Abstract:
A process for the synthesis of liquid hydrocarbon fuels and hydrogen based on the use of sulfur as an oxidant.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention disclosed and embodied herein relates to the synthesis of liquid hydrocarbon fuels and hydrogen from coal or natural gas or related materials. The invention further relates to a thermochemical cycle based on the use of sulfur as an oxidant, the recovery of sulfur and hydrogen from by-product hydrogen sulfide and to a process wherein said synthesis is carried out in the presence of a ZSM-5 type catalyst. 
     2. Description of the Prior Art 
     It is known that aliphatic organic compounds containing oxygen, sulfur, nitrogen and/or halogen constituents may be converted to aromatic hydrocarbons in commercially desirable yields in the presence of zeolites; see U.S. Pat. No. 3,894,103. It is also known that synthesis gas, i.e., mixed carbon monoxide and hydrogen, can be catalytically converted into liquid hydrocarbon fuels such as gasoline boiling range products. However, the products of such reactions are predominantly paraffinic and the product is unsuited for use in modern internal combustion engines; see U.S. Pat. No. 3,894,102. U.S. Pat. No. 3,894,102 discloses a process wherein hetero-organic compounds, RX, where R is an aliphatic moiety and X is a heteroatom such as sulfur, nitrogen, halogen or oxygen may be converted to aromatic hydrocarbons by contacting such compounds with an alumino-silicate zeolite. 
     Coal shale oil and/or tar sands are some of the raw materials used to provide materials for hydrocarbon conversion but to applicant&#39;s knowledge heretofore such technology unlike the present invention has used oxygen rather than sulfur as the oxidant. 
     SUMMARY OF THE INVENTION 
     A novel process for the synthesis of liquid fuels from methane or natural gas, coal and/or related materials is disclosed herein. Further, an economical means of producing hydrogen is also provided. The aforementioned process offers an attractive alternative to prior art methods of coal gasification and CH 4  steam reforming. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Liquid hydrocarbon fuels and H 2  are co-produced according to the novel following series of integrated steps: 
     
         ______________________________________From coalC + 2S → CS.sub.2 [1]CS.sub.2 + H.sub.2 O → COS + H.sub.2 S                    [2]COS → 1/2CO.sub.2 + 1/2CS.sub.2                    [3]1/2CS.sub.2 + 3/2H.sub.2 → 1/2[CH.sub.2 ] + H.sub.2 S                    [4]H.sub.2 S + n/2 M → M.sub.n/2 S + H.sub.2                    [5]M.sub.n/2 S → n/2 M + S                    [6]C + H.sub.2 O → 1/2[CH.sub.2 ] + 1/2CO.sub.2 + 1/2H.sub.2                    AFrom CH4CH.sub.4 + 4S → CS.sub.2 + 2H.sub.2 S                    [7]CS.sub.2 + 3H.sub.2 → [CH.sub.2 ] + 2H.sub.2 S                    [4]4H.sub.2 S → 4H.sub.2 + 4S                    [5] +  [6]CH.sub.4 → [CH.sub.2 ] + H.sub.2                    B______________________________________ 
    
     Reactions 1, 3 and 7 are, as is readily known to one of ordinary skill in the art, well known, M in the above recited steps 5 and 6 is a metal such as, Fe, Co, Ni or a Group V-A metal such as bismuth, or a Group VI-B metal such as Mo, or any combination thereof. 
     It is further noted that reactions 4 and 5 set forth above may be carried out as described in one step or in two steps as follows: ##STR1## 
     The inventive aspect of the present invention is a combination of the ordered sequential reactions utilized to produce the bottom line reactions A and B and the specific manner, i.e. such as molar ratio, etc., in which the reactants are utilized therein. 
     Usually in accordance herewith the above reactions [4] and [9] take place in the presence of a zeolite type catalyst. The zeolites particularly useful herein include ZSM-5, ZSM-11, ZSM-12, ZSM-35 and ZSM-38. These zeolites may be base exchanged, contain hydrogen or ammonium ions or a metal cation. Examples of suitable metals include Co, Co/Mo, Zn, Zn/Pd, Ni, Ni/W, Ni/Mo, etc. Generally speaking, most Group II and Group III metals of the Periodic Table may be used. A preferred typical catalyst is CoHZM-5. 
     U.S. Pat. No. 3,702,886 which describes and claims ZSM-5; U.S. Pat. No. 3,709,979 which describes and claims ZSM-11; West German Offenlegungsschrift No. 2,213,109 which describes ZSM-12; U.S. Pat. No. 4,016,245 which describes ZSM-35; and U.S. Pat. No. 4,046,859 which describes ZSM-38 are incorporated herein in their entirety. 
     The practice of the novel process of the present invention is particularly described below in preferred embodiments. 
     
                       TABLE______________________________________     EXAMPLE 1 EXAMPLE 2______________________________________Reaction ConditionsCS.sub.2, LHSV        1           1H.sub.2, GHSV       400         400T, °F.       900         900P, psig     250         250Catalyst    HZSM-5            50% HZSM-5/Al.sub.2 O.sub.3                         50% Co/SiO.sub.2                         (Harshaw Co-401)CS.sub.2 Conversion, %       25.6        40.3HC, wt. %C.sub.1     52.4        44.7C.sub.2     9.2         6.1C.sub.2     1.9         --C.sub.3     3.0         3.7C.sub.3     0.3         0.1i -C.sub.4  0.2         0.2 -n C.sub.4 0.2         0.3C.sub.4     --          --C.sub.5.sup.+ nonaro       --          trA.sub.6     1.4         2.6A.sub.7     5.9         7.7A.sub.8     8.2         9.5A.sub.9     4.6         18.1A.sub.10    0.3         3.2A.sub.11.sup.+       12.4        3.8______________________________________ 
    
     The reaction parameters for reaction [4] may vary from 400° F. to 1200° F. and 0 psig to 2000 psig, for reaction [5], from ambient temperature to about 500° F. and 0 psig to 2000 psig, and for reaction [6] from 500° F. to about 2000° F. 
     The preferred reaction conditions for reactions 4, 5 and 6 are as follows: 
     for reaction [4]: 
     700°-1000° F. 
     25-50 psig 
     for reaction [5]: 
     25°-400° F. 
     50-1500 psig 
     for reaction [6]: 
     600°-1500° F. 
     The methane and the coal were obtained from commercial sources. 
     The embodiments and details outlined above are noted hereinabove solely for the purpose of illustrating the invention and, as is readily apparent to one of ordinary skill in the art variations and departure can be made therefrom within the scope of the invention.