1. A catalyst comprising at least one modified EU-1 zeolite containing silicon atoms and aluminium atoms, at least one matrix and at least one metal from group VIM of the periodic table of the elements, said catalyst being characterized in that the number of hexacoordinated aluminium atoms present in said modified zeolite represents more than 20% by weight of the total number of aluminium atoms present in said modified EU-1 zeolite.
2. A catalyst according to claim 1, in which said modified EU-1 zeolite has a number of hexacoordinated aluminium atoms representing more than 22% by weight of the total number of aluminium atoms present in said modified zeolite.
3. A catalyst according to claim 1, in which said modified EU-1 zeolite has a number of hexacoordinated aluminium atoms representing more than 25% by weight of the total number of aluminium atoms present in said modified zeolite.
4. A catalyst according to claim 1, in which said modified EU-1 zeolite has a number of hexacoordinated aluminium atoms representing more than 30% by weight of the total number of aluminium atoms present in said modified zeolite.
5. A catalyst according to claim 1, in which said modified EU-1 zeolite has an overall SiAl atomic ratio in the range 10 to 35.
6. A catalyst according to claim 1, in which said group VIII metal is platinum.
7. A catalyst according to claim 1, comprising at least one additional metal selected from the group formed by metals from groups IIIA, IVA and VIIB.
8. A catalyst according to claim 1, comprising sulphur.
9. A catalyst according to claim 1, in which said matrix is an alumina.
10. A catalyst according to claim 1, in which it is in the form of extrudates.
11. A process for preparing a catalyst according to claim 1, comprising at least the following steps:
a1) synthesizing at least one EU-1 zeolite having an overall SiAl atomic ratio in the range 5 to 100;
b1) heat treating the zeolite from said step a1) in the presence of steam to obtain a modified EU-1 zeolite;
c1) forming said modified EU-1 zeolite with a matrix to form a modified zeolitic support;
d1) depositing at least one metal from group VIII of the periodic table of the elements, the order of carrying out said steps c1) and d1) being inconsequential following upon said step b1).
12. A preparation process according to claim 11, in which said heat treatment in the presence of steam is carried out at a temperature in the range 200\xb0 C. to 470\xb0 C., for a period in the range 0.5 hours to 24 hours, the percentage by volume of steam being in the range 5% to 100%.
13. A preparation process according to claim 11, in which said step c1) precedes said step d1).
14. A process for preparing a catalyst according to claim 1, comprising at least the following steps:
a2) synthesizing at least one EU-1 zeolite having an overall SiAl atomic ratio in the range 5 to 100;
b2) forming the EU-1 zeolite from said step a2) with a matrix to form a zeolitic support;
c2) heat treating the zeolitic support formed in step b2) in the presence of steam;
d2) depositing at least one metal from group VIII of the periodic table of the elements on the modified zeolitic support of step c2).
15. A process for preparing a catalyst according to claim 1, comprising at least the following steps:
a3) synthesizing at least one EU-1 zeolite having an overall SiAl atomic ratio in the range 5 to 100;
b3) forming the EU-1 zeolite from said step a3) with a matrix to form a zeolitic support;
c3) depositing at least one metal from group VIII of the periodic table of the elements on the zeolitic support from said step b3);
d3) heat treating the zeolitic support impregnated with at least said group VIII metal from said step c3) in the presence of steam.
16. A process for isomerizing a cut containing at least one aromatic compound containing eight carbon atoms per molecule, said process comprising bringing said aromatic cut into contact with at least one catalyst comprising a modified zeolite according to claim 1, present in a catalytic reactor.
17. An isomerization process according to claim 16, carried out under the following operating conditions: a temperature in the range 300\xb0 C. to 500\xb0 C., a partial pressure of hydrogen in the range 0.3 to 1.5 MPa, a total pressure in the range 0.45 to 1.9 MPa and a space velocity, expressed in kilograms of feed introduced per kilogram of catalyst per hour, in the range 0.25 to 30 h\u22121.
18. An isomerization process according to claim 16, in which the EU-1 zeolite present in said catalyst has been modified by a heat treatment in the presence of steam, said treatment being carried out in situ and prior to bringing said catalyst into contact with said aromatic cut.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for cooling a stand-alone computing device separate from a server rack, the stand-alone computing device comprising a substantially vertical first face having an inlet portion comprising no more than about a lower 33% of a height of the first face for inlet gas flow and a substantially vertical second face opposite the first face for outlet gas flow, the method comprising:
providing a cooling host module for providing cooling gas flow in a substantially isolated closed loop through the stand-alone computing device, the cooling host module including a vertical portion and a horizontal portion, the stand-alone computing device supported by the horizontal portion of the cooling host module;
drawing outlet gas flow exiting through the second face of the stand-alone computing device into the vertical portion of the cooling host module, the outlet gas flow flowing through a heat exchanger disposed in the vertical portion of the cooling host module adjacent to the second face of the stand-alone computing device for cooling the gas;
providing a gas flow path in the in the vertical portion and the horizontal portion of the cooling host module for directing air exiting the heat exchanger into the horizontal portion of the cooling host module beneath the computing device;
moving gas in the gas flow path through the vertical portion of the cooling host module, through the horizontal portion of the cooling host module, and into and through an interior of the stand-alone computing device by a gas moving device, wherein negative pressure is maintained in the vertical portion of the cooling host module to draw the outlet gas flow exiting the stand-alone computing device into the vertical portion of the cooling host module;
providing a sealing system at an interface between the second face of the stand-alone computing device and the vertical portion of the cooling host module peripheral to the outlet gas flow, the sealing system ensuring that substantially all the outlet gas flow from the stand-alone computing device enters the cooling host module; and
venting gas flow from a vent in a distal end of the horizontal portion of the cooling host module into the inlet portion of the first face of the stand-alone computing device to cool an interior of the stand-alone computing device, wherein the vent comprises an adjustably sized opening that adjusts the gas flow directed towards and into the inlet portion of the first face of the stand-alone computing device.
2. The method for cooling a stand-alone computing device as claimed in claim 1, wherein the gas moving device comprises a fan.
3. The method for cooling a stand-alone computing device as claimed in claim 1, wherein the gas comprises ambient air.
4. The method for cooling a stand-alone computing device as claimed in claim 1, wherein the vent comprises an opening shaped to direct gas flow towards and into the inlet portion of the first face of the stand-alone computing device.
5. The method for cooling a computing device as claimed in claim 1, wherein stand-alone the computing device comprises one of a mainframe computer, a mid-range computer, and a mini computer.