Carrying method of crude oil and naphtha by dirty/crude oil carrier, and transfer method of the crude oil and naphtha from the carrier

Abstract

To provide a transfer method of crude oil and naphtha, in which one piping is used to transfer the naphtha and crude oil to a storage tank from a carrying tank in batches. To use a piping 53 to transfer a naphtha 3 to tanks 6 for the naphtha from inboard tanks 11 , a method comprises: connecting the piping 53 to the tanks 4 for the crude oil; calculating the amount of the crude oil 2 remaining in the piping 53 beforehand; discharging the naphtha 3 from the inboard tanks 11 ; measuring the discharge amount; and stopping the discharge of the naphtha 3 , changing to the tanks 4 for the crude oil, and restarting the discharge of the naphtha 3 based on a flow analysis of a mixed fluid 7 including the crude oil 2 and naphtha 3 in the piping 53 , when the discharge amount of the naphtha 3 is substantially the same as the pre-calculated amount of the remaining crude oil 2.

1 . A carrying method of naphtha using a carrier which carrying crude oil, comprising the steps of: 
 designating at least some of a plurality of carrying tanks disposed in said carrier as tanks for carrying the naphtha;    washing the inside of said carrying tank for carrying the naphtha before loading the naphtha; and    draining the crude oil from at least a piping on said carrier during loading or unloading of the naphtha to load or unload said naphtha.    
   
   
       2 . The carrying method of the naphtha by the carrier according to  claim 1 , wherein said step of washing the inside of said carrying tank for carrying said naphtha includes steps of washing it with the crude oil.  
   
   
       3 . The carrying method of the naphtha by the carrier according to  claim 1  wherein said carrier is a crude oil supertanker exceeding 100,000 deadweight tons.  
   
   
       4 . The carrying method of the naphtha by the carrier according to  claim 1 , wherein the steps of designating carrying tanks include steps of avoiding said carrying tank connected to a drain for draining the crude oil in said piping to designate the carrying tank for carrying the naphtha.  
   
   
       5 . The carrying method of the naphtha by the carrier according to  claim 1  wherein said step of loading the naphtha includes the steps of slowly loading said naphtha at a speed at which a crude oil residue sometimes remaining in a bottom of said carrying tank is not stirred at an early stage immediately after starting the loading.  
   
   
       6 . The carrying method of the naphtha by the carrier according to  claim 1  wherein said step of unloading the naphtha includes the steps of unloading said naphtha at a speed at which the crude oil residue sometimes remaining in the bottom of said carrying tank is not stirred.  
   
   
       7 . The carrying method of the naphtha by the carrier according to  claim 1 , further comprising the steps of: determining the number of said carrying tanks for use in accordance with a load capacity of said naphtha; and designating said carrying tank for carrying said naphtha so as to inhibit a center of gravity of said carrier from moving because of a difference in density or specific gravity between the crude oil and naphtha.  
   
   
       8 . A method of carrying crude oil and naphtha with a common carrier and transferring the crude oil and naphtha to a storage tank from a carrying tank by one piping, comprising the steps of: 
 (1) using said piping to discharge the naphtha or crude oil to said storage tank from said carrying tank, while said piping is connected to a tank for the crude oil or naphtha;    (2) calculating an amount of the crude oil or naphtha remaining in said piping via which said carrying tank is connected to the storage tank beforehand;    (3) discharging the naphtha or crude oil from said carrying tank, and measuring a discharge amount;    (4) stopping the discharging of the naphtha or crude oil from said carrying tank and changing a receiver tank to the tank for the naphtha or crude oil from the tank for the crude oil or naphtha, when the discharge amount of the naphtha or crude oil from said carrying tank is substantially the same as the pre-calculated amount of the crude oil or naphtha remaining in said piping; and    (5) restarting the discharging of the naphtha or crude oil from said carrying tank after changing said tank, and storing naphtha or the crude oil into the tank for naphtha or the crude oil.    
   
   
       9 . The transfer method of the crude oil and naphtha according to  claim 8 , further comprising the steps of: analyzing a flow of the crude oil, the naphtha, and a mixed fluid including the crude oil and naphtha in said piping; and using the flow analysis result to determine a timing at which the discharging of the naphtha or crude oil from said carrying tank is stopped.  
   
   
       10 . The transfer method of the crude oil and naphtha according to  claim 8  wherein the step of calculating the amount of the crude oil or naphtha remaining in said piping beforehand includes the steps of using at least a temperature, density, or specific gravity of the remaining crude oil or naphtha as a correction element.  
   
   
       11 . The transfer method of the crude oil and naphtha according to  claim 8 , further comprising the steps of: using a fixed scale of said receiver tank to measure the discharge amount of the naphtha or crude oil from said carrying tank.  
   
   
       12 . The transfer method of the crude oil and naphtha according to  claim 8 , further comprising the steps of: changing the discharge speed of the naphtha or crude oil based on said flow analysis result, when pushing out the crude oil or naphtha remaining in said piping into the tank.  
   
   
       13 . The transfer method of the crude oil and naphtha according to  claim 12 , further comprising the steps of: changing the discharge speed of said naphtha or crude oil immediately after starting the discharging of said naphtha or crude oil and immediately before stopping the discharging.  
   
   
       14 . The transfer method of the crude oil and naphtha according to  claim 13 , further comprising the steps of: rapidly raising the discharge speed of said naphtha or crude oil immediately after starting the discharging of said naphtha or crude oil up to a predetermined discharge speed.