Zero flue gas emission closed loop power plant flue gas treatment method and system

Abstract

The present application relates to power plant reaction gas circulation treatment technical field, specifically to a kind of zero flue gas emission's closed loop power plant flue gas treatment method and system.Method includes conveying air and coal powder to combustor and burning, according to the oxygen wind ratio of determination oxygen is input to combustor auxiliary combustion;Flue gas discharged by combustor is heated to set temperature, purification treatment is carried out and separates out carbon dioxide, water, nitrogen and oxygen, wherein oxygen is collected and re-delivered to combustor auxiliary combustion to recycle.The present application can be according to the oxygen wind ratio of oxygen redistribution delivery, improve the combustion efficiency of oxygen delivery into combustor, thereby reducing the appearance of other combustion products, guarantee the composition ratio of combustion product, and form closed flue gas treatment structure, extract processing multiple components in flue gas, wherein oxygen is recycled to be used as auxiliary combustion, energy saving and emission reduction are realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power plant reaction gas recycling processing technology, in particular to a zero flue gas emission closed loop power plant flue gas treatment method and system. BACKGROUND

[0002] The coal-fired power plant generally uses coal as the raw material for power generation, and the amount of carbon dioxide emitted during power generation is very large. The current carbon dioxide capture technology is still in the research and test stage, and its capture and utilization are limited. In this case, the coal-fired power plant has the problems of large amount of carbon dioxide emission leading to environmental pollution, and high cost and large amount of carbon dioxide treatment, which greatly increases the operating cost of the coal-fired power plant and also causes great pressure on the environment. There are currently systems for real-time monitoring of gas emissions, but they can only monitor the amount of carbon dioxide emissions and cannot directly promote the reduction of carbon dioxide emissions. Other solutions for capturing and processing carbon dioxide can only provide some relief and cannot fundamentally solve the current problems.

[0003] It can be seen that the flue gas treatment and emission of the current coal-fired power plant still needs to be improved, and needs to be optimized to reduce the emission of carbon dioxide and improve the effect of flue gas treatment. Therefore, a more reasonable technical solution is needed to solve the technical problems in the prior art. SUMMARY

[0004] To overcome at least one of the above-mentioned defects, the present application proposes a zero flue gas emission closed loop power plant flue gas treatment method and system, which purifies the boiler flue gas and separates carbon dioxide, nitrogen, water and oxygen. Carbon dioxide and nitrogen can be used as raw materials and sent to a chemical plant for resource utilization, and oxygen can be returned to the boiler for reburning, thereby increasing the oxygen content in the air required for boiler combustion and ensuring an oxygen-rich combustion environment.

[0005] To achieve the above-mentioned purpose, the flue gas system disclosed in the present application can adopt the following technical solution:

[0006] A zero flue gas emission closed loop power plant flue gas treatment method, comprising:

[0007] delivering air and coal powder to the burner and burning, inputting oxygen auxiliary combustion into the burner according to a determined oxygen-air ratio;

[0008] raising the flue gas discharged from the burner to a set temperature, purifying and separating carbon dioxide, water, nitrogen and oxygen, collecting the oxygen and re-delivering it to the burner for auxiliary combustion for recycling.

[0009] The flue gas treatment method disclosed above separates multiple air components from the flue gas of the burner, determines the oxygen demand of the burner according to the combustion condition, adjusts the delivery amount of air and oxygen, promotes the full combustion of the pulverized coal and obtains the specified multiple products, facilitates the subsequent treatment and collection of the flue gas, determines the oxygen demand and sends the separated oxygen to the burner for reaction again, helps form a closed circulation system, reduces the environmental pollution, and improves the efficiency of the flue gas treatment and the utilization rate of the raw materials.

[0010] Further, the treatment method disclosed above can accurately deliver oxygen to the burner after determining the oxygen-air ratio, and the method for determining the oxygen-air ratio is not uniquely limited. When the oxygen is input to the burner as auxiliary combustion, the oxygen-air ratio is determined according to the following method

[0011]

[0012] m = 1 + 0.0016d

[0013]

[0014] wherein O air is the oxygen-air ratio coefficient, is the oxygen concentration, d is the air humidity, a is the excess air coefficient, and m and n are intermediate substitution numbers. When this scheme is adopted, the factors for determining the oxygen-air ratio do not include the coal quality.

[0015] Further, in order to improve the efficiency of combustion, the oxygen needs to be rapidly combusted after entering the burner to reduce the occurrence of intermediate products. Here, optimization is performed and one of the feasible options is proposed: the oxygen is heated to reach a set temperature before being input to the burner as auxiliary combustion. When this scheme is adopted, the heated oxygen can reach the temperature of the secondary air and be input to the burner in the form of secondary air.

[0016] Further, the temperature of the flue gas discharged from the burner cannot meet the requirements of subsequent treatment, so the flue gas needs to be reprocessed to enable the temperature of the flue gas to reach a certain level for reprocessing. The reprocessing method of the flue gas is not uniquely limited, and here optimization is performed and one of the feasible options is proposed: the flue gas discharged from the burner is heated to a set temperature, including using a superheater, a coal economizer, and an air preheater. When this scheme is adopted, the temperature of the flue gas is adjusted to the required temperature value by the temperature regulation of the superheater, the coal economizer, and the air preheater in sequence.

[0017] Further, the purification method of the flue gas is not limited to the above-mentioned method, and the purification method of the flue gas is optimized and one of the possible methods is provided as follows: the purification method of the flue gas includes collecting carbon dioxide by carbon collection and collecting water by dehumidification separation. In this way, carbon dioxide, water, nitrogen and oxygen are separated and transported.

[0018] The above-mentioned method for treating flue gas is disclosed, and the present application further provides a flue gas treatment system.

[0019] A zero-flue-gas-emission closed-loop power plant flue gas treatment system includes:

[0020] A combustion unit includes a burner for mixing and burning raw materials, and the burner is connected to a coal powder source, an air source and an oxygen source respectively.

[0021] A temperature adjusting unit is in communication with the combustion unit and used for introducing flue gas into the combustion unit, and the temperature adjusting unit is used for adjusting the temperature of the flue gas to a set temperature value.

[0022] A purification unit is in communication with the temperature adjusting unit and used for separating and collecting the flue gas, and the purification unit is used for separating carbon dioxide, water, nitrogen and oxygen from the flue gas.

[0023] An oxygen delivery line is in communication with the purification unit and used for adjusting and delivering the separated oxygen to the combustion unit, and the oxygen delivery line includes an oxygen storage device and a direct delivery pipeline arranged in parallel with the oxygen storage device.

[0024] The above-mentioned flue gas treatment system can reprocess the flue gas discharged from the combustion unit, separate the flue gas into multiple individual components, and transport and use the individual components respectively. In particular, the oxygen-air ratio is determined according to the combustion condition, the oxygen is delivered to the burner according to the accurate delivery amount, the efficiency of the coal powder combustion is improved to form suitable products, the pollution to the environment is reduced, and stable combustion and flue gas circulation are realized in the closed-loop system.

[0025] Further, the temperature adjusting unit includes a superheater, and the superheater is in communication with the burner and used for heating the flue gas to a first set temperature.

[0026] Further, in the present application, the heat that is not fully utilized is utilized in addition to the temperature adjustment of the flue gas by the superheater, and one of the possible methods is provided as follows: the temperature adjusting unit includes an economizer, and the economizer is used for heat exchange with a boiler to adjust the temperature of the flue gas to a second set temperature.

[0027] Further, the temperature adjusting part includes an air preheater, which is communicated with the coal economizer and adjusts the temperature of the flue gas to a third set temperature.

[0028] Further, when the flue gas is treated by the system, the circulating oxygen needs to be adjusted in temperature before entering the combustor, which facilitates to improve the reaction rate of the oxygen entering the combustor and the combustion rate of the pulverized coal, thereby avoiding the generation of other combustion products and reducing the pollution and damage to the environment.

[0029] Compared with the prior art, some beneficial effects of the technical scheme of the present application include:

[0030] The present application can redistribute and deliver the oxygen according to the oxygen / air ratio, improve the combustion efficiency of the oxygen delivered into the combustor, thereby reducing the generation of other combustion products, ensuring the composition ratio of the combustion products, and forming a closed flue gas treatment structure to extract and treat multiple components in the flue gas, and recycle the oxygen to assist combustion, thereby achieving energy saving and emission reduction. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the drawings needed in the embodiments will be briefly introduced as follows, and it should be understood that the following drawings only represent some embodiments of the present application, and should not be regarded as a limitation on the scope, and for those skilled in the art, other related drawings can be obtained without creative labor.

[0032] Figure 1 The figure is a schematic diagram of the components of the treatment system. DETAILED DESCRIPTION

[0033] The present application will be further explained in conjunction with the drawings and specific embodiments.

[0034] The existing thermal power plant produces flue gas containing a large amount of carbon dioxide, which is difficult to separate and capture, resulting in environmental pollution and damage, and other components cannot be reasonably used, causing waste of resources. The following embodiments are optimized to overcome the defects in the prior art.

[0035] Embodiment 1

[0036] The present embodiment provides a zero-flue-gas-emission closed-loop power plant flue gas treatment method, comprising:

[0037] Air and coal powder are delivered into the burner and combusted, and oxygen is input into the burner as auxiliary combustion according to a determined oxygen-air ratio;

[0038] The flue gas discharged from the burner is heated to a set temperature, purified, and separated into carbon dioxide, water, nitrogen, and oxygen, and the oxygen is collected and delivered into the burner as auxiliary combustion for recycling.

[0039] The flue gas treatment method disclosed in the embodiment separates various air components from the flue gas of the burner, determines the oxygen demand of the burner according to the combustion condition, adjusts the delivery amount of air and oxygen, promotes the complete combustion of coal powder, and obtains specified products, thereby facilitating the subsequent treatment and collection of flue gas; the oxygen demand is determined, and the separated oxygen is delivered into the burner for reaction again, thereby forming a closed circulation system, reducing environmental pollution, and improving the efficiency of flue gas treatment and the utilization rate of raw materials.

[0040] The treatment method disclosed in the embodiment can accurately deliver oxygen into the burner after determining the oxygen-air ratio, and the method for determining the oxygen-air ratio is not uniquely limited; when the burner is input with oxygen as auxiliary combustion, the oxygen-air ratio is determined according to the following method

[0041]

[0042] m = 1 + 0.0016d

[0043]

[0044] wherein O air is the oxygen-air ratio coefficient, is the oxygen concentration, d is the air humidity, a is the excess air coefficient, and m and n are intermediate substitution numbers. When this scheme is adopted, the factors for determining the oxygen-air ratio do not include the coal quality.

[0045] Preferably, according to the formula, all the separated oxygen in the flue gas is used to supplement the boiler combustion, and the oxygen-air ratio coefficient is related to the air humidity, the excess air coefficient, and the separated oxygen concentration, and is irrelevant to the coal quality composition and the like burned.

[0046] According to the design parameters of the coal-fired power plant, the oxygen-air ratio coefficient can be calculated. For example, when the excess air coefficient is 1.27, the air humidity is 86.5%, and the oxygen concentration is 99%, the oxygen-air ratio coefficient can be calculated as 5.11%, that is, when the oxygen-air ratio is 5.11%, the oxygen in the flue gas can be reused by using oxygen-enriched combustion.

[0047] At this time, the oxygen-enriched combustion is equivalent to the oxygen content in the air being 24.79%.

[0048] The carbon dioxide concentration is increased by about 1%, the flue gas heat loss is reduced by about 1.2%, and the overall performance of the boiler is improved.

[0049] In order to improve the efficiency of combustion, it is necessary to make oxygen enter the combustor quickly after combustion to reduce the appearance of intermediate products, and here one of the feasible options is optimized and proposed: before the oxygen combustion is input into the combustor, the oxygen is heated to reach the set temperature. When this scheme is adopted, the heated oxygen can reach the temperature of the secondary air and be input into the combustor in the form of secondary air.

[0050] The flue gas temperature discharged from the combustor cannot meet the needs of subsequent treatment, so the flue gas needs to be reprocessed to make the flue gas temperature reach a certain level to facilitate reprocessing. The reprocessing method of flue gas is not uniquely limited, and here one of the feasible options is optimized and proposed: the flue gas discharged from the combustor is heated to a set temperature, including using a superheater, a coal economizer and an air preheater. When this scheme is adopted, the flue gas is sequentially adjusted by the temperature of the superheater, the coal economizer and the air preheater, so that the flue gas temperature can be adjusted to the required temperature value.

[0051] When the flue gas is purified, the method is not uniquely limited, and the embodiment optimizes and adopts one of the feasible options: the purification of the flue gas includes collecting carbon dioxide by carbon collection and collecting water by dehumidification separation. When this scheme is adopted, carbon dioxide and water are separated, and nitrogen and oxygen are also separated. Finally, carbon dioxide, water, nitrogen and oxygen are respectively transported and used.

[0052] Embodiment 2

[0053] The above disclosure discloses a flue gas treatment method, and the present application also provides a flue gas treatment system.

[0054] Specifically, as shown in Figure 1 A zero-flue-gas-emission closed-loop power plant flue gas treatment system, comprising:

[0055] A combustion unit, comprising a combustor for mixing and burning raw materials, the combustor being connected to the sources of coal powder, air and oxygen respectively;

[0056] A temperature adjusting unit in communication with the combustion unit and used to introduce flue gas into the combustion unit, the temperature adjusting unit being used to adjust the temperature of the flue gas to a set temperature value;

[0057] A purification unit in communication with the temperature adjusting unit and used to separate and collect the flue gas, the purification unit being used to separate carbon dioxide, water, nitrogen and oxygen from the flue gas;

[0058] The oxygen delivery line, which is in communication with the purifying unit, is used to regulate and deliver the separated oxygen to the combustion unit, and comprises an oxygen storage device and a direct delivery pipeline arranged in parallel with the oxygen storage device.

[0059] The flue gas treatment system disclosed above can reprocess the flue gas discharged from the combustion unit, separate the flue gas into multiple individual components, and deliver and utilize the individual components respectively. In particular, the oxygen-air ratio is determined according to the combustion condition, and the oxygen is delivered to the combustor at an accurate delivery amount, so as to improve the efficiency of the pulverized coal combustion, form suitable products, reduce the pollution to the environment, and stabilize the combustion and flue gas circulation in the closed loop system.

[0060] In the embodiment, the temperature regulation can be achieved by using various structures. The embodiment is optimized and one of the feasible options is used: the temperature regulation unit comprises a superheater, which is in communication with the combustor and heats the flue gas to a first set temperature.

[0061] In the embodiment, in addition to using the superheater to regulate the temperature of the flue gas, the heat that cannot be fully utilized is also utilized. The embodiment is optimized and one of the feasible options is used: the temperature regulation unit comprises an economizer, which is used in cooperation with the boiler to exchange heat and regulate the temperature of the flue gas to a second set temperature.

[0062] The embodiment is further optimized and one option is used: the temperature regulation unit comprises an air preheater, which is in communication with the economizer and regulates the temperature of the flue gas to a third set temperature.

[0063] When the flue gas is treated by using the system, the circulating oxygen needs to be regulated in temperature before entering the combustor, so as to improve the reaction rate of the oxygen entering the combustor and improve the combustion rate of the pulverized coal, thereby avoiding the generation of other products in the combustion and reducing the pollution and damage to the environment. The heating method is not uniquely limited, and the embodiment is optimized and one of the feasible options is used: a warm oxygen device is further arranged on the oxygen delivery pipeline, and the oxygen delivered by the oxygen storage device and the direct delivery pipeline enters the warm oxygen device and is exchanged to a set temperature before being delivered to the combustion unit.

[0064] The above is the embodiment listed in the embodiment, but the embodiment is not limited to the optional implementation manner described above. Those skilled in the art can obtain other various implementation manners by arbitrarily combining the above manners with each other. Any person can obtain other various forms of implementation manners under the inspiration of the embodiment. The specific implementation manners should not be understood as a limitation on the protection scope of the embodiment, and the protection scope of the embodiment should be defined by the claims.

Claims

1. A zero flue gas emission closed loop power plant flue gas treatment method, characterized by, The application relates to a method for recycling oxygen in a combustion process, comprising the following steps: air and coal powder are delivered into a burner and combusted, and oxygen is input into the burner as auxiliary combustion according to a determined oxygen-air ratio; flue gas discharged from the burner is heated to a set temperature, purified, and separated into carbon dioxide, water, nitrogen and oxygen, wherein the oxygen is collected and delivered into the burner as auxiliary combustion for recycling; when the oxygen is input into the burner as auxiliary combustion, the oxygen-air ratio is determined according to the following method: wherein, is the oxygen ratio coefficient, is the oxygen concentration, is the air humidity, is the excess air coefficient, , is the intermediate number of substitutions.

2. The zero flue gas emission closed loop power plant flue gas treatment method as claimed in claim 1 wherein: before the oxygen is input into the burner as auxiliary combustion, the oxygen is heated to a set temperature.

3. The zero flue gas emission closed loop power plant flue gas treatment method as claimed in claim 1 wherein: the flue gas discharged from the burner is heated to a set temperature, including heat exchange by a superheater, a coal economizer and an air preheater.

4. The zero flue gas emission closed loop power plant flue gas treatment method as claimed in claim 1 wherein: the flue gas is purified, including carbon dioxide collection by carbon capture and water collection by dehumidification separation.

5. A zero flue gas emission closed loop power plant flue gas treatment system for implementing the zero flue gas emission closed loop power plant flue gas treatment method of any one of claims 1 to 4, characterized in that, The application relates to a combustion device for recycling oxygen in a combustion process, comprising the following parts: a combustion part comprising a burner for mixing and combusting raw materials, wherein the burner is connected with the sources of coal powder, air and oxygen respectively; a temperature adjusting part in communication with the combustion part and used for introducing flue gas into the combustion part, wherein the temperature adjusting part is used for adjusting the temperature of the flue gas to a set temperature value; a purification part in communication with the temperature adjusting part and used for separating and collecting the flue gas, wherein the purification part is used for separating carbon dioxide, water, nitrogen and oxygen from the flue gas; an oxygen delivery line in communication with the purification part and used for adjusting and delivering the separated oxygen into the combustion part, wherein the oxygen delivery line comprises an oxygen storage device and a direct delivery pipeline arranged in parallel with the oxygen storage device.

6. The zero flue gas emission closed loop power plant flue gas treatment system as claimed in claim 5 wherein: the temperature adjusting part comprises a superheater in communication with the burner and used for heating the flue gas to a first set temperature.

7. The zero flue gas emission closed loop power plant flue gas treatment system as claimed in claim 6 wherein: the temperature adjusting part comprises a coal economizer in cooperation with a boiler and used for heat exchange to adjust the temperature of the flue gas to a second set temperature.

8. The zero flue gas emission closed loop power plant flue gas treatment system as claimed in claim 7 wherein: the temperature adjusting part comprises an air preheater in communication with the coal economizer and used for adjusting the temperature of the flue gas to a third set temperature.

9. The zero flue gas emission closed loop power plant flue gas treatment system as claimed in claim 6 wherein: the oxygen delivery line is further provided with a warm oxygen device, wherein the oxygen delivered by the oxygen storage device and the direct delivery pipeline is introduced into the warm oxygen device and heated to a set temperature before being delivered into the combustion part.

Images