RU2733566C1 - Burner device for heating of gaseous flow - Google Patents

Abstract

FIELD: power engineering.

SUBSTANCE: invention relates to the field of power engineering. Burner device for heating of gaseous flow is located in channel, at that in device is uniformly installed many burner modules divided into peripheral and near-center burners, where to each module along separate main line fuel is supplied from at least one collector. At the inlet to each separate main line there is an adjusting jet limiting the fuel flow, and lines for peripheral and near-center burners are made with different degree of heat exchange of fuel with gaseous flow depending on removal of burner modules from channel walls and ratio of fuel and gaseous flow temperatures. Detachable block-heat exchanger is installed at collector inlet. Detachable block-heat exchanger installed at collector inlet is made in form of fuel heater. Detachable block-heat exchanger installed at collector inlet is made in form of fuel cooler.

EFFECT: invention makes it possible to take into account non-uniformity of the flow temperature field at the inlet of the burner device, possibility of adjusting the uniformity of temperature fields and to reduce the temperature gradient of the channel walls.

4 cl, 4 dwg

Description

The invention relates to the field of heat power engineering and gas turbine construction, in particular to burners for heating, for example, air, in front of various kinds of heat exchangers in technological production processes, or for heating exhaust gases from gas turbine plants before they are fed to the waste heat boiler of a combined cycle plant.

Some of the main requirements for such burner devices are the following:

- uniformity of temperature fields in the cross-section of the heated flow downstream of the burner device, since the more uniform the temperature fields in front of the heat exchanger or waste heat boiler, the higher their efficiency;

- ensuring the minimum temperature gradients along the channel walls from the burner device to the heat exchanger to prevent overheating and burnout of the walls.

In addition to the fact that these requirements are quite difficult to fulfill in themselves, they also contradict each other, because to avoid overheating of the walls, it is necessary to reduce the temperature of the peripheral (near-wall) layers of the flow, while the required average temperature of the flow is ensured by additional heating of its near-central regions. , which inevitably worsens the uniformity of temperature fields.

It is known from the theory of combustion that the combustion rate has an exponential dependence on the temperature of the mixture of fuel and oxidizer, "Fundamentals of the theory of combustion", textbook, A.V. Talents -

Kazan Aviation Institute, 1975. In addition, it is known that the length of the combustion torch behind any burner is inversely proportional to the combustion rate, i.e., the colder the mixture of fuel and oxidizer, the longer over a longer length and more sluggishly the process of fuel burnout will proceed, on the contrary, the hotter the mixture, the more intensive, faster and at a shorter length the mixture will burn out. It is also known that the final temperature of the combustion products behind the burner module does not depend on the combustion rate, but depends on the initial temperature of the mixture and the concentration of fuel in the oxidizer.

As follows from numerous studies of combustion processes, the uniformity of the temperature fields behind the burner, other things being equal, depends on the uniformity of the fuel concentration in the cross section ahead of the combustion front and the uniformity of the temperature field at the inlet to the burner. However, the temperature field at the inlet to the burner is usually not uniform, especially when it comes to the gas turbine exhaust flow field, where the temperature unevenness at the outlet of the gas turbine nozzle can reach 200 ° C or more. In addition to the temperature unevenness, the uneven concentration of the oxidizer (oxygen) is pronounced in the exhaust gases, which, taking into account the individual characteristics of each gas turbine, requires appropriate - individual measures to obtain an even temperature field.

Known burner device for heating exhaust gases of gas turbines (SU No. 694652, IPC F02K 3/10, publ. 10/30/1979), containing a grid of flame stabilizers, each of which is equipped with a fuel supply channel containing a fuel distributing tube, and the fuel holes in the fuel distributing tube and are misaligned in the fuel channel.

The disadvantages of this device are the inability to take into account the unevenness of the flow temperature field at the inlet to the burner

device for adjusting a uniform field at the outlet of the burner, the inability to adjust the uniformity of the temperature field along the stabilizer, low reliability due to high temperature gradients of the channel walls due to the coincidence of the planes of maximum heat release of the combustion torches.

Known burner device for heating exhaust gases of gas turbines according to the patent (RU No. 153431, F02K 3/10, F23D 14/74, publ. 20.07.2015), the closest in technical essence and taken as a prototype, located in the channel, while in In the device, a plurality of burner modules are evenly installed, divided into peripheral and central burners, where fuel from at least one collector is supplied to each module via a separate line.

The disadvantages of this device are the inability to take into account the unevenness of the flow temperature field at the inlet to the burner device, the inability to adjust the uniformity of the temperature field along the stabilizer, low reliability due to high temperature gradients of the channel walls due to the coincidence of the planes of maximum heat release from the combustion torches.

The technical problem, the solution of which is provided in the implementation of the proposed invention and cannot be realized when using the prototype, is the inability to take into account the unevenness of the flow temperature field at the inlet to the burner device, the inability to adjust the uniformity of temperature fields in the direction along the stabilizers, low reliability of the channel walls due to due to high temperature gradients along the channel walls due to the coincidence of the planes of maximum heat release from fire torches.

The technical objective of the present invention is to ensure the possibility of taking into account the unevenness of the flow temperature field at the inlet to the burner device, ensuring the possibility of adjusting the uniformity of temperature fields both vertically and horizontally.

the directions of the cross-section at the outlet of the burner and a decrease in the temperature gradient of the channel walls and an increase in its reliability without deteriorating the unevenness of the temperature fields.

The technical problem is solved by the fact that in the burner device for heating the gaseous flow located in the channel, a plurality of burner modules are evenly installed, divided into peripheral and central burners, where fuel is supplied to each module via a separate line from at least one manifold, according to the invention, on an adjustable nozzle limiting the fuel consumption is installed at the entrance to each separate line, and the lines for the peripheral and central burners are made with different possible degrees of heat exchange between the fuel and the gaseous flow, depending on the distance of the burner modules from the channel walls and the temperature ratio between the fuel and the gaseous flow.

In addition, according to the invention, a removable unit - a heat exchanger is installed at the inlet to the collector.

In addition, according to the invention, a removable unit - a heat exchanger installed at the collector inlet - is made in the form of a fuel heater.

In addition, according to the invention, a removable unit installed at the collector inlet - a heat exchanger is made in the form of a fuel cooler.

In the proposed invention, in contrast to the prototype, the installation in each separate line of an adjustable jet allows you to regulate the fuel consumption in the course of each line, which in general allows you to regulate the temperature fields at the outlet of the burner, including taking into account the temperature fields at the entrance to burner device.

Execution of pipelines for peripheral and near-center burners with different degrees of heat exchange of fuel with a gaseous stream, in

depending on the distance of the burner modules from the channel walls and the ratio of the temperatures of the fuel and gaseous flow, it allows to reduce temperature gradients along the channel walls and increase its reliability without deteriorating the unevenness of the temperature field.

The implementation of a removable block at the inlet to the manifold allows you to adjust the fuel temperature to distinguish it from the temperature of the gaseous stream.

FIG. 1 - shows the options for the burner device in channels of different cross-sectional shape, rectangular - "a" and round "b".

FIG. 2 - shows a section of the burner along the horizontal x axis.

FIG. 3 - shows a removable block at the entrance to the manifold of the burner.

FIG. 4 - shows the operation of the burner with the planes of maximum heat release in the rows of burner modules.

Burner device 1 for heating the gaseous flow, located in a channel, for example, rectangular or circular (Fig. 1) cross-section, while the device evenly installed a plurality of burner modules 2 of different shapes and divided into peripheral 7 and near-center 8 burners, where to each module 2 through a separate line 4, fuel is supplied from at least one collector 3. At the inlet to the collector, a removable unit can be installed - a heat exchanger 6, made in the form of a fuel heater or fuel cooler. A heater or fuel cooler is installed when the fuel and air temperatures are close in value. At the entrance to each separate line 4, an adjustable nozzle 5 is installed that limits fuel consumption, and lines 4 for peripheral 7 and near-center 8 burners are made with a different degree of heat exchange of fuel with a gaseous stream, depending on the removal of burners

modules 2 from the walls of the channel 9 and the ratio of the temperatures of the fuel and the gaseous flow.

The burner works as follows.

For the case when the temperature of the heated gas flow is higher than the fuel temperature - this is a typical case when heating the exhaust gases of gas turbines with a temperature of 350 ... 450 ° C, at a fuel temperature of 10 ... 50 ° C, the fuel supply lines to the peripheral burner modules are short to reduce the degree of fuel heating by a stream of heated gas, and can also be thermally insulated, to almost completely eliminate heating. The lines of the central burner modules are made of different lengths, the farther from the channel walls, the longer the line, respectively, the higher the degree of fuel heating, and the lines can be finned for the highest degree of heating.

For the case when the fuel temperature is higher than the temperature of the heated flow, the lines of the peripheral modules of the burners are made more authentic and can be finned to increase the degree of fuel cooling, and the lines of the center modules are of different lengths with different degrees of thermal insulation, see Fig. 4, the part right relative to the axis.

For the case when the temperature of the fuel and the heated gas flow are approximately equal, a removable unit is installed at the inlet to the manifold of the burner device - a heat exchanger, in which the fuel is heated, for example, by hot gases taken out after the burner device, and the fuel supply lines to the modules are performed in accordance with the case when the temperature of the heated gas stream is higher than the temperature of the fuel. Or, a removable unit is installed - a heat exchanger, in which the fuel is cooled, for example, by water taken from the heat recovery boiler before the boiler, and the fuel supply lines are performed in accordance with the case when the temperature of the heated

gas flow above the fuel temperature. The energy transferred to the fuel in the removable unit - the heat exchanger is returned to the installation cycle and therefore is not lost.

Adjustment of temperature fields at the entrance to each separate line of the burner device is carried out by adjusting the fuel consumption with adjustable nozzles at the entrance to each line.

Thus, the supply of low-temperature fuel to the peripheral modules is ensured and the temperature of the fuel increases from row to row of modules in the direction from the periphery to the center of the burner. As a result, the relatively sluggish combustion behind the peripheral burners in the immediate vicinity of the channel walls will provide a sparing thermal mode of operation for the latter, and the increasing intensity of fuel burnout from row to row of burner modules will ensure the separation along the channel axis of the planes of maximum heat release of combustion torches, which also contributes to a decrease in thermal channel wall gradients and increasing its reliability.

Claims (4)

1. A burner device for heating a gaseous flow located in a channel, while a plurality of burner modules are evenly installed in the device, divided into peripheral and central burners, where fuel is supplied to each module through a separate line from at least one manifold, characterized in that on an adjustable nozzle limiting the fuel consumption is installed at the entrance to each separate line, and the lines for the peripheral and central burners are made with different degrees of heat exchange between the fuel and the gaseous flow, depending on the distance of the burner modules from the channel walls and the temperature ratio between the fuel and the gaseous flow. 2. The burner device according to claim 1, characterized in that a removable unit - a heat exchanger is installed at the inlet to the manifold. 3. The burner device according to claim 1, characterized in that the removable unit - heat exchanger installed at the collector inlet is made in the form of a fuel heater. 4. The burner device according to claim 1, characterized in that the removable unit - the heat exchanger installed at the collector inlet - is made in the form of a fuel cooler.

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