FORMING LIGHT HYDROCARBONS

Abstract

Form liquid product stream that has a C.sub.13 to C.sub.20 hydrocarbon content of less than 5.0 wt % based upon a total weight of the liquid product stream via a process that includes contacting synthesis gas with a sulfurized Zeolite Socony Mobil-5 catalyst. The sulfurized Zeolite Socony Mobil-5 catalyst can include ZSM-5, cobalt, an alkali metal, sulfur, and a reduction promoter.

Claims

1. A process for producing a liquid product stream that has a C.sub.13 to C.sub.20 hydrocarbon content of less than 5.0 wt % based upon a total weight of the liquid product stream, the process comprising: contacting synthesis gas with a sulfurized Zeolite Socony Mobil-5 catalyst, wherein the sulfurized Zeolite Socony Mobil-5 catalyst includes cobalt and a sulfur doped Zeolite Socony Mobil-5 support, with the sulfur being incorporated via sulfate ions, the cobalt being present in an amount within a range of from 1 to 25 wt % based upon a dry weight of the sulfurized Zeolite Socony Mobil-5 catalyst, the sulfur being present in an amount within a range of from 0.01 to 1.00 w t%, based upon a dry weight of the sulfurized Zeolite Socony Mobil-5 catalyst, the conditions consisting essentially of a temperature within a range of from 150 to 300° C., a pressure within a range of from 5 to 40 bar, and a gas hourly space velocity within a range of from 100 to 10000 h.sup.−1.

2. The process of claim 1, wherein the sulfurized Zeolite Socony Mobil-5 catalyst includes an alkali metal.

3. The process of claim 2, wherein the alkali metal is within a range of from 0.01 to 4.50 wt % based upon a dry weight of the sulfurized ZSM-5 catalyst.

4. The process of claim 2, wherein the alkali metal is sodium.

5. The process of claim 1, wherein the sulfurized Zeolite Socony Mobil-5 catalyst includes a reduction promoter.

6. The process of claim 5, wherein the reduction promoter is within a range of from 0.01 to 5.00% based upon a dry weight of the sulfurized ZSM-5 catalyst.

7. The process of claim 6, wherein the reduction promoter is ruthenium.

8. The process of claim 1, wherein the liquid product stream has a C.sub.5-C.sub.12 hydrocarbon content of at least 25 wt % based upon a total weight of the liquid product stream.

Description

EXAMPLES

[0022] Materials include: mordenite (HSZ-690 HOA, available from Tosoh Corporation); ZSM-5 (CBV8014, aluminosilicate zeolite, available from Zeolyst International); cobalt nitrate hexahydrate (cobalt precursor, ACS reagent>98%, available from Sigma Aldrich); ruthenium nitrosyl nitrate solution diluted in nitric acid (reduction promoter precursor, available from Sigma Aldrich); sodium sulfate (ACS reagent>99%, anhydrous, available from Sigma Aldrich); ammonium sulfate (available from Sigma Aldrich); and sodium nitrate (available from Sigma Aldrich).

[0023] Form sulfurized ZSM-5 catalyst-1 as indicated. Press ZSM-5 into a one-inch diameter die to form a pellet, crush the pellet to form a powder, and sieve the powder. Collect a 20-40 mesh fraction to obtain a ZSM-5 support. Calcine the ZSM-5 support in air at 500° C. for four hours to obtain a calcined. ZSM-5 support (4 grams (g)). Prepare an ammonium sulfate solution (ammonium sulfate (0.0378 g) dissolved in de-ionized water (1.4 mL).) Impregnate the ammonium sulfate solution onto the ZSM-5 support to provide 0.2 wt % sulfur; calcine in air for four hours at 500° C. to provide a sulfurized ZSM-5 support. Prepare a cobalt precursor solution (20 milliliter (mL)) having a cobalt concentration of 2 moles/liter (mol/L) by dissolving cobalt nitrate hexahydrate (11.6 g) in de-ionized water; prepare the precursor solution by mixing in a vial 4.7 mL of the cobalt precursor solution of the ruthenium nitrosyl nitrate solution (0.59 mL) and de-ionized water (2.2 mL). impregnate the precursor solution (2 mL) onto the sulfurized ZSM-5 support; dry for two hours at 100° C. Repeat the impregnation and drying steps two additional times; then calcine in air for two hours at 300° C. to obtain the sulfurized ZSM-5 catalyst-1.

[0024] Form sulfurized ZSM-5 catalyst-2 as sulfurized ZSM-5 catalyst-1, with that changes that prior to the impregnation with the precursor solution, impregnate sodium nitrate solution (0.044 g dissolved in 1.4 ml de-ionized water) to provide 0.3 wt % sodium and calcine in air for four hours at 500° C.

[0025] Form sulfurized ZSM-5 catalyst-3 as sulfurized ZSM-5 catalyst-1, with that changes that prior to the impregnation with the precursor solution, impregnate sodium sulfate solution (0.0824 g dissolved in 1.4 mL of de-ionized water) to provide 0.3 wt % sodium and calcine in air for four hours at 500° C.

[0026] Form mordenite catalyst-A as ZSM-5 catalyst-1, with that changes that HSZ-690 HOA is utilized rather than ZSM-5; prior to the impregnation with the precursor solution, impregnate sodium sulfate solution (0.0824 g of Na.sub.2SO.sub.4 dissolved in 1.4 mL de-ionized water) to provide 0.3 wt % sodium and 0.21 wt % sulfur and calcine in air for four hours at 500° C.

[0027] Form ZSM-5 catalyst-B as ZSM-5 catalyst-1, with that changes that prior to the impregnation with the precursor solution, impregnate sodium nitrate solution (0.044g dissolved in 1.4 mL of de-ionized water) to provide 0.3 wt % sodium; calcine in air for four hours at 500° C.

[0028] Determine composition of the catalysts by X-ray fluorescence analysis; weight percents are shown in Table 1.

TABLE-US-00001 TABLE 1 Co Ru Na S Catalyst (wt %) (wt %) (wt %) (wt %) Sulfurized ZSM-5 13.80 0.20 0.00 0.20 catalyst-1 Sulfurized ZSM-5 13.80 0.20 0.30 0.25 catalyst-2 Sulfurized ZSM-5 13.00 0.20 0.27 0.16 catalyst-3 Mordenite catalyst-A 12.80 0.20 0.30 0.20 ZSM-5 catalyst B 13.70 0.20 0.37 0.00

Example (Ex) 1

[0029] Mix sulfurized ZSM-5 catalyst-1 (1 gram (g)) with silicon carbide (3 milliliters (mL)); load the mixture into a tubular reactor. Purge the reactor system with nitrogen (50 milliliters per minute (mL/min)) and heat the reactor to 150° C. at a rate 5° C/min. Stop nitrogen flow and introduce hydrogen (50 mL/min) at 150° C. and one bar for one hour. Maintain hydrogen flow and increase temperature to by 1° C./minute to 250° C. and maintain for 10 hours. Reduce temperature to 180° C. Stop hydrogen flow and add a flow including carbon monoxide (30 mole percent), hydrogen (60 mole percent), and helium (10 mole percent) to provide a gas hourly space velocity of 1500 h.sup.1. Pressurize to 10 bar and increase temperature to desired reaction temperature (220° C.). Stabilize the reactor system for 24 hours then adjust flows to achieve a different gas hourly space velocity (1000 h.sup.−1) for a desired time on stream and produce liquid product stream. Send reactor effluent to a knock out vessel heated to 170° C., add nitrogen (100 mL/min) to flow exiting the knock out vessel. Analyze with an Agilent 7890A Gas Chromatography system equipped with a 2D analysis system to analyze and quantify C.sub.7-C.sub.30 hydrocarbons and a 1D system to analyze C.sub.1-C.sub.10 hydrocarbons to determine carbon monoxide conversion and product distribution. Flush the reactor system with nitrogen flow and cool down the reactor and knock out vessel. Drain any wax from the knock out vessel by heating the knock out vessel in an oven at 100° C. to melt the wax. Calculate distribution of products independently, i.e. without normalization. Product distribution shown in Table 4.

Exs 2-5

[0030] Repeat Ex 1, with any changes indicated in Table 2. Product distribution is shown in Table 4.

Comparative Examples (Com Ex) A-C

[0031] Repeat Ex 1, with any changes indicated in Table 3. Product distribution is shown in Table 5.

TABLE-US-00002 TABLE 2 Gas Hourly Space Time on Temperature Pressure Velocity Stream Example Catalyst (° C.) (bar) (h.sup.−1) (h) Ex 1 Sulfurized 220 10 1000 95 ZSM-5 catalyst-1 Ex 2 Sulfurized 220 10 1500 37 ZSM-5 catalyst-1 Ex 3 Sulfurized 220 10 1500 67 ZSM-5 catalyst-3 Ex 4 Sulfurized 220 10 1200 96 ZSM-5 catalyst-3 Ex 5 Sulfurized 220 10 1500 39 ZSM-5 catalyst-3

TABLE-US-00003 TABLE 3 Gas Hourly Space Time on Comparative Temperature Pressure Velocity Stream Example Catalyst (° C.) (bar) (h.sup.−1) (h) Com Ex A Mordenite 220 10 900 92 catalyst-A Com Ex B Mordenite 220 10 1500 40 catalyst-A Com Ex C ZSM-5 220 10 1500 67 catalyst B

[0032] Calculate carbon monoxide (CO) conversion by the following formula:

[00001]$\mathrm{CO}.Math..Math.\mathrm{conversion}=\left(1-\frac{n_{\mathrm{CO},\mathrm{in}}-n_{\mathrm{CO},\mathrm{out}}}{n_{\mathrm{CO},\mathrm{in}}}\right)\times 100.Math.\%$

where nco.sub.in and nco.sub.out are moles of CO fed to the reactor and exiting the reactor respectively.

[0033] Calculate C.sub.5-C.sub.12 hydrocarbon % by the following formula:

[00002]$C_5-C_{12}.Math..Math.\mathrm{hydrocarbon}.Math..Math.\%=\frac{\underset{i=5}{\overset{12}{.Math.}}.Math..Math.S_{n-C_i}}{\underset{i=5}{\overset{12}{.Math.}}.Math..Math.S_{C_i}}\times 100.Math.\%$

where S.sub.n-Ci is the selectivity of hydrocarbons having a carbon number i, where, i is from 5 to 12, and S.sub.Ci is the selectivity of alkanes or olefins having a carbon number i, where, i is from 5 to 12.

[0034] Calculate C.sub.13-C.sub.20 hydrocarbon % by the following formula:

[00003]$C_{13}-C_{20.Math.}.Math.\mathrm{hydrocarbon}.Math..Math.\%=\frac{\underset{i=13}{\overset{20}{.Math.}}.Math..Math.S_{n-C_i}}{\underset{i=13}{\overset{20}{.Math.}}.Math..Math.S_{C_i}}\times 100.Math.\%$

where S.sub.n-Ci is the selectivity of hydrocarbons having a carbon number i, where, i is from 13 to 20, and S.sub.Ci is the selectivity of alkanes or olefins having a carbon number i, where, i is from 13 to 20.

[0035] Calculate product selectivities independently, meaning apply no normalization. This is represented by the following formula:

[00004]$S_{\mathrm{Ci}}.Math.\%=\frac{i\times n_{\mathrm{Ci}}}{n_{\mathrm{CO},\mathrm{in}}-n_{\mathrm{CO},\mathrm{out}}}\times 100.Math.\%$

where S.sub.Ci is selectivity to a hydrocarbon with carbon number i, n.sub.Ci is the amount of moles formed of this hydrocarbon, and n.sub.CO,in and n.sub.CO,out are the moles of CO fed to the reactor and exciting the reactor respectively.

TABLE-US-00004 TABLE 4 Carbon Monoxide Solid Wax (greater Example Conversion (%) C.sub.1 (%) C.sub.2-C.sub.4 (%) C.sub.5-C.sub.12 (%) C.sub.13-C.sub.20 (%) C.sub.21-C.sub.30 (%) than C.sub.30) Ex 1 20 21 22 33 0 0 None detected Ex 2 21 19 21 42 0 1 None detected Ex 3 30 22 24 51 2 2 None detected Ex 4 25 21 23 48 0 2 None detected Ex 5 27 20 22 55 7 2 None detected

TABLE-US-00005 TABLE 5 Comparative Carbon Monoxide Solid Wax (greater Example Conversion (%) C.sub.1 (%) C.sub.2-C.sub.4 (%) C.sub.5-C.sub.12 (%) C.sub.13-C.sub.20 (%) C.sub.21-C.sub.30 (%) than C.sub.30) Com Ex A 18 19 10 34 16 4 Some detected Com Ex B 11 19 11 39 17 4 Some detected Com Ex C 35 18 13 49 14 3 Some detected

[0036] The data in Table 4 show that the processes disclosed herein form C.sub.5-C.sub.12 hydrocarbons. The data in Table 4 show that each of Examples 1-5 produces a liquid product stream that has a C.sub.13 to C.sub.20 hydrocarbon content of less than 5 wt %. In contrast to the data in Table 4, the data in Table 5 show that each of Comparative Examples A-C produces a liquid product stream that has a C.sub.13 to C.sub.20 hydrocarbon content equal to or greater than 14 wt %. Additionally, the data in Table 4 and Table 5 show that the product stream for each of Examples 1-5 has an advantageously reduced a C.sub.21 to C.sub.30 selectivity as compared respectively to each of Comparative Examples A-C. Further, the data in Table 4 and Table 5 show that the product stream for each of Examples 1-5 did not include detectable solid waxes. In contrast to Examples 1-5, each of Comparative Examples A-C produces a detectable amount of solid wax.