Method and device for measuring boiler hearth ash fouling coefficient online

Abstract

The invention discloses a method and a device for measuring the boiler hearth ash fouling coefficient online. The method comprises the following steps that (1) under a boiler reference operation state, a three-variable test of a plurality of operation conditions is carried out, and the change rule of the specific flame radiation temperature under the boiler reference state is obtained; (2) under the actual operating state of the boiler, operation parameters including the load of a hearth, the feeding state of a pulverized coal burner, a burner swing angle and the like are measured, and the specific flame radiation temperature is determined under the actual operation state; (3) the flue-gas temperature of the section of the hearth below the flame deflection angle is measured, and accordingto the average value of the flue-gas gas temperature in the section of the hearth and the specific flame radiation temperature in the actual operation state, the average radiation temperature of flames in the boiler is determined; (4) according to inlet and outlet working quality parameters of a water cooling wall evaporation system, the radiant heat flow of the heating surface of the water cooling wall of the hearth is determined; and (5) by utilizing the radiant heat flow of the heating surface of the water cooling wall and the average radiation temperature of the flames in the boiler, the ash fouling efficient of the heating surface of the hearth is determined according to the flame radiation law.

Description

technical field [0001] The invention belongs to the field of operation monitoring and diagnosis of ash accumulation in a boiler furnace, and in particular relates to a method and a device for online measuring the ash coefficient of a heating surface of a furnace. Background technique [0002] The ash accumulation and slagging on the water wall of the boiler furnace increase the heat conduction resistance of the heating tube, the temperature of the tube wall increases, the radiant heat projected to the flame by the heating tube in the opposite direction increases, the heat transfer efficiency of the furnace decreases, and the temperature of the flue gas at the furnace outlet increases. The desuperheating water consumption of the superheater or reheater increases, which reduces the economy and safety of boiler operation. [0003] At present, soot blowers are usually used to remove soot and slagging in the furnace, but soot blowers consume a lot of steam and heat, and frequent ...

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Problems solved by technology

[0006] Therefore, the existing literature on the ash deposition monitoring method on the heating surface of the furnace is mainly based on the flue gas heat balance and heat transfer calculation on the heating surface. This method involves many systems and links, the measurement lag time is long, and the input parameters fluctuate greatly. The furnace thermodynamic calculation model has a large error, and the coal quality data required by the model has not yet been widely measured online, and when the flue gas temperature at the furnace outlet is calculated from the low-temperature flue gas area against the flue gas flow, the heating surfaces at all levels Calculation errors will accumulate on the dirt parameters, resulting in inaccurate monitoring results; currently, the cleaning factor is usually used to represent the relative change of the contamination state of the heating surface, and the resolution of the cleaning factor to the change of the cleanliness of the heating surface is low

[0007] Another defect of the existing furnace pollution state monitoring technology is that the variability of the furnace operating environment is not considered in the monitoring scheme

Essentially, in the above-mentioned literature, the basic principle of furnace contamination state monitoring is that under given operating conditions, the flue gas temperature at the furnace outlet is a single-valued function of the contamination state; in actual operation, the load, combustion Operating parameters such as the swing angle of the furnace, the way of using the pulverized coal nozzle, and the oxygen content of the flue gas at the furnace outlet all affect the temperature of the flue gas at the furnace outlet. changes, and can be applied to the variable operating conditions of the furnace, but none of the above-mentioned documents provides such a technical solution

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