Chemical Modification Of Humic Acid And Its Dispersionproperty To Coal Particles

China is rich in coal resources,oil and natural gas Relative shortage of resources.If lump coal is used directly for incineration without processing,the utilization efficiency of coal is very low,and it will seriously pollute the air and generate dust,posing a great threat to human and animal health.Coal water slurry technology burns directly compared to conventional lump coal,which is cleaner.In China's energy strategy,there is a better way to develop and utilize coal water slurry technology.To prepare high-quality,low-viscosity high-quality coal water slurry,dispersant is the key.Therefore,the study of dispersants is of great significance for the comprehensive utilization of coal water slurry.At present,the most common coal water slurry additives on the market are naphthalenesulfonic acid formaldehyde condensation polymers,as well as lignin and polycarboxylate dispersants,but the advantages and disadvantages of these dispersants are obvious.For example,naphthalene dispersants are highly polluted and the resulting slurries are poorly stable;polycarboxylate dispersants exhibit relatively high prices relative to other dispersants and are complex in process;lignin dispersants are comparable to other dispersants There are defects such as high pulp viscosity and poor fluidity.The humic acid?HA?dispersant is much less expensive than other dispersants because of its low cost,and its dispersibility is much better than that of lignin,and is widely used by various industries.However,the current research on HA has only simple chemical modification,such as sulfonation and nitration with sulfonating agent and nitrating agent,and sulfomethylation with formaldehyde?HCHO?solution and anhydrous sodium sulfite?Na₂SO₃?.Simply improve the hydrophilicity and dispersibility of the HA dispersant,but there are still many important problems,such as the molecular chain is not long enough,the relative molecular mass is too small,and the stability of the prepared coal water slurry is not good.In order to overcome the above problems,the humic acid molecules were designed by studying the structure of other dispersants,and the HA molecules were chemically modified by polymerization to synthesize the excellent dispersibility as well as naphthalene.Such a highly stable HA dispersant.Firstly,two HA polymer dispersants?HBNS and HSP?were synthesized by sulfomethylation and polymerization using HA,Na₂SO₃,HCHO solution,sodium?-naphthalenesulfonate and sodium 4-aminobenzenesulfonate as raw materials.Optimize its synthesis process conditions.The optimum process conditions for HBNS are:30%Na₂SO₃,35%?-naphthalenesulfonic acid,and 40%HCHO.The optimum process conditions for HSP are:25%Na₂SO₃ and 30%sodium 4-sulfamate.The amount of HCHO is 35%.Then,two kinds of coal water slurry dispersants were characterized by FT-IR,XPS,XRD,TGA,DSC,SEM and GPC.It is used for Yulin coal pulping and its application performance test of dispersant.The results show that when the addition amount of HBNS dispersant is 0.5wt%,the viscosity of coal water slurry is at least 513 mPa·s,the highest pulp viscosity is 68wt%,and the instability index of coal water slurry system is 0.2915.The water-dissolving rate was 5.25%for 7 days,the saturated adsorption amount was3.966mg/g,the optimum addition amount of HSP dispersant was 0.6%,the viscosity of coal-water slurry was 497 mPa·s,and the highest pulp viscosity was67wt%.The instability index of the coal water slurry system is 0.3180,the water separation rate after standing for 7 days is 5.87%,and the saturated adsorption amount is 3.765 mg/g.Compared with the common dispersing agent sold on the market,the results show that the pulpability of the newly prepared HA coal water slurry dispersant is indistinguishable from that of the naphthalene system,but the stability of the prepared coal water slurry is more than that of the naphthalene dispersion.The agent is much higher;and the newly prepared HA coal water slurry dispersant is more cost-effective and effective than the coal water slurry dispersant currently on the market.It has been explored how the properties of the dispersant and the performance of the coal water slurry interact with each other.Since the HA dispersant is sensitive to soluble metal ion minerals,the influence of various metal ions on the dispersibility of the HA dispersant is also explored.From the experimental results,the metal ion concentration is higher for different metal ions.The higher the valence state,the greater the slurrying effect of the coal water slurry prepared by its HA as a dispersant.In conclusion,this thesis has certain reference value for the research of HA dispersant and coal water slurry.In this paper,two highly dispersible,low-cost HA coal water slurry dispersants were synthesized,and the basic unit structure of HA and its The interaction between various functional groups and coal molecules in the structure is explained through experiments and theoretical knowledge,and the basic principles of its action are explained and explained in detail.It will be helpful for the future research of coal water slurry or HA dispersant..