Shandong heat exchanger cleaning (6) by chemical process calculation, the total heat transfer rate equation q = KS Δ TM calculates the heat transfer area s, determines the basic size of the heat exchanger, and selects the equipment specifications according to the series standards（ 7) Calculate the tube side and shell side (8) calculate the pressure drop of the fluid in the tube side and shell side of the primary equipment. If it exceeds the allowable range of the process, adjust the flow rate, and then determine the number of tube sides or baffle spacing, or select another heat exchanger to recalculate the pressure drop until the pressure drop meets the requirements. The above design process also involves a large number of formulas, the specific calculation formula can be referred to [1]. The heat transfer area s is preliminarily calculated, the basic size of the heat exchanger is determined, and the equipment specifications are selected according to the series of standards（ 7) Calculate the tube side and shell side (8) calculate the pressure drop of the fluid in the tube side and shell side of the primary equipment. If it exceeds the allowable range of the process, adjust the flow rate, clean the heat exchanger to determine the number of tube sides or baffle spacing, or select another heat exchanger to recalculate the pressure drop until the pressure drop meets the requirements. The above design process also involves a large number of formulas, the specific calculation formula can be referred to [1]. 1. Selection of heat exchanger: temperature change of two fluids: inlet temperature of hot fluid soybean oil is 133 ℃, outlet temperature is 40 ℃; The inlet temperature of cold fluid (circulating water) is 30 ℃, and the outlet temperature is 40 ℃. Because the temperature of the two fluids is different, the temperature of the tube bundle and the shell is also different, so their thermal expansion degree is also different. In tubular heat exchanger, the temperature of shell and tube bundle is different due to the difference of temperature between cold and hot fluids. Therefore, their thermal expansion is also different. If the temperature difference between the two fluids is large, the equipment may be deformed, even bent and broken due to stress, or the pipe may be loose from the tubesheet. Therefore, appropriate temperature difference compensation measures shall be adopted to eliminate or reduce the thermal stress. According to different methods of heat compensation, tube heat exchanger can be divided into the following main types: (1) fixed tube sheet. The so-called fixed tubesheet is a structural form in which the tubesheet at both ends and the shell are connected as a whole. Therefore, it has the advantages of simple structure and low cost, but it is difficult to clean the shell side. Therefore, the fluid in the shell side is required to be relatively clean and not easy to scale. When the temperature difference between the two fluids is large, thermal compensation should be considered. The fixed tubesheet heat exchanger with compensation ring (or expansion joint), that is, a compensation ring is welded on the appropriate part of the shell. When the shell and tube bundle expand differently, the compensation ring will change its elastic shape (stretching or compression) to adapt to the different thermal expansion of the shell and tube bundle. This method is suitable for the case where the temperature difference between two fluids is less than 120 ℃ and the shell side pressure is less than 60MPa. The choice of heat exchanger: two fluid temperature changes: hot fluid soybean oil inlet temperature 133 ℃, outlet temperature 40 ℃; The inlet temperature of cold fluid (circulating water) is 30 ℃, and the outlet temperature is 40 ℃. Because the temperature of the two fluids is different, the temperature of the tube bundle and the shell is also different, so their thermal expansion degree is also different. In tubular heat exchanger, the temperature of shell and tube bundle is different due to the different temperature of cold and hot fluids. Therefore, their thermal expansion is different from that of heat exchanger. If the temperature difference between the two fluids is large, the equipment may be deformed, even bent and broken due to stress, or the pipe may be loose from the tubesheet. Therefore, appropriate temperature difference compensation measures shall be adopted to eliminate or reduce the thermal stress. According to different methods of heat compensation, tube heat exchanger can be divided into the following main types: (1) fixed tube sheet. The so-called fixed tubesheet is a structural form in which the tubesheet at both ends and the shell are connected as a whole. Therefore, it has the advantages of simple structure and low cost, but it is difficult to clean the shell side. Therefore, the fluid in the shell side is required to be relatively clean and not easy to scale. When the temperature difference between the two fluids is large, thermal compensation should be considered. The fixed tubesheet heat exchanger with compensation ring (or expansion joint), that is, a compensation ring is welded on the appropriate part of the shell. When the shell and tube bundle expand differently, the compensation ring will undergo elastic deformation (tension or compression) to adapt to the different thermal expansion of the shell and tube bundle. This method is suitable for the case that the temperature difference of cleaning fluid between two heat exchangers is less than 120 ℃ and the shell side pressure is less than 60MPa.