What is a Collection Ratio?

Recovery rates include absolute and relative rates. Absolute recovery looks at the proportion of drugs that can be used for analysis after sample processing. Because whether it is a biological matrix or a drug in a formulation excipient, there is a certain loss after sample processing.

The absolute recovery rate is because the drug

1. Determination of the content of the drug substance can be determined with a reference substance of known purity or a drug substance that meets the requirements, or the results obtained by this method can be compared with established results.

LNG is transported by a gas source unit using a tank truck. The tank truck is weighed before the gas source plant leaves the vehicle. This is the incoming weight. The tank truck arrives at the natural gas company and is unloaded before weighing. This is According to the actual weight, LNG is abbreviated as LNG, and its main characteristic is -162 ° C, which is liquid, and it can be converted into gaseous state as the temperature rises; conversely, gaseous natural gas can be converted into liquid state as the temperature decreases. The volume ratio of gas-liquid conversion is about 600: 1, that is, 1m ³ of liquefied natural gas can be converted into 600m ³ of gaseous natural gas, so the two phases of gas-liquid can be switched. According to the physical and chemical characteristics of LNG, when the temperature gradually increases, -162 ° C LNG will be converted into a gaseous form. Similarly, when the temperature is gradually reduced, gaseous form of natural gas will also be converted into a liquid form. The remaining natural gas in the gaseous form is converted into a liquid state and transported to the storage tank, so that the remaining natural gas in the tanker can be unloaded as much as possible to avoid losses, so the most critical thing to convert the gaseous form to the liquid form is to control And reduce the temperature of the gaseous natural gas, so that the gaseous form of natural gas in the car is converted into the liquid form as much as possible. ^[2]

According to the process equipment and pipeline conditions in the station, there are a total of 3 pipelines connected to the storage tank, one is a gas phase pipeline, one is a pipeline that transports natural gas to the tank to enter the liquid tank, and one is a pipeline that outputs natural gas to the storage tank. ; According to the internal structure of the storage tank, the liquid inlet pipe for the tank truck to transport natural gas enters from the top of the storage tank, and the liquid outlet pipe for the tank to transport liquefied natural gas is output from the bottom of the storage tank. Natural gas is in direct communication with the liquefied natural gas in the storage tank. A bypass pipe and valve are added between the liquid inlet pipe and the liquid outlet pipe. To this end, according to the operating situation, the bypass valve can be opened in time to connect the liquid outlet pipe. Connect with the inlet pipe. After the bypass pipes and valves are added, the process operation steps are also relatively adjusted, as follows:

1.Before improvement

(1) When the tank truck begins to unload, open the tank inlet pipe valve and tank tank outlet valve to transfer the LNG in the tank truck to the tank.

(2) At the end of the unloading, the pressure in the tanker slowly decreases, and when it is basically the same as that in the tanker (about 0.4 Mpa), the unloading is completed.

After improvement

(1) When the tank truck begins to unload, open the tank inlet pipe valve and tank tank outlet valve to transfer the LNG in the tank truck to the tank.

(2) At the end of the unloading, the pressure in the tanker slowly decreases, and when it is basically the same as that in the tanker, the liquid inlet valve of the storage tank is closed, and the bypass pipe valve and the liquid outlet valve of the storage tank are opened at the same time, so that the natural gas transported by the tanker Enter from the bottom of the storage tank and directly contact the remaining gaseous natural gas of the tanker with the liquefied natural gas in the storage tank, so as to achieve the purpose of gaseous liquid conversion.

(3) Until the pressure in the tank car drops to 0.2 Mpa (a little pressure must be maintained in the tank car as required), close the tank car and storage tank valves and unload the car. After improving the process operation, through several months of data statistics, the recovery rate has improved significantly. ^[2]