Abstarct: The junction between the tube and tube sheet Elam refinery heat recovery boilers, sulfur recovery unit was destroyed due to unknown and then again, this phenomenon has been repaired four times. This thesis is baxsed on this problem definition and the resulting thermal stresses and strains will locate the exact location of the solution is given. Segregation of impurity gases from the standpoint of safety, corrosion control, setting the standard combination of gas and liquid products to prevent catalyst poisoning plants receiving gas or liquid products, and finally limit the release of pollutants to the environment are required. Claus main reaction of hydrogen sulfide oxidation by air oxygen in the presence of a catalyst was a single stage reactor. The products of the reaction of elemental are sulfur and water. This reaction is assumed there are no impurities and interfering substances. Note that the percent conversion of sulfur temperature, usually 70% of the total reaction is completed at this stage. So other than a stage or multi-stage catalytic combustion is also required. Sulfur after combustion and catalytic processes in order to progress condensation reactions and the flow is separated. To absorb the heat generated by the furnace and liquid sulfur reaction, also enhance the efficiency, emissions resulted, after the reaction furnace enter waste heat boiler. Usually most of the new units with the Claus sulfur recovery, heat recovery exchanger, furnace reactions are combined in a tank. Exhaust gases from the furnace with the reaction temperature of about 840 ° C, the internal tube heat recovery exchanger is a shell and tube type heat through and produce only water vapor are At this stage 15% of the total sulfur is obtained. The heat exchanger that acted with medium pressure steam as a boiler significant and provides the unit Air blower propulsion has shell that made of carbon steel and has been operating temperature and pressure as 21.02 psia and 210°C. Two-inch carbon steel pipe placed inside the shell that holds the operating pressure and temperature 840°C and 31.1 psia. Tube exchanger outlet temperature is 240°C in operational condition. Due to the temperatures, the distribution of sulfur in the reaction furnace chamber of the form S_ (1-2) to S_ (3-8) will become. Isolated sulfur in end of WHB driven as liquid in sulfur tank. To prevent excessive warming WHB tubes due to its low thickness, 2 -inch inlet pipe using ceramic rings are protected against heat. Generally, when you start to increase and decrease the temperature of the furnace, cracked rings and thereby causing the temperature of the hot gases over the mouth of the tube and its sulfide, which eventually led to the destruction of damaged and leaking pipes Power inner tubes, so you should install this as well as throat and cover the whole screen by refractory cement pipe is very accurate. This thesis examines the stresses and strains obtained from the high temperature of the inlet gas heat recovery boiler on the tube sheet, tube, between the tube and tube sheet welding has been. The refinery reported that Elam is getting accurate information modeling is done entirely baxsed on reality. Change the length of the tube and tube sheet is one of the most important results of this thesis because the main cause of degradation during the expansion of the high temperature gas-inlet tube and tube sheet of a heat recovery boiler. The modeling is done in two-dimensional phenomenon of boiling water on the outer wall of the tube, and three - dimensional to obtain thermal stresses and strains and also the length change is. Two-dimensional modeling of previous research and the results are less accurate. Three-dimensional modeling of two-dimensional model is much more accurate response. Given the current situation, these results correspond well with the experimental results. Maximum force in the connection between tube and tube sheet welding seen between them is destroyed.