered through the waste heat boiler (HRSG). , and use the Rankine cycle for power generation or cogeneration, thereby improving the energy utilization efficiency of the system; the flue gas discharged from the waste heat boiler is deeply cooled, so that most of the water vapor is condensed, released and separated to obtain CO ₂ and The cold flue gas with O ₂ as the main component is recycled and pressurized, and the cold flue gas returns to the split gas turbine to form a closed cycle; in addition, the high-purity and high-pressure N ₂ generated by air separation is used as nitrogen raw material, or through expansion The generator generates electricity, or uses the principle of expansion refrigeration to carry out co-generation of cooling and power, forming an electricity-heating/cooling-N ₂ polygeneration system as a whole. 2. The hydrogen gas turbine combined cycle polygeneration method without NOx emission according to claim ₁ , characterized in that, the purity of O separated from the air is above 95%, and the oxygen production under normal operation state is the theoretical combustion consumption amount of oxygen. 3. The NOx-free hydrogen gas turbine combined cycle polygeneration method according to claim 1, wherein the combustion initial temperature of the split gas turbine is 1200-1700 °C, the oxygen excess coefficient is 2.0-3.6, and the flue gas after combustion The concentration of O ₂ is 9.9-22.7 mol%, the concentration of CO ₂ is 77.3-90.1 mol%, and the exhaust gas temperature is lower than 900 ℃. 4. The hydrogen gas turbine combined cycle polygeneration method without NOx emission according to claim 1, characterized in that the high temperature flue gas is used cyclically, the main component is CO ₂ , the concentration range is 62.3-87.4 mol%, and the high temperature flue gas is circulated The micro-positive pressure method is adopted, and the pressure is not less than 500Pa.g. 5. the NOx-free hydrogen gas turbine combined cycle polygeneration method according to claim 1, characterized in that, during condensation, the pressure is not lower than 1kPa.g, and the temperature is not higher than 40°C; The moisture content of flue gas in fault conditions or specific operations is precisely controlled, and the dew point of the circulating flue gas is guaranteed to be at least 5°C lower than the lowest temperature in the operating state. 6. The NOx-free hydrogen gas turbine combined cycle poly-generation method according to any one of claims 1 to 5, wherein a multi-source CO ₂ supplement and storage unit is used, and the operation is performed in two modes: start-up supplement and operation supplement Quickly replenish CO ₂ during startup or failure. There are four sources of CO ₂ : high-purity CO ₂ provided by the outside world, CO ₂ extracted by in-situ air capture; CO ₂ obtained from flue gas separation; CxHyOz type gas-liquid free gas CO ₂ from the combustion of nitrogen fuels. 7. The device applied in any one of claims 1 to 5, characterized in that it comprises a hydrogen fuel conditioning unit, a split gas turbine, an air separation and storage unit, a waste heat boiler, a Rankine cycle unit, a condensing heat exchanger, Flue gas circulation and regulation unit, CO ₂ regeneration and storage unit and nitrogen utilization unit; hydrogen fuel regulation unit is connected with the combustion chamber of the split gas turbine; The circulation and regulation unit, CO ₂ regeneration and storage unit form a closed loop; the combustion chamber of the split gas turbine is connected with the air separation and storage unit; the waste heat boiler is connected with the Rankine cycle unit, and the waste heat boiler is provided with a fuel inlet; the flue gas circulation and The control unit includes a venting damper _VE , a dryer DR, a second compressor B, and a flue gas storage and voltage stabilizer PFV, which are connected in sequence according to the flue gas direction. The second compressor is directly connected to the CO ₂ regeneration and storage unit all the way. The other way is connected to the combustion chamber of the split gas turbine, and the flue gas storage and regulator is connected to the combustion chamber of the split gas turbine; the CO ₂ regeneration and storage unit includes the flue gas CO ₂ separation device CS, high-pressure CO ₂ storage and regulator CPV and air extraction _CO2 device CSA mainly supplement and adjust _CO2 concentration for circulating flue gas, the supplementary point is set before or after the second compressor; the flue gas _CO2 separation device is connected with the combustion chamber of the split gas turbine, and is also set There are impurity gas outlet, high pressure CO ₂ storage and voltage stabilizer CPV set carbon dioxide inlet, and also connected with air separation and storage unit; air separation and storage unit includes first compressor A, air separation oxygen generator AS, oxygen storage container OPV; the first compressor is connected to the air separation oxygen generator AS, the air separation oxygen generator AS is connected to the oxygen storage container OPV, and the air separation oxygen generator AS is also connected to the nitrogen utilization unit to provide high-pressure air for the nitrogen utilization unit; The separate oxygen generator AS and the oxygen storage vessel OPV are connected to the combustion chamber of the split gas turbine; the _N2 utilization unit includes the _N2 temperature regulator TC _N2 , the expansion generator G3 and the cold energy recovery device CE, the nitrogen temperature regulator, the expansion The generator and the cold energy recovery unit are connected in the direction of nitrogen. 8 . The device according to claim 6 , wherein the first and second compressors are driven in two ways: electric drive and mechanical drive; when the gas turbine is started, it is driven by external electricity, and when the gas turbine is running, it is driven by an external electric power. 9 . The gas turbine bearing is directly mechanically driven through the gearbox; the pressure ratio of the second compressor (B) is not lower than 18.1. 9. The device according to claim 6, wherein the split gas turbine comprises a combustion chamber, a hydrogen turbine and a generator, the combustion chamber and the hydrogen turbine are connected according to the direction of flue gas, and the generator is arranged in the combustion chamber end.

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