| A large amount of oily wastewater will be produced during the exploitation and processing of petroleum.Oily wastewater has the characteristics of large oil content,strong stability,complex composition,poor biodegradation and great difficulty in treatment.The direct discharge of oily wastewater will not only waste precious petroleum resources but also cause great threat and damage to human health and the environment.Offshore platform wastewater treatment requires fast oil-water separation,moderate floc strength,and a small amount of medicament.According to the relationship between polymer molecular structure and performance,template polymerization and inverse emulsion polymerization are used to synthesize micro-block crosslinked and micro-crosslinked cationic polyacrylamide copolymers.The Two prepared multi-branched cationic polyacrylamide copolymers were characterized and evaluated for their flocculation performance.The main work is summarized below:1.A micro-block crosslinked cationic copolymer TPADV was synthesized vis free radical template polymerization by using acrylamide(AM)and acryloxyethyl dimethyl benzyl ammonium chloride(DBAC)as polymerization monomers,anionic water-soluble linear sodium polyacrylate(NaPAA)as a template,and a trace amount of vinyl alkoxy VTMES as a cross-linking monomer.The product was characterized by HNMR,charge density,apparent viscosity,static light scattering,etc.to investigate the influence of template on polymer performance.The results showed that the template polymerization method can make the cationic monomers oriented along the template chains to form a cationic micro-block structure,which increased the charge density of the polymer;the addition of vinyl alkoxy silane formed a micro-crosslinked high molecular weight The copolymer enhanced the adsorption bridging effect.Taking the deoiling rate of oily wastewater as the main indicator,the best preparation process for TPADV has been determined as follows:Va-044 was used as the initiator,the polymerization temperature was 55?,nAM/DBAC ratio was 2:1,and nNaPAA/DBAC ratio was 0.1.The added amount of VTMES was 1%of the total monomer mass.The flocculation performance was evaluated.The experimental results showed that when the amount of TPADV3 copolymer was 60 mg/L,the deoiling rate of simulated oily wastewater can achieve 95%.the deoiling rate of the wastewater from the Bohai K oil field could achieve 95%when the amount of TPADV3 copolymer was 300 mg/L,and the solution was kept at room temperature for 2 hours,and the oil floc had suitable floc intensity and high recovery factor.Using TSI to analyze the flocculation process,it was found that the instability index was relatively high and the flocculation time was short.The NPADV type flocculant maintained a high oil removal rate,and the oil flocs after treatment had suitable floc strength and recovery factors.2.A slight cross-linked multi-branched cationic copolymer(PADTV)was synthesized vis free radical inverse emulsion polymerization by using acrylamide(AM)and methacryloxyethyl trimethylammonium chloride(DMC)as polymerization monomers,trimethylolpropane triacrylate(TMPTA)as a branching initiator,vinyl triethoxysilane(VTMES3)as a trace cross-linking monomer.,HNMR and charge density were carried out to study the effect of branching initiator on polymer performance.The results showed that the obtained copolymer achieved an increase in the utilization rate of polymer cation charges and an adsorption bridging effect by using TMPTA as a branching monomer,and introducing a trace amount of alkoxysilane to regulate the molecular weight of the polymer through micro-crosslinking.Taking the deoiling rate of oily wastewater as the main indicator,the best preparation process of PADTV has been determined as follows:Va-044 was used as the initiator,polymerization temperature was 55?,nAM/DMC is 1:1,the added amount of branching initiator TMPTA was 0.5%of the total monomer mass,and the added amount of vinyl alkoxy silane(VTMES3)was 0.4%of the total monomer mass.The flocculation performance of PTADV copolymer was evaluated.The experimental results showed that when the PADTV6 copolymer was added at 50 mg/L,the deoiling rate of simulated wastewater could achieve more than 94%;when the PADTV6 copolymer was added at 300 mg/L,after being kept at the room temperature for 2 hours,the de-oiling rate of the wastewater from the Bohai K oilfield could achieve 96%,and the oil flocs had suitable floc strength and high recovery factors.Using TSI to analyze the flocculation process,it was found that the instability index was relatively high and the flocculation time was short. |
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