材性法制定木材干燥基准的探索

提出了一种新的木材干燥基准制定法——材性法。与常用的百度法相比,材性法更省时、简易、准确。采集简单易测的待干木材材性数据,如基本密度、厚度、初含水率等,材性法可以快速地制定出木材干燥基准。介绍了材性法的理论基础、制定方法及试验验证。     

木材干燥基准的研究现状及展望

木材干燥基准是控制木材干燥过程中干燥介质的参数表。介绍了木材干燥基准的重要意义、类别、制定方法、研究现状等方面内容，指出了未来干燥基准的研究方向。     

预处理对榆木干燥特性的影响

利用百度试验对预处理榆木的干燥特性进行分析。结果表明：热水处理试件与冷水处理试件材相比较,干燥特性存在明显差异。热水处理榆木初期开裂等级最大为2级,截面变形等级最大为2级;而冷水处理榆木初期开裂等级最大为4级,截面变形等级最大为3级;热水处理榆木从30％到5％所用时间平均为13．41a,含水率从30％到1％平均干燥速度为5．16％／h;而冷水处理榆木从30％到5％所用时间平均为14．03h,含水率从30％到1％平均干燥速度为2．8％／h。     

褐煤干燥及复吸特性试验研究

为考察褐煤干燥过程中干燥温度、干燥时间等条件对褐煤脱水效果的影响,以及获得用于估计褐煤干燥效果和干燥时间的半经验关联式,在自主研发的单炉处理量为3kg的低温热解试验系统中进行了褐煤干燥试验,获得了干燥温度及干燥时间对预热段的干燥效果影响不大,但对恒速干燥段的影响明显,降速干燥段次之的定性结论。     

粉煤灰干燥特性的试验研究

对所用的粉煤灰进行了粒度分析并测得其物理性质;在不同的干燥工况下对粉煤灰做了大量试验,对实验数据进行了拟合,建立干燥特性方程,针对影响干燥速率的主要因素及热质传递规律进行了分析。结果表明,粉煤灰所含水分大部分为非结合水,温度、风速对粉煤灰的干燥速率影响明显;堆积的粉煤灰穿流干燥时不具有典型的3个干燥阶段。试验结果可为粉煤灰干燥器的设计提供依据。     

宝日希勒褐煤干燥特性试验研究

为确定褐煤干燥工艺参数,选用宝日希勒褐煤在160～200℃条件下进行了不同粒级煤样的恒温干燥试验。将试验结果与6种薄层干燥模型进行拟合,利用相关系数对模型进行评价。结果表明：在160～200℃温度范围内,不同粒度宝日希勒褐煤的干燥速率曲线均呈现升速和降速两个阶段,干燥速率随干燥温度的升高而增大,1～13 mm的粒度范围内,煤样质量相同时,平均干燥速率随粒度的增大而增大。Page1模型作为宝日希勒褐煤的干燥动力学方程,拟合效果最好。     

杨木APMP与杨木化学浆配抄对纸张性能的影响

研究了典型的国产高得率浆杨木碱性过氧化氢机械浆(APMP)与杨木化学浆配抄对纸张有关性能的影响。结果表明,杨木APMP的比例在50%时,纸张松厚度和不透明度分别增加了39%和9%;同时,纸张平滑度和强度性能有所下降,但由于杨木APMP具有较高的细小纤维含量,因此在一定程度上抵消了其负面影响。     

微波干燥玉米籽粒的试验研究

针对玉米热风干燥中存在的问题。运用自制的微波干燥试验设备。采用不同的质量比功率和加热时间及配套的工艺流程。研究了玉米微波干燥特性及干燥条件对干燥品质、能耗的影响；分析了微渡干燥玉米过程中单位质量功耗、温度、平均失水速率与玉米籽粒发芽率、爆腰率和淀粉得率的关系；确定了影响微波干燥玉米的工艺参数和玉米微波干燥的合理工艺流程。研究结果表明：玉米微波干燥主要处于恒率干燥阶段，应用微波技术既能快速而经济地对玉米籽粒进行干燥，又能保持其种用价值，且有利于改善其品质。     

射流冲击流化床干燥的试验研究

设计试制了一种可对颗粒物料进行连续与批式干燥的射流冲击综合试验装置。在此基础上，对颗粒物料射流冲击干燥进行了系统试验研究，得出了射流冲击干燥装置的结构参数、工艺参数与干燥机性能间的关系，建立了射流冲击干燥的数学模型。     

利用热泵干燥污泥技术的试验研究

为了对热泵干燥污泥的方法进行研究,采用自行设计的污泥热泵干燥装置对含水率为55%-60%的污泥进行干燥试验研究。分析了风量、空气参数、冷凝温度和蒸发温度等对干燥效果的影响。试验表明,风量、空气参数、冷凝温度和蒸发温度对干燥效果有较大的影响,随着风量的增大,出水量逐渐增多,在风量达到800-1000m3/s,达到一个最佳的干燥效果,此时能耗比为0.73。     

Drying kinetics of poplar lumber during periodic hot-press drying

The drying kinetics of poplar lumber was experimentally investigated as a function of drying temperature (115, 135, 160, 185 and 205°C) during a periodic hot-press-drying process. Poplar lumber was dried under contact (compression ratio of 10%) and high-press states (compression ratio of 44%). Compared with the contact-state, the high-press-state showed higher drying rate and higher efficiency of removing free water than bound water in wood. Eight mathematical models from the literature were established to analyze the drying behavior. The Weibull model, with an average determination coefficient R² of 0.9958, fitted well for all applied drying conditions. The scale parameter decreased with increasing drying temperature and was lower for high-press-state drying compared with that for contact-state drying. Moisture diffusivity and activation energy were calculated according to the Weibull model. Diffusivity increased with increasing drying temperature, with the average value of 1.734?×?10^?6 and 3.313?×?10^?6?m²/s and activation energy of 34.79 and 32.85?kJ/mol for contact-state drying and high-press-state drying, respectively. Hot-press drying created an M-shaped curve of density distribution, with high density at the two surface regions gradually decreasing toward the core region. The contact state-dried wood showed increased density near the wood surface. Both average density and peak density improved in the case of high-press-state-dried wood. Furthermore, the hydrophilic index of wood for high-press-state drying was lower than that of the contact-state drying, and the opposite was true regarding crystallinity index. The hygroscopicity of high-press-dried poplar decreased with lower equilibrium moisture content and higher moisture excluding efficiency, compared with contact-state-dried poplar. The rapid, high-quality drying of poplar lumber through periodic hot-press was more potentially achieved by the high-press-state compared with contact-state drying.     

2种方式干燥的天然橡胶干燥特性之研究

为探讨微波干燥天然橡胶新技术，分别在温度115℃下，采用电热烘箱产生热空气和微波干燥装置干燥湿天然橡胶胶粒，对二者的干燥特性及硫化胶性能进行对比分析研究。结果表明，微波干燥只需13．467min就可使胶料含水量降至0．791％，热空气干燥则需211min。天然橡胶微波干燥和热空气干燥主要包含失水率加速期、失水率减速期、失水率相对恒速期3个失水阶段。整个干燥过程中，微波干燥失水率较大，而热空气干燥失水率比较小。微波干燥天然橡胶硫化胶的耐热氧老化性能得到显著提高：其老化前后拉断伸长率变化率（-35％）和拉伸强度变化率（-59％）明显高于热风干燥天然橡胶硫化胶的拉断伸长率变化率（-62％）和拉伸强度变化率（-89％）。     

聚烯烃织物背胶干燥特性及干燥模型研究

研究了聚烯烃织物背胶在不同干燥温度和风速时的干燥曲线、干燥速率曲线、水分有效扩散系数(Deff)以及干燥活化能(Ea),建立了干燥的数学模型。研究结果表明:聚烯烃织物背胶的整个干燥过程属于降速干燥,干燥温度和风速的升高都有利于缩短干燥时间;Page模型能较好描述聚烯烃织物背胶的干燥过程,并且Deff为(2.46~4.15)×10-8m2/s,Ea为26.95 kJ/mol。     

Study on drying kinetics of calcium oxide doped zirconia by microwave-assisted drying

Ca–ZrO₂ is an essential structural and functional material, which is commonly used in refractories, electronic ceramics, and functional ceramics. The properties of Ca–ZrO₂ materials are depending on the quality of Ca–ZrO₂ powders. The main factors affecting the quality of powder are sintering temperature and the drying effect. This paper applied modern microwave drying technology to dry Ca–ZrO₂ powder. The impact of initial mass, microwave heating power, and initial moisture content on the drying of Ca–ZrO₂ were explored. The results showed that the average drying rate increased with the rise of initial mass, microwave heating power, and initial moisture content. Wang and Singh, Page, and Quadratic Model were applied to fit Ca–ZrO₂ with an initial moisture content of 5.6%, mass of 30 g, and microwave output power of 400 W. The results displayed that the Page model had a better fitting effect. It was also applicable to other different initial moisture content, original mass, and microwave heating power. The diffusion coefficient calculated by Fick's second law displayed that with the increase of initial mass, initial moisture content, and microwave heating power of Ca–ZrO₂, the effective diffusion coefficient increased first and then declined. When the Ca–ZrO₂ of microwave heating power was 640 W, mass was 30 g, and the moisture content was 5.65%, the effective diffusion coefficients of zirconia were 1.42533 × 10^?13, 2.91806 × 10^?13, 5.652.2471 × 10^?13 m²/s, respectively. To determine the activation energy of microwave dried zirconia, using the relationship between microwave power and activation energy, the activation energy of microwave dried zirconia was calculated to be ?23.39 g/W. This paper aims to rich experimental data for the industrial application of microwaves to strengthen dried zirconia and propose a theoretical basis.     

酒石酸吉他霉素冻干法研究

虚用冻干法制备酒石酸吉他霉素,比用喷干法制备的成品收率高,成本低,流动性好,溶解速度快,残留溶媒低,其理化指标符合标准规定因此,通过测定成品酒石酸吉他霉素效价、色级等理化指标,对成盐工艺、冻干曲线进行优化选择。     

给定曲线的远红外烘干微机控制系统研究

研制了远红外烘干微机控制系统。该系统采用PC机作为上位机，运用可视化编程语言VB6．0设计出友好的人机操作环境，整个系统能按照操作人员在PC机上绘制出的干燥工艺曲线进行干燥作业，实现干燥过程的自动控制，从而可减少寻找最佳干燥工艺曲线的时间及人力与物力。系统还具有数据动态显示和自动存储等功能。经现场使用表明，该系统工作稳定可靠、操作简单方便，确保了物质烘干质量的提高。     

电石渣干燥特性的研究

研究了电石渣的干燥过程以及干燥过程中Ca(OH)2的转化率,结果表明:150℃下恒温干燥电石渣,因物料的初始干基含水量较大,电石渣的预热阶段时间较长,而恒速干燥阶段时间短暂,干燥速率为0.08kg(水)/kg(绝干物料)/min,电石渣的临界含水量为11.6%;当电石渣干基含水量达到其平衡水分时,电石渣中Ca(OH)2的转化率为12.08%。     

脲醛树脂喷雾干燥实验研究

研究了脲醛树脂乳液喷雾干燥过程工艺条件,探讨了热风温度,压缩空气压力,蠕动泵转速等因素对喷雾干燥过程的影响。从而得到粉末脲醛树脂产品,质量达国内引进装置生产的粉状脲醛树脂的质量指标,应用结果优于GB/T 14732-1993的各项指标。     

Drying timber in a solar kiln using an intermittent drying schedule of conventional laboratory kiln

The purpose of this study was to apply an intermittent drying schedule developed from a conventional kiln to a solar kiln. Implementing this experiment could help better understand the oscillation of the temperature inside a solar kiln and timber quality during drying progress. The theoretical recharge and discharge curves were used to predict the temperature inside the solar kiln using experimental data obtained previously using a solar kiln. The surface and internal checks were measured using ImageJ freeware, and the development of the Moisture Content (MC) profile was assessed by coring and slicing method for the Eucalyptus delegatensis boards during drying. The results showed that the recharge and discharge model can predict the temperature with less than 2?°C error from the experimental data in the solar kiln. The total drying time to 12% MC was 87?days for the solar kiln. The drying rate was equivalent to the conventional kiln decreasing at an average rate of 0.2% per day. The surface check formation was found when the MC gradient between the core and the case of the board was greater than 42% at 9?days of drying in the solar kiln and conventional laboratory kiln. The applied drying schedule used in the solar kiln was successful and offered similar drying time. However, the oscillation of temperature in the intermittent drying will require further improvement to get closer conditions in a solar kiln.