Fixed bed residual oil hydrogenation catalyst full-cycle vulcanization system and full-cycle vulcanization method thereof

Abstract

The invention discloses a fixed bed residual oil hydrogenation catalyst full-cycle vulcanization system and a full-cycle vulcanization method thereof. A vulcanizing agent pipeline is connected with a first heating furnace; the first heating furnace is sequentially connected with a demetallization catalyst reactor with a demetallization catalyst and a desulfurized nitrogen and carbon residue catalyst reactor with a desulfurization catalyst, a denitrification catalyst and a carbon residue removal catalyst through pipelines, and the demetallization catalyst reactor and the desulfurized nitrogen and carbon residue catalyst reactor are further connected with a transition reactor; the desulfurization nitrogen and carbon residue catalyst reactor is connected with a cold and hot high-pressure separation system, the cold and hot high-pressure separation system is connected with a stripping tower, the stripping tower is connected with a second heating furnace, the outlet end of the second heating furnace is connected with a fractionating tower, and the fractionating tower is connected with pipelines for conveying naphtha, diesel oil, heavy dirty oil and hydrogenated residual oil through pipelines. The method has the technical characteristics of being capable of reducing the consumption of start-up wax oil, reducing the output of heavy dirty oil in a high-temperature vulcanization stage, reducing the heavy dirty oil treatment load of a whole plant, reducing dirty oil recycling energy consumption and the like.

Description

Technical Field

[0001] The present invention relates to a full-circulation sulfurization system and a full-circulation sulfurization method, and more specifically, to a fixed-bed residue oil hydrogenation catalyst full-circulation sulfurization system and a full-circulation sulfurization method, and belongs to the field of petrochemical industry. Background Art

[0002] During the startup of a fixed-bed residue oil hydrotreating unit, the catalyst is usually vulcanized using a wet vulcanization process in the reactor. The conventional wet vulcanization process is divided into two stages: diesel circulating vulcanization and low-temperature vulcanization, and wax oil one-pass vulcanization and high-temperature vulcanization. In the wax oil one-pass vulcanization stage, a large amount of sulfurized wax oil needs to be prepared, and a large amount of sulfurized heavy waste oil will also be produced. The sulfurized heavy waste oil needs to be re-entered into the atmospheric and vacuum unit or coking unit for recycling, which not only increases the processing load of the waste oil system of the entire plant, but also increases the crude oil processing cost, resulting in a high startup cost. Developing a catalyst vulcanization method that reduces the output of heavy waste oil has very considerable economic benefits for reducing the startup cost of residue oil hydrotreating units. Summary of the invention

[0003] In order to solve the above-mentioned problems in the prior art, the present invention provides a fixed-bed residual oil hydrogenation catalyst full-circulation sulfurization system and a full-circulation sulfurization method thereof, which have the technical characteristics of being able to reduce the consumption of wax oil at start-up, reduce the amount of heavy oil produced in the high-temperature sulfurization stage, reduce the heavy oil treatment load of the whole plant, and reduce the energy consumption of waste oil recycling by changing the wax oil once-through sulfurization process to a circulation sulfurization process without affecting the catalyst sulfurization effect.

[0004] In order to achieve the above object, the present invention is implemented by the following technical solutions:

[0005] The present invention discloses a fixed bed residual oil hydrogenation catalyst full circulation sulfurization system, comprising a sulfurizing agent pipeline and a sulfurized oil pipeline connected to the sulfurizing agent pipeline, wherein the sulfurizing agent pipeline is connected to a No. 1 heating furnace, and the No. 1 heating furnace is sequentially connected to a demetallization catalyst reactor with a demetallization catalyst and a desulfurization and nitrogenation carbon residue catalyst reactor with a desulfurization catalyst, a denitrification catalyst, and a carbon removal catalyst through pipelines, the demetallization catalyst reactor and the desulfurization and nitrogenation carbon residue catalyst reactor are also connected to a transition reactor, the desulfurization and nitrogenation carbon residue catalyst reactor is connected to a cold and hot high separation system, the cold and hot high separation system is connected to a stripping tower, the stripping tower is connected to a No. 2 heating furnace, the outlet end of the No. 2 heating furnace is connected to a fractionation tower, and the fractionation tower is respectively connected to a No. 1 pipeline for conveying naphtha, a No. 2 pipeline for conveying diesel, a No. 3 pipeline for conveying heavy dirty oil, and a No. 4 pipeline for conveying hydrogenated residual oil through pipelines;

[0006] The hot and cold high-pressure separator system includes a hot high-pressure separator, a hot low-pressure separator, a cold high-pressure separator, and a cold low-pressure separator. The hot high-pressure separator is connected to a desulfurization and nitrogen residue carbon catalyst reactor. The top of the hot high-pressure separator is connected to the inlet of the cold high-pressure separator through a pipeline. The outlet of the cold high-pressure separator is divided into two branches through a pipeline, one of which is connected to the top of the hot low-pressure separator, and the other is connected to the inlet of the cold low-pressure separator through a pipeline. The outlet of the cold low-pressure separator is connected to a stripping tower through a pipeline, and the bottom of the hot high-pressure separator is connected to the hot low-pressure separator through a pipeline, and the bottom of the hot low-pressure separator is connected to the stripping tower through a pipeline; the cold high-pressure separator 15 is connected to a circulating hydrogen desulfurization tower, and the circulating hydrogen desulfurization tower is connected to a circulating compressor for conveying hydrogen through a pipeline, and the circulating compressor is connected to the sulfiding agent pipeline through a pipeline.

[0007] The present invention provides a full-circulation sulfurization method of a fixed-bed residue oil hydrogenation catalyst full-circulation sulfurization system, the method comprising the following steps:

[0008] Step 1) loading catalyst into each reactor, completing gas replacement and catalyst drying in sequence, and starting catalyst presulfurization;

[0009] Step 2) introducing the start-up diesel into the system to wet the catalyst, heating it to 170°C after the wetting is completed, sending the sulfided waste oil out to the heavy waste oil circulation into the sulfiding agent pipeline process, and continuing to heat it up, and starting to inject the sulfiding agent after the temperature reaches 215°C;

[0010] After the sulfidation temperature wave passes through all reactor catalyst beds, the temperature is raised and maintained at 230°C for low-temperature sulfidation. The concentration of hydrogen sulfide in the circulating hydrogen after desulfurization is analyzed. When the H2S concentration in the circulating hydrogen is > 0.5 vol% at two consecutive points of analysis, the purity of the circulating hydrogen is > 60%, and no water is generated in the cold high fraction, the low-temperature sulfidation is completed;

[0011] After low-temperature vulcanization is completed, the temperature continues to rise. When it reaches 245°C, the wax oil is switched to start replacement. During the replacement process, the sulfurized diesel is transported to the discharged heavy waste oil. The sulfur injection amount is adjusted to control the H2S concentration in the circulating hydrogen to 0.5-1.0 vol%. When the H2S concentration exceeds 1.0 vol%, the injection of the vulcanizing agent is stopped;

[0012] When the total amount of wax oil introduced into the system reaches the storage capacity of the reaction system, it is confirmed that all the sulfurized diesel in the system is switched to sulfurized wax oil, and the full circulation process is changed. The H2S concentration in the circulating hydrogen is controlled in the range of 0.5-1.0 vol% during the circulation process, and the sulfiding agent is supplemented according to the analysis of the circulating hydrogen;

[0013] Step 3) Continue to heat up to 320°C. As the temperature rises, the catalyst has initial activity and reacts slightly, causing the circulating oil to become lighter and decrease. Fresh start-up wax oil is added to control the circulating oil volume to not less than 80% of the designed feed volume, and maintain the H2S concentration in the circulating hydrogen in the range of 0.5-1.0 vol%;

[0014] Step 4) Maintain high temperature sulfurization at 320°C for more than 4 hours, maintain the temperature of all reactors above 300°C, and maintain the H2S concentration in the circulating hydrogen in the range of 0.5-1.0 vol% for more than 4 hours, and the high temperature sulfurization is completed, and the catalyst sulfurization process is completed.

[0015] Beneficial effects: 1. The fixed-bed residue oil hydrogenation catalyst sulfurization process is optimized. By changing the wax oil once-through sulfurization process to a circulating sulfurization process, the wax oil consumption at start-up is reduced without affecting the catalyst sulfurization effect, and the amount of heavy oil produced in the high-temperature sulfurization stage is reduced, thereby reducing the heavy oil treatment load of the entire plant and the energy consumption of waste oil recycling.

[0016] 2. This process converts the wax oil into a circulating sulfidation process. The H2S concentration analysis in the circulating hydrogen can be used to quantitatively calculate the sulfiding agent injection demand. Compared with the conventional process in which the H2S concentration is usually controlled by adjusting the amount of lean amine liquid, this reduces material and energy consumption during the start-up process.

[0017] 3. The circulation process is adopted in the high-temperature vulcanization stage. By controlling the appropriate temperature of the circulating vulcanizing oil, the heating rate during the vulcanization process is increased and the start-up schedule is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the overall structure of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited to the following embodiments.

[0020] Purpose of the present invention:

[0021] 1. Optimize the wet sulfurization process operation of the fixed-bed residue oil hydrotreating unit. On the basis of the traditional sulfurization process, by changing the wax oil once-through sulfurization process to wax oil circulating sulfurization, it can reduce the demand for wax oil at the start-up and reduce the amount of heavy oil produced.

[0022] 2. The wax oil once-through sulfidation stage is changed to wax oil circulating sulfidation. The hydrogen sulfide content in the system is maintained by adding sulfiding agent. While maintaining sufficient feed volume and maintaining uniform distribution of materials in the reactor, the amount of sulfiding agent can be accurately controlled, reducing the amount of lean amine liquid for recovering excess hydrogen sulfide and reducing material and energy consumption during the start-up process.

[0023] 3. By adopting circulating vulcanization operation and controlling the circulating oil temperature, the heating rate during the vulcanization process can be increased, the vulcanization stage time can be shortened, the consumption of fuel gas can be reduced, and the start-up speed can be accelerated.

[0024] like Figure 1 The present invention shows a specific embodiment of a fixed-bed residual oil hydrogenation catalyst full-circulation sulfurization system and a full-circulation sulfurization method thereof. The embodiment is a fixed-bed residual oil hydrogenation catalyst full-circulation sulfurization system and a full-circulation sulfurization method thereof, comprising a sulfurizing agent pipeline 1 and a sulfurized oil pipeline 2 connected to the sulfurizing agent pipeline 1, wherein the sulfurizing agent pipeline 1 is connected to a first heating furnace 3, and the first heating furnace 3 is sequentially connected to a demetallization catalyst reactor 4 with a demetallization catalyst and a desulfurization catalyst, a denitrification catalyst, and a decarbonization catalyst through pipelines. Reactor 5, the demetallization catalyst reactor 4 and the desulfurization and denitrification carbon residue catalyst reactor 5 are also connected to a transition reactor 6, the desulfurization and denitrification carbon residue catalyst reactor 5 is connected to a cold and hot high separation system, the cold and hot high separation system is connected to a stripping tower 17, the stripping tower 17 is connected to a No. 2 heating furnace 7, the outlet end of the No. 2 heating furnace 7 is connected to a fractionation tower 8, and the fractionation tower 8 is respectively connected to a No. 1 pipeline 9 for conveying naphtha, a No. 2 pipeline 10 for conveying diesel, a No. 3 pipeline 11 for conveying heavy waste oil, and a No. 4 pipeline 12 for conveying hydrogenated residual oil through pipelines;

[0025] The hot and cold high pressure separator system comprises a hot high pressure separator 13, a hot low pressure separator 14, a cold high pressure separator 15 and a cold low pressure separator 16. The hot high pressure separator 13 is connected to a desulfurization and nitrogen removal carbon residue catalyst reactor 5. The top of the hot high pressure separator 13 is connected to the inlet of the cold high pressure separator 15 through a pipeline. The outlet of the cold high pressure separator 15 is divided into two branches through a pipeline, one of which is connected to the top of the hot low pressure separator 14, and the other is connected to the inlet of the cold low pressure separator 16 through a pipeline. The outlet of the cold low pressure separator 16 is connected to a stripping tower 17 through a pipeline. The bottom of the hot high pressure separator 13 is connected to the hot low pressure separator 14 through a pipeline, and the bottom of the hot low pressure separator 14 is connected to the stripping tower 17 through a pipeline. The cold high pressure separator 15 is connected to a circulating hydrogen desulfurization tower 18, and the circulating hydrogen desulfurization tower 18 is connected to a circulating compressor for conveying hydrogen through a pipeline, and the circulating compressor is connected to the sulfiding agent pipeline 1 through a pipeline.

[0026] The invention is applicable to a fixed-bed residual oil hydrogenation catalyst wet sulfurization process, belongs to the field of petrochemical industry, has a very obvious optimization of the start-up process of the residual oil hydrogenation device, has a great improvement in start-up time, start-up materials, and start-up energy consumption, and has a very broad application prospect.

[0027] The role of residue oil hydrogenation catalyst and sulfidation:

[0028] Residue oil hydrogenation catalysts are mainly divided into demetallization, desulfurization, denitrogenation and carbon removal. Catalytically active residue oil hydrogenation catalysts are molybdenum sulfide, nickel sulfide, cobalt sulfide and tungsten sulfide. Different metal sulfides have different functions. Due to the preparation process and storage stability, hydrogenation catalysts are generally in an oxidized state when leaving the factory. Therefore, the catalyst must be sulfurized when the device is started to make it have the catalytic activity required for production. The selection of sulfiding agents is based on comprehensive considerations of economy and safety. Dimethyl disulfide DMDS, an organic sulfide with high sulfur content and low toxicity, is generally selected. In the low-temperature sulfidation stage, due to the low sulfur content in diesel, the sulfur required for the sulfidation process must be provided by the sulfiding agent; in the high-temperature sulfidation stage, since the catalyst has already had some activity and the sulfur content in the wax oil is high, the supplementary sulfiding agent can be reduced or even stopped if the hydrogen sulfide content in the circulating hydrogen meets the requirements.

[0029] The design idea of ​​the catalyst presulfurization process of the present invention is as follows:

[0030] 1. A certain amount of vulcanizing agent is injected into the sulfided oil. After the sulfided oil is pressurized, it is mixed with the circulating hydrogen to increase the temperature and then passes through the catalyst beds of each reactor in turn to wet and sulfide the catalyst.

[0031] 2. The sulfurized oil after sulfurization is separated into gas and liquid in hot and cold high and low separations in turn. The gas phase passes through the cold high separation and circulating hydrogen desulfurization tower, and is compressed by the circulating hydrogen compressor and then returned for circulation;

[0032] 3. When the one-pass process is adopted, the sulfide-generated oil passes through the hot high and low separations in turn and enters the desulfurization hydrogen stripping tower and the distillation tower, and is sent to the heavy oil tank area through the heavy oil line on the bottom oil pipeline of the distillation tower;

[0033] 4. When the circulation process is adopted, the sulfide-generated oil is circulated through the long circulation process on the distillation tower bottom oil pipeline and returned to the reaction feed line.

[0034] The specific contents of the catalyst presulfurization process of the present invention are as follows:

[0035] The present invention provides a full-circulation sulfurization method of a fixed-bed residue oil hydrogenation catalyst full-circulation sulfurization system, the method comprising the following steps:

[0036] Step 1) loading catalyst into each reactor, completing gas replacement and catalyst drying in sequence, and starting catalyst presulfurization;

[0037] Step 2) introducing the start-up diesel into the system to wet the catalyst, heating it to 170°C after the wetting is completed, sending the sulfided waste oil to the heavy waste oil circulation into the sulfiding agent pipeline 11 process, and continuing to heat it up, and starting to inject the sulfiding agent after the temperature reaches 215°C;

[0038] After the sulfidation temperature wave passes through all reactor catalyst beds, the temperature is raised and maintained at 230°C for low-temperature sulfidation. The concentration of hydrogen sulfide in the circulating hydrogen after desulfurization is analyzed. When the H2S concentration in the circulating hydrogen is > 0.5 vol% at two consecutive points of analysis, the purity of the circulating hydrogen is > 60%, and no water is generated in the cold high fraction, the low-temperature sulfidation is completed;

[0039] After low-temperature vulcanization is completed, the temperature continues to rise. When it reaches 245°C, the wax oil is switched to start replacement. During the replacement process, the sulfurized diesel is transported to the discharged heavy waste oil. The sulfur injection amount is adjusted to control the H2S concentration in the circulating hydrogen to 0.5-1.0 vol%. When the H2S concentration exceeds 1.0 vol%, the injection of the vulcanizing agent is stopped;

[0040] When the total amount of wax oil introduced into the system reaches the storage capacity of the reaction system, it is confirmed that all the sulfurized diesel in the system is switched to sulfurized wax oil, and the full circulation process is changed. The H2S concentration in the circulating hydrogen is controlled in the range of 0.5-1.0 vol% during the circulation process, and the sulfiding agent is supplemented according to the analysis of the circulating hydrogen;

[0041] Step 3) Continue to heat up to 320°C. As the temperature rises, the catalyst has initial activity and reacts slightly, causing the circulating oil to become lighter and decrease. Fresh start-up wax oil is added to control the circulating oil volume to not less than 80% of the designed feed volume, and maintain the H2S concentration in the circulating hydrogen in the range of 0.5-1.0 vol%;

[0042] Step 4) Maintain high temperature sulfurization at 320°C for more than 4 hours, maintain the temperature of all reactors above 300°C, and maintain the H2S concentration in the circulating hydrogen in the range of 0.5-1.0 vol% for more than 4 hours, and the high temperature sulfurization is completed, and the catalyst sulfurization process is completed.

[0043] The comparison between the catalyst sulfurization operation in the present invention and the conventional sulfurization operation is shown in Table 1 below.

[0044] Table 1 Catalyst sulfidation operation

[0045]

[0046]

[0047] Benefits and advantages

[0048] According to the adjustment of the catalyst sulfidation process operation, the improved process is compared with the conventional sulfidation process operation, which reduces the amount of heavy oil produced overall. The changes in the amount of heavy oil produced after the optimization of the sulfidation operation at each stage are shown in Table 2.

[0049] Table 2 Comparison of the amount of waste oil generated during catalyst sulfidation

[0050]

[0051] Therefore, the high temperature vulcanization process can reduce the generation of heavy oil by 70%-80% by changing the one-time process to cyclic vulcanization. The entire vulcanization process can reduce the generation of heavy oil by about 50%. The vulcanization process can be fine-tuned in accordance with the specific requirements of the catalyst manufacturer to achieve the catalyst vulcanization technical indicators. The adjustment method is simple and easy to operate, while reducing the generation of dirty oil and the economic cost of the vulcanization process without affecting the catalyst vulcanization effect.

[0052] Finally, it should be noted that the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by ordinary technicians in this field should be considered as the protection scope of the present invention.

Claims

1. A fixed bed residue oil hydrogenation catalyst full circulation sulfurization system, Features: The invention comprises a vulcanizing agent pipeline (1) and a vulcanizing oil pipeline (2) connected to the vulcanizing agent pipeline (1), wherein the vulcanizing agent pipeline (1) is connected to a first heating furnace (3), and the first heating furnace (3) is sequentially connected to a demetallizing catalyst reactor (4) with a demetallizing catalyst and a desulfurization and denitrification and decarbonization catalyst reactor (5) with a desulfurization catalyst, a denitrification catalyst, and a decarbonization catalyst through pipelines, and the demetallizing catalyst reactor (4) and the desulfurization and denitrification and decarbonization catalyst reactor (5) are also connected to a transition reactor. The desulfurization and nitrogen removal carbon residue catalyst reactor (5) is connected to a cold and hot high separation system, the cold and hot high separation system is connected to a stripping tower (17), the stripping tower (17) is connected to a No. 2 heating furnace (7), the outlet end of the No. 2 heating furnace (7) is connected to a fractionation tower (8), and the fractionation tower (8) is connected to a No. 1 pipeline (9) for conveying naphtha, a No. 2 pipeline (10) for conveying diesel, a No. 3 pipeline (11) for conveying heavy waste oil, and a No. 4 pipeline (12) for conveying hydrogenated residual oil through pipelines; The hot and cold high pressure separator system comprises a hot high pressure separator (13), a hot low pressure separator (14), a cold high pressure separator (15), and a cold low pressure separator (16). The hot high pressure separator (13) is connected to the desulfurization and nitrogen removal carbon residue catalyst reactor (5). The top of the hot high pressure separator (13) is connected to the inlet of the cold high pressure separator (15) through a pipeline. The outlet of the cold high pressure separator (15) is divided into two branches through a pipeline, one of which is connected to the top of the hot low pressure separator (14), and the other is connected to the outlet of the cold low pressure separator (16) through a pipeline. The cold low-pressure separator (16) is connected to the inlet of the separator (16), the outlet of the cold low-pressure separator (16) is connected to the stripping tower (17) through a pipeline, the bottom of the hot high-pressure separator (13) is connected to the hot low-pressure separator (14) through a pipeline, and the bottom of the hot low-pressure separator (14) is connected to the stripping tower (17) through a pipeline; the cold high-pressure separator (15) is connected to a circulating hydrogen desulfurization tower (18), and the circulating hydrogen desulfurization tower (18) is connected to a circulating compressor for conveying hydrogen through a pipeline, and the circulating compressor is connected to the sulfiding agent pipeline (1) through a pipeline.

2. A full-cycle sulfurization method using a fixed-bed residue oil hydrogenation catalyst full-cycle sulfurization system according to claim 1, Features The method comprises the following steps: Step 1) loading catalyst into each reactor, completing gas replacement and catalyst drying in sequence, and starting catalyst presulfurization; Step 2) Introduce the start-up diesel into the system to wet the catalyst, and after the wetting is completed, heat it up to 170°C, send the sulfided waste oil outward, and the heavy waste oil circulates into the sulfidizing agent pipeline (1) (1) process, continue to heat it up, and start injecting the sulfidizing agent after the temperature reaches 215°C; After the sulfurization temperature wave passes through all the reactor catalyst beds, the temperature is raised and maintained at 230°C for low-temperature sulfurization. The concentration of hydrogen sulfide in the circulating hydrogen after desulfurization is analyzed. 2 When the S concentration is > 0.5 vol% (circulating hydrogen purity > 60%) at two consecutive analysis points and no water is generated in the cold high fraction, low-temperature sulfidation is completed; After low-temperature vulcanization is completed, the temperature continues to rise. When it reaches 245°C, the wax oil is switched to start replacement. During the replacement process, the sulfurized diesel is transported to the discharged heavy waste oil. The sulfur injection amount is adjusted to control the H in the circulating hydrogen. 2 When the S concentration is between 0.5 and 1.0 vol%, 2 When the S concentration exceeds 1.0 vol%, stop injecting the vulcanizing agent; When the total amount of wax oil introduced into the system reaches the storage capacity of the reaction system, it is confirmed that all the sulfurized diesel in the system has been switched to sulfurized wax oil, and the full circulation process is changed. The circulation process controls the H in the circulating hydrogen. 2 The S concentration is in the range of 0.5 to 1.0 vol%, and the sulfiding agent is supplemented according to the circulating hydrogen analysis; Step 3) Continue to heat up to 320°C. As the temperature rises, the catalyst has initial activity and reacts slightly, causing the circulating oil to become lighter and decrease. Fresh wax oil is added to control the circulating oil volume to not less than 80% of the designed feed volume, maintaining the H content in the circulating hydrogen. 2 S concentration is in the range of 0.5 to 1.0 vol%; Step 4) Maintain high temperature sulfurization at 320°C for more than 4 hours, maintain the temperature of all reactors above 300°C, and keep H 2 The sulfur concentration is maintained in the range of 0.5-1.0 vol% for more than 4 hours, and the high temperature sulfurization is completed, and the catalyst sulfurization process is completed.

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