RU2334167C1 - Plant for solid fuel burning - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: plant for solid fuel burning contains furnace extension and vertical furnace, which are connected via outlet screen. In furnace extension horizontal air distribution grid is installed, where fuel is exposed to partial combustion in "burning layer" of inertial material, pilot burner and device for fuel supply. In the top part of outlet screen two nozzles of secondary blowing are installed, which are directed to the bottom part of furnace. The outlet screen is formed by pipes of front screen, which is bent to the side of furnace back screen, which forms a sloping bottom with this screen and side screens. The section of front screen, which is installed above the bent part of outlet screen, is bent to the side of the furnace back screen. In the furnace extension horizontal air distribution grid is installed, on which a layer of inert material is placed, at least, one pilot burner and device for fuel supply, at that, at least, two nozzles of secondary blowing are installed in the top part of outlet screen and are directed to the bottom part of the furnace, in which bottom blowing device is installed.

EFFECT: increase of fuel burning efficiency by means of better mixing of secondary blowing air with products of fuel gasification.

1 dwg

Description

The invention relates to a power system, in particular to installations for burning low-calorie solid fuels, such as wood fuel, milled peat, hydrolysis lignin, and can be used in hot water and steam boilers.

The closest in technical essence and the achieved technical result to the claimed invention is a solid fuel combustion plant comprising a preheater and a vertical firebox framed by tubular screens and connected through a festoon formed in the tubes of the front screen of the firebox with a horizontal air distribution grill installed in the preheater, on which is located a layer of inert material, at least one kindling burner and a device for supplying fuel and at least two nozzles blast egg placed in the upper part Festoon directed to the bottom of the furnace, wherein the set of bottom blowing device (see., e.g., at RF patent №2162566 Cl. F23V 5/04 from 2000 YG).

A disadvantage of the known installation is a decrease in the efficiency of fuel combustion with a decrease in its volume due to an increase in heat loss with mechanical and chemical combustion due to a decrease in the efficiency of mixing secondary blast air with fuel gasification products coming from the pre-heating furnace to the furnace through the scallop.

The technical result, the achievement of which the claimed installation is aimed, is to increase the efficiency of fuel combustion.

To achieve the specified technical result, the proposed solid fuel combustion plant comprises a preheater and a vertical firebox framed by tubular screens and connected via a festoon formed in the tubes of the front screen of the firebox with a horizontal air distribution grill installed in the preheater, on which at least a layer of inert material is located , one kindling burner, a device for supplying fuel and at least two secondary blast nozzles located in the upper part of the festoon, e.g. located in the lower part of the furnace, in which the bottom blast device is installed, and the pre-furnace is connected to the furnace through a scallop formed in the pipes of the front screen of the furnace, bent towards the rear screen of the furnace, forming together with this screen and side screens of the furnace a cold funnel, while the front screen, located above the curved part of the festoon, is bent towards the rear screen of the furnace, and nozzles of the secondary blast are installed on the curved part of the festoon, bent towards the rear screen.

The drawing shows a diagram of an installation for burning solid fuel.

Installation for burning solid fuel contains a pre-furnace 1 and a vertical furnace 2, framed by tubular screens. The furnace 1 is connected to the furnace 2 through the festoon 3 formed in the pipes of the front screen of the furnace 2. The screens of the furnace 1 and furnace 2 are made of membrane. In the pre-furnace there is a horizontal air distribution grill 4, on which a layer of inert material 5, for example quartz sand, is located. At least one burner 6 is located in the preheater. On the side (front) part of the preheater there is a device 7 for supplying crushed solid fuel (wood waste) and silica sand. A nozzle 8 is installed in the grate for supplying primary blast air to the grate 4. At least two secondary blast nozzles 9 are placed in the upper part of the festoon 3 and directed to the lower part of the furnace. A burner 10 is located in the furnace 2. In the lower part of the furnace 2 there is installed a bottom blast device 11 with a horizontal collector 12 and a pipe 13 for draining fine particles of inert material. The upper ends of the pipes 13 are located above the collector 12. The preheater 1 is connected to the furnace 2 through a festoon 3 formed in the pipes of the front screen 14, bent towards the rear screen 15 of the furnace. Secondary blast nozzles 9 are mounted on the curved portion of the front screen festoon. These screens together with the side screens at the bottom of the furnace 2 form a cold funnel.

Installation works as follows.

Fine fuel, such as ground wood fuel, is fed through a fuel supply device 7 to a layer 5 of inert material placed on the air distribution grill 4, where it is incomplete combustion (gasification) in the "fluidized bed" mode created by the primary blast air stream. The resulting vapor-gas-like products of gasification of fuel with the entrainment of small fractions of activated wood semi-coke fall through the festoon 3 for afterburning into the furnace 2. Ignition of the products of gasification of fuel is carried out in jets of secondary blast air supplied to the furnace 2 through nozzles 9.

The supply of fuel gasification products from the preheater 1 to the furnace 2 through the scallop 3 formed in the pipes of the front screen of the furnace 2, bent towards the rear screen of the furnace 2, as well as the organization of the section of the front screen of the furnace 2 above the festoon 3, bent towards the rear screen of the furnace 2, and nozzles 9 of the secondary blast installed on the upper part of the scallop, provide effective mixing of the air jets of the secondary blast with the products of incomplete combustion of fuel from the preheater 1 and thereby increase the efficiency of fuel combustion in the installation. Secondary blast air jets pull the torch into the lower part of the furnace. Unburned particles of wood semi-coke and fine-grained sand removed from pre-furnace 1 are separated in a cold furnace funnel 2, where fine-grained sand forms a “fluidized bed” in the device 11 of the bottom blast (in tertiary blast air jets), the height of which is determined by the height of the drain pipe 13 above the collector.

Implementation example. Pre-ground wood fuel (fraction of not more than 50 × 50 × 100 mm) with a moisture content of 45% and a flow rate of 22 t / h is fed for combustion to the B-60-9.5-5-510 DFT boiler, equipped with a membrane furnace and a fluidized bed preheater. In the pre-furnace in the "fluidized bed" of an inert filler (quartz sand of a fraction of 1.0 ÷ 2.0 mm) at a temperature of 800 ° C, incomplete combustion ("gasification") of the fuel is carried out, and gas-vapor products of gasification of fuel and the entrainment of small fractions of wood semi-coke are burned up boiler furnace in jets of secondary blasting at a temperature of about 900 ° C. Particles of wood semi-coke that are not burnt in the secondary blast air jets are burned in the bottom blast devices in tertiary blast air jets. Moreover, the primary airflow rate is about 40% of the total air flow rate used for burning wood fuel at a nominal steam load of the boiler, the secondary air flow rate is about 55%, the tertiary air flow rate is about 5%.

The supply of wood fuel gasification products through the scallop formed in the pipes of the front screen, bent towards the rear screen of the furnace, in combination with the front screen section of the furnace 2 above the festoon, bent towards the rear screen of the furnace, and the installation of secondary blast nozzles on the lower part of the front screen section , bent towards the rear screen of the furnace, increase the efficiency of burning wood fuel in comparison with the installation of the prototype. The efficiency of the boiler unit both at rated and at reduced steam load is higher than on the prototype installation.

Claims (1)

Installation for burning solid fuel, containing a pre-furnace and a vertical furnace with a burner located in it, framed by tubular screens and connected through a festoon formed in the pipes of the front screen of the furnace, and a horizontal air distribution grill with a layer of inert material placed on it and at least at least one kindling burner, fuel supply device, and at least two secondary blast nozzles located in the upper part of the scallop and directed to the lower part of a PC in which a bottom blast device is installed, and the pre-furnace is connected to the furnace through a scallop formed in the pipes of the front screen of the furnace, bent towards the rear screen of the furnace, forming a cold funnel with the side screens of the furnace, and a portion of the front screen located above the curved part of the festoon , bent towards the rear screen of the furnace, and secondary blast nozzles are installed on the curved part of the festoon, also bent towards the rear screen of the furnace.