Vertical Agitation Research Articles

Analysis of biogas production from palm oil mill effluent at different feed flow rates in biogas plant Sei Pagar Riau

Indonesia’s palm oil industry is considered one of the biggest in the world. Palm Oil Mill Effluent (POME) has the potential for further processing, which can be used as a substitute for boiler fuel (co-firing). Research on converting POME to biogas for boiler fuel (co-firing) in the oil palm plantation Sei Pagar Riau has been carried out. This study aimed to investigate and analyze the biogas production from Palm Oil Mill Effluent at different feed flow rates in Biogas Plant Sei Pagar Riau. Experiments were carried out using the Continuous Stirred-Tank Reactor (CSTR). The reactor capacity was 2000 m3. The reactor was equipped with one unit of vertical agitator and three units of horizontal agitators. POME was distributed from the fat pit unit to the pretreatment unit using the fat pit transfer pump. From the pretreatment unit, then POME proceeds to the reactor using the reactor feed pump started from 2.4 m3/h then gradually increase to 6.3 m3/h as the highest feed flow rate. Biogas was produced in the anaerobic reactor at mesophilic temperature. This study showed that an increase in the POME feed flow rate into the reactor also increases the production of biogas generated in the reactor. The biogas production began to increase every day, with the highest average biogas production of 167 m3/h. The methane concentration was also measured and showed that the highest methane concentration was on day 6, with a value of 70%. And then, the methane concentration trend decreased. However, it was relatively stable in the range of 62.1%-66.7% on day 18 to day 53. Based on this research, it was found that the optimal biogas production of the Biogas Plant in Sei Pagar Riau was generated when the POME feed flow rate was gradually increased and reached the maximum capacity according to its design.

Horizontal spin of ratchet motor by vertical agitation

The horizontal spin of a ratchet motor by vertical vibration is reported. A macroscopic ratchet gear is placed on a granular bed, where nearly half of the gear is penetrated in the bed. The gear and granular bed are mechanically vibrated. The gear shows a random motion or one-way spin that depend on the diameter of the granules, vibration frequency, and degree of vertical motion allowed for the gear. Even when one-way spin is observed, the spin direction depends on the abovementioned factors. Although the dependency is complicated, it is deterministic because the motion or flows of granular matter determines it. The characteristics observed in the experiments are explained by a simple model that accounts for the statistical variance in the motion of the granular matter. Extraction of systematic motion from small and non-useful motions such as mechanical agitation will be developed into energy harvest technology and may facilitate the science of a spontaneously moving system in a uniform potential field.

Forced fluid fluctuations in cylindrical reservoirs under vertical excitation

The shell and shell structures containing various types of liquid fillers can be exposed to intense dynamic effects during the exploitation. In order to analyze the strength of structures in these conditions, it is necessary to take into account nonlinear phenomena in fluid motion, since the application of linear equations does not provide an adequate assessment for the determination of the pressure and amplitude of the splashing. In this paper, a study of fluid fluctuations in a rigid cylindrical reservoir partially filled with the liquid under condition of vertical agitation has been carried out. The systems of differential equations that correspond to the linear and nonlinear formulation of the problem are presented. The fluid is believed to be perfect and incompressible, and its movement induced by external influences is non-vortex. Under these conditions there is a velocity potential that satisfies the Laplace equation. The conditions of non-leakage on the wetted surfaces of the shell are chosen as the boundary conditions for solving the boundary value problem. The kinematic and static conditions are specified on a free surface. The static condition consists in the equality of pressure on the liquid surface with atmospheric pressure. The pressure is determined from the Cauchy-Lagrange integral. In this case the linearization of the Cauchy-Lagrange integral leads to the linear formulation of the problem. Quadratic components are taken into account for the nonlinear formulation. To formulate the kinematic condition an additional unknown function describing the motion of the free surface is introduced. The kinematic condition is the equality of the liquid velocity described by the velocity potential and the velocity of the free surface itself. If there is a vertical agitation, an additional acceleration will be present. Therefore for the linear formulation we obtain a system of unbounded differential equations, each of which is the equation of Mathieu. This allows us to investigate the phenomena of parametric resonance. When analyzing differential equations which occur in case of a nonlinear problem, it has been found that the solutions of such equations depend essentially on the initial conditions. The phase portraits of a dynamic system with indication of resonances are presented. A numerical analysis of the differential equation corresponding to nonlinear formulation has been carried out.

시설하우스 온도 조절을 위한 수직형 교반 히터 자동제어 시스템

현재의 시설하우스에서의 난방 방식은 한 곳에 고정되어져서 위치에 따른 온도 편차가 심해 질 수밖에 없는 실정이다. 채소나 과일 작물 등을 재배하는 시설하우스는 적정 온도의 유지가 필수적인데 하우스 내부의 상하 온도 차이로 인해 적정 난방 또는 냉방을 위한 에너지 소모가 많다. 본 논문에서는 하우스 내부의 공기 순환을 효율적으로 할 수 있는 새로운 형태의 난방 방식인 수직형 교반 히터 자동 제어 시스템을 제안한다. 시설하우스 상 하부의 온도를 이용하여 수직형 교반 히터의 공기 순환 팬과 히팅을 상황에 맞게 독립적으로 제어함으로써 최소한의 전기 소비로 난방의 효율을 극대화 시켜 계획 가능한 작물 생산과 난방비 절감이 가능하다. As the current heating control of the greenhouse is located in specifically designed place, there is an inevitable difference in degrees depending on the latitude in it. Even though it is necessary to maintain the proper temperature in the greenhouse producing vegetables and fruit plants, the difference between ups and downs in the facilities results in the increasing energy consumption to both warm and cool down the facilities. The newest heating method, automatic control system of vertical agitation heater, which manipulates the inner air circulation efficiently, is suggested in this paper. The proposed system utilizes both the upper temperature and the lower temperature, and controls the air circulation fan and heating independently, so that maximizes the efficiency of heating with the minimum energy and implements predictable planning of farm products.

A non-rotational, computer-controlled suspension bioreactor for expansion of umbilical cord blood mononuclear cells

The proliferation and differentiation characteristics of umbilical cord blood mononuclear cells were examined in a non-rotational suspension bioreactor with a fishtail mixer. The system consisted of a glass vessel, a mixer that moved vertically, a data acquisition and control system to continuously monitor pH, temperature and dissolved O(2). The bioreactor provided superior expansion of total HSCs and not total cell number, as well as expression of stemness-related genes which followed with increasing in number of colony-forming cells during 14days of culture compared to T -lask culture. Vertical agitation thus reduces the total cell number, which may be related to increased shear stress, but has no effect on HSC function.

Fouling and fouling mitigation on heated metal surfaces

An apparatus was built to study heat transfer fouling on different heat exchanger pipe surfaces by visually observing the progressive fouling deposition under the same solution conditions. Test pipes were centrally located in a cylindrical tank with a concentric vertical agitator to give constant and uniform flow conditions near the pipe surface. Pipes with either smooth or roughened surfaces provided quantitative data on the progressive build-up and the composition of the deposits. The calcium sulphate deposition on four different metal surfaces (copper, aluminium, brass, and stainless steel) was investigated. The results show that fouling increases with time but at a decreasing rate over set intervals. The deposition also increases with the increasing thermal conductivity of the metal, or the total surface energy. Chemical reaction fouling along with particulate and crystallisation fouling occurred on reactive surfaces when corrosive chemicals were used, and this was compared with crystallisation-only fouling on non-reactive surfaces. Bleached Kraft softwood pulp fibres at various concentrations were added to the fouling solution to study their affects on fouling on the hydraulically smooth pipes. Fouling was retarded with only a low fibre concentration and reduced further as fibre concentration was increased.

Mineral scale formation and mitigation on metals and a polymeric heat exchanger surface

Abstract An experimental set-up was built to study heat transfer fouling of different pipe materials used in heat exchangers. Fouling mitigation investigations using wood pulp fibres in suspension in the fouling liquid were also performed. The new set-up allows progressive visual observation of fouling with time together with a recorded history under the same solution conditions. On completion, the tube under investigation could be removed to obtain quantitative data on the progressive build up of the deposit as well as the composition of the deposit. The experimental technique involved a pipe test specimen being centrally located in a cylindrical tank concentric with a vertical agitator to give constant and uniform flow conditions near the tube surface. The investigation of calcium sulphate deposition on four different metal surfaces (copper, aluminium, brass and stainless steel SS 316 respectively) and a polycarbonate surface reveals that the fouling increases with time but at a decreasing rate. The deposition on a metal surface can be seen to increase with increasing thermal conductivity and decreasing total surface energy over the range of experiments. Low surface energy material such as polycarbonate causes less attraction to the floating crystals and receives less deposition in comparison to the SS surface. Bleached Kraft softwood fibres at various concentrations were added to the solution to examine their effects on fouling. The results indicate that fouling is reduced as fibre concentration increases. It was also found that the fouling on stainless steel, brass and copper surfaces were all retarded in presence of fibre in the solution.

Effect of the agitation on the adsorption and hydrolytic efficiency of cutinases on polyethylene terephthalate fibres

The effect of agitation on adsorption, desorption and hydrolytic efficiency of a native and a genetically modified cutinase (L182A) on polyethylene terephthalate fibres is reported in this paper. The effect of mechanical agitation was studied using a shaker bath with orbital agitation and a Rotawash machine with vertical agitation with and without extra steel discs inside the reaction pots. The results obtained indicate that mechanical agitation combined with enzymatic action enhances the adsorption and activity of cutinases towards PET (polyethylene terephthalate) fibres. L182A showed higher adsorption than the native enzyme for all the levels of mechanical agitation. Lower units of L182A lead to similar yields of terephthalic acid formed in all levels of mechanical agitation. The highest increase of hydroxyl surface groups was found for the genetically modified L182A at the lowest level of mechanical agitation with a shaker bath. These results indicate that enzymatic functionalization of PET is favoured with a process with lower levels of mechanical agitation.

Method for Thermal Design of Paddle Dryers: Application to Municipal Sewage Sludge

An experimental methodology was developed to improve the energy design of paddle dryers for sewage sludges. A laboratory batch dryer with a vertical agitator has been especially designed and instrumented to determine the heat flux densities. To determine the drying kinetic and the evaporation rates, the specific heat and the total heat of desorption of the sludge were measured using calorimetric devices. The evaporating flow rates recorded during the pasty and granular phases were then used in a simple model of the paddle dryer. The good agreement between the computed drying kinetics and the experimental ones measured in an industrial paddle dryer shows that the batch dryer can be used to classify the sludges according to their capacity to be dried in a paddle dryer.

Wet granular matter under vertical agitation

We have studied the effect of small amounts of liquid on the dynamic behaviour of a granularsystem consisting of spherical glass beads under vertical agitation. The critical accelerationΓcrit at which fluidization sets in is found to increase strongly when liquid is added. Itfurthermore depends upon sample parameters such as the bead size and the shakingfrequency. A simple model is proposed which accounts quantitatively for our results andsuggests that fluidization by vertical agitation is mainly a surface phenomenon.

Comparison of coal liquefaction yields from two different reactor systems: The importance of loading and mixing in determining batch autoclave results

High conversions in NiMo- and NaAlO 2NiMo-catalysed no-solvent hydrogenation of a low-rank coal were obtained in a 35 mL reactor (1 g coal charge) heated in a horizontal position with vertical agitation. Much lower conversions were obtained in a 55 mL reactor (3 g coal charge) heated in a vertical position with a stirrer; however, the favourable effect of NaAlO 2 addition in giving high oil/asphaltene ratios was preserved. The effects of addition of solvent (tetralin and decalin) and varying the coal loading in the 55 mL autoclave showed the importance of good accessibility of the reactant gas to the coal particles.

Sieving Control and Horizontal Agitation of Potato Harvester Chains

ABSTRACT THE performances of two types of prototype potato harvesters were investigated. One was fitted with a primary web (chain) delivering to a secondary web which was agitated horizontally, either parallel or perpendicular to the direction of travel. Agitation perpendicular to the direction of travel gave up to 30% better clod break-up, but 13 to 23% higher damage than agitation parallel to the direction of travel. The other machine embodied a variable area primary web, agitated vertically or horizontally. Tests indicated that horizontal agitation can improve sieving and reduce potato damage by 17% to 30%. Varying the effective sieving area can improve efficiency of clod break-up and soil loss, without the need to change from the optimum web/forward speed ratio. Doubling the web area with vertical agitation reduced clod by up to 37% and increased the damage index by up to 33%.