JPS593438B2 - Pituchigan Yutaikaseihin No Tankasokushinshiyorihohou - Google Patents

Description

[Detailed Description of the Invention] Pitch-containing refractory products, such as refractory bricks and crucibles impregnated with pitch, and refractory bases that are compression-molded with pitch as a binder, are fired to carbonize the pitch. It is necessary to fix the pitch in order to increase its fire resistance and durability. However, in conventional normal-pressure direct firing furnaces, the outflow and blow-out of molten pitch cannot be suppressed, and the pitch carbonization fixed yield is 20 times the amount of impregnated pitch. In addition, a large amount of combustion exhaust gas is contaminated with pitch gas, making it difficult to prevent air pollution.

The present invention focuses on the fact that pitch is a mixture of a high viscosity solute component with a high melting point and boiling point, and a low viscosity solvent component with a low melting point and boiling point. The contained refractory product is placed in a pressure- and heat-resistant tank, sealed and heated, and inert gas is pumped to suppress the outflow of molten pitch, and the pressure inside the tank is reduced to 2 to 4 k depending on the type of product.
g/Crn2G.

Reduce costs as much as possible by varying the weight from 0.5 to 2 kg/cm'G for thick ones, from 3 to 4 kg/cm'G for ones with large porosity, and from 0.5 to 1.5 kim' G for small ones. By setting a combination that allows for the prevention of the molten pitch contained inside the product from flowing out, the solvent components contained in the molten pitch are used to prevent the pitch from carbonizing and fixing, and the volatile components are diffused to the outside. It enhances the action, lowers the vapor partial pressure of volatile components in the atmosphere, increases the evaporation rate, and makes the pitch carbonization fixed yield 35 to 45 times the amount of impregnated pitch.

This principle is based on the fact that when a product coated with a paint whose viscosity has been lowered by adding a solvent is heated to a certain atmospheric pressure, a foaming phenomenon occurs within the paint surface, and when the temperature is further increased, carbonization occurs and the atmospheric pressure This is thought to be an application of the fact that if the partial pressure of the solvent vapor in the atmosphere is lowered while suppressing foaming by increasing the pressure, a strong coating film can be formed rapidly without foaming, and when high pressure and high temperature conditions are applied, carbonization is rapidly fixed. You can easily understand it.

Similarly, the polymeric hydrocarbons that are the main components of pitch have the property of polycondensation under pressure and heating, and one of the purposes of pressure firing is to utilize this property to improve the carbonization yield.

Therefore, products that have been carbonized and fixed in a pressure firing furnace for 2 to 3 hours have a better yield of fixed carbon and are more durable than products that have been carbonized and fixed in an atmospheric pressure firing furnace for more than 10 hours. Power has also been confirmed to have positive effects.

The reason for this is that after pressurizing the pitch-containing refractory product to form a honey carbonized fixed pipe of 2 to 5 m, graphitization easily progresses when heated at high temperature in an atmospheric pressure furnace, and this graphite component is used in the refractory product. This is because it plays a key role in improving the quality of products.

Next, since the amount of the mixture of pitch gas and inert gas gradually released from the pressure firing furnace is extremely small compared to the amount of contaminated combustion exhaust gas from the normal pressure direct combustion furnace, condensation separation or Even if a method such as direct combustion oxidation is used, it can be processed economically, and the small amount of pitch gas released is the reason for increasing the carbonization yield of pitch.

Next, heating methods for pressure-resistant and heat-resistant tanks include electric heating, heat medium circulation heating, radiant tube heaters, and burner heating furnaces. Smoke can be deodorized and the combustion heat can also be used for heating.

Next, by embedding a water-cooled steel pipe in the door backing groove of the pressure- and heat-resistant tank, local cooling of the backing becomes easy and the durability of the backing can be improved.

Secondly, even if the inert gas is used by properly cooling the combustion exhaust gas and pumping it, there is no risk of creating an explosive mixture, and it can be used safely and economically.

Claims (1)

[Claims] 1 Pitch-impregnated refractory bricks, crucibles, etc., as well as refractory base material (shirashi) that has been mixed and compression-molded with pitch as a binder, are placed in a pressure- and heat-resistant tank and sealed, and 0.5 ~4.0 kg/cIIL
- While blowing an inert gas of G, the atmosphere containing the volatile pitch gas that evaporates from the entire surface of the pitch-containing refractory product by heating it to 340-400°C is gradually released from the relief valve into the water-cooled condenser. Condensing and separating pitch gas or
A pitch-containing refractory characterized by blowing into an oxidizing flame to directly oxidize, desmoke, and deodorize to prevent air pollution while firing under pressure for a short period of 2 to 3 hours to carbonize and fix the pitch with a high yield. A method for promoting carbonization of products.