JPS62124211A - Lance for refining and combustion - Google Patents

Abstract

PURPOSE:To improve the durability of the titled lance of a reaction vessel for metal refining and to simplify the construction thereof by providing lining of a ceramic refractory material to a nozzle for pneumatic feeding of a carbonaceous powder material into said lance. CONSTITUTION:The lance for combustion for making the contact of the pneumatic feed flow of the carbonaceous powder material (expressed as C) and gaseous O2 flow enclosing the same toward the charge in the reaction vessel for metal refining has a flow passage 1 for the material C. An inert gas or nonoxidative gas which hardly reacts with the carbon in the material C is usually used as a carrier gas in order to avert the combustion or explosion in a piping 3 including the passage 1 to lead the pneumatic feed blow. The lining 2 consisting of the ceramic refractory material having excellent heat and wear resistance is provided to the flow passage 1 so that said flow passage is protected against the wear and frictional heat by the contact with the material C or the high-temp. atmosphere in the reaction vessel. Perforation of the lining 2 is detected if a thermocouple 4 for measuring the temp. of a mouthpiece 5 which is the ejection port for the material C of the flow passage 1 is provided to face the rear surface of the lining 2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The use of carbonaceous powder materials to compensate for the heat source of blowing in metal refining reaction vessels, such as bottom blowing converters or similar refining and refining. Although flame projection onto the vessel contents by contact within the reaction vessel between a pneumatic feed stream and a surrounding oxygen gas stream is useful, in connection with such combustion lances, this specification includes: The results of research and development aimed at improving the durability of the lance while simplifying the structure will be described below.

(Prior art) Regarding a refining/combustion lance in a reaction vessel for metal refining, Japanese Patent Application Laid-Open No. 144409/1983 states that carbon fine powder as a carbonaceous powder substance is transported from the center passage of the lance, and oxygen gas is transported from the surrounding area. Although it has been disclosed that the cooling fluid is injected from each passage, it requires a cooling fluid passage surrounding the central passage, which results in a complicated structure and poor durability.

(Problem to be Solved by the Invention) The charge in a reaction vessel for metal refining is exposed to flame by contact between a pneumatic feed stream of carbonaceous powder material and an oxygen stream surrounding it. The purpose of this invention is to improve the durability of a combustion lance used to assist in the refining of raw materials by simplifying the structure, and by achieving this, it is possible to facilitate operations by reducing the frequency of lance replacement. This is intended to contribute to improving production efficiency.

(Means for Solving the Problems) The present invention provides a pneumatic supply flow of carbonaceous powder material and an oxygen gas flow surrounding the pneumatic supply flow from above a reaction vessel for metal refining toward a charge in the reaction vessel. A combustion lance for smelting and combustion, characterized in that the nozzle that controls the pneumatic supply of carbonaceous powder material has a lining of a heat-resistant and abrasion-resistant ceramic refractory material. It's Lance.

The inventors studied various materials and structures for the injection channel for carbonaceous powder in the lance, and found that the nozzle of the channel has a lining made of a ceramic refractory material with excellent heat resistance and wear resistance. As a result, we have found the following advantages:

(1) Nozzle cooling is not required and the lance structure can be simplified; (2) nozzle wear resistance is improved and lance durability is improved; It is also possible to detect wear and tear by installing a thermocouple that is useful for detecting wear and tear.

Now, FIG. 1 shows a cross section of a refining/combustion lance according to the present invention.

In the figure, 1 is a flow path for carbonaceous powder material, and in order to avoid combustion or explosion in the piping including this flow path 1, reaction with inert gas or carbon in the material is normally avoided. (Directing a pneumatic feed stream with a non-oxidizing gas as the carrier gas.

2 is a lining made of a ceramic refractory material with excellent heat resistance and abrasion resistance, which is provided to protect the flow path 1 of the carbonaceous powder material from abrasion and frictional heat caused by contact with the substance or the high temperature atmosphere in the reaction vessel. It is. The ceramic refractory materials include BC and WC.

TtC, A I ZO1+ Zr0z, 5fOz+
Use sic etc.

Reference numeral 3 indicates a flow path piping for the carbonaceous powder material, and since the outer peripheral surface is in contact with oxygen gas, a stainless steel pipe or a steel pipe that can withstand even an oxidizing atmosphere is used.

Reference numeral 4 denotes a thermocouple that measures the temperature of the mouthpiece 5 that serves as the spout of the carbonaceous powder material from the flow path 1, and the lead wire of this thermocouple is exposed when a hole is formed in the lining 2 due to wear. This can be used to detect holes in the lining, quickly detect abnormalities in the lance, and prevent damage to the lance and major accidents. Note that the thermocouple 4 is wound around the outer peripheral surface of the lining 2 or installed along the longitudinal direction of the lining 2 to ensure good contact between the tip 4' of the thermocouple 4 and the mouthpiece 5, and to maintain the temperature of the mouthpiece 5. Measure accurately.

The lining 2, flow path piping 3, and mouthpiece 5 constitute a nozzle 6 that controls pneumatic supply of carbonaceous powder material.

Furthermore, since the mouthpiece 5 is located at the tip of the nozzle 6 and is exposed to the highest temperature and oxidizing atmosphere, it is made of heat-resistant, non-oxidizing Al 203.5ixt.

Use ceramic refractory materials such as ZrOz.

Reference numeral 7 designates a carbon gas flow path for combustion of carbonaceous powder material, in which the mouthpiece 5 at the tip of the nozzle 6 directs the blowing direction of oxygen gas so that it collides with the pneumatic supply flow of carbonaceous powder material, and carbon Increases the combustibility of powdery substances. The optimum angle of intersection between the center lines of the oxygen gas flow and the pneumatic supply flow of carbonaceous powder material varies depending on the volatile content ratio and ejection speed in the carbonaceous powder material, but it is within the range of 30 to 75 degrees. Compatible.

Reference numeral 8 denotes a cooling fluid flow path in the lance outer cylinder and tip, which is essential for improving the durability of the lance used in a high-temperature reaction vessel.

(Function) A non-oxidizing substance is used for the flow path piping of the nozzle, and a heat-resistant and wear-resistant ceramic refractory material is used for the inner lining of the flow path piping. life extension,
Furthermore, the life of the lance can be extended and the structure can be simplified.

(Example) Refining was carried out using the equipment shown in FIG. 2, which is equipped with a 5 ton scale converter furnace capable of bottom-blowing oxygen gas as a reaction vessel together with a combustion lance.

In Fig. 2, 9 is a refining/combustion lance, 10 is a top-bottom blowing converter, 11 is a bottom blower that supplies oxygen and propane for cooling the tuyere, 12 is charged hot metal, and 13 is carbonaceous powder. substance (
14 is a dispenser for storing pulverized coal and transporting gas, and 14 is a dispenser for powdered chromium ore.

The structure of the combustion lance 8 is as shown in Fig. 1 above, with a stainless steel pipe used for the flow path piping, and a Pt-Pt 13wtχRh tube for mouthpiece temperature measurement on the inner periphery of the liquid pipe.
A thermocouple was wrapped around the mouthpiece, and a 3.5 mm thick pipe made of high alumina sintered material was fixed with adhesive as a lining, and a high alumina sintered material was also used for the mouthpiece.

The operating procedure is as follows: First, the inside of the converter is sufficiently preheated to bring the furnace inner wall temperature to about 900°C, and then about 4.5 tons of hot metal at 1250°C is heated.
I charged it on.

Next, the furnace was made vertical and oxygen was pumped in at 7.5Nm through the bottom tuyere 10.
ff/+tn and propane gas for tuyere cooling to 0.4
5Nmff/rnin was supplied. At the same time, the combustion lance 9 is lowered from above the furnace, and the pulverized coal 3 is
5kg/n++nx oxygen at 17.5Nm! /win was supplied to burn the pulverized coal at the nozzle outlet of the lance, and the lance 9 was fixed at a position where the generated flame would hit the hot metal.

After maintaining the temperature of the hot metal in this state until it reaches 1600°C, powdered chromium ore is supplied from the dispenser 14 at a rate of 25 kg/min for another 60 minutes to join with the pulverized coal in the middle of the piping, and the hot metal is poured into the hot metal from the combustion lance 9. Powdered chromium ore was added to. After this, the furnace was tilted to check the degree of wear on the lance nozzle, and molten iron was sampled.

The above experiment was conducted for a total of 102 heats, and approximately 300 tons of pulverized coal was used.
A total of about 460 tons of powder, including about 160 tons of chromium ore, was added into the furnace via a combustion lance, but no effect was observed on the nozzle and mouthpiece of the lance.

In addition, in order to investigate the wear amount of the lining, the lining was removed from the nozzle and its weight was measured every 10 heats, and the results were calculated as the lining weight (Ws) when the amount of powder passing through was zero.
The solid line in FIG. 3 shows the relationship between the rate of change in the lining weight (Wm) after use, that is, the wear rate and the amount of powder used.

From FIG. 3, it can be seen that the lining hardly wears out when about 72,500 kg of powder passes through it.

Furthermore, as a result of temperature measurement of the mouthpiece during operation, the maximum temperature near the nozzle tip was 1,650 t, and the melting point of the high alumina sintered body was 2o3oC, indicating that it had sufficient durability. No change was observed in the nozzle observation results after operation.

A total 6° heat operation was carried out in the same manner and with the same equipment as in the comparison example. However, the combustion lance did not have a lining, the flow path was a stainless steel tube, and the mouthpiece was also made of stainless steel.

In other words, 35 kg/win of pulverized coal is produced through the combustion lance.
and oxygen gas 17.5Nm! /min to the iron bath in the converter and the temperature of the iron bath was raised to 1600°C. After that, powdered chromium ore was supplied at a rate of 25 kg/sin, and pulverized coal was approximately 165 tons.
, about 95 tons of powdered chromium ore, totaling about 260 tons.
of powder was passed through a stainless steel tube channel within the lance.

In order to compare the relationship between the wear rate of the powder flow path and the amount of powder passing through at this time with the example, it is shown by a broken line in FIG. From FIG. 3, it can be seen that the comparative example had a higher wear rate than the example because no wear-resistant lining was used. Also all 6
It was also confirmed that the mouthpiece was partially melted and damaged in 9 out of 0 heats.

(Effects of the Invention) In this invention, the nozzle of the lance is equipped with a lining made of a ceramic refractory material with excellent heat resistance and wear resistance.
The re-lance structure can also be simplified since nozzle cooling fluid is not required.

Furthermore, by arranging a thermocouple along the inner periphery of the nozzle facing the back surface of the lining, it is possible to measure the temperature at the tip of the nozzle, and also to detect holes in the lining due to wear.

[Brief explanation of drawings]

Figure 1 is a sectional view of the lance, Figure 2 is an explanatory diagram of the refining equipment, and Figure 3 is a graph showing the relationship between the wear rate and the amount of powder passing through. ■...Flow path 2...Lining 3...
・Flow path piping 4...Thermocouple 6...Nozzle Figure 1

Claims (1)

[Claims] 1. A combustion lance that emits a flame toward a charge in a metal refining reaction vessel through contact between a pneumatic feed stream of carbonaceous powder material and an oxygen stream surrounding it. A lance for refining and combustion, characterized in that the nozzle for pneumatically supplying carbonaceous powder material has a lining of a heat-resistant and wear-resistant ceramic refractory material. 2. The lance according to claim 1, comprising a thermocouple arranged along the inner periphery of the nozzle and facing the back surface of the lining.