JPS58129092A - Coal liquefaction - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to the production of C5-482°C from relatively low reactivity coal.
The present invention relates to a coal liquefaction process for producing a yield of 0.5-900° F. liquid product. More particularly, the present invention incorporates a relatively low reactivity feed slurry with recycle slurry from a liquefaction process using a relatively high reactivity coal to obtain a total liquid yield from the relatively low reactivity coal. It is concerned with coal liquefaction process to improve efficiency.

BACKGROUND OF THE INVENTION Coal liquefaction processes have been developed to convert coal into liquid fuel products. For example, U.S. Pat.
, 884,794 discloses a coal liquefaction process for producing reduced or low ash hydrocarbon solid fuels and hydrocarbon distillate liquid fuels from ash-containing raw coal; The process involves passing the feed coal slurry and recycled solvent through a preheater to
The presence of solvent and recycled coal minerals continuously dissolves and increases the yield of liquid product).

Generally, these processes require minimally reactive coal to maintain normal operation. Conventional processing of generally less reactive coals results in poor liquid production, high viscosity slurries, and increased coking in the process vessel due to, for example, high yields of insoluble organics. Heron coal, found in many areas of the United States, is a low reactivity type and it is therefore desirable to use this type of low reactivity coal as a liquefaction feedstock to increase the flexibility of plant operations.

DISCLOSURE OF THE INVENTION The coal liquefaction process of the present invention provides a total liquid yield (C-482°C, C5-900°C) from relatively low reactivity coal.
F) The process was discovered to improve coal of relatively low reactivity, hydrogen, recycled usually solid dissolved carbon, recycled process solvent, recycled mineral residues,
and the presence of a recirculated slurry obtained by processing relatively highly reactive coal and subjecting it to a coal liquefaction process. More particularly, the process combines hydrogen and a first feed slurry based on relatively highly reactive feed coal, recycled usually solid dissolved coal, recycled process solvent and recycled mineral residue into a first coal liquefaction zone. to produce a hydrocarbon gas and a first reaction slurry.

The slurry has a distillate liquid and a first heavy portion, usually consisting of solid molten carbon and mineral residues.

and a second feed slurry based on hydrogen and a relatively low reactivity feed carbon, recycled normally solid dissolved carbon, recycled process solvent, recycled mineral residue and a portion of said first heavy fraction. , and a second coal liquefaction zone to produce hydrocarbon gas and a second reaction slurry. The slurry has a distillate liquid and a second heavy portion, usually consisting of solid molten carbon and mineral residues. At least a portion of the second heavy fraction is passed through a gasification zone where oxygen and water or steam are injected. The gasification sphere contains an oxidizing volume within which hydrocarbonaceous materials are converted to synthesis gas. This gas is converted into a hydrogen-rich stream in a shift reaction.

A first portion of the hydrogen-rich stream is passed as process hydrogen to a first liquefaction sphere, and a second portion of the hydrogen-rich stream is passed as process hydrogen to a second coal liquefaction sphere.

Surprisingly, the yields are higher than those achieved by mixing highly reactive coals in the feed slurry used to treat less reactive coals and reacting them together at the same coal liquefaction amount.
42 It has been found that the total liquid yield can be increased. Furthermore, even if recirculated slurry is recovered from coal liquefaction processes that treat more reactive coals, the continuous addition of highly reactive feed coals to constantly replenish the recirculated slurry can be detrimental to this type of process. will not be given.

The reaction slurry from a relatively low reactivity coal conversion process has a relatively low catalytic activity of mineral components and therefore requires relatively little additional catalyst assistance when recycled to the reactor. However, according to the process of the present invention, almost all of the gasification feed is provided by reaction slurry from low activity threads, thereby minimizing the amount of such slurry recycled to the reactor. The vaporizer converts the hydrocarbonaceous material into synthesis gas, which in turn is a highly reactive compound.
It is converted to hydrogen to supply the required hydrogen for both the one-coal conversion system and the low reactivity coal conversion system.

As used herein, "low reactivity coal" and "
The expression "highly reactive coal" is relative and not absolute. Therefore, "highly reactive coal"
For example, about 438° to 460°C (820° to 86°C)
0°F), slurry residence time of 30 to about 100 minutes, 105 to 175 kg/ctd (1500 to 25
00 psig) and a hydrogen feed rate of 2.0 to 6.0 wt.% of the total slurry feed, at least 20% or preferably more than that given by "low reactivity" coal. is 30% larger amount and 0
5-+82°C (C5-900°1?) means a feed coal capable of providing liquid.

A "low reactivity coal" suitable for use in the present invention includes, for example, an organic sulfur content of 1.6% by weight or less (based on MF coal) and a raw ore sulfur content of not more than 1.2% by weight. content. Similarly, a suitable "highly reactive coal" for example is 1.6
Organic sulfur content of not less than 1.2% by weight (based on MF coal) and raw ore sulfur content of not less than 1.2% by weight. but,
Both types of coal are used in the process of the present invention as a "high" reactivity coal and a "low" reactivity coal that differs in their ability to produce C5-900°F liquid depending on the amount required. It can be used as coal.

The expression "mineral residue" is also meant to consist of inorganic mineral matter and insoluble organic matter as determined by ash analysis. Inorganic mineral material here means "ash" even if the process stream does not pass through a combustion process. "Organic vacuum bottoms" means (1) insoluble organic matter in mineral residues, and (2) soluble 482°C+ (900°F+) vacuum residues referred to as 1 usually solid dissolved charcoal. When recovered as a product of a process, solid dissolved carbon is typically referred to as "solvent refined carbon.""Distillateliquid" has a general boiling point range of 38° to 482°C (1
00° to 900° F.), but such liquids do not necessarily have to cover the entire range. "
A "process solvent" can serve as a solvent for a process and is typically from about 177q to about 482°C (from about 1150° to about 90 (l″F), preferably from about 232° to about 482°C).
(about 450° to about 900°F).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in the drawings, dry, highly reactive coal is passed via line IO to a slurry mixing tank 12 where recycled normally solid molten coal enters in line 14. , mixed with a recycled slurry containing recycled mineral residue and recycled process solvent.

The resulting feed slurry is passed through line 16 to reciprocating pump 18
is mixed with recycled hydrogen entering from line 20, passed through a tubular preheater 23 in furnace 22, and discharged via line 24 to reactor 26.

The temperature of the reactants at the outlet of the preheater is e.g.
0-427°C (approximately 700°-800°F). At this temperature, the coal has partially dissolved in the recycled process solvent and has just begun the exothermic hydrogenation and hydrocracking reactions. While the temperature increases gradually along the length of the preheater tube, the reactor is generally at a uniform temperature throughout, and the heat generated by the hydrocracking reaction in reactor 26 is kept within the desired range. Rise.

The temperature of the reactor is from about 800° to about 870°F, preferably from about 820° to about 860°F. The coal concentration in the total feed slurry is, for example, about 20-50% by weight, preferably 25-40% by weight. The slurry residence time of the feed slurry within the long turbidity %m%&b reaction zone is, for example, about 1
5 to about 120 minutes, preferably about 30 to about 100 minutes. The hydrogen partial pressure, defined as the product of the molar fraction of hydrogen and the total pressure in the total gas stream fed to the reactor, is approximately 70
~ Approx. 280 kg/crl (Approx. 1000 ~ Approx. 4000
psig), about 105 to about 175 kg/c
rl (about 1500 to about 2500 psig) is preferred. The hydrogen feed rate is about 1.0 to 10.0, preferably 2.0 to 6.0, expressed as weight percent of the total slurry feed.

The reactor effluent is routed via line 29 to vapor-liquid separation system 3.
Pass it to 0. Vapor-liquid separation system 30 consists of a set of heat exchangers and a vapor-liquid separator that converts the reactor effluent into a non-condensable gas stream 32, condensed light liquid distillate in line 34, and condensed light liquid distillate in line 5.
Separate into 6 reaction slurries. The condensed light liquid distillate from the separator is passed via line 34 to atmospheric fractionator 36. The non-condensable gas in line 32, consisting of unreacted hydrogen, methane and other light hydrocarbons, as well as H2S and CO8, is passed through acid gas removal unit 38 to remove H8 and CO8.

The recovered hydrogen sulfide is converted to elemental sulfur and removed from the process via line 40. A portion of the purified gas is transferred to line 4.
1 and 42 to cryogenic unit 44 for further processing, with bulk methane and ethane being removed as line gas via line 46 and propane and butane being removed as LPG via line 48. Purified hydrogen in line 50 mixes with residual gas from the acid gas treatment step in line 52;
Lines 53 and 20 contain process recycled hydrogen.

The reaction slurry from vapor-liquid separation unit 30 passes through line 56 and contains distillate liquid, usually solid dissolved carbon, and mineral residues having relatively high catalytic activity. Stream 56 splits into two streams 58 and 60, which are of the same composition as line 56.

In fractionator 36, the reaction slurry product from line 61 is atmospherically distilled to remove a column naphtha stream via line 62, a middle distillate stream via line 64, and a bottoms stream via line 66. do. The bottoms stream in line 66 is passed via line 67 to vacuum distillation column 68. The feed temperature to the fractionation system is typically maintained at a sufficiently high level that no additional preheating is required apart from the start-up operation.

A blend of fuel oil from the atmospheric column in line 64 and heavy distillate recovered from the vacuum column via line 70 creates a fuel oil product that is recovered via line 72. The flow in line 72 is 198° to 482°C (380° to 900°
°F) distillate liquid, a portion of which is recycled via lines 73 and 14 to feed slurry mixing tank 20 to adjust the solids concentration in the feed slurry. Recirculation flow 73
provides flexibility to the process by varying the proportion of process solvent to total recycled slurry that is recycled, so that this proportion is not determined by the proportion prevailing in line 58 for the process. It can also improve the pumping ability of the slurry. The portion of stream 72 that is not recycled via line 73 represents the distillate liquid product from the process.

The bottoms from vacuum distillation column (VTR) 68, which typically contains solid dissolved carbon and mineral residues but little distillate liquid or hydrocarbon gases, is passed through lines 74, 75 and 76 to a slurry mixing tank. Passed to 78.

Also, slurry in line 66 containing heavy distillates, typically solid dissolved carbon and mineral residues, may be passed to slurry mixing tank 78 via lines 77, 75 and 76. Furthermore, the reaction slurry was transferred to line 60°63.
and 76 to a slurry mixing tank 78 . These can be used in combination, i.e. to provide a highly reactive mineral residue to the slurry mixing tank 78.
1 or l of lines 74, 77 and/or 63)
Combine 1. The amount of mineral residue and normally solid molten coal passed through line 76 to slurry mixing tank 78 is about 10 to about 50%, preferably about 15 to about 50%, of the mineral residue and normally solid molten coal present in line 56. 40 minutes
and the remainder is recycled to slurry mixing tank 12 via lines 58 and 14.

The slurry rich in catalytic mineral residue is mixed in line 76 with relatively less reactive feed coal introduced via line 80 and recycle slurry in line 82 to form feed slurry 84, which is It is passed through pump 86, mixed with recirculated slurry in line 88, and passed through a preheater 90 in a furnace 92, as described above in connection with highly reactive coal systems. Transfer the preheated slurry to line 9.
4 to reactor 96. The temperature of the reactor is approximately 427
° to approximately 466 °C (approximately 800 ° to approximately 870 °F); approximately 438 ° to approximately 160 °C (approximately 820 ° to approximately 860 °F)
°F) is preferred. The coal concentration in the total feed slurry is, for example, about 20-50% by weight, with 25-40% by weight being heavier. The slurry residence time of the feed slurry within the reaction zone is, for example, about 15 to about 120 minutes, and about 30 to about 1
00 minutes is preferred. Hydrogen partial pressure is defined as the molar portion of hydrogen in the total gas stream fed to the reactor and the product of the total pressure, ranging from about 70 to about 280 kg/crl (about 100
0 to about +000 PSig) and about 105 to about 175 kg/cl (about 1500 to about 2500 psi
g) is preferred. The hydrogen feed rate is approximately 1.0-1010 as a weight percent of the total slurry feed, and 2.0-6.
0 is preferred, and the reactor effluent is passed via line 68 to vapor-liquid separation system 1.
00, the reactor effluent is separated into a non-condensable gas stream 102, a condensed light liquid distillate stream 104, and a reaction slurry in line 106 in the manner described in vapor-liquid separation system 30. Similarly, non-condensable gas is passed via line 108 to gas removal unit 110 and elemental sulfur is removed via line 112 in the same manner as with acid gas removal thread 38.

The purified gas is passed through lines 114 and 116 to cryogenic unit 118 for further processing, with methane and ethane being removed as line gas in line 120 and propane and butane being removed as LPG via line 122. Purified hydrogen in line 124 mixes with residual gas from the acid gas treatment step in line 126 and is recycled to the process via lines 128, 130, and 88.

The reaction slurry from the vapor-liquid separation unit (100) passes through line 106 and contains distillate liquid, usually solid molten carbon, and catalytic mineral residue.

After the yarn reaches steady state, the catalytic mineral residue in line 106 consists of mineral residues from both high and low reactivity coals, but the beneficial effects of the high reactivity mineral residues are larger than would be expected based on the actual proportion to the less reactive mineral residues. Stream 106 can be split into two streams 132 and 134, which are of the same composition as line 106. line 10
About 25% to about 75% by weight, preferably about 35% to about 60% by weight of the reaction slurry of No. 6 is passed through line 132 to fractionator 1.
Pass it to 38.

Fractionator 138 performs atmospheric distillation of the reaction slurry product from line 132 , resulting in an overhead naphtha stream via line 100 , a middle distillate stream via line 142 , and a middle distillate stream via line 142 .
Remove the bottoms stream via 4. The bottoms stream in line 144 is passed to vacuum distillation column 146. A blend of fuel oil from the atmospheric column in line 142 and heavy distillate recovered from the vacuum column via line 146 constitutes the fuel oil product and is recovered via line 150. The flow in line 150 is similar to the flow previously described in connection with line 72, and flows through lines 152 and 82 to slurry mixing tank 7.
8 can be recycled.

The bottoms from vacuum distillation column (VTR) 146 , which typically contains solid dissolved carbon and mineral residues but little distillate liquid or hydrocarbon gases, is passed through line 154 to partially oxidized gasified amount 156 . Passed.

Nitrogen-free oxygen for gasification quantity 156 is prepared in oxygen plant 158 and passed to the gasification quantity via line 160. Steam is supplied to the gasification volume via line 162. line 1 to discharge the total mineral content of the feed coal supplied by line 8o and the mineral content of the recirculated slurry in line 76 from the bottom of the gasification volume 15fi.
64 as an inert slag.

Synthesis scum is produced in a gasified volume 156 and passed via line 168 to a shift reactor 170 for conversion by a shift reaction that converts steam and CO to H2 and Co2, and then passed to an acid gas removal zone 172. Remove H2S and CO2.

Purified hydrogen obtained from heavy gas removal zone 172 is compressed to process pressure and fed via line 174 and stream 176
and 178, each with a low reactivity coal reactor 9
6 and high reactivity coal reactor 26 with prepared hydrogen. A quantity of hydrocarbonaceous residue is obtained from both the high reactivity system and the low reactivity system in line 154.
It is an important feature of the present invention that the prepared hydrogen is fed to both yarns by being formulated as a gasification feed of .

Partial oxidation gasification volume 156 was operated as described in Schmidt, US Pat. No. 4,159,236.

The invention will now be explained with reference to examples. % is expressed in weight % unless otherwise specified.

EXAMPLES The highly reactive coal treated in the examples of the present invention is Irish coal, and the less reactive coal is Edna coal, the components of each of which are shown in Table 1.

Table 1 Carbon 69.81 71.74 Hydrogen 5.10
5.13 Nitrogen 1.54 1.00 Chlorine 0.15 0.11 Diff 12.08
5.83 Sulfur @ 0.68 4.48 Ash 10.64 11.71 Sulfur shaped raw ore 0.13 2.07 Sulfate 0.01 0
．． 01 Organic matter 0.54 2.40
Total Quantity 0.68 4.48 The high reactivity coal and the low reactivity coal are each treated in separate reactors, with the high reactivity coal reactor forming a portion of the feed slurry and the low reactivity coal forming part of the feed slurry. The total liquid yield passed through the reactor (C5 - 482 °C, C, -900
A test was conducted to demonstrate the effect on the temperature (°F) compared to physically mixing a high reactivity coal with a low reactivity coal and reacting this mixture in the same reactor.

The feed slurry was prepared by mixing high reactivity pulverized coal and/or low reactivity pulverized coal with recycle slurry and recycle solvent to form the feed slurry. The feed slurry contained about 20 to about 40 weight percent feed coal.

Each feed slurry is passed through a tubular preheater with hydrogen to a continuous reactor where the mixture is heated to 400-470°C.
105-210 kg/Cr&
The reaction was carried out at a total pressure of (1500-8000 psig). A nominal slurry residence time of 0.3 to 1.5 hours was used in each case. The reaction effluent was separated and analyzed to determine the total liquid yield. This kind of coal liquefaction threat
- A correlative numerical model was developed and used for comparison. The results are shown in Table 2 below.

Coal reactivity Low High “” 50:50 5
0+50 low; high* 451°c, 157.5 kg/c++! (
2250 psig).

In Table 2, data from a single run at a residence time of 1 hour and a coal concentration of 930 wt. Using the reactor combination where the reactor has low reactivity coal, the liquid yield is 43.0 wt@% (Test 3) at 900"F. Low reactivity. When processing coal of C5-482°
The yield of C(9oo°F) is only 28.8% by weight (Test 1). When processing highly reactive coals, C15-
The yield at 482°C (900″F) is 45.4% by weight (Test 2). When mixing high and low reactivity coals 50:50, C5-482°C ( 9
00°F) yield is less than 40% by weight (Test 4 is 3
9.4, test 5 was 38.7). Therefore, the results in Table 2 surprisingly demonstrate that by simply using separate reactors for high and low reactivity coals, respectively, in the combined process of the present invention, high reactivity It has been shown that higher liquid yields are achieved than when coal and low reactivity coal are combined to feed into the same reactor.

[Brief explanation of the drawing]

Figures 1a and ib are both schematic flow diagrams of the process of the present invention. 12... Slurry mixing tank 18... Reciprocating pump 22... Furnace 23... Preheater 26... Reactor 30... Vapor-liquid separation system 36... Vapor pressure fractionator 38. ...Acidic gas removal unit 44...Low humidity unit fi
8...Vacuum distillation column 78...Slurry mixing tank 86...Pump 90...
・P heater 92... Furnace 1 liter ($... Reactor 1.00... Steam-liquid separation thread
110...Acidic gas removal unit
+18...low temperature unit l;38...
Fractionator 1・[6...Vacuum distillation column 15t1...
・Partial oxidation gasification amount 158...Oxygen plant 170...Inside shift reactor 172...Acid gas removal zone FIG, fb

Claims (1)

Claims: 1. In liquefying coal to produce improved C5-900'F liquid yields, hydrogen and relatively low reactivity feed coal, recycled. A feed slurry based on a heavy fraction, typically solid molten carbon and mineral residues, typically obtained from a coal liquefaction process using solid molten carbon, recycled process solvent, recycled mineral residues, and highly reactive feed coals. is passed through a coal liquefaction volume to produce a reaction slurry consisting of hydrocarbon gases, and distillate liquids and a heavy portion, usually consisting of solid dissolved carbon and mineral residues. In liquefying coal to produce a liquid yield (C5-482°C05-900°F), hydrogen and highly reactive feed coal, recycled normally solid dissolving coal, recycled process solvent and A first feed slurry based on recycled mineral residue is passed through a first coal liquefaction volume comprising hydrogen gas, and distillate liquid, and a first heavy portion typically consisting of solid dissolved coal and mineral residue. producing a first reaction slurry, hydrogen, and a second slurry based on a low reactivity feed carbon, recycled normally solid dissolved carbon, recycled process solvent, recycled mineral residue, and said first heavy portion; passing the feed slurry through a second coal liquefaction quantity to produce a second reaction slurry consisting of hydrocarbon gases and distillate liquids and a second heavy distillate portion, typically consisting of solid dissolved coal and mineral residue; A coal liquefaction method comprising the steps of recycling a portion of the second reaction slurry to the second coal liquefaction zone. & said step further comprises passing at least a portion of said second heavy portion as a vaporizer feed slurry through a gasification sphere, injecting oxygen and water or steam into said gasification sphere, said gasification sphere containing oxidizing the hydrocarbonaceous material to a synthesis gas, converting the synthesis gas into a hydrogen-rich stream in a shift reaction, and converting a first portion of the hydrogen-rich stream into the first liquefaction as process hydrogen; 3. The method of claim 2, wherein a second portion of said hydrogen-rich stream is passed as process hydrogen to said second coal liquefaction quantity. East said highly reactive coal is at least 30% more reactive than said less reactive coal under the same liquefaction conditions (E5-
3. The method of claim 2, wherein a 482 DEG C. (C5-900 DEG F.) liquid is produced. 5. The method of claim 2, wherein from about 1O to about 50% by weight of the first heavy fraction is passed through the second coal liquefier and the remainder is recycled to the first coal liquefier. 6. The method of claim 5, wherein about 15 to about 40% by weight of said first heavy fraction is passed through said second coal liquefier and the remainder is recycled to said first coal liquefier. 7. Passing the first reaction slurry through a first distillation zone to separate naphtha and middle distillate therefrom, passing the remaining portion through a first vacuum column, and passing the bottoms obtained from the first vacuum column into the first distillation zone. 3. The method of claim 2, wherein the slurry is mixed into a feed slurry for the second coal liquefaction sphere. 8 passing a portion of the second reaction slurry through a second distillation zone;
wherein the second reaction slurry is separated into a naphtha portion, a middle distillate portion and a bottoms portion; the bottoms portion is passed through a second vacuum column for separation into a heavy distillate portion and a second vacuum column bottoms; 3. The method of claim 2, wherein said second vacuum column bottoms forms a feed slurry to said gasification zone. 9. The method of claim 8, wherein a portion of the second reaction slurry is passed through the second fractionation and a second portion of the slurry is recycled to the second liquefaction sphere. 10 In each of the first and second coal liquefaction zones, the feed slurry is heated at about 427° to about 466°C (about 800° to
from about 70 to about 280 kgl at a temperature of about 870°F
Claim No. 1, wherein the reaction is carried out at a hydrogen partial pressure t' of from about 1000 to about 4000 psig, with a slurry residence time of from about 15 to about 120 minutes using a coal concentration of 20 to 50% by weight in the feed slurry. The method described in Section 2.