Research On The Utilization Of Oil And Light Of Oil From The Pyrolysis Of Waste Printed Circuit Boards

In the nowadays of accelerating technology, product replacement begin to speed up. We have to face the problem on how to treat the waste electrical and electronic equipment (WEEE), although we are enjoying the convenient from the latest technology. Printed circuit boards are the one of the most important components. The increasing amount of waste electrical and electronic equipment is leading to a large amount of waste printed circuit boards (WPCBs). WPCB are also become the typical waste solid in modern cities. WPCB are characterized by wide range and enormous amount. WPCB consist of resins, copper, glass fiber, etc. If all of comonents are utilized, it can not only bring the significant economic benefits, but also protect the environment. Among the different type of methods in recycling WPCB, yrolysis has the advantage that all of the pyrolysis products (pyrolytic oil(PO), metals and glass fiber) can potentially be recovered and recycled. Compared with copper and glass fiber, PO is difficult in recycling due to its complexity of the components and halogen in fire retardant. Therefore, there is no mature method in recycling the PO from the pyrolysis of WPCB.In this paper, the new method of recycling PO from WPCB was provided. Firstly, the optimal technological condition of preparing PO was determined. Then the PO was distillated into several fractions. All the liquid fractions were analyzed by element analyzer (EA), gas chromatoraph-mass spectrum (GC-MS), fourier transform-infrared spectroscopy (FT-IR). After that, the resource utilization on light fraction of PO (LFPO) and heavy fraction of PO (HFPO) were discussed. Finally, the effect on the light of PO in catalytic pyrolysis of WPCB was investigated.From the experiment of pyrolysis, the productivity of PO was18.6%while the optimal technological conditions were the particle size of40mm×40mm, the pyrolysis temperature of550℃, the heating rate of10℃/min, the pyrolysis pressure of20kPa and the constant temperature time of60min. and the productivity of solid and gas were76.1%and5.3%.After the true boiling point distillation (TBP) was carried. The major component was in120℃-300℃. All the fraction were analyzed by EA, GC-MS, FT-IR. The results showed that all the fractions consisted of over50%of C and6%of H. The C/H ratio of each fraction was0.8. Phenol and its substitutes were more than60%of pyrolytic oil. The spectrogram of the fractions of PO appeared characteristic peak such as CH2, CH-OH. Besides, less than10%of Br, which existed in bromophenolic compounds, was analysed in the pyrolytic oil.Through the orthogonal experiment, the thermosetting phenolic resin was synthetized by using LFPO. The results showed that the optimal technological conditions were LFPO of38.5g, formaldehyde of40g. NaOH of lOg of the catalyst, the reaction temperature of60℃for3h,and then ramp to95℃for3h. The thermosetting phenolic resin was observed by FT-IR and thermogravimetry (TG-DTG). The results indicated that the peaks such as CH2. CH-OH were appeared. The product begins to solidify and decompose at464.2℃, the remaining quality is64.71%at last, which indicated that the product has a good heat resistance. In the test of The tensile strength of the phenolic resin was39.6Mpa and its tensile modulus is8.8Gpa, which indicated that the phenolic resin has a good mechanical properties.In the field of using HFPO into modifying the asphalt, the The HFPO was tested as an asphalt modifier. Three asphalt modifiers were tested:HFPO; styrene-butadiene rubber (SBR); and HFPO+SBR (1:1). The physical properties and road performance of the three modified asphalts were measured and evaluated. The results have shown that when the amount of modifier was less than10%. the HFPO modified asphalt had the highest softening point of the three. HFPO+SBR modified asphalt did well in the test of penetration. SBR modified asphalt was good at the test of ductility. The dynamic stability (DS) and water resistance of the asphalt mixture with the HFPO modified asphalt was10161cycles/mm and87.2%, respectively. The DS was much larger than for the HFPO+SBR and SBR modified asphalt mixtures. These results indicate that using HFPO as an asphalt modifier has significant benefits not only for road engineering but also for resource recycling.In the research on the catalytic pyrolysis of WPCB, HZSM-5, USY, A12O3was used as there type of catalysts. The results showed that the productivity of liquid was the highest when using HZSM-5as catalyst. The resins of WPCB could decompose completely. USY had little effect on the productivity of PO. When the reaction temperature of catalytic pyrolysis was600℃, A12O3showed the best performance in the light of PO. The fraction (<200℃) was56%; HFPO was decreased by9%by the addition of HZSM-5; but USY didn’t show significant effect to the light of PO. A12O3had a dehalogen performance and in catalytic pyrolysis of WPCB. The results indicate that A12O3has a good performance in the light of PO and dehalogen. HZSM-5only do well in the light of PO. USY had little effect on the light of PO.This research can not only fill the gap of recycling of PO from WPCB, but also provide the theoretical guidance for popularization of pyrolysis process of WPCB.