Aiming at the shortcomings of dynamic risk analysis in large gasification units, a method of dynamic Bayesian network based risk analysis of gasifier feed system was proposed. The fault tree model was established by using the relevant data of failure forms of each unit of gasifier feeding system, and the fault tree model was transformed into a Bayesian network model. The bayesian network model was optimized by K⁃2 algorithm, and the influence of common cause failure on the system was processed by β factor method. Considering the influence of maintenance factors on the failure rate of the system at each moment, the accuracy and feasibility of the proposed method were verified by using the Bayesian network analysis software GeNIe and Monte Carlo. The results show that the dynamic Bayesian network has the advantages of accurate dynamic risk analysis and the ability to identify the weak links in the gasifier feed system risk analysis. According to the analysis results, a reasonable reliability allocation strategy can be obtained.

In order to obtain the dynamic change law of reliability of redundant repairable system under the influence of common cause failure, a new algorithm combining improved GO method with dynamic bayesian network was proposed. Firstly, the GO diagram model was established according to the schematic diagram and flow chart of the system. Then, the GO model was converted into a DBN by using the conversion mapping rules of each operator and signal flow to the DBN. Finally, the model was solved by using DBN mature software and algorithms. After verification and comparison, it can be seen that this method is not only able to obtain the dynamic curve of system reliability and availability changing with time, but also to treat the influence of maintenance factors and common cause failures on the analysis results. In additional, that this method with the powerful ability of reverse reasoning, is able to obtain the weak links quickly and provide reference the fault diagnosis for the system

At present,the energy efficiency evaluation of centrifugal pump units in China is still in the exploratory stage.In order to evaluate the energy efficiency level of the equipment quickly and accurately,based on the MVC model of the .NET platform,this paper designs and develops an automated evaluation system. On the basis of establishing the mathematical model of energy efficiency evaluation of pump units,the parameters are collected and processed. The data is imported manually or by accessing the database，and the energy efficiency calculation is performed according to the standard using a simple and highly accurate formula. The system is applied to verify the example，and the operating condition of the equipment is compared with the economic operation discriminate table to judge the operation of the unit. The results show that the evaluation results calculated by the software are accurate.Without complicated manual calculation,the evaluation time can be shortened,the work efficiency can be improved，and it has certain application value for industrial production.

In order to solve the dynamic failure problem of pulverized coal pressurized conveying system, a reliability evaluation method based on dynamic bayesian network is proposed in this paper.Firstly, based on the analysis of the structure and function of the pulverized coal pressurized conveying system, the fault tree model is constructed, and the reliability analysis model of the pulverized coal pressurized conveying system is established according to the rules of the trans⁃formation from the fault tree model to the dynamic bayesian network.Then, by introducing maintenance factors and time series, using the two⁃way reasoning ability of dynamic bayesian network, the weak links and the dynamic variation law of reliability of the pulverized coal conveying system are determined.The results show that the method can effectively describe the dynamic characteristics of the pulverized coal pressurized conveying system, and the analysis results are more in line with the actual working conditions.

The energy consumption evaluation indexes of fan units and pipe network system are obtained by referring to national standards and setting up a subtarget set of energy consumption evaluation,AHP analytic hierarchy process was used to analyze and compare the factors affecting energy consumption, and EXCEL software was used to deal with them. The influence degree of each factor on energy consumption was obtained, namely the weight of each factor.Using fuzzy mathematics,combining with the weight of all the factors obtained,evaluate the energy consumption for fan unit and pipe network system.Verified by examples,the system is in excellent condition,and it is consistent with the actual situation.

Once hydrogen sulfide is leaked and diffused, the consequences are unimaginable. In order to master the law of hydrogen sulfide diffusion, the diffusion law of hydrogen sulfide under the influence of source strength, wind speed and source height was numerical simulated by MATLAB and VC++ software. The simulation results show that at night, when the source strength increases, the downwind direction diffusion range increases under the leakage source, the hydrogen sulfide mass concentration gradient increases in the diffusion area, and when the source height increases, the maximum width of the downwind direction diffusion area under the leakage source becomes narrower and the area becomes smaller. During the daytime, when the sunlight intensity is low and the wind speed is greater than or equal to 4 m/s, the downwind direction diffusion range of the leakage source decreases as the wind speed increases, and the hydrogen sulfide mass concentration gradient decreases in the diffusion area. Increasing the source height and wind speed is beneficial to reducing the mass concentration of hydrogen sulfide and the hazard. The research results can provide a basis for accident prevention and emergency rescue.

According to the analytic hierarchy process (AHP) and referring to the national standard, the evaluation index of the energy consumption of the centrifugal pump system and the evaluation system of the centrifugal pump system were established. By using the theory of fuzzy mathematics, a complete evaluation method was formed.Using Matlab to solve the matrix of the largest features to determine the weight of each factor.The threshold value of each factor was obtained by statistical method, and the fuzzy matrix of each factor was obtained.The evaluation of energy consumption of a centrifugal pump in a factory was carried out. The evaluation results showed that the pump efficiency was the main factor affecting the centrifugal pump system;the energy consumption grade of the centrifugal pump system was 2, and the overall operation of the system was reasonable; in the single factor evaluation, the energy efficiency level of transmission efficiency was 4, which indicated that the drive mechanism was not running properly and needed to be handled.Therefore, this method had an important guiding significance for the energysaving transformation of the centrifugal pump system.

In tertiary recovery process, there was a need of the static mixer promoting the polymer solution mixed with water to drive oil. Therefore, the mixing efficiency of the static mixer had an important influence on the efficiency of oil production. Based on that the mixing efficiency of the current commonly used static mixer was not high enough, a new type static mixer was developed. The flow characteristics of the fluid in the mixer were studied by the numerical simulation, and the simulation results were verified by the experiments and the performance of the mixer was measured. The result showed that the results of the simulation and experimental were in good agreement; the new type static mixer had the high mixing efficiency and mixing effect; the pressure drop of the static mixer met the requirement, and the best inlet rate was about 0.14 m/s

According to FCC（catalytic cracking）gasoline desulfurization, a set of test device was designed. The working principle of the experimental device and the selection of the key equipment were introduced in the article. It would effectively reduced the pulsation and solved the low metering accuracy of the pump, and the mixing time of the static mixer was too short and resulted in undermixing, and heat loss was too much and so on. From a longterm perspective, the design of desulfurization device provided a new way and making up for the deficiency of the existing desulfurization device.

The numerical simulation was used to study the vertical scour way of fluid in the heat pipe exchanger by using CFD software FLUENT, and the flow field parameters such as pressure drop, temperature were analyzed. The results show that fluid pressure drop in the vertical scour way was less than fluid pressure drop in the lateral scour way under the same situation. But the heat transfer effect was poorer. The fluid pressure drop was affected by tube spacing and length in the vertical scour way, and fluid pressure drop was proportional to the tube length. The vertical scour fluid heat transfer effect could be improved effectively when the longitudinal fins were added to the heat pipe, which made the temperature distribution in the flow field be more uniform.

Wind load is a random load that can lead to the vibration of the coke tower. In order to research the influence on the strength of the coke tower by wind, ABAQUS was used to conduct the dynamic analysis of the wind load and the response of the structure during loading and unloading. The results indicate that, with the effect of wind, the maximal nodal displacement appeared at the top of the tower, which is 0.79 mm|while the maximal stress locate at the node around the skirt, the maximum is 3.26 MPa. Both of the displacement and stress could not cause the failure of the structure. During the loading and unloading, the structure engendered vibration along the loading direction. The vibration frequency was 10 Hz. Under the effect of external loads, it could easily cause the resonance of the structure, which could cause damages to the structure. Therefore it must be taken into consideration during the process of design and operation.

Based on the Pairs-Erdogan crack growth model and with the application of the moment and a crack limit equation of state, the reliability of the steam floating machine under the circumstance of random variable basic parameters was discussed, and a steam-floating impeller crack growth reliability model was established. The reliability of impeller crack propagation life was deduced, which is basically the same with the results of Monte-Carlo simulation. The result shows that the method can give a more accurate forecast results and is suitable for application.