WGGH (Water Gas Gas Heater) system

Abstract

The invention discloses a WGGH (Water Gas Gas Heater) system. The system comprises an FGC (Flue Gas Cooler), an FGR (Flue Gas Reheater), a two-point water taking loop and a condensate pipe, wherein one water taking point of the two-point water taking loop is connected to the condensate pipe in front of an eighth low pressure heater, and another water taking point of the two-point water taking loop is connected to the condensate pipe between a sixth low pressure heater and a seventh low pressure heater; the pipeline after water taking of the two-point water taking loop is connected to a first main loop through a main water taking loop. By using a two-point condensate feeding mode, a water return pipeline is additionally arranged to control the mixing temperature after the two-point water taking and guarantee that a heated surface of a heat exchanger is not corroded and the temperature of heat medium water and gas does not deviate from a design value; the environmental protection requirement of zero emission can be guaranteed through the WGGH system; the WGGH system is used as a temperature adjusting system indispensable for super clean emission, so great economic benefit is brought.

Description

technical field [0001] The invention relates to a WGGH system, in particular to a WGGH system involving a new water intake pipeline, which belongs to the technical field of boiler systems. Background technique [0002] Before the appearance of WGGH (water gas heater heat medium water-gas-gas heat exchanger), the boiler process is: the flue gas from the furnace passes through the SCR reactor and then enters the air preheater, and then the flue gas from the air preheater After entering the dust collector, the flue gas after dust removal by the dust collector enters the desulfurization tower, and the flue gas desulfurized by the desulfurization tower is discharged to the atmosphere through the chimney. [0003] Since the temperature of the dust collector is required to be about 95 degrees, and the temperature of the flue gas from the air preheater is about 135 degrees, a separate heat collector is set between the two to cool down, and this section is called the cooling sectio...

AI Technical Summary

Problems solved by technology

[0010]However, the WGGH system has excessive energy consumption in application, low utilization rate, and basically no energy-saving effect. Specifically, the WGGH system has the following deficiencies Where:

[0011]1. FGC lowers the flue gas temperature from 150-160°C to 90-95°C, while FGR raises the temperature of the desulfurized net flue gas from 50°C to 80°C ℃; so the heat absorbed and released by the heat medium water in its internal circulation are not equal; at this time, if there is no corresponding temperature adjustment equipment in the system, the heat medium water will appear after several cycles of heat medium water. The temperature deviates from the design temperature. Under the condition that the heat exchange area of ​​the FGC and FGR heat exchangers is constant, the flue gas temperature at the outlet of the cooling section and the heating section will also deviate from the design temperature, which cannot achieve the original design effect, thus affecting the dust removal efficiency and desulfurization cannot be guaranteed. After net flue gas heating effect, causing chimney corrosion

[0012]2. The existing WGGH system is equipped with an auxiliary steam source, which is used in the initial stage of system startup and when the load is low. Discharge system, at this time, the water temperature of the condensed water in the discharge system is about 110-120°C, direct discharge will lose this part of heat

[0013]3. When the water temperature in the heat medium water internal circulation reaches a constant requirement, the water entering the FGR from the FGC still has to pass through the auxiliary steam heater at full flow to increase the system resistance , resulting in waste of equipment and waste of resources

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