Unit spray water technology modification <1> The water spray point selection takes into account that the actual outlet temperature of the high pressure cylinder (% section) is lower than the design temperature (about 95) during normal operation, and it is difficult to open the hole in the high pressure cylinder, and due to gas pressure It is already very high. The saturated water vapor pressure is very small, and the water spray effect is not obvious in the first few stages. Therefore, this modification does not consider spraying water into the high pressure cylinder. According to the requirements of the transformation technology agreement, the outlet temperature of each section after spraying is lower than 85. For this reason, there are 8 water spray points in the low and medium pressure cylinders of the unit, as shown. Water spray technology implementation related parameters project low pressure cylinder (segment) medium pressure cylinder (segment) medium pressure cylinder (segment) 12 grade 23 grade 12 grade 23 grade 45 grade 56 grade water spray point number / 21 spray pressure / MPa2.53.5 Water spray / (m3h-1) 0.6520.6021.0010.9011.0510.951 Heat balance calculation In order to ensure that the compressor outlet temperature does not exceed 85, the water changes from liquid phase to gas phase, the heat absorption of water is equal to the heat release of cracking gas, using Germany The MDVT software developed by MDVT calculates the amount of water sprayed and the pressure between the stages and the stages as shown. The MDVT software calculation program makes the following assumptions for calculating the water spray amount: a. The latent heat of vaporization of the sprayed water is used to reduce the temperature of the cracked gas; b. The relative humidity of the cracked gas is 0. The actual amount of water sprayed per nozzle is determined by the nozzle diameter and the pressure difference between the nozzle front pressure and the gas. The water source requires a total injection volume of about 6.4 m3/h, the pressure requirement after the regulating valve is not less than 3.5 MPa, and the water temperature is 3060. The water source is the softened water after the desalination treatment of the boiler water supply or the turbine condensate, according to GB15762001 (industrial boiler water quality standard) There is no solid matter, oil, dirt and other impurities in the water. The specific indicators are shown in the figure. The nozzle is one of the most important components in the implementation of water spray technology, which directly affects the operating efficiency and working capacity of the modified compressor unit. According to the water spray scheme, and taking into account the convenience of future maintenance and spare parts replacement, the 1/2SB-TC1.1 and 1/2SB-TC1.33 nozzles produced by SprayingSystems of the United States were selected. The parameters are shown in the figure. At the same time, Y-type tungsten carbide was selected as the material of the nozzle to prolong its service life (the service life can be up to 23 years under the pressure difference of 3.5 MPa), and the unit is guaranteed to have no problem during one inspection period. Nozzle parameter item nozzle type 1/2SB-TC1.11/2SB-TC1.33 differential pressure / MPa2.0 flow / (m3h-1) 0.701.00 atomized droplet average diameter / m < 120 orifice diameter / mm3. 274.09 Core material Y-type tungsten carbide structure scheme design Because the low-pressure cylinder and medium-pressure cylinder block are thick (about 70mm), and the standard nozzle size is small (length 63.6mm), the nozzle needs to be modified. In order to meet the requirements of sealing, installation, maintenance, inspection and replacement, etc., the type of the nozzle body is lengthened and welded to the flange is determined. The schematic diagram of the installation structure is as shown. Nozzle installation structure diagram Selection of fixing seat material The original design of low pressure cylinder and medium pressure cylinder material is ASTM-216CrWCB. It is a heat-resistant weldable carbon cast steel with chemical composition close to domestic cast steel ZG275-485H. ZG275-485H has certain strength, good plasticity, toughness, good welding performance and working temperature of 400450. Therefore, ZG275-485H is used as the material of the fixed seat. The strength of the cylinder after opening the cylinder will have some influence on the strength, but because the cylinder is thicker (more than 60┨), the diameter of the opening is only 40mm; according to GB1506 (steel pressure vessel), when the shell When the nominal thickness is greater than 12mm, the nominal diameter of the connecting pipe is less than or equal to 80mm, no additional reinforcement measures can be taken, and since the fixing seat is welded on the casing, it plays a certain reinforcing role, so the strength of the cylinder after opening It is safe. Comparison of compressor oil injection and water spray <2> It can be seen that, compared with the oil injection cooling technology, the water spray technology greatly reduces the outlet temperature of the first three stages of the cracking gas compressor unit during normal operation. The effect of water spray on the inter-segment cooler is due to the continuous spray of water to the outlet cracking gas of each section being saturated, resulting in an increase in the amount of water between the sections. After spraying water, the inlet and outlet temperatures, heat load and condensation (hydrocarbons, water) and other parameters of the first three sections of the intercooler (a section of aftercooler, two stage aftercooler, and three stage aftercooler) Variety. Although the water spray reduces the outlet temperature of the compressor and reduces the cooling load of the heat exchanger, the amount of condensation of the liquid is increased, so that the heat exchanger must conduct the increased heat of condensation, so the cooler of the first 3 stages must be Cooling capacity is calculated. It can be seen that the cooler load between the sections after the water spray reform is smaller than that before the reform, indicating that the cooler between the sections after the water spray can meet the heat transfer requirements. Heat exchanger parameter item after a section of the cooler after the second stage of the cooler after the third stage after the cooler water spray after the inlet temperature / 84.5584.6184.25 water spray after the exit temperature / 35.7835.0535.00 heat load / kW original design 7995.95325.95131.0 actual operation before the transformation 9451.46374.57036.3 After the water spray modification 8208.96099.76212.54.3 The effect on the inter-segment separator after water spray is due to the lack of the original data parameters of the inter-segment separator, so the upper limit of the separation capacity of the separator cannot be determined, but because it is separated under the original system flow rate The working condition of the device is very good, so as long as the liquid flow rate after the water spray does not exceed the upper limit of the liquid flow rate before the water spray, the system can work normally. Therefore, it is possible to replace the amount of the original washing oil with the amount of water spray without having to calculate the total amount of liquid. It can be seen that the amount of water sprayed in each section does not exceed the upper limit of the amount of oil injected into the original system, that is, the total amount of liquid does not exceed the upper limit of the capacity of the separator, so it can be considered that the separator has sufficient capacity to spray the water. Separation, that is to say, the water spray modification has no major influence on the separator, and the original separator can be used continuously. Water spray volume and injection washing oil volume after the project transformation water injection volume / (kgh-1) original washing oil injection volume / (kgh-1) low pressure cylinder (section) 25005794 medium pressure cylinder (section) 19005470 medium pressure cylinder (section Problems and suggestions in 200026365 Although the outlet temperature of the first 3 stages of the compressor is less than 85 after the water injection reform, the polymerization scale in the cracking gas compressor unit is effectively suppressed, but occasionally a small amount of coking is present, and the preliminary analysis is water spray. Water quality is not up to the requirements, but also needs to be traced. It is recommended that the characteristics of the compressor cooling medium be fully considered.
our dished heads are used in a variety of applications and industries such as storage tanks, pressure vessels, road tank, food processing operations, chemical plants ,Nuclear operation, Oil Refining, Architectural feature, power generation.
Due to our forming experience and equipment, we can spin or press the first part of the process of forming your products, It depend on the thickness and material performance,
Our main products are 2:1 SE dished heads, Torispherical heads, Cones,Hemispherical Heads etc
Choosing the right type is the key decision for each customer and one for which our experience team to happy to give advice, simple speaking, the torispherical heads, the less ressure it can withstand, Conversely, the deeper dished heads, for example Elliptical heads, hemispherical, the greater pressure it can take.
Our in house-capability to form dished heads by cold press brings major benefits to our customers and sets us apart from others dished heads manufactures
For carbon steel dished heads, we can forming this dished heads from 76-9000mm in diameter and below 250mm in thickness
The general forming process as the below sketches
Technical Delivery Condition
2,Enquiry/order required information
We can give our clients once they gave us the below information
But if clients tolerance is higher than below Hokkai standards, it shall be provided to Hokkai prior to offer or ordering.
Stainless Steel Hemispherical Heads Stainless Steel Hemispherical Heads,SS Hemispherical Dishend Head,Hemispherical Head,Stainless Steel Hemispherical Elliptical Head YIXING HOKKAI HEAD PLATE CO.,LTD , http://www.hokkaidishedend.com
1,Our material (hot Rolled Unalloyed structural steel, high and low temperature steel, High Alloy steel)
We have no carbon steel plates in our stock and most of plates are from Chinese steel market or mill. Meanwhile As Japanese owed company, We can also source the plates from Japanese ex-mill if end user can`t accept ex-chinese mill.
Basically the delivery time shall be below 20days for dished heads if plates are from steel market. and Max plates width from them is below 2200mm. it means that the seamless dished heads diameter shall be below about 1800mm.
The max width CS plates that Chinese mill can do is below 4700mm,and dished heads can be seamless below 3800mm in diameter.
