- 學位論文
窯烤木柴燃燒產生空氣污染物之研究
Emission of Air Pollutants from Wood Combustion in Kilns
摘要
柴燒窯烤為近年來一種新興的飲食方式，因為可以替食材增添一道天然的果香味而受到大眾所喜愛，但其在柴燒作業過程中所產生的餐飲異味也時常造成附近居民的困擾，是容易遭受陳情的餐廳種類之一。因此，為瞭解柴燒窯烤木柴燃燒過程的污染物排放情形，本研究選用柴燒窯烤業者常使用的龍眼木及荔枝木兩種木柴進行柴燒窯烤模擬實驗，利用多氣體分析儀（Chemist 500X）、粉塵監測儀（EPAM-5000）、Tenax-TA採樣管及DNPH化學吸收液等材料設備分析尾氣中的二氧化碳、一氧化碳、總碳氫化合物、PM2.5、揮發性有機物及醛酮類化合物等污染物種，並予以不同的木柴含水率、批次燃燒量及通風量等實驗變因進行污染物排放情形的比較，計算之數據包括各污染物的排放濃度、排放速率及排放係數。 實驗結果顯示，污染物的排放情形與燃燒過程中的燃燒效率相關，低燃燒效率的條件下會有較高的污染物排放係數。木柴含水率高低對於木柴燃燒排放之二氧化碳、一氧化碳、總碳氫化合物、甲苯、乙苯、二甲苯、甲醛、乙醛、丙酮及丙醛排放係數具有顯著差異（P-Value＜0.05），除了二氧化碳平均排放係數於烘乾木柴高出25%外，未烘乾木柴之一氧化碳、總碳氫化合物、甲苯、乙苯、二甲苯、甲醛、乙醛、丙酮及丙醛平均排放係數分別為烘乾木柴的2.11、1.94、2.80、4.28、3.18、4.47、4.70、6.93、6.63倍；批次燃燒量的不同對於木柴燃燒排放之一氧化碳、總碳氫化合物、PM2.5、甲苯、乙苯、二甲苯、甲醛、乙醛及丙酮排放係數具有顯具差異（P-Value＜0.05），除PM2.5排放係數在1.0 kg燃燒量的條件下是0.5 kg燃燒量的2倍外，0.5 kg燃燒量之一氧化碳、總碳氫化合物、甲苯、乙苯、二甲苯及丙酮排放係數分別為1.0 kg燃燒量的2.19、2.21、2.35、2.38、2.50及2.94倍；通風量的高低對於木柴燃燒排放之一氧化碳、總碳氫化合物及丙酮排放係數具有顯著差異（P-Value＜0.05）。但可發現各污染物排放係數在高通風量的條件下有較高的排放係數，尤其是一氧化碳、總碳氫化合物、甲苯、乙苯、二甲苯、甲醛、乙醛、丙酮及丙醛等污染物。高通風量造成流速增加，空氣停留時間不足以進行完全的燃燒反應，且高通風量也同時降低了燃燒溫度，導致燃燒效率低，有燃燒不完全的情況，造成污染物的排放量增加。 而在兩種木柴間比較的部分，龍眼木與荔枝木燃燒所排放的各污染物種中，苯及二甲苯排放係數具有顯著差異（P-Value＜0.05），顯見木柴種類會對污染物排放情形造成影響；與其它文獻中木炭燃燒的污染物排放情形進行比較結果顯示木柴有較低的一氧化碳及總碳氫化合物排放係數，但在PM2.5、揮發性有機物及醛酮類化合物等具有較強毒性及致癌性的污染物種的排放係數較高，顯示柴燒窯烤此種烹飪方式也是一種不容忽視的污染源之一。
並列摘要
Wood-fired kiln roasting is an emerging way of eating in recent years. Because it can add a natural scent to the ingredients, it is popular among the public. However, the catering odor generated during the wood burning operation often causes troubles for nearby residents. It is one of the types of restaurants that is complained more often. Therefore, in order to understand the pollutant emissions of the firewood burning process in the wood-burning kiln, this study selected the Longan wood and litchi wood firewood, which commonly used by the wood-burning kiln to carry out the simulation experiment of the wood-fired kiln. With the using of a multi-gas analyzer (Chemist 500X), dust monitor (EPAM-5000), Tenax-TA sampling tube and DNPH chemical absorption equipment, etc. Analytical pollutant include carbon dioxide, carbon monoxide, total hydrocarbons, PM2.5, volatile organic compounds, aldehydes and ketones in the exhaust gas. Variables include different types of firewood, moisture content, wood charge and ventilation, are used to compare pollutant emissions. The calculated data includes the emission concentration, emission rate and emission factors of each pollutant. The experimental results show that the pollutant emission situation is related to the combustion efficiency in the combustion process, and there is a higher pollutant emission coefficient under the condition of low combustion efficiency. There is a statistically significant difference from the emission factors of carbon dioxide, carbon monoxide, total hydrocarbons, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, acetone and propionaldehyde between woods with different moisture content. The average emission factor of carbon monoxide, total hydrocarbons, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, acetone and propionaldehyde in high moisture content wood is 2.11, 1.94, 2.80, 4.28, 3.18, 4.47, 4.70, 6.93, 6.63 times higher, respectively. There is a statistically significant difference from the emission factors of carbon oxide, total hydrocarbon, PM2.5, toluene, ethylbenzene and xylene between 0.5 kg and 1.0 kg wood charge. Except for the PM2.5 emission factor, which is twice under the charge of 1.0 kg than of 0.5 kg. Other pollutants include total hydrocarbons, toluene, ethylbenzene, xylene and acetone are 2.19, 2.21, 2.35, 2.38, 2.50 and 2.94 times higher under the charge of 0.5 kg, respectively. The level of ventilation could affect pollutants emission from wood burning. There is a statistically significant difference from the emission factors of carbon monoxide, hydrocarbons and acetone among three different level of ventilation. However, it can be found that the emission factor of each pollutant has a high emission factor under high ventilation conditions, especially carbon monoxide, total hydrocarbons, toluene, ethylbenzene, xylene, formaldehyde, acetaldehyde, acetone and propionaldehyde. The high ventilation causes an increase in the flow rate, the air residence time is insufficient for a complete combustion reaction, and the high ventilation also lowers the combustion temperature, resulting in low combustion efficiency and incomplete combustion, resulting in an increase in pollutant emissions. Among the two types of wood, the benzene and xylene emission factor of the various pollutants emitted from the burning of longan and litchi wood are significantly different , which shows that the firewood type will discharge pollutants. Compared with the pollutants emssions from charcoal combustion in other literatures, the results show that wood has a lower carbon monoxide and total hydrocarbon emission coefficient, but it has higher emssions in PM2.5, volatile organic compounds and aldehydes and ketones. These pollutans are considered more toxic and are carcinogenic, indicating that wood-fired kiln roasting is also one of the sources of pollution that cannot be ignored.