Design of roller mechanism and conveyor in sulfur granulation systems

SCIENCE & TECHNOLOGY DEVELOPMENT, Vol 17, No.K2- 2014 Design of Roller mechanism and Conveyor in Sulfur granulation systems • Nguyen Thien Binh • Le Thanh Son • Nguyen Thanh Nam DCSELAB, University of Technology, VNU-HCM (Manuscript Received on December 11 th , 2013; Manuscript Revised September 04 th , 2014) ABSTRACTS: Roller mechanism and conveyor are solidify of sulfur in the supplying pile. important components in sulfur granulation Moreover, this paper shows the solution to system. This paper presents the method to design steel conveyor and filtering system design roller mechanism to apply two including with temperature sensor which goals: create a continuous pressure for a ensure the decreasing of temperature over regular granulation on steel conveyor. the length of steel bell. This will help the There are also granulation mechanism and granulation of sulfur with the right size and maintain temperature not to stuck and shape. Keywords: rotor-former, cooling steel bell, sulfur granulation system 1. INTRODUCTION The granulation system consists of two main The sulfur granulation system is one of the components: the granulation drum Roller most important components in sulfur processing. mechanism ) and the conveyor. The system includes many elements and 2. PRINCIPLES OF SULFUR components. This paper presents how to design a RANULATION PROCESS granulation drum in consideration of two factors: 2.1. Description of process stability of product and method to maintain Liquid of Sulfur from tank (1) is pumped constant temperature on the conveyor. through heating pipe to filter (3) before lead to Temperature sensorsare also integrated along granulation component (4). Pipe, filter and liquid with the length of steel-bell helping to control sulfur tank have to be heated by water stream (or temperature of product decreasing over a by heating resistors) to maintain the temperature predefined process. of the sulfur flow about 130 to 150 Celsius degrees. (Figure 1). Trang 14 TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 17, SOÁ K2- 2014 Figure 1. Principle of system working process.[2] Heat out from solidifying and cooling The rotor-former is equipped with a gas process is transferred by steel-bell to cooling exhaust. There is a cone pipe (15) above the water tank (9). This cooling process is done by rotor-former and steel bell assembled with a fan. spraying cool stream water at the bottom of the The granulated sulfur which is separated bell. It will return to the tank and continue to be from cooling bell will be carry to packing zone. pumped to the cooling water tank. In this period, (16) there is no contact between cooling water and 2.2. Property of sulfur granulated sulfur. After cooling process is finished, Property of sulfur granulated is used as input granulated sulfur is taken off from the steel bell factors to design the system. These are some by a steel knife (10). A standard separating agent properties of sulfur material: (Silicon: 97%, water and Tegopren: 3%) is Purity: ≥ 99,9% of total mass. sprayed on the steel bell forming a thin firm to Temperater input: 125-1350C ensure not to effect to the granulated sulfur (11). Pressure input: 3.5 bar g ± 0.1 bar g Cooling water (under the steel bell) fall to Density : 1800 kg/m3 130 0C collection tank (12) below the bell. Under the effect of gravity, water flow to tank (13) and Viscosity: 11 cp at 130 0C pumped back to cooling water tanks (14) to Humidity : ≤ 0.1% continue the cooling process. Shape: hemisphere Trang 15 SCIENCE & TECHNOLOGY DEVELOPMENT, Vol 17, No.K2- 2014 Size: 2 – 4 mm 2.3. System requirements Angle of respond: 28o The designed sulfur granulation system has Input temperature and pressure technical requirements that need to be responded. The technical requirements will be addressed so In these informations, the temperature, that the design for granulatingand roller output pressure of the materials are important conveyors can be the best respond. [1] parameters to calculate the granulator roller. Table 1. The technical requirements applied on the designed sulfur granulation system Input technical Parameters Unit requirements Productivity 800-1000 Kg/hour The purityof the raw materials ≥ 99.9 % wt Input temperature of raw material 125 – 135 0C stream The pressure of input raw material 3.5 ± 0.1 Bar stream (h=19,6m) Diameter of sulfurparticle 2 – 4 mm The level of granulation ≥ 98 % Product temperature after separation < 70 0C from the conveyor 3. DESIGN PROPOSAL droplet deposit, fall down through the holes and The design proposal isto maintain a constant evenly spread over the width of the conveyor (8). temperature at the inlet of the steel conveyor . During the falling, sulfur forms droplet on the Sulfur particles go thourgh the cooling steel conveyor surface, nondeformation and then conveyor in which temperature is controlled to solidified, finally forms sulfur particles in decrease gradually making uniform sulfur hemisphere shape. Rotoformer rotation speed is particles. synchronized with the speed the cold conveyor. Based on these requirements, the sulfur Sulfur granulation roller is an important part granulation roller includes: heating system, ingranulation process. This decides quality of cylindrical stator (6) and perforated shell particle including shape and size of sulfur (7)which turns concentric with the stator . Sulfur particles. Trang 16 TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 17, SOÁ K2- 2014 Figure 2. Principles and structure of rotor-former [2] To maintain a constant temperature while component has many considerable factors and the sulfur is forming, sulfur mixture is heated to most important thingsis the stiffness of spring around 125 - 135oC . This is the temperature at and gush-nozzle corecalculation. which the sulfur is maintained in the dough state Along with the pressure of chamber p, and can be the best well-formed. pressure from the spring with stiffness k directly If the temperature is lower, sulfur will affectsparticle diameter d and granulating gradually return solid form and choke at the capacity of the system Q. Chambercomponentis pipes and forming-holes. However, the higher designed so that the chamber pressure will push temperaturewill causes the mixture becomes extraction pressure spring andtherefore,willpush liquidand wastes energy. products go through each nozzle every time there To solve this problem, the sulfur granulation is a difference in presure at the time injection roller is designed with insulation-pipeline inside. holes on the roller matches with Heated oil is led into the roller by two pipe-lines, theconstantnozzles. heatingand maintaining the chamber temperature. At that time, the elastic force of the spring In additionto control the temperature of the equals to the differential pressure sum of the chamber, each 500 mm length of internal the system [3]: sulfur granulation roller, a pair of sensors is Flx = k. l = (Pextractionchamber– integrated in external case of the chamber . Pnozzle).Ahole Task of the roller chamber is to ensure a - liscompression of the spring, determined constantpressure on sulfur mixture. Two ports of by the limit internal size of the component (5-10 the roller also havesulfurpipelines to mm). thechamber.The sulfur pumped into the chamber - k is the stiffness of the spring. is the product of the previous mixing-component - Aholeis the area of the hole that can be that includes tanks and paddles. Chamber adjust the aperture of the hole-πr2 Trang 17 SCIENCE & TECHNOLOGY DEVELOPMENT, Vol 17, No.K2- 2014 Also, particle diameter can be calculated as - T0 is the temperature at the output of the follows : [1] making particle roller. Q.A - Cs is the specific heat of sulfur. D = Pnozzel - L is the length of the conveyor. So thatthe necessary stiffnessof the spring - q is the heattranfer out of the conveyor per holding thenozzles value is: meter. P.D.Pnozzel k = Q l Sothe necessary temperatureof cooling water for each meter of calculation conveyoris: In addition, the aperture size and shape of qn = q = (ton – tn).Cn the nozzles on the extraction holecanbe adjusted. (t0 – t1) This helps toincreasethe diversity of
tn = ton – q/Cn = ton – L sizeandshapeofparticleproducts. Basedon water temperatures that steadily 4 .THE CONVEYOR DESIGNING decreases per meter of conveyor and the normal Conveyor is located after the sulfur temperature of cooling water is15oC, we can granulation roller component. Steel conveyor calculate the pump capacityand the chiller in task is to maintain a decreasing steadily each specific work mode. temperature from the beginning to the end of the conveyor that makes the sulfur turns into solid 5. CONCLUSION This paper points out the need-to-solve- before packing. problems and design options apply to two To do this, the steel conveyor is designed important structures of the sulfur extraction many cooling spray nozzels with cold water in system are: the sulfur roller mechanism and the vertical and horizontal position.Cooling sprinkler steel conveyor. The sulfur roller mechanism system spraygushs by dispersal method, the cold performs two tasks: creates continuous and water particles are not in contact with conveyor constant pressure; creates constant temperature to at a constant area, they are sprayed on the bottom avoid congestion and solidified sulfur in the pipe- surface of the conveyor. This helps avoid lines. In addition, this paper also provides the warping sulfur particles when the temperature the designing solutions for the variable heat steel bottom of the conveyor is not uniform. [4] conveyor systemand theimpurities filter system The t1 = 70oC particle temperature with thermal sensors on the conveyor that decreasing necessary according to calculation ensures temperature will regularly reduce along requirement and heat processing with the lost the length and the width of the conveyor. The heat in each meter conveyor is : design parameters of the these COMPONENTS (t0 – t1).Cn q = can be input terminals for the other L Trang 18 TAÏP CHÍ PHAÙT TRIEÅN KH&CN, TAÄP 17, SOÁ K2- 2014 COMPONENTS, such as: material supplying and Control and System Engineering (DCSELAB), mixing system and insulation pipes. HCMUT, VNU-HCM. ACKNOWLEDGEMENT: This research was supported by National Key Laboratory of Digital Tính toán thi t k c ơ c u con l ăn t o h t và băng t i thép bi n nhi t trong dây chuy n s n xu t h t l ưu hu ỳnh • Nguy n Thiên Bình • Lê Thanh S ơn • Nguy n Thanh Nam DCSELAB, Tr ưng ð i h c Bách Khoa, ðHQG-HCM TÓM T T: Cơ c u con l ăn và b ăng t i thép là lc t p ch t. C m bi n nhi t ñ trên b ăng các thi t b quan tr ng trong dây chuy n ti thép ñ m b o cho nhi t ñ gi m ñ u sn xu t h t l ưu hu ỳnh trong công nghi p. trên chi u dài b ăng t i và ñng nhi t ñ Con l ăn t o h t ngoài nhi m v t o áp liên trên b ăng t i theo chi u r ng. ðiu này s tc ñ r i h t trên b ăng t i thép thông qua giúp cho h t l ưu hu ỳnh t o ra ph ng và gi cơ c u chi t còn c n ph i duy trì nhi t ñ ñúng kích th ưc hình d ng yêu c u. Ngoài không ñi ñ tránh ngh t và ñông ñc l ưu ra, bài báo c ũng ñ xu t các ph ươ ng án và hu ỳnh trong ñưng ng c p. Bài báo gi i ñu vào c n thi t cho h th ng này ho t thi u ph ươ ng án thi t k c n thi t cho ñng t t. băng t i thép bi n nhi t và h th ng l ưi T
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