Process and apparatus for purging gas-containing storage tanks in vessels

Claim 2

A process for purging a storage tank, such as a tank on a tanker ship, of stored gas comprising: a. burning fuel to generate a continuous stream of gas inert with respect to said stored gas, b. dividing said continuous gas stream into first and second inert gas streams, c. directing said first inert gas stream into a storage tank to displace said stored gas from said tank, d. admixing said second inert gas stream with said displaced gas following removal from said tank to further dilute said displaced gas, and e. discharging said dilute displaced gas into the atmosphere.

Claim 3

A process according to claim 1 wherein said stored gas is combustible, a part of said stored gas being utilized as said fuel and burned to generate said inert gas.

Claim 4

A process according to claim 1 wherein said fuel is liquefied gas, said process comprising the further step of transferring a sufficient amount of the heat from the hot inert gas product of said burning to vaporize said liquefied gas fuel prior to burning.

Claim 5

A process according to claim 2 wherein said stored gas is liquefied gas, said process comprising the further step of transferring a sufficient amount of the heat from the hot inert gas product of said burning to vaporize said part of said stored gas prior to burning.

Claim 6

A process according to claim 1 wherein said stored gas is ammonia gas, said process comprising the further step of adding a portion of said ammonia gas to the inert gas product of said burning to react with CO2 in said inert gas product forming ammonium carbamate precipitate, whereby CO2 is removed from said inert gas before contacting said stored gas.

Claim 7

A process according to claim 1 comprising the further steps of cooling the inert gas with a liquid cooling medium and utilizing the heat transferred to said cooling medium to warm said fuel before being burned.

Claim 8

A process accordIng to claim 3 wherein said heat transfer step comprises passing said hot inert gas through a scrubbing liquid to cool said inert gas and subsequently passing said scrubbing liquid and liquefied gas fuel through heat transfer means to warm and vaporize said liquefied gas fuel.

Claim 9

A process according to claim 4 wherein said heat transfer step comprises passing said hot inert gas through a scrubbing liquid to cool said inert gas and subsequently passing said scrubbing liquid and said part of said stored liquefied gas through heat transfer means to warm and vaporize said stored liquefied gas before being burned.

Claim 10

Apparatus for purging a storage tank, such as a tank on a tanker ship, of stored gas comprising: a. burner means for burning a fuel to produce a gas inert with respect to said stored gas, b. scrubber means for receiving, cooling and washing said inert gas, c. conduit means (20) for directing stored gas from said tank to a location for discharge of said stored gas, d. further conduit means (9-9; 13-9) for conducting fuel from a fuel supply to said burner means, e. further conduit means for directing said inert gas from said burner means to said scrubber means, f. further conduit means (24, 26, 27) for dividing the flow of scrubbed inert gas from said scrubber means into first (27) and second (26) parts and directing said first part of said inert gas into said tank to dilute and purge stored gas in said tank and directing said second part of said inert gas to said conduit means (20) for further diluting said storage gas from said tank before reaching said location for discharge, and g. valve means to regulate flow through said conduit means, h. whereby stored gas may be diluted prior to discharge into the atmosphere and storage tanks may be safely purged.

Claim 11

Apparatus for purging a storage tank, such as a tank on a tanker ship, of stored gas comprising: a. burner means for burning a fuel to produce a gas inert with respect to said stored gas, b. scrubber means for receiving, cooling and washing said inert gas, c. conduit means (20) for directing stored gas from said tank to a location for discharge of said stored gas, d. further conduit means (9-9; 13-9) for conducting fuel from a fuel supply to said burner means, e. further conduit means for directing said inert gas from said burner means to said scrubber means, f. further conduit means (24, 26, 27) for dividing the flow of scrubbed inert gas from said scrubber means into first (27) and second (26) parts and directing said first part of said inert gas into said tank to dilute and purge stored gas in said tank and directing said second part of said inert gas to said conduit means (20) for further diluting said storage gas from said tank before reaching said location for discharge, and g. valve means to regulate flow through said conduit means, h. whereby stored gas may be diluted prior to discharge into the atmosphere and storage tanks may be safely purged.

Claim 12

Apparatus according to claim 9 wherein said further conduit means (13-9) extends from a source of fuel to said burner means for conducting said fuel to said burner means, said apparatus further comprising further conduit means (19) connecting the outlet of said tank with said scrubber means whereby any component of said inert gas capable of reacting with said stored gas may be removed by feeding stored gas from the tank into said scrubber means to react said component with said stored gas before said inert gas flows through said further conduit means (24, 26, 27) and contacts said stored gas in said conduit means (20) and in said tank.

Claim 13

Apparatus according to claim 9 wherein said further conduit means (9-9) extends from said tank to said burner means for conducting combustible stored gas to said burner means.

Claim 14

Apparatus according to claim 9 wherein said further conduit means (13-9) extends from a source of fuel to said burner means for conducting said fuel to said burner means.

Claim 15

Apparatus according to claim 10 wherein said scrubber means comprises a scrubbing tower, means for feeding scrubbing water downwardly through said inert gas in said tower to scrub and cool said inert gas, and further conduit means (15) for recycling said scrubbing water.

Claim 16

Apparatus according to claim 13 wherein said further conduit means (15) includes heat exchange means to cool said recycling scrubbing water.

Claim 17

Apparatus according to claim 13 wherein said further conduit means (13-9) extends from a liquid fuel supply to said burner means, said further conduit means (13-9) including heat exchange means in said scrubbing tower whereby the liquid fuel may be vaporized by heated scrubbing water.

Claim 18

Apparatus according to claim 10 further comprising drying means in said first part of said further conduit means (24, 26, 27) to dry said inert gas from said scrubber means before being fed to said tank.

Claim 19

Apparatus for purging a stored tank, such as a tank on a tanker ship, of stored gas comprising: a. burner means for burning a fuel to produce a gas inert with respect to said stored gas, , b. scrubber means for receivinG, cooling, and washing said inert gas, c. conduit means (20) for directing stored gas from said tank to a location for discharge of said stored gas, d. further conduit means (9-9) for directing stored gas from said tank to said burner means, e. further conduit means for directing said inert gas from said burner means to said scrubber means, f. further conduit means (24, 26, 27) for dividing the flow of scrubbed inert gas from said scrubbing means into first (27) and second (26) parts and directing said first part of said inert gas into said tank to dilute and purge stored gas in said tank and directing said second part of said inert gas to said conduit means (20) for further diluting said stored gas from said tank before reaching said location for discharge, and g. valve means to regulate flow through said conduit means, h. whereby stored gas may be diluted prior to discharge into the atmosphere and storage tanks may be safely purged.

Claim 20

Apparatus for purging a stored tank, such as a tank on a tanker ship, of stored gas comprising: a. burner means for burning a fuel to produce a gas inert with respect to said stored gas, , b. scrubber means for receivinG, cooling, and washing said inert gas, c. conduit means (20) for directing stored gas from said tank to a location for discharge of said stored gas, d. further conduit means (9-9) for directing stored gas from said tank to said burner means, e. further conduit means for directing said inert gas from said burner means to said scrubber means, f. further conduit means (24, 26, 27) for dividing the flow of scrubbed inert gas from said scrubbing means into first (27) and second (26) parts and directing said first part of said inert gas into said tank to dilute and purge stored gas in said tank and directing said second part of said inert gas to said conduit means (20) for further diluting said stored gas from said tank before reaching said location for discharge, and g. valve means to regulate flow through said conduit means, h. whereby stored gas may be diluted prior to discharge into the atmosphere and storage tanks may be safely purged.