SU1746114A1 - Method of heat reception control for boiler evaporating surface - Google Patents

Abstract

Usage: regulation of heat output of boilers operating in the regulation range of loads when burning a mixture of several types of fuel, including solid fuel. Summary of the invention: the total heat of combustion of the mixture of fuels is kept constant in accordance with a given heat load of the boiler, and the heat of the evaporative heating surface of the boiler is controlled by changing the radiation component of the heat flux by changing the fraction of heat generated by solid fuel in the furnace.

Description

The invention relates to a power system, and more specifically to methods for controlling the heat pickup of evaporative heating surfaces of a boiler when a mixture of fuels (solid and gaseous, solid and liquid, as well as their mixtures) is burned in a furnace.

There is a known method of controlling the heat perception of the evaporation surface to heat the boiler operating in the sliding pressure mode by changing the temperature of the feed water at the inlet to the evaporation heating surface by changing the steam consumption in the heating unit 1.

Closest to the invention is a method for controlling the heat gain of an evaporating surface by adjusting the flow rates of the fuel mixture in accordance with a predetermined heat load 2.

A disadvantage of the known methods is to reduce the efficiency of the unit while reducing the steam consumption to the heater, as well as reliability, if it is necessary to increase the heat gain of the evaporative heating surface.

The purpose of the invention is to increase reliability.

The goal is achieved by changing the heat of the evaporative heating surface of the boiler by changing the proportion of the heat of the combustible solid fuel released in the furnace at a constant value of the heat of the mixture of fuels,

The essential difference of the invention is that. what's in the adjusting diapd2

Os

Not the load of the boiler, the change in the heat perception of the radiation heating surfaces is made by changing the amount of the radiation component emitted in the furnace heat of the combustible mixture of fuels due to the change in the amount of solid fuel fed to the furnace. At the same time, the total heat released during the combustion of a mixture of fuels remains unchanged, 0Cum const.

The method is carried out as follows.

Let three types of fuel be burnt in the boiler furnace: solid (coal dust), liquid (fuel oil), and gaseous (natural gas) in appropriate proportions, i.e. total heat released in the furnace by three types of fuel

Osum Q + Aug + Or,

where Q, Od, Qr is the amount of heat, which is allocated during combustion, respectively, of solid, liquid and gaseous fuels.

Regulation of heat output is as follows.

If it is necessary to increase the heat perception of the evaporative heating surface, the amount of heat generated by burning solid fuels should be increased, and consequently, the proportion of the radiation component in the total heat of the fuel should be increased, while the amount of heat due to burning gas and fuel oil should be reduced. And Q CU + Qr. Increasing the proportion of heat generated during the combustion of solid fuel increases the radiation component of the total heat, and consequently, increases the heat emission of the evaporative heating surface, and vice versa, increasing the proportion of heat during the combustion of gaseous or liquid fuel decreases the radiation component of the total heat that results to a decrease in heat absorption of the evaporative heating surface.

When burning two types of fuel (solid and liquid or solid and gaseous), heat control is controlled

The evaporative heating surface of the boiler is made similarly.

The implementation of the method on the example of the boiler TPE-208.

In the furnace of the boiler TPE-208 unit 200 MW

brown coal near Moscow and natural gas are burned. When burning brown coal and natural gas in the furnace near Moscow in proportions of 30 and 70%, respectively, the temperature of the metal of the screen tube in the furnace (by inset) was 420 ° C. With an increase in the proportion of coal burned (by heat) to 40%, and a decrease in natural gas to 60%, the temperature of the metal of the screen pipe increased by 9 ° C and amounted to 429 ° C. At the same time, the temperature of the medium heated in the pipe increased, and, consequently, the heat gain. Reducing the amount of coal burned to 30% and increasing the amount of gas burned to 70% of heat, i.e. restoring the mode, the temperature of the metal of the screen tube decreased to the previous value of -420 ° C.

Thus, by changing the amount of coal dust burned in the furnace, and therefore the radiation component of the heat released in the boiler’s furnace, while maintaining the total amount of heat released in the furnace

By increasing or decreasing the supply of other types of fuel (gaseous or liquid), the temperature of the metal in the evaporative heating surface changes, and hence its heat absorption.

Claims (1)

Claims of the Invention The method of controlling the heat efficiency of an evaporative heating surface of a boiler operating in the control range of loads when burning a mixture of fuels, including solids, by maintaining the total heat of combustion of fuels in accordance with a given heat load and heat dissipation fuels, in order to increase reliability, change the flow of all types of fuel mixture, correcting the proportion of heat released in the furnace when solid fuel is burned while maintaining a constant total heat of combustion of the fuel mixture.