Your Project: Typical data: Reactor dimensions: Diameter: 9000 mm, Height cylinder: 10000 mm (incl. skirt) Height cone: 9800 mm Steel structure dimensions: Height: 14400 mm, Base: 7700 mm x 6000 mm Penthouse dimensions: Height: 6200 mm, Base: 7800 mm x 4800 mm Weight: Ca. 70 tons Design conditions reactor: Pressure: -280…-300 mm H2O = 3 kN/m² Operation temperature: max. 250 °C Possible slagging weight of lime: ca. 40 tons Overall height of global structure: ca. 35000 mm Design of Complete reactor structure The total reactor-design consists of following parts: 1.Reactor shell structure 2.Reactor-roof with integrated spiral casing 3.Penthouse and platform on top of Reactor-structure 4.Reactor support skirt design 5.Reactor supporting steel structure It was necessary to take design decisions in an early stage of the project; so we decided to start the design on different items simultaneously and models were made of the different parts, using approximate boundary conditions and loading assumptions. Because the actual structure acts as an integrated entity, the different parts were assembled one for a crosscheck calculation using the ESA-Prima Win option to load (sub) projects into an existing project: it is possible to "assemble" the different building parts, and simulate the complete design (wind transfer from penthouse to reactor, different support-stiffness of reactor-support due to asymmetrical steel structure, combination of wind load and pressure in reactor …) 1. Reactor shell structure For design of this structure use of both global and local axis systems was made to define loading (wind loading according to global axes, pressure in reactor according to local axes of 2D elements…) For evaluating results of calculation (stresses in 2D macros), different output calculation facilities were used: stress SigmaE for interpretation of stress concentrations, stresses SigmX, Sigm Y to make distinction between longitudinal and circumferential stresses in reactor, used to investigate buckling of reactor (comparison with analytically calculated buckling stresses). Behaviour of reactor in corroded conditions was simulated by graphically selecting elements (considered as corroded) and reducing wall thickness and recalculate structure. Behaviour of structure at higher temperatures was done reducing E-modulus in calculation model. 2.Reactor-roof with integrated spiral casing To analyse the reactor roof and spiral case as a "plate-stiffened structure" we used the powerful possibility to combine 1D and 2D elements in 1 design: ribs on plates were used to model stiffeners on plates, using the option of eccentricity to make the most economical design possible. To evaluate the reinforcing influence of the spiral case on the flat reactor-roof, an model of the spiral case was used. Limitations were put on the deformation of the spiral case where the Atomiser is mounted. To evaluate the deformations of the roof +& spiral case in the workshop (support on 2 beams), modifications to the existing FEM model were made. 3. Reactor skirt design We evaluated the rigidity of the design and the stress concentration (specifically the stress pattern) near the support points of the reactor.( using the nodal mesh refinement option in these nodes) 4. Penthouse and Support structure The structures were designed using EC3. The complete model was used for the cross-check calculation, using actual force transfers in the reactor and penthouse-supports. The many possible load cases (wind in x, y direction, pressure in reactor, lime deposit in reactor cone, monorail loading of penthouse, loading of platforms of penthouse and support structure, insulation weight) this resulted in 596 EC3-combinations! In 1 of the reactors it was not possible to use bracings; a 2nd order calculation was done, to get reliable info on sway/nonsway conditions. 5. Seghers Rotary Atomiser Lime-milk is sprayed in the reactor using a distributor-plate turning at ca. 12000 rev/min. A critical design parameters of the axle is the "critical speed" (max. speed is limited by centrifugal forces). A simplified method of analysing this critical speed was done using a 1D-analysis of the axle this means evaluating deformations in the magnitude-order of microns! It is fascinating how in one global design (Reactor with Atomiser) 2 totally different mechanical structures (Reactor structure 100 tons, with cm displacements and Atomiser with axle 15 kg, with micron-displacements) are met. Since however both structures behave according to the same laws of mechanics and the resulting mathematical analysis, the same design software could be used! Extension of existing stairwell tower To access the roof & penthouses, the existing stairwell had to be extended. (18600 mm to 29240 mm) and one of the stairwell towers was loaded by the 2nd outlet fluegas-channel of the reactor (weight: 9 tons). To design the necessary reinforcements to the structure as well as keep reactions to foundation allowable an "as-built" model was used. Use of ESA-Prima Win 3D shell: For separate analysis of different parts of reactor 3D frame: For analysis of support structure and penthouse structure for simulation calculation of stairwell tower 3D shell + 3D frame: for cross-check calculations EC3 - check: For calculation of support structure and penthouse structure Non-Linearity: extra 2nd order calculation of the support structures 37 SCIA User Contest Catalog
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