Property Evaluation Of Natural Gas Drag Reduction Agent And Atomization Rejection System Study

Drag Reduction can be achieved by rejecting DRA into the gas pipeline. But thistechnology is in developing phase at home and abroad at present. Some developed DRA havenot been applied into industrial pipeline. Before industrial application of DRA, thecomprehensive property evaluation is an indispensable step. This has important significancefor guiding the regulation of formulation and selecting the DRA samples. Atomizationrejecting DRA has a long protection distance, operates on-line, and is easy to recovering theagent. It is suitable to be applied into industrial pipeline. So the study of atomization rejectionprocess and system has important significance for legitimately using DRA.In this paper we studied the film-forming properties of the seven newly developed gasDRA samples about three kinds. We tested the film thickness of the DRA samples byweighing method and observed the film morphology by electron microscope scanning. Thetest drew a conclusion that these three kinds of DRA samples all have good potential of dragreduction. The Gemini type DRA samples especially OPDO demonstrated best homogeneousdegree and tempered film thickness. The Bola type DRA samples had uneven but thick film.Designed and built an indoor loop system for natural gas DRA evaluating. This systemcan control temperature and simulate the low temperature environment of seabed. The systemrejection mode is variable and the agent can be recovered. We determined the drag reductionmethod by contrasting friction coefficient on the basis of the system. By the hydraulicanalysis of the system we concluded that the gas flow pattern is in drag square area and theshear stress of the system pipeline is similar to the industrial pipeline. So the indoor loopsystem could simulate the industrial pipeline.We carried out the static evaluation experiment to evaluate the seven kinds of the DRA samples in the evaluation system. By the experiment we concluded that drag reduction effectof ammonium salt of phosphonate ester of AEO-9was best at room temperature, dragreduction effect of the Gemini type DRA was somewhat less and the drag reduction effect ofBola type DRA was worst. The diethylenetriamine ammonium salt of phosphonate ester ofPEG400made the resistance of system pipeline increases. Drag reducing efficiency ofammonium salt of phosphonate ester of AEO-9reached13.7%and maintained at13.0%at131Nm3/h volume flow rate and10%concentration. The experiment showed the dragreducing efficiency was bigger at high flow rate. We carried out the static evaluationexperiment at low temperature for the three kinds of the DRA samples which had goodefficiency at room temperature. We find that the ammonium salt of phosphonate ester ofAEO-9made the resistance of system pipeline increases at low temperature because of thebad solubility and stability. The Gemini type DRA samples had good drag reduction effect atlow temperature. Drag reducing efficiency of OPDO reached10.0%and maintained at8.0%at131Nm3/h volume flow rate and10%concentration at low temperature.Then we carried out the atomization filling dynamic experiments for OPDO. By theexperiment we concluded that the drag reduction effect of DRA was bad when theconcentration was too high or too low. There have a best concentration for the DRA and isabout10%for OPDO. Drag reducing efficiency of OPDO with3hours rejection time reached15.7%at10%concentration and4L/h rejection rate. The pipeline which has short distancewith the rejection point had bad drag reduction effect because that the atomized droplets’suneven distribution made uneven film even fluid accumulation. The rejection quantity couldpromote drag reduction effect within a certain range. Carried out adsorption and activationexperiment of the zeolite for OPDO and concluded that the OPDO had no effect on theadsorption and activation property of the zeolite. The zeolite could be reused repeatedly.