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林业科学 ›› 2020, Vol. 56 ›› Issue (12): 130-135.doi: 10.11707/j.1001-7488.20201215

• 论文与研究报告 • 上一篇    下一篇

杉木和辐射松锯材高温干燥对甲醛释放的影响

江京辉1,周凡1,周永东1,*,李伯涛1,付宗营1,韩振泰2,高鑫1   

  1. 1. 中国林业科学研究院木材工业研究所 北京 100091
    2. 中国林业科学研究院森林生态环境与保护研究所 北京 100091
  • 收稿日期:2019-05-24 出版日期:2020-12-25 发布日期:2021-01-22
  • 通讯作者: 周永东
  • 基金资助:
    “十三五”国家重点研发计划“木材节能备料与质量控制技术研究”(2016YFD0600701)

Effects of High Temperature Drying on Formaldehyde Releases of Chinese Fir and Radiata Pine Lumber

Jinghui Jiang1,Fan Zhou1,Yongdong Zhou1,*,Botao Li1,Zongying Fu1,Zhentai Han2,Xin Gao1   

  1. 1. Research Institute of Wood Industry, CAF Beijing 100091
    2. Research Institute of Forest Ecology, Environment and Protection, CAF Beijing 100091
  • Received:2019-05-24 Online:2020-12-25 Published:2021-01-22
  • Contact: Yongdong Zhou

摘要:

目的: 以40 mm厚人工林杉木和辐射松锯材为研究对象,分析高温干燥过程中温度和锯材含水率对甲醛释放浓度的影响,并与辐射松锯材常规干燥甲醛释放浓度作比较,回收释放的甲醛,探讨高温和常规干燥过程中温度和锯材含水率对甲醛释放量的影响规律以及甲醛回收措施。方法: 根据干燥过程中温度和锯材含水率分布情况,杉木锯材高温干燥采样7次,辐射松锯材高温和常规干燥分别采样9和10次,抽气速度为1.0 L·min-1,采样时间为30 min。参考EPA method 0011,利用冰水浴方法,将2个200 mL洗气瓶内装40 mL蒸馏水串联放入冰水槽中,使醛类物质充分溶于水,采用乙酰丙酮法测定甲醛浓度。结果: 杉木和辐射松锯材高温干燥(90~120℃)时,干燥过程中甲醛释放浓度最小值和最大值分别为4.21和11.43 mg·m-3、3.66和12.71 mg·m-3,均高于无组织排放标准规定限值0.20 mg·m-3;在90~120℃范围内,干燥温度与甲醛释放浓度呈线性关系,其决定系数(R2)分别为0.668和0.934,即随着干燥温度升高,甲醛释放浓度增加;当干燥温度为105℃时,随着辐射松锯材含水率降低甲醛释放浓度逐渐增加,呈线性关系,决定系数(R2)为0.885;干燥温度是影响甲醛释放权重比例最大的因子。在辐射松锯材常规干燥中,干燥温度小于90℃以及锯材含水率逐渐降低时,甲醛释放浓度基本恒定,其值为(0.19±0.03)mg·m-3,低于无组织排放标准规定限值,常规干燥排出气体中甲醛浓度符合排放标准。结论: 当干燥温度大于90℃时,应对干燥排出的气体采取回收措施,以避免污染环境。

关键词: 杉木, 辐射松, 高温干燥, 含水率, 甲醛释放

Abstract:

Objective: In this paper, the Chinese fir (Cunninghamia lanceolata) and radiata pine (Pinus radiata) lumber with 40 mm thickness were subjected as materials. During high temperature kiln drying, formaldehyde concentration was analyzed as effected by temperature and moisture content of lumber, and was compared to that of conventional kiln drying radiata pine lumber. Method: During the lumber drying, according to the temperature in kiln and moisture content distribution of lumber, as for high temperature drying, the discharged gas of Chinese fir and radiata pine lumber were sampled 7 and 9 times, respectively; while for conventional drying, the discharged gas of radiata pine lumber was sampled 10 times. The extraction speed was 1.0 L·min-1 and the time was 30 min. Referring to EPA method 0011, two 200 mL gas washing bottles with 40 mL distilled water were put in series in ice bath to make aldehydes fully dissolved in the water. Then the formaldehyde concentration was measured by acetyl acetone method. Result: As for Chinese fir and radiata pine lumber in high temperature ranged from 90℃ to 120℃, the minimum and maximum formaldehyde concentrations were 4.21 mg·m-3 and 11.43 mg·m-3, 3.66 mg·m-3 and 12.71 mg·m-3, respectively, which were all higher than the requirement limit of the non-organized emission standard that formaldehyde concentration didn't beyond 0.20 mg·m-3. The drying temperature was linear with the released formaldehyde concentration in the temperature range of 90-120℃, and the determination coefficients (R2) were 0.668 and 0.934, respectively. When the drying temperature was 105℃, the concentration of formaldehyde increased gradually with the decrease of moisture content of radiata pine, they were negatively linear relationships, and the determination coefficients (R2) was 0.885. However, the drying temperature was the most important factor affecting the weight of formaldehyde release. During the conventional kiln drying, when the temperature of kiln did not beyond 90℃ and the moisture content of radiata pine lumber decreased gradually, the released formaldehyde concentration was almost constant with (0.19±0.03) mg·m-3, and was less than the requirement limit of the non-organized emission standard of formaldehyde concentration. Conclusion: When the drying temperature is higher than 90℃, the gas discharged during drying should be recycled to avoid environmental pollution.

Key words: Chinese fir, radiata pine, high temperature drying, moisture content, formaldehyde release

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