Heat Transfer Simulation And Performance Test Study On Smoldering Treatment Unit Of Oily Sludge

A large amount of oily sludge is often produced in the process of crude oil exploitation,gathering and transportation of oil fields and sewage treatment.If sludge is discharged directly without treatment,it will not only waste land resources,but also pollute water,soil and air with the toxic substances it contains.When it is directly used for reinjection and circulating in the sewage treatment system,the water quality of the injected water will decline and the operating conditions of the sewage treatment system will deteriorate,causing unpredictable losses to the production.Therefore,reasonable disposal of oily sludge is very necessary.Smoldering treatment is a new technology of oily sludge treatment abroad in recent years.Compared with other methods,it has the advantages of simple process,simple operation,rapid treatment and low treatment cost.This paper takes the smoldering treatment of oily sludge as the research object,adopts FLUENT software to carry out design optimization,and designs and produces a set of detachable experimental devices for smoldering treatment of oily sludge.The single factor method was used to explore the regularity of the experiment,and the temperature conditions and treatment effect of smoldering treatment of oily sludge under different oil content were determined,so as to provide data reference for the application of smoldering treatment of oily sludge in engineering practice.1.Design a detachable experimental device for smoldering treatment of oily sludge.The basic design and calculation of the experimental system are carried out according to the field data of the oil field,and the shape and size of the main smoldering furnace are determined.According to the amount of sludge and the amount of gas discharged,the gas cooling unit,gas-liquid separator and activated carbon treatment box were selected.Draw CAD engineering design drawings of the experimental system and determine the specific parameters of each equipment.2.Combined with heat transfer simulation,optimize the selection of heating device and air supply device.FLUENT was used to simulate the heat transfer in the combustion chamber under different air fluxes and heating temperatures.The air flux in the combustion chamber was controlled to be 7cm/s,and the power of the cast copper heating plate was adjusted to obtain the highest heating temperature in the combustion chamber,which was compared with the theoretical smoldering ignition temperature.The simulation results show that when the heating plate power reaches 1150W,the maximum temperature of the combustion chamber can reach 500℃,which meets the requirements of general smoldering ignition temperature of oily sludge at 450℃.When the heating plate power reaches 1500W,the maximum temperature of the combustion chamber can reach 650℃,which meets the ignition requirements of most oily sludge that can be smudged.Therefore,the maximum heating power of the heating plate is 1500W,and the heating temperature of the heating plate can be adjusted through the PLC temperature control box.Otherwise,the heating temperature of the copper casting heating plate was controlled at 450℃,and the air flux in the combustion chamber was adjusted to obtain the temperature distribution in the combustion chamber under different air fluxes.When the air flux is higher than 20cm/s,the maximum temperature in the combustion chamber is already lower than 410℃,which is not conducive to smasher ignition and self-sustaining propagation of smasher front.The ideal air flux is between 7-13cm/s,so the maximum designed air flux is around 13cm/s.3.The smoldering experiment system was used to explore the smoldering law of oil sludge under different oil content.The smoldering condition of sludge under different oil content was analyzed and studied by using single factor method.The experimental conclusion is:when the oil content of oily sludge is below 40g/kg,smoldering can be ignited,but it cannot be self-sustainably advanced.Smoldering can be maintained by means of continuous external heating,and the highest temperature in the treatment process is close to 400℃.When the oil content of oily sludge is 60g/kg,80g/kg and 100g/kg,the heating plate will be closed after the oily sludge is ignited successfully,and the smoldering front can advance self-sustainably.The maximum temperature in the smoldering process is around 500℃.Fourier transform infrared spectrum analysis was performed on the oil sludge samples before and after treatment,and no wave peak existed in 2750cm^-1-3000cm^-1section of the samples after smoldering treatment.The smoldering treatment effect was very obvious.Conclusion:In practical engineering applications,for oily sludge with oil content less than 40g/kg,continuous heating can be used to stimulate smoldering reaction to promote further treatment of organic pollutants in sludge;For oily sludge with oil content greater than 60g/kg,smoldering reaction treatment effect is obvious,which can be self-sustaining after ignition.4.Programming calculation of reaction equilibrium process of acid gas combustion furnace.In order to deal with a large amount of tail gas produced by smoldering treatment of oily sludge in practical engineering application,a matlab program is proposed to realize automatic calculation of reaction balance process of acid gas combustion furnace in sulfur recovery unit,and calculate reaction balance process of acid gas combustion furnace.