Application case of a natural gas processing plant in Changqing Oilfield

As a large-scale natural gas ethane recovery unit in China, a natural gas processing plant in Changqing Oilfield is a key project for PetroChina to improve quality and efficiency. To achieve ethane production as soon as possible

The raw material supply for the ethylene project not only adopts advanced "refrigerant refrigeration+expansion refrigeration+double gas subcooling+low-temperature distillation" ethane recovery and treatment main process technology, but also

Moreover, in engineering design and construction, we fully leverage the overall advantages of PetroChina, utilizing advanced SP3D 3D collaborative design platform and "full lifecycle digitization"

The "factory" mode has achieved digital and intelligent management of the entire process of design, procurement, construction, and operation and maintenance. At present, the completed natural gas processing plant can achieve an annual processing capacity of days

20 billion cubic meters of natural gas, with an annual production of 1.05 million tons of ethane, 450000 tons of liquefied petroleum gas, and stable light hydrocarbons, equivalent to the output value of a medium-sized domestic oil field

It also signifies that China's natural gas development has not only completed the transformation from scale based to efficiency based development, but also achieved high-quality closed-loop development of PetroChina in the Shaanxi industrial chain.

The closed cooling tower system for circulating water in the natural gas treatment plant adopts a combination of air cooling and water cooling to cool the circulating water. Due to the use of underground cooling water for the closed-loop cooling tower of circulating water

Water is directly used as supplementary water, and after concentration, the scaling trend of the system is obvious. It is easy to deposit and adhere on the cooling tower packing, spray device, and heat exchange tube, which affects the heat transfer effect and leads to internal scaling

The decrease in circulating temperature difference does not achieve the expected heat transfer effect. Due to the adhesion and deposition of scale and biofouling, corrosion under the scale is easily formed, which may lead to the formation of heat exchange tube bundles in cooling towers in severe cases

Becoming a leakage point. After on-site investigation, it was found that the external circulation spray water system had already experienced scaling.

The conductivity of the spray water replenishment is 2290 μ s/cm, and the total mineralization is 1705.08mg/L, which is higher than the designed 1000mg/L. When the spray water is constantly evaporating and replenishing water

After running for 1 hour under operating conditions, the conductivity increased from 2290 μ s/cm to 10140 μ s/cm, with a nearly 5-fold increase in conductivity. The total mineralization increased from 1705.08mg/L to

3880.07mg/L, The concentration multiple reaches 2.3 times. When the spray water is not replaced, the conductivity can reach 34900 μ s/cm after 48 hours of operation, and the concentration multiple reaches

About 30 times. Therefore, in the case where the spray water quality does not meet the standard and water quality pretreatment is not carried out, the spray water is packed in the closed cooling tower of the circulating water heat exchange tube bundle and the spray water main pipe

And serious scaling and crystalline salts are formed in the spray water tank, leading to a decrease in the heat transfer efficiency of the circulating water spray, blockage of the packing, insufficient air intake of the air cooling fan, and reduced air cooling effect.

To solve For the above issues, our company has installed an induction type conductivity online measuring instrument in its cooling tower to monitor the conductivity of the spray water in real time. When the spray water quality does not meet the standard

In the absence of water quality pretreatment, activate the alarm to provide accurate basis for subsequent water treatment and sprinkler water replenishment.

The induction conductivity electrode produced by Shanghai Botuo Instrument Co., Ltd. has a large measurement range and anti scaling characteristics, which solves the problem of high mineralization of water samples on site

The problem of sensor scaling generated greatly reduces the frequency of on-site personnel maintenance and reduces the workload of on-site operation and maintenance personnel. Its ultra large range of 0-2000ms/cm,

Covering the measurement requirements required on site.