METHOD FOR ACTIVATING A CATALYST, REACTOR, AND METHOD OF OBTAINING HYDROCARBONS IN FISCHER-TROPSCH PROCESS

Abstract

The invention relates to Fischer-Tropsch synthesis in a compact version. A compact reactor comprises a housing, rectangular reaction channels inside the housing, which are filled with a cobalt catalyst, synthesis gas injection nozzles in the number determined by the ratio of the number of channels to the number of synthesis gas injection nozzles, an input and output nozzle for heat transfer medium on which a pressure controller installed, and an assembly for withdrawing synthetic hydrocarbons. The cobalt catalyst is activated by passing hydrogen through it. Synthetic hydrocarbons are produced by passing synthesis gas through the reaction channels filled with the activated cobalt catalyst. The space velocity of synthesis gas is increased every 300-500 h, followed by returning to the initial process conditions. This provides a high-molecular-weight hydrocarbon output per unit mass of the reactor.

Claims

1. A compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process, comprising a housing with reaction channels filled with a cobalt catalyst, wherein the channels have a thickness of 1 to 5 mm and a rectangular cross section; synthesis gas injection nozzles; input and output nozzles for heat transfer medium; and an assembly for withdrawing synthetic hydrocarbons, wherein the reactor is characterized in that a pressure controller is installed on the output nozzle for heat transfer medium, the outer surface of the wall of the reaction channels with the catalyst has a roughness of 1.6 to 25 m, a distance between the nearest reaction channels is 1 to 5 mm, a thickness of the wall of the reaction channel is 1 to 3 mm, a width-to-thickness ratio of the reaction channel is 2 to 100, and a height-to-thickness ratio of the reaction channel is from 20 to 2000, wherein a ratio of the number of reaction channels to the number of synthesis gas injection nozzles is from 1 to 50.

2. The reactor according to claim 1, characterized in that a ratio of the total cross-sectional area of the reaction channels to the cross-sectional area of the housing is from 0.17 to 0.89 to provide the boiling of water in a pool boiling mode.

3. A method for activating a catalyst in the compact reactor for the production of synthetic hydrocarbons in Fischer-Tropsch process according to claim 1, characterized in that hydrogen is passed through the reaction channels filled with the cobalt catalyst at a space velocity of 1000 to 30000 h.sup.1, a temperature of 200 to 280 C., and a pressure of 0.1 to 3.0 MPa for 1 to 48 h.

4. A method of carrying out a Fischer-Tropsch process to produce synthetic hydrocarbons in the compact reactor according to claim 1, characterized in that synthesis gas with an H.sub.2/CO ratio of 2.22 to 2.60 is fed at a space velocity of 10000 to 19000 h.sup.1 to reaction channels of the compact reactor filled with the cobalt catalyst activated according to claim 3, wherein every 300-500 hours the synthesis gas space velocity is increased up to 20000-30000 h.sup.1 by 1-5 h, followed by returning to the initial conditions of the process.

5. The method according to claim 4, characterized in that the Fischer-Tropsch process is carried out at a temperature of 210-260 C. and a pressure of 1.0 to 3.0 MPa.

Description

[0023] FIG. 1 shows a longitudinal section of the reactor.

[0024] FIG. 2 shows an end view of the reactor.

[0025] Under boiling, the temperature in the cooling jacket is determined by the pressure and remains constant, strictly ensuring an isothermal mode in the reaction channels.

[0026] The reactor consists of rectangular minichannels (1) having a thickness of 1 to 5 mm and a width-to-thickness ratio of from 2 to 100, and a height-to-thickness ratio of from 20 to 2000. The thickness of the wall of the reaction channels is from 1 to 3 mm. The outer surface of the channels with a catalyst has a roughness of 1.6 to 25 m. The reaction channels are placed in a housing (2) having a cross section of any shape, for example, round, rectangular, square. The ratio of the total cross-sectional area of the channels to the cross-sectional area of the housing is from 0.17 to 0.89 to ensure the boiling of water in the pool boiling mode. The temperature profile in the cooling jacket of the catalytic zone of the reactor is controlled by thermocouples placed in a thermocouple channel (3) disposed between the reaction channels in the cooling jacket coaxially with the central axis of the reactor. The isothermal mode of the Fischer-Tropsch process in the reaction channels is maintained by boiling water in the cooling jacket in the pool boiling mode. The temperature is determined by the pressure of water in the jacket and remains constant, strictly ensuring the isothermal mode in the reaction channels. Water is fed into the reactor-cooling jacket through an input nozzle (4) and discharged through an output nozzle (5), on which a pressure controller (not shown) is installed to control the pressure of water in the jacket. A uniform flow distribution of feedstock through the channels is provided by several injection nozzles (6), a number of which is determined by the ratio of a number of channels to a number of nozzles in the range from 1 to 50. Products are withdrawn through a withdrawal nozzle (7). Reaction minichannels (1) are evenly spaced in the tubular space of the cooling jacket relative to the central axis of the reactor with a distance between the nearest channels of from 1 to 5 mm, for example, as shown in FIG. 2. At the ends, the body of the cooling jacket is closed by flanges.

[0027] For use of the reactor according to the present invention in a method for producing synthetic hydrocarbons in a Fischer-Tropsch process in a compact version, a cobalt catalyst is loaded into the reaction minichannels for conducting the Fisher-Tropsch process in a compact version. The cobalt catalyst is pre-activated in situ in the Fischer-Tropsch synthesis reactor in a hydrogen stream at a space velocity of 1000-30000 h.sup.1, a temperature of 200-280 C., and a pressure of 0.1-3.0 MPa.

[0028] The production of synthetic hydrocarbons in the Fischer-Tropsch process in a compact version in the minichannel compact reactor according to the present invention is carried out in the presence of an in situ activated cobalt catalyst for Fischer-Tropsch synthesis, which is suitable for the use in a compact version at its maximum productivity rate under conditions selected from the following ranges: an H.sub.2/CO ratio of 2.22 to 2.60, a temperature of 210-260 C., a pressure of 1.0-3.0 MPa, and a synthesis gas feed space velocity of 10000-20000 h.sup.1. When the method for producing synthetic hydrocarbons is carried out in a compact version, the process is performed under conditions of the maximum productivity, according to which, every 300-500 hours, the space velocity is increased up to 20000-30000 h.sup.1 by 1-5 h at the temperature, pressure, and H.sub.2/CO ratio, which correspond to the conditions of maximum productivity, followed by returning to the initial conditions of the synthesis.

[0029] The maximum performance conditions mean herein a combination of the temperature, pressure, space velocity, and H.sub.2/CO ratio in synthesis gas, which provides the maximum productivity of the designed reactor after activation in the developed activation mode at a catalyst productivity of more than 1200 kg C.sub.5+/m.sup.3.sub.cat.Math.h and a conversion of CO of at least 69%.

[0030] The operating efficiency of the compact minichannel reactor is evaluated on the results of the study of characteristics of a cobalt catalyst when a Fischer-Tropsch process is carried out at a high productivity rate.

[0031] The CO conversion is calculated according to the following equation:

[00001]$K_{\mathrm{CO}}=\frac{m_{\mathrm{CO}}^{\mathrm{in}}-m_{\mathrm{CO}}^{\mathrm{out}}}{m_{\mathrm{CO}}^{\mathrm{in}}}.Math.100.Math.\%,$

wherein

[0032] m.sub.CO.sup.in is the weight of carbon monoxide in 1 m.sup.3 of gas injected into the reactor;

[0033] m.sub.CO.sup.out is the weight of carbon monoxide in 1 m.sup.3 of gas discharging from the reactor.

[0034] The selectivity for liquid hydrocarbons is calculated according to the following equation:

[00002]$S_{C_{5+}}=\frac{\frac{m_C}{C_{5+}}}{\frac{m_C}{{\mathrm{CO}}_{\mathrm{in}}}-\frac{m_C}{{\mathrm{CO}}_{\mathrm{out}}}}.Math.100.Math.\%,$

wherein

[00003]$\frac{m_C}{C_{5+}}$

is the weight of carbon contained in liquid hydrocarbons resulting from the synthesis in time ;

[00004]$\frac{m_C}{{\mathrm{CO}}_{\mathrm{in}}}$

is the weight of carbon contained in carbon monoxide injected into the reactor in time ;

[00005]$\frac{m_C}{{\mathrm{CO}}_{\mathrm{out}}}$

[0035] is the weight of carbon contained in carbon monoxide discharging from the reactor in time .

[0036] The catalyst productivity is calculated according to the following equation:

[00006]$P_{\mathrm{cat}}=\frac{m_{C_{5+}}}{t.Math.V_{\mathrm{out}}},$

wherein

[0037] m.sub.C.sub.5+ is the weight of high molecular weight hydrocarbons resulting from Fischer-Tropsch synthesis for time , kg;

[0038] is the duration of the synthesis, h;

[0039] V.sub.cat is the volume of the catalyst loaded into the Fischer-Tropsch synthesis reactor, m.sup.3.

[0040] The output per unit mass of the reactor is calculated according to the following equation:

[00007]$P_r=\frac{P_{\mathrm{cat}}.Math.V_{\mathrm{cat}}.Math.24.Math.1000}{m_r},$

wherein

[0041] m.sup.r is the weight of the Fischer-Tropsch synthesis reactor, kg.

[0042] The content of the initial and resulting substances in the gases escaping from the Fischer-Tropsch synthesis reactor can be determined by any known method, for example, by gas chromatography.

EMBODIMENTS OF THE INVENTION

[0043] The Fischer-Tropsch process in a compact version can be performed in accordance with the following examples.

Example 1

[0044] The structure of a compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process includes a housing containing four reaction channels filled with a cobalt catalyst containing 44.0 wt. % Co and 56.0 wt. % ZrO.sub.2; wherein the reaction channels has a thickness of 4 mm, a width-to-thickness ratio of 10, and a height-to-thickness ratio of 2000 and are placed in an outer housing sealed with two flange connections. The thickness of the wall of the reaction channel is 1.5 mm. The distance between the nearest reaction channels is 3 mm. The ratio of the total cross-sectional area of the channels to the cross-sectional area of the housing is 0.17. To obtain a uniform flow distribution of feedstock, the ratio of the number of channels to the number of synthesis gas injection nozzles is 2. A pressure controller is installed on an output nozzle. The outer surface of the channels with a catalyst has a roughness of 25 m.

[0045] The cobalt catalyst consisting of 44.0 wt. % Co and 56.0 wt. % ZrO.sub.2, filling the reaction channels of the compact reactor is activated by passing hydrogen with a space velocity of 5000 h.sup.1 at a temperature of 250 C. and a pressure of 1.9 MPa for 28 hours.

[0046] The Fischer-Tropsch process for the production of synthetic hydrocarbons in the compact reactor runs at an H.sub.2/CO ratio in synthesis gas of 2.37, a synthesis gas feed space velocity of 10000 h.sup.1, a temperature of 210 C. and a pressure of 2.0 MPa. In addition, every 350 hours the synthesis gas space velocity is increased up to 20000 h.sup.1 by 3 hours, followed by returning to the initial conditions of the synthesis.

[0047] The composition of synthetic hydrocarbons resulting from the Fischer-Tropsch process in a compact version in the reactor according to the invention is as follows:

[0048] 54 wt. % of C.sub.5-C.sub.10 hydrocarbons;

[0049] 39 wt. % of C.sub.11-C.sub.18 hydrocarbons; and

[0050] 7 wt. % of C.sub.19+ hydrocarbons.

[0051] Characteristics of the reactor and cobalt catalyst obtained in the method of producing synthetic hydrocarbons in the Fischer-Tropsch process in a compact version in the reactor according to the invention are given in the table below.

Example 2

[0052] The structure of a compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process includes a housing containing 50 reaction channels filled with a cobalt catalyst containing 46.0 wt. % Co, 13.5 wt. % ZrO.sub.2, and 40.5 wt. % SiO.sub.2; wherein the reaction channels has a thickness of 1 mm, a width-to-thickness ratio of 2, and a height-to-thickness ratio of 400 and are placed in an outer housing sealed with two flange connections. The thickness of the wall of the reaction channel is 1 mm. The distance between the nearest reaction channels is 1 mm. The ratio of the total cross-sectional area of the channels to the cross-sectional area of the housing is 0.89. To obtain a uniform flow distribution of feedstock, the ratio of the number of channels to the number of synthesis gas injection nozzles is 50. A pressure controller is installed on an output nozzle. The outer surface of the channels with a catalyst has a roughness of 11 m.

[0053] The catalyst consisting of 46.0 wt. % Co, 13.5 wt. % ZrO.sub.2, and 40.5 wt. % of SiO.sub.2, filling the reaction channels of the compact reactor is activated by passing hydrogen with a space velocity of 1000 h.sup.1 at a temperature of 280 C. and a pressure of 3.0 MPa for 48 hours.

[0054] The Fischer-Tropsch process for the production of synthetic hydrocarbons in the compact reactor runs at an H.sub.2/CO ratio in synthesis gas of 2.12, a synthesis gas feed space velocity of 15000 h.sup.1, a temperature of 250 C. and a pressure of 1.0 MPa. In addition, every 300 hours the synthesis gas space velocity is increased up to 30000 h.sup.1 by 5 hours, followed by returning to the initial conditions of the synthesis.

[0055] The composition of synthetic hydrocarbons resulting from the Fischer-Tropsch process in a compact version in the reactor according to the invention is as follows:

[0056] 62 wt. % of C.sub.5-C.sub.10 hydrocarbons;

[0057] 33 wt. % of C.sub.11-C.sub.18 hydrocarbons; and

[0058] 5 wt. % of C.sub.19+ hydrocarbons.

[0059] Characteristics of the reactor and cobalt catalyst obtained in the method of producing synthetic hydrocarbons in the Fischer-Tropsch process in a compact version in the reactor according to the invention are given in the table below.

Example 3

[0060] The structure of a compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process includes a housing containing eight reaction channels filled with a cobalt catalyst containing 48.0 wt. % Co, 2.0 wt. % Re, and 50.0 wt. % ZrO.sub.2; wherein the reaction channels has a thickness of 5 mm, a width-to-thickness ratio of 100, and a height-to-thickness ratio of 1000 and are placed in an outer housing sealed with two flange connections. The thickness of the wall of said reaction channel is 3 mm. The distance between the nearest reaction channels is 5 mm. The ratio of the total cross-sectional area of the channels to the cross-sectional area of the housing is 0.38. To obtain a uniform flow distribution of feedstock, the ratio of the number of channels to the number of synthesis gas injection nozzles is 1. A pressure controller is installed on an output nozzle. The outer surface of the channels with a catalyst has a roughness of 1.6 m.

[0061] The cobalt catalyst consisting of 48.0 wt. % Co, 2.0 wt. % Re, and 50.0 wt. % ZrO.sub.2, filling the reaction channels of the compact reactor is activated by passing hydrogen with a space velocity of 30000 h.sup.1 at a temperature of 200 C. and a pressure of 1.2 MPa for 12 hours.

[0062] The Fischer-Tropsch process for the production of synthetic hydrocarbons in the compact reactor runs at an H.sub.2/CO ratio in synthesis gas of 2.60, a synthesis gas feed space velocity of 19000 h.sup.1, a temperature of 260 C., and a pressure of 3.0 MPa. In addition, every 500 hours the synthesis gas space velocity is increased up to 25000 h.sup.1 by 1 hour, followed by returning to the initial conditions of the synthesis.

[0063] The composition of synthetic hydrocarbons resulting from the Fischer-Tropsch process in a compact version in the reactor according to the invention is as follows:

[0064] 64 wt. % of C.sub.5-C.sub.10 hydrocarbons;

[0065] 32 wt. % of C.sub.11-C.sub.18 hydrocarbons; and

[0066] 4 wt. % of C.sub.109+ hydrocarbons.

[0067] Characteristics of the reactor and catalyst obtained in the method of producing synthetic hydrocarbons in Fischer-Tropsch process in a compact version in the reactor according to the invention are given in the table below.

Example 4

[0068] The structure of a compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process includes a housing containing 12 reaction channels filled with a cobalt catalyst containing 50.0 wt. % Co, 0.5 wt. % Ru, 19.8 wt. % Al.sub.2O.sub.3, and 29.7 wt. % SiO.sub.2; wherein the reaction channels has a thickness of 3 mm, a width-to-thickness ratio of 5, and a height-to-thickness ratio of 20 and are placed in an outer housing sealed with two flange connections. The thickness of the wall of said reaction channel is 2 mm. The distance between the nearest reaction channels is 4 mm. The ratio of the total cross-sectional area of the channels to the cross-sectional area of the housing is 0.52. To obtain a uniform flow distribution of feedstock, the ratio of the number of channels to the number of synthesis gas injection nozzles is 4. A pressure controller is installed on an output nozzle. The outer surface of the channels with a catalyst has a roughness of 17 m.

[0069] The cobalt catalyst consisting of 50.0 wt. % Co, 0.5 wt. % Ru, 19.8 wt. % Al.sub.2O.sub.3, and 29.7 wt. % SiO.sub.2, filling the reaction channels of the compact reactor is activated by passing hydrogen with a space velocity of 30000 h.sup.1 at an H.sub.2/CO ratio in synthesis gas of 2.52, a synthesis gas feed space velocity of 13000 h.sup.1, a temperature of 240 C., and a pressure of 2.0 MPa. In addition, every 400 hours the synthesis gas space velocity is increased up to 28000 h.sup.1 by 2 hours, followed by returning to the initial conditions of the synthesis.

[0070] The composition of synthetic hydrocarbons resulting from the Fischer-Tropsch process in a compact version in the reactor according to the invention is as follows:

[0071] 60 wt. % of C.sub.5-C.sub.10 hydrocarbons;

[0072] 33 wt. % of C.sub.11-C.sub.18 hydrocarbons; and

[0073] 7 wt. % of C.sub.19+ hydrocarbons.

[0074] Characteristics of the reactor and catalyst obtained with the method of producing synthetic hydrocarbons in the Fischer-Tropsch process in a compact version in the reactor according to the invention are given in the table below.

TABLE-US-00001 TABLE Characteristics of the Fischer-Tropsch process Output per unit CO C5+ Catalyst mass of the conversion, selectivity, productivity, reactor, Example % % kg C.sub.5+/m.sup.3.sub.cat/h g C.sub.5+/kg.sub.r/day 1 70.2 70.2 1212.7 1163.5 2 70.7 66.3 1432.6 1375.3 3 69.9 61.0 1673.3 1606.8 4 69.8 68.3 1348.4 1294.7

[0075] The design of a compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process, a method for activating a Fischer-Tropsch catalyst, and a method for Fischer-Tropsch synthesis in a compact version using the compact reactor, implemented according to the present invention ensure the production of synthetic hydrocarbons in the Fischer-Tropsch process in the compact reactor at a cobalt catalyst productivity of more than 1200 kg/m.sup.3.sub.cat.Math.h and daily output per unit mass of the reactor of more than 1160 g C.sub.5+/kg.sub.r/day, suggesting that the claimed group of inventions is useful for the Fischer-Tropsch process in the compact reactor directly at the fields for highly effective utilization of APG and natural gas.

[0076] The design of a compact reactor for the production of synthetic hydrocarbons in a Fischer-Tropsch process, a method for activating a cobalt Fischer-Tropsch catalyst, and the method for the Fischer-Tropsch synthesis in a compact version using the compact reactor, according to the invention, are more efficient than those known in the art.