TH27827B - Reduction of coke formation in fission reactors - Google Patents

Abstract

DC60 (03/09/50) This invention relates to the cracking of hydrocarbons or other organic compounds. According to the invention, a process is provided for reducing coke formation on the metal walls of reactors for the cracking of hydrocarbons or other organic compounds and on the metal walls of heat exchangers placed adjacent to the cracking reactors. The metal surfaces in contact with the organic compounds being cracked are initially treated with steam containing at least one silicon compound and at least one sulfur compound at temperatures between 300 and 1100 °C for 0.5 to 12 hours. The process described in the invention significantly reduces coke formation on the metal walls of the cracking reactors and heat exchangers. This invention relates to the cracking of hydrocarbons or other organic compounds. According to the invention, a process is provided for reducing coke formation on the metal walls of reactors for the cracking of hydrocarbons or other organic compounds and on the metal walls of heat exchangers placed adjacent to the cracking reactors. The metal surfaces in contact with the organic compounds being cracked are initially treated with steam containing at least one silicon compound and at least one sulfur compound. At least one silicon and at least one sulfur compound are heated between 300 and 1100 °C for 0.5 to 12 hours. The invented process significantly reduces coke formation on the metal walls of cracking reactors and heat exchangers.

Claims (12)

1. The process for reducing coking on the metal walls of hydrocarbon or other organic compound cracking reactors and on the metal walls of the heat exchanger placed adjacent to the cracking reactor is characterized by the initial action of the cracking reactor with a steam stream containing hexamethyl disiloxane and dimethyl disulfide at temperatures between 750 and 1050 °C for 1 to 6 hours, and the initial action of the heat exchanger placed adjacent to the cracking reactor with a steam stream containing hexamethyl disiloxane and dimethyl disulfide at temperatures between 400 and 700 °C for 1 to 6 hours, where the mass concentrations of dimethyl disulfide and hexamethyl disulfide are concentrated. The siloxane concentration in steam flows is between 50 and 500 parts per million, and the Si:S atomic ratio is between 2:1 and 1:2. 2. The process under claim 1 in which steam is used as a carrier fluid containing added nitrogen, hydrogen, methane, or ethane. 3. The process under claim 1 or 2, where the mass concentration of dimethyl disulfide and hexamethyl disiloxane in the steam stream is between 100 and 3000 parts per million. 4. Processes under claim 1 or 2 where the absolute pressure varies between 1 bar (1 x 10⁵ Pascals) and 20 bar (20 x 10⁵ Pascals). 5. The process under claim 4, where the absolute pressure varies between 1 bar (1 x 10⁵ Pascals) and 5 bar (5 x 10⁵ Pascals). 6. The process stipulated in claim 1 or 2, following the initial action, involves the addition of dimethyl disulfide and/or hexamethyl disiloxane to the feed of the organic compound to be decomposed. 7. The process under claim 6 in which the Si:S atomic ratio does not exceed 2:1 during fission. 8. The process according to claim 7, in which the Si:S atomic ratio is less than or equal to 1:2 during fission. 9. The process pursuant to claim paragraph 6 shall involve the addition of an organic compound to be decomposed to the feedstock, comprising dimethyl disulfide and hexamethyl disiloxane, in quantities such that the Si:S atomic ratio shall not exceed 2:1, and the silicon concentration shall not exceed 500 parts per million. 10. The process pursuant to claim clause 9 shall involve the addition of an organic compound to be decomposed to the feedstock, comprising dimethyl disulfide and hexamethyl disiloxane in quantities such that the Si:S atomic ratio shall be less than or equal to 1:2, and the silicon concentration shall not exceed 500 parts per million. 11. The process under claim 6, in which the amount of dimethyl disulfide is concentrated by mass of sulfur in the organic compound to be decompose to between 10 and 1000 parts per million. 12. The process pursuant to claim 11, where the mass concentration of sulfur is between 20 and 300 parts per million.