The Analysis And Research Of Steam System Insulation Reformation In Refinery

In this dissertation,the performance and characteristics of commonly used thermal insulation material and heat preservation structure are compared and analyzed.What’s more,the difference between the technical standard of thermal insulation modification and the engineering practice is analyzed.A reconstruction scheme is proposed according to the actual requirement of enterprise,and the new suggestion to the technical standards of thermal insulation recommendations is given.The main work of this dissertation are as following.1.Analyze the general thermal insulation situation of existing steam pipe network,and investigate the weak links and existing problems to provide the technical support of updating the thermal insulation decision.For low pressure steam pipeline,the prominent problem is that the heat loses too much in the pipeline joint position,and the sinking of thermal insulation material forms of a flow channel at the bottom of the steam pipeline which causes excessive heat loss.According to the problems of too much joint,non-strict and easy to fall off,for the 1.0 MPa pipeline of several levels rock wool insulation shell,to satisfy the heat preservation performance requirements,comprehensive economy and construction,several layers of rock wool insulation tube shell structure through the joint position of stagger arrangement are adopted to furtherly reduce the steam heat loss;For the 3.5 MPa steam pipeline,many times of updating still have not solve the problem of heat loss exceeding the standard,so the combination of the inner layer of composite silicate aluminum roll and the outer layer of shell foam asbestos are used.The inner layer reduces the opportunity to form heat flow path at the bottom of the pipe,and the outer layer is arranged in a staggered arrangement of the rock wool insulation shell to further reduce the heat loss of the steam.2.By comparing the thermal conductivity,mechanical properties and price of the several commonly used thermal insulation materials,select the most cost-effective insulation materials.The performance of the commonly used insulation materials was studied,and the characteristics and adaptability of the insulation materials used in the refining enterprises were also analyzed.According to the analysis,the decision can be made that in refining the thermal insulation steam system,three kinds of material(shell foam asbestos,acid aluminum,and microporous calcium silicate)should be used.3.Through the analysis of the data,the rationality of setting the target value of the insulation is analyzed.Through the inspection of the heat preservation situation,the actual data are obtained.After the comparison,the target value of the insulation transformation is put forward.In the case of the insulation acceptance criteria,if the heat loss standard recommended by GB /T4272-2008 is used to carry out the transformation effect analysis,transformation of the economy will be greatly reduced,which deviates from the actual situation and will mislead decision-making;if directly use the GB/T4272-2008 recommended heat loss standards for project acceptance,it will make the construction side easily meet the overall quality which reduces the construction quality.To the enterprise,this will cause greater energy losses and waste of funds.Therefore,this dissertation puts forward that uses the lowest heat loss of the actual measured steam pipeline insulation in many years(the value in line with national standards and greatly lower than the national standard allowed maximum heat loss value)as the calculated standard value in transformation program effect analysis,but also as a construction acceptance criteria.4.By analyzing the encountered problems in insulation construction process,targeted solutions are put forward.The construction quality assessment results are assessed:(1)master project in line with the requirements of the specification;(2)more than 80% of the points in the general project spot checks within the deviation range specified in the specification.In the national standard,it is also a random sampling from each batch of arrival,random sampling has its reasonable side,but there are loopholes,which cannot rule out the situation of shoddy.Due to the use of spot checks,the drawback lies in the existence of contingency,and the acceptance results depends on the situation of the spot.On one hand,it cannot truly reflect the true quality of the insulation situation,and on the other hand,to the construction side or material suppliers,it provides a chance to make fool,resulting in that the final insulation effect is bad and difficult to determine the responsibility.In order to solve this problem,the material supplier should provide samples to do the application effect test,and after passing the test,they should supply the products quite as the sample;the construction standards should be higher than the national standard implementation;combine the technology of infrared temperature point monitoring and thermal imaging aids for acceptance check,and by this way to solve the exciting problems in the three links of material,construction,and acceptance check.5.By comparing the transformation effect and project,verify the rationale for the development of the transformation program and the validity of the reference standard.The reliability and achievability of the transformation target value are verified by the comparison of the heat loss data,the heat loss data before the transformation,the maximum heat loss and the change of the target value.It also verified that in the three links of material,construction,and acceptance check,taking more strict measurement and higher standard than the national standards is very effective.In other similar thermal insulation projects,this has a strong guidance and promotion significance,and it is conducive to the enterprise energy saving.