During the transportation of the natural gas gathering station

due to the constantly change of the temperature and pressure

it is easily to occur the hydrate

resulting in the clogging of the pipeline and affecting the normal transportation of natural gas. The main way is injecting the methanol when the natural gas by the gathering station. According to the situation of Zizhou gas gathering station

we used the process model of

"

the separation at room temperature in small station

transportation as moisture vapor

and concentrated dehydrocarbon and dehydration in processing plant

"

. In order to determine the reasona

ble methanol injection quantity and optimize the methanol injection system

firstly

we measured and compared the water dew point and the ambient temperature of the natural gas at the inlet and outlet of the separator at each level to determine whether methanol injection is needed. If the methanol was needed

we would take the maximum difference calculated between the gas dew point at each stage of the gas separator and receiver

and the corresponding ambient（pipeline） temperature as the maximum temperature difference that need to be optimized. Then

we used the industry standard dew point correction chart to establish the dew point correction model. Finally

based on the maximum temperature difference to be optimized

we determined the optimum methanol injection amount by the correlation analysis between the methanol injection volume and the temperature correction value in the gas gathering station of Zizhou gas field. The obtained methanol injection volume can effectively inhibit the formation of hydrate and save the cost. The final recommended table for methanol injection volume suitable for the gas gathering station in Zizhou gas field can be used to guide the production.