WO2007131437A1 - Hydrogenation process for coal direct liquefaction circulation solvent - Google Patents

Abstract

A hydrogenation process for brown coal direct liquefaction circulation solvent comprises two reactors, the first of which is mainly filled with protecting catalyst with lower hydrogenation activity and the second of which is primarily filled with main catalyst with higher hydrogenation activity, which forms a catalyst grading suitable for a balanced hydrogenation/dehydrogenation reaction for the solvent. Through the process, all compounds in the hydrogenated solvent can reach even degree of incomplete saturation in molecular structure, which improves transferable hydrogen content of molecules, accordingly the free hydrogen- (-H) released by circulation solvent can meet the need of hydrogen consumption of direct liquefaction of brown coal. The process can simplify the industrial process of direct liquefaction and solvent hydrogenation, reduce the device requirement, and save investment and operating cost.

Description

 Hydrogenation method of lignite direct liquefaction circulating solvent

 The invention relates to a method for hydrogenating a coal liquefaction solvent, in particular to a method for hydrogenating a lignite direct liquefaction cycle solvent. Background technique

 The direct liquefaction method of coal is generally carried out by catalytic hydrogenation of coal and mineral spirits under high temperature (400~500 ° C) rolling (10. 0~30. OMPa) to produce a liquid fuel product having a high hydrogen to carbon ratio. Used to supplement and replace the growing shortage of petroleum fuel products. In various existing direct coal liquefaction processes, some of the solvents are hydrotreated to provide a certain hydrogen supply. For example, Exxon's hydrogen-donating solvent (EDS) process and Japan's NEDOL process use fixed-bed hydrogenation technology to specifically liquefy circulating solvent hydrogenation, Germany's IG0R+ process and China's coal direct liquefaction process (Chinese patent application CN03102672. 9) The product is hydrogenated to separate the circulating solvent, the Russian low pressure liquefaction process and the Japanese lignite liquefaction process (BCL process and NBCL process) to mix the hydrogenated and non-hydrogenated solvents into a circulating solvent. Although the above process has different degrees of hydrogen supply to the solvent, the transferable hydrogen in the solvent still cannot meet the hydrogen demand of higher coal conversion rate, and a large amount of gaseous hydrogen needs to be added to the liquefaction reaction.

 Fixed bed hydrogenation technology is mainly used for secondary oil processing. Recently, it has also been used in the upgrading of coal liquefaction products. It is generally divided into two types of processes: hydrorefining and hydrocracking. The former is aimed at deep refining of products. The purpose is to lighten heavy oil. The final products of both are stable saturated hydrocarbons, so the existing fixed bed hydrogenation technology enhances the hydrogenation reaction, and the unstable unsaturated hydrocarbon content in the product is very low.

 EDS process with relatively good solvent hydrogen supply, solvent hydrogenation using traditional petroleum hydrogenation technology: trickle bed reactor, alumina supported Ni-Mo or Co-Mo catalyst, reaction temperature 370 ° C, reaction pressure llMPa. Although the hydrogenation depth of the solvent can be controlled by changing the conditions, the saturation of the hydrogenation solvent is still similar to that of the hydrogenated petroleum product, and the product having a shallower depth of hydrogenation is basically a mixture of a saturated hydrocarbon and an unsaturated hydrocarbon, which cannot provide more. The free hydrogen (H) is fully required to meet the coal liquefaction reaction. Summary of the invention

 The object of the present invention is to provide a hydrogenation process for a lignite direct liquefaction cycle solvent, which enables all compounds of the hydrogenation solvent to achieve uniform incomplete saturation in molecular structure, and can release most in coal liquefaction reaction. A large amount of free hydrogen.

The technical solution to achieve the above objectives is as follows: The invention relates to a method for hydrogenating a lignite direct liquefaction circulating solvent, which mainly comprises the following steps:

 (1) The heated raw material solvent and hydrogen enter the first reactor from the bottom of the first reactor, and the first reactor is filled with a lower hydrogenation-active protective pre-hydrogenation catalyst, and the bed temperature is 280 to 350 Ό. When the raw material solvent and the hydrogen gas are passed through the first reactor, the hydrogenation de-impuration reaction of the solvent and the pre-hydrogenation reaction of the inert unsaturated substance which is easily tempered in the solvent are carried out;

 (2) The gas-liquid mixture that completes the pre-hydrogenation reaction is discharged from the top of the first reactor, and enters the second reactor from the bottom of the second reactor, the second reactor is filled with a high hydrogenation-active main catalyst, and the bed temperature When the gas-liquid mixture is passed through the first reactor at 310 to 390 ° C, the liquid flow rate is lower than the gas flow rate, and a moderate hydrogenation reaction of the unsaturated substance and a moderate dehydrogenation reaction of the saturated substance are performed;

 (3) The gas-liquid mixture in which the hydrogenation reaction is completed is discharged from the top of the second reactor, and is passed to a hot high-pressure separator for gas-liquid separation.

 至2. 2h。 '。 The first reactor and the second reactor in a reaction pressure of 6~13MPa, a hydrogen oil volume ratio of 50~; 150, a space velocity of 0. 3~1. 2h- '.

 The liquid in the first reactor and the second reactor is a continuous phase, and the gas is a bubble dispersed phase.

The protective prehydrogenation catalyst and the main catalyst respectively adopt a porous refractory inorganic oxide or a crystalline silicate as a carrier, and a VIB and or a Group VIII metal sulfide as an active component; the protected prehydrogenated metal sulfide Included: 10~20m%, having a specific surface area of 120~200m ² /g and a pore volume of 0. 60~0. 80ml/g; the metal sulfide content of the main catalyst is 30~40ra%, having 170 ~250m ² /g of the specific surface and 0. 35~0. 45ral / g of the pore volume. '

 Preferably, the porous refractory inorganic oxide is alumina and the crystalline silicate is zeolite.

 The Group VIB metal is preferably W, Mo; the Group VIII metal is preferably Co, Ni.

 0〜 0. 8〜1. 0。 The volume ratio of 0. 4~1. 2, preferably 0. 8~1. 0.

 The present invention employs a porous refractory inorganic oxide such as alumina or a crystalline silicate such as zeolite as a carrier, and a sulfide of a VIB or Group VIII metal such as Mo, Co, Ni or the like as an active component. The hydrogenation activity is relatively low, and the metal sulphide content is 10 to 20 m%, having a specific surface area of 120 to 200 mVg and a pore volume of 0. 60 to 0. 80 ml/g; And a pore volume of 0. 35~0. 45ml/g. The specific content of the metal sulphide is 30~40m%, having a specific surface of 170~250mVg and a pore volume of 0. 35~0. 45ml/g.

The raw material solvent separated from the liquefied product contains a small amount of an impurity element which is toxic to the catalyst and a highly unsaturated substance which is easily condensed at a high temperature, so it must first pass through the first reactor packed with the protective catalyst, and is taken off at a lower temperature. In addition to toxic impurities, 'pre-hydrogenate highly unsaturated materials, and then enter the second anti-catalyst The device performs moderate hydrogenation of most unsaturated materials and moderate dehydrogenation of a small portion of saturated materials at higher temperatures. The use of the low-activity catalyst can prevent the main catalyst from being poisoned and coked by impurities, so that the activity of the catalyst can be efficiently utilized and the service life of the catalyst can be prolonged.

 The invention adopts an upflow (overflow bed) reactor, wherein the liquid in the catalyst bed is a continuous phase, the gas bubbles rise, the liquid flows upward, and the liquid storage in the bed is large, so that the petroleum fraction can be prevented from being commonly flow-down ( The trickle bed) occurs when the reactor is short-circuited by materials such as channel flow, which is beneficial to balance the residence time of the solvent in the reactor, the solvent and the catalyst are in full contact, and the temperature distribution of the catalyst bed is thickened to achieve the incomplete saturation of the solvent. The hydrogen/dehydrogenation reaction is balanced, which reduces the possibility of coexistence of unsaturated hydrocarbons and saturated hydrocarbons in the product, and avoids the incomplete saturation of the coexistence of the two.

 The invention adopts a catalyst grading technology and an appropriate chemical reaction environment to realize incomplete saturated hydrogenation of the coal liquefaction solvent under the mild process conditions, so as to increase the incompletely saturated substance in the solvent and improve the transferability in the molecule. The hydrogen content, so that the free hydrogen (H) released by the circulating solvent can meet the hydrogen consumption requirement of lignite directly liquefying under mild conditions, and it is not necessary to add gaseous hydrogen to the liquefaction reaction.

The higher the hydrocarbon saturation in the raw solvent, the more stable the molecular structure, the more difficult it is to release free hydrogen under the reaction conditions; the highly unsaturated hydrocarbons, the molecules not only can not release free hydrogen, but will absorb free hydrogen. The chemical structure tends to be stable. Therefore, in the process of coal liquefaction, the hydrogen supply of the incompletely saturated compound is greater than that of the fully saturated compound, while the highly unsaturated compound is almost impossible to supply hydrogen. ^; In order to obtain a solvent having a large supply amount of hydrogen, the principles of the present invention is a reversible reaction in accordance with each other hydrogenation and dehydrogenation of hydrocarbons using the catalyst technology and provided with an appropriate level of chemical environment, the control is not completely reversible reaction in a solvent The equilibrium is reached in the saturated hydrogenation state, so that the unsaturated substance in the solvent is moderately hydrogenated, and the saturated substance is moderately dehydrogenated.

 Due to the complex composition of lignite, the quality of lignite varies greatly from place to place, and the composition of the liquefied product and its circulating solvent varies greatly. Therefore, the pressure, temperature and space velocity of the solvent hydrogenation reaction of the present invention are widely adjusted. . On average, however, the process conditions of the present invention are much more moderate than the hydrogenation conditions of petroleum fractions.

 The reaction hydrogen oil ratio of the invention is 50~150, which is far lower than the hundreds to thousands of reaction hydrogen ratios of the petroleum fraction hydrogenation, avoiding a large excess of hydrogen, and ensuring that the solvent is not completely saturated hydrogenation/ The chemical environment in which the dehydrogenation reaction is balanced facilitates a moderate dehydrogenation reaction of a small amount of saturated hydrocarbons carried out from the liquefied product.

The invention realizes incomplete saturated hydrogenation of the coal liquefaction solvent under the mild process condition, and extracts the hydrogen supply amount of the solvent, so that the liquefaction reaction of the lignite can be completed by the hydrogen supply of the circulating solvent under the mitigation condition, and the liquefaction process does not need to provide Gas hydrogen feedstock. Therefore, the invention can simplify the process of lignite liquefaction and solvent hydrogenation, and reduce equipment requirements, Provincial investment and operating expenses.

 DRAWINGS

 The technical solution of the present invention will be described below with reference to the accompanying drawings.

 1 is a flow chart of a method for hydrogenating a lignite liquefaction cycle solvent;

1. New hydrogen L1. cooler

 2. Raw material solvent P1. Hydrogen compressor

 3. High pressure separation gas P2. Raw material oil pump

 4. Washing water R1. First reactor

 5. Condensate R2. Second reactor

 6. Circulating hydrogen VI. High pressure gas-liquid separator

 7. Hydrogenated solvent V2. Low pressure gas-liquid separator.

 F1. ^Heating furnace

 Referring to Figure 1, the raw material solvent 2 is pressurized by the feedstock oil pump P1 and combined with the mixed hydrogen (new hydrogen 1 + recycled hydrogen 6) pressurized by the compressor 'P2, and heated into the heating furnace F1. The heated solvent and hydrogen enter the first reactor R1 from the bottom. :'' The first reactor R1 is filled with a lower hydrogenation-active protective pre-hydrogenation catalyst, the bed temperature is lower, solvent and hydrogen: when the above-mentioned flow mode passes through the first reactor R1, the solvent is hydrolyzed. Pre-hydrogenation reaction of highly unsaturated substances in impurity reaction and solvent which is easily condensed at high temperature, that is, most of S, N, 0 and metal impurities in the solvent are removed by catalytic hydrogenation reaction, and highly unsaturated substances which are easily subjected to high temperature condensation reaction Pre-hydrogenation reactions such as asphaltenes and fused aromatic hydrocarbons attenuate the tendency of condensation reactions of these materials. This example employs an upflow (overflow bed) reactor in which the stream enters from the bottom of the reactor, 'exhausted from the top, the liquid in the reactor is the continuous phase, and the gas is the bubbled dispersed phase.

The gas-liquid mixture that completes the pre-hydrogenation reaction is discharged from the top of the first reactor R1, and enters the second reactor R2 from the bottom. The second reactor R2 is filled with a high hydrogenation-active main catalyst, and the bed temperature is high (specific data See Table 1). Since the gas phase is reduced by the first reactor R1 to reduce the hydrogen concentration, a chemical environment suitable for the unsaturated hydrogenation equilibrium reaction of the solvent is formed in the bed of the second reactor R2, and the gas-liquid mixture flows upward. When passing through the second reactor R2, a moderate hydrogenation reaction of the unsaturated substance and a moderate dehydrogenation reaction of the saturated substance are performed, that is, the liquid flow rate is lower than the gas flow rate, and the liquid flow is approximately in the state of the plug flow overflowing the bed, and the solvent and the catalyst are sufficient. In equilibrium with the equilibrium reaction, the catalytic hydrogenation/dehydrogenation reaction between the dissolved hydrogen and the solvent molecules in the solvent is balanced at an appropriate reaction pressure and temperature, and the solvent is not The saturated material is moderately hydrogenated, and a small portion of the saturated material from the coal liquefaction product is moderately dehydrogenated. The hydrogenation solvent achieves a uniform incomplete hydrogenation saturation in the molecular structure, forming a maximum amount in a high temperature and hydrogen deficiency environment. Free hydrogen release

The product of (-H). The hydrogenated reaction gas-liquid mixture is withdrawn from the top of the second reactor R2 and passed to a hot pressurization separator VI for gas-liquid separation.

The hydrogenation solvent 7 is discharged from the bottom of the pressure gas-liquid separator VI, and the high-pressure separation gas 3 is discharged at the top. The hydrogenation solvent 7 can be directly sent to the lignite liquefaction reaction system without lowering the temperature and pressure, and the main component of the high pressure separation gas 3 is a small amount of H ₂ 0, 3⁄4S, N3⁄4 and gas light hydrocarbons. The high pressure separation gas 3 and the wash water 4 are combined, cooled and condensed by the cooler L1, and then passed to the cold low pressure separator V2. 'Low gas is recycled hydrogen 6, which is recycled after mixing with new hydrogen 1. The condensate 5 includes wastewater + light hydrocarbons, wherein the wastewater is an aqueous solution of water-soluble gas such as 3⁄4S, N3⁄4. The condensate 5 is further separated into downstream processes for environmentally friendly treatment of light hydrocarbons and wastewater.

 循环Recycling solvent-protected pre-hydrogenation special catalyst YZC-01 (please refer to Chinese patent application CN200610035343. 7) and main hydrogenation special catalyst ZZC 02 (please refer to Chinese patent application CN200610035342. 2) according to volume ratio of 1:1 Filled in two 600 ml reactors in series, the hydrogenation test was carried out on the lignite liquefaction cycle solvent. The test conditions are shown in Table 1. The raw material oil and product properties are shown in Table 2, wherein the feedstock oil 1 was used in Example 1~ 4. Raw material oil 2 was used in the examples '5 to 6.

 The YZC-01 catalyst can be prepared as follows:

 (1) Preparation of peptizing solution and wet material

 The acidified metal salt solution was obtained by adding 10.0 g of ammonium molybdate and 7.3 g of nickel nitrate to 300 ml of distilled water to dissolve, and then adding 75 ml of 75 ml of nitric acid and stirring to obtain 335. 9 g of an acidified metal salt solution.

 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。.

5克的湿料675. 9g。 The above-mentioned peptizing solution was added to 260 _g of large-aluminum alumina and uniformly kneaded to obtain a moisture content of 45. 6m% wet material 675. 9g.

 (2) Wet strips

 8mra。 The wet strip was placed in a squeezing strip.

 (3) Extrusion drying and roasting

 0小时, Then, the above-mentioned wet extruded strip was placed in a ventilated furnace, and the temperature was raised to 125 ° C at a temperature of 150 ° C / hr, the temperature was dried at a constant temperature of 2. 0 hr, and then heated to 450 以 at the same speed, constant temperature roasting 2. 0hr, then Naturally cool down.

 (4) Preparation of impregnation solution and catalyst impregnation

40. 0g ammonium molybdate and 16.3g basic nickel carbonate were added to 60ml of an aqueous solution containing NH ₃ 15m%, H ₂ 0 ₂ 12m%, After the metal salt was completely dissolved by stirring, the pH of the solution was adjusted to 10 with ammonia water containing NH ₃ 45 m% and 12 m% to prepare 80 ml of an immersion liquid.

 80 Using the spray dipping method, all of the above 80 ml of the immersion liquid is uniformly sprayed into the dry extruded strip obtained in the step (3) to obtain a semi-dry extruded strip containing a sufficient amount of metal.

 (5) Drying and roasting of semi-dry extruded strips containing sufficient metal

 The above-mentioned semi-dry extruded strip containing sufficient metal is placed in a high-temperature furnace capable of exhausting, and is heated to 125 ° C at a temperature of 150 ° C / hr, and dried at a constant temperature of 2. 0 hr, and then heated to 450 ° C at the same speed. The temperature was calcined for 2. 0 hr, and then naturally cooled to prepare a semi-finished catalyst.

(6) Vulcanization of the semi-finished catalyst: 480 ml of CS _{2 was} added to 12,000 ml of diesel oil and uniformly mixed to prepare a sulfurized diesel oil. While maintaining a hydrogen flow rate of 5000 ml/hr under a pressure of 10 MPa, 400 g of the catalyst charged in the tubular reactor was raised to 160 Torr at 15 ° C/hr, and after a constant temperature of 2 hr, the sulphurized diesel was passed through the catalyst bed at a flow rate of 150 ml/hr. 5小时以上。 At the same temperature, the temperature of the gas phase H ₂ S concentration reached 5. 5 % or more. After the end of the 230 Γ constant temperature, it rises to 320 at 6 ° C / hr. 5小时。 C, a constant temperature of 2hr, and finally rose to 370 ° C at 8 ° C / hr, a constant temperature of 1. 5hr. Then quickly cool down to 150 Ό, vent the vulcanized diesel, keep the temperature constant and keep the hydrogen purge for 2 hr to complete the vulcanization.

 (7) Mixed oil protection of sulfided catalyst

When the above-mentioned vulcanized catalyst was thermally discharged, 80 g of a distillate oil having a wax content of 12 m% and a distillation range of 250 to 400 X 3⁄4 at a temperature of 80 ° C was uniformly sprayed on the catalyst, and then naturally cooled to room temperature. ^The 3⁄4 ZZC-02 catalyst was prepared as follows:

 (1) Preparation of peptizing solution and wet material

 The solution of 189. 3g of nitric acid was obtained by adding 18 ml of nitric acid (concentration: 75 m%) to 270 ml of distilled water and stirring.

 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。.

The wetted material having a water content of 43.8 m% is obtained by uniformly kneading the above-mentioned peptizing solution with 192 g of a large-aluminum alumina (pore volume of 0.62 ml/g), 33.3 g of ammonium molybdate, and 28.8 nickel nitrate. 623. 4 _g .

 (2) Wet strips

 8毫米。 The squeezing strip is 0. 8mm.

 (3) Extrusion drying and roasting

0小时,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,, Then naturally cool down. (4) Preparation of impregnation solution and catalyst impregnation

62. lg ammonium molybdate and 30. Og basic nickel carbonate were added to 100ml of an aqueous solution containing N 15m%, H ₂ 0 ₂ 12m%, stirred to completely dissolve the metal salt, and then contained N

The pH was 10, and 130 ml of an immersion liquid was obtained.

 The 130 ml of the above-mentioned impregnation liquid was uniformly sprayed into the dry extruded strip obtained in the step (3) by a spray dipping method to obtain a wet extruded strip containing a sufficient amount of metal.

 (5) Wet extruded strips containing sufficient metal to dry and roast

 The above-mentioned semi-dry extruded strip containing a sufficient amount of metal is placed in a high-temperature furnace capable of exhausting, and is heated to 125 V at a rate of 150 ° C / hr, and dried at a constant temperature of 2. 0 hr, and then heated to 450 Torr at the same speed, and calcined at a constant temperature of 2 0hr, then naturally cooled, to make a semi-finished catalyst.

(6) Vulcanization of the semi-finished catalyst: 480 ml of CS _{2 was} added to 12,000 ml of diesel oil and uniformly mixed to prepare a vulcanized diesel oil. While maintaining a hydrogen flow rate of 5000 ml/hr under a pressure of 10 MPa, the 400 g of the catalyst charged in the tubular reactor was raised to 1'60 ° C at 15 ° C / hr, and after 2 hr, the vulcanized diesel was passed at a flow rate of 150 ml / hr. 5小时以上。 At the temperature of the gas phase S concentration of 5. 5 % or more. After 230 Ό constant temperature, take 6. The C/hr rises to 320 °C, the temperature is 2 hr, and finally rises to 370 at 8 °C/hr. 5小时。 C, a constant temperature of 1. 5hr. Then, the temperature was rapidly lowered to 150 ° C, the vulcanized diesel was vented, the temperature was kept constant and the hydrogen was purged for 2 hr to complete the vulcanization.

 (7) Mixed oil protection of sulfided catalyst

When the vulcanized catalyst was thermally discharged, 70 g of a distillate oil having a temperature of 80 Torr and a wax content of 12 m% and a distillation range of 250 to 400 Torr ^: was sprayed onto the catalyst, and then naturally cooled to room temperature. Table 1 Test conditions for solvent hydrogenation of lignite liquefaction cycle

The data in Table 1 shows that in Examples 1 to 4, the pressure is up to 10.8 MPa of Example 3, and the lowest is 7. IMPa of Example 2. The first reactor (the temperature is up to 321 实施 of Example 4, the lowest is At 292 ° C of Example 1, the second reactor temperature was at most 360 实施 of Example 4, and the lowest was 323 ° C of Example 1 _{, and the} hydrogen to oil ratio was at most Example 4. 130 (v/v), the lowest is the 65 (v/v) of the first embodiment; the lower the space velocity is selected to be 0. 2~0. 3h - is due to the toluene insolubles of the feedstock 1 (24.9 m%) The asphaltenes (17.6 m%) in the toluene solubles are relatively high and require a longer reaction time to hydroconvert them to low molecular weight products. The raw material oils 2 of Examples 5 to 6 have a low content of the non-ideal component toluene-insoluble matter (4.3 m%) and the toluene soluble matter (1.2 m%), and are used at a relatively low space velocity (implementation Examples 5 and 6 are 0. 65h" and 1. 2h - respectively, and the temperature, pressure and hydrogen-oil ratio are compared with the marginal conditions of the present invention. The above reaction conditions belong to the medium-pressure hydrogenation category, the reaction temperature and the hydrogen-oil ratio. Both are lower.

 The unsaturated aromatic hydrocarbons and hydrogenated aromatic hydrocarbons in Table 2 were qualitatively and quantitatively analyzed by mass spectrometry, in which the hydrogenated aromatic hydrocarbons included incompletely saturated hydrocarbons of various hydrogenation numbers, and the fully saturated small amounts of cyclic hydrocarbons were merged into the group composition. In saturated hydrocarbons.

 Between the samples 1 and 4, the solvent density (20 ° C) is reduced from 1. 14 g / ml of the raw material oil to 1. 10 ~ 1. 04g / ml, the distillation range is different The degree of reduction indicates that the reaction process of the present invention effectively reduces the molecular weight of the solvent.

 The lower limit of the feedstock oil is reduced by 24. 9m% of the feedstock oil. The toluene-insoluble matter is reduced by 24. 9m% of the feedstock oil. 7m%。 The product was 14.1~10. 7m%. This indicates that the solvent hydrogenation reaction process of the present invention can convert a non-aromatic substance having a relatively large molecular weight into a substance having an aromatic ring structure.

 The sulphate and the arionite are reduced from 23.45m% of the feedstock oil to 4.66 of the product. The saturated hydrocarbon in the toluene solubles is reduced from 2.81m% of the feedstock oil to 0.44~0. 73m%.约。 67%%, the corresponding aromatic hydrocarbons increased from 73. 74m% of the feedstock oil to 92. 81~94. 61m%. It can be seen that the reaction process of the present invention not only converts the moderate dehydrogenation of the cyclic hydrazine to the aromatic substance i but also effectively decomposes the condensed ring gum and the asphaltene having a large molecular weight to the less aromatic aromatic hydrocarbons having a smaller molecular weight, and the latter is ideal. Solvent component.

The mass spectrometry data indicates that the unsaturated aromatic hydrocarbon is 53.35 ι from the feedstock oil.至约约。 This is a substantial reduction to the product of 11. 05~ 12. 01ra%, and the fully saturated hydrogenated aromatic hydrocarbon is greatly increased from 1.46m% of the feedstock oil to 69. 52~ 72. 47m%, which is exactly this A very obvious change in molecular composition greatly improves the hydrogen supply capacity of the solvent.

Table 2 Comparison of raw oil and product properties

In Example 5 and Example 6, the former has a lower pressure and space velocity than the latter, but the temperature and hydrogen oil are higher than the latter. The reaction conditions of the two groups have a certain degree of complementarity to the reaction results, so the properties of the products are not much different. Only in Example 5, because of the higher reaction temperature and longer reaction time, the cracking reaction is favored, so the solvent density (20) °C) from feedstock oil The llg/ml was reduced to 1.02 g/ml of the product, which was slightly lower than the 1.08 g/ml in Example 6. The distillation range of the product of Example 5 was lower than that of Example 6, for the reasons above.

 The pressure in Example 6 is the most entrenched, which is favorable for the hydrogenation reaction. In order to prevent the hydrogenation saturation of the product from being excessive, the lowest hydrogen to oil ratio and the maximum space velocity are used, so the hydrogenated aromatic hydrocarbon content (83.22 m%) of this example is only slightly in the case of Example 5 (80. 13ra%) 3. 09m%.

 The data in Table 2 shows that the hydrogenated aromatic hydrocarbon content of the product is still higher than that of the feedstock 1 due to the lower non-ideal component content of the feedstock oil 2, although its reaction space velocity is higher.

 Example 7 The lignite hot-melting catalytic test was carried out using the mixed products of Examples 1 to 4 as a solvent, and Example 8 was a lignite hot-melting catalytic test using a non-hydrogenated circulating solvent, and the two were compared. The test was carried out in a 2000 ύ 高压 autoclave. After the reaction material was in good shape, it was pressurized with nitrogen to the reaction pressure, the pressure was kept constant, and the temperature was raised under stirring. The test results are shown in Table 3.

 Table 3 Comparison of hot coal catalytic test of hydrogenated solvent and non-hydrogenated solvent

The data in Table 3 shows that under the same ratio of catalyst to coal and reaction conditions, the non-hydrogenated solvent has substantially no hydrogen supply, and the solvent condenses and cokes with the unsaturated substance produced by pyrolysis of coal powder under the action of high temperature and pressure. This leads to a decrease in liquid and an increase in solids. The conversion rate and oil production rate are negative, except that the water production rate and gas production rate are close to those of the hydrolyzed solvent. The hydrogenation solvent has sufficient hydrogen supply effect, and the released hydrogen combines with the unsaturated substance produced by the pyrolysis of the coal powder to form a stable liquefied product, thereby achieving the ideal hot coal catalytic conversion rate and oil production rate of the lignite.

Claims

Rights request

A method for hydrogenating a lignite direct liquefaction cycle solvent, characterized in that it mainly comprises the following steps:

(1) The heated solvent and hydrogen enter the first reactor from the bottom of the first reactor, and the first reactor is filled with a lower hydrogenation-active protective catalyst, the bed temperature is 280 to 350 Torr, solvent and hydrogen. When the above flow mode passes through the first reactor, a hydrogenation de-impuration reaction of the solvent and a pre-hydrogenation reaction of the highly unsaturated substance which is easily condensed at a high temperature in the solvent are performed;

 (2) The gas-liquid mixture that completes the pre-hydrogenation reaction is discharged from the top of the first reactor, and enters the second reactor from the bottom of the second reactor, the second reactor is filled with a high hydrogenation-active main catalyst, and the bed temperature When the gas-liquid mixture is passed through the second reactor at 310 to 390 ° C, the liquid flow rate is lower than the gas flow rate, and a moderate hydrogenation reaction of the unsaturated substance and a moderate dehydrogenation reaction of the saturated substance are performed;

 (3) The gas-liquid fluence of the hydrogenation reaction is discharged from the top of the second reactor, and is passed to a hot high pressure separator for gas-liquid separation.

2〜1. The first embodiment of the first reactor and the second reactor having a reaction pressure of 6 to 13 MPa, a hydrogen oil volume ratio of 50 to 150, a space velocity of 0. 3~1. 2h- ¹ .

 3. The method of claim 1 wherein the liquid in the first reactor and the second reactor is a continuous phase and the gas is a bubble dispersed phase.

The method according to claim 1, wherein the protective catalyst and the main catalyst each use a porous refractory inorganic oxide or a crystalline silicate as a carrier, and a VIB and or a Group VIII metal sulfide. The content of the metal sulfide of the procatalyst is 10~20m%, having a specific surface area of 120~200m7g and a content of 0. 60~0. 80ml/g of the metal sulfide content of the procatalyst. 45〜40米%, having a specific surface of 170~250m ² /g and a pore volume of 0. 35~0. 45ral / g.

 The method according to claim 4, wherein the porous refractory inorganic oxide is alumina, and the crystalline silicate is zeolite.

 6. The method according to claim 4, wherein the Group VIB metal is Mo; the Group VIII metal is Co, Ni o

 2〜1. 2。 The volume ratio of 0. 4~1.

 8〜1。 The volume ratio of the protective catalyst and the main catalyst is 0. 8~1.