JPS5834756B2 - Under-grate air blast supply equipment for gas generators - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a gas generating furnace, and more particularly to a grate structure blast supply device for a coal gas generating furnace.

Conventional gas generators generally consist of an elongated cylindrical refractory structure, with a coal feeding device and a gas extraction device in the upper part, and an annular trough filled with water in the lower part. It has a metal seal skirt depending into the trough.

This trough acts as a seal to prevent gases produced within the generator from escaping from the furnace, and also serves as an ash collection zone.

Above the area defined by the annular inner wall of this trough, a usually conical grate structure is installed and below this grate is called the grate structure blast supply pipe. A conduit assembly is arranged.

This conduit supplies steam-saturated air through the grate and into the gas generator.

The trough and grate assembly is rotated to smoothly remove ash from the generator.

Therefore, it is necessary to provide a seal between the stationary, stationary grate structure plastic supply tube and the rotating grate assembly.

Conventional devices for delivering air to the generator furnace have various drawbacks, as discussed below.

The aim of the invention is to suppress some of these disadvantages at least as far as possible.

The traditional method of introducing all of the air required for coal combustion through the grate is extremely inefficient.

This is because the cross-sectional area of the grate is only 4% of the total cross-sectional area of the grate.
This is because it only occupies the 0 section.

For this reason, the amount of air per unit area of the fire bed gradually decreases as you move outward in the radial direction of the fire bed, as the highest concentration of air is supplied to the center where the fire bed area is smallest. be.

This not only results in non-uniform operating conditions of the grate and therefore non-uniform treatment of the coal in the generator;
The highest temperature of the grate will occur in its center, causing clinker to form there.

In order to obtain the ideal operation of a gas generator, the air flow should be uniform over the entire surface of the grate, thereby reducing the temperature in the center of the grate and reducing the temperature of the coals above the grate. uniform conditions for gasification should be provided for all of the

The feature of the gas generating furnace of the present invention is that the air supplied to the generating furnace is
A conduit system is provided that divides into a first air flow that feeds into the generator furnace through the central grate assembly and a second air flow that feeds into the furnace through the side walls of the furnace at approximately the same height as the grate assembly. That's true.

Preferably, the conduit system is provided with a manifold consisting of an annular tube extending around the outer wall of the gas generator and having an inlet tube and a plurality of air outlet tubes passing through the generator wall.

It is also preferable to balance the amount of air supplied to the under-grate air blast tube with the amount of air supplied to the manifold structure.

Therefore, it is preferable that the under-grate air blast pipe and the manifold are branched from a common air supply pipe, and that an air flow balancing damper controller is provided downstream of the branch point.

The invention thus makes it possible to blow air from the outer periphery of the grate into an area called broadband, which occupies a large area within the grate.

The total amount of air supplied is the same as in a conventional under-grate air blast tube, but the amount of air supplied under the grate is less.

Therefore, the temperature in the center of the grate is reduced considerably,
It allows the use of a wider range of fuel types than was possible with conventional devices, especially when ash melting temperatures have to be taken into account.

Since the coal residue to be gasified is treated uniformly, the quality of the gas generated is excellent and the control of the operation of the generating furnace is simplified.

Furthermore, the even combustion of the grate reduces or eliminates the amount of unburned fuel that is removed from the generator along with the ash.

Air flow deflectors are provided within the grate carrier near the entrance to the grate assembly to improve air distribution through the grate.

This deflection member can be constituted by a conical member with its apex directed upstream.

It is necessary to provide a rotating seal in the gas generator between the rotating grate and the stationary under-grate air blast tube.

Conventional seals are by water seals deep enough to seal the air pressure below the grate from the atmosphere.

Mechanical seals are inadequate because they do not provide close tolerances to accommodate irregular rotational movement of the grate.

Of course, the depth of the water seal must be greater than the pressure of the air blast under the grate.

This creates the problem that either a pit must be formed under the furnace to accommodate the seal, or the furnace must be raised to the height of the seal.

This problem is exacerbated by the fact that the higher the pressure of the gas produced, the greater the depth of the water seal must be proportionally increased.

For example, the pressure at the gas outlet of the generating furnace can be measured at 30 i using a water column meter.
n (762 mm), the air pressure under the grate must be 60 iH (1524 mm) on the water column gauge, thus requiring a water seal approximately 66 inches (1676 mm) deep.

According to another feature of the invention, the seal between the grate and the under-grate air plast tube is provided by a cylindrical skirt fixed around and depending from the inlet to the grate carrier; an annular trough filled with mercury carried on the upper end of the under-grate air blast tube, with the lower portion of the skirt projecting into the mercury of the trough.

To prevent the mercury from oxidizing, a layer of oil is placed on top of the mercury.

Another problem associated with gas generators is that resulting from interruptions in operation due to mechanical failure or power outages.

In the event of such an interruption, a purging operation of the furnace must be performed before the generator can be restarted.

In order to prevent outside air from entering the furnace from anywhere, the inside of the furnace must be kept under positive pressure at all times. requires a purge operation.

For example, if an electrostatic precipitator is installed in a gas generation plant that performs hot tar removal operations or cold cleaning operations, a purge operation is particularly necessary.

Although the purge operation is time-consuming and troublesome, it is essential because there is a risk of explosion if the inside of the generating furnace becomes negative pressure.

According to a further feature of the invention, the under-grate air supply device is equipped with an emergency fan operated by an independent power source.

This fan is automatically activated when the pressure within the generator furnace drops below a predetermined minimum positive pressure limit to maintain a constant positive pressure within the furnace.

For example, if the main air blast fan stops operating for any reason, a small engine-driven fan with a battery operated electric starter can be immediately attached to the main air blast conduit.

Or alternatively, instead of an engine-driven fan,
It may be operated by a battery maintained by a trickle charger, or a C-motor driven fan may be provided so that the fan is operated for a predetermined period of time.

The function of this fan is to maintain a low but constant positive pressure inside the gas generator when the main fan stops for any reason, thereby ensuring that there is no delay after the failure or power outage is resolved. Gas generation operations can be resumed immediately without the need to purge the equipment.

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

With reference to the attached figures, there is shown a lower part of a gas generator with side walls made of refractory material.

The lower part of the side wall constitutes a water jacket 1 and a seal skirt 2.

Seal skirt 2 is an annular trough filled with water.
It hangs down inside 3.

A platform (support plate) 4 is provided nearby so as to cover the space defined by the inner wall 3a of the trough 3, and a grate carrier 5 is mounted on the platform 4.

A conical grate 6 is mounted on this grate carrier.

A large number of holes 6a are formed in the grate 6.

The trough 3 and grate assembly 56 are adapted to rotate on bearings 7 in a known manner.

Steam saturated air is fed into the generator by two paths.

For this purpose, the main air supply pipe 8 is divided into an under-grate air supply pipe 9 and a broadband air supply pipe 10.

Arranged in the grate carrier 5 below the grate 6 is an air flow deflector 11 for evenly distributing the air passing through the grate.

The deflection member 11 is formed by stacking two cones back to back.

The seal between the rotating grate assembly and the stationary under-grate air blast tube 18 is provided by a depending skirt 12 fixed around an air inlet opening drilled in the platform 4 and an air It consists of an annular trough 13 fixed to the upper end of the blast tube 18 and filled with mercury (not shown), with the lower part of the skirt 12 projecting into the mercury of the trough.

To prevent the mercury from oxidizing, a layer of oil is placed on top of the mercury before the button is pressed.

The above-mentioned under-grate air supply piping system enables uniform air distribution through the grate and provides effective sealing,
It also has the advantage of providing a seal that can accommodate some degree of irregular (out-of-round) movement of the rotating grate assembly.

The use of mercury rather than water as the sealing medium allows the seal height to be relatively low.

A broadband air supply pipe 10 exhausts air into a manifold structure 14 from an annular pipe 15 extending around the generator.

The annular pipe 15 is equipped with a plurality of air jetting pipes 16, and jets air into the generation zone through holes 16a formed in the side wall of the generating furnace.

The holes 16a for receiving each jet pipe 16 are arranged at approximately the same height as the lower holes 6a of the grate 6.

A damper controller 17 is arranged in each of the air supply pipes 9, 10, so that they can be adjusted to equalize the distribution of air through the grate.

As previously mentioned, the fixed under-grate air blast tube 18
The top end is equipped with a mercury seal 12.13.

The tube 18 is open at both its upper and lower ends, and the tip of the air supply tube 9 is connected to a region 23 between both ends of the tube 18 with a button.

The ash falling through the grate 6 into the air blast tube 18 can be removed from the lower end of the tube 18 by a screw conveyor.

This ash removal device is described in the applicant's Japanese patent application entitled ``Apparatus for removing ash from an under-grate air-plast tube,'' filed on the same day as the present application.

The previously mentioned emergency fan (not shown) can be arranged to direct air into the main air supply pipe 8 upstream of the junction of pipes 9 and 10.

Although the present invention has been described in detail above, it will be appreciated by those skilled in the art that the present invention is not limited thereto, and that various changes and modifications can be made without departing from the spirit and scope of the present invention. should be obvious.

[Brief explanation of drawings]

The accompanying drawings are longitudinal sectional views showing one embodiment of the present invention. In the figure, 5 is a grate carrier, 6 is a grate, 8 is a main air supply pipe, 9 is an air supply pipe under the grate, 10 is a broadband air supply pipe, 11 is an air flow deflection member, 12 is a hanging skirt, 13
14 is a trough, 14 is a manifold, 15 is an annular pipe, 16 is an ejection pipe, 17 is a Dunno IJ# device, and 18 is an air blast pipe under the grate.

Claims (1)

[Claims] 1. In a gas generator, a first air stream for supplying air to the generator into the generator through a central grate assembly and a side wall of the generator at approximately the same height as the grate assembly. A gas generating furnace characterized in that it is equipped with an air supply pipe system that divides the air into a second air flow and a second air flow that is supplied into the generating furnace through a portion of the gas generating furnace.