JPS5952103A - Economizer in which adhesion of dust is reduced - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a one-digit energy saver for a boiler, and particularly to a energy saver that can be suitably implemented in a boiler that burns black liquor produced in a pulp manufacturing process.

Like other heat exchangers, the energy saver that heats the boiler feed water by exchanging heat between the combustion exhaust gas generated in the boiler furnace and the boiler feed water is required to keep its heat transfer coefficient high. It is necessary to prevent dust in the exhaust gas from adhering to the exhaust gas.

In particular, in black liquor recovery boilers that burn the waste liquid called black liquor generated in the pulp manufacturing process to recover the chemicals and heat contained in it, mirabilite (Na2So4) is contained in the exhaust gas.
Since many of the ends contain highly adhesive dust such as, there is a need for countermeasures against this problem.

Figure 1 shows this black liquor recovery boiler. In the figure, l indicates a black liquor recovery boiler, which injects black liquor generated in the pulping process from an oscillator 2 toward the opposing furnace wall.
Dry on this furnace wall. The dried solids (char) fall to the bottom of the furnace to form a charbet 3, and combustion takes place in this charbet 3. This combustion causes
The contained chemicals are discharged from the smelt spout 4 to the outside as a molten smelt and collected. On the other hand, the combustion exhaust gas rises through the furnace 5 to the slag screen 6 and superheater 7. It reaches the energy saver 9 via the evaporator 8. A plurality of baffles 10 are attached to the economizer 9 so as to be substantially perpendicular to the tube bodies (heat transfer tubes) constituting the economizer.

This causes the exhaust gas G to meander along the baffle 10,
Flows almost perpendicular to the heat exchanger tubes. In the case of this type of economizer, the exhaust gas G and the heat exchanger tubes flow almost perpendicularly to each other, so dust tends to adhere to the heat exchanger tubes.Furthermore, there are many flow path change parts for the exhaust gas, so the flow Dust accumulates mainly around the road change section. Therefore, it is necessary to install a large number of soot blowers 13 to remove dust, and if steam is used as the injection medium, a considerable amount of steam generated in the boiler will be consumed, which is uneconomical. Furthermore, when the exhaust gas flows out to the exhaust gas outlet 11 side, the dust in the exhaust gas falls into the hopper 12 due to inertia and is collected. It wasn't too expensive either.

SUMMARY OF THE INVENTION The object of the present invention is to provide an economizer that eliminates the two problems and reduces dust build-up.

In short, the present invention is an economizer in which a baffle is provided so as to be substantially parallel to the heat transfer tubes constituting the economizer, so that the exhaust gas flows approximately parallel to the group of heat transfer tubes.

Embodiments of the invention will be described below with reference to the drawings.

In FIG. 2, fff constitutes a part of the boiler main body 1.
j Three sets of heat transfer tube groups 15 a, 15 b, and 15 c forming a coal economizer 15 are arranged in the coal burner installation passage 14. Reference numerals 16a and 16b are baffles formed substantially parallel to the heat exchanger tube arrangement direction so as to partially partition these heat exchanger tube groups. 17 is a hopper formed under the heat exchanger tube groups 15a and 15b, and 18 is a hopper formed under the heat exchanger tube group 15c. Note that a baffle 16c may also be formed between the evaporator tube 8 and the heat exchanger tube group 15a to adjust the flow of exhaust gas flowing into the heat exchanger tube group 15a. In this device, the exhaust gas G that has passed through the evaporator tube 8 is transferred to the first heat exchanger tube group 15.
a, and descends along this heat transfer tube group 15a to reach the hopper 1.
At step 7, it is reversed and removed in parallel to the second heat exchanger tube 1jr15b. During this reversal and rise, the dust in the exhaust gas falls toward the hopper 17 due to inertia and is discharged to the outside. The exhaust gas G that has removed the second heat exchanger tube group 15b turns around again and descends through the third heat exchanger tube group 15c, and exits the exhaust gas (
” 11 and is discharged to the outside. During this time, the dust in the exhaust gas G falls into the pot 18 and is discharged out of the system. The soot blower 13 is a soot blower, but since the exhaust gas G is passed through the heat transfer tube and flows in parallel, there is almost no dust attached except for the exhaust gas flow path change portion. For this reason, the soot blower is installed at two locations for each heat exchanger tube group, one at the upper end and the other at the upper end. Furthermore, the dust removed by the soot blower on the upper end side descends to hopper 17 or 18 by the exhaust gas flow, and the dust removed by the soot blower on the lower end side falls directly into these hoppers and is removed.

By carrying out this invention, the exhaust gas flows parallel to the heat exchanger tubes constituting the economizer, so that the dust (=i, I) on the surface of the heat exchanger tubes is significantly reduced, and high heat transfer efficiency can be maintained at all times. It is economical because the number of installed soot blowers can be reduced.

In addition, the dust mainly consisting of Glauber's salt can be well collected, the burden on the subsequent dust collector can be reduced, and the utilization rate of Glauber's salt can also be increased.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a black liquor recovery boiler that uses a conventional coal saver, and FIG. 2 is a cross-sectional view of a Mj coal boiler related to this IJ. 1...Boiler body 13...Soot blower 14...Coal economizer installation passage 15...Coal economizer

Claims (1)

[Claims] 1. In an arrangement in which a group of heat transfer tubes for heating supply water is arranged in an exhaust gas flow path, the group of heat transfer tubes is divided into a plurality of groups, and these groups of heat transfer tubes are placed between each group of heat transfer tubes. 1. An energy saver that reduces dust adhesion, characterized in that a baffle is provided in parallel with the heat exchanger tubes, so that exhaust gas flows parallel to each group of heat exchanger tubes. 2. The energy saving device that reduces the amount of dust deposited as claimed in claim 1, characterized in that a dust removal hopper is disposed at the lower end of each heat exchanger tube group.