Method for washing furnace through mixed blowing of carbon dioxide and oxygen

Abstract

The invention discloses a method for washing a furnace through mixed blowing of carbon dioxide and oxygen. The method comprises the following steps that S1, furnace washing preparation is conducted; s2, furnace cap washing: when the oxygen lance descends to an oxygen lance oxygen opening point set at the position of a furnace mouth, opening a CO2 and O2 regulating valve of the oxygen lance, mixing and top blowing CO2 and O2 according to the proportion that CO2 accounts for 3%-5%, and repeatedly sliding the oxygen lance up and down to mix and top blow CO2-O2 and wash furnace cap bonded slag for 3-8 minutes each time; s3, a furnace body is washed, specifically, an oxygen lance is descended to the position below a furnace opening, CO2 and O2 adjusting valves are opened when the position of a furnace cap is avoided and the oxygen lance is set at an oxygen opening point, and CO2 and O2 are mixed according to the proportion that CO2 accounts for 5%-10% and are subjected to top blowing; s4, the furnace bottom is washed, specifically, the furnace bottom is mainly soaked, and the soaking time is 20-30 min after the furnace body is washed every time; and S5, furnace washing is finished, specifically, the CO2 adjusting valve and the O2 adjusting valve are closed, the oxygen lance is lifted out, and furnace washing slag is poured into a slag tank.

Description

Technical Field

[0001] The invention relates to the technical field of stainless steel smelting, and in particular to a method for washing a furnace by using a mixture of carbon dioxide and oxygen for spraying. Background Art

[0002] The main purpose of furnace washing is to wash away the slag layer, residual steel, and brick joints, while preventing the high temperature and strong oxidizing properties of the furnace washing slag, and improper operation that may cause the furnace shell to turn red and leak slag, oxygen lance leaking, and slag tank burning. If CO2 can be used as a resource in the steel metallurgical process, it will add a new way to use CO2 as a resource. While achieving CO2 emission reduction, it can also make full use of the weak oxidizing properties and cooling effects of CO2 to improve the overall effect of furnace washing. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen.

[0004] In order to achieve the above object, the technical solution of the present invention is as follows: A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, comprising the following steps: S1, furnace washing preparation, the last pouring of smelting, the tapping temperature is controlled in the range of 1430-1450℃, 1 / 3 of the slag of the last heat of steel is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen lance is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen lance, CO2 and O2 are mixed and top-blown at a ratio of 3%-5% CO2, and the oxygen lance is repeatedly slid up and down to mix CO2-O2 and top-blow to wash the sticky slag on the furnace cap. Each time is 3-8 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen lance, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 3-4 times, wash the slag layer at the furnace mouth thin or wash it off, and then wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounts for 5%-10% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 5-15 minutes, each time after the time is up, close the CO2 and O2 regulating valves, take out the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 3-4 times, wash the slag layer of the furnace body thin or wash it away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, washing the furnace bottom: the furnace bottom is mainly soaked, and the soaking time is 20-30 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, the furnace washing is stopped and the furnace washing is finished; if the furnace bottom brick seams are not washed out, the oxygen gun is lowered to the oxygen gun opening point set at the low position of the furnace body, and the CO2 and O2 regulating valves are opened. CO2 and O2 are mixed and blown at a ratio of 5%-10% of CO2 to wash the sticky slag at the bottom of the furnace. Each time is 3-8 minutes. Observe the slag layer at the bottom of the furnace each time. If the furnace bottom brick seams are washed out, stop washing the furnace; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.

[0005] The beneficial effects of the present invention are as follows: the present invention applies CO2 as a resource to the steel metallurgical process, adds a new way to utilize CO2 as a resource, and while achieving CO2 emission reduction, can also make full use of the weak oxidizing property of CO2 and the cooling effect to improve the overall furnace washing effect. The main purpose of furnace washing is to wash away the slag layer and residual steel, wash out the brick joints, and prevent the possible problems of high temperature and strong oxidizing property of furnace washing slag, reddening of the furnace shell, leakage of oxygen lance, and burning of slag tanks due to improper operation. It can effectively avoid the slag layer of the furnace cap, furnace body, and furnace bottom that cannot be effectively removed and damages other parts of the furnace lining, and even causes a serious accident of furnace body leakage. DETAILED DESCRIPTION

[0006] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In addition, in the following description, the description of known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0007] Example 1 A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, comprising the following steps: S1, furnace washing preparation, the last pouring of smelting, the tapping temperature is controlled at 1430℃, 1 / 3 of the slag of the last batch of steel is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen lance is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen lance, CO2 and O2 are mixed and top-blown at a ratio of 3% CO2, and the oxygen lance is repeatedly slid up and down to mix and top-blow CO2-O2 to wash the sticky slag on the furnace cap. Each time is 3 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen lance, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 3 times, wash the slag layer at the furnace mouth thin or wash it off, and then wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounts for 5% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 5 minutes, each time after the time is up, close the CO2 and O2 regulating valves, take out the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 3 times, wash the slag layer of the furnace body thin or wash it away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, washing the furnace bottom: the furnace bottom is mainly soaked, and the soaking time is 20 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, the furnace washing is stopped and the furnace washing is finished; if the furnace bottom brick seams are not washed out, the oxygen gun is lowered to the oxygen gun opening point set at the low position of the furnace body, and the CO2 and O2 regulating valves are opened. CO2 and O2 are mixed and top-blown at a ratio of 5% CO2 to wash the sticky slag at the bottom of the furnace. Each time is 3 minutes, and the slag layer at the bottom of the furnace is observed each time. If the furnace bottom brick seams are washed out, the furnace washing is stopped; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.

[0008] Example 2 A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, comprising the following steps: S1, furnace washing preparation, the last pouring of smelting, the tapping temperature is controlled at 1450℃, 1 / 3 of the slag of the last batch of steel is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen gun is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen gun, CO2 and O2 are mixed and blown top-blown at a ratio of 5% CO2, and the oxygen gun is repeatedly slid up and down to mix and blow CO2-O2 top-blown to wash the sticky slag on the furnace cap. Each time is 8 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen gun, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 4 times, wash the slag layer at the furnace mouth thin or wash it off, and then wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounts for 10% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 15 minutes, each time after the time is up, close the CO2 and O2 regulating valves, take out the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 4 times, wash the slag layer of the furnace body thin or wash it away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, furnace bottom washing: the furnace bottom is mainly soaked, and the soaking time is 30 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, the furnace washing is stopped and the furnace washing is finished; if the furnace bottom brick seams are not washed out, the oxygen gun is lowered to the oxygen gun opening point set at the low position of the furnace body, and the CO2 and O2 regulating valves are opened. CO2 and O2 are mixed and top-blown at a ratio of 10% CO2 to wash the sticky slag at the bottom of the furnace. Each time is 8 minutes. Observe the slag layer at the bottom of the furnace each time. If the furnace bottom brick seams are washed out, stop washing the furnace; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.

[0009] Example 3 A 100-ton converter of a steelmaking plant uses a φ219mm oxygen lance. The oxygen lance is used for normal smelting. The oxygen lance is connected to the CO2 flow control valve, O2 flow control valve and oxygen lance control system. The converter is ready for cleaning and preparation for subsequent dismantling. The details are as follows: A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, comprising the following steps: S1, furnace washing preparation, the last pouring of smelting, the tapping temperature is controlled at 1440℃, 1 / 3 of the slag of the last heat of steel is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen lance is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen lance, CO2 and O2 are mixed and top-blown at a ratio of 3% CO2, and the oxygen lance is repeatedly slid up and down to mix and top-blow CO2-O2 to wash the sticky slag on the furnace cap. Each time is 3 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen lance, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 3 times, wash the slag layer at the furnace mouth thin or wash it off, and then wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounted for 8% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 5 minutes, each time after the time is up, close the CO2 and O2 regulating valves, lift the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 3 times, wash the slag layer of the furnace body thin or wash away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, washing the furnace bottom: the furnace bottom is mainly soaked, and the soaking time is 23 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, the furnace washing is stopped and the furnace washing is finished; if the furnace bottom brick seams are not washed out, the oxygen gun is lowered to the oxygen gun opening point set at the low position of the furnace body, and the CO2 and O2 regulating valves are opened. CO2 and O2 are mixed and top-blown at a ratio of 5% CO2 to wash the sticky slag at the bottom of the furnace. Each time is 3 minutes. Observe the slag layer at the bottom of the furnace each time. If the furnace bottom brick seams are washed out, stop washing the furnace; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.

[0010] Example 4 A 100-ton steelmaking converter uses a φ219mm oxygen lance and a spare oxygen lance. The spare oxygen lance is connected to the CO2 flow control valve, O2 flow control valve and oxygen lance control system. The spare oxygen lance is moved to the smelting position, and the converter is ready for furnace washing and preparation for subsequent furnace dismantling. The details are as follows: A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, comprising the following steps: S1, furnace washing preparation, the last pouring of smelting, the tapping temperature is controlled at 1440℃, 1 / 3 of the slag of the last heat of steel is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen lance is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen lance, CO2 and O2 are mixed and top-blown at a ratio of 4% CO2, and the oxygen lance is repeatedly slid up and down to mix and top-blow CO2-O2 to wash the sticky slag on the furnace cap. Each time is 3 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen lance, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 4 times, wash the slag layer at the furnace mouth thin or wash it off, and then wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounts for 5% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 5 minutes, each time after the time is up, close the CO2 and O2 regulating valves, lift the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 4 times, wash the slag layer of the furnace body thin or wash it away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, washing the furnace bottom: the furnace bottom is mainly soaked, and the soaking time is 25 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, the furnace washing is stopped and the furnace washing is finished; if the furnace bottom brick seams are not washed out, the oxygen gun is lowered to the oxygen gun opening point set at the low position of the furnace body, and the CO2 and O2 regulating valves are opened. CO2 and O2 are mixed and top-blown at a ratio of 5% CO2 to wash the sticky slag at the bottom of the furnace. Each time is 8 minutes. Observe the slag layer at the bottom of the furnace each time. If the furnace bottom brick seams are washed out, stop washing the furnace; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.

[0011] Example 5 A 100-ton converter of a steelmaking plant uses a φ219mm oxygen lance. The oxygen lance is used for normal smelting. The oxygen lance is connected to the CO2 flow control valve, O2 flow control valve and oxygen lance control system. The converter is ready for cleaning and preparation for subsequent dismantling. The details are as follows: A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, comprising the following steps: S1, furnace washing preparation, the last pouring of smelting, the tapping temperature is controlled at 1450℃, 1 / 3 of the slag of the last batch of steel is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen lance is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen lance, CO2 and O2 are mixed and top-blown at a ratio of 5% CO2, and the oxygen lance is repeatedly slid up and down to mix and top-blow CO2-O2 to wash the sticky slag on the furnace cap. Each time is 4 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen lance, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 4 times, and after the slag layer at the furnace mouth is thinned or washed away, wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounts for 10% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 5 minutes, each time after the time is up, close the CO2 and O2 regulating valves, lift the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 4 times, wash the slag layer of the furnace body thin or wash it away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, washing the furnace bottom: the furnace bottom is mainly soaked, and the soaking time is 20 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, stop washing the furnace and the furnace washing is completed; if the furnace bottom brick seams are not washed out, lower the oxygen gun to the oxygen gun opening point set at the low position of the furnace body, open the CO2 and O2 regulating valves, CO2 and O2, with a ratio of 5% CO2 mixed top blowing, wash the furnace bottom sticky slag, each time for 3 minutes, observe the furnace bottom slag layer after 2 times, if the furnace bottom brick seams are washed out, stop washing the furnace; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.

[0012] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for cleaning a furnace by spraying a mixture of carbon dioxide and oxygen, characterized in that: The following steps are involved: S1. Preparation for furnace washing: For the last pouring of smelting, the tapping temperature is controlled within the range of 1430-1450°C. After smelting the last batch of steel, 1 / 3 of the slag is poured out, and 2 / 3 of the slag is retained for furnace washing; S2. Washing the furnace cap: when the oxygen lance is lowered to the oxygen opening point set at the furnace mouth, open the CO2 and O2 regulating valves of the oxygen lance, CO2 and O2 are mixed and top-blown at a ratio of 3%-5% CO2, and the oxygen lance is repeatedly slid up and down to mix CO2-O2 and top-blow to wash the sticky slag on the furnace cap. Each time is 3-8 minutes. After the time is up, close the CO2 and O2 regulating valves, pull out the oxygen lance, pour 1 / 3 of the washed slag into the slag pot, leave 2 / 3 of the washed slag in the furnace, observe the slag layer at the furnace mouth, wash the furnace cap 3-4 times, wash the slag layer at the furnace mouth thin or wash it off, and then wash the furnace body downwards in sequence; S3, washing the furnace body: lower the oxygen lance to the bottom of the furnace mouth, avoid the furnace cap position, and when the oxygen lance oxygen opening point is set, open the CO2 and O2 regulating valves, CO2 and O2, CO2 accounts for 5%-10% of the ratio of top blowing, and repeatedly slide the oxygen lance up and down to mix the top blowing CO2-O2, wash the furnace body sticky slag, each time for 5-15 minutes, each time after the time is up, close the CO2 and O2 regulating valves, take out the oxygen lance, pour 1 / 2 of the washed slag into the slag pot, leave 1 / 2 of the washed slag in the furnace, observe the slag layer of the furnace body, wash the furnace body 3-4 times, wash the slag layer of the furnace body thin or wash it away, wash out the brick seams, and then wash the furnace bottom downwards in sequence; S4, washing the furnace bottom: the furnace bottom is mainly soaked, and the soaking time is 20-30 minutes after each furnace body washing. After the furnace body washing is completed, if the furnace bottom brick seams are washed out, the furnace washing is stopped and the furnace washing is finished; if the furnace bottom brick seams are not washed out, the oxygen gun is lowered to the oxygen gun opening point set at the low position of the furnace body, and the CO2 and O2 regulating valves are opened. CO2 and O2 are mixed and blown at a ratio of 5%-10% of CO2 to wash the sticky slag at the bottom of the furnace. Each time is 3-8 minutes. Observe the slag layer at the bottom of the furnace each time. If the furnace bottom brick seams are washed out, stop washing the furnace; S5. End of furnace washing: close the CO2 and O2 regulating valves, raise the oxygen gun, and pour the furnace washing slag into the slag pot.