APPARATUSES AND METHODS FOR HYDROTREATING COKER KEROSENE

- UOP LLC

Embodiments of apparatuses and methods for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream are provided. In one example, a method comprises splitting a feed comprising coker kerosene into first and second feed streams. The first feed stream is heated to form a heated first feed stream. The second feed stream is partially heated to form a partially heated second feed stream. The heated first feed stream is contacted with a first hydrotreating catalyst to form a first hydrotreated intermediate stream. The first hydrotreated intermediate stream is combined with the partially heated second feed stream to form a partially quenched first hydrotreated intermediate combined stream. The partially quenched first hydrotreated intermediate combined stream is contacted with a second hydrotreating catalyst to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

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Description
TECHNICAL FIELD

The technical field relates generally to apparatuses and methods for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream, and more particularly relates to apparatuses and methods that limit a temperature rise during the hydrotreating of coker kerosene or other thermally or catalytically cracked hydrocarbon stream.

BACKGROUND

Delayed cokers are processing units used by refiners to thermally crack heavy residues like vacuum and residual oils from petroleum crude oil, shale oil, and the like. The vacuum and residual oils contain heavy, long chain hydrocarbons (e.g., C13+ hydrocarbons) that are thermally cracked to produce lighter distillates such as coker gas oil and the like for downstream recovery. Coker kerosene is one of the liquid products obtained from Delayed Coking and typically comprises sulfur, nitrogen, and various C8-C22 hydrocarbons including paraffins, naphthenes, aromatics, a substantial amount of olefins, and possibly some di-olefins having boiling points at atmospheric pressure of from about 140 to about 279° C.

To upgrade the value of coker kerosene, refiners are hydrotreating the coker kerosene to remove contaminants (e.g., sulfur and nitrogen) and to hydrogenate (i.e., saturated) the olefins to form additional paraffins. The paraffins can be extracted from the upgraded coker kerosene and used, for example, as solvent or as a raw material for the production of alkyl benzene. The relatively high heat of saturation of olefins and substantial olefin content of the coker kerosene can cause a significant temperature rise in a hydrotreating reactor during hydrotreating. To control the temperature rise, some refiners recycle a portion of the hydrotreated effluent by combining the recycled effluent with a coker kerosene feed to the hydrotreating reactor to dilute the olefin content of the feed. By diluting the feed's olefin content, the heat generated during hydrogenation of the olefins is reduced to limit the temperature rise in the hydrotreating reactor. Unfortunately, recycling a portion of the hydrotreated effluent increases the duty on the hydrotreating reactor, negatively impacts the hydraulics of the system, and increases the operating and capital costs.

Accordingly, it is desirable to provide apparatuses and methods for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream that limit a temperature rise during hydrotreating. Additionally, it is desirable to provide apparatuses and methods for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream while minimizing additional equipment and/or operational cost. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.

BRIEF SUMMARY

Apparatuses and methods for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream are provided herein. In accordance with an exemplary embodiment, a method for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream comprises the steps of splitting a feed that comprises coker kerosene or other thermally or catalytically cracked hydrocarbon stream and optionally straight run kerosene into a first feed stream and a second feed stream. The first feed stream is heated to form a heated first feed stream. The second feed stream is partially heated to form a partially heated second feed stream that is at a first lower temperature than the heated first feed stream. The heated first feed stream is contacted with a first hydrotreating catalyst in the presence of hydrogen at first hydrotreating conditions effective to form a first hydrotreated intermediate stream. The first hydrotreated intermediate stream is combined with the partially heated second feed stream to form a partially quenched first hydrotreated intermediate combined stream. The partially quenched first hydrotreated intermediate combined stream is contacted with a second hydrotreating catalyst in the presence of hydrogen at second hydrotreating conditions effective to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

In accordance with another exemplary embodiment, a method for hydrotreating coker kerosene is provided. The method comprises the steps of heating a first straight run kerosene feed stream to form a heated first straight run kerosene feed stream. A first coker kerosene feed stream is partially heated to form a partially heated first coker kerosene feed stream that is at a first lower temperature than the heated first straight run kerosene feed stream. The heated first straight run kerosene feed stream is introduced to a first catalyst bed that contains a first hydrotreating catalyst in the presence of hydrogen and that is operating at first hydrotreating conditions effective to form a first hydrotreated intermediate stream. The first hydrotreated intermediate stream is combined with the partially heated first coker kerosene feed stream to form a partially quenched first hydrotreated intermediate combined stream. The partially quenched first hydrotreated intermediate combined stream is introduced to a second catalyst bed that contains a second hydrotreating catalyst in the presence of hydrogen and that is operating at second hydrotreating conditions effective to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

In accordance with another exemplary embodiment, an apparatus for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream is provided. The apparatus comprises a fluid circuit configured to split a feed comprising coker kerosene or other thermally or catalytically cracked hydrocarbon stream and optionally straight run kerosene into a first feed stream and a second feed stream. A heater is configured to receive and heat the first feed stream to form a heated first feed stream. A heat exchanger is configured to receive and partially heat the second feed stream to form a partially heated second feed stream that is at a lower temperature than the heated first feed stream. A hydrotreating reactor is configured to receive and hydrotreat the heated first feed stream and the partially heated second feed stream to form a hydrotreated effluent. The hydrotreating reactor comprises a first catalyst bed that contains a first hydrotreating catalyst and is configured to receive the heated first feed stream for contact with the first hydrotreating catalyst in the presence of hydrogen at first hydrotreating conditions effective to form a first hydrotreated intermediate stream. The hydrotreating reactor is configured to combine the first hydrotreated intermediate stream with the partially heated second feed stream to form a partially quenched first hydrotreated intermediate combined stream. A second catalyst bed contains a second hydrotreating catalyst and is configured to receive the partially quenched first hydrotreated intermediate combined stream for contact with the second hydrotreating catalyst in the presence of hydrogen at second hydrotreating conditions effective to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and wherein:

FIG. 1 schematically illustrates an apparatus and method for hydrotreating coker kerosene in accordance with an exemplary embodiment; and

FIG. 2 schematically illustrates an apparatus and method for hydrotreating coker kerosene in accordance with another exemplary embodiment.

 DETAILED DESCRIPTION

The following Detailed Description is merely exemplary in nature and is not intended to limit the various embodiments or the application and uses thereof. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

Various embodiments contemplated herein relate to apparatuses and methods for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream. The exemplary embodiments taught herein provide a feed that comprises coker kerosene or other thermally or catalytically cracked hydrocarbon stream. In an exemplary embodiment, the coker kerosene comprises sulfur, nitrogen, and various C8-C22 hydrocarbons including paraffins, naphthenes, aromatics, a substantial amount of olefins, and possibly some di-olefins. As used herein, Cx means hydrocarbon molecules that have “X” number of carbon atoms, Cx+ means hydrocarbon molecules that have “X” and/or more than “X” number of carbon atoms, and Cx− means hydrocarbon molecules that have “X” and/or less than “X” number of carbon atoms. As used herein, the term “paraffins” refers to a class of saturated linear or branched hydrocarbons (e.g., linear or branched alkanes) and the term “naphthenes” refers to a class of saturated cyclic hydrocarbons (e.g., cyclic alkanes). As used herein, the term “olefin” refers to a class of unsaturated aliphatic hydrocarbons having only one carbon-carbon double bond and the term “di-olefin” refers to a class of unsaturated aliphatic hydrocarbons having only two carbon-carbon double bonds.

The feed is split into a first feed stream and a second feed stream. The first feed stream is heated to form a heated first feed stream. The second feed stream is partially heated to form a partially heated second feed stream that is at a first lower temperature than the heated first feed stream. In an exemplary embodiment, the heated first feed stream has a temperature of from about 270 to about 310° C. and the partially heated second feed stream has a temperature of from about 220 to about 260° C.

The heated first feed stream is introduced to a hydrotreating reactor that contains a plurality of catalyst beds and that is operating at hydrotreating conditions. The heated first feed stream is passed along to a first catalyst bed and contacts a hydrotreating catalyst in the presence of hydrogen to hydrogenate olefins and form a first hydrotreated intermediate stream enriched with paraffins. The first hydrotreated intermediate stream is combined with the partially heated second feed stream to quench or partially cool the first hydrotreated intermediate stream, forming a partially quenched first hydrotreated intermediate combined stream. In an exemplary embodiment, the first hydrotreated intermediate stream has a temperature of from about 340 to about 390° C. and the partially quenched first hydrotreated intermediates combined stream has a temperature of from about 270 to about 310° C. The partially quenched first hydrotreated intermediate combined stream is passed along to a second catalyst bed and contacts a hydrotreating catalyst in the presence of hydrogen to further hydrotreat the partially quenched first hydrotreated intermediate combined stream to further convert olefins to paraffins. In an exemplary embodiment, by quenching the first hydrotreated intermediate stream with the partially heated second feed stream, the temperature in the hydrotreating reactor is reduced to limit the temperature rise during hydrotreating without recycling a hydrotreated effluent from the hydrotreating reactor. As such, improved temperature control during hydrotreating of the coker kerosene can be realized without substantially increasing the duty on the hydrotreating reactor, negatively impacting the hydraulics of the system, and/or substantially increasing the operating and capital costs.

FIG. 1 schematically illustrates an apparatus 10 for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream in accordance with an exemplary embodiment. As illustrated, the apparatus 10 comprises combined heat exchangers 12 and 14, a heater 16, and a hydrotreating reactor 18 in fluid communication with each other (via a fluid circuit). The combined heat exchanger 12 includes heat exchanger sections 20 and 22 and the combined heat exchanger 14 includes heat exchanger sections 24 and 26. Each of the heat exchanger sections 20, 22, 24, and 26 operate as substantially thermally independent heat exchangers. The heater 16 includes heater sections 28 and 30 that are separated by an air wall 32 so that the heater sections 28 and 30 are substantially thermally isolated from each other.

In an exemplary embodiment, the hydrotreating reactor 18 is a multi-fixed bed reactor. In particular and as illustrated, the hydrotreating reactor 18 comprises multiple catalyst beds 32, 34, 36, and 38 that are separated from each other by pre-bed spaces 40 (also referred to as quench zones), 42, and 44. In an exemplary embodiment, each of the catalyst beds 32, 34, 36, and 38 contain a hydrotreating catalyst. Hydrotreating catalysts are well known and typically comprise molybdenum (Mo), tungsten (W), cobalt (Co), and/or nickel (Ni) on a support comprised of γ-alumina.

As illustrated, a feed 46 of coker kerosene or other thermally or catalytically cracked hydrocarbon stream is introduced to the apparatus 10 as a coker kerosene stream (or other thermally or catalytically cracked hydrocarbon stream) 48. In an exemplary embodiment, the coker kerosene stream 48 has a temperature of from about 40 to about 60° C. A plurality of valves 50, 52, 54, and 56 are used to split or divide the coker kerosene stream 48 into feed streams 58, 60, 62, and 64. Valves 65, 66, 68, and 70 are used to divide a portion 71 of a H2-rich stream 72 into H2-rich streams 74, 76, 78, and 80. The remaining portion 73 of the H2-rich stream 72 is directed to the hydrotreating reactor 18 as will be discussed in further detail below. The H2-rich stream 72 may comprise recycle H2 from the apparatus 10, make-up H2, or a combination of recycle H2 and make-up H2. The H2-rich streams 74, 76, 78, and 80 are correspondingly introduced to the feed streams 58, 60, 62, and 64 so that hydrogen is present in the feed streams 58, 60, 62, and 64 for subsequent introduction to the hydrotreating reactor 18.

The feed streams 58, 60, 62, and 64 are correspondingly passed through the heat exchanger sections 20, 22, 24, and 26 for indirect heat exchange with a hydrotreated effluent 82, which will be discussed in further detail below, to form partially heated feed streams 84, 86, 88, and 90, respectively. In an exemplary embodiment, the partially heated feed streams 84, 86, 88, and 90 have a temperature of from about 220 to about 260° C. Additionally, to help control the temperatures of the partially heated feed streams 86 and 88, temperature control valve arrangements 92 and 94 are used to selectively bypass a portion of feed streams 60 and 62 around the heat exchange sections 22 and 24 for introduction to the partially heated feed streams 86 and 88, respectively.

As illustrated, the partially heated feed stream 90 exits the heat exchanger section 26 and is passed along to the heater 16 for introduction to the heater section 30. A temperature control valve arrangements 95 directs a fuel gas stream 96 to the heater section 30 for combustion to heat the partially heated feed stream 90 and form a heated feed stream 98. In an exemplary embodiment, the heated feed stream 98 has a temperature of from about 270 to about 310° C.

The heated feed stream 98 is passed along to the hydrotreating reactor 18 and introduced to the catalyst bed 32. In the catalyst bed 32, the heated feed stream 98 contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert olefins to paraffins via hydrogenation to form a hydrotreated intermediate stream 100. Additionally, sulfur and nitrogen in the heated feed stream 98 are converted to H2S and NH3, respectively. In an exemplary embodiment, the hydrotreated intermediate stream 100 is enriched with paraffins and further comprises H2S, NH3, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated intermediate stream 100 has a temperature of from about 340 to about 390° C.

The hydrotreated intermediate stream 100 is advanced to the pre-bed space 40 and combined with the partially heated feed stream 86 to partially quench or cool the hydrotreated intermediate stream 100 and form a partially quenched hydrotreated intermediate combined stream 102. In an exemplary embodiment, the partially quenched hydrotreated intermediate combined stream 102 has a temperature of from about 270 to about 310° C. As illustrated, to help control the temperature of the partially quenched hydrotreated intermediate combined stream 102, a temperature control valve arrangement 104 is used to selectively introduce a H2-rich stream 106 from the remaining portion 73 of the H2-rich stream 72 to the partially quenched hydrotreated intermediate combined stream 102. In an exemplary embodiment, the H2-rich stream 106 has a temperature of from about 60 to about 80° C.

Because the partially heated feed stream 86 contains a substantial amount of olefins, the partially quenched hydrotreated intermediate combined stream 102 contains olefins. As such, the partially quenched hydrotreated intermediate combined stream 102 is introduced to the catalyst bed 34 and contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert olefins to paraffins via hydrogenation to form a hydrotreated intermediate stream 108. Additionally, sulfur and nitrogen in the partially quenched hydrotreated intermediate combined stream 102 are converted to H2S and NH3, respectively. In an exemplary embodiment, the hydrotreated intermediate stream 108 is enriched with paraffins and further comprises H2S, NH3, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated intermediate stream 108 has a temperature of from about 340 to about 390° C.

As illustrated, the partially heated feed stream 84 exits the heat exchanger section 20 and is passed along to the heater 16 for introduction to the heater section 28. A temperature control valve arrangement 110 directs a fuel gas stream 112 to the heater section 28 for combustion to heat the partially heated feed stream 84 and form a heated feed stream 114. In an exemplary embodiment, the heated feed stream 114 has a temperature of from about 270 to about 310° C.

Both the heated feed stream 114 and the hydrotreated intermediate stream 108 are advanced into the pre-bed space 42 and combined to form a hydrotreated intermediate combined stream 116. In an exemplary embodiment, the hydrotreated intermediate combined stream 116 has a temperature of from about 270 to about 310° C. As illustrated, to help control the temperature of the hydrotreated intermediate combined stream 116, a temperature control valve arrangement 118 is used to selectively introduce a H2-rich stream 120 from the remaining portion 73 of the H2-rich stream 72 to the hydrotreated intermediate combined stream 116. In an exemplary embodiment, the H2-rich stream 120 has a temperature of from about 60 to about 80° C.

Because the heated feed stream 114 contains a substantial amount of olefins, the hydrotreated intermediate combined stream 116 contains olefins. As such, the hydrotreated intermediate combined stream 116 is introduced to the catalyst bed 36 and contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert olefins to paraffins via hydrogenation to form a hydrotreated intermediate stream 122. Additionally, sulfur and nitrogen in the hydrotreated intermediate combined stream 116 are converted to H2S and NH3, respectively. In an exemplary embodiment, the hydrotreated intermediate stream 122 is enriched with paraffins and further comprises H2S, NH3, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated intermediate stream 122 has a temperature of from about 340 to about 390° C.

The hydrotreated intermediate stream 122 is advanced into the pre-bed space 44 and combined with the partially heated feed stream 88 to partially quench or cool the hydrotreated intermediate stream 122 and form a partially quenched hydrotreated intermediate combined stream 124. In an exemplary embodiment, the partially quenched hydrotreated intermediate combined stream 124 has a temperature of from about 270 to about 310° C. As illustrated, to help control the temperature of the partially quenched hydrotreated intermediate combined stream 124, a temperature control valve arrangement 126 is used to selectively introduce a H2-rich stream 128 from the remaining portion 73 of the H2-rich stream 72 to the partially quenched hydrotreated intermediate combined stream 124. In an exemplary embodiment, the H2-rich stream 128 has a temperature of from about 60 to about 80° C.

Because the partially heated feed stream 88 contains a substantial amount of olefins, the partially quenched hydrotreated intermediate combined stream 124 contains olefins. As such, the partially quenched hydrotreated intermediate combined stream 124 is introduced to the catalyst bed 38 and contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert olefins to paraffins via hydrogenation to form the hydrotreated effluent 82. Additionally, sulfur and nitrogen in the partially quenched hydrotreated intermediate combined stream 124 are converted to H2S and NH3, respectively. In an exemplary embodiment, the hydrotreated effluent 82 is enriched with paraffins and further comprises H2S, NH3, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated effluent 82 has a temperature of from about 340 to about 390° C.

As illustrated, the hydrotreated effluent 82 is divided into portions 130 and 132 and the portions 130 and 132 are correspondingly passed through the combined heat exchangers 12 and 14 for indirect heat exchange as discussed above. Downstream from the combined heat exchangers 12 and 14, the portions 130 and 132 are combined and the hydrotreated effluent 82 exits the apparatus 10 for further downstream processing, such as, for example, to recover paraffins and remove H2S and NH3 from the hydrotreated effluent 82.

FIG. 2 schematically illustrates the apparatus 200 in accordance with another exemplary embodiment. As illustrated, the apparatus 200 is similarly configured as the apparatus 10 shown in FIG. 1 including the combined heat exchangers 12 and 14, the heater 16, and the hydrotreating reactor 18 but the feed 202 comprises coker kerosene and additionally straight run kerosene. Straight run kerosene comes from a crude column used to fractionate petroleum crude oil, shale oil, and the like and is not thermally cracked. As such, straight run kerosene typically comprises sulfur, nitrogen, and various C10+ hydrocarbons including paraffins, naphthenes, and aromatics having boiling points at atmospheric pressure of from about 150 to about 250° C. but typically contains relatively low or trace amounts of olefins.

In an exemplary embodiment, the feed 202 is introduced to the apparatus 200 as a coker kerosene stream 204 and a straight run kerosene stream 206. In an exemplary embodiment, the coker kerosene stream 204 and the straight run kerosene stream 206 independently have a temperature of from about 40 to about 60° C. Valves 52 and 54 are used to split or divide the coker kerosene stream 204 into feed streams 208 and 210 and valves 50 and 56 are used to split or divide the straight run kerosene stream 206 into feed streams 212 and 214. Valves 65, 66, 68, and 70 are used to divide a portion 71 of a H2-rich stream 72 into H2-rich streams 74, 76, 78, and 80. The remaining portion 73 of the H2-rich stream 72 is directed to the hydrotreating reactor 18 as will be discussed in further detail below. The H2-rich streams 74, 76, 78, and 80 are correspondingly introduced to the feed streams 212, 208, 210, and 214 so that hydrogen is present in the feed streams 208, 210, 212, and 214 for subsequent introduction to the hydrotreating reactor 18.

The feed streams 208, 210, 212, 214 are correspondingly passed through heat exchanger sections 20, 22, 24, and 26 of the combined heat exchangers 12 and 14 for indirect heat exchange with the hydrotreated effluent 82 to form partially heated feed streams 216, 218, 220, and 222. In an exemplary embodiment, the partially heated feed streams 216, 218, 220, and 222 have a temperature of from about 220 to about 260° C. Additionally, to help control the temperatures of the partially heated feed streams 218 and 220, temperature control valve arrangements 92 and 94 are used to selectively bypass a portion of feed streams 208 and 210 around the heat exchange sections 22 and 24 for introduction to the partially heated feed streams 218 and 220, respectively.

As illustrated, the partially heated feed stream 222 exits the heat exchanger section 26 and is passed along to the heater 16 for introduction to the heater section 30. The temperature control valve arrangement 95 directs the fuel gas stream 96 to the heater section 30 for combustion to heat the partially heated feed stream 222 and form a heated feed stream 224. In an exemplary embodiment, the heated feed stream 224 has a temperature of from about 270 to about 310° C.

The heated feed stream 224 is passed along to the hydrotreating reactor 18 and introduced to the catalyst bed 32. In the catalyst bed 32, the heated feed stream 224 contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert sulfur and nitrogen to H2S and NH3, respectively, to form a hydrotreated intermediate stream 226. In an exemplary embodiment, the hydrotreated intermediate stream 226 comprises H2S, NH3, paraffins, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated intermediate stream 226 has a temperature of from about 340 to about 390° C.

The hydrotreated intermediate stream 226 is advanced to the pre-bed space 40 and combined with the partially heated feed stream 218 to partially quench or cool the hydrotreated intermediate stream 226 and form a partially quenched hydrotreated intermediate combined stream 228. In an exemplary embodiment, the partially quenched hydrotreated intermediate combined stream 228 has a temperature of from about 270 to about 310° C. As illustrated, to help control the temperature of the partially quenched hydrotreated intermediate combined stream 228, the temperature control valve arrangement 104 is used to selectively introduce the H2-rich stream 106 from the remaining portion 73 of the H2-rich stream 72 to the partially quenched hydrotreated intermediate combined stream 228. In an exemplary embodiment, the H2-rich stream 106 has a temperature of from about 60 to about 80° C.

Because the partially heated feed stream 218 contains a substantial amount of olefins, the partially quenched hydrotreated intermediate combined stream 228 contains olefins. As such, the partially quenched hydrotreated intermediate combined stream 228 is introduced to the catalyst bed 34 and contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert olefins to paraffins via hydrogenation to form a hydrotreated intermediate stream 230. Additionally, sulfur and nitrogen in the partially quenched hydrotreated intermediate combined stream 228 are converted to H2S and NH3, respectively. In an exemplary embodiment, the hydrotreated intermediate stream 230 is enriched with paraffins and further comprises H2S, NH3, naphthenes, and aromatics. In an exemplary embodiment, the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated intermediate stream 230 has a temperature of from about 340 to about 390° C.

As illustrated, the partially heated feed stream 216 exits the heat exchanger section 20 and is passed along to the heater 16 for introduction to the heater section 28. The temperature control valve arrangements 110 directs a fuel gas stream 112 to the heater section 28 for combustion to heat the partially heated feed stream 216 and form a heated feed stream 232. In an exemplary embodiment, the heated feed stream 232 has a temperature of from about 270 to about 310° C.

Both the heated feed stream 232 and the hydrotreated intermediate stream 230 are advanced into the pre-bed space 42 and combined to form a hydrotreated intermediate combined stream 234. In an exemplary embodiment, the hydrotreated intermediate combined stream 234 has a temperature of from about 270 to about 310° C. As illustrated, to help control the temperature of the hydrotreated intermediate combined stream 234, the temperature control valve arrangement 118 is used to selectively introduce the H2-rich stream 120 from the remaining portion 73 of the H2-rich stream 72 to the hydrotreated intermediate combined stream 234. In an exemplary embodiment, the H2-rich stream 120 has a temperature of from about 60 to about 80° C.

The hydrotreated intermediate combined stream 234 is introduced to the catalyst bed 36 and contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert sulfur and nitrogen to H2S and NH3, respectively, to form a hydrotreated intermediate stream 236. In an exemplary embodiment, the hydrotreated intermediate stream 236 comprises H2S, NH3, paraffins, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated intermediate stream 236 has a temperature of from about 340 to about 390° C.

The hydrotreated intermediate stream 236 is advanced into the pre-bed space 44 and combined with the partially heated feed stream 220 to partially quench or cool the hydrotreated intermediate stream 236 and form a partially quenched hydrotreated intermediate combined stream 238. In an exemplary embodiment, the partially quenched hydrotreated intermediate combined stream 238 has a temperature of from about 270 to about 310° C. As illustrated, to help control the temperature of the partially quenched hydrotreated intermediate combined stream 238, the temperature control valve arrangement 126 is used to selectively introduce the H2-rich stream 128 from the remaining portion 73 of the H2-rich stream 72 to the partially quenched hydrotreated intermediate combined stream 238. In an exemplary embodiment, the H2-rich stream 128 has a temperature of from about 60 to about 80° C.

Because the partially heated feed stream 220 contains a substantial amount of olefins, the partially quenched hydrotreated intermediate combined stream 238 contains olefins. As such, the partially quenched hydrotreated intermediate combined stream 238 is introduced to the catalyst bed 38 and contacts the hydroprocessing catalyst in the presence of hydrogen at hydrotreating conditions effective to convert olefins to paraffins via hydrogenation to form the hydrotreated effluent 82. Additionally, sulfur and nitrogen are converted to H2S and NH3, respectively. In an exemplary embodiment, the hydrotreated effluent 82 is enriched with paraffins and further comprises H2S, NH3, naphthenes, and aromatics. In an exemplary embodiment the hydrotreating conditions include a temperature of from about 270 to about 350° C. and the hydrotreated effluent 82 has a temperature of from about 340 to about 390° C. As discussed above, the hydrotreated effluent 82 may be process further downstream, such as, for example, to recover paraffins and remove H2S and NH3 from the hydrotreated effluent 82.

Accordingly, apparatuses and methods for hydrotreating coker kerosene have been described. The exemplary embodiments taught herein provide a feed that comprises coker kerosene and optionally straight run kerosene. The feed is split into first and second feed streams. The first feed stream is heated to form a heated first feed stream. The second feed stream is partially heated to form a partially heated second feed stream. The heated first feed stream is introduced to a hydrotreating reactor and contact contacts a first hydrotreating catalyst to form a first hydrotreated intermediate stream. The partially heated second feed stream is introduced to the hydrotreating reactor and is combined with the first hydrotreated intermediate stream to form a partially quenched first hydrotreated intermediate combined stream. The partially quenched first hydrotreated intermediate combined stream is contacted with a second hydrotreating catalyst in the hydrotreating reactor to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

While at least one exemplary embodiment has been presented in the foregoing detailed description of the disclosure, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration of the disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment of the disclosure. It being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the disclosure as set forth in the appended claims.

Claims

1. A method for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream, the method comprising the steps of:

splitting a feed comprising coker kerosene or other thermally or catalytically cracked hydrocarbon stream and optionally straight run kerosene into a first feed stream and a second feed stream;
heating the first feed stream to form a heated first feed stream;
partially heating the second feed stream to form a partially heated second feed stream that is at a first lower temperature than the heated first feed stream;
contacting the heated first feed stream with a first hydrotreating catalyst in the presence of hydrogen at first hydrotreating conditions effective to form a first hydrotreated intermediate stream;
combining the first hydrotreated intermediate stream with the partially heated second feed stream to form a partially quenched first hydrotreated intermediate combined stream; and
contacting the partially quenched first hydrotreated intermediate combined stream with a second hydrotreating catalyst in the presence of hydrogen at second hydrotreating conditions effective to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

2. The method of claim 1, wherein the step of heating comprises forming the heated first feed stream having a temperature of from about 270 to about 310° C.

3. The method of claim 1, wherein the step of partially heating comprises forming the partially heated second feed stream having a temperature of from about 220 to about 260° C.

4. The method of claim 1, wherein the step of contacting the heated first feed stream comprises contacting the heated first feed stream with the first hydrotreating catalyst at the first hydrotreating conditions that include a temperature of from about 270 to about 350° C.

5. The method of claim 1, wherein the step of contacting the heated first feed stream comprises forming the first hydrotreated intermediate stream having a temperature of from about 340 to about 390° C.

6. The method of claim 1, wherein the step of combining comprises forming the partially quenched first hydrotreated intermediate combined stream having a temperature of from about 270 to about 310° C.

7. The method of claim 1, wherein the step of contacting the partially quenched first hydrotreated intermediate combined stream comprises contacting the partially quenched first hydrotreated intermediate combined stream with the second hydrotreating catalyst at the second hydrotreating conditions that include a temperature of from about 270 to about 350° C.

8. The method of claim 1, wherein the step of combining comprises combining a H2-rich stream with the first hydrotreated intermediate stream and the partially heated second feed stream to form the partially quenched first hydrotreated intermediate combined stream.

9. The method of claim 8, wherein the step of combining comprises combining the H2-rich stream that has a temperature of from about 60 to about 80° C. with the first hydrotreated intermediate stream and the partially heated second feed stream.

10. The method of claim 1, wherein the step of heating comprises:

partially heating the first feed stream in a heat exchanger section to form a partially heated first feed stream; and
heating the partially heated first feed stream in a heater to form the heated first feed stream.

11. The method of claim 10, wherein the step of heating comprises forming the partially heated first feed stream having a temperature of from about 220 to about 260° C.

12. The method of claim 1, wherein the feed is coker kerosene and the step of splitting comprises splitting the feed into a first coker kerosene feed stream as the first feed stream and a second coker kerosene feed stream as the second feed stream.

13. The method of claim 1, wherein the step of splitting comprises splitting the feed into the first feed stream, the second feed stream, a third feed stream, and a fourth feed stream, wherein the step of contacting the partially quenched first hydrotreated intermediate combined stream comprises contacting the partially quenched first hydrotreated intermediate combined stream with the second hydrotreating catalyst to form a second hydrotreated intermediate stream, and wherein the method further comprises the steps of:

heating the third feed stream to form a heated third feed stream;
partially heating the fourth feed stream to form a partially heated fourth feed stream that is at a second lower temperature than the heated third feed stream;
combining the second hydrotreated intermediate stream with the heated third feed stream to form a second hydrotreated intermediate combined stream;
contacting the second hydrotreated intermediate combined stream with a third hydrotreating catalyst in the presence of hydrogen at third hydrotreating conditions effective to form a third hydrotreated intermediate stream;
combining the third hydrotreated intermediate stream with the partially heated fourth feed stream to form a partially quenched third hydrotreated intermediate combined stream; and
contacting the partially quenched third hydrotreated intermediate combined stream with a fourth hydrotreating catalyst in the presence of hydrogen at fourth hydrotreating conditions effective to further hydrotreat the partially quenched third hydrotreated intermediate combined stream.

14. The method of claim 13, wherein the step of contacting the partially quenched third hydrotreated intermediate combined stream comprises contacting the partially quenched third hydrotreated intermediate combined stream with the fourth hydrotreating catalyst to form a hydrotreated effluent, and wherein the step of partially heating the second feed stream comprises indirect heat exchanging from a first portion of the hydrotreated effluent to the second feed stream to form the partially heated second feed stream, and wherein the step of partially heating the fourth feed stream comprises indirect heat exchanging from a second portion of the hydrotreated effluent to the fourth feed stream to form the partially heated fourth feed stream.

15. A method for hydrotreating coker kerosene, the method comprising the steps of:

heating a first straight run kerosene feed stream to form a heated first straight run kerosene feed stream;
partially heating a first coker kerosene feed stream to form a partially heated first coker kerosene feed stream that is at a first lower temperature than the heated first straight run kerosene feed stream;
introducing the heated first straight run kerosene feed stream to a first catalyst bed that contains a first hydrotreating catalyst in the presence of hydrogen and that is operating at first hydrotreating conditions effective to form a first hydrotreated intermediate stream;
combining the first hydrotreated intermediate stream with the partially heated first coker kerosene feed stream to form a partially quenched first hydrotreated intermediate combined stream; and
introducing the partially quenched first hydrotreated intermediate combined stream to a second catalyst bed that contains a second hydrotreating catalyst in the presence of hydrogen and that is operating at second hydrotreating conditions effective to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.

16. The method of claim 15, wherein the step of introducing the partially quenched first hydrotreated intermediate combined stream comprises contacting the partially quenched first hydrotreated intermediate combined stream with the second hydrotreating catalyst to form a second hydrotreated intermediate stream, and wherein the method further comprises the steps of:

splitting a straight run kerosene feed into the first straight run kerosene feed stream and a second straight run kerosene feed stream;
splitting a coker kerosene feed into the first coker kerosene feed stream and a second coker kerosene feed stream;
heating the second straight run kerosene feed stream to form a heated second straight run kerosene feed stream;
partially heating the second coker kerosene feed stream to form a partially heated second coker kerosene feed stream that is at a second lower temperature than the heated second straight run kerosene feed stream;
combining the second hydrotreated intermediate stream with the heated second straight run kerosene feed stream to form a second hydrotreated intermediate combined stream;
introducing the second hydrotreated intermediate combined stream to a third catalyst bed that contains a third hydrotreating catalyst in the presence of hydrogen and that is operating at third hydrotreating conditions effective to form a third hydrotreated intermediate stream;
combining the third hydrotreated intermediate stream with the partially heated second coker kerosene feed stream to form a partially quenched third hydrotreated intermediate combined stream; and
introducing the partially quenched third hydrotreated intermediate combined stream to a fourth catalyst bed that contains a fourth hydrotreating catalyst in the presence of hydrogen and that is operating at fourth hydrotreating conditions effective to further hydrotreat the partially quenched third hydrotreated intermediate combined stream.

17. The method of claim 16, wherein the step of heating the first straight run kerosene feed stream comprises:

partially heating the first straight run kerosene feed stream to form a partially heated first straight run kerosene feed stream; and
heating the partially heated first straight run kerosene feed stream to form the heated first straight run kerosene feed stream, and wherein the step of heating the second straight run kerosene feed stream comprises:
partially heating the second straight run kerosene feed stream to form a partially heated second straight run kerosene feed stream; and
heating the partially heated second straight run kerosene feed stream to form the heated second straight run kerosene feed stream.

18. The method of claim 17, wherein the step of introducing the partially quenched third hydrotreated intermediate combined stream comprises contacting the partially quenched third hydrotreated intermediate combined stream with the fourth hydrotreating catalyst to form a hydrotreated effluent, wherein the step of partially heating the first coker kerosene feed stream comprises indirect heat exchanging from a first portion of the hydrotreated effluent to the first coker kerosene feed stream to form the partially heated first coker kerosene feed stream, wherein the step of partially heating the second coker kerosene feed stream comprises indirect heat exchanging from a second portion of the hydrotreated effluent to the second coker kerosene feed stream to form the partially heated second coker kerosene feed stream, wherein the step of partially heating the first straight run kerosene feed stream comprises indirect heat exchanging from a third portion of the hydrotreated effluent to the first straight run kerosene feed stream to form the partially heated first straight run kerosene feed stream, and wherein the step of partially heating the second straight run kerosene feed stream comprises indirect heat exchanging from a fourth portion of the hydrotreated effluent to the second straight run kerosene feed stream to form the partially heated second straight run kerosene feed stream.

19. The method of claim 15, wherein the step of combining comprises combining a H2-rich stream with the first hydrotreated intermediate stream and the partially heated first coker kerosene feed stream to form the partially quenched first hydrotreated intermediate combined stream, and wherein the H2-rich stream is at a third lower temperature than the first hydrotreated intermediate stream.

20. An apparatus for hydrotreating coker kerosene or other thermally or catalytically cracked hydrocarbon stream, the apparatus comprising:

a fluid circuit configured to split a feed comprising coker kerosene or other thermally or catalytically cracked hydrocarbon stream and optionally straight run kerosene into a first feed stream and a second feed stream;
a heater configured to receive and heat the first feed stream to form a heated first feed stream;
a heat exchanger configured to receive and partially heat the second feed stream to form a partially heated second feed stream that is at a lower temperature than the heated first feed stream; and
a hydrotreating reactor configured to receive and hydrotreat the heated first feed stream and the partially heated second feed stream to form a hydrotreated effluent, wherein the hydrotreating reactor comprises: a first catalyst bed containing a first hydrotreating catalyst and configured to receive the heated first feed stream for contact with the first hydrotreating catalyst in the presence of hydrogen at first hydrotreating conditions effective to form a first hydrotreated intermediate stream, wherein the hydrotreating reactor is configured to combine the first hydrotreated intermediate stream with the partially heated second feed stream to form a partially quenched first hydrotreated intermediate combined stream; and a second catalyst bed containing a second hydrotreating catalyst and configured to receive the partially quenched first hydrotreated intermediate combined stream for contact with the second hydrotreating catalyst in the presence of hydrogen at second hydrotreating conditions effective to further hydrotreat the partially quenched first hydrotreated intermediate combined stream.
Patent History
Publication number: 20150129461
Type: Application
Filed: Nov 14, 2013
Publication Date: May 14, 2015
Applicant: UOP LLC (Des Plaines, IL)
Inventor: Soumendra Mohan Banerjee (New Delhi)
Application Number: 14/080,269
Classifications
Current U.S. Class: With Hydrogen (208/89); Refining (208/97); Catalytic (208/143); With Hydrogen (208/264); Combined (422/187)
International Classification: C10G 65/04 (20060101);