Nghiên cứu công nghệ cacbon hóa để xử lí chất thải đô thị ở Việt Nam

Nội dung text: Nghiên cứu công nghệ cacbon hóa để xử lí chất thải đô thị ở Việt Nam

1. Tieu ban: Moi tru&ng vd Ndng luang ISBN: 978-604-913-013-7 NGHIEN ClTU CONG NGHE CACBON HOA DE XtT LY CHAT THAI DO THI O VIET NA]VI Trinh Van Tuyen', To Thi Hai Yen', Shuji Yosizawa^ 'Vien Cong nghe moi tru6ng; "Dai hgc ting hgp Meisei, Tokyo, Nhat Ban trvtuven^hotmail.com Tom tat: Xu ly rdc thdi do thi theo cdng nghe nhiet phdn cd kiem soat khi thdi vd tgo ra sdn phdm la than cacbon cd hdm luang tdng cacbon huu ca (TOC) cao Idm nhien lieu trong cdng nghiep vd vdt lieu xie ly mdi tricdng la xu the phdt trien ben vieng cua ddt nude. Trong thdi gian qua, Vien Cdng nghe Mdi truang dd tien hdnh nghien cieu cdng nghe cacbon hod de xic ly chdt thdi rdn dd thi Hd Ndi vd da cd mdt sd ket qud khd quan cho viec dp dung vdo thicc te. Bdi bdo ndy trinh bdy cdc ket qud thu hdi sdn phdm, chdt luang sdn phdm thu duac ciing nhu dnh hudng cita cdc thdng sd cdng nghe nhu nhiet dd (T), thdi gian luu (t) den hieu sudt xic ly (rj), tdng cacbon hieu ca (TOC), dien tich be mat rieng (S). Nghien cieu duac tien hdnh tren 3 quy md khdc nhau: 10-20 g/me, 3-5 kg/me vd 50 kg/me. Cdc thuc nghiem duac tien hdnh vdi cdc logi hinh chdt thdi phd bien nhu gidy, gd, nhua, cao su, vdi Abstract: The treatment of municipal solid waste (MSW) using pyrolysis technology integrated with air emission control and product M'ith high TOC concentration which can be used as fuel for industrial production as well as material for environmental treatment system. This method can be seen as a solution toward sustainable development of our country. In recent years. Institute of Environmental Technology has been studying the carbonization technology to treat the municipal solid waste of Hanoi city. Some satisfactory results have been achieved. This paper presents the results about recovery ratio of product, product quality, and impacts of related parameters such as temperature (T), retention time (t), treatment efficiency (rj), total organic carbon (TOC), and the specific surface area (S). The research was carried out with 3 system scales: 10 - 20g/batch, 3 - 5kg/batch and 50 kg/batch. The experiments used common types of solid waste such as paper, wood, plastic, rubbers and textile. 1. MO DAU Co nhieu phuong phap xir ly rac thai do thi da dugc nghien ciiu va ap dung trong do co phuong phap thieu dit. Phuong phap thieu dit xir ly dugc nhilu loai chdt thai (dac biet la cac chat thai ran kho phan buy nhu plastic, da, cao su ) tilt kiem dugc dien tich cho cac bai chon lap. Tuy nhien, phuong phap thieu dot gay tac dgng xdu din moi truang khong khi, ngoai ra chi phi cho viec xir ly khi thai ciia qua trinh thieu dit rdt tin kem. Mot phuang phap xir ly moi ap dung doi vai chat thai ran giau cacbon bdng nhiet phan da bdt ddu dugc cac nha khoa 72
2. Hoi nghi Khoa hoc ky niem 35 ndm Vien Khoa hoc vd Cong nghe Viet Nam - Hd Noi 10/2010 hoc a Viet Nam va tren the gioi nghien cim. Cong nghe nay vira co the xir ly dugc 6 nhiem cua chat thai voi chi phi xir ly thap hon, vira tao ra dugc loai san pham tai che phuc vu kinh te xa hgi nhu than sach lam nhien lieu hoac vat lieu hap phu diing trong cong nghe xu ly 6 nhiem moi truang. Ban chat ciia phuong phap la dot cac chat thai ran chay dugc trong dieu kien thieu oxy hoac khong c6 oxy hoan toan [1-5]. Trong thai gian qua, Vien Cong nghe Moi tru6ng da tien hanh nghien cim cong nghe cacbon hoa de xir ly chat thai ran do thi Ha Noi va da co mot so ket qua kha quan cho viec ap dung vao thuc te. Bai bao nay trinh bay cac ket qua thu hoi san pham, chat lugng san pham thu dugc ciing nhu anh huong ciia cac thong so cong nghe nhu nhiet do (T). thoi gian lim (t) den hieu suat xir ly {r\), tong cacbon htiii co (TOC), dien tich be mat rieng (S). Nghien cim dugc tien hanh tren 3 quy mo khac nhau: 10-20 g/me, 3-5 kg/me va 50 kg/me. Cac thuc nghiem dugc tien hanh voi cac loai hinh chat thai pho bien nhu giay, go, nhua, cao su, vai 2. DOI TU^gfNG VA PHLTONG PHAP NGHIEN CtTU 2.1 Doi tuong nghien ciru: Chat thai do thi, cu the lay cac thanh phan chay dugc nhu: go. nhua, da, giay, cao su, vai 2.2 Phuong phap nghien ciru: - Phuang phdp thuc nghiem: dugc diing trong qua trinh nghien cim cong nghe cacbon hoa cac loai chat thai ran kho phan hiiy nham xac dinh cac thong so thuc nghiem toi im nliu thai gian, nhiet do, bieu suat thu hoi san pham de viec tien hanh ap dung cong nghe cho hieu qua cao ban. Qua trinh cacbon boa dugc tien hanh tren 3 quy mo thi nghiem khac nhau: quy mo trong tii dot voi khoi lugng 20-30 g/mau; quy mo 16 pilot 3-5 kg/me va quy mo 16 50 kg/me. Chat thai dugc xir ly theo mo hinh thuc nghiem nhu tren hinh 1. t Khoi 16 Khong khi ^ ' Buong gia nhiet Dau dot, Nhien 'V lieu dau DO Cira gio Quat ejector Ong khoi I Buong cacbon hoa Thiing chira chat thai < ^•n • Chat thai ran Hinh 1: Sa dd cdu tgo cita thiet bi thi nghiem pilot Mo ta thuc nghiem: Chdt thai dugc cho vao Thiing chira CTR, sau d6 dong kin nap thiing. Nli ong thoat khi tir ndp thiing voi quat ejector. Quat ejector c6 chirc nang lam thoal hoi am va cac khi bay ra tir buing cacbon boa. Ong khi thoat tir thiing chira chat thai den buong gia nhiet tilp xiic true tilp vai nggn lira tir dau dot nham xir ly khi sinh ra tir thiing carbon boa. 73
3. Tieu ban: Moi tru&ng vd Ndng luang ISBN: 978-604-913-013-7 Khi sinh ra chay se lam tang nhiet do buIng gia nhiet, nhu vay se giam chi phi nhien lieu cho qua trinh xii' ly. Tieu ban: Moi tru&ng vd Ndng luang 978-604-913-013-7 Cira gio lam viec theo chi do tu dgng va dilu khien bdng tay: khi nhiet do buong cacbon h6a c6n thdp chua dat din nhiet do cdn thiit thi cira gio lam nhiem vu huong nguIn nhiet di tir buIng gia nhiet xuIng buIng carbon boa. Khi nhiet do dat den gia tri can thiet da dat truoc, canh gio buong nguIn nhiet thoat tnre tilp ra Ing khoi va dau dot tu ngat va 16 dot lam viec theo che do ii nhiet. Ddu dit dugc dilu chinh tu dgng dl chay nhien lieu va cdp nhiet do cho qua trinh cacbon boa. Nhiet do c6 thi khing cbl tu dgng bdng rale dieu khien va van gio. Nhiet do thuc nghiem tir 300-500 °C, thai gian cacbon boa tir 10-60 phiit. - Phuang phdp phan tich: Phuong phap phan tich nhdm xac dinh cac tinh chat dac trmig cho chdt lugng san phdm than nhu dien tich bl mat rieng, chup kich thuac mao quan, xac dinh nhiet tri ciia san phdm, TOC. Cu thi, cac thiit bi dugc sir dung trong nghien cim nhu sau: + Trgng lugng: can co do chinh xac din hang gam AND HV-15 KgL - Nhat Ban; can OHAUSd-0.01g,ThuySi + Ham lugng cacbon hiru ca c6 trong than san pham: TOC Analyzer TOC-VCPH TNMl- Shimadzu 4100, Nhat Ban + Dien tich bl mat rieng, m2/g: Thiet bi Automatic Water Vapor Adsorption Apparatus Belsorp-18, Nhat Ban ; thiet bi Micromeritics M + cdu tnic, mat do 16: Thiit bi Scanning electron micrograph SEM (S-4700 Hitachi, Nhat Ban) + Nhiet tri: Thiit bi DTA-50 Shimadzu, Nhat Ban 3. KET QUA VA THAO LUAN 3.1 Thu'c nghiem carbon hoa cac thanh phan rac thai do thi Thuc nghiem dugc tien hanh trong 16 cacbon boa doi voi cac thanh phan chay dugc ciia chdt thai do thi nhu: giay, vai, cao su, go, nhua va hon hgp trgn theo ty le ciia chat thai. Lugng mau lay tir 2-20 g tiiy timg loai hinh chat thai. Nhiet do cacbon boa dugc tien hanh o cac giai nhiet do khac nhau: 300 C, 400 C va 500 C. Thai gian carbon h6a (thai gian luu) dugc tien hanh lay mau do dac: 10, 20, 30, 40, 50 va 60 phut. Ket qua thi nghiem doi vol giay dugc trinh bay a bang 1 sau day: Bdng 1: Cacbon hod gidy Nhiet do T= 300"C Ky Nhiet dd T= 400"C Nhiet dd T= 400"C hieu A B C D A B C D A B C D Ml 10 1,843 1,509 81,88 10 1,589 0,666 41,91 10 1,916 0,650 33,94 M2 20 2,042 0,725 35,50 20 1,663 0,417 25,12 20 2,187 0,596 27,25 74
4. Hoi nghi Khoa hoc ky niem 35 ndm I'ien Khoa hoc vd Cong nghe Viet Nam - Hd .Vd/ 10/2010 Ghi chii: A - Thdi gian cacbon hod (phitt); B - Khdi luang mdu (g); C - Khdi luang scm phdm (g); D - Hieu sudt thu hdi (%o). Thao luan: Trong khoang 10 phiit dau khoi lugng mau giam rat nhanh. Luc nay chii yeu xay ra hien tugng thoat hai nuac trong chat thai. Tiep theo den khoang 20 phut, qua trinh boc hoi ket thuc hoan toan va xay ra qua trinh hinh thanh cac thanh phan khi thoat ra. Tir 30 phut den 60 phut qua trinh khi hoa giam dan va on dinh. San pham c6n lai la than sach, hieu suat thu h6i on djnh doi voi giay a nhiet do 300 °C vao khoang 32-33%. () nhiet do 400^0, trong 10 phut dau qua trinh boc hoi xay ra rat nhanh va da bat dau binh thanh khi. Khoang 30 den 40 phut qua trinh cacbon hoa da bat dau on dinh. Hieu suat thu hoi 6n dinh doi voi giay 6 nhiet do 400 °C vao khoang 19-22%. Hieu suat thu hoi on dinh doi voi giay 6 nhiet do 500 °C vao khoang 18-21 %. Ket qua thi nghiem doi vol nhira dugc trinh bay o bang 2 sau day: Bdng 2: Cacbon hda ddi vdi nhua Nhid dd T= 30(fC Nhiet dd T= 400"C Nhiet do T= 400"C TT A B C D A B C D A B C D 1 10 16,823 11,459 68.12 10 16,240 9,520 58,62 10 17,143 7,906 46,12 2 20 15.100 7.161 47.42 20 17,006 6,851 40,29 20 13,245 4,484 33,85 3 30 12,745 4,718 37,02 30 14,622 5,747 39,31 30 14,402 4,235 29,41 4 40 11.870 4.342 36.58 40 14,458 4,372 30,24 40 15,145 4,101 27,08 5 50 13,230 4.793 36,23 50 15,231 4,595 30,17 50 16,352 4,129 26,25 6 60 16,353 5,802 35.48 60 16,856 4,993 29,62 60 14,346 3,747 26,12 Ghi chit: A - Thdi gian cacbon hod (phut); B - Khdi luong mdu (g); C - Khdi luang sdn phdm (g); D - Hieu sudt thu hdi (%). Thao luan: Hieu sudt thu hoi on dinh doi voi nhua a nhiet do 300°C vao khoang 35-37%; o nhiet do 400''C la 29-30% va a nhiet do 500°C vao khoang 26-27%. Nhu vay doi voi nhua ta co the tien hanh a nhiet do 400-500 °C, ty le thu hoi san pham 26-30%. 75
5. Tieu ban: Moi tru&ng vd Ndng luang ISBN: 978-604-913-013-7 Lam thi nghiem tuong tu a cac giai nhiet do va thai gian khac nhau doi vol cac loai chat thai khac nhu g6, da, tre ta co kit qua sau day: Hieu suat thu hoi doi vai giay tir 22-30%; Hieu sudt thu hIi dli vol nhua la 26-30%; Hieu sudt thu hIi doi vai vai tuong doi cao tir 60- 75% a nhiet do 300 - 400°C, nhung giam hdn xuIng c6n 14-59% a nhiet do 500°C; Hieu sudt thu hoi doi vai go: dat tir 15,5-25,2%; Hieu suat doi vai cao su la 20-35%). Kit qua van hdnh thiet bi pilot 3-5 kg/mi VA 50 kg/me. Sau hon 2 thang van hanh 16 carbon boa vol cac thanh phan chat thai khac nhau chiing toi thu dugc cac ket qua sau: Thofi gian de 16 dat den nhiet do on dinh: 10-15 phiit; Nhiet do buIng gia nhiet: 600-800°C; Nhiet do buIng carbon hoa: 300-500^^0; Thai gian carbon hoa 30-60 phiit, thai gian ii nhiet tir 240-300 phiit; Hieu sudt thu hIi dli vai giay la 30- 40%; voi go la 30-32,5%o; vai tre: 25-35,5%; voi trdu: 35-37%; voi loi ngo la 30%; va vai da va cao su la san pham ket chay dinh. 3.2 Xac djnh chat lugng san pham cua qua trinh carbon hoa - Xdc dinh TOC San pham dugc dinh huong de sir dung nhu nhien lieu dot cho cong nghiep va nhu vat lieu de xir ly 6 nhiem moi truang. De lam nhien lieu dot thi vat lieu khi dot phai sinh ra nhiet lugng cao, dac tnmg b6d thanh phan TOC c6 trong san pham. Tien hanh do TOC cho tat ca cac mau san pham da cacbon hoa o 300°C - 500°C trong cac khoang th6ri gian tir 10 phiit den 50 phut va thu dugc ket qua nhu sau (bang 3,4): Bdng 3: Ket qud TOC ciia gd Nhiet dd T= 300"C Nhiet do T= 400"C Nhiet dd T= 400"C Thdi gian TC IC TOC % TC IC TOC % TC IC TOC % (phiit) (mg) (mg) (mg) TOC (mg) (mg) (mg) TOC (mg) (mg) (mg) TOC Ml-10 5,908 0,035 5,873 58,73 6,315 0,005 6,312 63,12 6,882 0,027 6,857 68,57 M2-20 6,731 0,030 6,701 67,01 7,475 0,011 7,464 74,64 7,497 0,034 7,463 74,63 M3-30 7,520 0,008 7,512 75,12 7,278 0,022 7,256 72,56 7,630 0,008 7,622 76,22 M4-40 8,536 0,002 8,534 85,34 8,607 0,015 8,592 85,92 8,775 0,014 8,761 87,61 M5-50 8,651 0,006 8,645 86,45 8,891 0,009 8,883 88,83 8,920 0,007 8,913 89,13 Thao luan: Thanh phan TOC tang theo thai gian carbon hoa va nam trong khoang tir 60- 90%. So lieu nay c6 the cao hon neu nhu san pham dugc bao quan tot hon dl khong hut hoi am vao san pham; Gia tri TOC cao nhat khoang 88-89. Tuy nhien, nlu tinh din hieu qua thu hoi thi nen tien hanh qua trinh cacbon hoa a thai gian khoang 30-50 la phii hgp. Bdng 4: TOC ciia than cacbon hda Vdt lieu Tre Gd Gidy Da Ldi ngd Trdu TOC(%) 86,77 88,82 52,81 57,58 79,35 68,15 76
6. Hoi nghi Khoa hoc ky- niem 35 ndm Vien Khoa hoc vd Cong nghe Viet Nam - Hd Not 10/2010 Tir ket qua nay chiing ta thay thanh phan TOC ciia tre, gl va loi ngo tuong dli cao tir 80- 90%. Dieu nay noi len trien vgng ling dung cong nghe carbon hoa chdt thai thanh san pham than diing nhu nhien lieu sach. - Xdc djnh dien tich be mat rieng ciia san phSm Myc dich cua viec xac dinh dien tich be mat la de danh gia kha nang diing vat lieu nay lam gia the sinh hgc trong xir ly 6 nhiem moi truang. Cac hinh anh SEM cho thay cac san pham tir nguyen lieu go, tre rdt phii hgp dl lam vat lieu xu­ ly 6 nhiem moi truang vi kich thuoc mao quan va dien tich bl mat rdt phii hgp 10-150|am. Hinh 3: Hinh dnh SEM ciia than carbon hod cdc thdnh phdn chdt thdi: a) gd; b) tre; c) vdi; d) gidy Cac ket qua do kich thuoc 16 va dien tich be mat dugc trinh bay 6 bang 5. Bdng 5: Kich thudc vd dien tich be mat rieng cita cdc thdnh phdn chdt thdi (do tren thiet bi Micromeritics M) Logi than Kich thudc mao qudn Dien tich be mat (m^/g) Vai Kich thuoc rat nh6, phan Ion khoang l-2nm 60-70 Giay Kich thuoc nho, 1 -2nm 50-70 Tre 10-20)im (chilm 89.6%) 300 - 400 Go 50-150|im 100-300 77
7. Ti^u ban: Moi tru&ng vd Ndng luong ISBN: 978-604-913-013-7 KET LUAN 1) Carbon boa la phuang phap xir ly chdt thai co triln vgng do co mot so uu diem so voi cac phuang phap thong thu6ng khac nhu giam chi phi cho qua trinh dot. lugng khi thai sinh ra dugc kiem soat va c6 the dot true tiep de sinh nhiet. 2) Da tiln hanh thuc nghiem tren 3 quy mo thiit bi trong ph6ng thi nghiem va pilot tuong ling 2-20g/me; 3-5kg/me . 3) Da xac dinh hieu sudt thu hIi vai cac loai hinh chdt thai khac nhau a thai gian \uu nhiet tir 10-60 phiit a cac giai nhiet do 300, 400 va 500°C. Cu thi: hieu sudt thu hIi dli vol gidy tir 22-30% va tuong dli In dinh; dli voi nhua la 25-39%; doi vol vai tuong dli cao tir 60-75% o nhiet do 300, 400°C, nhung giam hdn xuong con 14-59% or nhiet do 500°C; dli vol go dat tir 15,5-25,2%; dli vol cao su la 20-35% . 4) Da tiln hanh phan tich cac chi tieu danh gia chat lugng san pham theo tieu chi nhi?t nang thong qua chi tieu TOC va nhiet tri cho thdy TOC cua cac san pham tuong doi cao tir 80-90%). Chi tieu vl vat lieu lgc dl xir ly 6 nhiem moi truong dugc danh gia thong qua chi tieu kich thuac mao quan va dien tich be mat rieng cho thay co the su dung lam vat lieu lgc. TAI LIEU THAM KHAO 1. Frank M. Gentry, "The Technology of low temperature", 1928. 2. FAO, "Simple technologies of charcoal making", 1983. 3. W.M. Qiao, Y. Song, S.H. Yoon, Y. Korai, I. Mochida Shiga, H. Fukuda, A. Yamazaki, "Carbonization of waste PVC to develop porous carbon material Without further activation ", 2005. 4. Kazuhiro Mochidzuki, Lloyd S. Peredes, and Michael J. Antal, Jr. Flash, "Carbonization of Biomass", 2002. 5. To Thi Hai Yen, Pham Thi Thu Ha, Kawai, Nguyen The Dong, Trinh Van Tuyen, Saburo Matsui, "Domestic solid waste - Remarkable resource of waste recycling in Vietnam", Vietnam - Korea Workshop on Resource Recycling, Hanoi October 2, 2007. 6. M.J. Antal, "Renewable Resources Research Laboratory", 2QQ1. 7. To Thi Hai Yen, Pham Thi Thu Ha, Nguyen The Dong, Trinh Van Tuyen, "Household solid waste in city - some results of study on present situation in Hanoi, Vietnam ", Tap chi Khoa hgc va Cong nghe, tap 46, so 3 (DB), 2008 8. Hoang Kim Co va nnk, "Tinh todn ky thuat nhiet Id cdng nghiep - tap 1 vd 2 ", NXB Khoa hgc va ky thuat. Ha Noi, 1985 78