Biomass energy gasification gas-steam combined cycle power generation system and process

Abstract

The invention relates to the technical field of biomass energy power generation, in particular to a biomass energy gasification gas-steam combined cycle power generation system and process. The system comprises a gasification furnace, a fuel gas outlet of the gasification furnace is connected with a first waste heat boiler, a fuel gas outlet of the first waste heat boiler is connected with an internal combustion engine generator set, and a high-temperature flue gas outlet of the internal combustion engine generator set is connected with a second waste heat boiler. And steam outlets of the first waste heat boiler and the second waste heat boiler are connected with a steam turbine generator set. The flexibility of the system is improved through combined operation of the steam turbine generator set and the internal combustion engine generator set; the fuel gas cooled by the first waste heat boiler and produced steam are fully utilized, the efficiency of converting biomass energy into electric energy is greatly improved, energy waste is reduced, and the comprehensive energy utilization rate of the whole system is remarkably increased.

Description

Technical Field

[0001] The present invention relates to the technical field of biomass energy power generation, and in particular to a biomass energy gasification gas-steam combined cycle power generation system and process. Background Art

[0002] As the demand for renewable energy continues to increase, biomass energy has received widespread attention as a sustainable energy source. Traditional biomass power generation technology has problems such as low efficiency and poor gas quality. In the biomass gasification process, the choice of gasifier has a key impact on the gasification effect and subsequent power generation efficiency. The gasifier used in traditional biomass gasification power generation technology generally contains air. The large amount of N2 brought in by the air makes the synthesis gas contain a large amount of N2 and nitrogen oxides, diluting the effective components H2, CO, and CH4, reducing the biomass gasification efficiency, and thus reducing the power generation efficiency of the system. At present, the use of air as a gasifier will result in a high nitrogen content in the gas and reduce the calorific value of the gas; while the use of oxygen as a gasifier has the potential to improve the calorific value and quality of the gas, but the existing related systems still have deficiencies in design and collaborative work, and need to be further optimized to achieve efficient power generation.

[0003] In order to improve the efficiency of biomass energy power generation and increase the calorific value and quality of fuel gas, the present invention provides a biomass energy gasification fuel gas steam combined cycle power generation system and process. Summary of the invention

[0004] The first object of the present invention is to provide a biomass energy gasification gas-steam combined cycle power generation system, which can improve the biomass energy power generation efficiency and improve the calorific value and quality of the gas.

[0005] The present invention provides a biomass gasification gas-steam combined cycle power generation system, comprising a gasifier, wherein the gas outlet of the gasifier is connected to a first waste heat boiler, the gas outlet of the first waste heat boiler is connected to an internal combustion engine generator set, the high-temperature flue gas outlet of the internal combustion engine generator set is connected to a second waste heat boiler, and the steam outlets of the first waste heat boiler and the second waste heat boiler are both connected to a steam turbine generator set.

[0006] Preferably, the jacket water outlet of the internal combustion engine generator set is connected to the inlet of the heat source section of the waste heat recovery device, and the outlet of the heat source section of the waste heat recovery device is connected to the jacket water inlet of the internal combustion engine generator set; the inlet of the heating section of the waste heat recovery device is connected to the condensed water of the power plant.

[0007] Preferably, a cyclone separator is provided between the gasifier and the first waste heat boiler.

[0008] Preferably, a cyclone dust collector is provided between the gasifier and the cyclone separator.

[0009] Preferably, the gasifier is a 10 t / h biomass gasifier.

[0010] The present invention also provides a power generation process of a biomass gasification gas-steam combined cycle power generation system, comprising the following steps:

[0011] S1. Oxygen is input into the gasifier as a gasifying agent, and the biomass raw material undergoes a chemical reaction in the gasifier to produce high-temperature combustion gas; when oxygen is used as a gasifying agent, the biomass can react more efficiently in the gasifier, and the gasification reaction can be carried out at a more appropriate oxygen concentration, so that the pyrolysis, oxidation and reduction reactions of the biomass can be carried out more fully, thereby improving the gasification efficiency and increasing the output of combustion gas.

[0012] S2. The high-temperature gas is purified and input into the first waste heat boiler, the sub-high-temperature gas after heat release and cooling is input into the internal combustion engine generator set, and the medium-temperature and medium-pressure steam produced by the first waste heat boiler is input into the steam turbine generator set to generate electricity;

[0013] S3. The high-temperature flue gas generated by the internal combustion engine generator set is input into the second waste heat boiler, and the medium-temperature and medium-pressure steam produced by the second waste heat boiler is input into the steam turbine generator set to generate electricity.

[0014] Preferably, after the high-temperature cylinder jacket water of the internal combustion engine generator set is output, it enters the inlet of the heat source section of the waste heat recovery device, is cooled by the heat source section of the waste heat recovery device, and then returns to the periphery of the cylinder jacket of the internal combustion engine generator set to complete the cycle.

[0015] Preferably, the temperature of the high-temperature gas generated by the gasifier in step S1 is 750-850°C, and the calorific value is 10000-15000 kJ / Nm 3 .

[0016] Preferably, the specific steps of high-temperature fuel gas purification in step S2 include: the high-temperature fuel gas enters the cyclone dust collector to separate the particulate pollutants therein under the action of centrifugal force; then enters the cyclone separator tangentially from the airflow to separate the particulate matter therein under the action of inertial centrifugal force to complete the fuel gas purification.

[0017] Preferably, the biomass raw materials include rice straw, wheat straw and forestry waste.

[0018] Beneficial effects:

[0019] In the present invention, the biomass raw material is gasified in the gasifier, and the high-temperature, medium-low calorific value gas generated enters the first waste heat boiler to produce medium-temperature medium-pressure steam, and the steam enters the steam turbine generator set to generate electricity. The cooled gas enters the internal combustion engine generator set to generate electricity, and the high-temperature flue gas passes through the second waste heat boiler to generate steam and enter the steam turbine generator set for combined cycle power generation. The combined operation of the steam turbine generator set and the internal combustion engine generator set increases the flexibility of the system; the cooled gas and the produced steam of the first waste heat boiler are fully utilized, which greatly improves the efficiency of converting biomass energy into electrical energy, reduces energy waste, and significantly improves the comprehensive energy utilization rate of the entire system.

[0020] The present invention uses oxygen as a gasifying agent, and the generated fuel gas contains carbon monoxide (CO) and hydrogen (H 2) The proportion of combustible components such as oxygen is high, the calorific value of the gas is significantly improved, its energy density is higher, the combustion performance is better, and it is more conducive to the subsequent power generation process. Oxygen gasification helps to reduce impurities in the gas. Oxygen gasification is relatively pure, and the subsequent combination with an effective purification unit can make the gas cleaner, reduce the content of impurities such as tar, particulate matter and sulfur, reduce wear and corrosion on internal combustion engines and other equipment, and produce less pollutants such as sulfur dioxide during the combustion process, which helps to reduce pollution to the atmospheric environment and is more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a schematic diagram of the biomass gasification gas-steam combined cycle power generation system of the present invention.

[0023] Description of reference numerals:

[0024] 1-gasifier, 2-cyclone dust collector, 3-cyclone separator, 4-first waste heat boiler, 5-waste heat recovery device, 6-internal combustion engine generator set, 7-second waste heat boiler, 8-steam turbine generator set. DETAILED DESCRIPTION

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0027] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] System Example

[0029] like Figure 1 As shown, a biomass energy gasification gas-steam combined cycle power generation system includes a gasifier 1, the furnace of the gasifier 1 adopts a segmented design, which is divided into a preheating section, a pyrolysis section, an oxidation section and a reduction section. In the preheating section, the waste heat of the high-temperature flue gas is used to preheat the newly entered biomass raw materials, increase the temperature of the raw materials entering the furnace, and reduce the energy required to start the gasification reaction; the pyrolysis section adopts a special spiral pyrolysis device to make the biomass raw materials evenly heated during the rotation process, promote the pyrolysis reaction, and improve the generation rate and quality of the pyrolysis products; an adjustable baffle is set between the oxidation section and the reduction section, and the oxygen supply and airflow speed are adjusted by controlling the opening of the baffle, and the process of oxidation and reduction reactions is accurately controlled, so that the calorific value and output of the generated gas reach the optimal state.

[0030] The gas outlet of the gasifier 1 is connected to the cyclone dust collector 2, the cyclone separator 3 and the first waste heat boiler 4 in sequence. The gas outlet of the first waste heat boiler 4 is connected to the internal combustion engine generator set 6, the gas outlet of the internal combustion engine generator set 6 is connected to the second waste heat boiler 7, and the steam outlets of the first waste heat boiler 4 and the second waste heat boiler 7 are both connected to the steam turbine generator set 8.

[0031] The jacket water outlet of the internal combustion engine generator set 6 is connected to the heat source section inlet of the waste heat recovery device 5, and the heat source section outlet of the waste heat recovery device 5 is connected to the jacket water inlet of the internal combustion engine generator set 6; the heating section inlet of the waste heat recovery device 5 is connected to the condensed water of the power plant.

[0032] The gasifier 1 is a 10 t / h biomass gasifier 1, the internal combustion engine generator set 6 is a 17.5 MW internal combustion engine generator set 6, the second waste heat boiler 7 is a 46 t / h medium temperature and medium pressure parameter waste heat boiler, the first waste heat boiler 4 is an 11 t / h medium temperature and medium pressure parameter waste heat boiler, and the steam turbine generator set 8 is a 12 MW steam turbine generator set. The combined cycle power generation efficiency of the above power generation system exceeds 55%.

[0033] Method Embodiment

[0034] A process for a power generation system of a biomass gasification gas-steam combined cycle power generation system, comprising the following steps:

[0035] S1. Oxygen is input into the gasifier 1 as a gasifying agent, and the biomass raw material is burned as a fuel, generating a temperature of 750-850°C and a calorific value of 10000-15000 kJ / Nm 3 The biomass raw materials include rice straw, wheat straw and forestry waste; preferably, the weight percentage includes 25% rice straw, 25% wheat straw and 50% forestry waste. When oxygen is used as the gasifying agent, the biomass can react more efficiently in the gasifier 1, and the gasification reaction can be carried out at a more suitable oxygen concentration, so that the pyrolysis, oxidation and reduction reactions of the biomass can be carried out more fully, thereby improving the gasification efficiency and increasing the gas production.

[0036] S2. High-temperature fuel gas purification: The high-temperature fuel gas enters the cyclone dust collector 2, and uses the centrifugal force generated by the rotating dust-laden airflow to separate the particulate pollutants therein under the action of the centrifugal force; then the airflow enters the cyclone separator 3 tangentially, so that the solid particles or liquid droplets with large inertial centrifugal force are thrown to the outer wall for separation, thus completing the fuel gas purification;

[0037] After that, it is input into the first waste heat boiler 4, and after heat release and temperature reduction, a sub-high temperature gas of 350-400°C is obtained. The sub-high temperature gas is input into the internal combustion engine generator set 6 to provide energy for the internal combustion engine generator set 6; the medium temperature and medium pressure steam produced by the first waste heat boiler 4 is input into the steam turbine generator set 8 to generate electricity; the high purity and high calorific value gas makes the combustion process of the internal combustion engine more stable and efficient. The internal combustion engine generator set 6 can work under better combustion conditions, reduce incomplete combustion, improve the efficiency of gas work, and thus increase the power output.

[0038] S3. The high-temperature flue gas generated by the internal combustion engine generator set 6 is input into the second waste heat boiler 7. The medium-temperature medium-pressure steam produced by the second waste heat boiler 7 is mixed with the medium-temperature medium-pressure steam produced by the first waste heat boiler 4 and then input into the steam turbine generator set 8 to generate electricity. Since the internal combustion engine has good air intake quality, the exhaust waste heat temperature and energy are relatively high. The second waste heat boiler 7 can produce steam with higher parameters, so that the steam turbine generator set 8 can operate under more efficient working conditions, further improving the power generation efficiency of the entire combined cycle system. The total power generation efficiency of the system is more than 55%, which is significantly improved compared with the single biomass power generation method.

[0039] In the above process, after the high-temperature cylinder jacket water of the internal combustion engine generator set 6 is output, it enters the entrance of the heat source section of the waste heat recovery device 5, is cooled by the heat source section of the waste heat recovery device 5, and then returns to the vicinity of the cylinder jacket of the internal combustion engine generator set 6 to cool the cylinder jacket of the internal combustion engine generator set 6 to complete the cycle.

[0040] A close synergistic relationship is formed between the various devices of the present invention. The gas generated by the gasifier 1 provides an energy source for the subsequent waste heat boiler, internal combustion engine generator set 6 and steam turbine generator set 8; the steam generated by the waste heat boiler generates electricity for the steam turbine generator set 8, and at the same time, the gas is cooled for use by the internal combustion engine generator set 6; the high-temperature flue gas generated by the internal combustion engine generator set 6 can be recycled by the second waste heat boiler 7 to generate steam for power generation, and the waste heat of the cylinder jacket water is recovered through the waste heat recovery device 5 to heat the condensate of the power plant. This coordinated operation between the devices not only improves the energy utilization efficiency of the entire system, but also enables the performance of each device to be fully utilized, improves the overall stability and reliability of the system, and reduces the impact of single equipment failure on power generation.

[0041] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A biomass gasification gas-steam combined cycle power generation system, characterized in that: It includes a gasifier, the gas outlet of the gasifier is connected to a first waste heat boiler, the gas outlet of the first waste heat boiler is connected to an internal combustion engine generator set, the high-temperature flue gas outlet of the internal combustion engine generator set is connected to a second waste heat boiler, and the steam outlets of the first waste heat boiler and the second waste heat boiler are both connected to a steam turbine generator set.

2. The biomass gasification gas-steam combined cycle power generation system according to claim 1, characterized in that: The cylinder jacket water outlet of the internal combustion engine generator set is connected to the inlet of the heat source section of the waste heat recovery device, and the outlet of the heat source section of the waste heat recovery device is connected to the cylinder jacket water inlet of the internal combustion engine generator set; the inlet of the heating section of the waste heat recovery device is connected to the condensed water of the power plant.

3. The biomass gasification gas-steam combined cycle power generation system according to claim 1, characterized in that: A cyclone separator is provided between the gasifier and the first waste heat boiler.

4. The biomass gasification gas-steam combined cycle power generation system according to claim 3 is characterized in that: A cyclone dust collector is provided between the gasifier and the cyclone separator.

5. The biomass gasification gas-steam combined cycle power generation system according to claim 1, characterized in that: The gasifier is a 10t / h biomass gasifier.

6. A power generation process of a biomass gasification gas-steam combined cycle power generation system according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1. oxygen is input into the gasifier as a gasifying agent, and the biomass raw material undergoes a chemical reaction in the gasifier to produce high-temperature combustion gas; S2. The high-temperature gas is purified and input into the first waste heat boiler, the sub-high-temperature gas after heat release and cooling is input into the internal combustion engine generator set, and the medium-temperature and medium-pressure steam produced by the first waste heat boiler is input into the steam turbine generator set to generate electricity; S3. The high-temperature flue gas generated by the internal combustion engine generator set is input into the second waste heat boiler, and the medium-temperature and medium-pressure steam produced by the second waste heat boiler is input into the steam turbine generator set to generate electricity.

7. The power generation process according to claim 6, characterized in that: After the high-temperature cylinder jacket water of the internal combustion engine generator set is output, it enters the inlet of the heat source section of the waste heat recovery device, is cooled by the heat source section of the waste heat recovery device, and then returns to the periphery of the cylinder jacket of the internal combustion engine generator set to complete the cycle.

8. The power generation process according to claim 6, characterized in that: The temperature of the high-temperature gas generated by the gasifier in step S1 is 750-850°C, and the calorific value is 10000-15000 kJ / Nm 3 .

9. The power generation process according to claim 6, characterized in that: The specific steps of high-temperature fuel gas purification in step S2 include: the high-temperature fuel gas enters the cyclone dust collector to separate the particulate pollutants therein under the action of centrifugal force; then enters the cyclone separator tangentially from the airflow to separate the particulate matter therein under the action of inertial centrifugal force to complete the fuel gas purification.

10. The power generation process according to claim 6, characterized in that: The biomass raw materials include rice straw, wheat straw and forestry waste.

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