The Model Research And Forecasting Of Scaling Process On Inner Wall Of Coll Pipe In Nature Gas Heater

Scaling is widespread in the oil and gas storage and transportation, heating ventilationand other fields. As long as the ion of scaling in solution is over saturated under a certaintemperature and pressure conditions, and there is nucleation of media, scaling will appear. Thescaling process of wet nature gas on inner wall of coil pipe in nature gas heater is a typicaltwo-phase flow scaling. This paper establishes the two-phase flow scaling model of wet naturegas, develops the forecasting program of the scaling process of wet nature gas on inner wall ofcoil pipe in nature gas heater, which can predict temperature, pressure, fouling layer thicknessand other scaling parameters. On the other hand, by changing scaling factors such astemperature, pressure, liquid flow rate and so on, the influence of scaling factors over theamount of scaling is analyzed.This paper researches how the scaling parameter changes along the direction of thepipeline when the time is 2h, 6h, 10h and 14h, and how the scaling parameter changes overtime where the position is 25m, 50m, 75m and 100m, and the different influence over theamount of scaling by changing the numerical value of scaling factors.The results showed that the wet gas temperature gradually increased along the pipedirection at the same time, the temperature gradually reduced over time in the same position,the higher the temperature on the pipe wall, the greater the amount of the scale in the wetnature gas. When the free water flow rate in the wet nature gas is larger, the actual liquidvelocity of the water phase is becoming higher, leading to increased erosion rate, the rate of fouling layer thickness is becoming smaller. The pressure along the pipe direction graduallydecreased at the same time, which also decreased in the same position over time, the higher thepressure the smaller the gas volume, the gas rate in the cross section is smaller, while the liquidholdup increases, the liquid through the cross-sectional area becomes larger, the actual liquidvelocity decreases, thereby the fouling layer thickness is increased. With the concentration of4.5kg/m³, 5.5kg/m³ and 6.5kg / m³, the result showed that when the concentration of CaSO₄ ishigher, the fouling layer thickness is greater. This paper respectively analyzed the scalingresistance of stratified flow and bubble flow , the result showed that when the flow pattern isknown, we can't qualitatively compare scaling resistances only by the flow pattern, becausethe scaling process is a complex process which is affected by many factors, we have to make adetailed calculation in order to compare the scaling thermal resistance between different flowpatterns, flow pattern is one of the factors to determine the value of scaling resistance,different flow patterns corresponding to different methods of calculating the average scalingresistance; Finally analized the scaling characteristics of wet natural gas pipeline, the netscaling rate curve of stratified flow, annular flow and spray flow along the pipeline has beencalculated, the result shows that the net scaling rate of stratified flow is greater than annularflow and that the net scaling rate of annular flow is greater than the spray flow.