Researches On The Preparation Of Oil Soluble Drag Reducer By Slurry Polymerization And Its Application Techniques

Oil soluble polymeric drag reducer is one of the vital chemical additives in the petroleum pipeline engineering.In current days,the synthesis process of drag reducer in China is mostly the bulk polymerization.The controllability of the bulk polymerization is poor,and the synthesized super-high molecular drag redution polymer is a viscoelastic solid at room temperature,which requires to be stabilized and dispersed in organic solvents(dispersants,stabilizers and other substances are often added)before it can be injected into the oil pipeline.However,at present,the encapsulated drag reducer was developed abroad,although the post-treatment process is relatively simple,but the preparation process is complex,which requires simultaneous polymerization of the drag reduction polymer as capsule and the polyurethane as shell.Some of the raw materials used are toxic.Therefore,it is imperative to develop a simple post-treatment and high efficient oil soluble drag reducer preparation process that is user-friendly and environmental-friendly.In this paper,with using the silicone oil as the inert solvent,a new technology of slurry polymerization drag reducer was developed,and the key technology of the preparation of slurry polymerization drag reducer is studied.The main work and conclusions are as follows:(1)A novel technology of slurry polymerization drag reducer preparation was developed.In the slurry polymerization process,the Silicone oil is an inert solvent.With the inertia and lubrication characteristics of silicone oil,it can form a layer of protective film on the surface of polymer in precipitation,which reduces the probability of the polymer particles adhering together into pieces.Finally the polymer was suspended in silicone oil system as single loose particles.The technology is slow in heat release and not easy to detonation.The synthesized drag-reducing polymer is dispersed directly in silicone oil in the form of fine particles,which reduces the difficulty of post-treatment of drag-reducing agent.(2)Research on the slurry polymerization drag reducer optimized preparation was carried out.First,the effects of the main catalyst on the molecular weight and particle size of the synthesized drag reducer were studied experimentally,and the type and particle size of the main catalyst were optimized according to the results.Then in the main catalyst for certain conditions,inspected the cocatalyst,outside to electronic,polymerization temperature,the system of moisture,polymerization time,stirring conditions and different polymerization monomer ratio on the properties of the synthetic polymer drag reduction effect,found that the catalytic systems(main catalyst + main catalyst)and the proportion of the concentration and the impurity in the reaction system of water content are two important influencing factors.The amount of the catalyst filling leads to excessive number of active center,lowering the molecular weight of polymer;when the catalyst content is too low,though the molecular weight of the polymer will be improved,the conversion rate of the monomer will be reduced.The water content in the reaction system will affect the activity of the catalyst and lead to the deactivation of the catalyst.Finally puts forward the optimized polymerization conditions,the control system of water content is less than 25 mg/L,temperature of-10 ?,tri-isobutylaluminum(TIBA)as the catalyst promoter,the dicyclopentyldimethoxysilane(DCPDMS)as the electron donor,the molecular weight of the polymer obtained will more than 4 million.(3)Research on the post-treatment optimization of slurry polymerization drag reducerw as carried out.Suspension slurry of anti-drag polymer was prepared with isooctyl alcohol,N,n-dimethylformamide(DMF)as the dispersing medium and ethylene bistearamide(EBS)as the isolating agent.The stability of slurry polymerization products in the suspension was investigated,and the distribution ratio and preparation conditions of the slurry polymerization drag reducer were finally determined to ensure that the oil soluble drag reducer prepared can be stored for more than 90 days without obvious stratification.(4)A comprehensive evaluation system of drag reducer to product oil was established,which includes with using the loop to make mixtures of drag reducer and refined petroleum products,analyzing the performance indexes of the additive oil,the stage test and the car test.It is shown that the total insolubles in diesel increase gradually over time,the stability of diesel oil become badly,and the viscosity and hexadecane number index change little.This evaluation system has been proven to be a practical and effective way to evaluate refined oil products and drag reducer,ensuring the safety and reliability of the application of the drag reducer.(5)After the drag reducer dissolves in oil,the drag reduction function can be achieved.By studying the different oil viscosity,dosages of drag reducer and dissolving temperature,the dispersion patterns of drag reducer in oils were revealed.Dispersing time mainly increases with increasing oil viscosity and concentration of additive.The effect of raising the temperature on the dispersants is to increase the dissolution rate of the drag reducer in the oil,was by accelerating the brown movement of the molecules of the drag reducer.With the study,a formula for predicting drag reduction based on dispersion time is proposed.(6)For the short-distance pipelines,a kind of dispersing pipe-adding device was developed.The drag reduce can be pre-dispersed through the dispersing pipe-adding device,which can effectively shorten the effective time of the drag reducer in the pipeline and improve the application effect of the drag reducer.The application of the diesel pipeline in Qingdao has shown that it can be effective to reduce the dispersing time of the drag reducer,and it has obvious effect on increasing the throughput and reducing friction of short distance pipeline.Compared with the direct dosing method,the dosing method of dispersing pipe-adding device can achieve the same effect at a lower dosage.(7)A comparative experiment was conducted in the Hong-jing oil pipeline to analyze the difference between the slurry polymerized drag reducer and a foreign import drag reducer.Field test results show that: the loading effect of the imported agent was slightly better than that of the slurry agent,which was about 10% ? 20% higher than that of the same dosage.But with the gradual increase of the total amount of dosage,the difference between the imported agent and the slurry agent gradually decreases.Therefore,from the perspective of economic benefits,when the total amount of adding agent is larger,it is more economical and reasonable to use the slurry polymerized drag reducer.Within the maximum increasing transport capacity of the pipeline,the comprehensive rate of return achieved by adding drag reducer in the pipeline is positive.Adding 114 mg/L slurry polymerized drag reducer in the pipeline can increase the transport capacity to 1.2 ×104 t/d,the incremental transport economic benefit generated in the year of conversion is about 35 million RMB per year,and the incremental transport benefit is very significant.