Study On The Pressure Drop Performance Of A Tube-wrapped Fixed Bed Reactor

A fixed-bed reactor is a type of catalyst that adds catalytic particles inside the device to form a catalytic bed.When the fluid flows through the catalytic bed,it contacts the catalytic particles or reactants directly involved in the chemical reaction to achieve gas-solid phase or liquid-solid.The opposite device.The main feature of the fixed bed reactor is that the catalytic particles remain close to stillness during operation.In view of the current difficulties in the treatment of high-concentration organic waste gas,a waste gas treatment process is proposed,which can control the temperature in the reactor in real time and make full use of the reaction heat released during waste gas treatment.In order to meet the requirements of the core equipment in this process for large-flux heat exchange,a multi-stream heat transfer and the design concept of the coiled tube structure are used to propose a coiled tube fixed bed reactor.Energy loss occurs when the fluid in the fixed bed reactor flows through the catalytic bed.This energy loss can be intuitively reflected by the pressure drop of the fluid at the inlet and outlet.In order to prevent the continuous operation of the reactor from being stopped due to insufficient power during the flow process,the gas needs to be pressurized at the beginning of the entire process,and the gas pressurization process will inevitably consume part of the energy.The source needs to invest corresponding economic costs.The greater the pressure drop generated by the fluid flowing through the pipeline and the catalytic bed,the higher the corresponding economic cost.Therefore,before the process design,it is necessary to study the influencing factors of the pressure drop of the fixed-bed reactor and the corresponding relationship between them,and finally achieve the purpose of reducing the pressure drop of the fixed-bed reactor and evaluating the performance of the pressure drop of the entire fixed-bed reactor.For the pressure drop of the tube-side part,this paper uses the experimental measurement results and the spiral coil resistance calculation results to verify the calculation formula,and at the same time find a method to reduce the tube side pressure drop.For the shell-side pressure drop part,the pressure drop under the condition of the catalytic tube filled with catalytic particles outside the wound tube fixed bed reactor is simulated and experimentally studied.In terms of simulation,this paper uses the CFD-DEM method for research.In terms of experiments,this paper measures the pressure drop generated when the fluid flows through the catalytic bed by changing the fluid flow rate,catalytic particle size and shape.Comparing the experimental measurement results with the Ergun formula calculation results,it can also explain the rigor of the experiment while verifying the Eugen formula.This article analyzes from the following three aspects:(1)CFD-DEM coupling analysis is performed on the pressure drop of 5 groups of fixed bed reactors with different size and shape particles,and the simulation calculation results of each group are compared.First,compare the calculation results with the experimental results to verify the model.Then several groups of particles with different sizes and shapes are selected for simulation,and the data of each group is plotted to observe,and an effective means of reducing the pressure drop of the bed is obtained.Finally,a particle that can significantly reduce the pressure drop of the bed compared to the spherical particle is obtained.(2)The pressure drop of the fixed-bed reactor around the tube is studied from the two aspects of catalytic particle parameters and gas flow rate,and an effective method for suppressing the bed pressure drop is obtained through the experimental results.Four groups of catalyst particles with different parameters are used for comparative experiments.The shell-side pressure drop of the fixed-bed reactor with tube-heat exchange is measured at the same gas flow rate.The experimental results of each group are compared and analyzed.influences.In the range of 0.1m/s~2.0m/s,multiple sets of experiments are carried out,and the experiment is repeated to obtain the pressure drop curve of the gas flowing through the catalyst bed filled with different catalytic particles and the gas flow velocity.(3)The theoretical calculation results are compared with the experimental measurement results to verify the calculation formula of the bed drop of the wound tube reactor,which is used to predict the bed drop of the fixed bed reactor under other bed conditions.In this paper,a reactor with a tubular structure filled with catalytic particles in the shell side is used.Due to the great structural difference from the conventional catalytic particles filled in the tube,the practicality of the improved formula needs to be analyzed and verified.Comparing the calculation results of the improved Ergun formula with the experimental measurement results,the reliability of the formula is verified.