浅析热风干燥技术中的节能途径

阐述了我国碳排放现状及节能减排的紧迫感。以传统的热风炉粮食干燥的和传统的木材蒸汽干燥为例,分析了传统干燥热效率不高的主要因素,指出排气余热回收是传统干燥作业节能减排的主要途径之一,采用普通换热器、热泵及热管换热器回收排气余热,均有明显的节能效果。采用普通换热器平均节能12.4%,采用热泵平均节能40%左右,采用热管换热器居二者之间。介绍了太阳能干燥、太阳能与热泵组合干燥、热风与真空微波组合干燥、超声波与热风干燥组合等各种低碳干燥技术。建议逐渐推广用生物质能源作为干燥的热源,有利于实现低碳干燥。     

第十四届全国干燥技术交流会取得圆满成功

2013年10月11日，第十四届全国干燥技术交流会在常州德群大酒店隆重召开。本次会议主要围绕本次大会的主题“绿色干燥，节能减排”展开，以节能技术、新型干燥技术、资源利用等为主线，报告干燥行业最新的发展趋势、节能减排技术、传质分离技术及节能、传热技术及节能等。     

第十四届全国干燥技术交流会取得圆满成功

2013年10月11日，第十四届全国干燥技术交流会在常州德群大酒店隆重召开。本次会议主要围绕本次大会的主题“绿色干燥，节能减排”展开，以节能技术、新型干燥技术、资源利用等为主线，报告干燥行业最新的发展趋势、节能减排技术、传质分离技术及节能、传热技术及节能等。     

关于举办2007′中国煤炭加工利用节能减排高层论坛暨技术展示会的通知

各会员单位、各煤炭企事业单位和有关设备制造厂家:去年以来,国务院发布了加强节能工作的决定,制定了促进节能减排的一系列政策措施。最近,国务院又发布了节能减排综合性工作方案。为贯彻落实国务院文件精神,真正把节能减排作为硬任务,充分认识节能减排的极端重要性和紧迫性,使经济增长建立在节约能源资源和保护环境的基础上,进一步促进煤炭工业节约发展、清洁发展、安全发展,实现经济又好又快发展,定于2007年11月4-6日在北京举办“2007′中国煤炭加工利用节能减排高层论坛暨技术展示会”。通过高层论坛和技术展示,大力宣传煤炭工业在发展煤…     

摩德娜引领窑炉节能减排发展潮流

在日前举行的佛山市陶瓷学会第十二届理事会三次全会扩大会议上,佛山市摩德娜机械有限公司总经理管火金重点介绍了企业的发展情况,技术总工荆海山作《窑炉节能减排的发展方向及摩德娜窑炉和干燥最新技术介绍》的专题报告,强调窑炉节能减排要从技术创新入手,     

2008年度煤炭工业节能减排先进企业(单位、个人)获表彰

为了加大煤炭行业节能减排工作力度，总结经验，表彰先进，进一步提高全行业节约能源资源意识，促进煤炭工业科学发展，中国煤炭工业协会、中国煤炭加工利用协会在全行业开展了煤炭工业节能减排先进企业、先进单位和先进个人的评选活动。     

大型粮食真空干燥设备的研究开发及应用

介绍了真空低温连续干燥新技术的发展背景，通过技术性分析，探索出了一条解决粮食干燥问题的新途径。加强新一代真空低温连续干燥新技术的推广和应用具有重要的现实意义，必将提高能源利用效率，起到节能减排的作用，为我国绿色干燥技术的发展指明了方向。     

冷冻与干燥能量循环利用技术的应用研究

在制冷工程中,制冷剂在冷凝过程中的热量往往被直接排放到周围环境而被浪费掉。从节能环保的角度出发,研究了有效提高压缩机排气温度以提升制冷剂所携带的热量品质,并通过换热回收将该部分热量用于干燥室烘干农产品的加工方法。此法既提高了系统整体性能系数,又节省了设备投资,对于伴随冷冻需求的农产品干燥加工有一定的指导意义。     

褐煤干燥技术发展及应用现状

论述了国内外褐煤干燥提质技术的发展现状。针对传统热力干燥在褐煤电厂应用中存在的高能耗、高投资和低安全性等问题,开展了褐煤过热蒸汽干燥机理的试验研究和中试试验。结果表明：过热蒸汽的干燥效果优于常规热空气;中试试验系统能稳定、连续地对褐煤进行干燥,且干燥产品符合褐煤干燥实际工业应用的要求。最后提出了过热蒸汽预干燥低质煤提质洁净煤技术（SCU技术）,对其在节能、安全等方面的技术先进性作了具体的对比分析,结果表明：SCU技术节能节水、安全性高,符合中国可持续发展战略和节能减排的要求。     

煤炭工业节能减排高层论坛在京举行

中国煤炭加工利用协会于2007年11月5—6日在北京21世纪饭店举办了“煤炭工业节能减排高层论坛”。这是煤炭行业积极推动节能减排工作向纵深发展的又一次重要活动。     

Calculation Steps for the Design of Different Components of Heat Pump Dryers Under Constant Drying Rate Condition

Heat pump–assisted dryers are an alternative method for drying heat-sensitive food products at low temperature and less relative humidity with lower energy consumption. The mathematical models of a heat pump dryer consist of three submodels; namely, drying models, heat pump models, and performance models. Heat and mass balance of both refrigerant and air circuits in all components of the system are used for development of mathematical models. The models are used for design of different components of heat pump dryers operating under constant drying rate condition. A simple stepwise design procedure for batch-type, closed-loop heat pump dryer is also presented.     

回热式热泵干燥高湿稻谷的试验研究

应用带有嵌入回热器的热泵装置,对华南地区高湿稻谷进行干燥试验,测定其干燥速率、能耗和品质。并与同期作业的燃油低温循环稻谷干燥机进行对照。试验结果表明：回热式热泵干燥机的干燥速率较燃油低温循环干燥机提高20％,干燥周期缩短约12％,而干燥能耗及费用可节省30％以上,干燥品质两者无差异。     

ON THE STUDY OF TIME-VARYING TEMPERATURE DRYING—EFFECT ON DRYING KINETICS AND PRODUCT QUALITY

ABSTRACT

The ability of heat pump dryer to produce controlled transient drying conditions, in terms of temperature, humidity and air velocity, has given it an edge over other drying systems. Exploiting this characteristic, we studied and compared the effect of different temperature-time profiles on the quality of agricultural products in a tunnel heat pump dryer capable of providing up to 14.6 kW of cooling capacity. The product quality refers to the color change of the products. Samples of banana and guava were dried in batches in a two-stage heat pump dryer. The effects of the starting temperature of a selected profile and the cycle time on both drying kinetics and product quality were studied. It was observed that by employing a step change in drying air temperature with the appropriate starting temperature and cycle time, it was possible to reduce significantly the drying time to reach the desired moisture content with improved product color.     

ON THE STUDY OF TIME-VARYING TEMPERATURE DRYING—EFFECT ON DRYING KINETICS AND PRODUCT QUALITY

The ability of heat pump dryer to produce controlled transient drying conditions, in terms of temperature, humidity and air velocity, has given it an edge over other drying systems. Exploiting this characteristic, we studied and compared the effect of different temperature-time profiles on the quality of agricultural products in a tunnel heat pump dryer capable of providing up to 14.6 kW of cooling capacity. The product quality refers to the color change of the products. Samples of banana and guava were dried in batches in a two-stage heat pump dryer. The effects of the starting temperature of a selected profile and the cycle time on both drying kinetics and product quality were studied. It was observed that by employing a step change in drying air temperature with the appropriate starting temperature and cycle time, it was possible to reduce significantly the drying time to reach the desired moisture content with improved product color.     

Saffron Drying with a Heat Pump–Assisted Hybrid Photovoltaic–Thermal Solar Dryer

Saffron is the most expensive spice and Iran is the largest producer of this crop in the world. Saffron quality is profoundly affected by the drying method. Recent research has shown that hybrid photovoltaic–thermal solar power systems are more efficient in comparison with individual photovoltaic and thermal systems. In addition, heat pump dryers are highly energy efficient. Furthermore, they are suitable for heat-sensitive crops such as saffron. Therefore, in the present study, the performance of a hybrid photovoltaic–thermal solar dryer equipped with a heat pump system was considered for saffron drying, in order to obtain a high-quality product and reduce fossil fuel consumption. The effect of air mass flow rate at three levels (0.008, 0.012, and 0.016 kg/s), drying air temperature at three levels (40, 50, and 60°C), and two different dryer modes (with and without the heat pump unit) on the operating parameters of the dryer was investigated. The results of the investigation showed that total drying time and energy consumption decreased as air flow rate and drying air temperature increased. Applying a heat pump with the dryer led to a reduction in the drying time and energy consumption and an increase in electrical efficiency of the solar collector. The average total energy consumption was reduced by 33% when the dryer was equipped with a heat pump. Maximum values for electrical and thermal efficiency of the solar collector were found to be 10.8 and 28%, respectively. A maximum dryer efficiency of 72% and maximum specific moisture extraction rate (SMER) of 1.16 were obtained at an air flow rate of 0.016 kg/s and air temperature of 60°C when using the heat pump.     

Heat Pump Drying of Green Sweet Pepper

Thin-layer drying experiments under controlled conditions were conducted for green sweet pepper in heat pump dryer at 30, 35, and 40°C and hot air dryer at 45°C with relative humidities ranging from 19 to 55%. The moisture content of sweet pepper slices reduced exponentially with drying time. As the temperature increased, the drying curve exhibited a steeper slope, thus exhibiting an increase in drying rate. Drying of green sweet pepper took place mainly under the falling-rate period. The Page equation was found to be better than the Lewis equation to describe the thin-layer drying of green sweet pepper with higher coefficient of determination and lower root mean square error. Drying in heat pump dryer at 40°C took less time with higher drying rate and specific moisture extraction rate as compared to hot air drying at 45°C due to lower relative humidity of the drying air in a heat pump dryer though the drying air temperature was less. The retention of total chlorophyll content and ascorbic acid content was observed to be more in heat pump–dried samples with higher rehydration ratios and sensory scores. The quality parameters showed a declining trend with increase in drying air temperature from 30 to 45°C. Keeping in view the energy consumption and quality attributes of dehydrated products, it is proposed to dry green sweet pepper at 35°C in heat pump dryer.     

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.     

水循环式热泵干燥装置的性能分析

水循环式热泵干燥装置是指热泵和干燥部分通过水循环耦合而成的热泵干燥系统，是一种中小型热泵干燥装置的结构型式。对水循环式热泵干燥装置的开机过程、调控特性、能源效率进行了分析，相关结论可为推广应用提供参考。     

内加热式热泵干燥装置的设计

内加热式热泵干燥装置通过导热加热方式提供物料中水分气化所需热能,可获得较高的能源效率和除湿能耗比。在介绍内加热式热泵干燥装置基本结构和工作过程的基础上,给出了其物料衡算、能量衡算和主要部件选型参数的计算公式,为内加热式热泵干燥装置的设计提供了较好的参考。     

热泵干燥装置的调控分析

热泵干燥具有节能、低温干燥及环境友好等特点，控制热泵干燥装置运行在较佳的状态，是保证热泵干燥装置效率和可靠性的基础。以带循环空气旁通的封闭式热泵,干燥装置为例，对热泵干燥装置的调控方法进行了分析，给出了装置的被控参数和一组较佳的控制参数，并建立了各控制参数的计算公式。