CEMS (Continuous Emission Monitoring System) sampling system and method for horizontal flue of main discharge port of coal-fired unit

Abstract

The invention relates to a CEMS (continuous emission monitoring system) sampling system for a horizontal flue at a main discharge port of a coal-fired unit. The CEMS sampling system comprises sampling branch pipes, back flushing electromagnetic valves, sampling electromagnetic valves, a mixing main pipe, flow regulating valves, a dilution unit and a probe controller. A plurality of groups of sampling branch pipes are arranged on the measuring section of a main discharge port flue, a plurality of sampling branch pipes form a group, the lengths of the sampling branch pipes in the same group are arranged in equal difference, and the tops of the sampling branch pipes are equal in height. Each sampling branch pipe is connected to the mixing main pipe through one sampling electromagnetic valve and one flow regulating valve in sequence, and the mixing main pipe is connected to a gas analyzer through the dilution unit and the probe controller in sequence. An outlet pipeline of each sampling branch pipe is connected with a back flushing pipeline, and a back flushing electromagnetic valve is arranged on the back flushing pipeline. The system and the method have the beneficial effects that multi-point sampling is performed at the main discharge port of the coal-fired unit, so that the problem of non-uniform pollutant concentration field caused by a flow field can be eliminated, and the defect that single-point measurement data cannot represent the overall pollutant discharge condition is overcome.

Description

technical field [0001] The invention relates to a sampling system, in particular to a CEMS sampling system and a method for a horizontal flue of a coal-fired unit general outlet. Background technique [0002] In order to strengthen the monitoring and supervision of flue gas emissions from fixed pollution sources (thermal power plant boilers, industrial furnaces, etc., which use solid and liquid as fuel or raw materials), and improve the continuous monitoring and management level of flue gas emissions from fixed pollution sources, all pollutant emission enterprises across the country have installed online Continuously monitor equipment and upload data online. [0003] All the equipment needed to continuously monitor the concentration and discharge of particulate matter and gaseous pollutants from stationary pollution sources, referred to as CEMS. CEMS consists of a particulate matter monitoring unit, a gaseous pollutant monitoring unit, a flue gas parameter monitoring unit, ...

AI Technical Summary

Problems solved by technology

[0004] Due to the early infrastructure construction of some coal-fired power plants, the ultra-low emission transformation of coal-fired units in recent years has used the limited space in the plant area for the addition of environmental protection equipment such as dust removal and desulfurization. There is no redundant land, and the existing units in the plant area are two The furnace shares the same chimney for emission. The monitoring unit is installed in the horizontal flue section before the exhaust gas enters the chimney. The downstream direction of valves and reducing pipes is ≥ 4 times the diameter of the flue, and the upstream direction of the above components is ≥ 2 times the diameter of the flue. Diameter, and the requirement of ≥0.5 times the diameter of the flue from the upstream direction of the above-mentioned components (the rectangular flue is calculated as the equivalent diameter), and there is a large deviation between the CEMS monitoring data and the manual sampling data

Due to the limited horizontal space of the factory area, there is no extra space for flue lengthening and reconstruction, and the cost of chimney reconstruction is too high. Therefore, a technology different from the traditional single-point sampling at the main outlet is needed to solve the above-mentioned problems and ensure the authenticity and reliability of CEMS data.

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