Design And Application Of Cloud-Air-Purifying Technology In The Exhaust Gas Dust Removal Of Fcc Catalyst Production Unit

Fluid Catalytic Cracking(FCC),one of the most basic procedure in the petroleum refining process where heavy oil was transformed into cracked gas,gasoline and diesel under the action of heat and catalyst.And FCC catalyst plays a vital role in this process.However,as two essential procedures in the process of FCC,the spray drying and roasting process will produce exhaust mixing with lots of dust particles.Though the applying of Quench Tower and Absorption Tower can remove a part of the catalyst particles,restricted by the efficiency of the processing equipment,there still exists some finer catalyst cannot effectively captured and discharged into the air with the exhaust gas.Thus,after the on-site investigation of FCC catalyst system and demonstration of technical scheme,this paper designs a Cloud-Air-Purifying to treat the dust-exhaust tail gas(50000m~3/h)in the spray drying and roasting process so as to achieve high-efficiency capture of fine particles.The content of this paper includes the following aspects:Firstly,the outlet dust concentration of the original system was calibrated.The results show that the average dust concentration discharged by the system was95.93mg/m3,and the highest was 279.5mg/m~3.And the basic characteristics of dust particle accumulation,particle size distribution and hydrophilic were obtained by analyzing the physical properties of FCC catalyst dust particles.Secondly,the overall process design and selection of the Cloud-Air-Purifying is carried out according to the on-site working conditions of FCC catalyst,including process route design,cloud dust removal system cleaning system design,dust removal pipeline design,induced draft fan selection and automatic control system design.Thirdly,the analysis of the application effect of Cloud-Air-Purifying is done based on the field tests.This paper chiefly studies the influence of fan frequency and atomized water amount on the dust concentration at the exit of the Cloud-Air-Purifying.The results show that with the increase of the frequency of the induced draft fan,the outlet dust concentration shows a downward trend,while with the increase of atomized water volume,the dust concentration at the exit first showed a downward trend and then upward.When the system induced draft fan frequency is greater than 40Hz and the atomized water volume is 1.2~3.52m~3/h,the outlet dust concentration is lower than the standard value of 20mg/m~3.When the optimal atomized water quantity is 2.52m~3/h,the lowest value of 6.49mg/m~3 appears at the outlet.Finally,the research and overall optimization on the debugging process of the Cloud-Air-Purifying,such as equipment surface vibration and depression,high moisture content in the system outlet,intermittent water,etc.,were completed.Additionally,the application effect and the third party testing results show that the dust concentration of the spray,roasting system discharge of mean value of 8.78mg/m~3,will meet the latest national environmental standards(?20 mg/m~3).In addition,the Cloud-Air-Purifying can save the equipment investment cost of 11.54million yuan for the enterprise,and save the operating cost of the company by 2.372million yuan per year,and the economic benefits are very significant.Generally,the Cloud-Air-Purifying can achieve efficient collection of fine dust in FCC catalyst exhaust.Meanwhile it can be well applied to the exhaust gas treatment field of FCC catalyst production equipment,and provides a technical reference for the treatment of tail gas in the FCC catalyst industry.