Optimization method for energy-saving control of optimal oxygen content in boiler combustion in thermal power plants

Abstract

The present invention provides an energy-saving control optimization method for the optimal oxygen content of boiler combustion in a thermal power plant, and relates to the technical field of energy-saving control of boilers in thermal power plants. The energy-saving control optimization method for the optimal oxygen content of boiler combustion in a thermal power plant comprises: step one, supplying oxygen to the boiler according to a constant oxygen supply mode, an increasing oxygen supply gradient mode, a decreasing oxygen supply gradient mode, and a fluctuating oxygen supply mode, dividing the temperature into zones according to a temperature gradient of 10 degrees Celsius in the boiler, and dividing the temperature into zones according to a distance gradient of 10 cm from the position of the boiler furnace mouth according to the range of the temperature zone. By determining the position in the boiler where the oxygen supply has the least effect on the combustion temperature and the carbon monoxide concentration and using it as the oxygen supply position, and adjusting the oxygen supply direction during oxygen supply, the oxygen distribution after oxygen supply is more likely to achieve a condition of high heat release and low carbon monoxide content, thereby improving the energy conversion efficiency of the boiler in the thermal power plant.

Description

Technical Field

[0001] The invention relates to the technical field of energy-saving control of thermal power plant boilers, and in particular to an energy-saving control optimization method for optimal oxygen content of thermal power plant boiler combustion. Background Art

[0002] The boiler of a thermal power plant is one of the main thermal equipment in a thermal power plant. It is often matched with a steam turbine generator set of a certain capacity. It is mainly used for power generation, but in some special occasions it can also be used for external heat supply.

[0003] Although the oxygen supply in the boiler can be determined based on the distribution relationship of oxygen, carbon dioxide and carbon monoxide at temperature, the different temperature atmospheres in the boiler also make the concentrations of oxygen, carbon dioxide and carbon monoxide in various parts of the boiler different and irregular, making it impossible to determine the best solution for oxygen supply from the boiler furnace mouth. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the deficiencies in the prior art, the present invention provides an energy-saving control optimization method for optimal oxygen content in thermal power plant boiler combustion, which solves the technical gaps in the prior art caused by the fact that the concentrations of oxygen, carbon dioxide and carbon monoxide in various parts of the boiler are different and irregular.

[0006] (II) Technical solution

[0007] To achieve the above objectives, the present invention is implemented by the following technical scheme: A method for optimizing energy-saving control of optimal oxygen content for boiler combustion in a thermal power plant, comprising the following steps:

[0008] Step 1: supply oxygen to the boiler according to a constant oxygen supply method, an increasing oxygen supply gradient method, a decreasing oxygen supply gradient method, and a fluctuating oxygen supply method, divide the temperature into zones according to a temperature gradient of 10 degrees Celsius in the boiler, and divide the temperature into zones according to a distance gradient of 10 cm from the boiler furnace mouth, and then measure the concentrations of carbon monoxide and oxygen in each temperature positioning zone;

[0009] Step 2: According to the above four oxygen supply methods, the zones are divided and overlapped according to the temperature and the concentrations of oxygen and carbon monoxide, and the range A3 with the highest overlap among the three temperature positioning zones is determined. At each position with the highest overlap, a range A2 with the highest overlap among any two of the temperature, oxygen concentration and carbon monoxide concentration distributed around is established. According to the number of A2 around A3, the best oxygen supply position range A3a within the same distance range from the boiler furnace position is selected, and the oxygen concentration W1 at A3a is recorded;

[0010] Step three, based on A2 containing oxygen concentration around A3a, obtain the corresponding oxygen concentration W2, and then determine the direction of oxygen supply of A3a based on the distribution characteristics of A2 corresponding to W2 in the corresponding A3a, so that at most A2 satisfies W2.

[0011] Preferably, A3, A2, and A3a are all expressed in the form of range coordinates.

[0012] Preferably, the oxygen supply corresponding to the constant oxygen supply mode is the oxygen supply B when the carbon monoxide concentration at the exhaust gas of the boiler is the minimum when the constant oxygen supply is provided at the boiler furnace mouth.

[0013] Preferably, the increasing oxygen supply gradient method is to supply oxygen in a gradient increasing manner of 0.5% starting from the oxygen supply amount B.

[0014] Preferably, the decreasing oxygen supply gradient method is to supply oxygen with an oxygen supply B as the highest point and a decreasing gradient of 0.5%.

[0015] Preferably, the fluctuating oxygen supply method is to perform sawtooth-shaped fluctuating oxygen supply with the oxygen supply B as the fluctuation balance point and 1% as the fluctuation range.

[0016] (III) Beneficial effects

[0017] The present invention provides an energy-saving control optimization method for optimal oxygen content in boiler combustion in a thermal power plant. It has the following beneficial effects:

[0018] In the present invention, by determining the position in the boiler where the combustion temperature and carbon monoxide concentration are least affected by the oxygen supply and using it as the oxygen supply position, and adjusting the oxygen supply direction during oxygen supply, compared with the oxygen supply at the boiler furnace mouth in the prior art, the utilization rate of oxygen is higher, the overall temperature atmosphere and the concentration ranges of carbon dioxide and carbon monoxide are more controllable, and the oxygen distribution after oxygen supply is more likely to achieve a condition with high heat release and low carbon monoxide content, thereby improving the energy conversion efficiency of the boiler in a thermal power plant. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. 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.

[0020] Example:

[0021] The embodiment of the present invention provides a method for optimizing energy-saving control of optimal oxygen content for boiler combustion in a thermal power plant, comprising the following steps:

[0022] Step 1: supply oxygen to the boiler in a constant oxygen supply mode, an increasing oxygen supply gradient mode, a decreasing oxygen supply gradient mode, and a fluctuating oxygen supply mode. The temperature is divided into zones according to a temperature gradient of 10 degrees Celsius in the boiler, and the temperature is positioned and zoned according to a distance gradient of 10 cm from the boiler furnace mouth. The above-mentioned temperature zones are in the form of coordinates with the boiler furnace mouth as the coordinate origin, and the corresponding temperature is marked at the corresponding coordinate range. Then, the concentrations of carbon monoxide and oxygen in each range of the temperature positioning zone are measured. Through the measurement of the concentrations of carbon monoxide and oxygen, the temperature in the boiler The consumption of oxygen and carbon monoxide: the oxygen supply corresponding to the constant oxygen supply mode is the oxygen supply B when the carbon monoxide concentration at the boiler exhaust is the smallest when the constant oxygen supply is supplied at the boiler furnace mouth. This can greatly reduce the emission of carbon monoxide, thereby making the combustion energy release more sufficient. The increasing oxygen supply gradient mode is to supply oxygen with the oxygen supply B as the starting point and in a 0.5% gradient growth mode. The decreasing oxygen supply gradient mode is to supply oxygen with the oxygen supply B as the highest point and in a 0.5% decreasing gradient mode. The fluctuating oxygen supply mode is to supply oxygen in a sawtooth-shaped fluctuation mode with the oxygen supply B as the fluctuation balance point and a fluctuation range of 1%.

[0023] Step 2: According to the above four oxygen supply methods, the zones are divided and overlapped according to the temperature and the concentrations of oxygen and carbon monoxide, and the range A3 corresponding to the temperature positioning zone with the highest overlap of the three concentrations of temperature, oxygen and carbon monoxide is determined. The range A3 is the place in the boiler where the oxygen supply is affected by the above four oxygen supply methods and the combustion is the most stable. At each position with the highest overlap, the range A2 with the highest overlap of any two of the temperature, oxygen concentration and carbon monoxide concentration distributed in the surrounding is established. According to the number of A2 around A3, the best oxygen supply position range A3a within the same distance range from the boiler furnace mouth position is selected, and the oxygen concentration W1 at A3a is recorded, where W1 is the oxygen concentration when oxygen is supplied at A3a;

[0024] Step three, based on A2 containing oxygen concentration around A3a, and obtaining the corresponding oxygen concentration W2, then determine the direction of oxygen supply of A3a according to the distribution characteristics of A2 corresponding to W2 in the corresponding A3a, so that at most A2 satisfies W2. The corresponding method here can be to adjust the joint of the oxygen direction, for example, using a fan-shaped joint can make the oxygen entering the boiler distributed in a fan shape at the position of the fan-shaped joint.

[0025] A3, A2, and A3a are all expressed in the form of range coordinates.

[0026] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for optimizing energy-saving control of optimal oxygen content for boiler combustion in thermal power plants, characterized in that; The following steps are involved: Step 1: supply oxygen to the boiler according to a constant oxygen supply method, an increasing oxygen supply gradient method, a decreasing oxygen supply gradient method, and a fluctuating oxygen supply method, divide the temperature into zones according to a temperature gradient of 10 degrees Celsius in the boiler, and divide the temperature into zones according to a distance gradient of 10 cm from the boiler furnace mouth, and then measure the concentrations of carbon monoxide and oxygen in each temperature positioning zone; Step 2: According to the above four oxygen supply methods, the zones are divided and overlapped according to the temperature and the concentrations of oxygen and carbon monoxide, and the range A3 with the highest overlap among the three temperature positioning zones is determined. At each position with the highest overlap, a range A2 with the highest overlap among any two of the temperature, oxygen concentration and carbon monoxide concentration distributed around is established. According to the number of A2 around A3, the best oxygen supply position range A3a within the same distance range from the boiler furnace position is selected, and the oxygen concentration W1 at A3a is recorded; Step three, based on A2 containing oxygen concentration around A3a, obtain the corresponding oxygen concentration W2, and then determine the direction of oxygen supply of A3a based on the distribution characteristics of A2 corresponding to W2 in the corresponding A3a, so that at most A2 satisfies W2.

2. The method for optimizing energy-saving control of optimal oxygen content for boiler combustion in a thermal power plant according to claim 1, characterized in that: The A3, A2, and A3a are all expressed in the form of range coordinates.

3. The method for optimizing energy-saving control of optimal oxygen content for boiler combustion in a thermal power plant according to claim 1, characterized in that: The oxygen supply corresponding to the constant oxygen supply mode is the oxygen supply B when the carbon monoxide concentration at the boiler exhaust is the smallest when the constant oxygen supply is provided at the boiler furnace mouth.

4. The method for optimizing the energy-saving control of the optimal oxygen content for boiler combustion in a thermal power plant according to claim 3 is characterized in that: The increasing oxygen supply gradient method is to supply oxygen in a gradient increasing manner of 0.5% starting from the oxygen supply amount B.

5. The method for optimizing the energy-saving control of the optimal oxygen content for boiler combustion in a thermal power plant according to claim 3 is characterized in that: The decreasing oxygen supply gradient method is to supply oxygen with the oxygen supply B as the highest point and at a decreasing gradient of 0.5%.

6. The method for optimizing energy-saving control of optimal oxygen content for boiler combustion in a thermal power plant according to claim 3, characterized in that: The fluctuating oxygen supply method is to perform sawtooth-shaped fluctuating oxygen supply with the oxygen supply B as the fluctuation balance point and 1% as the fluctuation range.