A start-up method for a shale oil hydrotreating unit

Abstract

This invention discloses a start-up method for a shale oil hydrotreating unit. After completing catalyst loading, airtightness checks, and establishing the circulating hydrogen system, the hourly volumetric flow rate of circulating hydrogen is controlled to be 100–800 times the total catalyst loading volume. NO gas is injected into the inlet of the hydrorefining reaction zone at a volumetric injection rate of 5%–20% of the circulating hydrogen flow rate. The reactor inlet temperature is raised to 170–250°C. When the NO2 volume fraction in the circulating hydrogen reaches 10%–30%, NO gas injection is stopped. Then, the catalyst in the hydrorefining reaction zone is sequentially subjected to hydrogen replacement and sulfidation. After sulfidation, feedstock oil is introduced. Using this method to start up a shale oil hydrotreating unit achieves the goals of improving catalyst stability and extending the unit's operating cycle.

Description

Technical Field

[0001] This invention relates to the field of shale oil hydrogenation technology, and particularly to a method for starting up a shale oil hydrogenation unit. Background Technology

[0002] China possesses abundant shale oil resources, with recoverable reserves of approximately 5 billion tons, ranking third globally after Russia and the United States. As China becomes the world's second-largest oil consumer, with its crude oil dependence exceeding 70%, shale oil is poised to become an important alternative resource. Since becoming a net oil importer again in 1993, China's oil consumption and demand have increased dramatically, while its crude oil production has grown slowly, leading to a widening supply-demand gap year by year. According to data from the National Energy Administration, China's oil dependence reached 50% in 2007, and without the development of new alternative energy sources, this figure is projected to reach 70% by 2030. This will reach the internationally recognized energy security threshold, making China's energy security situation extremely serious. Therefore, the comprehensive utilization and development of natural oil substitutes, such as coal tar and shale oil resources, is of great significance. Fortunately, China has very rich shale oil resources awaiting development, ranking third globally after Canada and the United States, with recoverable reserves of approximately 20 billion tons. From the perspective of national energy system adjustment, the extraction and processing of shale oil is an inevitable trend.

[0003] Shale oil has a much higher oxygen content than natural petroleum, and is low in sulfur and high in nitrogen. Shale oil hydrogenation units operate at high temperatures for extended periods, therefore, the catalyst system must have good stability.

[0004] There are many reports on start-up methods for conventional feedstock hydrotreating units, but few reports on start-up methods for improving catalyst stability in shale oil hydrotreating units.

[0005] CN111378489A discloses a start-up method for a hydrotreating unit. After the unit is sealed, the catalyst inside is heated to induce sulfidation. After sulfidation, the hydrotreating unit is cooled, and feedstock oil is introduced to begin the hydrotreating reaction. The unit uses a sulfidation-type hydrorefining catalyst, and the hydrogen sulfide and ammonia generated during start-up can sulfidate and passivate the subsequent hydrocracking catalyst.

[0006] CN112295575A discloses a method for preparing a hydrogenation catalyst and a method for starting up a hydrogenation unit. This method includes steps of drying, calcining (or not calcining), sulfiding, and passivating the oxidized hydrogenation catalyst, all within the same cavity region. The method involves loading the prepared hydrogenation catalyst into a hydrogenation reactor, introducing hydrogen gas to reduce the catalyst, then introducing feedstock oil, and heating to the reaction temperature to begin oil production. This method can shorten the start-up time of the hydrogenation unit and reduce start-up risks.

[0007] None of the above-mentioned existing technologies have solved the problem that the hydrogenation unit cannot operate stably for a long period of time due to the low concentration of hydrogen sulfide and poor catalyst stability in the low-sulfur shale oil hydrogenation unit. Summary of the Invention

[0008] To address the shortcomings of existing technologies, this invention provides a start-up method for a shale oil hydrotreating unit. This start-up method can improve catalyst stability and extend the unit's operating cycle.

[0009] This invention provides a startup method for a shale oil hydrotreating unit, comprising: after completing catalyst loading, airtightness inspection, and establishing a circulating hydrogen system for the shale oil hydrotreating unit, controlling the hourly volumetric flow rate of circulating hydrogen to be 100 to 800 times the total catalyst loading volume, injecting NO gas into the inlet of the hydrorefining reaction zone at a volumetric injection rate of 5% to 20% of the circulating hydrogen volumetric flow rate, raising the reactor inlet temperature to 170 to 250°C, stopping the injection of NO gas when the NO2 volume fraction in the circulating hydrogen is 10% to 30%, and then sequentially performing hydrogen replacement and sulfidation on the catalyst in the hydrorefining reaction zone, followed by the introduction of feedstock oil after sulfidation.

[0010] Furthermore, the NO volumetric injection rate is 5% to 20% of the circulating hydrogen volumetric flow rate, wherein both the NO volumetric injection rate and the circulating hydrogen volumetric flow rate are measured in hours.

[0011] Furthermore, the airtightness check and the establishment of the circulating hydrogen system are carried out using conventional methods in the art, and there are no particular limitations in this invention. After the airtightness check and the establishment of the circulating hydrogen system, the high-pressure component is controlled at the design pressure, typically 4.0–10.0 MPa.

[0012] Furthermore, the hydrogen replacement is completed when the hydrogen gas fraction in the circulating hydrogen reaches 96%–99%. This hydrogen replacement process can involve introducing fresh hydrogen into the circulating hydrogen system, or introducing a shale oil hydrogenation device at the inlet of the hydrorefining reaction zone to replace the gas in the system, until the hydrogen gas fraction in the circulating hydrogen reaches 96%–99%, at which point the hydrogen replacement is complete.

[0013] Furthermore, before hydrogen replacement, the inlet temperature of the hydrorefining reaction zone can be lowered to 150–180°C before hydrogen replacement is performed.

[0014] Furthermore, the vulcanization process employs either wet vulcanization or dry vulcanization, preferably dry vulcanization.

[0015] Furthermore, the dry sulfidation includes a first sulfidation stage and a second sulfidation stage. In the first sulfidation stage, the inlet temperature of the hydrorefining reaction zone is increased to a first constant temperature of 220-260°C at a heating rate of 2-8°C / h, and then held at the first constant temperature for 4-10 hours. During the first sulfidation stage, the mass concentration of hydrogen sulfide in the circulating hydrogen is maintained at 2000-6000 ppm. In the second sulfidation stage, the inlet temperature of the hydrorefining reaction zone is increased to a second constant temperature of 340-400°C at a heating rate of 3-8°C / h, and then held at the second constant temperature for 4-10 hours. During the second sulfidation stage, the mass concentration of hydrogen sulfide in the circulating hydrogen is controlled to reach 12000-25000 ppm.

[0016] Furthermore, in the drying and sulfidation process, before entering the first sulfidation stage, a sulfiding agent is gradually injected into the shale oil hydrotreating unit, and the temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed of the hydrorefining reaction zone until hydrogen sulfide penetrates the entire catalyst bed. Preferably, the conditions for hydrogen sulfide to penetrate the entire catalyst bed are as follows: the mass concentration of hydrogen sulfide in the circulating hydrogen reaches more than 1000 ppm, and more preferably 1000 to 8000 ppm.

[0017] Further, the hydrorefining reaction zone is filled with a hydrorefining catalyst. The hydrorefining catalyst typically includes a hydrorefining active component, a support, and a binder. The hydrorefining active metal includes at least one of Group VIB metals (such as tungsten and / or molybdenum) and Group VIII metals (such as nickel and / or cobalt); the support includes at least one of alumina, silica, and amorphous silica-alumina; the binder is typically alumina or silica. Based on the weight of the catalyst, the content of the Group VIB metal oxide is 15 wt% to 35 wt%, preferably 18 wt% to 25 wt%, and the content of the Group VIII metal oxide is 2 wt% to 10 wt%, preferably 3 wt% to 8 wt%. The hydrorefining catalyst can be prepared according to existing methods, or industrial catalysts such as FF-36, FF-46, FF-56, and FF-66 developed by the Dalian Petrochemical Research Institute can be used.

[0018] Furthermore, the vulcanizing agent is a commonly used industrial vulcanizing agent and / or an environmentally friendly vulcanizing agent. Commonly used industrial vulcanizing agents include at least one of the following: dimethyl disulfide (DMDS), carbon disulfide (CS2), etc.

[0019] Furthermore, the feedstock oil is selected from shale oil, and the feedstock oil has an initial boiling point of 50-100℃, a final boiling point of 350-450℃, a sulfur content of less than 8000ppm, and a nitrogen content of 14000-30000ppm.

[0020] Furthermore, the specific operation of introducing the feedstock oil is as follows: the inlet temperature of the hydrorefining reaction zone is reduced to 250-300°C, and the feedstock oil is introduced. The initial introduction amount is 30-50% of the designed processing load. After stabilization, the feedstock oil feed rate is adjusted to 60%-100% of the designed processing load. The reaction temperature is adjusted until the shale oil product quality is qualified.

[0021] Furthermore, during normal production, the reaction conditions in the hydrorefining reaction zone are as follows:

[0022] The reaction pressure is 4.0–10.0 MPa, the hydrorefining reaction temperature is 250–370 °C, and the liquid hourly space velocity (LHSV) during hydrorefining is 0.5–4.0 h⁻¹. -1 Preferably, the reaction pressure is 6.0–8.0 MPa, the hydrorefining reaction temperature is 300–350 °C, and the liquid hourly space velocity (LHSV) is 1.0–2.0 h⁻¹. -1 .

[0023] Furthermore, after the raw material is mixed with hydrogen, it undergoes desulfurization, denitrification, and dearomatization reactions with the catalyst in the hydrorefining reaction zone. The resulting hydrorefined effluent is then separated to obtain shale oil products.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) In the start-up process of this invention, the hydrorefining catalyst is first partially reduced and then sulfided. By flexibly adjusting the sulfidation atmosphere, temperature and time during the start-up process, some of the six-coordinate active metals with high hydrorefining activity but poor stability in the catalyst are reduced to four-coordinate active metals with good stability. This can significantly improve the stability of the catalyst, adapt to low-sulfur shale oil feedstock, extend the operation cycle of the unit, and reduce hydrogen consumption while meeting the product quality requirements, thus saving energy and reducing consumption.

[0026] (2) The start-up process involved in the method of the present invention is simple and controllable, there is no risk of overheating, and the product adjustment time is short. Detailed Implementation

[0027] The following embodiments will further illustrate the starting method provided by the present invention, to compare and demonstrate the effects and advantages of the starting method of the present invention, but this does not limit the present invention.

[0028] In this invention, unless otherwise specified, percentages refer to mass fractions.

[0029] The feedstock oil involved in the following examples is low-sulfur shale oil, and its properties are shown in Table 1. The main physical properties of various catalysts are shown in Table 2. In the examples and comparative examples, the refining reactors are filled with FF-66 hydrorefining catalyst. The main evaluation conditions are shown in Table 3. The evaluation results of the examples are shown in Table 4, and the evaluation results of the comparative examples are shown in Table 5.

[0030] Example 1

[0031] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure fraction is controlled at the design pressure, and the hourly volumetric flow rate of circulating hydrogen is controlled at 300 times the total catalyst loading volume. NO gas is injected into the inlet of the hydrorefining reaction zone at a volumetric injection rate of 10% of the circulating hydrogen volumetric flow rate. The reactor inlet temperature is increased to 200°C, and when the NO2 volume fraction in the circulating hydrogen reaches 18%, the NO gas injection is stopped, and the reactor inlet temperature is reduced to 175°C.

[0032] New hydrogen is introduced into the circulating hydrogen system and introduced into the shale oil hydrogenation unit through the reaction zone to replace the gas in the reaction system. The hydrogen replacement is completed when the hydrogen gas fraction in the circulating hydrogen reaches 98%.

[0033] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 1000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 240°C at a rate of 5°C / h, and constant-temperature sulfidation is carried out for 8 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen is controlled to be maintained at 2000–3000 ppm.

[0034] After the isothermal treatment at 240℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 360℃ at a rate of 6℃ / h, and sulfidation is carried out at this isothermal temperature for 8 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 13,000 and 15,000 ppm.

[0035] After the 360℃ isothermal period, the reactor inlet temperature was reduced to 300℃, and feedstock oil was introduced, with an initial introduction rate of 40% of the designed processing load. After stabilization, the feedstock oil rate was adjusted to 80% of the designed processing load. Subsequently, the refining reaction temperature was adjusted, and the catalyst was evaluated over a long period according to the conditions in Table 3.

[0036] Example 2

[0037] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure fraction is controlled at the design pressure, and the hourly volumetric flow rate of circulating hydrogen is controlled at 400 times the total catalyst loading volume. NO gas is injected into the inlet of the hydrorefining reaction zone at a volumetric injection rate of 15% of the circulating hydrogen volumetric flow rate. The reactor inlet temperature is increased to 210°C, and when the NO2 volume fraction in the circulating hydrogen reaches 25%, the NO gas injection is stopped, and the reactor inlet temperature is reduced to 165°C.

[0038] New hydrogen is introduced into the circulating hydrogen system and introduced into the shale oil hydrogenation unit through the reaction zone to replace the gas in the reaction system. The hydrogen replacement is completed when the hydrogen gas fraction in the circulating hydrogen reaches 98%.

[0039] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 2000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 250°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 6 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 3000–4000 ppm.

[0040] After the isothermal treatment at 250℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 350℃ at a rate of 5℃ / h, and the sulfidation is maintained at this temperature for 8 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 14,000 and 16,000 ppm.

[0041] After the reactor is kept at 350℃, the inlet temperature is reduced to 260℃, and feedstock oil is introduced, initially at 30% of the designed processing load. Once stabilized, the feedstock oil rate is adjusted to 70% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0042] Example 3

[0043] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure fraction is controlled at the design pressure, and the hourly volumetric flow rate of circulating hydrogen is controlled at 600 times the total catalyst loading volume. NO gas is injected into the inlet of the hydrorefining reaction zone at a volumetric injection rate of 18% of the circulating hydrogen volumetric flow rate. The reactor inlet temperature is increased to 240°C, and when the NO2 volume fraction in the circulating hydrogen reaches 28%, the NO gas injection is stopped, and the reactor inlet temperature is reduced to 155°C.

[0044] New hydrogen is introduced into the circulating hydrogen system and introduced into the shale oil hydrogenation unit through the reaction zone to replace the gas in the reaction system. The hydrogen replacement is completed when the hydrogen gas fraction in the circulating hydrogen reaches 99%.

[0045] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 3000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 240°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 10 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 4000–5000 ppm.

[0046] After the isothermal treatment at 240℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 390℃ at a rate of 5℃ / h, and isothermal sulfidation continues for 8 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 16,000 and 18,000 ppm.

[0047] After the reactor is kept at 390℃, the inlet temperature is reduced to 260℃, and feedstock oil is introduced, initially at 40% of the designed processing load. Once stable, the feedstock oil rate is adjusted to 100% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0048] Example 4

[0049] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure fraction is controlled at the design pressure, and the hourly volumetric flow rate of circulating hydrogen is controlled at 800 times the total catalyst loading volume. NO gas is injected into the inlet of the hydrorefining zone at a volumetric injection rate of 20% of the circulating hydrogen volumetric flow rate. The reactor inlet temperature is increased to 250°C, and when the NO2 volume fraction in the circulating hydrogen reaches 30%, the NO gas injection is stopped, and the reactor inlet temperature is reduced to 155°C.

[0050] New hydrogen is introduced into the circulating hydrogen system and introduced into the shale oil hydrogenation unit through the reaction zone to replace the gas in the reaction system. The hydrogen replacement is completed when the hydrogen gas fraction in the circulating hydrogen reaches 99%.

[0051] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 4000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 250°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 8 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 5000-6000 ppm.

[0052] After the isothermal treatment at 250℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 340℃ at a rate of 6℃ / h, and sulfidation is carried out at this isothermal temperature for 10 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 23,000 and 25,000 ppm.

[0053] After the reactor is kept at 340℃, the inlet temperature is reduced to 300℃, and feedstock oil is introduced, initially at 50% of the designed processing load. Once stabilized, the feedstock oil rate is adjusted to 90% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0054] Comparative Example 1

[0055] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure separator is controlled at the design pressure, the hourly volumetric flow rate of circulating hydrogen is controlled at 800 times the total catalyst loading volume, and the reactor inlet temperature is increased to 280°C. When the volume of water generated by the high-pressure separator is 15% of the catalyst loading volume, the reactor inlet temperature is reduced to 155°C by volume.

[0056] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 4000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 250°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 8 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 5000-6000 ppm.

[0057] After the isothermal treatment at 250℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 340℃ at a rate of 6℃ / h, and sulfidation is carried out at this isothermal temperature for 10 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 23,000 and 25,000 ppm.

[0058] After the reactor is kept at 340℃, the inlet temperature is reduced to 300℃, and feedstock oil is introduced, initially at 50% of the designed processing load. Once stabilized, the feedstock oil rate is adjusted to 90% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0059] Comparative Example 2

[0060] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure separator is controlled at the design pressure, the hourly volumetric flow rate of circulating hydrogen is controlled at 400 times the total catalyst loading volume, and the reactor inlet temperature is increased to 270°C. When the volume of water generated by the high-pressure separator is 25% of the catalyst loading volume, the reactor inlet temperature is reduced to 165°C by volume.

[0061] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 2000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 250°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 6 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 3000-4000 ppm.

[0062] After the isothermal treatment at 250℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 350℃ at a rate of 5℃ / h, and the sulfidation is maintained at this temperature for 8 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 14,000 and 16,000 ppm.

[0063] After the reactor is kept at 350℃, the inlet temperature is reduced to 260℃, and feedstock oil is introduced, initially at 30% of the designed processing load. Once stabilized, the feedstock oil rate is adjusted to 70% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0064] Comparative Example 3

[0065] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure fraction is controlled at the design pressure, and the hourly volumetric flow rate of circulating hydrogen is controlled at 600 times the total catalyst loading volume. NO gas is injected into the inlet of the hydrorefining zone at a volumetric injection rate of 18% of the circulating hydrogen volumetric flow rate. The reactor inlet temperature is increased to 240°C, and when the NO2 volume fraction in the circulating hydrogen reaches 60%, the NO gas injection is stopped, and the reactor inlet temperature is reduced to 155°C.

[0066] New hydrogen is introduced into the circulating hydrogen system and introduced into the shale oil hydrogenation unit through the reaction zone to replace the gas in the reaction system. The hydrogen replacement is completed when the hydrogen gas fraction in the circulating hydrogen reaches 99%.

[0067] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 3000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 240°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 10 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 4000–5000 ppm.

[0068] After the isothermal treatment at 240℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 390℃ at a rate of 5℃ / h, and isothermal sulfidation continues for 8 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 16,000 and 18,000 ppm.

[0069] After the reactor is kept at 390℃, the inlet temperature is reduced to 260℃, and feedstock oil is introduced, initially at 40% of the designed processing load. Once stable, the feedstock oil rate is adjusted to 100% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0070] Comparative Example 4

[0071] After the catalyst loading, airtightness check, and establishment of the circulating hydrogen system are completed in the shale oil hydrotreating unit, the high-pressure fraction is controlled at the design pressure, the hourly volumetric flow rate of circulating hydrogen is controlled at 800 times the total catalyst loading volume, and the inlet temperature of the refining reactor is controlled at 155°C.

[0072] The DMDS sulfiding agent is gradually injected into the hydrorefining reaction zone using a high-pressure sulfur injection pump. The temperature is gradually increased and controlled to not exceed 230°C in the catalyst bed until the hydrogen sulfide mass concentration in the circulating hydrogen is maintained at 4000 ppm, indicating that hydrogen sulfide has penetrated the catalyst bed. Then, the reactor inlet temperature is increased to 250°C at a rate of 6°C / h, and constant-temperature sulfidation is carried out for 8 hours. During this period, the hydrogen sulfide mass concentration in the circulating hydrogen should be maintained at 5000-6000 ppm.

[0073] After the isothermal treatment at 250℃, the second sulfidation stage begins. The reactor inlet temperature is steadily increased to 340℃ at a rate of 6℃ / h, and sulfidation is carried out at this isothermal temperature for 10 hours. During this period, the hydrogen sulfide concentration in the circulating hydrogen should be maintained between 23,000 and 25,000 ppm.

[0074] After the reactor is kept at 340℃, the inlet temperature is reduced to 300℃, and feedstock oil is introduced, initially at 50% of the designed processing load. Once stabilized, the feedstock oil rate is adjusted to 90% of the designed processing load. Subsequently, the refining reaction temperature is adjusted, and the catalyst is evaluated over a long period according to the conditions in Table 3.

[0075] Table 1 Properties of Crude Oil

[0076] Crude oil name Shale oil <![CDATA[Density (20 °C), g·cm -3 (GB / T 1884)]]> 0.9038 Distillation range, °C (ASTM D1160) IBP / 10% 182 / 208 30％ / 50％ 276 / 328 70％ / 90 454 / 526 95% / EBP 546 / 578 Sulfur content, wt% 0.50 Nitrogen content, wt% 1.46

[0077] Table 2 Industrial Catalysts

[0078] Industrial agents FF-66 Physical and chemical properties Aperture / nm 2-8nm <![CDATA[Pore volume / mL·g -1 > ≥0.25 <![CDATA[Specific surface area / m 2 ·g -1 > ≥150 shape Gear ball <![CDATA[Loading bulk ratio, g / cm 3 > 0.72

[0079] Table 3 Evaluation Criteria

[0080]

[0081]

[0082] Table 4. Test Results of Examples

[0083] project Example 1 Example 2 Example 3 Example 4 Hydrogen consumption, wt% 1.2 1.3 1.4 1.3 Deactivation rate of refined catalyst, ℃ / d 0.10 0.11 0.12 0.10 Average reaction temperature for 2000 hours of refining, ℃ 385 386 388 385

[0084] Table 5. Results of the comparative experiment

[0085] project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Hydrogen consumption, wt% 1.5 1.6 1.6 1.7 Deactivation rate of refined catalyst, ℃ / d 0.16 0.17 0.18 0.19 Average reaction temperature for 2000 hours of refining, ℃ 392 393 394 395

[0086] As can be seen from the above embodiments and comparative examples, under the condition of controlling the same nitrogen content of shale oil, the start-up method of the present invention not only has low hydrogen consumption, but also slow catalyst deactivation rate.

Claims

1. A start-up method for a shale oil hydroprocessing plant, comprising: After the shale oil hydrogenation device is completed with catalyst loading, air tightness inspection, circulation hydrogen system is established, circulation hydrogen per hour volume flow control is total catalyst loading volume 100~800 times, NO gas is injected to hydrogenation refining reaction zone entrance, NO volume injection rate is 5%~20% of circulation hydrogen volume flow, reactor entrance temperature is increased to 170~250 DEG C, when circulation hydrogen NO2 volume fraction is 10%~30%, injection of NO gas is stopped, then hydrogen gas replacement, sulfuration of catalyst in hydrogenation refining reaction zone are carried out in turn, after sulfuration is completed, raw oil is introduced; The raw oil is selected from shale oil; The sulfuration process adopts dry sulfuration, and the dry sulfuration includes a first sulfuration stage and a second sulfuration stage, wherein the first sulfuration stage is to increase the inlet temperature of the hydrogenation refining reaction zone to a first constant temperature of 220-260 DEG C at a temperature increasing rate of 2-8 DEG C / h, then keep the temperature constant at the first constant temperature for 4-10 h, and the hydrogen sulfide mass concentration in the circulation hydrogen is controlled to be 2000-6000 ppm in the first sulfuration stage; the second sulfuration stage is to increase the inlet temperature of the hydrogenation refining reaction zone to a second constant temperature of 340-400 DEG C at a temperature increasing rate of 3-8 DEG C / h, then keep the temperature constant at the second constant temperature for 4-10 h, and the hydrogen sulfide mass concentration in the circulation hydrogen is controlled to be 12000-25000 ppm in the second sulfuration stage.

2. The start-up method of claim 1, wherein The hydrogen gas replacement is completed when the hydrogen volume fraction in the circulation hydrogen is adjusted to 96%-99%.

3. The start-up method according to claim 1 or 2, characterized in that, Before the hydrogen gas replacement, the inlet temperature of the hydrogenation refining reaction zone is first reduced to 150-180 DEG C, and then the hydrogen gas replacement is performed.

4. The start-up method of claim 1, wherein The dry sulfuration, before entering the first sulfuration stage, gradually injects sulfuration agent into the shale oil hydrogenation device, gradually increases the temperature, and controls the catalyst bed temperature of the hydrogenation refining reaction zone to be not more than 230 DEG C until the hydrogen sulfide penetrates the entire catalyst bed.

5. The start-up method of claim 4, wherein The condition for the hydrogen sulfide to penetrate the entire catalyst bed is that the hydrogen sulfide mass concentration in the circulation hydrogen is more than 1000 ppm.

6. The start-up method of claim 5, wherein The condition for the hydrogen sulfide to penetrate the entire catalyst bed is that the hydrogen sulfide mass concentration in the circulation hydrogen is 1000-8000 ppm.

7. The start-up method of claim 1, wherein The hydrogenation refining catalyst loaded in the hydrogenation refining reaction zone has a content of 15wt%-35wt% of Group VIB metal oxide and a content of 2wt%-10wt% of Group VIII metal oxide based on the weight of the catalyst.

8. The start-up method of claim 7, wherein The hydrogenation refining catalyst has a content of 18wt%-25wt% of Group VIB metal oxide and a content of 3wt%-8wt% of Group VIII metal oxide based on the weight of the catalyst.

9. The start-up method according to claim 1 or 4, characterized by, The sulfuration agent used in the sulfuration is at least one of dimethyl disulfide and carbon disulfide.

10. The start-up method of claim 1, wherein The raw oil has an initial boiling point of 50-100 DEG C, a final boiling point of 350-450 DEG C, a sulfur mass content of 8000 ppm or less, and a nitrogen mass content of 14000-30000 ppm.

11. The start-up method of claim 1, wherein The specific operation of introducing the raw oil is as follows: the inlet temperature of the hydrofining reaction zone is reduced to 250-300 DEG C, the raw oil is introduced, the initial introduction amount is 30-50% of the design processing load, after stabilization, the raw oil feed amount is adjusted to 60-100% of the design processing load, the reaction temperature is adjusted until the product quality is qualified.

12. The start-up method of claim 1, wherein Under normal production, the reaction conditions of the hydrofining reaction zone are as follows: the reaction pressure is 4.0-10.0 MPa, the hydrofining reaction temperature is 250-370°C, the liquid hourly space velocity of the hydrofining liquid is 0.5-4.0 h -1 .

13. The start-up method of claim 12, wherein, Under normal production, the reaction conditions of the hydrofining reaction zone are as follows: the reaction pressure is 6.0-8.0 MPa, the hydrofining reaction temperature is 300-350°C, the liquid hourly space velocity of the hydrofining liquid is 1.0-2.0 h -1 .

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