Investigation of simulation and optimization for nitrogen gas generator using pressure swing adsorption

ed during adsorption. Therefore, diffusion and adsorption processes into micropore is easier. The best pressure of product is exactly one value less than feed pressure equal to pressure drop through a bed. 139 Figure 3. 69 Purity of product depend on pressure of product. Figure 3. 70 Purity of product depend on recovery rate of product. Figure 3.70 shows that purity of product increases when recovery rate of product decreases due to consumption of product line to purg for single fixed bed. Optimal results on experimental system at feed pressure of 5.5 bar, get product at pressure of 5.3 bar and recovery rate of product R = 0.35, product stream reache concentration ≥ 99.5% N2. The changing of parameters at optimum working conditions of equipment such as pressure, flow and concentration of product are shown in figures from Figure 3.71 to Figure 3.74 below: Figure 3.71 Pressure of bed, two beds alternating Figure 3.72 Pressure of other bed, two beds alternating. 140 Figure 3.73 Mass flow in/out of two beds Figure 3.74 Concentration of N2/O2 at outlet of two beds Figures 3.71 and 3.72 show rule of pressure according to time and height of two beds B1 and B2. Inflection points in graphs are opening/closing states of get product and pressure balance valves. Distribution of pressure according to height of bed is evident during adsorption and desorption processes, pressure drop through particle layers of bed is approximately 0.22 bar. Figure 3.73 shows rule of mass flow in/out of two beds or equipment according to time and which clearly are observed recovery rate of product (R) is difference between in/out mass flow; peak points are times of opening/closing the supply valve and get product is very stable. Figure 3.74 shows that concentration of N2 gas product is very stable according to time when equipment is operating at optimum conditions. From investigation results of simulation and experimental, they can be compared as Table 3.11 below: Table 3. 13 Comparing of simulation and experimental, optimize for two beds No Parameters Simulation 3.7.2.1/2 Experimental 3.7.2.3 Discussion Skarstrom (4 step) Berlin (6 step) 1 Rule of pressure in two beds Partial pressure of O2 in initial gas phase increases Total pressure initially increases during Total pressure increases initially during Simulation and experimental are similar in rule, but in experiment only 141 during pressurizatio n phase, then decreases time and height of bed during adsorption. Similar to desorption in porous solid phase, but according to two opposite directions pressurizatio n phase, then decreases according to time and height of bed during adsorption and desorption processes. But there is a rapid drop in pressure after adsorption due to sudden get product at low pressure and failure to maintain adsorption pressure. adsorption phase, then decreases according to time and height of bed during adsorption and desorption. But there are inflection points at time of opening product get valve and time of balancing two beds. The change is very stable after many cycles. measured total pressure. The essence is the same because when gas flow passes through adsorbent column, adsorbent only retains O2 until saturation. The concentration of O2 decreases gradually with height of and time. But difference in profile due to pressure drop during opening and closing get product and balance valves. The 6-step Berlin cycle has a smoother work path than Skarstrom due to optimized bed regeneration and product retrieval. 2 Optimal working feed pressure for two beds p, bar Feed pressure of adsorption process is 5 - 5.5 bar And purging pressure of desorption is 1.5 bar Adsorption pressure reduced from 5 bar to 3.5 bar due to get product at atmosphere pressure. Desorption pressure is 1.5 bar but prolonged Adsorption pressure of 5.5 bar, only 0.3 bar reduction in a short time when the valve is opened to get product but then return to the same. Simulation pressure differs from pressure of 4- step cycle by get product at atmosphere pressure; differs from 6-step cyclic pressure due to increased losses due to consumption of N2 gas used to purg 142 time. for bed by countercurrent purity of N2 stream, but simulation only optimal pressure of a bed is simulated, not get into account losses due to countercurrent purity of N2 stream. Berlin cycle experiment is more optimal than Skarstrom cycle due to add equilibrium step to save energy, but requires a larger optimum pressure due to purging loss of bed. 3 Pressure drop through particle layers Δp, bar 0.2 Through particle layer: ≈ 0.22 Through a bed: ≈ 1 Through particle layer: ≈ 0.22 Through a bed: ≈ 1 Pressure drop through a bed measured experimental is greater than pressure drop is determined through simulation because in simulation not taking into account pressure drops through sieve, filter supports of adsorbent layer, but only drop throug particle layer of adsorbent and 143 adsorption process. Contemporaneou s, pressure drop during Berlin cycle increases due to increased pressure, flow of inlet flow and through valves, fittings and pipes. 4 Adsorption time t, s 30 s 30 s 30 s Adsorption time of simulations and experimental of 4 and 6 steps are the same because productivity of bed is constant. But time of one cycle increases due to setting of additional steps to optimize for equipment. Simulation and 4 steps, there is no equilibrium step to shorten pressurization time and simulation, only gas flow velocity is calculated along axial direction, not taking into account radial dispersion and uniformity through section of bed period. In fact, diameter of 144 equipment is insignificantly small, radial velocity is also very small. 5 Concentrati on of N2 gas product 100% 93.5 % 99.6 % Concentration of N2 in 4-step cycle investigated products is lower than 6 steps and simulated because there is no phase purging for bed, so adsorption efficiency in next cycle is reduced because there is still O2 during previous cycle. 6 Product recovery, R R = 0.35 correspondin g to purging rate of column u = 0.1074 m/s; purging at pressure, ppurg = 1.5 bar R = 0.759 Do not purging and get product at atmosphere pressure R = 0.35 Correspondin g to purging bed at pressure p = from 5 bar to 1.5 bar Recovery rate of product is lower, but purity of product is higher Comment: simulation and optimization for N2 gas generator using pressure swing adsorption are consistent with built experimental system model. Experimental results with a single fixed bed and two beds show that above simulation results are reliable. Comparison experimental between Skarstrom (4 steps cycle) and Berlin (6 steps cycle) shows that 6-step cycle is optimized and will be selected for investigation and deployment to industrial scale-up because of concentration of products meet requirements. The above simulation results are very 145 reliable, can be used as a tool to research and transfer scale-up equipment to industry for different applications by calculation and simulation method. 3.7.3 Simulation and experimental comparision of a single fixed bed and two beds Investigate of simulation and experimental for two beds helps us observe changing rules of technological parameters and select optimal working mode of beds and equipment. In this study, to maximize adsorption efficiency of each bed in a cycle, it is necessary to have a stream of pure N2 to purg for bed. The purpose is to maximize amount of O2 absorbed in adsorbent due to its concentration difference compared to countercurrent purging flows, which will reduce the N2 gas recovery rate in product stream. This means to find a reasonable rate of regeneration current or in other words optimal diffusion coefficient as theory presented. This problem can be verified by a control technique on an experimental system. In addition to purging technique with countercurrent, it is also possible to use vacuum swing adsorption (VSA) or temperature swing adsorption (TSA), but in this study purging technique by countercurrent is the most suitable and cheapest because there is no need to invest in additional equipment. Figure 3.75 Comparing concentration of N2 and O2 at outputs between a single fixed bed and two bed 146 Investigate results comparing concentration changes of N2 and O2 at output of a single fixed bed and two beds in Figure 3.75 below show clearly its stability when scale-up from a single fixed bed to two or more beds. Figure 3.75 shows that more beds, output concentration is more stable, which shows that in all studies on separation of substances using pressure swing adsorption (PSA) wanted to produce stable at output requires at least two or more beds. 147 3.8 Scale-up industry for equipment and applications Similar to investigation results of simulation and experimental for a single fixed bed and two beds were presented. The N2 gas generator using pressure swing adsorption on a small capacity or pi-lot scale, it has productivity from 10 to 14 liters/min and concentration N2 ≥ 99.5% has been studied and submitted successfully. Simulation is the best way, fastest and most efficient method of transfer for equipment to industrial scale-up. The industrial scale-up transfer method includes: firstly, getting material analysis results from 3.1 and equipment design calculation results according to section 3.2, calculation and analysis of pressure drop as item 3.3, calculating velocity and diffusion coefficient as shown in section 3.5. The results of equipment sizes, kinetic parameters then enter these parameters into established models or software to simulate optimum working conditions of bed and equipment such as Section 3.7. Contemporaneous, investigating and optimizing for equipment experimentally according to steps setup in this thesis with approximate parameters determined in simulation before factory is put into supply for applications and production. There are two main methods of scale-up: method 1 as outlined above which is a basic scale-up method; method 2 is a method of multiplying number of beds by 2n by joining parallel similar beds. Method 1 can be applied on a small capacity scale, method 2 is applicable on larger capacity scales and has higher product quality stability requirements. Advantage of this method is to make use of results of thesis model and simulation. But disadvantage of method is that error increases with yield because model does not take into account diffusion in radial direction. Therefore, in order to scale-up large productivity it is necessary to take into account radial and axial diffusion coefficients, total diffusion coefficient is a vector quantity of those two components. In which, axial diffusion coefficient has more influence because axial speed is usually larger due to larger space. In addition, a larger-scale transfer method can be applied by coupling multiple beds in parallel, but more control systems and actuators are required to control and operation of the equipment. Concentration and 148 flow rate of product line can be more stable. Results of scale-up by calculation and simulation are presented in section 3.8.1 below. 3.8.1 Scale-up industry for equipment with different productivity For example, it is necessary to scale-up a N2 gas generator using PSA has capacity of 50 l/min, concentration of N2 ≥ 99.5% at standard conditions to supply N2 gas for hexamine transport in process of RDX production. Using results of analysis and calculation and input data into simulation software: column diameter Db = 0.160m; height of adsorption layer Hb = 0.92 and related calculated kinetic parameters. Equipment simulation by Matlab software, with simulation results of adsorption process at feed pressure of 5.5 bar as shown in figure 3.76. Figure 3.76 Simulation results of pi(z, t) adsorption process for a single fixed bed capacity 50 liters/min at feed pressure 5.5 bar Figure 3.77 and Figure 3.78 determine adsorption time of bed is 40 s at feed pressure 5.5 bar. Similarly, optimal desorption time can be determined by simulation as 40s, Figure 3.81. 149 Figure 3.77 Simulation result of pi(z, 60) according to height of bed at 60s Figure 3.78 Simulation result of pi(0.92, t) time at output of bed z = 0.92 m 150 Figure 3.79 Simulation result of pi(z, t) desorption process for a single fixed bed capacity 50 liters/min. Figure 3.80 Simulation result of pi(z, 60) according to height of bed at 60s. 151 Figure 3.81 Simulation result of pi(0.92, t) time at z = 0.92 m Similar experimental results have been built in this thesis, to convert to industrial scale-up, it is possible to apply equipment simulation and optimization method by Matlab software to determine optimum working pressure and time of equipment, and then continue to study the simulation by Presto software to observe movement in column, finally investigate on simulation and optimization by Aspen Adsorption software to find the appropriate rate of product recovery to achieve highest capacity and stable product concentration. Comprehensive simulation and optimization of equipment at different capacities, for each specific application, is shown in Table 3.14. Comment: As such, it is possible to simulate and optimize nitrogen gas generators at any capacity for each specific usage. In Vietnam, this equipment is essential for a small and medium scale production such as in manufacture of propellants and explosives, for storage of weapons such as rockets and especially in production and storage of fruits and foods such as rice. For example, typical application of this equipment is used in production of hexogen explosives (RDX). 152 Table 3. 14 Scale-up industry results for N2 gas generators by calculation and simulation No Capacity Para meter s Unit 14 L/min 25 L/min 50 L/min 100 L/min 1 Capacity Fp N.L/min 14 25 50 100 2 Diameter of bed Dc m 0.102 0.135 0.160 0.214 3 Total height of bed Hc m 0.838 0.916 1.240 1.457 4 Total volume of bed Vc m3 0.007 0.007 0.010 0.012 5 Mass of CMS- 240/unit m kg 7 12.5 25 50 6 Concentration N2 C % 99.5 99.5 99.5 99.5 7 Product recovery rate R (-) 0.44 0.44 0.44 0.44 8 Air feed flow Ff N.L/min 31.8 56.8 113.6 227.3 9 Optimal working pressure Pop bar 5 5.5 6 6.5 10 Maximum working pressure pmax bar 8 8 8 8 11 Pressurization time tp s 15 20 25 30 12 Adsorption and Desorption time tad s 30 35 40 45 13 Equilibrium time tcb s 5 5 5 5 14 Total time of adsorption cycle tt s 100 120 140 160 3.8.2 Application of N2 gas generators for production of RDX explosive Manufacturing process of cyclotrimethylenetrinitramine (RDX) explosives is a hazardous and dangerous process that requires absolute compliance with safety regulations in technological process and equipment operation, especially assurance 153 factors. In which, process of transporting hexamine by screw to reactors is a process that needs special attention because this material is very flammable, leading to danger to other processes, pay attention to avoid friction and environment. Transporting must minimize oxidants such as O2 gas. Currently, plant is using N2 gas as a fire prevention agent. According to the overseas design, N2 gas supply in form of high pressure bottles is shown in Figure 3.82 The drawback of this design that is very difficult to ensure active and continuous N2 gas supply, difficult to ensure continuity in production. Figure 3.82 N2 gas bottles supply for hexamine screw system Therefore, it is necessary to design and optimize the N2 gas supply system according to the plan of parallel installation of N2 gas generator to ensure production safety. An equipment installation diagram is proposed according to Figure 3.83. The N2 gas generator with following requirements: (according to the designing mission in Z195). Supply nitrogen gas to hecxamine inlet of 2 nitrators 1C201, 1C202: 154 + Flow: from 40 to 50 liters/minute (supply flow to each hecxamine inlet of 2 reactor 1C201, 1C202 from 20 to 25 liters/minute). + Pressure: 1.0 kG/cm2 - pressure of gas flow behind flow meter of a ball float type, sprayed at inlet of hecxamine feed. + Temperature: from 5 to 35oC + Quality: nitrogen gas content > 99 %. + Supply: continuous 24/24 h. Figure 3.83 Nitrogen gas generator was installed in addition to nitrogen supply system for hexamine feeder. 155 To meet these design requirements, one equipment that has been studied successfully scaled-up in Table 3.14 with capacity of 50 L/min N2 99.5% at standard conditions. This equipment is installed to supply N2 gas for hexamine feed system for RDX production line. The result is a great safety efficiency in production process, keeping quality of raw materials to avoid burning before entering reactor. In addition, its applications in production of RDXs, N2 gas produced by PSA equipment can also be used in many defense production lines such as chemical powder, pyrotechnic grinding processes, propellants, and weapons preservation, specials like rockets. In industry, it also can be used in heating treatment of parts to increase hardness of surface of part and is particularly widely used in plasma and laser cutting machines. Figure 3.84 N2 gas generator using PSA capacity 50 liters/min, N2 content ≥ 99.5% at standard conditions. Figure 3.84 shows a scale-up N2 gas generator for a number of applications in fire protection in several stages hexogen production technology and cooling laser cutter electrode. In addition, this equipment is also widely used in other industries such as producing and preserving food, especially rice [31]. Because nitrogen produced by this technology is cheap and non-toxic. It is used extensively in production, processing and preservation of foods to prevent oxidation, enzymes and react with harmful 156 microorganisms to prolong shelf life of food. For example, preserving fresh fruit for export is one of vital issues in production and processing of fruits. Comment: nitrogen gas is produced by a generator using pressure swing adsorption, it is widely used in manufacturing and storage industries at small to medium capacities. Therefore, simulation of N2 gas generator is not only of scientific but also has great practical significance, but in Vietnam, there is no group that researches the design and manufacture on an industrial scale-up. The potential of using this equipment for defense industry and food preservation is enormous. Especially, this equipment can supply nitrogen gas to ensure safety during production of production lines as propellants, explosives, weapons storage, controled air technology (CA) to food storage in floodplain areas, and drying technology in N2 gas environment for pharmaceuticals production. Contemporaneous, method can also apply for PSA cycle and other separating materials such as H2 purification, removed water separation in alcohol to prepare fuel and especially, production of ventilators ( O2 gas production) by PSA cycle and VPSA using Zeolite 4A material to support Covid-19 treatment in Vietnam. 157 CONCLUSSIONS * The main results of the thesis 1. The thesis has identified basic characteristics of carbon molecular sieve adsorbent CMS-240 what supplier does not provide such as bulk density, particle density, solid density, particle size distribution, porosity, specific surface, composition and structure of adsorbent by analysis and calculation methods available in Vietnam. The results show that the main component of the adsorbent is carbon, cylindrical particles, two-layer structure. They are fabricated by impregnation, extrution and drum coating and activation at very high velocity and strictly controlled conditions. There are a lot of macropores, mesopores and micropore uniformly, total porosity of the adsorbent is εt = 0.615, specific surface result is determined by calculation according to capacity of bed Sr = 1146 m2/g is quite reliable compared to the actual yield obtained; to has built a completely experimental system of N2 gas generator successfully as pilot scale, with high level of automation to study purposes, It has productivity from 10 L/min to 14 L/min N2 gas ≥ 99.5% at standard conditions. It is installed a full range of measuring insttruments (pressure, temperature, flow and concentration sensors) with high accuracy (pressure sensors are installed according to height of bed, mass flow I/O flow sensor and S7-1200 PLC control system, real-time accurate data acquisition monitoring and monitoring (SCADA) can import and export data easy experiments; to calculated, analyzed and measured of pressure drop through particle layer of bed, depending on velocity of gas flow through section of bed and diffusion process in the adsorption and desorption processes. In fact, the pressure drop through particle layer is not linearly dependent on velocity in the adsorption and desorption processes due to pore attraction. 2. The thesis has established a mathematical model describing rules of adsorption and desorption processes in a single fixed bed according to partial pressure of oxygen depending on time and height of bed with initial condition and boundary conditions as working mode of bed and equipment according to pressure 158 swing adsorption (PSA); to have calculated to determine a set of model parameters to program and simulate the established mathematical model; to has determined the important model parameters by calculation such as the parameters of materials, bed and equipment, equilibrium constants and especially velocity and diffusion coefficient; contemporaneous, to chose a hidden back OLE algorithm to program and simulate a single fixed bed and equipment using Matlab software. Sequently, to used Presto software to simulate movement through bed and Aspen Adsorption software to optimize the simulation to achieve the highest productivity, stable product concentration; to studied the rules of changes in technological parameters of pressure, flow and concentration, especially pressure drop and factors affecting productivity and purity product. Study on the factors affecting the adsorption process, optimize a single fixed bed to optimize for N2 gas generator on a experimental system that has achieved N2 purity ≥ 99.5% stable with the highest product recovery. The mathematical model and simulation results are compatible with the built experimental system, with acceptable errors. 3. The thesis has studied industrial scale-up this equipment successfully by calculating and simulating on softwares at different productivity for specific applications in manufacturing and storage. Contemporaneous, the thesis has built a complete method by simulating and optimizing for air separators by molecular sieve adsorbent using the adsorption cycles. * New contributions of the thesis 1. The thesis has clarified the rule of pressure change in a single fixed bed and N2 gas generator according to the height of bed and time in a working cycle by a mathematical model is described by partial pressure of O2 (component is adsorbed), which is simulated by commercial and self-contained softwares successfully for N2 gas generator is a small capacity (pi-lot). 2. Having studied industry scaled-up for specific applications at suitable capacity successfully, that is achieving good results by calculation combined with simulation of separating technique by adsorption using pressure swing adsorption cycle and carbon molecular sieving adsorption material completely. 159 In addition, the thesis has built a systematic approach to simulate, optimize and scale-up of separator using molecular sieve adsorbents and the pressure swing adsorption cycle: from studying characteristics and structure of carbon molecular sieve adsorbents, calculating, design of a single fixed bed or equipment and calculation and analysis of pressure drop, velocity and diffusion coefficient for simulation and optimization of nitrogen gas generator by math model and software. This method can be applied to study other separative processes and equipments using molecular sieve adsorbents and adsorption cycles. * Further directions Results of the thesis, which shows that investigation of simulation and optimization for separative equipments to separate gase components from its mixture using PSA cycle and molecular sieve adsorption materials. Nowaday, this issue is very attractive in terms of science as well as practice and application in practice. These research results and methods have great potential for applications in chemical and petrol refinery industries, especially in substance separation techniques. Because this method can give results quickly, accuratetly and effectively. Some directions can be deployed to solve necessary science and fact problems in as follows, for example: - Investigate on simulating of temperature during adsorption and desorption processes in a single fixed bed of N2 gas generator using pressure swing adsorption. - Study on improving product purity and capacity of N2 gas generators using pressure swing adsorption by heterogeneous reaction technique to reduce O2 by H2 gas after nitrogen gas generator. - Investigation of simulation and optimization for O2 gas generator using pressure swing adsorption and zeolite 5A, 13X molecular sieve adsorbent to medical, supporting treatment for patients with Covid-19 in Vietnam. - Investigation of simulation and optimization for separation processes by PSA, VSA, TSA to separate CO2, H2, C2H5OH gases for fuel preparation, gas processing and other industrial components. 160 - Investigation of simulation and optimization for absolute alcohol production equipment by zeolite 3A using pressure swing adsorption. Because, simulation is a best method for deploying processes and equipment of chemical engineering. This method can give shorten time and high economic efficiency. Separation technique using the adsorption cycle and molecular sieve adsorbent is a potential field in the future. In addition, this method can be used to simulate and optimize the existing production line and other dissociation processes by Aspen Plus software. 161 THE SCIENTIFIC PUBLICATIONS 1. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2018). Assembling of an experimental system to investigate and optimize of nitrogen gas generator using pressure swing adsorption to separate nitrogen gas from the air. Journal of Military Science and Technology (ISSN 1859-1043), no. 56, p. 157-165. 2. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2018). Design a measuring and control system to investigate and optimize of nitrogen gas generator using pressure swing adsorption. Journal of Military Science and Technology (ISSN 1859-1043), special issue 08, p. 269-275. 3. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2019). Investigation of Simulation and optimization for nitrogen gas generator using pressure swing adsorption (PSA) by Aspen Adsorption Software. Journal of Military Science and Technology (ISSN 1859-1043), no.61, p.140-149. 4. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2019). Study comparative and selection of 4-step and 6-step using pressure swing adsorption to generate N2 gas. Journal of Catalytic and Adsorption Viet Nam (ISSN 0866-7411), Volume 8, Issue 3, p25-31. 5. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2019). Study on the carbon molecular sieve adsorbent CMS-240 used in the N2 gas generator. Journal of Military Science and Technology (ISSN 1859-1043), no.62, p97-105. 6. Pham Van Chinh, Nguyen Tuan Hieu, Nguyen Tan Y, Nguyen Hoang Nam, Do Van Thom, Ngo Thi Anh, Vu Dinh Tien (2019). Simulation and experiment study of a single fixed bed model of nitrogen gas generator working by pressure swing adsorption. Special Issue “Chemical Process Design, Simulation and Optimization” of Journal Processes (ISSN 2227-9717). Processes 2019, 7 (10), 654; https://doi.org/103390/pr7100654. 7. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2019). Establish a mathematical model to describe pressure swing adsorption in N2 gas 162 generator. Journal of Military Science and Technology (ISSN 1859-1043), special issue FEE – October, p357-364. 8. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2019). Study on simulation about partial pressure of oxygen in a single fixed bed of nitrogen gas generator using pressure swing adsorption. Journal of Military Science and Technology (ISSN 1859-1043), no.64 – December, p132-139. 9. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2019). Study on caculation and simulation of pressure drop through a single fixed bed of nitrogen gas generator using pressure swing adsorption. CASEAN-6 Proceedings (ISBN 978-604-913-088-5), p60-66. 10. Pham Van Chinh, Nguyen Tuan Hieu, Le Quang Tuan, Vu Dinh Tien (2020). Study on calculating the kinetic parameters of the mathematical model describing the adsorption process of a single fixed bed of N2 gas generator using pressure swing adsorption (PSA) and carbon molecule sieve adsorbent CMS-240. Journal of Catalytic and Adsorption Viet Nam (ISSN 0866-7411), Volume 9, Issue 1, p1-7. 163 REFERENCES Vietnamese 1. Võ Văn Bang, Vũ Bá Minh (2004). Quá trình và thiết bị Công nghệ Hóa học & Thực phẩm – Tập 3, Truyền khối. Nhà xuất bản Đại học Quốc gia – TP Hồ Chí Minh. 2. Nguyễn Bin (2008). Các quá trình, thiết bị trong công nghiệp hóa chất và thực phẩm, Tập 4: Chưng luyện, hấp thụ, hấp phụ, trích ly, sấy. 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