Study On The Process Of Desulfurization And Subsequent Utilization Of The By-product Acid Slag Of Lubricating Oil

The acid slag produced in industrial lubricating oil refining process with concentrated sulfuric acid is serious pollution. Acid slag untreated contains high sulfur and leads to serious environmental pollution through soil, air and water, but also a waste of resources. So the acid slag waste desulfurization and utilization of resources, not only has the environmental benefit, also has the certain economic efficiency and social efficiency. In this paper, a lubricating oil company by-product acid slag was regarded as the object and the following research were did:analysis of acid slag, desulfurization process and the subsequent use.1. According to the analysis of the content of sulfuric and fused ring sulfonic acid two kinds of acid sludge pretreatment method were proposed:solvent method and neutralization method, then ion chromatography method and gravimetric method were respectively used to determine the sulfuric acid root and sulfonic groups and compared. The analysis results show that, for the determination of sulfuric acid root content in acid slag, the relative standard deviation of solvent method and analysis results was less than 1% and the data is accurate and reliable, but the operation process of the solvent method is simpler. So the solvent method is more suitable to apply to the determination of sulfate content in acid slag. For the determination of content for the sulfonic acid, the relative standard deviation of neutralization method is less than 1%, so it is suitable for determination of sulfonic acid content in acid slag.2. For acid slag desulphurization thermal cracking desulfurization process and alkali desulfurization process were developed, and have been carried on the experimental research. The effects of reaction temperature and reaction time on the acid slag desulfurization were discussed in acid sludge thermal cracking desulfurization process. The experimental results show that in certain reaction time the sulfur content in the product decreased with reaction temperature increased; at certain reaction temperature the sulfur content decreased with reaction time increased,so the most suitable conditions for the reaction temperature is determined: 160℃, the reaction time was 100min, and under this condition acid slag sulfur content decreased from 11.07% to 4.12%.The factors influencing the reaction system in acid slag alkali fusion desulfurization process was explored the factors under the hydrous and anhydrous conditions. Under hydrous conditions the effect of the concentration of sodium hydroxide was investigated. The experimental results show that, when the mass fraction of NaOH was low, acid residue desulfurization effect was not obvious; when the mass fraction of NaOH is higher than 70%, the sulfur content of acid slag desulfurization products fell sharply. When the mass fraction of 100%,the sulfur content reached to 1.72%.The effect of the reaction temperature and the solid sodium hydroxide excessive percentage were explored under anhydrous conditions. The experimental results show that, the sulfur content of reaction products decreased gradually with the increase of the reaction temperature; sulfur content decreased gradually with the excessive percentage increased. So the best process conditions of acid slag alkali fusion reaction for the desulfurization is reaction temperature 360℃, sodium hydroxide amount over 40%, and under this condition sulfur content decreased to1.71%.3. The catalytic cracking and separation process of the acid slag desulfurization products were simulated using Aspen Plus and the parameters of acid slag catalytic cracking process, separation process and the process flow. To integrate ethylene distillation process, propylene distillation process and utility i, two separate heat pump distillation process were used to optimize the design of the. Through the simulation calculation shows that, compared with the conventional ethylene tower and the propylene tower distillation, for ethylene distillation and propylene distillation respectively using B type heat pump distillation and A type heat pump distillation can save the cold utilities 44.30% and heating utility 0.64%; and the curve parallel degree is better than before of the cold and hot flows in the T-H graph. It showed that the new process achieved a reasonable the use of energy.