Method for preparing solids from a mixture of at least one malachite powder and an oxide powder and the use of said solids

Abstract

The invention relates to a method for preparing a solid comprising the mixture of a set of compounds comprising at least one Cu.sub.2(OH).sub.2CO.sub.3 powder, one metal oxide powder selected from the group of metals consisting of copper, zinc, iron, manganese and mixtures thereof, and at least one binder as well as the use of the solid prepared by means of this method.

Claims

1. A method for preparing a solid, comprising the steps of: a) mixing of a set of compounds comprising at least one malachite Cu.sub.2(OH).sub.2CO.sub.3 powder, at least one metal oxide powder selected from the group consisting of copper, zinc, iron, manganese and mixtures thereof, and at least one binder, thereby forming a mixture; b) contacting the mixture of step a) with an aqueous solution to obtain a paste and kneading the paste; c) extruding the paste kneaded in step b) at a pressure of between 3 and 25 MPa thereby obtaining extrudates; and d) calcinating the extrudates at a temperature between 140° C. and 500° C. and for a duration between 10 minutes and 6 hours under a gaseous flow comprising oxygen; wherein when the at least one metal oxide powder included in said set of compounds of said step a) is copper oxide, said set of compounds is free from zinc oxide, wherein the solid exhibits an EGG (grain by grain crushing test) value greater than 0.7 daN.Math.mm.sup.−1 and a sulfur capture capacity greater than 0.16 grams of sulfur/gram of solid, wherein the EGG value described by American Society for Testing and Materials (ASTM) D 6175-3 method, and wherein the sulfur capture capacity is determined by a test carried out at a temperature of 50° C., at a pressure of 0.3 MPa, and with an hourly volume velocity of 1530 h.sup.−1, a gas used for the test contains 0.9 vol % H.sub.2S in nitrogen, and a content of H.sub.2S present in an outlet gas from a reactor by gas chromatography.

2. The method for preparing a solid according to claim 1, wherein the extrudates obtained from step c) are dried at a temperature between 70 and 160° C. for a duration between 1 and 24 hours before being calcinated in step d).

3. The method for preparing a solid according to claim 1, wherein a content of said at least one metal oxide powder expressed as a ratio of a mass of said at least one metal oxide powder introduced into the set of compounds mixed in step a) to a total mass of the at least one malachite Cu.sub.2(OH).sub.2CO.sub.3 powder and said at least one metal oxide powder introduced into the set of compounds mixed in step a) is between 0.01 and 1.

4. The method for preparing a solid according to claim 1, wherein said at least one malachite Cu.sub.2(OH).sub.2CO.sub.3 powder has a bimodal distribution.

5. The method for preparing a solid according to claim 4, wherein said at least one malachite Cu.sub.2(OH).sub.2CO.sub.3 powder comprises 0.1 to 99.9 wt % of malachite particles with a D.sub.50 between 1 and 15 μm, and 99.9 to 0.1 wt % of malachite particles with a D.sub.50 between 25 and 100 μm, the weight percentage being expressed relative to a total weight of said at least one malachite Cu.sub.2(OH).sub.2CO.sub.3 powder.

6. The method for preparing a solid according to claim 1, wherein the solid exhibits the EGG value between 0.9 and 1.8 daN.Math.mm.sup.−1 and the sulfur capture capacity between 0.19 and 0.27 grams of sulfur/gram of solid.

7. The method for preparing a solid according to claim 1, wherein said aqueous solution of step b) contains an acid or base peptizing agent.

8. The method for preparing a solid according to claim 7, wherein said aqueous solution contains nitric acid, with a ratio of mass of HNO.sub.3 mass to mass of said at least one metallic oxide powder is between 0.5 and 10.

9. The method for preparing a solid according to claim 7, wherein said basic peptizing agent is selected from the group consisting of sodium hydroxide, potassium hydroxide, aqueous ammonia, tetraethylammonium hydroxide, ammonium carbonate and mixtures thereof, and a ratio of the basic peptizing agent to mass of said at least one metal oxide powder is between 1 and 10.

10. The method for preparing a solid according to claim 1, wherein the aqueous solution of step b) is deionized water.

11. The method for preparing a solid according to claim 1, wherein step d) of calcination is carried out at a temperature between 200° C. and 500° C.

12. The method for preparing a solid according to claim 1, wherein the at least one binder is a bentonite clay.

13. The method for preparing a solid according to claim 1, wherein the prepared solid has a content of the at least one binder between 15 wt % and 25 wt % of the solid.

14. The method for preparing a solid according to claim 1, wherein the at least one binder is a kaolinite mineral, a palygorskite mineral, a smectite clay mineral, alumina, a precursor of alumina, silica or a mixture thereof.

15. The method for preparing a solid according to claim 1, wherein said at least one metal oxide powder included in the set of compounds of the said step a) is zinc oxide, and said set of compounds being free of copper oxide.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a schematic representation of a breakthrough curve which can be obtained according to the protocol for measuring the impurity capture capacity by the solids, described below. In FIG. 1, t.sub.p is the breakthrough time and t.sub.f is the end of the breakthrough time.

(2) Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

(3) In the foregoing and in the examples, all temperatures are set forth uncorrected in degrees Celsius and, all parts and percentages are by weight, unless otherwise indicated.

(4) The entire disclosures of all applications, patents and publications, cited herein and of corresponding application No. FR 1755302, filed Jun. 13, 2017 are incorporated by reference herein.

EXAMPLES

(5) Protocol for Measuring the Impurity Capture Capacity by the Solids Prepared

(6) The impurity capture capacity of solids prepared by means of the method according to the invention is measured using a breakthrough test.

(7) For the test to determine the H.sub.2S capture capacity, the test is carried out at a temperature of 50° C., at a pressure of 0.3 MPa, and with an hourly volume velocity (HVV) of 1530 h.sup.−1. Hourly volume velocity can be understood as the ratio of the volumetric flow rate of gas measured at 0° C. and 1 atm to the volume of the solid tested. The gas used for the test contains 0.9 vol % H.sub.2S in nitrogen. The H.sub.2S content present in the outlet gas from the reactor containing the solid is determined by gas chromatography.

(8) For the test to determine the methyl mercaptan CH.sub.3SH capture capacity, the test is carried out at a temperature of 50° C., at a pressure of 0.3 MPa, and with an hourly volume velocity (HVV) of 1530 h.sup.−1. Hourly volume velocity can be understood as the ratio of the volumetric flow rate of gas measured at 0° C. and 1 atm to the volume of the solid tested. The gas used for the test contains 0.2 vol % CH.sub.3SH in nitrogen. The CH.sub.3SH content present in the outlet gas from the reactor containing the solid is determined by gas chromatography.

(9) For the test to determine the ethyl mercaptan C.sub.2H.sub.5SH capture capacity, the test is carried out at a temperature of 50° C., at a pressure of 0.3 MPa, and with an hourly volume velocity (HVV) of 1530 h.sup.−1. Hourly volume velocity can be understood as the ratio of the volumetric flow rate of gas measured at 0° C. and 1 atm to the volume of the solid tested. The gas used for the test contains 0.9 vol % C.sub.2H.sub.5SH in nitrogen. The C.sub.2H.sub.5SH content present in the outlet gas from the reactor containing the solid is determined by gas chromatography.

(10) For the test to determine the carbon monoxide CO capture capacity, the test is carried out at a temperature of 200° C., at a pressure of 0.1 MPa, and with an hourly volume velocity (HVV) of 2600 h.sup.−1. Hourly volume velocity can be understood as the ratio of the volumetric flow rate of gas measured at 0° C. and 1 atm to the volume of the solid tested. The gas used for the test contains 1.8 vol % CO. The CO content present in the outlet gas from the reactor containing the solid is determined by gas chromatography.

(11) The species i capture capacity by the solid prepared by means of the method according to the invention is determined by carrying out a material balance. The species i capture capacity, as defined within the present invention, corresponds to the amount of the species i accumulated by the solid before breakthrough (i.e. at the time t.sub.p indicated in FIG. 1, which schematically represents a breakthrough curve), this being calculated by means of the following equation:

(12) $q_i=M_i{D}_i^E{\int }_0^{t_p}\left(1-\frac{C_i^S}{C_i^E}\right)\mathrm{dt}$
Where:
q.sub.i: is the mass of the species i captured by the solid (in g),
D.sub.i.sup.E: is the inflow of the species i (in mol.Math.min.sup.−1),
M.sub.i: is the molar mass of the species i (in g.Math.mol.sup.−1),
C.sub.i.sup.E: is the species i content of the inflow gas,
C.sub.i.sup.S: is the species i content at the reactor outlet,
t.sub.p: is the time needed for the breakthrough of the species i (in minutes) as shown in FIG. 1.

(13) In FIG. 1, t.sub.p is the breakthrough time and t.sub.f is the end of the breakthrough time.

(14) The species i capture capacity of the solid tested is provided by the equation:

(15) $C_i=\frac{q_i}{m}$
where m is the mass of adsorbent implemented during the test.

Example 1: According to the Prior Art

(16) In example 1, the reference solids A1, A2, A3, A4 and A5 are prepared according to the following working method: a) mixing a set of compounds comprising a Cu.sub.2(OH).sub.2CO.sub.3 powder and a binder; b) contacting the mixture of step a) with an aqueous solution (peptization) and kneading the paste thus obtained in a Z-arm mixer for 30 minutes with an arm rotation speed of 25 rotations.Math.minutes.sup.−1; c) extruding the paste kneaded in step b) by means of a piston extruder, with a diameter of 3 mm and a length of 5 to 10 mm at a variable pressure depending on the solids; d) calcinating the extrudates at a variable temperature depending on the solids, carried out for 1 hour, under an air flow.

(17) A bentonite clay was used as a binder.

(18) The CuO contents or mass percentage of oxides (CuO from the decomposition of malachite) after loss on ignition (550° C. for 2 hours) are 80 wt % for solids A1, A2, A3 and A4, and 60 wt % for solid A5 (with bentonite binder as the complement). These contents are determined according to the following:

(19) $\%\mathrm{weight}\mathrm{CuO}\mathrm{after}\mathrm{LOI}=\frac{\frac{2.Math.M_{\mathrm{CuO}}}{M_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}.Math.m_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}{m_{\mathrm{binder}}+\frac{2.Math.M_{\mathrm{CuO}}}{M_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}.Math.m_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}$
Where m.sub.binder is the mass of the binder introduced in step a), M.sub.Cu2(OH)2CO3 is the mass of the Cu.sub.2(OH).sub.2CO.sub.3 malachite introduced in step a), M.sub.CuO is the molar mass of CuO (=80 g/mol), M.sub.Cu2(OH)2CO3 is the molar mass of Cu.sub.2(OH).sub.2CO.sub.3 malachite (=222 g/mol).

(20) For solids A1, A2 and A3, the amount of NaOH base is 4% by weight relatively to the total amount of Cu.sub.2(OH).sub.2CO.sub.3 introduced.

(21) For solids A4 and A5, deionised water is used as the aqueous solution for step b) of kneading. During the extrusion, the pressure varies between 50 and 150 bar depending on the formulation used.

(22) The formulations of solids A1, A2, A3, A4 and A5 are given in Table 1.

(23) TABLE-US-00001 TABLE 1 Test for CuO/(CuO + capturing Cu.sub.2(OH).sub.2CO.sub.3) % Calcination H.sub.2S: Sulphur ratio, oxides temperature captured at introduced in after (° C.)/ tp (g S/g EGG Designation step a) LOI Binder Peptisation duration (h) solid) (daN .Math. mm.sup.−1) Solid A1 0 80% Bentonite 4% NaOH 140° C./1 h 0.22 0.5 Solid A2 0 80% Bentonite 4% NaOH 250° C./1 h 0.25 0.5 Solid A3 0 80% Bentonite 4% NaOH 350° C./1 h 0.24 0.5 Solid A4 0 80% Bentonite water 250° C./1 h 0.26 0.3 Solid A5 0 60% Bentonite water 250° C./1 h 0.16 0.6

(24) The mechanical strength of the extrudates is determined by a grain by grain crushing test (EGG) as previously described.

(25) The mechanical strength of solids A1 to A5 is too low taking into consideration the constraints associated with an industrial use. The EGG values measured are lower than 0.7 daN.Math.mm.sup.−1, whatever the calcination temperature and the presence or lack of sodium hydroxide during peptization.

(26) The increase in binder content and the decrease in malachite content in solid A5 results in a slight increase in mechanical strength which is nevertheless insufficient, to the detriment of the sulphur capture capacity thereof. In this latter case, the sulphur capacity becomes weak compared to that of the solids according to the invention.

Example 2: According to the Invention

(27) In example 2, the solids referenced as B1 to B4 according to the invention are prepared by kneading and extruding according to the following procedure: a) mixing a set of compounds comprising a Cu.sub.2(OH).sub.2CO.sub.3 powder, a CuO powder, and a binder; b) contacting the mixture of step a) with an aqueous solution (peptization) and kneading the paste thus obtained in a Z-arm mixer for 30 minutes with an arm rotation speed of 25 rotations.Math.minutes.sup.−1; c) extruding the paste kneaded in step b) by means of a piston extruder, with a diameter of 3 mm and a length of 5 to 10 mm at a variable pressure depending on the solids; d) calcinating the extrudates at a variable temperature depending on the examples, carried out for 1 hour, under air flow.

(28) A bentonite clay was used as a binder.

(29) The CuO content or mass percentage of oxides (oxide+CuO content, CuO from the decomposition of malachite) after loss on ignition (550° C. for 2 hours) is 80 wt % for solids B1 to B4. This content is determined according to the following equation:

(30) $\%\mathrm{weight}\mathrm{CuO}\mathrm{after}\mathrm{LOI}=\frac{m_{\mathrm{CuO}}+\frac{2.Math.M_{\mathrm{CuO}}}{M_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}.Math.m_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}{m_{\mathrm{binder}}+m_{\mathrm{CuO}}+\frac{2.Math.M_{\mathrm{CuO}}}{M_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}.Math.m_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}$

(31) Where m.sub.CuO is the mass of CuO initially introduced in step a) in the form of CuO powder, m.sub.binder is the mass of the binder introduced in step a), M.sub.Cu2(OH)2CO3 is the malachite Cu.sub.2(OH).sub.2CO.sub.3 mass introduced in step a), M.sub.CuO is the molar mass of CuO (=80 g/mol), M.sub.Cu2(OH)2CO3 is the molar mass of malachite Cu.sub.2(OH).sub.2CO.sub.3 (=222 g/mol).

(32) For solid B1, the amount of NaOH base is 4 wt % relatively to the total amounts of Cu.sub.2(OH).sub.2CO.sub.3 and CuO introduced.

(33) For solids B2, B3 and B4, deionised water is used as the aqueous solution for step b) of kneading. During the extrusion, the pressure varies between 50 and 200 bar depending on the formulation used.

(34) The formulations of the solids are given in Table 2.

(35) TABLE-US-00002 TABLE 2 Test for CuO/(CuO + capturing Cu.sub.2(OH).sub.2CO.sub.3) % Calcination H.sub.2S: Sulphur ratio, oxydes temperature captured at introduced in after (° C.)/ tp (g S/g EGG Designation step a) LOI Binder Peptization duration (h) solid) (daN .Math. mm.sup.−1) Solid B1 0.5 80% Bentonite 4% NaOH 350° C./1 h 0.2 1.8 Solid B2 0.5 80% Bentonite water 350° C./1 h 0.23 1.4 Solid B3 0.5 80% Bentonite water 250° C./1 h 0.22 1.2 Solid B4 0.2 80% Bentonite water 350° C./1 h 0.27 1.0

(36) The combined use of CuO and Cu.sub.2(OH).sub.2CO.sub.3 in the preparation method according to the invention makes it possible to obtain solids having satisfactory mechanical properties (EGG greater than 0.7 daN.Math.mm.sup.−1). Furthermore, the solids have satisfactory sulphurisation capacities, greater than 0.15 grams of sulphur/gram of solid in the test conditions described in the document.

Example 3: According to the Invention

(37) In example 3, the solids referenced as C1 and C2 according to the invention are prepared by kneading and extruding according to the following procedure: a) mixing a set of compounds comprising a Cu.sub.2(OH).sub.2CO.sub.3 powder, a ZnO powder, and a binder; b) contacting the mixture of step a) with an aqueous solution (peptization) and kneading the paste thus obtained in a Z-arm mixer for 30 minutes with an arm rotation speed of 25 rotations.Math.minutes.sup.−1; c) extruding the paste kneaded in step b) by means of a piston extruder, with a diameter of 3 mm and a length of 5 to 10 mm at a variable pressure depending on the solids; d) calcinating the extrudates at a variable temperature depending on the examples, carried out for 1 hour, under air flow.

(38) A bentonite clay was used as a binder.

(39) The CuO+ZnO content or mass percentage of oxides (oxide+CuO content, CuO from the decomposition of malachite) after loss on ignition (550° C. for 2 hours) is 80 wt % for solids C1 and C2. This contest is determined according to the following:

(40) $\%\mathrm{weight}\mathrm{oxides}\mathrm{after}\mathrm{LOI}=\frac{m_{\mathrm{ZnO}}+\frac{2.Math.M_{\mathrm{CuO}}}{M_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}.Math.m_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}{m_{\mathrm{binder}}+m_{\mathrm{ZnO}}+\frac{2.Math.M_{\mathrm{CuO}}}{M_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}.Math.m_{{{\mathrm{Cu}}_2\left(\mathrm{OH}\right)}_2{\mathrm{CO}}_3}}$

(41) Where m.sub.ZnO is the mass of ZnO initially introduced in step a) in the form of ZnO powder, m.sub.binder is the mass of the binder introduced in step a), M.sub.Cu2(OH)2CO3 is the malachite Cu.sub.2(OH).sub.2CO.sub.3 mass introduced in step a), M.sub.CuO is the molar mass of CuO (=80 g/mol), M.sub.Cu2(OH)2CO3 is the molar mass of malachite Cu.sub.2(OH).sub.2CO.sub.3 (=222 g/mol).

(42) For solids C1 and C2, the amount of NaOH base is 4 wt % relatively to the total amounts of Cu.sub.2(OH).sub.2CO.sub.3 and CuO introduced.

(43) During the extrusion, the pressure varies between 50 and 150 bar depending on the formulation used.

(44) The formulations of the solids are given in Table 3.

(45) TABLE-US-00003 TABLE 3 Test for ZnO/(ZnO + capturing Cu.sub.2(OH).sub.2CO.sub.3) % Calcination H.sub.2S: Sulphur ratio, oxydes temperature captured at introduced in after (° C.)/ tp (g S/g EGG Designation step a) LOI Binder Peptization duration (h) solid) (daN .Math. mm.sup.−1) Solid C1 0.2 80% Bentonite 4% NaOH 200° C./1 h 0.19 1.0 Solid C2 0.2 80% Bentonite 4% NaOH 350° C./1 h 0.19 0.9

(46) The combined use of ZnO and Cu.sub.2(OH).sub.2CO.sub.3 in the preparation method according to the invention makes it possible to obtain solids having satisfactory mechanical properties (EGG greater than 0.7 daN.Math.mm.sup.−1). Furthermore, the solids have satisfactory sulphurisation capacities, greater than 0.15 grams of sulphur/gram of solid in the test conditions described in the document.

Example 4: According to the Invention

(47) Example 4 shows the capture performances of solid B3 according to the invention, the preparation of which is described in example 2.

(48) The performances of capturing diverse impurities have been determined according to the protocol for measuring the impurity capture capacity by the prepared solids, described above.

(49) The capacities of capture of the following sulphur compounds H.sub.2S, CH.sub.3SH, C.sub.2H.sub.5SH, as well as the capture of carbon monoxide CO have been evaluated in the test conditions described in the protocol.

(50) The results of the tests are presented in Table 4.

(51) TABLE-US-00004 TABLE 4 Test for capturing Test for capturing Test for capturing Test for capturing H.sub.2S: Sulphur CH.sub.3SH: Sulphur C.sub.2H.sub.5SH: Sulphur CO: mass of CP captured at tp (g captured at tp (g captured at tp (g captured at tp (g EGG Tested solid S/g solid) S/g solid) S/g solid) CO/g solid (daN .Math. mm.sup.−1) Solid B3 0.22 0.06 0.19 0.23 1.2

(52) The results show that the solid B3 obtained from the method according to the invention makes it possible to remove the sulphur compounds H.sub.2S, CH.sub.3SH, C.sub.2H.sub.5SH contained in the gas, by sequestering sulphur on solid B3 before breakthrough (before t.sub.p) in line with the capacities given in Table 4, in test conditions.

(53) Solid B3 is also able to purify a gas containing carbon monoxide by capturing, in the measurement conditions, 0.23 grams of CO per gram of solid before starting to observe the appearance of carbon monoxide at the reactor outlet (i.e. before the breakthrough t.sub.p).

(54) The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

(55) From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.