Method and device for measuring non-soluble iron content of thermodynamic system of thermal power plant unit

Abstract

The invention relates to a method for measuring the non-soluble iron content of a thermodynamic system of a thermal power plant unit. The method comprises the following steps that firstly, a branched pipeline is arranged on a to-be-measured steam water sampling pipeline of the thermodynamic system, and a flowmeter, a microfiltration membrane and a pressure difference transmitter are arranged on the branched pipeline; secondly, the branched pipeline is washed completely, a water sample enters the branched pipeline, the differential pressure change under certain accumulated flow or the increased weight of the microfiltration membrane is recorded, and the colloidal iron fouling index ICFD delta p or ICFD delta m is calculated according to the formula shown in the specification, wherein in the formula, delta p represents differential pressure Pa, S represents the effective area (the unit is square centimeter) of the water sample passing through the microfiltration membrane, V represents the accumulated flow (the unit is cube meter) of the water sample passing through the microfiltration membrane, and delta m represents the increased weight (the unit is gram) of the microfiltration membrane before and after the water sample passes through the microfiltration membrane. By means of the method and device, the content of non-soluble colloidal ferric oxide and particular ferric oxide can be accurately, reliably and continuously monitored, and the corrosion prevention effect and the sedimentation level of the thermodynamic system can be truly reflected.

Description

technical field [0001] The invention belongs to the technical field of boiler feed water treatment for coal-fired units, and in particular relates to a method and device for measuring the content of insoluble iron in a thermal system of a thermal power plant unit. Background technique [0002] Water vapor is the circulating working medium of the thermal equipment of thermal power generating units, and the quality of water vapor is of great significance to the corrosion protection, operating life and safe and economical operation of thermal equipment. GB / T 12145-2008 "Water Vapor Quality of Thermal Power Generating Units and Steam Power Equipment" clearly stipulates various indicators of soda water quality. Among them, the iron content in the thermal system represents the corrosion effect of the equipment, is one of the important indicators for monitoring, and is also one of the key tasks of chemical supervision. Unit overhaul inspection, water wall, economizer pipe cutting,...

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Problems solved by technology

Therefore, although the indication value is accurate when the instrument is calibrated, it is difficult to simulate the insoluble colloidal iron oxide in the actual thermal system, resulting in the false impression that the iron content in the soda water of the thermal system is very low

[0007] 2) Continuous monitoring of iron cannot be realized. Power generation companies usually monitor once a week or two, and the data will be accidental

[0008] 3) Although the online iron meter can realize the continuous monitoring of iron, due to the immature technology development, the application range is small, and the price is expensive, and it is still limited to the monitoring of dissolved ionic iron

The overhaul period of the unit is long, and the daily detection of iron ion concentration cannot reflect the real source of scaling and salt accumulation, and cannot truly reflect the corrosion protection effect of the thermal system

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