CN109913264B - Coal tar boiling bed-fixed bed combined process starting method - Google Patents
Coal tar boiling bed-fixed bed combined process starting method Download PDFInfo
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Abstract
The invention discloses a start-up method of a coal tar boiling bed-fixed bed combined process, which comprises the following steps: firstly, a fixed bed hydrogenation device is vulcanized, then a material obtained in the reaction process of the fixed bed hydrogenation device is used as vulcanized oil in the start-up process of a boiling bed hydrogenation device, and the vulcanization processes of the two hydrogenation devices are organically combined into a whole and mutually supported, so that the problem of pipeline blockage in the start-up process of the existing vulcanization process can be solved.
Description
Technical Field
The invention relates to a start-up method of a coal tar hydrogenation process, in particular to a start-up method of a coal tar combined hydrogenation process.
Background
In the hydrogenation technology of heavy coal tar distillate or whole coal tar distillate, at the time of starting up the device, the catalyst is usually sulfurized by using petroleum distillate such as diesel oil or kerosene, and then the coal tar raw material is replaced. Because the heavy fraction or the whole fraction of the coal tar contains high content of polycyclic aromatic hydrocarbon, colloid and asphaltene, the substance has great difference with the polarity of diesel oil used in start-up and poor intersolubility, the phenomenon of polar substance precipitation in the coal tar is easy to occur in the process of switching raw materials in start-up, so that a raw material pump or a pipeline is blocked, and the device cannot be normally started up. In addition, the high-temperature coal tar has extremely poor property, the activity of the catalyst is very high after the catalyst is vulcanized, the catalyst can be quickly deactivated when the catalyst is directly contacted with the coal tar, the carbon deposition of a catalyst bed layer is serious, and the service life of the catalyst is influenced.
Patent CN 101148596a introduces a start-up method of coal tar hydrotreating process, in the start-up initial stage, after vulcanization is finished, one or more of coker diesel oil, coker gas oil, catalytic diesel oil, catalytic recycle oil, deasphalted oil, coal liquefied diesel oil fraction, coal liquefied wax oil fraction, wax oil after coal tar hydrotreating and diesel oil fraction are selected as diluent oil, then polar substances such as alcohols, phenols, esters and other polar substances are selected, finally the polar substances are added into the diluent oil according to a certain proportion, the prepared diluent oil containing the polar substances is directly added into a reactor, and finally the coal tar raw material is switched. In the method, the former stage vulcanization still adopts the traditional residual oil hydrogenation device vulcanization method, distillate oil and polar substances are additionally selected after the vulcanization is finished, and diluent oil is prepared according to a certain proportion, so that the device is relatively complex in operation.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a new mode of a start-up method of a coal tar boiling bed-fixed bed combined process, the method can ensure the vulcanization of the catalyst, and the start-up method is simple and easy to implement.
The invention provides a start-up method of a coal tar boiling bed-fixed bed combined process, which comprises the following steps:
(1) firstly, vulcanizing a fixed bed hydrogenation device;
(2) after the fixed bed hydrogenation device is vulcanized, introducing coal tar atmospheric and vacuum distillate oil, carrying out hydrogenation reaction on the coal tar atmospheric and vacuum distillate oil and hydrogen in the fixed bed hydrogenation device, and obtaining fixed bed hydrogenation generated oil after the reaction;
(3) performing first-stage vulcanization on the fluidized bed hydrogenation device, taking a hydrogenated diesel fraction obtained by fractionating oil generated by hydrogenation of the fixed bed in the step (2) as start-up vulcanized oil for the first-stage vulcanization of the fluidized bed hydrogenation device, mixing the start-up vulcanized oil with a vulcanizing agent, and feeding the mixture into the fluidized bed hydrogenation device for vulcanization, wherein the fluidized bed hydrogenation device is a circulation flow;
(4) after the first-stage vulcanization of the fluidized bed hydrogenation device is finished, setting the flow of the fluidized bed hydrogenation device from a circulation flow to a one-time pass flow, gradually introducing the full fraction of the fixed bed hydrogenation generated oil obtained by the fixed bed hydrogenation device in the step (2) in proportion as transition oil to carry out second-stage vulcanization, and then, allowing the reaction generated oil obtained by the fluidized bed hydrogenation device to enter an intermediate storage tank for storage;
(5) and after the second-stage vulcanization of the fluidized bed hydrogenation device is finished, proportionally switching coal tar raw materials into the fluidized bed hydrogenation device until all the coal tar raw materials are switched, proportionally stopping introducing coal tar atmospheric and vacuum distillate oil into the fixed bed hydrogenation device, proportionally switching the fixed bed hydrogenation device into a fractionating system which proportionally introduces the fluidized bed hydrogenation device to fractionate the obtained liquid-phase materials, and gradually putting the whole device into normal operation.
According to the method, the coal tar boiling bed-fixed bed combined process comprises the steps that the coal tar raw material firstly enters a boiling bed hydrogenation device for hydrogenation reaction, and the generated oil obtained through hydrogenation reaction enters a fixed bed hydrogenation device for hydrogenation treatment. The fluidized bed hydrogenation device is provided with more than one fluidized bed hydrogenation reactor, preferably 1-2 fluidized bed hydrogenation reactors, and the fixed bed hydrogenation device is provided with more than one fixed bed hydrogenation reactor, preferably 2-4 fixed bed hydrogenation reactors.
In the method, the coal tar fixed bed hydrogenation device vulcanization in the step (1) comprises the following contents:
(1.1) starting a recycle hydrogen compressor to establish gas circulation after the fixed bed hydrogenation device is airtight and qualified, and raising the inlet temperature of a bed layer of a fixed bed hydrogenation reactor to 150-200 ℃;
(1.2) introducing start-up vulcanized oil and a vulcanizing agent into a fixed bed hydrogenation reactor, and after hydrogen sulfide penetrates through the fixed bed hydrogenation reactor, increasing the inlet temperature of the fixed bed hydrogenation reactor to ensure that the temperature of each point of a reactor bed layer reaches 230-260 ℃, and carrying out constant-temperature vulcanization for 5-10 hours;
(1.3) continuously heating the fixed bed hydrogenation reactor to 270-300 ℃, and carrying out constant-temperature vulcanization for 2-4 h; in the temperature-rising vulcanization process, H in the circulating gas at the outlet of the reactor2The concentration of S is maintained to be 0.5 to 1.0v percent;
(1.4) continuously heating the fixed bed hydrogenation reactor to 370-400 ℃, adjusting the sulfur injection amount, and enabling H in the circulating gas2The concentration of S is 1.0-2.0 v%, the constant temperature vulcanization is carried out for more than 8h, and the start-up vulcanization is finished.
In the method, the start-up vulcanized oil in the step (1.2) can be straight-run kerosene obtained by fractionating crude oil, and can also be coal tar hydrogenated kerosene fraction, and the nitrogen content is required to be less than 100 mu g/g; the sulfur content is not more than 5000 mug/g; the dry point is 280-310 ℃.
The vulcanizing agents described in the above process are those commonly used in the art. The vulcanizing agent may be elemental sulfur, inorganic and/or organic sulfides. The following conditions are preferably satisfied: in the presence of hydrogen and a catalyst, the vulcanizing agent can be decomposed into H2S at a lower reaction temperature so as to improve the vulcanizing effect; the sulfur content of the vulcanizing agent is high; the cost is low and the method is easy to obtain; low toxicity and high safety. According to the above requirements, the sulfurizing agent can be chosen from the group consisting of mercaptans, disulfides, polysulfides and thiophenecarboxylic acid compounds: typically, one or more of carbon disulfide (CS 2), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), and SZ-54 are more commonly used.
In the method, the temperature rise speed of the fixed bed hydrogenation reactor is 6-10 ℃/h, and when the temperature rise of the reactor is obvious, the temperature rise speed needs to be controlled to be less than 6 ℃/h.
In the method, the coal tar atmospheric and vacuum distillation fraction in the step (2) is the light components left after tail oil is cut off from the whole coal tar fraction, the distillation range of the atmospheric and vacuum distillation fraction is 160-500 ℃, preferably 200-480 ℃, and preferably the coal tar atmospheric and vacuum distillation fraction is obtained by distilling the raw material coal tar of an ebullated bed hydrogenation device. The coal tar raw material is any one of medium-low temperature coal tar, high-temperature coal tar or wood tar produced in the coal chemical industry and other industries at present.
In the method, the coal tar atmospheric and vacuum distillation fraction in the step (2) is subjected to hydrogenation reaction in a fixed bed hydrogenation device, wherein the hydrogenation reaction conditions are as follows: the reaction temperature is 270-370 ℃, the reaction pressure is 10-18 Mpa, and the volume airspeed is 0.2-2.0 h-1The volume ratio of hydrogen to oil is 500-1000: 1; the preferable reaction temperature is 280-320 ℃, the reaction pressure is 12-15 Mpa, and the volume space velocity is 0.5-1.0 h-1And the volume ratio of hydrogen to oil is 600-800: 1. The phase difference value of the total aromatic hydrocarbon content before and after hydrogenation of the coal tar atmospheric and vacuum distillate is controlled to be between 10% and 20%.
In the method, the coal tar atmospheric and vacuum distillation fraction in the step (2) is subjected to hydrogenation reaction in a fixed bed hydrogenation device, and the fixed bed hydrogenation produced oil obtained after the reaction enters a fixed bed hydrogenation device fractionation system and can be fractionated into various materials as required. The distillation range of the hydrogenated diesel oil fraction is 180-350 ℃. It can also be fractionated to obtain hydrogenated gasoline (final boiling point less than 180 deg.C) and hydrogenated heavy oil (initial boiling point greater than 350 deg.C).
In the method, when the first-stage vulcanization of the fluidized bed device is carried out in the step (3), the hydrogenated diesel oil fraction obtained after the oil generated by the fixed bed hydrogenation in the step (2) is fractionated is used as the start-up vulcanized oil, the start-up vulcanized oil is recycled in the fluidized bed hydrogenation device, and the circulation flow of the fluidized bed hydrogenation device is that the start-up vulcanized oil is recycled in the fluidized bed hydrogenation device.
In the process of the present invention, the vulcanizing agent described in step (3) is a vulcanizing agent commonly used in the art. The vulcanizing agent may be elemental sulfur, inorganic and/or organic sulfides. The following conditions are preferably satisfied: in the presence of hydrogen and catalyst, the sulfurizing agent can be decomposed into H at lower reaction temperature2S, to improve the vulcanization effect; the sulfur content of the vulcanizing agent is high; the cost is low and the method is easy to obtain; low toxicity and high safety. According to the above requirements, the sulfurizing agent can be chosen from the group consisting of mercaptans, disulfides, polysulfides and thiophenecarboxylic acid compounds: typically, one or more of carbon disulfide (CS 2), dimethyl sulfide (DMS), dimethyl disulfide (DMDS), and SZ-54 are more commonly used.
In the method of the invention, the first-stage vulcanization of the fluidized bed in the step (3) comprises the following steps:
(3.1) firstly raising the inlet temperature of a fluidized bed hydrogenation reactor to 150-200 ℃, fractionating the fixed bed hydrogenation produced oil to obtain hydrogenated diesel oil fraction serving as start-up vulcanized oil for first-stage vulcanization of the fluidized bed hydrogenation device, injecting a vulcanizing agent into the start-up vulcanized oil, then continuously raising the temperature of the reactor to 230-260 ℃, and carrying out constant-temperature vulcanization for 6-10 hours;
(3.2) raising the temperature of the fluidized bed hydrogenation reactor to 270-300 ℃, and operating at constant temperature until a gas phase outlet H2The concentration of S reaches more than 1.0 v%.
In the method of the invention, the second-stage vulcanization in the boiling bed in the step (4) comprises the following steps: setting the flow of the fluidized bed hydrogenation device as a one-time pass flow from a circulation flow, gradually increasing and introducing the whole fraction of the fixed bed hydrogenation generated oil obtained by the fixed bed hydrogenation device in the step (2) as transition oil to carry out second-stage vulcanization, simultaneously reducing the introduction of the hydrogenation diesel fraction and a vulcanizing agent in proportion, raising the temperature of the reactor of the fluidized bed hydrogenation device to 350-390 ℃, carrying out constant-temperature vulcanization for 5-8 hours, and at the moment, storing the reaction generated oil obtained by the fluidized bed hydrogenation device in an intermediate storage tank.
In the method, the whole fraction of the fixed bed hydrogenation generated oil obtained by introducing the fixed bed hydrogenation device in the step (2) is gradually increased in proportion to be used as transition oil for carrying out second-stage vulcanization, and meanwhile, the introduction of the hydrogenated diesel oil fraction and the vulcanizing agent is reduced in proportion, so that the proportion of the transition oil in the feed of the boiling bed hydrogenation device can be gradually increased by 2-10 times to be changed into the transition oil, the proportion of each increase can be the same or different, and the operation process is well known by the technicians in the field. Specifically, the transition oil may be replaced by 20% transition oil (20 wt% transition oil in the feed, 80wt% hydrogenated diesel oil, the same applies below), 40% transition oil, 60% transition oil, 80% transition oil and 100% transition oil, respectively, with an interval of 2 hours or more. Adjusting the reaction temperature to meet the requirements of products, and finally replacing with 100 percent of transition oil.
In the method, in the step (5), after the second-stage vulcanization of the fluidized bed hydrogenation device is finished, the inlet temperature of the fluidized bed hydrogenation device is reduced to 230-320 ℃, then coal tar raw materials are proportionally switched into the fluidized bed hydrogenation device until all coal tar raw materials are switched into the coal tar raw materials, the coal tar atmospheric and vacuum distillate oil is proportionally stopped from being introduced into the fixed bed hydrogenation device, the fixed bed hydrogenation device is switched into a fractionation system which is proportionally introduced into the fluidized bed hydrogenation device for fractionation, and the whole device is gradually put into normal operation.
In the method, after the fluidized bed device is vulcanized in the step (5), the coal tar raw materials are gradually introduced according to a proportion, the temperature is raised simultaneously in the switching process, the principle of 'raising the quantity first and then raising the temperature' is followed in the operation process, namely, after the coal tar raw materials are introduced according to a certain proportion, the outlet temperature of a heating furnace is raised by 10-20 ℃ at the speed of 5-10 ℃/h, the temperature rise condition in a reactor is observed, after the device is stabilized for 24 hours, the coal tar feeding amount is raised according to the proportion (the equal proportion transition oil feeding amount is reduced simultaneously), the temperature is raised, the previous step is repeated, the temperature raising process is slow, and the temperature rise change in the reactor is noticed; finally, switching to a coal tar raw material full-load feeding device, stopping the injection of the transition oil, and performing the reaction in a stable operation.
In the method, the coal tar raw materials are switched into the fluidized bed hydrogenation device according to the proportion until all the coal tar raw materials are switched into the coal tar raw materials, the proportion of the coal tar raw materials in the feeding of the fluidized bed hydrogenation reactor can be gradually increased for 2-10 times to change into the coal tar, the increasing proportion can be the same or different, and the operation process is well known by the technical personnel in the field. Specifically, 10% of coal tar (10% by mass of coal tar in the feed, 90% by mass of start-up transition oil, the same applies below), 20% of coal tar, 30% of coal tar, 40% of coal tar, 50% of coal tar, 60% of coal tar, 70% of coal tar, 80% of coal tar, 90% of coal tar and 100% of coal tar may be respectively replaced by coal tar step by step, and the interval between the replacement of each coal tar is generally 2 hours or more. Adjusting the reaction temperature to meet the requirements of products, and finally replacing 100% of coal tar.
In the method, the reaction product oil obtained by the fluidized bed hydrogenation device in the step (4) enters an intermediate storage tank for storage, and after the whole device is started, the reaction product oil can be used as a raw material of the fluidized bed hydrogenation device and introduced into a fluidized bed hydrogenation reactor for reaction.
The operating conditions in the start-up process of the fluidized bed hydrogenation device in the method are as follows: the vulcanization pressure is 13-18 MPa, the volume ratio of hydrogen to oil is 300: 1-1500: 1, and the volume airspeed is 0.2-1.0 h-1The vulcanization temperature range is 150-380 ℃; the preferable operation conditions are that the reaction pressure is 15-17 MPa, the volume ratio of hydrogen to oil is 500: 1-1000: 1, and the volume airspeed is 0.3-0.7 h-1And the vulcanization temperature is 175-375 ℃.
The operating conditions in the process of starting the fixed bed hydrogenation device in the method are as follows: the vulcanization pressure is 13-18 MPa, the volume ratio of hydrogen to oil is 300: 1-1500: 1, and the volume airspeed is 0.2-1.0 h-1The vulcanizing temperature range is 150-380 DEG C(ii) a The preferable operation conditions are that the reaction pressure is 15-17 MPa, the volume ratio of hydrogen to oil is 500: 1-1000: 1, and the volume airspeed is 0.3-0.7 h-1And the vulcanization temperature is 175-375 ℃.
In the method, the hydrogenation catalyst filled in the boiling bed hydrogenation device is a conventional boiling bed hydrogenation catalyst in the field, generally, VIB group and/or VIII group metals are used as active components, alumina or silicon-containing alumina is used as a carrier, the VIB group metals are generally Mo and/or W, and the VIII group metals are generally Co and/or Ni. Other adjuvants may also be present. The ebullated bed hydrogenation catalyst can be selected from commercial products and can also be prepared by adopting the existing method in the field.
In the method, the hydrogenation catalyst filled in the fixed bed hydrogenation device is a fixed bed hydrogenation catalyst commonly used in the field, generally, VIB group and/or VIII group metals are used as active components, alumina or silicon-containing alumina is used as a carrier, the VIB group metals are generally Mo and/or W, the VIII group metals are generally Co and/or Ni, and other auxiliary agents can be further contained. The variety of commercial catalysts to be selected is various, such as hydrogenation catalysts developed by the research and development of the petrochemical research institute (FRIPP), such as FF-26, FC-24 and the like; conventional hydrogenation catalysts may also be prepared as desired according to common general knowledge in the art.
Compared with the prior art, the method has the following advantages:
the invention provides a brand new mode start-up method aiming at a combined fluidized bed-fixed bed process taking coal tar as a raw material. And the coal tar hydrogenated diesel distillate oil and the full fraction are used as start-up vulcanized oil and transition oil, so that the problem of pipeline blockage in the start-up process of the existing vulcanization process can be solved; moreover, the startup method can solve the technical problems that in the prior art, a large amount of heat is released from a reactor in the startup process, and the heat release of the whole device is uncontrollable.
Detailed Description
The invention is further described below by means of specific embodiments without limiting the scope of protection of the invention.
The coal tar boiling bed-fixed bed combined process starting method comprises the following steps: firstly, carrying out vulcanization on a catalyst in a fixed bed hydrogenation reactor, feeding straight-run kerosene and a vulcanizing agent into the fixed bed hydrogenation reactor for vulcanization, returning the vulcanized oil from a bottom return line of a hot low fraction after the vulcanized oil is subjected to hot high fraction and hot low fraction to the fixed bed hydrogenation reactor to realize closed cycle vulcanization, introducing normal pressure reduction fraction obtained by coal tar distillation into the fixed bed hydrogenation reactor for hydrogenation reaction after the vulcanization of the fixed bed hydrogenation reactor is finished, feeding hydrogenated naphtha, hydrogenated diesel oil and hydrogenated heavy oil after hydrogenated oil is subjected to hot high fraction and hot low fraction of the fixed bed hydrogenation reactor and normal pressure tower fractionation, feeding the hydrogenated diesel oil into a boiling bed hydrogenation reactor after the hydrogenated diesel oil is returned to an inlet of the boiling bed hydrogenation reactor to be mixed with the vulcanizing agent to start first-stage vulcanization of the boiling bed catalyst, and feeding the vulcanized oil back to the inlet of the boiling bed hydrogenation reactor to realize closed cycle vulcanization after the hot high fraction and, after the hydrogenation diesel oil is vulcanized, changing a circulation flow into a one-time flow in a fluidized bed hydrogenation reactor, introducing a hot low-phase synthetic oil full fraction after the fixed bed hydrogenation reactor to an inlet of the fluidized bed hydrogenation reactor to serve as vulcanized oil (transition oil, and at the moment, the vulcanizing agent is stopped being injected) in a second stage of the fluidized bed hydrogenation reactor, after the vulcanization of the vulcanized oil in the second stage is finished, stopping the coal tar oil atmospheric pressure reduction fraction in the fixed bed hydrogenation reactor, and connecting the fluidized bed hydrogenation reactor and the fixed bed hydrogenation reactor in series. After the sulfurization is finished, the feeding amount of the coal tar raw material at the inlet of the fluidized bed hydrogenation reactor is gradually increased in proportion, meanwhile, the proportion of transition oil is reduced, the inlet temperature of the fluidized bed hydrogenation reactor is slowly increased, and finally, the full coal tar raw material feeding device is switched to realize the stable operation of the device.
In the start-up method, the boiling bed hydrogenation device is filled with the FEC catalyst, and the specific properties of the catalyst are shown in the table 3; FMJ-2 and FMJ-3 catalysts are filled in the fixed bed hydrogenation device, the specific properties of the catalysts are shown in Table 4, and the specific vulcanization operation processes of the two sets of devices are as follows:
(1) after the fixed bed hydrogenation device is qualified in air tightness, starting a recycle hydrogen compressor to establish gas circulation, and raising the temperature of a bed inlet of a fixed bed hydrogenation reactor to 150-200 ℃;
(2) introducing start-up vulcanized oil straight-run kerosene and a vulcanizing agent DMDS into a fixed bed hydrogenation reactor, and after hydrogen sulfide penetrates through the fixed bed hydrogenation reactor, increasing the inlet temperature of the fixed bed hydrogenation reactor to ensure that the temperature of each point of a reactor bed layer reaches 230-260 ℃, and carrying out constant-temperature vulcanization for 5-10 hours;
(3) continuously heating the fixed bed hydrogenation reactor to 270-300 ℃, and carrying out constant temperature vulcanization for 2-4 h; in the temperature-rising vulcanization process, H in the circulating gas at the outlet of the reactor2The concentration of S is maintained to be 0.5 to 1.0v percent;
(4) when the bed temperature of the fixed bed hydrogenation reactor reaches 370-400 ℃, the sulfur injection amount is adjusted to ensure that H in the circulating gas2The concentration of S is 1.0-2.0 v%, the constant temperature vulcanization is carried out for more than 8 hours, and the start vulcanization is finished.
After the start-up vulcanization of the fixed bed hydrogenation reactor is finished, the fluidized bed hydrogenation reactor is vulcanized, and the vulcanization step comprises the following steps:
(5) firstly, raising the temperature of an inlet of a fluidized bed hydrogenation reactor to 150-200 ℃, fractionating oil generated by fixed bed hydrogenation to obtain hydrogenated diesel oil fraction serving as start-up vulcanized oil for first-stage vulcanization of a fluidized bed hydrogenation device, injecting a vulcanizing agent DMDS into the start-up vulcanized oil, then continuously raising the temperature of the reactor to 230-260 ℃, and carrying out constant-temperature vulcanization for 6-10 hours;
(6) the temperature of the fluidized bed hydrogenation reactor is increased to 270-300 ℃, and the fluidized bed hydrogenation reactor is operated at constant temperature until a gas phase outlet H2The concentration of S reaches more than 1.0 v%.
(7) And (3) setting the flow of the fluidized bed hydrogenation device as a one-time pass flow from a circulation flow, gradually increasing and introducing the whole fraction of the fixed bed hydrogenation generated oil obtained by the fixed bed hydrogenation device in the step (2) as transition oil to carry out second-stage vulcanization, simultaneously reducing the introduction of hydrogenated diesel oil fraction and a vulcanizing agent in proportion, raising the temperature of a reactor of the fluidized bed hydrogenation device to 350-390 ℃, carrying out constant-temperature vulcanization for 5-8 hours, and after the vulcanization is finished, allowing the reaction generated oil obtained by the fluidized bed hydrogenation device to enter an intermediate storage tank to be stored.
(8) After the second-stage vulcanization of the fluidized bed hydrogenation device is finished, reducing the inlet temperature of the fluidized bed hydrogenation device to 230-320 ℃, gradually introducing a coal tar raw material in proportion, simultaneously heating up in the switching process, and in the operation process, following the principle of 'first increasing and then increasing temperature', namely introducing a certain proportion of the coal tar raw material, then increasing the outlet temperature of the heating furnace by 10-20 ℃ at the speed of 5-10 ℃/h, observing the temperature increase condition in the reactor, after the device is stabilized for 24 hours, further increasing the coal tar feeding device amount in proportion (simultaneously reducing the equal proportion transition oil feeding device amount), increasing the temperature, repeating the previous step, wherein the temperature increase process is slow, and the temperature increase change in the reactor is noticed; finally, switching to a coal tar raw material full-load feeding device, stopping the injection of the transition oil, and performing the reaction in a stable operation.
TABLE 1 Low temperature coal tar Properties
TABLE 2 high temperature coal tar Properties
TABLE 3 FEC ebullated bed catalyst Properties
TABLE 4 Main physicochemical Properties of fixed bed hydrogenation catalysts
Example 1
In the embodiment 1, the medium and low temperature coal tar in the table 1 is used as a raw material, and the properties of the medium and low temperature coal tar are shown in the table 1 by adopting the start-up method provided by the invention. The ebullated-bed hydrogenation device is provided with an ebullated-bed hydrogenation reactor, an FEC catalyst is filled in the ebullated-bed hydrogenation reactor, and the specific properties of the catalyst are shown in Table 3. The fixed bed hydrogenation device is provided with two fixed bed hydrogenation reactors which are connected in series and respectively filled with FMJ-2 and FMJ-3 catalysts, and the specific properties of the catalysts are shown in Table 4. The initial vulcanized oil of the fixed bed hydrogenation reactor adopts straight-run kerosene which is directly obtained by distilling petroleum-based crude oil, the vulcanizing agent is DMDS, and the maximum initial sulfur injection rate of the catalyst vulcanization can be estimated according to an empirical value of 50kg of DMDS/10000NM3/h of circulating hydrogen. In the first-stage vulcanized oil in the boiling bed hydrogenation reactor, the hydrogenated diesel fraction is obtained by performing fixed bed hydrogenation separation on the medium-low temperature coal tar, the vulcanizing agent is DMDS, the injection flow rate of DMDS is adjusted to ensure that the sulfur content in the vulcanized oil is maintained at 1.5%, the second-stage vulcanized oil is the full fraction obtained by performing fixed bed hydrogenation on the medium-low temperature coal tar, the specific start-up conditions are shown in Table 5, and the heating speed in the vulcanization period is 8 ℃/h.
Example 2
The method is basically the same as example 1, except that the raw material is high-temperature coal tar, the specific properties are shown in Table 2, the specific start-up operating conditions are different, and the specific start-up operating conditions are shown in Table 5.
Comparative example 1
The method is basically the same as that of the example 1, except that the first-stage vulcanized oil of the boiling bed hydrogenation reactor in the comparative example 1 is the straight-run diesel oil, and the sulfur injection amount is the same as that in the example 1; the second-stage vulcanized oil adopts straight-run VGO, and the straight-run diesel oil and the straight-run VGO are directly obtained by petroleum-based crude oil distillation. See table 5 for specific start-up conditions.
Comparative example 2
The method is basically the same as the example 2, except that the first-stage vulcanized oil of the fluidized bed hydrogenation reactor in the comparative example 2 adopts straight-run diesel oil, and the second-stage vulcanized oil adopts straight-run VGO, wherein the straight-run diesel oil and the straight-run VGO are directly obtained by distillation of petroleum-based crude oil. See table 5 for specific start-up conditions.
TABLE 5 coal tar fluidized bed pretreatment-fixed bed hydrotreatment device startup procedure
It can be found from the examples and comparative examples that the normal operation of the device can be ensured by using the operation method described herein to perform operation, the pipeline cannot be blocked, and the pipeline is easily blocked when the petroleum-based distillate oil is used for operation, so that the operation method described herein is superior to the conventional operation method.
Claims (25)
1. A start-up method of a coal tar boiling bed-fixed bed combined process comprises the following contents:
(1) firstly, vulcanizing a fixed bed hydrogenation device;
(2) after the fixed bed hydrogenation device is vulcanized, introducing coal tar atmospheric and vacuum distillate oil, carrying out hydrogenation reaction on the coal tar atmospheric and vacuum distillate oil and hydrogen in the fixed bed hydrogenation device, and obtaining fixed bed hydrogenation generated oil after the reaction;
(3) performing first-stage vulcanization on the fluidized bed hydrogenation device, taking a hydrogenated diesel fraction obtained by fractionating oil generated by hydrogenation of the fixed bed in the step (2) as start-up vulcanized oil for the first-stage vulcanization of the fluidized bed hydrogenation device, mixing the start-up vulcanized oil with a vulcanizing agent, and feeding the mixture into the fluidized bed hydrogenation device for vulcanization, wherein the fluidized bed hydrogenation device is a circulation flow;
(4) after the first-stage vulcanization of the fluidized bed hydrogenation device is finished, setting the flow of the fluidized bed hydrogenation device from a circulation flow to a one-time pass flow, gradually introducing the full fraction of the fixed bed hydrogenation generated oil obtained by the fixed bed hydrogenation device in the step (2) in proportion as transition oil to carry out second-stage vulcanization, and then, allowing the reaction generated oil obtained by the fluidized bed hydrogenation device to enter an intermediate storage tank for storage;
(5) and after the second-stage vulcanization of the fluidized bed hydrogenation device is finished, proportionally switching coal tar raw materials into the fluidized bed hydrogenation device until all the coal tar raw materials are switched, proportionally stopping introducing coal tar atmospheric and vacuum distillate oil into the fixed bed hydrogenation device, proportionally switching the fixed bed hydrogenation device into a fractionating system which proportionally introduces the fluidized bed hydrogenation device to fractionate the obtained liquid-phase materials, and gradually putting the whole device into normal operation.
2. The start-up method according to claim 1, wherein the coal tar boiling bed-fixed bed combined process is that the coal tar raw material firstly enters a boiling bed hydrogenation device for hydrogenation reaction, and the produced oil obtained from the hydrogenation reaction enters a fixed bed hydrogenation device for hydrogenation treatment.
3. The start-up method according to claim 1, wherein the ebullated-bed hydrogenation apparatus is provided with more than one ebullated-bed hydrogenation reactor, and the fixed-bed hydrogenation apparatus is provided with more than one fixed-bed hydrogenation reactor.
4. The start-up method according to claim 1 or 3, wherein the ebullated-bed hydrogenation apparatus is provided with 1-2 ebullated-bed hydrogenation reactors, and the fixed-bed hydrogenation apparatus is provided with 2-4 fixed-bed hydrogenation reactors.
5. The start-up method according to claim 1, wherein the coal tar fixed bed hydrogenation unit vulcanization in the step (1) comprises the following steps:
(1.1) starting a recycle hydrogen compressor to establish gas circulation after the fixed bed hydrogenation device is airtight and qualified, and raising the inlet temperature of a bed layer of a fixed bed hydrogenation reactor to 150-200 ℃;
(1.2) introducing start-up vulcanized oil and a vulcanizing agent into a fixed bed hydrogenation reactor, and after hydrogen sulfide penetrates through the fixed bed hydrogenation reactor, increasing the inlet temperature of the fixed bed hydrogenation reactor to ensure that the temperature of each point of a reactor bed layer reaches 230-260 ℃, and carrying out constant-temperature vulcanization for 5-10 hours;
(1.3) continuously heating the fixed bed hydrogenation reactor to 270-300 ℃, and carrying out constant-temperature vulcanization for 2-4 h; in the temperature-rising vulcanization process, H in the circulating gas at the outlet of the reactor2The concentration of S is maintained to be 0.5 to 1.0v percent;
(1.4) continuously heating the fixed bed hydrogenation reactor to 370-400 ℃, adjusting the sulfur injection amount, and enabling H in the circulating gas2The concentration of S is 1.0-2.0 v%, the constant temperature vulcanization is carried out for more than 8h, and the start-up vulcanization is finished.
6. The start-up method according to claim 5, wherein the start-up vulcanized oil in the step (1.2) is straight kerosene obtained by fractionating crude oil or kerosene fraction obtained by hydrogenating coal tar.
7. The process of claim 5 wherein the nitrogen content of said process sulfur oil in step (1.2) is less than 100 μ g/g; the sulfur content is not more than 5000 mug/g; the dry point is 280-310 ℃.
8. The start-up method according to claim 1, wherein the vulcanizing agent is elemental sulfur, inorganic and/or organic sulfide.
9. A start-up method according to claim 1 or 8, wherein the sulfurizing agent is a thiol, disulfide, polysulfide or thiophenecarboxylic acid compound.
10. A start-up process according to claim 9, wherein said sulfiding agent is carbon disulfide (CS)2) One or more of dimethyl sulfide (DMS), dimethyl disulfide (DMDS) and SZ-54.
11. The start-up method according to claim 5, wherein the temperature rise rate of the fixed bed hydrogenation reactor is 6-10 ℃/h.
12. The start-up method according to claim 1, wherein the coal tar atmospheric and vacuum distillation fraction in the step (2) is a light component left after tail oil is removed from coal tar whole fraction, and the distillation range of the atmospheric and vacuum distillation fraction is 160-500 ℃.
13. The start-up method according to claim 1, wherein the coal tar atmospheric and vacuum distillation fraction in the step (2) is a light component left after tail oil is removed from coal tar whole fraction, and the distillation range of the atmospheric and vacuum distillation fraction is 200-480 ℃.
14. The start-up method according to claim 1, wherein the coal tar atmospheric and vacuum distillation fraction in the step (2) is a coal tar atmospheric and vacuum distillation fraction obtained by distilling raw material coal tar of an ebullated bed hydrogenation unit.
15. The start-up method according to claim 1, wherein the coal tar atmospheric and vacuum distillation fraction in the step (2) is subjected to hydrogenation reaction in a fixed bed hydrogenation device, and the hydrogenation reaction conditions are as follows: the reaction temperature is 270-370 ℃, the reaction pressure is 10-18 Mpa, and the volume airspeed is 0.2-2.0 h-1The volume ratio of hydrogen to oil is 500-1000: 1.
16. The start-up method according to claim 1 or 15, wherein the coal tar atmospheric and vacuum distillation fraction in the step (2) is subjected to hydrogenation reaction in a fixed bed hydrogenation device, and the hydrogenation reaction conditions are as follows: the reaction temperature is 280-320 ℃, the reaction pressure is 12-15 Mpa, and the volume airspeed is 0.5-1.0 h-1And the volume ratio of hydrogen to oil is 600-800: 1.
17. The start-up method according to claim 1, wherein the phase difference value of the total aromatic hydrocarbon content of the coal tar atmospheric and vacuum distillation cut before and after hydrogenation in the step (2) is between 10% and 20%.
18. The start-up method according to claim 1, wherein when the first-stage vulcanization of the ebullated-bed apparatus is performed in step (3), the hydrogenated diesel oil fraction obtained by fractionating the fixed-bed hydrogenation-produced oil in step (2) is used as the start-up vulcanized oil, the start-up vulcanized oil is recycled in the ebullated-bed hydrogenation apparatus, and the recycle of the ebullated-bed hydrogenation apparatus is that the start-up vulcanized oil is recycled in the ebullated-bed hydrogenation apparatus.
19. A start-up process according to claim 1, wherein said first stage ebullated-bed sulfiding in step (3) comprises the following:
(3.1) firstly raising the inlet temperature of a fluidized bed hydrogenation reactor to 150-200 ℃, fractionating the fixed bed hydrogenation produced oil to obtain hydrogenated diesel oil fraction serving as start-up vulcanized oil for first-stage vulcanization of the fluidized bed hydrogenation device, injecting a vulcanizing agent into the start-up vulcanized oil, then continuously raising the temperature of the reactor to 230-260 ℃, and carrying out constant-temperature vulcanization for 6-10 hours;
(3.2) raising the temperature of the fluidized bed hydrogenation reactor to 270-300 ℃, and operating at constant temperature until a gas phase outlet H2The concentration of S reaches more than 1.0 v%.
20. A start-up process according to claim 1, wherein the second stage ebullated-bed sulfiding in step (4) comprises the following: setting the flow of the fluidized bed hydrogenation device as a one-time pass flow from a circulation flow, gradually increasing and introducing the whole fraction of the fixed bed hydrogenation generated oil obtained by the fixed bed hydrogenation device in the step (2) as transition oil to carry out second-stage vulcanization, simultaneously reducing the introduction of the hydrogenation diesel fraction and a vulcanizing agent in proportion, raising the temperature of the reactor of the fluidized bed hydrogenation device to 350-390 ℃, carrying out constant-temperature vulcanization for 5-8 hours, and at the moment, storing the reaction generated oil obtained by the fluidized bed hydrogenation device in an intermediate storage tank.
21. The start-up method according to claim 1, wherein in the step (5), after the second-stage vulcanization of the fluidized bed hydrogenation device is finished, the inlet temperature of the fluidized bed hydrogenation device is reduced to 230-320 ℃, then coal tar raw materials are proportionally switched into the fluidized bed hydrogenation device until all coal tar raw materials are switched into the coal tar raw materials, the coal tar atmospheric and vacuum distillate oil is proportionally stopped from being introduced into the fixed bed hydrogenation device, the fixed bed hydrogenation device is switched into a fractionating system which is proportionally introduced into the fluidized bed hydrogenation device to fractionate the obtained liquid-phase materials, and the whole device is gradually put into normal operation.
22. According to claim 1The start-up method of (1), wherein the operating conditions in the start-up process of the fluidized bed hydrogenation unit are as follows: the vulcanization pressure is 13-18 MPa, the volume ratio of hydrogen to oil is 300: 1-1500: 1, and the volume airspeed is 0.2-1.0 h-1And the vulcanization temperature range is 150-380 ℃.
23. The start-up process of claim 1 or 22, wherein the operating conditions during start-up of the ebullated-bed hydrogenation unit are: the vulcanization pressure is 15-17 MPa, the volume ratio of hydrogen to oil is 500: 1-1000: 1, and the volume airspeed is 0.3-0.7 h-1And the vulcanization temperature is 175-375 ℃.
24. The start-up method according to claim 1, wherein the operating conditions during the start-up of the fixed bed hydrogenation apparatus are: the vulcanization pressure is 13-18 MPa, the volume ratio of hydrogen to oil is 300: 1-1500: 1, and the volume airspeed is 0.2-1.0 h-1And the vulcanization temperature range is 150-380 ℃.
25. The start-up method according to claim 1 or 24, wherein the operating conditions during the start-up of the fixed bed hydrogenation apparatus are: the vulcanization pressure is 15-17 MPa, the volume ratio of hydrogen to oil is 500: 1-1000: 1, and the volume airspeed is 0.3-0.7 h-1And the vulcanization temperature is 175-375 ℃.
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| CN102641749A (en) * | 2011-02-17 | 2012-08-22 | 中国石油化工股份有限公司 | Prevulcanization method of hydrotreatment catalyst |
| CN103059937A (en) * | 2011-10-21 | 2013-04-24 | 中国石油化工股份有限公司 | Startup method of hydrocracking device |
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| CN101148596A (en) * | 2006-09-20 | 2008-03-26 | 中国石油化工股份有限公司 | Work starting method for coal tar hydrotreatment technique |
| CN102641749A (en) * | 2011-02-17 | 2012-08-22 | 中国石油化工股份有限公司 | Prevulcanization method of hydrotreatment catalyst |
| CN103059937A (en) * | 2011-10-21 | 2013-04-24 | 中国石油化工股份有限公司 | Startup method of hydrocracking device |
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