1. A process for the removal of sulfur compounds from a hydrocarbon stream, especially a gaseous hydrocarbon gas stream, comprising said sulfur compounds, which process comprises contacting said gas stream with an adsorbent comprising a zeolite having a pore diameter of at least 5 \u212b to adsorb the sulfur compounds thereon, the adsorption process followed by a regeneration process in the presence of water of used, loaded adsorbent, by contacting the said loaded adsorbent with a regeneration gas stream having a relative humidity of at most 30%, wherein the regeneration gas is an inert gas or an inert gas mixture.
2. A process according to claim 1, in which the hydrocarbon stream is natural gas, associated gas, a natural gas liquids stream, a natural gas condensate stream or a refinery gas stream.
3. A process according to claim 2, in which the sulfur compounds are hydrogen sulfide, carbonyl sulfides, mercaptans, especially C1-C6 mercaptans, organic sulfides, especially di-C1-C4-alkyl sulphides, organic sulfides, especially di-C1-C4-alkyl disulfides, thiophene compounds, aromatic mercaptans, especially phenyl mercaptan, or mixtures thereof, more especially C1-C4 mercaptans, and the total amount of sulfur compounds contained in the hydrocarbon stream is up to 3 vol % based on total gas stream.
4. A process according to claim 3, in which the gas stream also comprises water, which is removed by adsorbing the water on a zeolite having a pore diameter of less than 5 \u212b.
5. A process according to claim 4, in which the gas stream also comprises hydrogen sulfide and optionally carbon dioxide and, up to 2 vol % hydrogen sulfide, with the hydrogen sulfide and part of the carbon dioxide preferably being removed by means of washing the gas stream with a chemical solvent.
6. A process according to claim 5, in which the temperature of the zeolite adsorption process is between 10 and 60\xb0 C., the pressure is between 10 and 150 bara, and the superficial gas velocity is between 0.03 and 0.6 ms.
7. A process for the regeneration of an adsorbent comprising a zeolite having a pore diameter of at least 5 \u212b and loaded with sulfur compounds by contacting the adsorbent with a regeneration gas stream having a relative water humidity less than 100.
8. A process according to claim 7, in which the adsorbent comprises zeolite dispersed in a binder.
9. A process according to claim 8, in which the adsorbent is in the form of at least two beds, one bed comprising zeolite having a pore diameter of 5 \u212b, the second and, if present, further beds comprising a zeolite having a pore diameter of more than 5 \u212b.
10. A process according to claim 9, in which the regeneration is carried out at a pressure between 1 and 150 bara, a temperature between 200 and 400\xb0 C., and a superficial gas velocity of less than 0.20 ms, the regeneration gas stream.
11. A process according to claim 10, in which the regeneration gas stream is a gas stream obtained by saturating the stream at a temperature below the regeneration temperature.
12. A process according to claim 11, in which the regeneration gas stream has a relative humidity between 0.1 and 30%.
13. A process for reducing the degradation of a sulfur loaded adsorbent, wherein the sulfur loaded adsorbent is regenerated in the presence of water by contacting the said loaded adsorbent with a regeneration gas stream having a relative humidity of at most 100%, wherein the regeneration gas is an inert gas or an inert gas mixture.
14. A process for the removal of sulfur compounds from a hydrocarbon stream, wherein said hydrocarbon stream contains a sulfur compound selected from the group consisting of hydrogen sulfide, carbonyl sulfide, mercaptans, organic sulfides, organic disulfides, thiophene compounds, aromatic mercaptans and mixtures thereof, said process comprises:
contacting said hydrocarbon stream with an adsorbent comprising a zeolite having a pore diameter of at least 5 \u212b to absorb said sulfur compound thereon to thereby provide a sulfur loaded adsorbent; and contacting said sulfur loaded adsorbent with a regeneration gas stream having a relative humidity of at most 30%, wherein the regeneration gas comprises an inert gas.
15. A process according to claim 14, wherein said hydrocarbon stream is selected from the group consisting of natural gas, associated gas, a natural gas liquid, natural gas condensate or refinery gas.
16. A process according to claim 15, wherein said mercaptans include C1-C6 mercaptans, said organic sulfides include di-C1-C4-alkyl sulfides, organic disulfides include di-C1-C4-alkyl disulfides, said aromatic mercaptans include phenyl mercaptan, and the total amount of said sulfur compounds contained in said hydrocarbon sstream is up to 3 vol % based on total gas stream.
17. A process according to claim 16, wherein said hydrocarbon stream is treated to remove water therefrom prior to contacting said hydrocarbon stream with said adsorbent contacting said hydrocarbon stream with a zeolite having a pore diameter of less than 5 \u212b.
18. A process according to claim 17, in which said hydrocarbon stream prior to contacting with said adsorbent, comprises hydrogen sulfide in the range up to 2 vol % hydrogen sulfide, and a part thereof is removed by means of washing with a chemical solvent.
19. A process according to claim 18, in which the temperature of the step of contacting said hydrocarbon stream with said adsorbent is between 10 and 60\xb0 C., the pressure is between 10 and 150 bara, and the superficial gas velocity is between 0.03 and 0.6 ms.
20. A process for the regeneration of adsorbent comprising a zeolite having a pore diameter of at least 5 \u212b and which is loaded with a sulfur compound by contacting the adsorbent with a regeneration gas stream having a relative water humidity of at least 0.1% and less than 100%.
21. A process according to claim 20, in which said adsorbent further comprises said zeolite dispersed in a binder.
22. A process according to claim 21, in which said adsorbent is contained in at least two beds, with one bed comprising zeolite having a pore diameter of 5 \u212b, and with a second bed comprising a zeolite having a pore diameter of more than 5 \u212b.
23. A process according to claim 22, in which the contacting step is carried out at a pressure between 1 and 150 bara, a temperature between 200 and 400\xb0 C. and a superficial gas velocity of less than 0.20 ms.
24. A process according to claim 23, in which said regeneration gas stream is a gas stream obtained by saturating the stream at a temperature below the regeneration temperature.
25. A process according to claim 24, in which said regeneration gas stream has a relative humidity between 0.1 and 30%.
The claims below are in addition to those above.
All refrences to claims which appear below refer to the numbering after this setence.
1. An implantable medical device, comprising:
a first sensor for sensing a first signal in a patient correlated to a first physiological condition;
a second sensor for sensing a second signal in the patient corresponding to a second physiological condition;
a third sensor for sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition; and
control circuitry for receiving the first, second and third signals and being configured to determine a relationship between the second signal and the third signal, detect a change in the relationship between the second signal and the third signal, determine a threshold in response to detecting the change in the relationship between the second signal and the third signal, and detect an event in response to the first signal crossing the determined threshold.
2. An implantable medical device according to claim 1 further comprising alarm circuitry for generating an alarm in response to detection of the event.
3. An implantable medical device according to claim 1 wherein the first sensor signal being correlated to thoracic fluid level.
4. An implantable medical device according to claim 3 wherein the first sensor signal being an impedance signal.
5. An implantable medical device according to claim 1 wherein the second sensor signal being correlated to patient activity and wherein the third sensor signal being correlated to respiration rate.
6. An implantable medical device according to claim 5 wherein determining the relationship between the second signal and the third signal includes measuring the third signal in response to the second signal corresponding to a first activity level and measuring the third signal in response to the second signal corresponding to a second activity level.
7. An implantable medical device according to claim 1 wherein detecting a change in the relationship between the second signal and the third signal includes sensing the second signal and the third signal in response to a change in the first signal.
8. An implantable medical device according to claim 7 wherein the change in the first signal corresponding to an increase in thoracic fluid level.
9. An implantable medical device according to claim 1, wherein:
the first sensor signal being correlated to a thoracic fluid level, the second sensor signal being correlated to patient activity, and the third sensor signal being correlated to respiration rate, and
wherein detecting a change in the relationship between the second and third signals includes determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to activity level compared to a previously measured respiration rate response, and
wherein setting the threshold includes determining a first sensor signal level corresponding to the increase in the respiration rate response.
10. A method for use in an implantable medical device, comprising:
sensing a first signal in a patient correlated to a first physiological condition;
sensing a second signal in the patient corresponding to a second physiological condition;
sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition;
determining a relationship between the second signal and the third signal, detecting a change in the relationship between the second signal and the third signal,
determining a threshold in response to the detected change in the relationship between the second signal and the third signal, and
detecting an event in response to the first signal crossing the determined threshold.
11. A method according to claim 10, further comprising generating an alarm in response to detection of the event.
12. A method according to claim 10, wherein the first signal being correlated to thoracic fluid level.
13. A method according to claim 12, wherein the first signal being an impedance signal.
14. A method according to claim 10 wherein the second sensor signal being correlated to patient activity and wherein the third sensor signal being correlated to respiration rate.
15. A method according to claim 14 wherein determining the relationship between the second signal and the third signal includes measuring the third signal in response to the second signal corresponding to a first activity level and measuring the third signal in response to the second signal corresponding to a second activity level.
16. A method according to claim 10, wherein detecting a change in the relationship between the second signal and the third signal includes sensing the second signal and the third signal in response to a change in the first signal.
17. A method according to claim 16, wherein the change in the first signal corresponding to an increase in thoracic fluid level.
18. A method according to claim 10 wherein:
the first signal being correlated to a thoracic fluid level, the second signal being correlated to patient activity, and the third signal being correlated to respiration rate, and
wherein detecting a change in the relationship between the second and third signals includes determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to the activity level compared to a previously measured respiration rate response, and
wherein setting the threshold includes determining a first sensor signal level corresponding to the increase in the respiration rate response.
19. A computer-readable medium for storing a set of instructions which when implemented in an implantable medical device system including a microprocessor cause the system to:
sense a first signal in a patient correlated to a first physiological condition;
sense a second signal in the patient corresponding to a second physiological condition;
sense a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition;
determine a relationship between the second signal and the third signal,
detect a change in the relationship between the second signal and the third signal,
determine a threshold in response to the detected change in the relationship between the second signal and the third signal, and
detect an event in response to the first signal crossing the determined threshold.
20. A computer-readable medium according to claim 19, further comprising instructions which cause the system to generate an alarm in response to detection of the event.
21. A computer-readable medium according to claim 19, wherein the first signal being correlated to thoracic fluid level.
22. A computer-readable medium according to claim 21, wherein the first signal being an impedance signal.
23. A computer-readable medium according to claim 19, wherein the second signal being correlated to patient activity and wherein the third signal being correlated to respiration rate.
24. A computer-readable medium according to claim 23, wherein instructions for determining the relationship between the second signal and the third signal include instructions for measuring the third signal in response to the second signal corresponding to a first activity level and measuring the third signal in response to the second signal corresponding to a second activity level.
25. A computer-readable medium according to claim 19, wherein instructions for detecting a change in the relationship between the second signal and the third signal include instructions for sensing the second signal and the third signal in response to a change in the first signal.
26. A computer-readable medium according to claim 25, wherein the change in the first signal corresponding to an increase in thoracic fluid level.
27. A computer-readable medium according to claim 19, wherein:
the first signal being correlated to a thoracic fluid level, the second signal being correlated to patient activity, and the third signal being correlated to respiration rate, and
wherein instructions for detecting a change in the relationship between the second and third signals include instructions for determining an activity level in response to sensing an increase in thoracic fluid level and sensing an increase in a respiration rate response to the activity level compared to a previously measured respiration rate response, and
wherein instructions for setting the threshold include instructions for determining a first sensor signal level corresponding to the increase in the respiration rate response.
28. An implantable medical device, comprising:
means for sensing a first signal in a patient correlated to a first physiological condition;
means for sensing a second signal in the patient corresponding to a second physiological condition;
means for sensing a third signal in the patient corresponding to a third physiological condition responsive to the second physiological condition;
means for determining a relationship between the second signal and the third signal,
means for detecting a change in the relationship between the second signal and the third signal,
means for determining a threshold in response to the detected change in the relationship between the second signal and the third signal, and
means for detecting an event in response to the first signal crossing the determined threshold.