蒸汽与热泵联合干燥木材的匹配分析

对单独的常规蒸汽干燥、热泵(除湿)干燥以及二者联合干燥三种工况进行了能耗分析，结果以联合干燥能耗最低，热泵(除湿)干燥次之，常规蒸汽干燥能耗最高。文中还就相应干燥条件下蒸汽-热泵(除湿)联合干燥的匹配条件作了研究。     

黄河流域产粮地区推广粮食干燥机的前景分析

黄河流域是我国主要粮食产区，但农业机械化水平很低，粮食干燥机械化水平更低。结合目前该地区的农业生产条件，对比分析了影响黄河流域粮食干燥机发展的主要原因。对几种实现粮食干燥机械化的模式进行了比较，并研讨了实现这几种模式的操作方法。回顾了我国近年来的农业政策，并展望了未来的农业政策。虽然目前的粮食干燥机械化程度不蓉乐观，但在国家政策的支持下，各级政府的努力下，在不远的将来实现粮食干燥机械化的目标是不容质疑的，但需要投资，需要做大量的宣传、引导工作。     

陶瓷工业干燥技术与设备

陶瓷产品的干燥是陶瓷生产工艺中非常重要的工序之一。干燥是一个技术相对简单，应用却十分广泛的工业过程，其不但关系着陶瓷的产品质量及成品率，而且影响陶瓷企业的整体能耗和生产成本。据统计，干燥过程中的能耗占工业总燃料消耗的15％，而在陶瓷行业中，用于干燥的能耗占燃料总消耗的比例远不止此数，因此干燥过程的节能是关系到企业生存的大事。     

粮食干燥装置节能减排技术的研究与实践

针对东北地区粮食干燥机系统能耗高、污染重的现状并根据对现有的塔式粮食干燥装置的考察分析,进行了节能减排方面的技术改造。采取了尾部干燥段和冷却段废气回收、烟气余热利用、设备保温处理和更换高效换热器等措施,使换热器进风口的平均风温比大气温度提高了30℃以上,排烟温度降低了30℃以上,节煤10％以上,废气中的皮屑和粉尘回收率可达80％以上。该技术改造在多个示范库点进行了实施,收到了明显的节能减排效果。     

湿氟化铝的干燥脱水

介绍三种湿法氟化铝的干燥脱水工艺及其产品质量和能耗。其中ＬＩＮＺ工艺的干燥能耗较低，Ａ－Ｐ工艺操作易于控制。     

生物质型煤干燥能耗的瞬态分析及预测模型

通过在不同干燥温度(140,160,180℃)、不同风速(0.4,0.8,1.2 m/s)下对生物型煤进行了干燥特性实验,并对其瞬时单位能耗进行了计算和分析,结果表明:生物质型煤干燥过程中,单位能耗曲线分为3个阶段:下降阶段、恒定阶段和上升阶段;当干燥速率处在升速阶段时,单位能耗随干燥温度和风速的提高下降迅速;当干燥速率处在恒速阶段时,单位能耗随干燥温度和风速的提高而降低;当干燥速率处在降速阶段时,单位能耗随干燥温度和风速的提高而快速上升。基于干燥特性数学模型——Sabbet方程,得到了生物质型煤干燥时瞬时单位能耗的预测模型,其可以有效地反映出生物质型煤在干燥过程中单位能耗瞬态变化,为生产和工艺改进提供指导。     

节能环保的玉米真空干燥设备

传统热风干燥设备热效率低，排放到大气中的烟气污染周围环境，干燥玉米破损率高，浪费粮食。利用真空干燥设备干燥玉米，干燥过程要求的温度低，加热介质不直接排放大气，不但没有环境污染，而且余热可回收再利用，可以实现王米在低温下干燥，做到节能环保，同时由温差引起的热应力较小，玉米破损率低，节约了粮食资源。     

中国通用机械工业协会机械工业信息研究院文件关于举办“第一届干燥设备节能减排先进技术高峰论坛”的通知

各有关单位： 干燥设备行业是我国装备制造业的重要组成部分,广泛服务于国民经济的各个领域。干燥行业是一个耗能巨大的行业,其所用能源占我国国民经济总能耗的12％左右。目前国内干燥技术能源利用率只有40％～50％,国外则达到70％以上。因此,在化工、石化、医药、建材、轻工、饲料、食品、造纸、木材、粮食等行业推广节能干燥技术至关重要。     

离心流化床中的干燥特性的实验研究

报道了多种不同形状的萝卜、韭菜等蔬菜及粮食种子在离心流化 中干燥特性的实验结果，得出了恒速干燥阶段的传热准数关联式，并找出了影响整个干燥过程干燥速率的因素，同时讨论了不同操作条件对干燥速率的影响。     

高温除湿与常规蒸汽联合干燥的试验与分析

讨论了高温除湿与常规蒸汽联合干燥过程中干燥室内空气温度、相对湿度及木材含水率的变化趋势，分析了干燥过程中除湿量及能耗的变化规律。实验结果显示，高温除湿与常规蒸汽联合干燥节能效果显著，干燥质量好。高温除湿机可以直接放在木材干燥室内部工作，无需对干燥室窑体进行改装。     

Performance of Two Industrial Dryers for Fish Feed

Performance and energy efficiency of two types of dryers for fish feed are compared. The first dryer was a belt dryer located at a fish feed production facility in Norway. The second dryer was a counterflow multideck dryer at a fish feed production facility in Chile. In both dryers there was only a slight decrease in drying rate over the dryer. Product samples showed a standard deviation of 0.45% on an average moisture content of 10.2% (wb) for the belt dryer and 0.49% on an average of 8.6% (wb) for the counterflow dryer. Mass and heat balances showed good accuracy. In order to compare the energy use of both dryers, normalized energy consumption and efficiency were calculated for equal feed and air inlet temperatures using two methods: the primary energy method and the energy difference method. The average normalized specific energy consumption for the belt dryer was 3,386 kJ/kg water evaporation (primary energy method) and 2,970 kJ/kg (energy difference method), with efficiencies of 56 and 64%, respectively. For the counterflow dryer the average specific energy consumption was 2,893 kJ/kg (primary energy method) and 2,393 kJ/kg (energy difference method), with efficiencies of 70 and 85%, respectively.     

Process Parameters Optimization for Energy Saving in Paper Machine Dryer Section

Due to high energy consumption in the Chinese paper industry, this study considers higher-energy efficiency for the multicylinder dryer section of paper machines. A common situation in the Chinese paper industry is that energy is consumed in extensive mode. In order to improve the energy efficiency of the paper machine dryer section, deeper analysis and optimization of process parameters are necessary.

A NLP optimization method is developed for integration of steam system and air system to reduce the steam consumption and decrease the loads of centrifugal blowers in the multicylinder dryer section of a paper machine. Equality constraints of the optimization model are extracted from different process modules based on material and energy balance. Inequality constraints are from the production capacity, operating condition, etc. Two illustrative examples are presented in this paper. The results show that the optimization model is adaptive and convenient for application. For a newsprint machine, less dry air and steam are used and the energy consumption can be reduced by about 8% in the dryer section. Applied on a linerboard machine which has surface sizing, the method can reduce the energy consumption by 5.6%.     

Dynamic Analysis of Drying Energy Consumption

A concept of instantaneous drying and energy efficiencies has been applied to analyze energy consumption in a through-circulation conveyor dryer and a batch fluid bed dryer for synthetic rubber. It is shown that the energy performance of the conveyor dryer can be improved by leveling of the moisture content distribution across the material layer by mechanical agitation, and sectioning of the air plenum in order to reduce inlet air temperature in the last two sections of the dryer. It is also shown that drying of a synthetic rubber in the fluid bed dryer is more energy-efficient than in the conveyor dryer, especially in the constant-rate period. Thus, the largest energy savings could be obtained in a two-stage dryer comprised of the plug-flow fluid bed dryer, and the belt conveyor dryer for removal of the bulk and residual water, respectively.     

Energy system diagnosis of paper-drying process,Part 1: Energy performance assessment

Paper drying is a highly energy-intensive and complicated multivariate process. The dryer section plays an important role in the energy consumption of a paper machine, especially of thermal energy. A comprehensive method for assessing the energy performance of the dryer section was investigated in this study to improve energy efficiency. This method was divided into three component processes: energy and evaporation load audit, field test and observation, and energy flow analysis and energy efficiency estimation. In a case study, we found that the method could, in addition to analyzing the key factors that restrict drying efficiency, also depict the details of energy consumption clearly. At the same time, several significant energy-saving measures were suggested to improve the energy efficiency of the paper-drying process.     

Dynamic Analysis of Drying Energy Consumption

Abstract

A concept of instantaneous drying and energy efficiencies has been applied to analyze energy consumption in a through-circulation conveyor dryer and a batch fluid bed dryer for synthetic rubber. It is shown that the energy performance of the conveyor dryer can be improved by leveling of the moisture content distribution across the material layer by mechanical agitation, and sectioning of the air plenum in order to reduce inlet air temperature in the last two sections of the dryer. It is also shown that drying of a synthetic rubber in the fluid bed dryer is more energy-efficient than in the conveyor dryer, especially in the constant-rate period. Thus, the largest energy savings could be obtained in a two-stage dryer comprised of the plug-flow fluid bed dryer, and the belt conveyor dryer for removal of the bulk and residual water, respectively.     

A MATHEMATICAL MODEL FOR CONTINUOUS DRYING OF GRAINS IN A SPOUTED BED DRYER

A mathematical model for a continuous spouted bed dryer has been presented to predict moisture content, air and grain temperatures as well as energy consumption. To better understand the interactive influence of processes in each region of the spouted bed, solution schemes for the spout and downcomer were treated separately. The behavior of dryer was investigated experimentally and found that the dryer behaved differently from an ideal plug flow. The drying rate as simulated by the model is almost constant during grain movement in the dryer. Absence of airflow in the downcomer leads to a tempering process that takes place in the downcomer while intense heat and mass transfer occurs mainly in the spout due to the high airflow rate there. Furthermore, by considering the predicted grain temperature history as one of the indicators of product quality, one can, in principle, design appropriate successive processes in a continuous spouted bed dryer to minimize product damage.     

Parallel plate heat exchanger for heat energy recovery in a farm grain dryer

One of the methods with the most potential to reduce energy consumption in grain drying is heat recovery from the dryer exhaust air. A parallel plate heat exchanger to recover heat energy from the exhaust air of a recirculating batch grain dryer was examined by theoretical assessments as well as by measurements in a scaled-down research dryer and experimental heat exchanger. In addition to the heat transfer performance, the operability in dusty conditions was investigated. Finally, the optimization of the heat exchanger was introduced by the aid of the calculation models and practical measurement. The heat exchanger performed satisfactorily, providing an average energy saving of approximately 18%. A significant improvement in the performance could be achieved by increasing the air velocity. No severe dust accumulation was observed, and a heat exchanger of this type could provide remarkable energy saving possibilities in grain drying. Further tests are necessary to ensure the operability in long-term use.     

Frozen Water Content in Maize at Low Temperatures And Its Effect on Dryer Performance

In some parts of the world, e. g. China, maize reaches a grain dryer at low temperatures, frequently in the range of -10°C to -20°C. The effect of a low grain temperature, and an equally low ambient temperature, was determined, partially by experimentation and partially by simulation. The percentage of moisture Frozen in maize depends on the grain moisture content and temperature. The low grain and ambient temperatures surprisingly have only a small effect on dryer capacity; however. the influence on the energy consumption is large.     

Efficient Energy Recovery with Wood Drying Heat Pumps

This article presents a 13-m³ wood dryer coupled with a 5.6-kW (compressor power input) heat pump. Drying tests with hardwood species such as yellow birch and hard maple were completed in order to determine the system's energy performance. Supplementary heating to compensate for the dryer heat losses was supplied using electrical coils or steam exchangers. The heat pump running profiles and dehumidification performance in terms of volumes removed and water extraction rates, coefficients of performance, and specific moisture extraction rates were determined for two all-electrical and two hybrid drying tests. The hardwood drying curves, share of the final moisture content, and final quality of the dried wood stacks, as well as total drying energy consumption and costs, were determined for each drying run. Finally, the total energy consumption of the drying cycles using a heat pump was compared with that of a conventional drying cycle using natural gas as a single energy source.     

Performance Analysis of an Electric Clothes Dryer

Improving the energy efficiency of clothes dryers has been the subject of numerous investigations. However, to date the clothes drying process has not been thoroughly tested or analyzed in a comprehensive study. Many of the techniques that have been proposed to improve energy efficiency add to dryer cost or are environmentally unacceptable. In the present study, a commercial Frigidaire dryer was instrumented and evaluated for energy performance by changing operating parameters including heater power, fan speed, drum speed, weight, and initial moisture content of the clothes. The total drying time and energy consumption was monitored as well as the effect of air leakage into the drum. The experimental results from 32 runs of the dryer were evaluated. The results from these tests are discussed and techniques are proposed in an attempt to improve the energy efficiency of this unit.