RU58674U1 - NATURAL GAS HEATER AND GAS BURNER OF THE HEATER - Google Patents

Abstract

The utility model relates to devices for heating gases or liquids and can be used in gas transportation systems in various industries, for example, gas - for heating natural gas at the inlet of gas distribution stations to prevent hydration, in addition, can be used as a generator hot water, as well as in the power system. The natural gas heater contains a gas burner 1 of an ejector type high pressure, a heat exchanger comprising a coaxially arranged gas path of combustion products made in the form of a cylindrical pipe 2 with an exhaust pipe 8, an intermediate coolant path 3, a heated gas path 4 with input 4 and output 5 collectors. A gas burner of ejector type 1 is installed at the inlet of the cylindrical pipe 2 with the formation of a gap 5 relative to the inlet section of the cylindrical pipe 2, forming a path of combustion products. The burner 1 contains a mixing chamber 9, at the inlet of which, with the formation of an annular gap, a supersonic active gas nozzle 10, sequentially located subsonic diffuser 11, cylindrical nozzles 12, in which a flame stabilizer 13 is installed, made in the form of a grid or a packet of grids. 2 n. p. f. p.m. 1 s. p. f. p .. m., 2 Fig.

Description

The utility model relates to devices for heating gas or liquid and can be used in gas transportation systems in various industries, for example, gas - for heating natural gas at the inlet of gas distribution stations in order to prevent hydration, in addition, it can be used as a generator of hot water, as well as in the power system.

Known gas supply system containing natural gas pipelines of high and low pressures, interconnected by a pipeline with a valve connected to the pressure regulator "after itself" [Handbook of the operator of gas-fired boilers, ed. E.B. Stolpner, L .: Nedra, 1988]. In this system, the natural gas pressure is reduced to the values required by the consumer by means of a pressure reducing valve. When throttling a gas, its temperature decreases, which can lead to precipitation of ice crystals and condensation of heavy hydrocarbons. This will adversely affect the reliability of the low pressure gas pipeline and the equipment installed in it (filters, valves, etc.)

A known installation for the utilization of energy of compressed natural gas, in which the heater at the gas distribution station is equipped with a furnace, the burner of which is connected to the low pressure gas pipeline with a control valve connected to a controller connected by a pulse line to a temperature sensor located in the low pressure gas pipeline, its heat exchange surface made of heat pipes, and the body is divided by a horizontal, sealed partition into two cavities, and in the lower cavity are located the zones of Spanish rhenium heat pipes, its inlet pipe is connected to the furnace, and

the output is to the chimney, while the condensation zones of the heat pipes are located in the upper cavity of the heat exchanger, which is built into the pipeline connecting the gas pipelines of high and low pressure [RF Patent No. 2079771, IPC F 17 D 1/07, publ. 05/20/97]. In this installation, the high-pressure gas is preheated by burning low-pressure gas, which is not economical.

Known heater of liquid or gaseous media (patent No. 2270406 IPC F 24 H 3/08, publ. 2006.02.20), the closest in technical essence to the claimed heater and adopted as a prototype, containing a housing with a burner device located in it, a channel for supplying air to it, a heat exchange module, including coaxially located inner and outer pipes, a burner tunnel, inlet and outlet headers, a chimney, characterized in that the heat exchange module contains at least two partitions oriented in in the opposite direction, located in the cavity between the inner and outer tubes, forming channels sequentially communicating with each other, while the cavity between the inner and outer tubes is muffled from opposite sides, the burner tunnel is placed inside the heat exchange module, and the channel for supplying air is formed by the outer heat exchange tube module and side wall of the housing. The input and output collectors are located on the side of the burner device and are connected to the channels of the heat exchange module. The partitions of the heat exchange module are provided with openings for sequential communication of channels. The heat exchange module contains an additional heat exchange element located in the cavity of the inner pipe of the heat exchange module and connecting its channels.

Known gas burners injection (ejector type) medium pressure ("Steelproject", the Basics of burning gas fuel. Isserlin AS: Nedra, 1987. p.196). Burners are typical

gas ejector with flame stabilizer in the form of a conical nozzle. Excessive active gas pressure reaches 50 kPa. The range of sustainable regulation of thermal power reaches 7. However, to fully realize this regulation range is possible only when working with a ceramic tunnel behind the burner. The ceramic tunnel has a diameter of 2 ... 2.5 times the diameter of the outlet of the flame stabilizer. Its length is 2.5 ... 3 diameters. Ceramic tunnel is a good flame stabilization device. However, it is not possible to reach speeds of combustion products of 100 m / s or more at the exit of the tunnel.

Known gas burners of the ejector type have a slight compression ratio when operating at ejection coefficients close to stoichiometric values, which completely go to overcome the resistance of the flame stabilizer. An increase in the total pressure of the active gas in excess of 0.6 atm leads to a breakdown of combustion. Due to the low total pressure of the combustible mixture and the combustion products, the velocities of the combustion products in the heat exchanger path cannot be large. The hot products of combustion are pulled through the heat exchanger using a vertical pipe, which carries out "pulling" in the heat exchanger. The speed of the combustion products in the gas path of the heat exchanger usually does not exceed 5 ... 7 m / s. As a result of the low speed of the combustion products and their low density, the heat transfer coefficients from the combustion products to the wall do not exceed 20 ... 30 W / m ² . This leads to an increase in the required heat exchange area, and ultimately to an increase in the mass and cost of the gas heater.

The burner ejection coefficient strongly depends on the back pressure in the load (for example, in the boiler); high rates of pumping combustion products through the boiler (heat exchanger) are not provided. The ejector-type gas burner combined with the tunnel nozzle is adopted as a prototype of the proposed gas burner.

The technical result, which the proposed utility model is aimed at, is to increase the efficiency of the heater, reduce its weight and cost, increase the efficiency of the burner by increasing the rate of expiration of combustion products from the burner device, as well as increasing the compression ratio with stoichiometric ejection coefficients, reducing the dependence of the ejector on the back pressure in the heat exchanger path.

The technical result is achieved by the fact that in a natural gas heater containing a burner device, a heat exchanger comprising a coaxially arranged gas path of the combustion products, an intermediate coolant path, a heated gas path, an input and output manifolds, an exhaust pipe, the burner device is new an ejector-type gas burner installed at the inlet of the gas path of the combustion products, made in the form of a cylindrical pipe, with the formation of a gap between the exit th section of the burner and the inlet section of the cylindrical tube.

The technical result is achieved by the fact that in the gas burner of an ejector type containing a mixing chamber, at the inlet of which, with the formation of an annular gap, an active gas nozzle is installed, sequentially located subsonic diffuser, cylindrical nozzles, igniter, it is new that a stabilizer is installed in the cylindrical nozzle flame made in the form of a grid or a packet of grids. The nozzle of the active gas is made supersonic.

In Fig 1. presents a diagram of a gas heater.

Figure 2 presents a diagram of an ejector burner.

Here: 1 - ejector-type gas burner; 2 - a cylindrical pipe forming a path of combustion products; 3 - the path of the intermediate coolant; 4 - a path of heated gas; 5 - the gap between the outlet section of the burner 1 and the inlet section, a cylindrical pipe 2, forming a path of combustion products; 6 - input collector; 7 - day off

collector; 8 - an exhaust pipe; 9 - mixing chamber of the burner 1; 10 - nozzle of the active gas; 1 - subsonic diffuser; 12 - cylindrical nozzles; 13 - flame stabilizer.

The natural gas heater contains a gas burner 1 of an ejector type high pressure, a heat exchanger comprising a coaxially arranged gas path of combustion products made in the form of a cylindrical pipe 2 with an exhaust pipe 8, an intermediate coolant path 3, a heated gas path 4 with input 4 and output 5 collectors. The burner 1 is installed at the inlet of the cylindrical pipe 2 with the formation of a gap 5 relative to the inlet section of the cylindrical pipe 2, forming a path of combustion products.

The burner 1 contains a mixing chamber 9, at the inlet of which, with the formation of an annular gap, a supersonic active gas nozzle 10, sequentially located subsonic diffuser 11, cylindrical nozzles 12, in which a flame stabilizer 13, made in the form of a grid or a packet of grids, an igniter ( not shown in the figure).

The heater works as follows. The active gas is supplied to the supersonic nozzle of the active gas 10. Passive atmospheric air enters the mixing chamber 9 through an annular gap. As you move along the mixing chamber 9, the gas flows are mixed, and the static pressure increases. In the subsonic diffuser 11 there is a further increase in the pressure of the mixture. The maximum pressure becomes before the stabilizer 13 - a packet of grids. The compression ratio increases with increasing total pressure of the active gas, ceteris paribus. The flow rate inside the stabilizer 13 of the grids can reach tens of meters per second. At a small distance from the grids, the flow velocity profile across the nozzle is leveled, and small-scale turbulence can still be maintained. As a result, after igniting the mixture with the pilot light behind the stabilizer 13, made in

as a grid or a grid packet, the flame front is set. The turbulent burning rate is ~ 10 m / s. The flow rate of hot combustion products is much greater, therefore, combustion processes are completed at a distance of about 2 ... 3 times the nozzle diameter after the grid. With a decrease in the active gas flow rate, the cold flow velocities along the entire path decrease, in the stabilizer 13, the flow velocities remain high at the lowest pressures of the active flow, so the flame front cannot penetrate through the grid against the flow. This is also facilitated by the active removal of heat from the flame by the mesh material, as well as by a decrease in the speed of propagation of the flame due to its lamination. With an increase in the flow rate of active gas, closed separation zones remain behind the elements of the stabilizer 13, the circulation flow in which contributes to the constant maintenance of the flame front.

When the Mach number of the cold stream behind the stabilizer 13 is 0.05, the Mach number of the hot stream at the outlet of the cylindrical nozzle 12 will be 0.17. The maximum Mach number of the cold flow behind the stabilizer 13 is 0.14. With this value, a stream with a Mach number equal to 1 appears at the output of the cylindrical nozzle 12.

Gas burner ejector type high pressure 1 provides a high speed of combustion products near the heating surfaces. The heat transfer coefficients increase with increasing gas velocity, which reduces the dimensions of the heat exchanger, ceteris paribus.

The heater is preferably located vertically. The high-pressure burner 1 is installed coaxially with a cylindrical pipe 2 forming a path of combustion products and at a certain distance from its entrance (with a gap 5 between the outlet section of the burner 1 and the inlet section of a cylindrical pipe 2 forming a path of combustion products). An intermediate coolant, such as brine, is supplied along path 3, and a heated gas passes through path 4. Pumping speed increase

the hot flow several times, almost the same amount of time increases the generalized heat transfer coefficient, and, as a result, the mass and dimensions of the heater as a whole are reduced.

In high pressure ejector type gas burners, the amplitude of acoustic vibrations is substantially less than the excess pressure created by it. The complete disappearance of acoustic vibrations at resonant and multiple frequencies can be achieved by introducing a gasdynamic isolation into the system - by placing a cut of burner 1 at a distance from the entrance to the cylindrical pipe 2, while burner 1 emits only noise associated with turbulent combustion. The prevention of acoustic vibrations increases combustion stability and reduces noise levels.

Claims (3)

1. A natural gas heater comprising a burner device, a heat exchanger comprising a coaxially arranged gas path of the combustion products, an intermediate coolant path, a heated gas path, characterized in that the burner device is an ejector type gas burner installed at the inlet of the gas path of the combustion products in the form of a cylindrical pipe with the formation of a gap between the outlet section of the burner and the inlet section of the cylindrical pipe. 2. A gas burner of a heater containing a sequentially located mixing chamber, at the inlet of which, with the formation of an annular gap, an active gas nozzle, a subsonic diffuser, a cylindrical nozzle, an igniter are installed, characterized in that a flame stabilizer made in the form of a grid is installed in the cylindrical nozzle or a packet of grids. 3. The gas burner according to claim 2, characterized in that the active gas nozzle is made supersonic.