Method and system for producing olefins by steam cracking of a heavier hydrocarbon

{
  "publication_number": "US2026103432A1",
  "country": "US",
  "kind": "A1",
  "title": "Method and system for producing olefins by steam cracking of a heavier hydrocarbon",
  "abstract": "A process for producing olefins by steam cracking of a heavier hydrocarbon includes the steps of: subjecting a heavier hydrocarbon to a first separation to obtain a first vapour stream and a first liquid stream, partially condensing (second separation) the first vapour stream to obtain a condensate (third heavier fraction), introducing at least a portion of the third heavier fraction into the first liquid stream to obtain a first modified liquid stream, subjecting the first modified liquid stream to a third separation to obtain a second vapour stream and a second liquid stream, and carrying out steam cracking on the second vapour stream to obtain a cracked gas effluent containing the olefins. This process inhibits the coking of the convection zone, and provide a high utilization rate of heavier hydrocarbon (crude oil) and a high ethylene yield.",
  "claims": [
    "1. A process for producing olefins by steam cracking of a heavier hydrocarbon, comprising the steps of: subjecting the heavier hydrocarbon to a first separation (such as flash) to obtain a first vapour stream and a first liquid stream, subjecting the first vapour stream to a partial condensation (such as fractional distillation, referred to as the second separation) to obtain a condensate (referred to as the third heavier fraction, preferably having an initial boiling temperature of 165° C. or higher, more preferably having a distillation range of 180-380° C.), introducing at least a portion (e.g., 50 wt % or higher or 80 wt % of higher of its total weight) of the third heavier fraction into the first liquid stream to obtain a first modified liquid stream, subjecting the first modified liquid stream to a third separation (e.g., flash) to obtain a second vapour stream and a second liquid stream, and subjecting the second vapour stream to a steam cracking to obtain a cracked gas effluent comprising olefins. 2. The process according to claim 1, wherein the final boiling temperature of the heavier hydrocarbon is 540° C. or higher (preferably having an initial boiling temperature of 15° C. and a final boiling temperature of 750° C. or higher), and/or the API index of the heavier hydrocarbon is not less than 32 (preferably 38 or more), and/or the content of non-volatile components of the heavier hydrocarbon is 25 wt % or less (preferably 0.1-5.5 wt %), based on the total weight of the heavier hydrocarbon, and/or the potential aromatic content of the heavier hydrocarbon is 10-40 wt %, based on the total weight of the heavier hydrocarbon. 3. The process according to claim 1, wherein the heavier hydrocarbon is at least one selected from the group consisting of paraffin based crude oil, intermediate based crude oil, naphthenic based crude oil, condensate oil, and refined products. 4. The process according to claim 1, wherein the heavier hydrocarbon is preheated to a temperature of 200-400° C. (preferably 240-300° C.) prior to the first separation. 5. The process according to claim 1, wherein the first vapour stream has a content of non-volatile components of 0.5 wt % or less, based on the total weight of the first vapour stream. 6. The process according to claim 1, wherein the first vapour stream is subjected to the second separation to obtain at least a third lighter fraction (preferably having a final boiling temperature of 90° C. or lower), a first intermediate fraction (preferably having a distillation range of 80-170° C.) and the third heavier fraction. 7. The process according to claim 6, further comprising subjecting the first intermediate fraction to at least one treatment selected from the group consisting of reforming treatment, refinery processing, and isomeric separation. 8. The process according to claim 1, wherein the third heavier fraction has a content of non-volatile components of 1 wt % or less (preferably 0.5 wt % or less), based on the total weight of the third heavier fraction. 9. The process according to claim 1, wherein the weight ratio of the third heavier fraction to the first liquid stream is 5-25% (preferably 15-18%). 10. The process according to claim 1, wherein the first modified liquid stream is subjected to a first mixing with a primary dilution steam to obtain a first mixed stream, then the first mixed stream is subjected to a first heating, then the first mixed stream after the first heating is subjected to a second mixing with a secondary dilution steam to obtain a second mixed stream, and then the second mixed stream is subjected to the third separation to obtain the second vapour stream and the second liquid stream. 11. The process according to claim 10, wherein the temperature of the primary dilution steam is 180-400° C., preferably 200-350° C., and/or the temperature of the first mixed stream after the first heating is 400° C. or lower, preferably 250-350° C., and/or the temperature of the secondary dilution steam is 400-630° C., preferably 450-600° C., and/or the weight ratio of the first modified liquid stream to the primary dilution steam is 1:(0.1-0.5), preferably 1:(0.2-0.4), and/or the weight ratio of the first modified liquid stream to the secondary dilution steam is 1:(0.2-0.8), preferably 1:(0.3-0.65), and/or the temperature of the second mixed stream is 280-360° C. (preferably 310-340° C.). 12. The process according to claim 1, wherein a liquid hydrocarbon is further introduced into the first liquid stream, and/or into the first modified liquid stream, and/or into the first mixed stream, at a weight ratio of the liquid hydrocarbon to the first liquid stream of 1:(0.45-0.85) (preferably 1:(0.5-0.7)). 13. The process according to claim 1, wherein in the first separation, the vaporization rate of the heavier hydrocarbon (referred to as the first vaporization rate) is 15-60%, preferably 25-45%, and in the third separation, the vaporization rate of the first modified liquid stream or the second mixed stream (referred to as the second vaporization rate) is 40-80%, preferably 50-70%. 14. The process according to claim 1, wherein the difference (absolute value) between the first vaporization rate and the second vaporization rate is 15-40% (preferably 20-30%). 15. The process according to claim 1, wherein the first modified liquid stream or the second mixed stream is subjected to the third separation to obtain a vapour stream (referred to as the primary vapour stream) and a liquid stream (referred to as the primary liquid stream), and at least a portion (such as 50 wt % or less or 20 wt % or less of the total weight) of the third heavier fraction and/or a separation aid (also referred to as a cooling aid) is counter-currently contacted with the primary vapour stream to obtain the second vapour stream. 16. The process according to claim 15, wherein the weight ratio of the second vapour stream to the third heavier fraction is 1:(0.01-0.35), preferably 1:(0.05-0.2), and/or the weight ratio of the second vapour stream to the separation aid is 1:(0.01-0.2), preferably 1:(0.05-0.15). 17. The process according to claim 15, wherein the primary vapour stream is firstly counter-currently contacted with the separation aid, and then counter-currently contacted with the third heavier fraction, or the primary vapour stream is firstly counter-currently contacted with the third heavier fraction, and then counter-currently contacted with the separation aid. 18. The process according to claim 15, wherein the separation aid is at least one selected from the group consisting of a liquid hydrocarbon and liquid water. 19. The process according to claim 18, wherein the primary vapour stream is firstly counter-currently contacted with liquid water, and then counter-currently contacted with the liquid hydrocarbon, or the primary vapour stream is firstly counter-currently contacted with the liquid hydrocarbon, and then counter-currently contacted with liquid water, or the primary vapour stream is counter-currently contacted with liquid water and the liquid hydrocarbon at the same time. 20. The process according to claim 12, wherein the liquid hydrocarbon has a final boiling point of 200-540° C. (preferably 250-450° C. or 300-400° C.), based on the total weight of the liquid hydrocarbon, and is preferably at least one selected from the group consisting of heavy naphtha, aviation kerosene oil and diesel oil. 21. The process according to claim 1, wherein the second vapour stream is subjected to a second heating to a temperature of 500-600° C. (preferably 510-550° C.) prior to the steam cracking, and the content of non-volatile components of the second vapour stream is 1 wt % or less (preferably 0.5 wt % or less), based on the total weight of the second vapour stream. 22. A system for producing olefins by the steam cracking of a heavier hydrocarbon, comprising: a first vapour-liquid separator (8) configured to perform a first separation (such as flash) of the heavier hydrocarbon, to obtain a first vapour stream and a first liquid stream, a separator, such as a separation column (7), configured to partially condense (e.g. by fractional distillation, referred to as a second separation) the first vapour stream to obtain a condensate (referred to as a third heavier fraction, preferably having an initial boiling temperature of 165° C. or higher, more preferably having a distillation range of 180-380° C.), a introduction means configured to introduce at least a portion (such as 50 wt % or higher or 80 wt % or higher of its total weight) of the third heavier fraction into the first liquid stream to obtain a first modified liquid stream, a second vapour-liquid separator (9) configured to perform a third separation (such as flash) of the first modified liquid stream to obtain a second vapour stream and a second liquid stream, a steam cracker configured to steam-crack the second vapour stream to obtain a cracked gas effluent comprising olefins."
  ],
  "description_excerpt": "The present application relates to the technical field of petrochemical industry, particularly to a process and a system for producing olefin by steam cracking of a heavier hydrocarbon.\n\nCompared with the traditional cracking feedstock, when used as the feedstock of steam cracking furnace, heavier hydrocarbons (crude oil and the like) have the problems of high final boiling point (higher than 520° C.), containing impurities such as resin, asphaltene and the like, difficult vaporization, easy coking and the like, so that the design of the cracking furnace and the process of production need to be modified and improved correspondingly to adapt to the characteristics of the heavier hydrocarbons (crude oil and the like).\n\nCN111196936A discloses a combined processing method and plant for producing olefin by direct cracking of crude oil, which is used for producing olefin directly from crude oil, and comprises removing impurities such as water, metals, and non-metals in the feed by pretreatment such as desalting and dewatering, then feeding the treated feed into the first tube bank in convection zone of an ethylene cracking furnace for heating, feeding the heated feed into a vapour-liquid separator, feeding the separated diesel oil and lighter gaseous hydrocarbon into the second tube bank of the convection zone and a radiant zone for steam cracking reaction to produce olefin.",
  "cpc": [
    "C07C 4/04"
  ],
  "assignees": [
    "China Petroleum and Chemical Corp",
    "Sinopec Engineering Inc"
  ],
  "inventors": [
    "Xiou He",
    "Defei WU",
    "Chuanhong FAN",
    "Jiangfeng LIN",
    "Zizong WANG",
    "Yonghua Zhao",
    "Fei Bai",
    "Chen Shao",
    "Jia Xiao",
    "Yu Shi"
  ],
  "filing_date": "2023-07-25",
  "publication_date": "2026-04-16",
  "priority_date": "2022-07-25",
  "application_number": "US-202318996551-A",
  "cited_by_count": 0
}