A MEASURE OF DRYING THE BAMBOO POWDER IN THE PROCESS OF MANUFACTURE OF BAMBOO PLYWOOD IN VIETNAM

HỘI NGHỊ KHCN TỒN QUỐC VỀ CƠ KHÍ - ĐỘNG LỰC NĂM 2017 Ngày 14 tháng 10 năm 2017 Trường ĐH Bách Khoa – ĐHQG TP HCM A MEASURE OF DRYING THE BAMBOO POWDER IN THE PROCESS OF MANUFACTURE OF BAMBOO PLYWOOD IN VIETNAM Le Khanh Dien1, Tran Van Hung1, Vo Tuyen2, Nguyen Tan Hung2 Nguyen Thanh Nam2, Nguyen Huy Bich3 University of Technology, VNU-HCM, Vietnam National Key Lab of Digital Control and System Engineering, HCMUT, VNU-HCM, Vietnam Ho Chi Minh City Nong Lam University, Vietnam ABTRACT: In the process of production of the bamboo tree products; the bamboo powder is the principal material in a multiple bamboo products: chopstick, bamboo art plywood, absorbent of sweat mat… However, this kind of powder has a huge absorbing characteristic of water even mist in the wet climate therefore the process of eliminating of water in bamboo powder is always requisite in order to keep in good condition The aim of the paper is to represent a design of a typical drying machine of bamboo tree powder that could be suitable to the domestic technology, salvage an unlimited natural energy in Vietnam in order to save the energy and eliminating the pollution for the country The research could propose a measure of saving energy for all kind of drying processes in the future for domestic industry Keywords: drying bamboo powder, natural energy, renewable energy, eliminating the pollution Introduction Bamboo is very popular in a large area in South East of Asia, especially in Vietnam This evergreen tree is considered as natural fence that is unable to cross Bamboo is also a very raw material for wattle, canvas, basket, seat, chopsticks, village house frame and even boats… This paper represents a measure of drying bamboo powder with recommended productivity of the designed machine is 100 kg/h a Bamboo tree Process of grinding trifling bamboo to powder The following figures represent briefly the process of the process of grinding trifling bamboo that were performed in CAD-CAM workshop of the 2National Key Lab of Digital Control and System Engineering (DCSELab), University of Technology, VNU-HCMC, Vietnam b After harvesting Trang 255 HỘI NGHỊ KHCN TỒN QUỐC VỀ CƠ KHÍ - ĐỘNG LỰC NĂM 2017 Ngày 14 tháng 10 năm 2017 Trường ĐH Bách Khoa – ĐHQG TP HCM c Trivial residue bamboo grinding machine d Bamboo powder Figure Process of production of bamboo powder Design a typical drying bamboo powder machine 1- Motor, 2- Reduction gearbox, 3- Chain engagement, 4- Bearing, 5- Rotating bamboo powder tank, 6- Exhalation chamber silo, 7- Central heating, 8- Fan, 9- Motor and gearbox Figure A system of drying general powder The price of bamboo powder will increase by the consumption of energy in drying process and a system of drying will engender a lot of pollution when gas, liquid fuel or rigid carburant are in central heating except electrical energy However, the price of electrical power is so high in comparison with the very low value of bamboo powder In this study we recommend to use direct thermal solar receivers that can satisfy all the given conditions 3.1 Analyze and selection a suitable system of direct solar a) Photo of a typical dish/Sterling system There are many types of direct thermal solar receivers; each of them has its own Prod and Cond: - Circular disk has no concentric point, the heat cannot concentrated and the manufacture of circular disk is not practical (Figure 3a) - Parabolic circular disk has a focus but it is difficult to manufacture The focus is a point so it is difficult to dry continuously a big amount of bamboo powder - Parabolic troughs is selected because it has a focus line, practical and relatively easy to manufacture b) a 400-m2 dish system in Australia [1] Figure Parabolic circular disk has a focus Trang 256 HỘI NGHỊ KHCN TỒN QUỐC VỀ CƠ KHÍ - ĐỘNG LỰC NĂM 2017 Ngày 14 tháng 10 năm 2017 Trường ĐH Bách Khoa – ĐHQG TP HCM Parabolic trough is selected because its flexibility in manufacture, according to [8] the percentage of application of parabolic troughs solar system is in the majority in application (Figure 4) Figure Reason of application of parabolic trough solar system 3.2 Parameters of a parabolic troughs solar system Figure a) Mathematical parabola b) Schema of the designed drying system: axis of the system, 2: bamboo powder, 3: conveyor worm, 4: circular open trough absorber, 5: fixed frame 6: parabolic reflector Computing of heating in a drying powder bamboo Wherein m0: the output mass of bamboo powder after drying, 4.1 The necessary heat The quality of bamboo powder is not depended on the uniform and homogenous of the bamboo grain but it is depended on its dryness According to [1] the maximum moisture of wood in general is in the range of 25% to 35% and the fungi cannot grow in wood when the moisture content is less than 20% Hence the designed system has the duty to decrease the moisture or increase the dryness of bamboo powder from 5% to 15% The selected average value of 10% of moisture is accepted So the dryness 100 D= (mo - m1)  10%, mo m1: the input mass of bamboo powder drying, before With the given productivity of 100 kg/h, the output mass of bamboo powder after drying is 90kg and the mass of mixed water inside powder that is removed out of bamboo powder is 10 kg/h According to [7]: Specific heat capacity of water liquid (25 0C) c= 4.1813 J/g.K = 4.1813 KJ/kg.K Specific heat capacity water vapor (1000C) =2.080 J/g.K = 2.080 KJ/kg.K According to [9] the temperature at collector can be greater than 3000C Eliminating all the loss of reflection, diffusion, transferring the temperature of the powder inside the worm tube cans greater Trang 257 HỘI NGHỊ KHCN TOÀN QUỐC VỀ CƠ KHÍ - ĐỘNG LỰC NĂM 2017 Ngày 14 tháng 10 năm 2017 Trường ĐH Bách Khoa – ĐHQG TP HCM than 1100 The necessary heat for alteration of 10 kg of water inside bamboo powder to steam and evaporate out of powder The selected ambient temperature is 250C and the selected highest temperature when powder is out of the conveyor is 1100C W/m2 With the loss of parasitic energy and the coefficient lost heat is about 20%, the real solar heat is q=220x80%=176 W/m2 and the total area of the designed parabolic collector solar energy is A= Q/q=1000/176= 5.68 m2 Heat for alteration of 10 kg water from 25 to 1000 : 4.2 Design the parameters of parabolic trough reflector Q1 = m.C.t =10x 4.1813x (100-25)= 3135.975 kJ A parabolic trough solar system in Figure is selected to gain the area of 5.68 m2: Heat for alteration of 25 kg water at 1000 to steam at 1000: - The parameter reflector is made by a stainless steel sheet SUS304 with a dimension Q2 = m.C=10x2.080=20.8 kJ Heat for alteration of 10 kg water from 1000 to 1100: Q1 = m.C.t =10x 2.080 x (110-100)= 208 kJ Total necessary heat: Q= Q1 + Q2 + Q3=3364.775 kJ for 100 kg of initial bamboo powder per hour The total heat had to be received per second or the needed heat power Q=3364.775/3600= 0.93 kW For security we selected the total heat power that the parabolic trough have to provide to the bamboo powder is Q=1 kW According to [9] and [10] the direct energy on of 0.5x3000x2000 Thus the width of the sheet 0.5 mm and the area of the stainless steel reflector is 2000x3000=6 m2, bigger than the demanded area of 5.68 m2 The axial length is m and the parabolic circumference arc is m that allows the length of circular absorber trough which hold the conveyor worm is stable with roller bearings at ends The sheet is bended and assembled its back to a composite frame of 20 mm width that is considered as thermal isolator -The focus distance OF is f = 0.5 mm, the equation of the parabola in Cartesian coordinate system is very simple: surface of the earth at a rate of about q=220 Figure Mathematical parabola diagram, focus distance f =OF=0.5 m 4.3 Design the parameters of worm conveyor Trang 258 - The conveyor worm A with the diameter of 250 which is adjusted to be coaxial with the HỘI NGHỊ KHCN TOÀN QUỐC VỀ CƠ KHÍ - ĐỘNG LỰC NĂM 2017 Ngày 14 tháng 10 năm 2017 Trường ĐH Bách Khoa – ĐHQG TP HCM focus line (point F in Figure 6) of the parabolic reflector is assembled to the center line of the open top circular absorbers trough B via a couple of end flanges roller bearing C in the Figure Selected length of trough and worm conveyor is 2000 mm (a bearing at a middle of the conveyor worm is no need), selected worm pitch is 250 mm hence there are about spiral pitches along the worm Figure Structure of conveyor bamboo powder absorber: a: Worm shaft b.Trough (solar receiver that is painted in black color outside) b End flange seft alignment roller bearing The parabolic reflector and the absorber are fixed each other and can rotate around a hint (F) 4.4 Orienting the axis of solar system to the Sun The Sun, the focus F and the vertex O of the parabolic solar system are always keep in a slightly straight line by the rotation motion of shaft F of the system The angular velocity of the system is equal to the one of the Earth That means: =2 radians/24 h= 2/(24x3600) 7.272e-5=0.00007272 rad/s rad/s= Or the rotating demanded angle of the system per minute = 0.1250 = 0.75’ This angle too small so we decided that it can be adjust time by time by hand in such a way that the shadow of the absorber F is at the vertex O of the reflector With the suitable direction of parabola axis, line rays from the Sun are considered from infinite and are parallel to the axis and reflex to the center of focus line or the absorber trough ACKNOWLEDGMENT This research is supported by DCSELAB and funded by Vietnam National University (Figure 7) The worm A is co-axis of trough B is activated by a motor to transport the bamboo powder in the absorber open top tube All these above components are fixed together and with the parabolic trough All the system can be adjusted by hand to direct the parabola axis to the Sun The support is nailed to the earth and bears the system via the bearing A Conclusion The design of drying bamboo powder machine by direct solar energy is a suitable measure of drying powder that is practical and saving energy The design almost achieved and ready to be manufactured We hope that the designed will save energy and sustainable in the protection of environment The ability of manufacture is enabling and in the near future the automatic orientation to the Sun installation will be included to ensure the better performance of the system HoChiMinh City (VNU-HCM) under grant number GEN 2016.48.02.06 Trang 259 HỘI NGHỊ KHCN TỒN QUỐC VỀ CƠ KHÍ - ĐỘNG LỰC NĂM 2017 Ngày 14 tháng 10 năm 2017 Trường ĐH Bách Khoa – ĐHQG TP HCM REFERENCES [1] Jack Robinson RRC,”Determining acceptable moisture content in plywood sheathing”, Professonal roofing, April 1996 [6] I S Sintali, G Egbo and H Dandakouta “Energy Equations for Computation of Parabolic-Trough Collector Efficiency Using Solar Position Coordinates”, American Journal of Engineering Research (AJER) eISSN: 2320-0847 p-ISSN : 2320-0936 Volume-3, Issue-10, pp-25-33 www.ajer.org [7] Thermal capacity, Creative Commons Attribution-Share Alike 3.0 Unported http://creativecommons.org/licenses/bysa/3.0/ [1] “Direct Solar Energy”, Intergovernmental panel on climate Chanes, Contribution to Special Report Renewable Energy Sources (SRREN) [2] “Solar energy renewable & sustainable Energy”, Science & Technology, Stellenbosh University, Republic of South Africa [3] Dan Arvizu (USA) and Palani Balaya (Singapore/India) “Direct Solar Energy”, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA [8] Matthias Gunther, Michael Joemann, Simon Sambor “Parabolic trough technology”, Avanced CSP Technology, Enermena [4] S C Bhattacharya, S Kumar “Direct solar energy”, Renewable energy systems: direct solar energy- Direct Solar Energy [9] G.N Tiwari, Arvind Tiwari, Shyam “Handbook of energy solar theory, [5] Catalog No 787E, “Screw Conveyor Catalog & Engineering Manual” [10] “Solar energy”, National Energy Strategy, Executive Summary, 1991/1992 hand book and application”, Spinger Edition MỘT BIỆN PHÁP SẤY KHƠ BỘT TRE TRONG QUI TRÌNH CHẾ TẠO VÁN ÉP BẰNG TRE TẠI VIỆT NAM Tóm tắt Trong quy trình sản xuất sản phẩm từ nguyên liệu tre bột tre nguyên liệu chủ yếu cho nhiều loại sản phẩm tre đa dạng như: đũa tre, ván ép mỹ thuật làm tre, chiếu tre hút mồ hôi,… Tuy nhiên, loại bột lại có tính hút nước cao, hút sương mù thời tiết ẩm ướt Vì quy trình loại trừ nước bột tre ln ln vấn đề tiên để trì tình trạng khả dụng loại vật liệu Mục tiêu nghiên cứu trình bày cơng việc thiết kế chủng loại bột tre phù hợp với công nghệ nước, sử dụng nguồn lượng thiên nhiên vô tận Việt Nam nhằm tiết kiệm lượng tránh ô nhiễm cho môi trường Chúng hy vọng biện pháp tiết kiệm lượng tránh nhiễm nghiên cứu giúp tiết kiệm lượng cho loại máy sấy khác nước Từ khóa: sấy bột tre, lượng tự nhiên, lượng tái tạo, loại bỏ ô nhiễm Trang 260 ... system can be adjusted by hand to direct the parabola axis to the Sun The support is nailed to the earth and bears the system via the bearing A Conclusion The design of drying bamboo powder machine... hand in such a way that the shadow of the absorber F is at the vertex O of the reflector With the suitable direction of parabola axis, line rays from the Sun are considered from infinite and are... m1: the input mass of bamboo powder drying, before With the given productivity of 100 kg/h, the output mass of bamboo powder after drying is 90kg and the mass of mixed water inside powder that