Coal and oil co-hydrotreating processing technology and equipment

Abstract

An oil-coal co-hydrotreating processing includes the following steps: pulverized coal, vacuum residue and recycle oil are mixed to prepare coal slurry. After mixed with hydrogen, catalyst and additive, oil-coal slurry is preheated into a slurry bed reactor with high reacting pressure for thermal cracking and hydrogenation reaction. After reaction, all the products go into the hot high pressure separator for separation of solid from the bottom and gas from the top. The gas obtained goes into the fixed bed reactor for further hydrocracking or refining, and the distillate obtained enter the fractionating tower. The vacuum gas oil from the bottom of fractionating tower is taken as recycle oil piped to the oil-coal slurry mixing device as solvent.

Claims

1. A process for an oil-coal co-hydrotreating process, the process comprising: pulverizing the coal and drying, wherein the pulverized coal is mixed with at least one of crude oil, atmospheric residue, vacuum residue, FCC slurry oil, deasphalted oil, vacuum gas oil, and coal tar, the mixing being performed in a coal and oil mixing and pulping device to prepare an oil-coal slurry; mixing the oil-coal slurry with hydrogen, a catalyst and an additive; after the mixing, preheating the oil-coal slurry and transporting the oil-coal slurry to a slurry bed reactor with a reacting pressure for thermal cracking and hydrogenation reaction such that coke, asphaltene and heavy metals are adsorbed on the catalyst, additives and unreacted coal in the reaction process; after reaction in the slurry bed reactor, transporting all products into a hot high pressure separator for separation of solid from a bottom of thehot high pressure separator and gas from a top of the hot high pressure separator; and transporting the gas into a fixed bed reactor for further hydrocracking or refining; wherein distillate obtained from a reaction in the fixed bed reactor enters a fractionating tower, and bottom vacuum gas oil is transported to the coal and oil mixing and pulping device for recycling; wherein the catalyst is a mixture of molybdate and iron, the additive is a sulfurizing reagent, and the reaction pressure in the slurry bed reactor is in the range of 17-20 MPa.

2. The process according to claim 1, wherein a ratio of pulverized coal and residual oil is 3:97-70:30, and the ratio of the catalyst, additive and the oil-coal slurry is 0.8-1.2:2-4:100.

3. The process according to claim 1, wherein the pulverized coal has a particle size range of 50-200 m.

4. The process according to claim 1, wherein the additive comprises at least one or more of carbon disulfide, dimethyl sulfide, dimethyl disulfide, n-butyl mercaptan and sodium sulfide.

5. The process according to claim 1 wherein the catalyst is prepared by spray granulation of mixed iron powder and ammonium molybdate solution, and wherein the catalyst has a particle size of less than 10 m.

6. The process according to claim 5, wherein a mass percent concentration of the ammonium molybdate solution is 10-50%, and a molar ratio of an effective active component molybdenum to iron is 1/100 1/300.

7. The process according to claim 1, wherein a mass ratio of vacuum gas oil in the oil-coal slurry is 8-20%.

8. A coal and oil co-hydrotreating apparatus, comprising: an oil-coal slurry conveying pipe of a coal and oil mixing and pulping device; an adding device connected to the coil and oil mixing and pulping device for mixing an oil-coal slurry with a catalyst and additive; a furnace connected to the adding device and a hydrogen pipeline for preheating a an oil-coal slurry/catalyst/additive/hydrogen mixture; a slurry bed reactor connected to the furnace for performing a thermal cracking and hydrogenation reaction; a hot high pressure separator connected to the slurry bed reactor; a fixed bed reactor connected to an upper part of the hot high pressure separator; a vacuum flash tower connected to a bottom part of the hot high pressure separator; a cold high pressure separator connected to the fixed bed reactor, a top of the cold high pressure separator being connected with a gas purification device, and a bottom of the cold high pressure separator being connected with a fractionating tower; wherein only medium distributors are arranged internal to the slurry bed reactor but no support plate of the slurry bed reactor, the slurry bed reactor having an inner ceramic wall; the fractionation tower being connected to the coal and oil mixing and pulping device for recycling vacuum gas oil.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a flow diagram of example 1 of the present invention.

(2) The reference numbers in the FIGURE are listed below:

(3) 1oil-coal slurry pipeline, 2adding device, 3fresh hydrogen compressor, 4hydrogen pipeline, 5furnace, 6slurry bed reactor, 7hot high pressure separator, 8vacuum flash tower, 9fixed bed reactor, 10cold high pressure separator, 11gas purification device, 13fractionator.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Example 1

(4) The results of this example are from a pilot test of a single oil which continuous test period of 15 days, and the device and process are shown in FIG. 1. The oil-coal slurry is made of vacuum residue (properties in Table 1), coal powder (properties in Table 2) and recycle vacuum gas oil, and is piped by the oil-coal slurry pipeline 1. Hydrogen is transported through pipeline 4 and pressurized by fresh hydrogen compressor 3. The oil-coal slurry, catalyst and additive are mixed in adding device 2 and the mixture is transported to heating furnace 5 with hydrogen injection, and the mixture goes into the slurry bed reactor 6 after increasing temperature and pressure. The additive of the example is carbon disulfide. The molar ratio of effective components of molybdenum and iron is 1:1501:170, and the catalyst is made by spray granulation of mixed iron powder and ammonium molybdate solution to ensure the smooth surface for catalyst. The catalysts are small solid particles with sizes below 50 m and insoluble in oil and water. The proportion of each substance follows the following basic process parameters, and the system is heterogeneous reaction. Inside the slurry bed reactor 6, there is only a medium distributor, but no support plate of bed, and the inner wall is made of ceramic.

(5) The oil-coal slurry in the slurry bed reactor 6 under high partial pressure of hydrogen undergoes catalytic thermal cracking reaction in the presence of catalyst. The asphaltene, coke, and heavy metals in the reaction process are adsorbed on the carbon disulfide, which can ensure the long period operation of slurry bed reactor. Newly developed exclusive catalyst can make the reaction faster and overcome the shortcomings of the insufficient reaction time in the reactor caused by backmixing of residue, and can make the reaction pressure lower (see the following basic parameters) and inhibit the coke formation. Compared to other forms of reactor, pressure drop of the slurry bed reactor is lower. The inner wall of the reactor uses the ceramic tube to reduce the friction of the medium and the vessel wall which can greatly reduce the wall effect of fluid and avoid the fluid to attach to the wall and scaling problems caused by the high viscosity of the medium. Moreover, the reaction pressure of the reactor is moderate, and the catalyst is easy to prepare and the cost is low for using domestic raw material to synthesize the catalyst.

(6) The reaction products then enter the hot high pressure separator 7. The relatively clean gas products is isolated from the top of hot high pressure separator 7, and the catalyst, additive and unreacted coal carrying asphaltene, carbon residue, sediment, metal and other solid enter the vacuum distillation tower 8 from the bottom of hot high pressure separator 7. Further hydrogenation or cracking will be taken for gas products in fixed bed reactor 9. The asphaltene, carbon residue, sediment, metal etc. are mostly removed in slurry bed reaction and separated in the bottom of hot high pressure separator 7, so they will not produce serious influence for catalyst bed of the fixed bed and it can guarantee long period operation of fixed bed reactor 9. The gas products are further processed into the cold high pressure separator 10, and the separated products are fractionated into naphtha, diesel oil, vacuum gas oil and other products in the fractionating tower 13. The vacuum gas oil in the bottom of the tower is recycled to the oil-coal slurry tank according to the amount of online oil circulation to reduce the viscosity of the oil-coal slurry. The gas enters gas purification device 11 for desulfurization, and the dry gas after purified is discharged. The property of the product is shown in table 3.

(7) The basic process data of the present example are as follows:

(8) TABLE-US-00001 TABLE 1 vacuum residue properties Project Value Density(20 C. )g/cm.sup.3 1.044 Kinematic viscosity(mm.sup.2/s) 2658.7 Freezing point( C.) 45 Carbon residue wt % 24.89 Ash content wt % 0.13 Acid value mg KOH/g 1.81 Components analysis wt % C 86.79 H 10.34 C/H (molar ratio) 1.39 S 2.39 N 0.83 SARA analysis wt % Saturates 23.24 Aromatics 39.5 Resin 24.61 Asphaltene 12.59 Heavy metals wt g/g Ni 108.2 V 402 Na 33.1 Mg 14.2 Cu 0.25

(9) TABLE-US-00002 TABLE 2 Pulverized coal properties Project Unit Value Industrial analysis % air-dried moisture Mad 19.56 Air as received basis Aar 11.22 Air dried basis Ad 17.03 Volatile matter on dry basis Vd 36.07 Volatile matter on dry ash-free basis Vdaf 43.47 Fixed carbon on dried basis FCd 46.93 Calorific value MJ/Kg Gross calorific value as dried basis Qgr, d 21.8 Gross calorific value as dry ash-free Qgr, daf 26.3 basis Net calorific value as air dried basis Qnet, ad 17.9 Net calorific value as received basis Qnet, ar 14.4 Element analysis % Carbon content as received basis Car 39.71 Carbon content as dried basis Cd 60.26 Carbon content as dry ash-free basis Cdaf 72.62 Hydrogen content as received basis Har 2.59 Hydrogen content as dried basis Hd 3.93 Hydrogen content as dry ash-free basis Hdaf 4.74 Nitrogen content as received basis Nar 0.62 Nitrogen content as dried basis Nd 0.94 Nitrogen content as dry ash-free basis Ndaf 1.13 Total sulfur content as received basis St, ar 1 Sulfur content as dried basis Sd 1.52 Sulfur content as dry ash-free basis Sdaf Oxygen content as received basis Oar 10.79 Oxygen content as dried basis Od 16.37 Oxygen content as dry ash-free basis Odaf Hardgrove grind ability index HGI 50

(10) TABLE-US-00003 TABLE 3 Product properties Light gas 12.8% Light oil 78.9% Residue slurry 12.3% Total(100 + Hydrogen consumption) 104.0%

(11) In the present example, the basic technological parameters of slurry bed in pilot test are presented: Temperature: 440-460 C.; Experimental pressure: 17-18 Mpa; Hydrogen to feed ratio: 1000:11400:1; Space velocity: 0.5 h.sup.1; Mass quality ratio of oil/coal: 30:70 The total mss quality of the recycle vacuum gas oil is 8%; The catalyst/feed coal slurry (WT): 1/100; Vulcanizing/feed coal slurry (WT): 2.5/100; Chemical hydrogen consumption (hydrogen/feed) in slurry bed: 4/100 (WT).

Example 2

(12) The operation flow of the example is roughly the same as example 1, and the difference is that the mass ratio of the oil to the coal in the feed is changed to 50:50.

(13) The residue and the coal of the present example 2 is in accordance with example 1, and the catalytic active components of iron-molybdenum are within the ratio of 1:1701:200 with the size less than 50 m by spray granulation.

(14) The basic technological parameters of the slurry bed are described in the present example: Temperature: 450-470 C.; Experimental pressure: 18-20 Mpa; Hydrogen to oil ratio: 900:11200:1; Space velocity: 0.6 h.sup.1; Mass quality ratio of oil/coal: 50:50; The ratio of recycle vacuum gas oil to total feed: 20%; Catalyst/feed residue: 1.0/100 (WT); Vulcanizing agent/feed residue: 3.5/100 (WT); Chemical hydrogen consumption (hydrogen/feed) in slurry bed: 2.8-4.1/100 (WT) (WT).

(15) The properties of the product of this example is shown in table 4.

(16) TABLE-US-00004 TABLE 4 Product properties Light gas 14.7% Light oil 75.2% Residue slurry 14.5% Total(100 + Hydrogen consumption) 104.4%

(17) It can be seen through the above examples that high light oil yield can be obtained in low pressure environment by this technical improvement. Especially, the increase of solid content, can significantly save costs, improve efficiency, and can make great contributions for the nation to face tighter supplies of crude oil and energy saving.

(18) The above are only preferred embodiments of the present invention, but the scope of the invention is not limited to them. Any change or replacement which can be easily thought of by a person skilled in this art such as the proportion of each component in the reasonable adjustment range or something else, should be covered within the scope of the present invention. Therefore, the scope of the present invention shall be in accordance with the scope of protection of the claims.