CN103216845A - Deep peak regulation method for thermal power generator set - Google Patents

Abstract

The invention provides a deep peak regulation method for a thermal power generator set. The deep peak regulation method is characterized in that under the condition of being at or below the minimum stable combustion load of the set, atomized ultrafine oil droplets in a small oil gun are ignited by adopting a high-energy igniter, are heated to be gasified in a very short period of time and are then ignited, a high-temperature flame core is produced so as to ignite coal powder, the flame of a big oil gun is replaced with the flame of coal powder airflow through the combustion supporting of the small oil gun, and then, the thermal power generator set is subjected to deep peak regulation. Due to the adoption of the deep peak regulation technology for the thermal power generator set, for the northeast power grid per year, 3 billion kW.h abandoned wind can be utilized, the combustion of coal can be decreased by 999,000 ton, and the emissions can be decreased by 708,900 tons of CO2, 15,242 tons of SO2, 6,133 tons of NOx and 427,088 ton of soot, so that the economic, environmental and social benefits are huge.

Description

Deep peak regulation method for thermal power generating units

technical field

The present invention relates to a deep peak-shaving technology for a thermal power generating set, in particular to a low-fuel combustion-supporting technology under low load or lower than the minimum stable combustion load. Abandon the wind” issue. the

Background technique

Northeast Power Grid With the implementation of the low-carbon economic policy, the proportion of wind power in the power grid has gradually increased. Wind power has surpassed hydropower to become the second largest power source in Northeast Power Grid. The capacity of thermal power grid and the difference between peak and valley loads have surged. At the end of 2011, the total annual power generation of Northeast Grid was 371.874 billion kWh, of which thermal power was 334.163 billion kWh, wind power was 23.737 billion kWh, and hydropower was 13.785 billion kWh. From 2008 to 2011, the actual annual average utilization hours of thermal power units in the Northeast Power Grid decreased from 4709 hours in 2010 to 4584 hours in 2011, a drop of 125 hours. the

Secondly, wind power in Northeast China and even the whole country develops the fastest among clean energy sources. Due to the randomness and intermittent characteristics of wind power output, and its power anti-peaking characteristics are relatively obvious, that is, when the low valley needs to reduce output, and the wind power is in the peak period. state. With the large-scale development of wind power, especially the commissioning of 10-million-kilowatt-scale wind power bases, the peak-shaving problem of the system is very prominent based on the peak-shaving capacity of the existing thermal power units in operation.

In addition, the Northeast is located in the alpine region and the proportion of heating units in the whole network in winter is increasing. It is estimated that by the end of 2015, the peak-shaving capacity of thermal power units will need to be greater than 25%, and the peak-shaving capacity of conventional condensing thermal power units will need to reach more than 55%. The difference increases year by year. the

In addition, the four 1000 MW units of the Hongyanhe Power Station under construction will be put into operation in succession from 2012 to 2015, and nuclear power will basically not participate in peak regulation, which will inevitably intensify the requirements for deep peak regulation of thermal power units.

The Northeast Power Grid has planned 11 sites of 12,500 MW pumped storage power stations, which are still in the site survey stage.

Therefore, under the condition that a large number of abandoned wind power in the Northeast Power Grid is difficult to apply other peak-shaving power sources on a large scale, how to take advantage of the large capacity of thermal power units in the power grid to deeply tap the peak-shaving capacity of thermal power units, adopt unconventional peak-shaving, and improve renewable energy Electric power, the development of deep peak-shaving technology for thermal power, has become a new problem to be solved urgently.

Contents of the invention

Purpose of the invention: The present invention provides a deep peak-shaving method for thermal power generating units, and its purpose is to solve the problem of low utilization rate of renewable energy in the past. the

Technical solution: the present invention is achieved through the following technical solutions:

The deep peak-shaving method of the thermal power generation unit is characterized in that: the method is to use a high-energy igniter to ignite the atomized ultra-fine oil droplets in the micro-oil gun under the minimum stable combustion load of the unit or lower than the minimum stable combustion load. The atomized ultra-fine oil droplets are heated and vaporized in a very short period of time and then ignited to generate a high-temperature "fire core" to ignite the coal powder. Through the combustion support of the small oil gun, the flame of the coal powder flow replaces the flame of the large oil gun. Flame, for deep peak regulation of thermal power generating units.

The thermal power of the oil gun is 465kW. the

Advantages and effects: the present invention provides a deep peak-shaving method for thermal power generating units. The low-oil ignition technology of the present invention is to ignite the atomized ultra-fine oil droplets in a very short period of time after being heated and gasified to generate a high-temperature "fire" nuclear technology to ignite pulverized coal. the

The low-oil ignition technology uses a commonly used high-energy igniter to ignite a micro-oil gun, and then uses the oil gun to ignite the pulverized coal flow, and replaces the flame of the large oil gun with the flame of the pulverized coal flow to achieve the purpose of replacing oil with coal. The thermal power of the oil gun commonly used in low-oil ignition technology is about 465kW, which is far greater than the maximum power of the current domestic plasma generator. Due to the sufficient thermal power, it has a strong adaptability to coal types and can ignite the pulverized coal airflow in time. the

Description of drawings:

Fig. 1 is the schematic diagram of abandoning wind of Liaoning power grid in 2011 of the present invention;

Fig. 2 is the change curve of coal consumption of typical supercritical 600MW unit power supply with load

Figure 3 is a typical subcritical 600MW unit power supply coal consumption change curve with load

Fig. 4 is the change curve of coal consumption of typical subcritical 300MW unit power supply with load

Figure 5 is the change curve of coal consumption with load for ultra-high voltage 200MW unit power supply

Fig. 6 is the variation curve of coal consumption for power supply of ultra-high voltage 135MW unit with load.

The specific embodiment: the present invention will be further described below in conjunction with accompanying drawing:

As shown in Figure 1, the present invention provides a deep peak-shaving method for a thermal power generation unit. The method is to use a high-energy igniter to ignite the atomized gas in the micro oil gun at or below the minimum stable combustion load of the unit. The atomized ultra-fine oil droplets are heated and vaporized in a very short period of time and then ignited to generate a high-temperature "fire core" to ignite the pulverized coal. Through the combustion-supporting of the small oil gun, the pulverized coal flow The flame of the large oil gun replaces the flame of the large oil gun, and performs deep peak regulation on the thermal power generation unit. The thermal power of the oil gun is 465kW.

Ignition with less oil still needs to use a small amount of oil to ignite the pulverized coal flow. Compared with conventional large oil guns, the fuel consumption rate is reduced by about 95%, which has obvious advantages over the reliability and cost of plasma ignition. the

These two technologies are internal combustion burners, which are widely used in domestic large and medium-sized power plants. They can realize boiler oil-free or low-oil ignition and low-load stable combustion. Since the plasma technology started earlier, it has more achievements. the

The main characteristics of the two fuel-saving ignition technologies are shown in Table 1. the

Table 1 Comparison of main features of two fuel-saving ignition technologies

After comparison, it can be seen that the coal type of the plasma burner has weak adaptability, complex system, high initial investment, poor reliability, short cathode life, and high maintenance cost; the coal type of the low-oil ignition burner has strong adaptability, simple system, and low initial investment , strong reliability, long life and low maintenance cost.

The oil-less ignition burner has the functions of low-load stable combustion and main burner. At present, this technology has been applied to unit boilers of various capacities. The combustion methods include tangential combustion direct-flow burners and wall-type combustion swirl burners; pulverizing systems include intermediate storage bin type and direct blowing type. the

Minimum flame stability test without oil injection

The minimum stable combustion load of the boiler given by the boiler factory varies with coal types, boiler types, and unit capacity. Bituminous coal and lignite are abundant in Northeast China, and most of the boilers in the Northeast Power Grid are produced by Harbin Boiler. The minimum stable combustion load of the fixed boiler is roughly: 200MW45%BMCR; 300MW (350MW) 35%BMCR; 600MW and above 30%BMCR. After being converted into the rated load of the unit, it will increase by about 5%, that is, 50% ECR for 200MW; 40% ECR for 300MW (350 MW); 35% ECR for above 600MW. The circulating fluidized bed boiler is 35% ECR. Since the design coal was used in the test, Table 2 shows the test results of the minimum steady combustion load of large boilers in recent years.

The results of the assessment test show that under the condition of the designed coal type, the peak-shaving capacity of all units can reach the value given by the manufacturer. With a certain margin, research shows that this margin is too large. the

Technological and economical experiment of peak load shaving lower than minimum steady combustion load of boiler

With the advancement of low-oil ignition technology for unit boilers (plasma ignition technology still does not break away from the category of micro-oil ignition and low-oil ignition when the boiler is ignited in a cold state), cold ignition in the initial stage of the boiler has been widely used. Due to the high fuel cost , there are still few applications in the deep peak regulation of thermal power units. the

Therefore, if the fuel-less combustion-supporting technology is fully utilized, the small oil gun combustion-supporting technology is adopted at or below the minimum stable combustion load to increase the safety of low-load operation. If calculated according to the unit capacity of about 40 million kilowatts in 2011, the unit will have a reduction space of about 5% to 10%, and the Northeast Power Grid still has a peak-shaving capacity of about 2 million kilowatts to 4 million kilowatts. The problem of curtailment of large amounts of wind power.

Table 2 The results of the minimum steady combustion load and the adjusted minimum load of the boiler without oil input

In 2011, Liaoning Power Grid’s largest wind power shutdown output was 1.62 million kWh (November 23), and the annual abandoned wind power was 562 million kwh, of which 148 million kwh was abandoned in the first quarter and 116 million kwh in the second quarter. 20 million kwh in the third quarter and 278 million kwh in the fourth quarter. The average wind curtailment per quarter is 140.5 million kWh. As shown in Figure 1:

In 2011, the average coal consumption of thermal power units was 333g/kW.h, and the average annual consumption of standard coal was reduced by 187,146t. According to the standard coal unit price of 850 yuan/t in Liaoning area, it is converted into RMB 159.08 million yuan, and the emission of smoke and dust is 80366t, SO ₂ 2868t, NOx1154 t, and CO ₂ 132800.6t.

Suggestions on checking and approving the deep peak load of various units

During the performance assessment of the unit, the design coal type was used and the minimum stable combustion load test could be successfully completed. In actual operation, other factors can be gradually recognized and controlled through technological progress and management, while fuel is affected by the coal market mechanism and coal supply security with the most uncertain factors, the greatest impact, and the most difficult to grasp.

The unit is in the deep peak shaving state, which belongs to unconventional peak shaving. Compared with the conventional peak shaving, the operation of the unit is more complicated and the technical requirements are higher. Therefore, this technical index must be confirmed based on scientific and reasonable data. the

Through in-depth research on the various characteristics of the unit, on the basis of the minimum load stipulated in the "Minimum Operation Mode of Northeast Power Grid Thermal Power Plants (2011)" by the Northeast Electricity Regulatory Bureau, the above factors are combined to further reduce the load of the unit, and the units of different capacities and types The deep peak load is determined as follows: 55% ECR for 200MW; 47% ECR for 300MW (350 MW); 43% ECR for above 600MW; 40% ECR for circulating fluidized bed boilers. the

Among them, the load regulation performance of the circulating fluidized bed coal-fired boiler is better than that of the conventional pulverized coal boiler, and the load changing operation is simple, which is especially suitable for the operation requirements of the power plant boiler. The load regulation performance of power plant boilers depends on the water circulation characteristics, steam temperature characteristics and combustion characteristics under low load conditions. Circulating fluidized bed boilers have obvious advantages in these aspects. The load variation range is large and the adjustment performance is good. The load adjustment range is 100%~25%BMCR, and it can maintain stable combustion even under 25% load. At the same time, the boiler has a high load fluctuation rate, and the change rate is about 6%MCR/min. It has the advantage of deep peak shaving, circulating fluidized bed boilers have large thermal inertia, and AGC has certain difficulties. However, most of the northeast regions are bituminous coal and lignite, and the coal types are more suitable. If the operation measures are appropriate, it can also be realized. Therefore, the circulating fluidized bed boiler is greatly adjusted, and the deep peak load of the circulating fluidized bed boiler is unified to 40% ECR regardless of the capacity. the

In addition, considering that there is a great risk of running a boiler with a fan milling system at a low load, the deep peak load of this type of unit is basically not adjusted, and it is still maintained at 55%~60%. the

See Table 2 for the load of each peaking unit after the deep peaking load is determined. the

Research on economics of unit deep peak regulation

As shown in Figures 2 to 6, Figures 2 to 6 are the variation curves of coal consumption for power supply of typical 135-600MW units with load.

It can be seen from Figure 2 to Figure 6 that when the unit is in peak-shaving operation, with the decrease of the unit load, the coal consumption of power supply increases significantly, and the economy decreases. Therefore, peak-shaving operation of thermal power plants is not economical. the

apply effects

The average minimum load of thermal power units in Northeast Power Grid has been adjusted from about 55% ECR to about 48% ECR now. With the oil gun combustion technology, the average minimum load of the unit increases by 5%ECR-10%ECR, and the peak-shaving capacity of the entire power grid increases by 12%ECR-17%ECR after the deep peak-shaving technology of thermal power units is adopted.

After adopting the deep peak-shaving technology of thermal power units, the entire Northeast Power Grid can use 3 billion kW·h of abandoned wind every year (in 2011, the "abandoned wind" ratio of China's wind power exceeded 12%), reducing coal consumption by 999,000 tons, and reducing 708,900 tons of CO ₂ emissions , SO ₂ 15,242 tons, NOx 6133t, smoke dust 427,088 tons, a total of 849,160,000 yuan in fuel cost savings, huge economic, environmental and social benefits.

Therefore, the adoption of this technology is conducive to the maximum acceptance of renewable energy by the grid, the optimal allocation of energy through the grid, and the minimum primary energy consumption to maximize the exchange for renewable energy and save energy. At the same time maximize energy saving and emission reduction. the

The research on deep peak-shaving technology of thermal power generating units is a multi-disciplinary and multi-specialty project across the power system, covering multiple links in the power system. The deep peak-shaving technology of thermal power generating units is technically feasible. the

Studies have shown that the minimum output of the existing units should be adjusted to: 200MW55% ECR; 300MW (350 MW) 47% ECR; 600MW and above 43% ECR; circulating fluidized bed boiler is 40% ECR. It is technically feasible to adjust the average minimum load of the unit from the original about 55% ECR to the current about 48% ECR, an average increase of 7%. the

Using the small oil gun combustion technology, the Northeast Power Grid can increase the peak-shaving capacity of 2000MW~4000MW. Although the unit economy is reduced, it can effectively solve the problem of a large number of abandoned wind power in wind power, and the overall benefit has increased significantly. the

After adopting the deep peak-shaving technology of thermal power units, the Northeast Power Grid can use 3 billion kW·h abandoned wind every year, reduce coal consumption by 999,000 tons, reduce 708,900 tons of CO ₂ , 15,242 tons of SO ₂ , 6133 tons of NOx, and 427,088 tons of smoke and dust. Economic benefits and environment The benefits and social benefits are huge.

Claims (2)

1. The deep peak-shaving method of the thermal power generation unit is characterized in that: the method is to use a high-energy igniter to ignite the atomized ultra-fine oil droplets in the micro-oil gun at or below the minimum stable combustion load of the unit , the atomized ultra-fine oil droplets are heated and gasified in a very short period of time and then ignited to generate a high-temperature "fire core" to ignite the coal powder. Through the combustion-supporting of the small oil gun, the flame of the coal powder airflow replaces the large oil The flame of the gun is used for deep peaking of the thermal power generation unit. 2. The deep peak-shaving method for a thermal power generating set according to claim 1, characterized in that: the thermal power of the oil gun is 465kW.

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