RU2700485C2 - Boiler plant - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to the field of power engineering. Boiler plant includes boiler with exhaust gas flue and exhaust gas recirculation flue connected to exhaust gas flue, i.d. fan and flue gas stack, blow fan, regenerative air heater, exhaust gas recirculation i.d. fan. Deaerator with pipelines for supply of initial and drainage of deaerated water is connected to exhaust gas flue between i.d. fan and flue gas stack along desorbing medium, and exhaust gas recirculation flue is connected to exhaust gas flue between deaerator and flue gas stack.

EFFECT: higher efficiency of boiler plant by excluding steam consumption for deaeration and introduction of flue gases into combustion zone of boiler furnace, which allows reducing temperature in most heat-stressed part of furnace and reducing concentration of oxygen in combustion zone.

1 cl, 1 dwg

Description

The invention relates to the field of boiler technology and can be used in boiler plants operating on natural gas.

An analogue is known - a boiler installation containing a boiler with a flue gas duct and a flue gas recirculation duct connected to a flue gas duct, a smoke exhaust and a chimney, a blower fan, a regenerative air heater, a flue gas recirculation smoke exhaust (see Improving the environmental safety of thermal power plants: Textbook. A manual for universities / A.I. Abramov, D.P. Elizarov, A.N. Remezov and others; edited by A.S. Sedlov. - M.: MEI Publishing House, 2001, Fig. 4.4 on p. 100 and description to it). This analogue is adopted as a prototype.

The disadvantage of the analogue and prototype is the reduced environmental safety due to the increased content of harmful substances during the combustion of fuel, in particular, nitrogen oxides NO _x , in the exhaust gases of the boiler, and the reduced efficiency of the boiler plant due to the cost of steam for deaeration.

The technical problem to which the invention is directed is the development of a boiler plant with increased efficiency and environmental safety.

The technical result is an increase in the efficiency of the boiler plant by eliminating steam costs for deaeration and improving environmental safety by introducing a mixture of exhaust gases and corrosive gases released during the deaeration into the combustion zone of the boiler furnace, which reduces the temperature in the most heat-stressed part of the furnace and reduces the concentration nitric oxide NO _x in the combustion zone.

To achieve a technical result, a boiler plant is proposed comprising a boiler with a flue gas duct and a flue gas recirculation duct connected to a flue gas duct, a smoke exhaust and a chimney, a blower fan, a regenerative air heater, and a flue gas recirculation smoke exhauster.

The peculiarity lies in the fact that a deaerator with pipelines for supplying the source and removal of deaerated water is connected to the exhaust gas duct of the boiler between the exhaust fan and the chimney, and the exhaust gas recirculation duct is connected to the exhaust gas duct between the deaerator and the chimney.

The use of a boiler exhaust gas as a desorbing agent in a deaerator, which practically does not contain corrosive oxygen, eliminates the cost of steam for deaeration and utilizes the heat of the exhaust gases. Carbon dioxide in deaerated water is neutralized by dosing an alkaline agent, for example sodium hydroxide. The mixture of exhaust gases and corrosive gases and water vapors released during the deaeration after the deaerator is sent to the boiler furnace through the exhaust gas recirculation duct. This reduces the combustion temperature in the furnace and reduces the formation of nitrogen oxides NO _x during fuel combustion.

Next, we consider the information confirming the possibility of carrying out the invention with obtaining the desired technical result.

The schematic diagram of the boiler installation is shown in the drawing. The boiler installation comprises a boiler 1, a flue gas duct 2, a smoke exhauster 3, a deaerator 4, connected via a desorption medium to a flue gas duct 2 between a smoke exhauster 3 and a chimney 5. A pipe 6 for supplying raw water is connected to the upper part of the deaerator 4 column. A pipe 7 for discharging deaerated feed water is also connected to the deaerator 4, into which the feed pump 8 is connected. An alkaline agent dosing system 9 is connected to the pipe 7 of the deaerated feed water. The blower fan 10 directs air to the regenerative air heater 11. An exhaust gas recirculation duct 12 is connected to the flue gas duct 2 between the deaerator 4 and the chimney 5, into which a flue exhaust gas recirculation fan 13 is connected. A pipe 14 for supplying natural gas is connected to the furnace of boiler 1.

The boiler installation works as follows.

The flue gases of the boiler 1 used as a stripping agent from the flue gas duct 2 after the exhaust fan 3 are fed to the lower part of the deaerator column 4. The flue gases, rising upward inside the deaerator structure, cross the water jets, heating the source water to saturation temperature, and release corrosive gases and mixing the latter with a desorbing agent. The mixture of exhaust gases and corrosive gases and water vapors released from the source water is removed from the upper part of the deaerator column 4 through the flue gas duct 2 into the chimney 5. Thus deaerated water is discharged from the deaerator 4 by means of the feed pump 8, and the dosing system 9 passes alkaline agent (sodium hydroxide), which helps to remove corrosive carbon dioxide from water. Then the deaerated water is supplied to the economizer of boiler 1. A gas mixture of exhaust gases and emitted corrosive gases, water vapor after the deaerator 4 through the exhaust gas recirculation duct 12 is sent to the upper part of the furnace 1 by means of a flue exhaust gas recirculation 13, which reduces the concentration oxygen in the combustion zone of the fuel and reduce the temperature of combustion.

The blower fan 10 injects primary air, which is heated in a regenerative air heater 11 before being fed into the furnace of the boiler 1 and mixed with natural gas, which enters through the natural gas supply line 14.

The proposed boiler installation allows you to increase the efficiency of the process of deaeration of water by eliminating the cost of steam for deaeration, as well as to utilize the heat of the exhaust gases of the boiler by lowering their temperature before being discharged into the atmosphere in the deaerator 4. Simultaneous reduction of the temperature of combustion of fuel in the furnace of boiler 1 and, as a result, reduction of nitrogen oxides NO _x in the combustion process and their subsequent release into the atmosphere, is achieved by adding the mixture of flue gas and precipitated in the deaerator corrosion-acti gases and water vapor through the gas duct 12, the flue gas recirculation in the boiler furnace 1, reducing adverse effects on the climate system, and enhances the environmental safety of the boiler plant at an economical operation of the equipment.

Claims (1)

A boiler plant comprising a boiler with a flue gas duct and a flue gas recirculation duct connected to a flue gas duct, a smoke exhaust and a chimney, a blower fan, a regenerative air heater, a flue exhaust gas recirculation fan, characterized in that in a boiler flue gas duct between the smoke exhaust and a smoke exhaust the pipe through the desorbing medium includes a deaerator with pipelines for supplying the source and removal of deaerated water, and the flue gas recirculation duct is connected to the flue gas duct between in de-aerator and a chimney.

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