GB2032404A – Regeneration of Zinc Chloride Catalyst
– Google Patents
GB2032404A – Regeneration of Zinc Chloride Catalyst
– Google Patents
Regeneration of Zinc Chloride Catalyst
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Publication number
GB2032404A
GB2032404A
GB7841974A
GB7841974A
GB2032404A
GB 2032404 A
GB2032404 A
GB 2032404A
GB 7841974 A
GB7841974 A
GB 7841974A
GB 7841974 A
GB7841974 A
GB 7841974A
GB 2032404 A
GB2032404 A
GB 2032404A
Authority
GB
United Kingdom
Prior art keywords
zinc chloride
zinc
solids
catalyst
chloride
Prior art date
1978-10-26
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB7841974A
Other versions
GB2032404B
(en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
ConocoPhillips Co
Original Assignee
Conoco Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1978-10-26
Filing date
1978-10-26
Publication date
1980-05-08
1978-10-26
Application filed by Conoco Inc
filed
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Conoco Inc
1978-10-26
Priority to GB7841974A
priority
Critical
patent/GB2032404B/en
1980-05-08
Publication of GB2032404A
publication
Critical
patent/GB2032404A/en
1982-09-15
Application granted
granted
Critical
1982-09-15
Publication of GB2032404B
publication
Critical
patent/GB2032404B/en
Status
Expired
legal-status
Critical
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Classifications
C—CHEMISTRY; METALLURGY
C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
C10G1/08—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal with moving catalysts
C10G1/086—Characterised by the catalyst used
B—PERFORMING OPERATIONS; TRANSPORTING
B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
B01J27/28—Regeneration or reactivation
B01J27/32—Regeneration or reactivation of catalysts comprising compounds of halogens
Abstract
Improved rate of recovery of zinc values from the solids which are carried over by the effluent vapors from the oxidative vapor phase regeneration of spent zinc chloride catalyst is achieved by treatment of the solids with both hydrogen chloride and calcium chloride to selectively and rapidly recover the zinc values as zinc chloride. The process is particularly applicable to the regeneration of molten zinc chloride catalysts used in the hydrocracking of coaly solids and products derived from coaly solids.
Description
SPECIFICATION
Regeneration of Zinc Chloride Catalyst
This invention relates to the regeneration of spent zinc chloride catalyst. It is particularly applicable to the regeneration of molten zinc chloride catalyst used in the hydrocracking of coaly solids and products derived from coaly solids such as coal extracts or coal liquefaction products, but our invention is also applicable to the regeneration of other zinc chloride catalysts whose contaminants can be removed by the process of our invention.
A process for utilizing molten zinc chloride in such catalytic hydrocracking is described in
British Patent No. 1,095,851. As set forth in that patent, it was found that polynuclear hydrocarbons, even those which are nondistillable, may be readily converted in the presence of a large quantity of molten zinc chloride to low boiling liquids suitable for fuels, such as gasoline. The amount of zinc chloride which serves as catalyst is at least 1 5 weight percent of the inventory of hydrocarbonaceous material in the hydrocracking zone.To this amount of zinc chloride is added, in the case of nitrogen- and sulfur-containing feedstock, sufficient zinc chloride to remove reactive nitrogen and sulfur compounds in the feedstock, in accordance with the following equations:
(1) ZnCl2+H2S=ZnS+HCl (2) ZnCI2+NH3=ZnCI2 NH3 (3) ZnCl2. NH3+HCI=ZnCI2. NH4Cl In the case of a feedstock consisting of coal extract containing, for example, 1.5 percent N and 2 percent S, the amount of zinc chloride required to react stoichiometrically with the nitrogen and sulfur compounds would be 23 percent by weight of the feedstock.
The spent zinc chloride melt from the hydrocracking zone contains (in addition to zinc chloride) zinc sulfide (see Equation 1), ZnCl2. NH3 (see Equation 2), organic residue, and ash, as well as zinc oxide if the latter were used as an HCI acceptor. U.S. Patent 3,355,376 described two methods of regenerating the spent zinc chloride melt, both involving oxidation of the impurities, one in liquid phase and one in vapor phase.The reactions occurring in such oxidative regenerative processes are set forth in the following equations:
(4) NH3+3/4 02=1/2 N2+3/2 H2O
(5) ZnO+2 HCi=ZnCI2+H2O (6) ZnS+3/2 O2=ZnO+SO2
(7) C+O2=CO2
(8) C+1/2O2=CO In vapor phase oxidation, air is used to effect combustion of the organic residue, to thereby establish and maintain a temperature in the regenerator at which zinc chloride is vaporized.
The effluent zinc chloride vapors carry with them finely divided solids containing zinc values in the form of water-soluble and water-insoluble compounds, for example, “free” zinc oxide and zinc oxide chemically combined with acidic oxides such as silica which are present in the feedstocks to the hydro-cracking zone.
In our U.S. Patent Number 4,081,400, a process is described for recovery of zinc values which are entrained in the effluent zinc chloride vapors from a vapor phase oxidative regenerator.
The regenerative process therein described comprises four steps. In the first step, the spent zinc chloride melt from the hydrocracking zone is subjected to vapor phase oxidative treatment by combustion of the carbon and sulfur compounds, as well as any ammonia that may be present. In this step, the temperature is maintained at least high enough to assure vaporization of the zinc chloride. The effluent vapors contain finely divided solids composed of zinc oxide and zinc oxide complexes derived from the feedstock to the hydrocracking zone, some of which we now know to be water-soluble, and some water-insoluble, e.g. ZnO . SiO2. There generally is some residual organic residue in the entrained solids. The second step of the process consists of the separation of the zinc chloride vapors from the solids by any conventional means, generally a cyclone.The third step consists of the treatment of the separated solids with a hydrogen chloridecontaining gas under conditions favoring the reaction of zinc oxide and hydrogen chloride at a temperature sufficiently high to form zinc chloride in the vapor state. In the fourth step, vaporous zinc chloride is separated from the ash and condensed to the molten state for recycle to the hydro-cracking zone.
The primary object of the present inMention is to provide an improvement in the process for regenerating spent zinc chloride whereby the rate of recovery of zinc values from the solids entrained in the effluent zinc chloride vapors from the regenerator is increased.
The following patents were considered in the preparation of this specification:
Br. Patent 1,095,851
U.S. Patent 3,355,376
U.S. Patent 3,371,049
U.S. Patent 3,594,329
U.S. Patent 3,625,861
U.S. Patent 3,629,159
The regeneration process of our invention is an improvement and modification of the abovedescribed four-step process. We have observed that the rate of recovery of water-insoluble zinc values from the separated solids from the second step of said process is relatively slow. Our invention consists in treating said separated solids with both hydrogen chloride and calcium chloride, whereby the rate of recovery of the water-insoluble zinc values is improved.This behaviour may be explained by the following equation:
ZnO . SiO2+CaCI2=CaO SiO2+ZnCI2t Thus one aspect of our invention provides a process for regenerating a spent zinc chloride catalyst which contains zinc chloride, watersoluble and water-insoluble zinc values in solid form, and carbonaceous residue, said process comprising:
(a) subjecting said spent catalyst to vapor phase oxidative treatment whereby effluent zinc chloride vapors are produced which contain water-soluble and water-insoluble zinc values in solid form; (b) separating the zinc chloride vapors from said solids; (c) subjecting said separated solids to contact with both calcium chloride and with hydrogen chloride-containing gas under reaction conditions whereby the zinc values react therewith to form zinc chloride; and (d) recovering said zinc chloride in a substantially solids-free molten state.
The accompanying drawing is a schematic flowsheet of a preferred embodiment of the improved regeneration process of the present invention.
Referring to the drawing, spent zinc chloride melt is fed to a Combustor 10 through a conduit 1 2. The spent zinc chloride melt resulting from the hydrocracking of coal or coal derived products contains, in addition to zinc chloride, carbonaceous residue as well as ash, sulfur, and nitrogen components. The carbon, sulfur and nitrogen components in the spent catalyst are oxidized by air fed to the Combustor via a conduit
14. The air preferably contains a low concentration of HCI to aid in preventing hydrolysis of zinc chloride by steam. The combustion conducted in the Combustor may be either with less than or greater than, the stoichiometric amount of air. In the former case, fuel gas will be produced; in the latter case, flue gas.
Heat is generated in the Combustor by oxidation of the carbon contained in the spent melt, and is sufficient to maintain the temperature in the Combustor above the vaporization temperature of zinc chloride. The latter, in vapor form, together with steam, non-condensable gases, N2, CO and CO2, unreacted HCI, and entrained solids, is withdrawn from the
Combustor 10 through a conduit 1 6 to a hot
Separator 18 which is any cyclone commonly used for the separation of gases and solids at high temperature. In this instance, the temperature of the cyclone is not permitted to drop below the condensation point of zinc chloride.
Zinc chloride and water vapors and noncondensable gases CO, CO2, N2 and HCI are withdrawn from the Separator 1 8 through a conduit 20 to a condenser 22 for selective condensation after passing through a pre-cooler 21. Zinc chloride condensate in molten form is discharged from the condenser 22 through a conduit 24 for return to the hydrocracking zone (not shown). The non-condensable gases are withdrawn from the condenser through conduit 26 to a suitable HCI recovery zone 28 from which
HCI is recovered through conduit 30 for reuse in the process. A gas is withdrawn from the HCI recovery zone through conduit 32 which is a low sulfur fuel gas whenever sub-stoichiometric quantities of air are used in Combustor 10.
A typical analysis of the separated solids from
Separator 18 is as follows:
Table I
Analysis of Cyclone Ash (% by weight)
Zn (in the form of water
soluble zinc compounds) 2.94
Zn (in the form of water
insoluble zinc compounds) 4.54
Cl 4.92
H 0.08
C 0.09
S 0.37
Na20 0.10 K20 0.03
CaO 11.40
MgO 4.45
Fe203 3.90
TiO2 0.94
SiO2 42.86 AI2O3 18.41
95.03* *Other compounds were obviously present that could not be readily determined.
The solids discharged from the hot Separator
18 are conducted by a conduit 34 to a premixer and preheater 35. CaCI2 in finely divided form is introduced into conduit 34 from a hopper 36. The amount is preferably twice the amount needed to react with the water-insoluble zinc compounds, as determined by analysis. The solids are mixed with a stream of HCI-containing gas introduced through a conduit 38. The gas may conveniently be air or combustion gases. The mixture of gases and entrained solids is transferred to a second
Combustor 40 where the zinc oxide and zinc
oxide complexes are converted to zinc chloride by
reaction with HCI and CaCI2. The temperature of the Combustor is maintained above the
vaporization temperature of zince chloride, for
example 17000 F, by the oxidation of carbon in
the case where oxygen is contained in the HCI
containing gas. The carbon is that contained in the unconsumed organic residue carried over from the first Combustor or is added as required to the second Combustor expressly for that
purpose. Such added or supplemental carbon may
be in the form of coal.
Zinc chloride vapors, ash and non-condensable
gases are withdrawn from the Combustor 40
through a conduit 42 to a hot cyclone Separator
44 where the ash containing added calcium is
rejected through a line 46. The vapors and gases
pass through a pre-cooler 48 in a conduit 50 to a
condenser 52 adapted to selectively condense
zinc chloride in molten form. The molten zinc
chloride is withdrawn through line 54 for recycle.
The non-condensable gas is withdrawn through a conduit 56 to a suitable HCI recovery zone 58 for recovery of HCI through a conduit 60. The HCI-free gas, together with any sulfur-rich gas withdrawn from conduit 32 through a conduit 61, is conducted through a conduit 62 to an SO2- reduction zone 64 for conversion of SO2 in the gas to elemental sulfur. The amount of SO2 in conduit 32 and in conduit 62 is a function of the amount of air used in Combustor 10, the larger the amount of air, the greater the amount of SO2 in conduit 32, and conversely the smaller the amount, the larger the amount in conduit 62. In either case, it is desirable to recover such SO2 as sulfur. The CO and H2 contained in the gas provides a suitable source of reducing agent for
SO2 reduction. The sulfur product is recovered through a conduit 66. The remaining gas may be, incinerated in an incinerator 67 to remove residual sulfur compounds.
In the foregoing specification, the principle, preferred construction and mode of operation of the invention have been explained and what is considered to represent its best embodiment has been illustrated and described. However, it should be understood that, within the scope of the appended claims, the invention may be practised otherwise than as specifically illustrated and described.
Claims (8)
Claims
1. A process for regenerating a spent zinc chloride catalyst which contains zinc chloride, water-soluble and water-insoluble zinc values in solid form, and carbonaceous residue, said process comprising:
(a) subjecting said spent catalyst to vapor phase oxidative treatment whereby effluent zinc chloride vapors are produced which contain water-soluble and water-insoluble zinc values in solid form; (b) separating the zinc chloride vapors from said solids; (c) subjecting said separated solids to contact with both calcium chloride and with hydrogen chloride-containing gas under reaction conditions whereby the zinc values react therewith to form zinc chloride; and (d) recovering said zinc chloride in a substantially solids-free molten state.
2. A process according to claim 1 wherein said spent zinc chloride catalyst has been used as a molten catalyst to catalyze the hydrocracking of coaly solids or products derived therefrom.
3. A process according to claim 1 or 2 wherein said vapor phase oxidative treatment is performed in a combustor, heat generated by oxidation of carbon in said spent catalyst being sufficient to maintain the temperature in the combustor above the vaporization temperature of zinc chloride.
4. A process according to any of the preceding claims wherein there is used about twice the amount of calcium chloride needed to react with said water-insoluble zinc values.
5. A process accordng to any of the preceding claims wherein said step (c) is-performed in a combustor maintained above the vaporization temperature of zinc chloride.
6. A process according to claim 1, substantially as described herein.
7. A process for regenerating a spent zinc chloride catalyst, substantially as illustrated in the accompanying drawing.
8. A process for hydrocracking coaly solids or products derived therefrom in the presence of a molten zinc chloride catalyst, wherein spent catalyst is regenerated by the process of any of claims 1-7.
GB7841974A
1978-10-26
1978-10-26
Regeneration of zinc chloride catalyst
Expired
GB2032404B
(en)
Priority Applications (1)
Application Number
Priority Date
Filing Date
Title
GB7841974A
GB2032404B
(en)
1978-10-26
1978-10-26
Regeneration of zinc chloride catalyst
Applications Claiming Priority (1)
Application Number
Priority Date
Filing Date
Title
GB7841974A
GB2032404B
(en)
1978-10-26
1978-10-26
Regeneration of zinc chloride catalyst
Publications (2)
Publication Number
Publication Date
GB2032404A
true
GB2032404A
(en)
1980-05-08
GB2032404B
GB2032404B
(en)
1982-09-15
Family
ID=10500589
Family Applications (1)
Application Number
Title
Priority Date
Filing Date
GB7841974A
Expired
GB2032404B
(en)
1978-10-26
1978-10-26
Regeneration of zinc chloride catalyst
Country Status (1)
Country
Link
GB
(1)
GB2032404B
(en)
1978
1978-10-26
GB
GB7841974A
patent/GB2032404B/en
not_active
Expired
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Publication number
Publication date
GB2032404B
(en)
1982-09-15
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Legal Events
Date
Code
Title
Description
1983-07-27
PCNP
Patent ceased through non-payment of renewal fee
