RU1768862C - Boiler plant - Google Patents

Abstract

Use: in boilers for a more complete use of the heat of combustion products. The inventive products of combustion through parallel chimneys enter the contact economizer 3 and the contact heat exchanger 5, where they are in contact with water supplied through the sprinkler 6 and flowing into the pan 7, forming with the additional sprinkler 12 and the pallet 10 contact air heater circulation circuit Chilled and moisture-saturated flue gases from the heat exchanger 5 are fed to the furnace 1 by a recirculation fan 8, reducing the formation of nitrogen oxides. 1 ill.

Description

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The invention relates to energy and can be used in boilers including a contact air heater.

Boiler plants with flue gas recirculation are known. A disadvantage of the known boiler plants is the insufficient efficiency of reducing the formation of nitrogen oxides at low consumption of recirculation gases, which leads to a decrease in the efficiency of the operation of boiler units.

The closest in technical essence and accepted for the prototype is a boiler plant containing a water heat exchanger connected by a heated duct to a contact air heater, and a heating one - to a contact economizer installed together with a surface heater in the boiler’s flue gas duct, and also for the purpose increase efficiency by making better use of the heat of the combustion products and increase the amount of condensate produced, the installation further comprises a contact heater, Saver pin provided on gases predvklyu- chennoy stage, the pin heater is connected to the gas inlet of the flue gas path to the boiler surface heater, output - to the contact economizer through the upstream stage, and the water - to the heater surface to form a circulation circuit.

A well-known boiler plant due to saturation of flue gases with water vapor makes it possible to obtain a sufficient amount of condensate to feed the heating system without violating the combustion mode in the boiler without using a chemical water treatment system, however, it has the following disadvantage.

It is known that in the combustion chamber of a boiler, when a fuel is burned, environmentally harmful substances are formed, including, in particular, nitrogen oxides. Typically, boiler plants contain structural elements designed to reduce or prevent the formation of nitrogen oxides. Such elements are absent in the known boiler plant, which is its main disadvantage.

An object of the invention is to increase profitability by reducing the formation of nitrogen oxides.

The goal is achieved in that a boiler plant comprising a contact air heater with a sprinkler,

connected by a hot air duct to the boiler furnace, as well as a contact economizer installed in the gas duct, and a contact heat exchanger with water and gas paths, the input section of the latter of which is connected to the gas duct in front of the economizer, is equipped with a recirculation fan and an additional sprinkler, installed in the air heater, the latter is connected via a heating medium through an additional sprinkler to the water path of the heat exchanger with the formation of a circulation loop, and the recirculator ion fan installed in the gas path outlet portion of heat exchanger, the latter being connected to the boiler furnace.

SUMMARY OF THE INVENTION

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It is known that the supply of recirculation gases to the combustion space leads to a decrease in the formation of nitrogen oxides. The most effective reduction in education

nitrogen oxides with a recirculation coefficient, 2, where r is the ratio of the volume of recirculation gases to the total volume of gas and air. However, when supplying 1% of recirculation gases, the efficiency of the boiler of a power plant for

average conditions are reduced by 0.02%. It is also known that the combined supply of recirculation gases and water to the combustion chamber increases the effect of suppressing the formation of nitrogen oxides. However, with

simultaneous but separate supply of water and recirculation gases, a violation of the aerodynamics of the torch is observed and there is a need to control the flow of water depending on temperature and flow

gas recirculation. If a certain optimal ratio is violated, the efficiency of the suppression of nitrogen oxides decreases,

It is also known that effective suppression of nitrogen oxides occurs when moisture is supplied to the root of the torch. During the operation of the boiler, operational parameters (fuel and air consumption,

excess air coefficient, etc.) vary. When changing the operating parameters, the torch root changes its position in the working space. And water at the same time is supplied to the same place

combustion chamber. The mismatch between the torch root and the water inlet area necessitates an increase in water flow to effectively suppress the formation of nitrogen oxides and to reduce the efficiency of the boiler as a whole.

The proposed boiler plant contains a heat exchanger with an additional irrigation device, in which partial cooling and saturation of recirculation gases with moisture occurs. Lowering the temperature of the recirculation gases and saturating them with moisture can reduce the consumption of recirculation gases with the same effect, reducing the formation of nitrogen oxides, which means reducing operating costs and increasing the efficiency of the boiler plant as a whole. In addition, lowering the temperature of the recycle gases makes it possible to use a fan rather than a smoke exhaust as a flow inducer, which also leads to a reduction in one-time and operating costs. The heat taken by the water from the recirculation gases in the heat exchanger apparatus is partially returned to the combustion chamber with the air heated by this water in the air heater.

Thus, the introduction of an additional sprinkler of the heat exchanger placed in the recirculation gas path allows reducing the formation of nitrogen oxides by introducing moisture together with the gas and increasing the efficiency of the boiler plant in comparison with the simultaneous but separate introduction of moisture and recirculation gases.

The drawing schematically shows the proposed boiler plant. ,

The installation comprises a furnace 1 connected by an air duct with a contact air heater 2 and a chimney with a contact economizer 3. The chimney is connected by an outlet 4 to the input of the contact heat exchanger 5 having an irrigator 6 and a tray 7. The output of the contact heat exchanger 5 is connected to the input of the furnace 1 by a flue, in which a recirculation fan is installed 8. The sprinkler 6 of the contact heat exchanger 5 is connected by the route in which the pump 9 is installed to the pallet 10 of the contact air heater 2. The pallet 7 of the contact heat - the exchanger 5 is connected by a route in which a pump 11 is installed to an additional sprinkler 12 of a contact air heater 2. Valves are installed to control the flow rates in the water routes.

Installation works as follows.

Heated air enters the furnace 1 from the contact air heater 2 and

separate fuel (not shown in the drawing). The combustion products through the chimney enter the contact economizer 3. Part of the combustion products through the outlet 4 enters the input of the contact heat exchanger 5, in which they come into contact with water supplied through the sprinkler 6 and flowing after contact with the recirculation gases into the tray 7. Due to water contact gases

recirculations are partially cooled and saturated with moisture. Cooled and saturated with moisture gases recirculation by a recirculation fan 8 is fed to the inlet of the furnace 1. Cold water enters the sprinkler 6 of the contact heat exchanger 5 under the action of the pump 9 from the pallet 10 of the contact air heater 2. From the pallet 7 of the contact heat exchanger 5, hot water under

the action of the pump 11 enters the additional sprinkler 12 of the contact air heater 2, in which it transfers part of the heat to the heated air. Water flows through sprinkler 6 and 12 are controlled by valves installed in the respective paths. Cooled and saturated with moisture in the contact heat exchanger 5 recirculation gases entering the furnace 1. reduce the formation of nitrogen oxides, and return

part of the heat taken from the recirculation gas in the contact heat exchanger, the heated air in the contact air heater increases the efficiency of the boiler installation.

Claims (1)

The claims A boiler plant comprising a contact air heater with a sprinkler connected by a hot air duct to the boiler furnace and a contact an economizer installed in the gas duct and a contact heat exchanger with water and gas paths, the input section of the latter of which is connected to the gas duct in front of the economizer, the fact that, in order to increase efficiency by reducing the formation of nitrogen oxides, it is equipped with a circulation fan and an additional sprinkler installed in the air heater, the latter is connected via a heating medium through an additional sprinkler to the water path of the heat exchanger with the formation of a circulation circuit, and the circulation fan is installed in the output section of the gas path of the heat exchanger, while the latter is connected to the furnace of the boiler.