Giaotrinhcongnghe Xu Ly Khi

7/29/2019 Giaotrinhcongnghe Xu Ly Khi

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Prepared by Ha quoc Viet pro Eng gas comp platform page 2

Phan ln cac he thong s ly dau kh eu co cac thanh phan chung nh hnh 1.1.Chung c cau tao t cac module co chc nang va nhiem vu khac nhau.

Hnh 1.1: He thong thu gom, x ly dau kh

Bao gom va san pham va cac gieng khai thac.:

- Dong san pham t va i len bao gom ca chat long, kh, nc, cac hat ran do o phai co cac bnhtach e tach rieng dau kh nc goi la bnh tach cap 1.- Cac cap bnh tach tiep theo co nhiem vu on nh thanh phan dau tho nham at yeu tang tr hayvan chuyen.

:Bao gom cac thiet b s ly phan nc khai thac cung san pham dau kh t va va c tach qua

cac bnh tach qua trnh nay nhan thu hoi hydrocacbons, loai bo cac tap chat ran, hay cac chat ranhoa tan nh CaCO3, NaCl. Nham muc ch at yeu cau ve chat lng thai ra moi trng hoac tai

s dung. : (gian nen kh trung tam)Xem hnh 1.2Nhiem vu chnh nham loai tr cac tap chat (nc, tap chat ran, cac chat oc hai H 2S, CO2,

N2, O2...) trc khi a en module che bien kh.e loai nc ngi ta co the dung cac bien phap nh: hap thu thng dung glycol, chathap phu nh silica gen, alumina hay molecular sieve (zeolite), ngng tu nhiet o thap,

: (nha may Dinh Co)


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Xem hnh 1.2Nhien vu cua phan nay bao gom tach hon hp kh t nhien thanh cac thanh phan rieng biet

(thong thng la cac kh hoa long) nh Ethane (C2), Propane (C3) , Butane (C4), natural gasoline(C5+)

Hnh 1.2: He thong thu gom, x ly, che bien dau kh


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THONG SO VAT LY CUA N CHATCac thong so vat ly cua mot n chat la hoan toan xac nh theo cac bang sau:

Hnh 2.1 Bang thong so vat ly


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Hnh 2.2 : Bang thong so vat ly


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Hnh 2.3: Bang thong so vat ly


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GIAN O PHA CUA N CHAToi vi chat rieng biet bao gi cung ton tai iem ti han (C: critical point) tai o tng ng ta coap suat ti han Pc va nhiet o ti han Tc

Hnh 2.4: Gian o pha cua n chat C2H6

Khi nhiet o va ap suat cao hn nhiet o iem ti han khi ay n chat trong vung dense phase ola vung trang thai mot pha, vat chat trong vung nay co cac tnh chat vat ly (the tch rieng, khoilng rieng, entanphy, o nht ) la trung gian gia chat kh va long. Nh vay trong vung nay takhong the thay oi cac thong so cong nghe e a chat o ve trang thai hai pha c, ieu o congha la qua trnh hoa long mot phan hay toan bo kh mot cau t bang phng phap nen ch thchien c khi ha nhiet o kh o xuong di nhiet o ti hanKhi i t a xuong b (ang nhiet, giam ap) n chat chuyen t long sang kh, khi i t e qua d (angap, giam nhiet ) th n chat chuyen pha t kh sang long.GIAN O PHA CUA HON HP KH NHIEU CAU T

Hnh 2.5: Gian o pha cua hon hp kh.


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Trong hon hp hay dung dch kh nhieu cau t , vung ti han thng la mot khoang rong cac thongso va phu thuoc vao thanh phan kh. Xet trang thai he nhieu cau t trong gian o P,T hnh 2.5, hnh2.6:Ta thay co cac lu y:

iem ti han C , tai o hai pha tr thanh mot phaiem B (cricondenbar) iem tng ng vi ap suat ln nhat ma o hon hp co the trang

thai hai phaiem T (cricondenthermal) iem tng ng vi nhiet o ln nhat ma tai o hon hp co theton tai trang thai hai pha.Nhng gia tr cc ai cua ap suat va nhiet o ma tai o hon hp nhieu cau t co the ton tai trangthai hai pha c goi la nhiet o va ap suat ngng tu ti han cua hon hp.

Hnh 2.6: V tr vai thong so tren gian o phaV tr tng ho cua cac iem C, B, T tren gian o P,T phu thuoc vao thanh phan cua hon hpTren gian o P,T phan ng ben trai cho ti C la ng iem soi (bubble) con phan ng ben

phai la ng iem sng (dewpoint )Trong cac qua trnh thuan th khi nen len, hoac khi giam nhiet o th chat long ngng tu tang lenCon ngc lai khi nen len hay khi giam nhiet ma lng chat long ngng tu giam i th o la quatrnh (ngng tu , bay hi) ngc.Trong cong nghe kh ngi ta hay dung may nen e nen kh tang ap, expander e giam ap, vangiam ap, trao oi nhiet e tang giam nhiet, quat giam nhietKhi at ieu kien thch hp mot caut nao o cua kh bat au ngng tu tat nhien kh co nhiet o ngng tu cao nhat se ngng tu trctuy nhien ta chu y cac cau t kh co tnh chat hoa tan c trong hydrocacbon long nh vay chacchan mac du mot vai cau t cha u ieu kien hoa long th chung a hoa tan mot phan sang thelong.Mc o ngng tu cac H-C se tang khi ap suat tang nhiet o khong oi, hoac khi giam nhiet o

ap suat khong oi. Tuy nhien qua trnh ngng tu cua hai trng hp tren se say ra khac nhau, khitang ap th cac cau t nhe b hoa tan vao pha long cang nhieu len ieu nay khong tot, khi tang aphay giam nhiet th cac cau t nang chuyen sang pha long nhanh hn.Cong thc qui oi nhiet o:


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NHIET O TI HAN Tc, AP SUAT TI HAN Pc:oi vi n chat Tc, Pc la cac thong so a biet qua hnh 2.1, 2.2, 2.3oi vi hon hp sau khi phan tch thanh phan hon hp ngi ta tnh Tc, Pc nh sau:

yi: la phan mole cua cau t trong hon hp.V du: Tnh toan cac thong so nhiet o ti han Tc, ap suat ti han Pc, khoi lng phan t MW, he

so khong ong bo (acentric) W theo cong thc cho hon hp nh sau:

ai lng ac trng cho s phan bo cac cau t gia cac pha trong ieu kien can bang c goi lahang so can bang pha. No c xac nh bang phng trnh:

yi la phan mol cua cau t trong pha hi, xi la phan mol cua cau t trong pha longKi phu thuoc vao ap suat , nhiet o, va ap suat hoi tu (ap suat ma o cac hang so can bang cuatat ca moi thanh phan eu bang 1) cua he.Ap suat hoi tu c xac nh theo thanh phan cua pha long can bang (ma thanh phan pha long naycung la an so) do o thng th ta chon mot ap suat hoi tu cho he long sau o tra cac Ki, tnh toanra thanh phan long kh, sau o t thanh phan long can bang ta lai tnh ra ap suat hoi tu neu ap suathoi tu chon va tnh toan giong nhau th o la ket qua ung. Trong thc te trong cac he dau kh coap suat di 50 bar th cac hang so can bang Ki khong phu thuoc ap suat hoi tu khi o qua trnh

tnh toan c n gian hoa i rat nhieu.e tnh ap suat hoi tu theo cac bc nh sau :Chuyen pha long can bang thanh he bac hai gia trong o cau t th nhat la cau t nhe, co lngkhong t hn 0,1%mole, cau t th hai la gom cac cau t con lai.Tnh nhiet o ti han trung bnh khoi va ap suat ti han trung bnh khoi oi vi cau t gia nangtheo phng trnh:

Tci(k) Pci(kpa) yi MW i Mwi*yi Pci*yi Tci*yi w i yi*w i

C1 190.56 4599 0.7 16.043 11.2301 3219.3 133.392 0.0104 0.00728

C2 305.41 4800 0.1 30.07 3.007 480 30.541 0.0979 0.00979

C3 369.77 4240 0.05 44.097 2.20485 212 18.4885 0.1522 0.00761

iC4 407.82 3640 0.03 58.123 1.74369 109.2 12.2346 0.1852 0.005556

nC4 425.1 3784 0.02 58.123 1.16246 75.68 8.502 0.1995 0.00399

iC5 460.35 3381 0.015 72.15 1.08225 50.715 6.90525 0.228 0.00342

nC 5 469.65 3365 0.015 72.15 1.08225 50.475 7.04475 0.2514 0.003771nC 6 506.4 3030 0.01 86.117 0.86117 30.3 5.064 0.2994 0.002994nC 7 539.2 2740 0.01 100.204 1.00204 27.4 5.392 0.3494 0.003494

nC 8 568.4 2490 0.01 114.132 1.14132 24.9 5.684 0.3977 0.003977nC 9 594.7 2280 0.01 128.258 1.28258 22.8 5.947 0.4445 0.004445nC10 617.7 2100 0.01 142.258 1.42258 21 6.177 0.4898 0.004898CO2 304.11 7374 0.01 44.01 0.4401 73.74 3.0411 0.2667 0.002667H2S 373.37 8963 0.005 34.082 0.17041 44.815 1.86685 0.0948 0.000474N2 126 3399 0.003 28.0134 0.08404 10.197 0.378 0.0372 0.0001116H2O 647 22118 0.002 18 0.036 44.236 1.294 0.3443 0.0006886Total 1 27.9528 4496.758 251.9521 0.0651662

Mw Pc(kpa) Tc(k) W


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Sau o anh dau tren hnh 2.7 v tr cau t gia nang co tung o va hoanh o la P tbk, Ttbk , bang conng noi suy gia cac ng cong ti han bac 2 co tren o th chung ta ve ng cong ti han caut nhe-cau t gia nang.T ng cong ve c va ap suat ban au cua he iem giong t nhiet o qua ng cong chnh laap suat hoi tu.

Hnh 2.7: o th kiem tra ap suat hoi tu


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Sau o so sanh ap suat hoi tu chon va tnh toan neu sai khac khoang di 12% la chap nhan c.ng dung he so can bang trong tnh toan dong kh qua bnh tach nh sau:zi la phan mol cua cau t trong dong kh vao bnh tach, yi la phan mol cua cau t trong pha hi, xila phan mol cua cau t trong pha longF tong so moles kh vao bnhV tong so moles khi ra khoi bnh

L tong so moles chat long ngng tu

Phng trnh can bang vat chat Fzi = Vyi + Lxi; F=V+L , Ki=yi/xiThay vao Fzi = Vyi+Lxi , yi =Ki*xi => Fzi = Vki*xi + Lxi =xi(L+Vki)e n gian ta xet F=1 khi o xi = zi/( L+Vki)Ta chu y xi = 1 nh vay zi/( L+Vki) =1 trong phng trnh nay zi a biet, Ki tra theo P,T, ta chcan thay L (t 0 en 1) e cho zi/( L+Vki) =1 la cDong kh vao bnh tach co the khong co ngng tu chat long khi o L = 0, V=1 khi nay bai toan laxac nh ieu kien dewpoint P,Thay dong kh ngng tu hoan toan L=1, V= 0 khi o bai toan la xac nh ieu kien bublepoint

solution02)Trc khi lam bai toan nay ban phai chac chan hon hp vao bnh phai la trang thai hai pha th khio mi co phan chia long kh. Cac ieu kien di ay cho phep ban d oan trang thai dong khvao bnh tach :Neu kizi va (zi/ki) ca hai eu ln hn 1 th dong vao bnh la 2 pha

kizi nho hn 1 th dong vao la toan long , kizi = 1 dong vao la bublepoint(zi/ki) nho hn 1 th dong vao la toan kh, (zi/ki) = dong vao la dewpoint.kizi va (zi/ki) se khong ong thi nho hn 1

Cho P=4140kpa, T= -30o C ta chon L sao cho total cot G=1 va cot H=1 la he can bang, co P, T tra

bang ra Ki (lu y Kco2=(Kc1*Kc2)0,5

)A B C D E F G HMoles Ni Ki L moles V moles L+Vki xi=Ni/(L+Vki) yi=Ki*xi

C1 0.901 3.7 0.03 0.97 3.6189 0.2489710 0.9211926

CO2 0.0106 1.23 0.03 0.97 1.2231 0.0086666 0.0106599

C2 0.0499 0.41 0.03 0.97 0.4277 0.1166644 0.0478324

C3 0.0187 0.082 0.03 0.97 0.1096 0.1706587 0.0139940

IC4 0.0065 0.034 0.03 0.97 0.063 0.1031463 0.0035070


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Cho P=3400kpa T= -30C ta chon L sao cho total cot G=1 va cot H =1 la he can bang, co P, T tra Kivi ap suat hoi tu 1500psi.Solution 47 , Solution 48Kiem tra ap suat hoi tu:

Da vao hnh 2.7 ta nh v iem co ve ng cong i qua iem nh vva iem cau t nhe metan, t nhiet o lam viec 30oC giong len ng cong a ve, giong tiep sangtruc ap suat c 1500 psi, do o ket qua tnh toan qua bnh tach tren la chnh xac.


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Hnh 2.11: o th tra he so can bang K cua C2H6ap suat hoi tu 1500psi


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Hnh 2.13: o th tra he so can bang K cua C3H8ap suat hoi tu 1500psi


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Hnh 2.14: o th tra he so can bang K cua iC4H10ap suat hoi tu 1500psi


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Hnh 2.15: o th tra he so can bang K cua nC4H10ap suat hoi tu 1500psi


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PHNG TRNH TRANG THAI CUA KH HYDROCACBONPhng trnh c ban P: ap suat hon hp kh (kpa)V: the tch hon hp kh (m3)Z: he so nenn: so moles hon hp kh

R: hang so kh = 8,3145T: nhiet o hon hp kh (oK)CHNG TRNH TNH HE SO NEN Z: THEO VAN DER WAALSZ^3-(1+B)Z^2+AZ-AB=0

A=a*P/(R^2T^2)

B=bP/R/T

a=27R^2Tc^2/64/Pc

b=RTc/8/Pc

CHU Y Z CH UNG KHI F(Z)=0CHNG TRNH TNH HE SO NEN Z: THEO PENG ROBINSONZ^3-(1-B)Z^2+(A-2B-3B^2)Z-(AB-B^2-B^3)=0

A=a*P/(R^2T^2)

B=bP/R/T

a=0,45724R^2Tc^2/Pc* ^0,5=1+m(1-Tr^0,5)b=0,0778RTc/Pc m=0,37464+1,54226W-0,26992W^2

CHU Y Z CH UNG KHI F(Z)=0 Tr=T/TcCHNG TRNH TNH HE SO NEN Z: THEO REDLICH -KWONGZ^3-Z^2+(A-B-B^2)Z-AB=0

A=a*P/(R^2T^2.5)

B=bP/R/T

a=0,42747R^2Tc^2,5/Pc

b=0,0867RTc/Pc

CHU Y Z CH UNG KHI F(Z)=0CHNG TRNH TNH HE SO NEN Z: THEO REDLICH KWONG BARXUKZ^3-Z^2-(m^2+m-d*m)Z-dm^2=0

b=bi*yi m=Pb/R/T

d=di*yibi=0,0867RTc/Pc

di=Ai+Bi(Tc/T-1)+Ci(Tc/T-1)^2

CHU Y Z CH UNG KHI F(Z)=0Cac he so lay nh sau:

Tci Pci(kpa Ai Bi Ci

C1 190,56 4599 4,934 8 1,5

C2 305,41 4880 4,934 8,3 0

C3 369,77 4240 4,934 8,82 0

IC4 407,82 3640 4,934 9,3 0

NC4 425,1 3784 4,934 9,35 0

IC5 460,35 3381 4,934 9,4 0

NC5 469,65 3365 4,934 9,5 0NC6 506,4 3030 4,934 10 0NC7 539,2 2740 4,934 10,5 0NC8 568,4 2490 4,934 11 0NC9 594,7 2280 4,934 11,2 0nC10 617,7 2100 4,934 11,6 0CO2 304,11 7374 3,5 6,8 0H2S 373,37 8963 4,26 6,5 0Total


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oi vi hon hp kh hydrocacbon thPc = yiPci ; Tc = yiTciChnh xac hn cac thong so nay co trong bang tra

Hnh : Gian o pha cua kh hon hpNhn tren gian o pha khi hon hp ang trong trang thai long, ta tang nhiet o cho en iem 1 ngvi nhiet o Ts(P) th bat au co hi hnh thanh ta goi nhiet o nay la nhiet o soi bao hoa ng viap suat P, iem nay co trang thai la long soi, neu tiep tuc tang nhiet o th lng hi tang dan khien iem 2 th toan bo hon hp long hoa hi hoan toan o la iem hi bao hoa kho, cac trang thaitrung gian trong iem 1 va 2 la trang thai trung gian co trang thai hi bao hoa amNeu goi Ml la khoi lng long trong hon hp th ng phan tram long tnh nh sau x=Ml/Mmix

Khi i t trai sang phai gian o pha ng phan tram long giam dan t 100% en 0%(toan hi)

Chnh xac hn khi co mat H2S, CO2 ( sour gas) th cac ap suat va nhiet o ti han phai c hieuchnh nh sau:Tc = Tc - T % H2S va CO2 tra ra o th ra Pc = (Pc*Tc)/(Tc+B(1-B))B la phan mole cua H2SA la phan mole cua H2S cong phan mole cua CO2

Co the tnh nh sau = 66,667(A0,9

A1,6

) + 8,333(B0,5

B4

) (o

K)


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Hnh 2.28: o th tra ap suat hi bao hoa cua kh hydrocacbon nhiet o thap


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Tsr = Ts/TcV du : tnh Pbh cua cac cau t T=50oC

Ts(K) Tc(K) Pc(kpa) Tsr Beta deva ln(Pbhqd) Pbh(kpa) Tr T(k) Ts(C)

C1 111.48 190.55 4604 0.58504 5.144602 1.099017 2.607919 62477.38 1.695 323 -161.5

C2 184.42 305.43 4880 0.6038 5.59954 1.132323 0.304213 6615.09 1.058 323 -88.58

C3 230.93 369.82 4249 0.62444 6.009085 1.152176 -0.88969 1745.44 0.873 323 -42.07

iC4 261.19 408.13 3648 0.63997 6.306419 1.160577 -1.7368 642.37 0.791 323 -11.81nC4 272.51 425.16 3797 0.64096 6.364656 1.16163 -2.12765 452.30 0.76 323 -0.49

iC5 300.84 460.39 3381 0.65345 6.627434 1.163968 -3.05271 159.69 0.702 323 27.84

nC5 309.06 469.6 3369 0.65813 6.76356 1.163625 -3.34174 119.19 0.688 323 36.06

C6 341.74 507.4 3012 0.67351 7.147244 1.156954 -4.5311 32.44 0.637 323 68.74

C7 371.42 540.2 2736 0.68756 7.532532 1.141778 -5.67495 9.39 0.598 323 98.42

nC8 398.67 568.4 2490 0.70139 7.943811 1.116205 -6.74072 2.94 0.568 323 125.67nC9 423.82 594.7 2280 0.71266 8.293207 1.086877 -7.7383 0.99 0.543 323 150.82nC10 447.16 617.7 2100 0.72391 8.673716 1.04699 -8.65027 0.37 0.523 323 174.16Bang cach tra o th ta cung co ket qua gan tng toi vi hon hp Pv = Pvi*xi

Khi hon hp long co nhiet o soi trung bnh (Tb) xac nh th ap suat hi bao hoa co the tra theoo th 2.30 sau:

Hnh 2.30: Ap suat hi bao hoa theo nhiet o khi biet TbHE SO KHONG ONG BO

W = - log(Pvp/Pc)-1Trong o Pvp la ap suat hi bao hoa TR = 0,7oi vi hon hp W=yiwiV du tnh wi cua cac cau t:Bang cach tra Pvp Tr = T/Tc =0,7 sau o tnh W = - log(Pvp/Pc) 1

Tc(K) Pc(kpa) Pvp(kpa) Tr T(k) f(Pvp)-w w

C1 190.55 4604 449.51 0.7 133 0.00 0.0104

C2 305.43 4880 389.51 0.7 214 0.00 0.0979

C3 369.82 4249 299.29 0.7 259 0.00 0.1522


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C16 283C17 300C18 313C19 325C20 338

Ngoai ra gia tr Tb con co the c lng nh sau:

Hoac theo cac cong thc cua CAVETT nh sau:

Tc: nhiet o ti han: (R)Pc: ap suat ti han (psia)Tb: nhiet o soi trung bnh (F)API: t trong API


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Hnh 2.31: T trong he hydrocacbon long theo nhiet o va ap suat


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Hnh 2.37: o th tra Enthanpy cua hydrocacbon long theo MW va T


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Hnh 2.41: o th tra Enthanpy cua kh hydrocacbon theo MW va T vi P=1400~2100kpa


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Hnh 3.2 : TVP theo nhiet o cua mot LPG va gasolines

Qua o th ta de dang xac nh ap suat hi thc TVP cua mot so san pham tieu bieu nh LPGs,gasolines tai nhng nhiet o thay oi. Qua o th ta cung c lng c ap suat lam viec canthiet e duy tr chat long can ton tr dang long khi nhiet o thay oi. Hay ta cung co the chuyenoi gia ap suat RVP va TVPTVP: la ap suat trong thung cha kn tai mot nhiet o va o pha kh va long can bang.RVP: la ap suat hi c xac nh bi phng phap ASTM D323 37,8oC


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Ton that trong thiet b cha dau do hoa hi nh hnh anh sau:

Ton that trong thiet b cha dau tho do hoa hico the tch co nh c lng nh sau:

Viec mat mat con dien ra khi bm chat long vao thung cha mc chat long dang len se ay hi HCra ngoai.


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Hydrate nhng tap hp chat co the ton tai ben vng di dang tinh the, chung la mot dangdung dch ran, trong o cac phan t nc dung moi nh cac lien ket hydro tao thanh khung hydrate,trong cac khoang cua khung nay cac phan t co kha nang tao hydrate nh metan, etan, propane,

isobutan, nit, H2S, CO2, se chiem cho. Cac hydrocacbon co phan t ln hn se khong co kha nangtao hydrate. Gas hydrate co cac ac tnh (bieu hien) ben ngoai giong nh nc a, do o co thelam tac ngen ng ong va cac thiet b.ieu kien thanh tao hydrate ch khi hoi u cac sau: Co nc t do, va co s tiep xuc gia kh va nc. ieu kien nhiet o nho hn nhiet o tao hydrate. Co thanh phan nh metan, etan, propane, isobutan, nit, H2S, CO2. Co s thay oi ap suat nh qua van giam ap. Co moi trng va u thi gian.

Phng phap o th: ay la phng phap thng dung e c oan s bo ban au.neu biet c ty trong kh cua hon hp kh ta co the xac nh c ieu kien P, T tao hydtare.

Hnh 5.1 o th tra nhanh ieu kien tao hydrate cua kh hydrocacbon theo ap suat va nhiet o: do Katz phat trien, phng phap nay s dung cho ieu kien ap suat

t 0 70 bar.Ngi ta thiet lap he so can bang kh ran Kv-s cho cac n chat co the tao hydrate (C1-C4, N2,CO2, H2S), Kv-s phu thuoc vao ap suat va nhiet o xac nh bang tra o th tat ca cac cau t khonghnh thanh hydrate co Kv-s=tai ieu kien P, T bat au tao hydrate :

yi:thanh phan mole cua cau t i


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Hnh 5.2 : o th tra hang so can bang kh ran cua Methane

Hnh 5.3: o th tra hang so can bang kh ran cua Ethane


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Hnh 5.4 o th tra hang so can bang kh ran cua Propane


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Hnh 5.5 : o th tra hang so can bang kh ran cua i-Butane


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Hnh 5.8 : o th d oan nhiet o tao hydrate 6,9 MPa


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Hnh 5.13 : o th d oan nhiet o tao hydrate 41,4 MPa


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Hnh 5.19: D oan ieu kien hnh thanh hydrate cho kh gian n co = 0,9V du: mot hon hp kh gas = 0,7 ap suat ban au 10000kpa (abs) qua JT van gian n con 3400kpa (abs) hoi nhiet o kh trc khi qua van toi thieu la bao nhieu e khong xay ra hydrate.Giai:Tra o th hnh 5.17 tren ( = 0,7) ta d oan nhiet o can toi thieu la 44oC

Sau khi ap dung cac phng phap d oan ieu kien thanh tao hydrate ta co the ve c ngcong hydrate FGH phan ben trai cua ng cong la phan co the hnh thanh hydrate. Do o khongnen van hanh che o cong nghe vung nay ma khong co cac bien phap s ly chong hydrate.

Hnh 5.20 : ng ac tnh tao hydrate cua kh gas


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SF he so an toan 1,1 en 1,2Thong so c ban cua mot so chat c che thong dung:

Methanol EGEthylene glycol

DEGDiethylene glycol

Khoi lng phan t, Mw 32 62 106

Ty trong kg/m

3

800 1110 1120V du:Hon hp kh t nhien lu lng 3.5x106 std m3/ngay, ra khoi may nen P=8000kpa, T= 40 oC, sauo c giam ap va lam lanh tai P=6500kpa, T= 5oC e tach hydrocarbon long c 60m3/106 stdm3. Tnh lng Methanol nong o XL =100% can thiet e tranh tao hydrate tai P=40bar, T= 5oCGiai:3. Tnh mW (kg) : khoi lng nc t do trong he thong

WH2O tai P= 8000kpa, T = 40oC = 1000kg/106 std m3WH2O tai PCOLT = 6500kpa, TCOLT = 5oCmW = F(A-B) = 3,5x(1000 160) = 2940kg H2O/d

4. Tnh dd = HFT - TCOLT = 17-5=12HFT nhiet o tao hydrate = 17oC

3. Tnh nong o chat c che ngi ta a xay dng cong thc thc nghiem sau:XR = d.Mw/(Ki + d.Mw) (100)

= 12x32x100/(1297+12x32) = 23%4. Tnh khoi lng chat c che c xac nh theo cong thc sau:

mI = mWXR/(XL-XR)= 2940x23/(100-23)=880kg/d

5. Phan Methanol boc hi b mat theo pha kh va long c xac nh theo:

mat trong pha long HCLIQ = 0,4x60x3,5=80kg/dmat trong pha kh HCVAP = C*F*XR = 17x3,5x23 = 1370 kg/dC = 17 tra hnh 6.26.mI_TOTAL =( mI WATER + mI HC LIQUID + mI VAPOR) SF

=(880+1370+80)1,1 = 2563kg/d


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Hnh 6.1 o th qui oi phan mole cua nc ra phan tram khoi lng methanol trong dung dch

Hnh 6.2 o th tra he so C


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Khi phan tch va thiet ke hau het cac he thong ieu khien c coi la cac phan t tuyen tnh, tc laphan t ieu khien cho tn hieu rat le thuan vi tn hieu vao. Tuy nhien co nhieu dang phi tuyenkhac nhau xuat hien trong cac phan t ieu khien nh : tre, khoang chet, bao hoa ma ac tnhcua no c the hien qua hnh:

Hnh: moi quan he gia tn hieu vao/ra (I/O) cua phan t ieu khien- a: tuyen tnh: la moi quan he gia tn hieu vao/ra (I/O) cua phan t ieu khien hoan toan la

mot ng thang- b: phi tuyen : co the thay the gan ung bang mot ng thang, ng nay at v tr sai so

be nhat.- c: Dai chet la mot day cac gia tr ma o tn hieu vao X khong lam thay oi tn hieu ra- d: Tre la tnh phi tuyen dan en gia tr tn hieu ra Y khong trung nhau khi tn hieu vao tang

hay giam.- e: Tre va chet the hien sai lech ln nhat cua tn hieu ra gii han tren va di

- f: Bao hoa la gii han cua mot day cac gia tr tn hieu ra Y. Mot phan t thc at en giihan bao hoa khi tn hieu vao thay oi tn hieu ra khong thay oi.

o khuyech ai cua bo phan ieu khien xac nh mot ac tnh quan trong cua he thong ieu khienla dang giam chan. ac tnh nay c he thong the hien ra nh la mot ap ng di tac ong cuaben ngoai. ap ng cua he thong ieu khien the hien theo nam dang nh sau


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Hnh: cac dang ap ng

Khi o khuyech ai tang ap ng cua he thong thay oi theo cac dang nh sau:a: qua giam chan, b: giam chan ti han, c: giam chan tat dan, d: ap ng bien o khong oi, e: apng bien o tang dan

Ba loai au ac trng cho he thong on nh, hai loai sau ac trng cho trang thai khong onnh. K thuat on nh c dung e lam tang o giam chan trong he thong, va do o cho phep atc o khuyech ai cao. Y tng chung la tm mot tn hieu chong lai s thay oi ai lng cieu khien. Tn hieu o la toc o thay oi ai lng c ieu khien. Nh ta biet ao ham cua motbien la toc o thay oi cua bien o va tn hieu lam on nh nay c coi nh ao ham cua ailng c ieu khien. o giam chan tang neu ao ham cua ai lng c ieu khien c tr rakhoi tn hieu sai lech trc khi vao c cau ieu khien. Mot tn hieu lam on nh khac la ao hamcua tn hieu sai lech, neu ai lng ieu chnh la mot hang, tn hieu nay bang gia tr am cua aoham ai lng c ieu khien. Giam chan tang neu ao ham o sai lech c cong vi tn hieusai lech trc khi vao c cau ieu khien.

Hnh : ap ng tai bac thang


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Lam giam toi a gia tr cua tn hieu sai lech, mot so he thong sai lech co the giam en 0, trong khicac he thong khac oi hoi sai lech dd e bu cho s thay oi cua phu tai. Trong ca hai trng hphe thong ieu khien can a tr so sai lech ve gia tr on nh, tr so khong thay oi.Muc tieu th hai la giam en mc toi thieu thi gian on nh t oMuc tieu th ba la giam en mc toi thieu sai lech dd sau khi at c trang thai on nh

Cho thay oi phu tai theo ham bac thang sau o quan sat o th neu bien o cua mot nh dngbang bien o cua nh dng trc no khi o dao ong la tat dan hoi tu tot:

Hnh: Suy giam bien o khi co tai bac thang

-


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Hnh: ac tnh I/O cua che o PIChe o PI la to hp cua che o P va I . ay khi thay oi tn hieu vao th ban au bo PI lam viecnh khau t le tc la tn hieu ra u t le vi sai lech , sau o che o I tao ra s thay oi bo xung tn hieu ra tc la lam cho no t le vi tch phan cua tn hieu sai lech. Toc o tch phan I la so aocua thi gian can thiet e che o I thch ng lai s thay oi cua tn hieu ra do che o P a en.Che o I co xu hng lam tang dao ong cua ai lng c ieu khien. o khuyech ai P canphai giam khi ket hp che o I. ieu nay lam giam kha nang cua bo ieu khien e ap ng sthay oi nhanh cua phu tai. Neu qua trnh co thi gian tre ln tn hieu sai lech khong ap ng kpthi sai lech hien co trong qua trnh, s tre nay se dan en qua hieu chnh, che o I tiep tuc lamthay oi tn hieu ra cua bo ieu khien sau khi o sai lech a giam en 0.Che o PI thng dung qua trnh co thay oi phu tai ln khi mot mnh che o P khong co khanang giam dao ong va che o I tao nen tac ong hieu chnh e triet tieu dao ong.

he so gii han cua ao ham

Che o ket hp nay cho phep giam xu hng dao ong va cho phep tang o khuyech ai t le. che o PD, khau P tao nen s thay oi cua tn hieu ra t le vi tn hieu sai lech, khau D tao nen sthay oi bo sung cua tn hieu ra t le vi van toc thay oi cua tn hieu sai lech ngan chan trc giatr mi cua tn hieu sai lech va thay oi tn hieu ra mot cach tng ng. Tac ong ngan nga trclam cho khau D rat hu dung trong ieu khien qua trnh co phu tai thay oi ot ngot

Khau I dung e triet tieu sai lech t le khi thay oi phu tai. Khau D giam dao ong va tac ongngan chan s thay oi tn hieu sai lech. V the PID c dung qua trnh co tai trong thay oi otngot, mc o thay oi ln .Cac bo PID thc te co chen he so gii han ao ham vao khau PD nen u se la


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Hai loai van thong dung la van trt va van xoayVan trt tieu bieu la van cau (globe valve), van xoay tieu bieu la van bm, van bi

Hnh 7.1 Van ieu khienTuy thuoc yeu cau cong nghe ma ngi ta dung van co au xa (plug) khac nhau, cho biet moi loaiau xa co kha nang cho moi chat i qua tuy hanh trnh tng oi cua van hnh 7.2; hnh 7.3

Hnh 7.2: Cac loai au xa cua van


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Hnh 7.3 : o m va lu lng cua van-ng ac tnh van

Chon van co kch c ung la rat quan trong, neu van qua nho no co the khong ap ng cyeu cau cho dong lu chat i qua, neu qua ln se lang ph va lam viec khong on nh.Moi van ieu khien eu co mot he so Cv khac nhau phu thuoc vao kch c va loai van ieu khien.e chon c ung van phai biet ieu kien dong chay thc te va phng phap tnh toan Cv yeucau.Cac cong thc e tnh kch thc van c chuan hoa bi ISA c s dung kha rong rai

khi P < Ps *FL2)

dong the tch

dong khoi lng:

khi P >= Ps *FL2)dong the tch

dong khoi lng


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khi P < P1 /2*FL2)dong the tch:

dong khoi lng:

khi P >= P1 /2*FL2)dong the tch:

dong khoi lng:

khi van kieu xoay c lap at gia hai au giam th ta phai dung CvRFp thay v CvR(trongbang )

Khi chat long co o nht cao tren 40cSt hay trong ieu kien lu lng thap th ta phai hieu chnh Cvnh sau:


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Tom lai: khi ban tnh ra Cv, neu vt qua 80% CvR (gia tr nay trong ho s van khi no m 100%) thta nen chon loai van co kch c ln hn, ta cung khong nen chon van co Cv be hn 5% CvR van lapgia hai au giam th CVR = CVR Fpv du: chon van ieu khien cho hon hp dau tho C co cac tham so nh sau:

Giai:

gia s chon van cau 1 co CVR = 28 (t nhat bang 2 lan CVturbulent ) co FL = 0,9, Fd = 0,46

V du: Hay chon van cho ng hoi chnh tren gian nen kh trung tam (PCV6901) khi lu lng khla 40000 scmh ap suat trc van la 10000kpa, sau van la 5000kpa, nhiet o dong kh 40oCGiai:P1 = 10000kpa = 1450psiP2 = 50000kpa = 725 psiP = P1 - P2= 725psiT = 104oF= 564oRQ = 40000 scmh = 1412586 scfhG t trong kh 0,75Ta co FL2~ 0,98*0,98 = 0,96Cho nenP> FL2P1/2

khiP >= P1 /2*FL2)dong the tch:


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thay so CV= 1412586 (0,75x564)0,5/(834x0,9x1450)= 26,7Xem bang tai lieu do hang san xuat van cung cap ben di:Nen chon van 3 class 900co CvR = 34,4 , FL = 0,98 van m khoang 80% (co the chon van 4)CV thc te = 1412586 (0,75x564)0,5/(834x0,98x1450) = 24,5CV thc te / CvR = 71% chap nhan c.

Moi loai van dung cho chat long eu co he so van Cv do nha che tao cung cap he so nay tuy thuocv tr m cua van (% open), he so nay co lien quan en lu lng qua moi lien he:

q lu lng (m3/h)P chenh ap qua van (kpa) t trong chat long ieu kien nhiet o dong chay = L(T)/H2O = 1000V du : hay chon van e ieu khien cho bnh cha condensate lu lng trung bnh q=100m3/h,chenh ap khoang 690kpa, = 0,78Giai:Cv= (q/0,0865)(/P)0,5


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= (100/0,0865)(0,78/690)0,5= 38,8Nha san xuat cung cap ho s van

Cv @ % openBodysize

Travel10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

3 1 4,5 5,78 9,96 17,7 26,5 36,6 52,7 71,7 91,5 1074 1 8,26 13,5 19,9 30,9 44,1 72,5 113 152 182 203

Neu chon van 3 th van m khoang 62%, trong khi chon van 4 th o m khoang 46%

oi vi chat kh th ta dung thuat ng Cgva C1thay cho Cv, he so nay co lien quan en lu lngqua moi lien he:

m lu lng khoi lng (kg/h)P chenh ap qua van (kpa)1 t trong chat long ieu kien vao vanC1 (he so hoi phuc ap suat) = 25 oi vi van bm

= 28 oi vi van bi= 33->35 oi vi van cau

Trong cong thc tren sin[(3471/C1) (P/P1)]Degphan anh dong qua van la ti han khi[(3471/C1) (P/P1)]Deg 90okhi o ta lay [(3471/C1) (P/P1)]Deg= 90oe tnh toan


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ay la dang van an toan co cau tao n gian nhat, thng c s dung khi xa kh va hethong khong co ap suat hoac ra moi trng.

V khong co c cau can bang nen s hoat ong cua van b anh hng rat ln cua ap suat hethong xa (ap suat ngc).

Khi ap suat he thong xa (ap suat ngc) ln hn 10% ap suat at van an toan, van dangkhong can bang khong c s dung.

S khac biet gia van can bang va khong can bang la cho van dang can bang c thietke them mot pitong hoac mot ong sinphong at pha tren a lam kn nham loai tr s tac ong cuaap suat ngc len a lam kn.

Hnh 8.1 Van an toan dang khong can bang


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Hnh 8.3 : Van an toan dang ieu khien pilot

w: lu lng khoi lng qua van kg/hB he so = 7,6x10-5C: he so phu thuoc vao t so nhiet dung rieng k= Cp/CvKo: hieu suat xa ap van do nha che tao van cung capA: tiet dien ca xa cua van mm2

P1 : ap suat trc van kpa(a)Mw: khoi lng phan t cua khZ : he so nen tai ieu kien lam viecT : nhiet o trc van oKAp suat P1 se lay bang ap suat at cong vi lng vt ap cho phep (trong trng hp thong

thng la 10% ap suat lam viec cho phep). Do o thong thng P = 1.1 Pset .Tiet dien co ch cua van xac nh t ch cai ky hieu qui c tren van sau o tra bang sau:

orifice Tiet dien mm2

D 71E 126,5

F 198,1G 324,6H 506,5J 830,3K 1186


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V du: tren van ky hieu 3 J 4 co ngha mat bch au vao 3, mat bch au ra 4, tiet dien coch cua van A= 830,30 mm2.He so C xac nh nh sau:

k C1 315

1,1 3271,16 3331,2 337

1,25 3421,3 347

1,35 3511,4 356

V du : xac nh lu lng qua van an toan co cac thong so sau:Kch c: 2 H 3. Ap suat at Pset= 2700 kpa. Vt ap cho phep 10%. T = 40oC, Mw = 22, Z = 0,92Giai:

A = 506.5 mm2.P = 1.1 x 2700 = 2970 kpa = Mw/Mwair = 22/29 = 0,76k = 1,3 0,31(-0,55) = 1,3 0,31(0,76-0,55) = 1,2C = 337Ko= 0,97w =7,6 x 10-5337x0.97x506,5x2970x (22/(0.92x313))0,5w = 10392 kg/h


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ay la phng phap o lu lng kh hay dung nhat hien nayOrifice at vuong goc vi hng dong chaycac thiet b o kem theo : o ap suat trc orifice, o chenh ap trc va sau, o nhiet o

Hnh 9.1 Cau tao orificesau khi co cac thong tin t cac thiet b o ta co cong thc tnh toan nh sau:

Q m3/h Lu lng tnh ieu kien chuanhw mm H2O Chenh ap qua orificePfkpa(abs) Ap suat trc orificeFb He so orifice Tra bang 3-16, phu thuoc vao kch c orifice

va ng knh ong thong so nay e tra rang knh orifice

Fpb He so ap suat ieu kien chuan,

Fpb = 101.325/Pb = 1

Ap suat ieu kien chuan Pb=101.325 kpa

Ftf He so hieu chnh nhiet o so vinhiet o ieu kien chuan,Ftf= (288/(273 + TfoC))0.5

Nhiet o k chuan = 15oC.Tf= nhiet o dong kh

Fpv He so phu thuoc vao he so nen ZFpv = (1/Z)0.5

Fg He so phu thuoc vao ty trong : ty trong tng oi cua kh 15oC


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Fg = (1/)0.5Fr He so phu thuoc vao he so Reynold

(che o dong chay) = 1+ b/(hwPf)0,5b tra bang

Y He so gian n cua ong va orifice phuthuoc vao ap suat Y 1

Ftb He so nhiet o ieu kien chuan, Ftb =

1 oi vi nhiet o chuan bang 15o

CFa He so gian n nhiet cua orifice =1khi Tf0,67 0,15->0,7


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Hnh 9.2 : Bo o lu lng qua tam lo

o lu lng kieu turbine co ng dung rong rai, ngoai tr cho chat long co o nht cao, khi lamviec turbine se quay ma toc o quay phu thuoc vao lu lng va tnh chat cua moi chat qua no

Xac nh c toc o cua turbine la se xac nh c lu lng. Do o thiet b o lu lngbang turbine la thiet b o toc o quay cua turbine.

Moi vong quay se tng ng vi mot lu lng the tch, c xac nh bang he so turbine .

Hnh 9.3 : Bo o lu lng kieu turbine


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Hnh 9.5 : Bang tra he so Fb


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Hnh 9.6 : Bang tra he so b


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Hnh 9.7: Bang tra he so b


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cac toc o thap, cac phan t cua moi chat chuyen ong theo dong chay tng oi on nhva thang hang. Toc o cua dong chay at cc ai tam ng ong va gan nh bang 0 tai thanhong. Che o dong chay nay c goi la dong chay tang

Neu tang toc o dong chay ti mot mc o nao o, cac phan t trong dong chay bat auchuyen ong hon loan (khong con thang hang so vi phng dong chay). Che o dong chay nayc goi la dong chay roi.e xac nh che o dong chay, Reynold a a ra mot he so khong n v - he so Reynold Re

Re = dv/ = 4q/(d) = 4m/(d)d (m): ng knh trong cua ong.v (m/s) :van toc dong chay. (kg/m3): ty trong moi chat tai ieu kien dong chay. (kg/(m.s): o nht moi chat. (1cp=0,001kg/m.s)m (kg/s) : lu lng khoi lng

q(m3/s) : lu lng the tchS (m2) : thiet dien trong cua onggc he so chuyen oi khoi lng/lc = 1(kg.m/N.s2)g: gia toc trong trng = 9,81m/s2

P (Pa) : ap suatf: o nhamX (m) : hieu o cao (h2-h1)

Neu Re< 2000 : che o dong chay tang on nh, f=16/Re.Re> 4000 :che o dong chay roi, f=0,042Re0,194 (dung cho ong ln d>20cm, 8in) .Re> 4000 :che o dong chay roi, f=0,042Re0,172 (dung cho ong nho d Re > 2000 : Che o chuyen tiep, co the la on nh hoac roi.

Ton hao ap lc cua dong chay c chia thanh 3 thanh phan sau: Ton hao ap lc do ma sat Pf. Ton hao ap lc do thay oi the nang PX. PX (X)g/gc Ton hao ap lc do thay oi ong nang Pv. Pv (V2)/(2g)P = Pf+ PX + PvTrong he thong ng ong ong nhat, s thay oi toc o dong chay gan nh bang 0. Doo phan ton hao do ong nang Pv ~ 0. Thc te trong tnh toan ton hao ap lc, phan naythng khong ang ke va c bo qua.

Ton hao do thay oi the nang chnh la cot ap thuy tnh do thay oi o cao. Phan nay c

xac nh de dang, ty le vi thay oi o cao va ty trong. PX = (X)(g/gc).Phan ton hao ap lc do ma sat Pf la phan quan trong nhat. Phng trnh tong quat e xacnh ton hao ap lc do ma sat co dang nh sau:

L (m): chieu dai ongsau khi bo qua phan ton hao ap lc do thay oi ong nang ta co tong ton hao ap lc c

rut gon nh sau:


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V du: ng ong kh ve b t gian nen kh trung tam co cac thong so nh sau, hay tnh kha nangvan chuyen cua ng ong.

12500 6000 0.38 0.78 110000 318 303 298 308.82 9630.63 0.528521 0.9 8889068.6

cong thc Panhandle BLu y : tren ng ong co cac thiet b nh valve , co, cut, au noi tai ay ton hao ap lc do masat se ln hn do thay oi hng dong chay va thiet dien thu nho, thng c goi la ton hao cuc

bo. Thong thng ngi ta se qui oi cac thiet b tren thanh cac oan ong tng ng sau o congvao o dai thc te thanh o dai tng ng e tnh toan.

Bang sau hng dan qui oi cac thiet b ng ong thanh cac oan ong co ton hao tng ng.


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Hnh 10.1: Ton hao ap lc qui oi cua van, au noi.V du: tnh toan chieu dai qui oi oan ong sau e tnh ton hao ap lc:

Giai:T hnh 10.110 ball valve Le= 1,8 m


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10 90oS.R. el Le= 8,2m10 tee Le= 18mchieu dai qui oi la L = 5 + 1,8 + 15 + 8,2 + 2 + 18 +10 = 60me tnh kha nang van chuyen cua cac he thong ong mac song song hay noi tiep ta theo cong thcqui oi chieu dai va ng knh ong nh sau:Hai ong loai ln A va B mac song song se tng ng vi ong E theo phng trnh nh sau:D

e

2.661/Le

0.554

= D

A

2.661/LA

0.554

+ D

B

2.661/LB

0.554

Hai ong loai nho A va B mac song song se tng ng vi ong E theo phng trnh nh sau:De2.641/Le0.547 = DA2.641/LA0.547 + DB2.641/LB0.547V du: hai ong 10 va 12 mac song song 6km neu dung ong 14 th chieu dai tng ng la baonhieu:Giai:De2.661/Le0.554 = DA2.661/LA0.554 + DB2.661/LB0.554142.661/Le0.554 = 102.661/60.554 + 122.661/60.554ta c Le= 5,3 kmOng nho B se tng ng ong A theo phng trnh:DA = DB(LA/LB)0,207 hoac LA = LB(DA/DB)4,828

Ong ln B se tng ng ong A theo phng trnh:DA = DB(LA/LB)0,208 hoac LA = LB(DA/DB)4,806V du: ong B co D=200mm dai 2000m tng ng ong A co D=100mm theo chieu dai nh sau:LA = LB(DA/DB)4,828LA = 2000(100/200)4,828= 70,4m


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PRESSURE-TEMPERATURE RATINGSFOR STEEL PIPE FLANGES AND FLANGEDFITTINGS

CLASS 150 300 400 600 900 1500 2500

Hydrostatic test pressure psig 450 1125 1500 2225 3350 5575 9275temperature F max allowable non shock pressure psig

100 285 740 990 1480 2220 3705 6170200 260 675 900 1350 2025 3375 5625300 230 655 875 1315 1970 3280 5470400 200 635 845 1270 1900 3170 5280500 170 600 800 1200 1795 2995 4990600 140 550 730 1095 1640 2735 4560650 125 535 715 1075 1610 2685 4475

700 110 535 710 1065 1600 2665 4440750 95 505 670 1010 1510 2520 4200800 80 410 550 825 1235 2060 3430850 65 270 355 535 805 1340 2230900 50 170 230 345 515 860 1430950 35 105 140 205 310 515 860

1000 20 50 70 105 155 260 430

D = ng knh cua ong inchsP= ap suat lam viec psiS1= ng suat doc truc psi = PD/4tS1= ng suat chu vi psi = PD/2tt= o day cua ong inchsS c lay bang % cua cng o chu uon toi thieu (min yield strength)

A & B 23/8in(60,3mm) va ln hn 60%

X42 59/16in(141,3mm) va nho hn 60%

65/8in (168,3mm) va 85/8in (219,1mm) 75%

en

103/4in (273mm) va 185/8in (457mm) bao gom 85%


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X80** 20in (508mm) va ln hn 90%

A 330 205B 415 240

P: ap suat lam viec ln nhat cho phep (Psig) S:=15000 psig ng suat cua hau het vat lieu ong thong thng nhiet o -20 to 650 o FE = 1 hieu suat lien ket cho ong uc khong hanD= ng knh trong cua ong khong hant:= o day ong thap nhat, inches (0,875 times the nominal thichness)

t: o day toi thieu cua ong (in): P: ap suat ong (psig)S=15000 ng suat cho hau het cac loai ong co nhiet < 650 o FE hieu suat noi cua ong uc lienR ban knh trong cua ong

BANG TRA ORING KIEU R KHI BIET MAT BCH VA CLASSNPS CLASS 150 300 400 600 900 1500 25001/2 R11 R11 R11 R12 R133/4 R13 R13 R13 R14 R16

1 R15 R16 R16 R16 R16 R181 1/4 R17 R18 R18 R18 R18 R211 1/2 R19 R20 R20 R20 R20 R23

2 R22 R23 R23 R23 R24 R262 1/2 R25 R26 R26 R26 R27 R28

3 R29 R31 R31 R31 R31 R35 R323 1/2 R33 R34 R34 R34

4 R36 R37 R37 R37 R37 R39 R385 R40 R41 R41 R41 R41 R44 R42

6 R43 R45 R45 R45 R45 R46 R478 R48 R49 R49 R49 R49 R50 R5110 R52 R53 R53 R53 R53 R54 R5512 R56 R57 R57 R57 R57 R58 R6014 R59 R61 R61 R61 R62 R6316 R64 R65 R65 R65 R66 R67


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Hnh 11.3 : Ong va cac thong so ghi tren than


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Hnh 11.4 : au noi

Hnh 11.5: Mat Bch

Hnh 11.6: gaskets amiang (flat gaskets) va spiral woundCung nh Oring th tren spiral wound co in class va NPS do o khi biet mat bch vi class va NPSth chon spiral wound co cung class va NPS la c.


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Hnh 11.8 : Thiet b o mc chat long

Hnh 11.9: Tong hp


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THIET B PHAN LY KH LONG:Cac thiet b tach kh va dau la mot bo phan cua thiet b khai thac tren be mat c dung e tachcac san pham khai thac t cac gieng dau va kh thanh chat long va kh rieng biet. Cac thiet b nayc lap at tren san khai thac, ng ong phan phoi hay cac bon cha tao thanh mot bo phan

hoan chnh cua he thong khai thacCAC DANG BNH TACH:

Theo hnh dang cac bnh tach thng co cac hnh dang sau: Bnh tach ng, bnh tachngang, bnh tach hnh cau.

Theo so pha th co bnh tach hai pha, bnh tach ba pha.e chon c ung loai bnh tach phai da vao cac ng dung k thuat cung nh cac ch tieu

kinh te, u, nhc iem cua tng loai

Hnh 12.1: Bnh tach ngang va ng


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Hnh 12.2 : Man chan sng

CAU TAO BNH TACHTam chan loi vao e oi hng dong giup tach chat long theo nguyen tac va ap, trong lc.Man sng chan loi kh ra giup lien ket cac giot chat long nho b cuon theo dong kh thanh giot lnhn roi ri xuong ni cha chat long.

Thiet b o mc chat long e giam sat khi van hanh.Van an toan nham bao ve bnh tach khoi ap suat cao vt qua ap suat cho phep.Cac thiet b t ong khac.

Cac bnh tach thng bao gom 4 khu vcKhu vc 1: phan tach kh chu yeu , ni xay ra qua trnh tach chu yeu phan chat long t do

trong dong hon hp long kh.Phan 2: phan lang chat long.Phan 3: phan cha chat long.Phan 4: Phan bay cac giot chat long lien ket chung lai va ri xuong.

BNH TACH NG:

San pham vao bnh tach phai qua bo phan dan hng gay ra viec tach s bo bi ba tac ong ongthi: trong lc, ly tam, va cham. Kh c tach bay len pha tren, trong khi chat long ri xuong nicha, cac giot long nho c thu hoi nh man chan sngu iem: bnh tach ng co the ieu khien lng tng oi ln chat long ma khong b cuon theodong kh, no ieu khien mc tot hn. Thng dung cho nhng gieng co t le kh dau t thap entrung bnh. Bnh tach ng cung co the kiem soat cat, hat ran, khuynh hng chat long bay hi trlai c giam thieu v dien tch mat cat ngang be, ay cung la mot u iem v no chiem khonggian ngang be phu hp gian khai thac chat hep.Nhc iem: chi ph che tao, van chuyen en ni lap at cao. Khi hai bnh tach co cung cong suatth bnh tach ng thng co kch thc ln hn bnh tach ngang.BNH TACH NGANGLoai nay co the dang ong n hay ong kep.Trong bnh tach ong n san pham qua loi vao en tam chan tai ay cung dien ra qua trnh tach sbo, chat long ri xuong ni cha, ni kh ra cung co man chan sng.Trong bnh tach ong kep, ong tren hoat ong nh bnh tach trong khi ong di co chc nang ton trchat long. Kh di chuyen ong tren vi van toc cao hnu iem: bnh tach loai nay co the tach ba pha kh-dau-nc bnh tach ngang co dien tch tiep xucdau kh ln , cho phep kh thoat nhanh hn, v the no co the x ly the tch kh nhieu , tnh kinh te vahieu suat cao, chi ph che tao re, chi ph van chuyen thap hn so vi bnh tach ng. Chung cungthuan li hn cho viec lap at va bao hanh. Bnh tach ngang han che dong roi va tao bot. Vi cungmot cong suat cho trc bnh tach ngang nho hn va re hn bnh tach ng. Bnh tach ngang thng

dung cho nhng gieng co t le khdau (GOR) cao.Nhc iem: viec ieu khien mc la mot van e kho trong bnh tach ngang, khong gian giao ongmc b gii han. Viec lam sach gap kho khan va v the khong tien cho nhng gieng nhieu cat. Bnhtach ngang chiem khong gian ln tuy nhien co the giam thieu bang xep chong cac bnh tach.BNH TACH CAU


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Bnh tach cau c che tao e toi u cong dung cua nhng thiet b tach kh-long hien co. Mot thietb hng dong theo tiep tuyen vi vo bnh, chat long tach ra do b giam van toc ot ngot trong bnh,ni kh ra cung co man chan sng.u iem: bnh tach kieu nay chi ph khong cao, re hn so vi dang ng hay ngang. Loai hnh caucan oi, nho , gon, thch hp cho nhng gieng co GOR trung bnh.

NGUYEN LY TACHCo nhieu ky thuat khac nhau ng dung vao viec x ly tach dau-kh nhng co the xep vao hai loai:tach c hoc va tach hoa pham da tren nguyen tac can bang nhiet ong kh long. Bnh tach c hoctheo ba c che: tach nh trong lc, tach nh ly tam, tach nh va ap.

Hnh 12.3: Bnh tach cau tao va lam viecTHIET KE CHON LA BNH TACHXac nh o day thanh bnh:Cong thc c ban e xac nh o day bnh tach (ASME )oi vi phan than hnh tru:


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h/d Fg h/d Fg0 1 0,3 0,748

0,05 0,981 0,35 0,6880,1 0,948 0,4 0,626

0,15 0,906 0,45 0,5640,2 0,858 0,5 0,5

0,25 0,804 0,55 0,436

Lu y :

khi thiet ke nen laym: lu lng khoi lng (kg/h)g khoi lng rieng kh (kg/m3)qs lu lng the tch kh STD std m3/dPs ap suat std (kpa)P ap suat lam viec (kpa)T nhiet o lam viec (K)Ts nhiet o tieu chuan (K)Z he so nen @ P,TEdfhe so thiet ke 1,1 ~1,2

Cong thc xac nh kha nang cua bnh tach nh sau:

V du: tnh toan kch c cho bnh tach ng trung gian 1-V-252 tren gian nen kh trung tam. Lulng qs= 1,7x106std m3/d. l= 620kg/m3, g=38kg/m3 , = 0,76, MW = 22 ( solution 42 )

Giai:Lu y: lu lng the tch

M = 51060x1,7x0,76 = 65969 kg/hLay Edfhe so thiet ke = 1,1qa = Edfm/(3600g) = 1,1x65969/(3600x38) = 0,53m3/sv = Ks((l-g)/g)0.5= 0,07((620-38)/38)0,5= 0,274 m/sd = (4qa/(vFg))0.5 = [4x0,53/(3,14x0,274x1)]0,5= 1,57 m

LU LNG CHAT LONGLu lng chat long cua mot bnh tach phu thuoc vao phan the tch co ch cho chat long va thigian ma chat long lu lai trong bnhVL = qL(t)/1440VL the tch chat long trong bnh (m3)qL lu lng chat long (m3/d)t thi gian chat long lu lai (minutes)oi vi bnh tach ngang th


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oi vi bnh tach ng:

thi gian lu tru lay nh sau:Dau co phutDi 0,85 10,85 0,93 1-2

0,93 1 2-4Tach dau kh nc ap cao 2~5 phutTach dau kh nc ap thap 5~15 phut (nhiet o cang ln thi gian cang thap)

Thong thng ty le L/D nam trong khoang 3~8

S O CONG NGHE VA IEU KHIEN BNH TACH:

Hnh 12.4: S o cong nghe ieu khien bnh tach 3 pha


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Hnh 13.1: S o cong nghe he thong lam kho kh bang glycolNONG O TOI THIEU CUA GLYCOL SACH:Nong o cua glycol sach la yeu to anh hng manh nhat en iem sng cua kh gas no

cao hn ngay ca khi ban tang lu lng tuan hoan glycol. Trong thap tiep xuc (contactor) glycolsach ch tiep xuc vi kh gas tai mam tren cung con cac mam di nong o glycol a giam i doa hap thu nc do o trong thap tiep xuc iem sng thc te cua kh a lam kho se cao hn t 8 oC en 12oC so vi iem sng can bang. Thong thng lam kho kh bang glycol c thc hienen iem sng khong thap hn 25 oC en 35oC. Muon lam kho triet e th can dung dch glycolco o sach cang cao. e chon nong o yeu cau cua glycol sach e at c nhiet o iem sngyeu cau cua kh gas sau lam kho ta co o th 13.2

Hnh 13.2: o th tra nong o glycol sach yeu cau

Gia s nhiet o iem sng sau khi lam kho kh gas la 5 oC nhiet o thap tiep xuc la 46 oCe at c cac yeu nhiet o iem sng nay trong khi tra o th ta lay giam nhiet o iem sngxuong them 10 oC vay khi o nhiet o iem sng la 15 oC. Toa o cua iem sng can bang 15oC va nhiet o thap tiep xuc 46oC ri vao ng nong o glycol sach la 99.5%. ay chnh lanong o glycol sach yeu cau .

ng nong o t oan ng vi nong o 98.5% ay la gii han cua nong o glycol co thetai sinh 204 oC ap suat bnh tai sinh la ap suat ieu kien tieu chuan. Khi muon at nong o glycol

sau khi tai sinh ln hn th phai c tai sinh trong ieu kien ap suat chan khong (be hn 101 Kpa)hoac (va) co s tham gia cua kh stripping gas. C giam i 1 kpa trong bnh tai sinh th nong ophan tram khoi lng glycol sach tang them 0.014% Kh stripping gas nay phai la kh sach no ca vao thiet b tai sinh vi muc ch la lam giam ap suat hi nc tren be mat dung dch, thuc ays boc hi nc ra khoi dung dch . Trong thiet b tai sinh glycol nhiet o c duy tr trong khoang190 oC -204 oC neu 206.7 oC th TEG se b phan huy. Neu bnh tai sinh co ap suat thap 10 ->13


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e at c nhiet o iem sng can bang la -5 oC th trong tnh toan ta phai lay nhiet oiem sng tnh toan thap i them 10 oC khi o nhiet o iem sng tnh toan la -15oC. Tra oth 13.2 ng vi nhiet o iem sng -15 oC va nhiet o bnh contactor 40 oC ta tra ra nong oglycol sach yeu cau la Xgl = 99.2%

Lng nc bao hoa cua kh gas khi vao contactor (12500kpa, 40 oC) tra o th 4.1 W_inlet:700kg nc /1 trieu m3 kh gas

Lng nc bao hoa cua kh gas khi ra contactor (12500kpa, -5 oC) tra o th 4.1 W_outlet:60kg nc /1 trieu m3 kh gas

(W_inlet - W_outlet)/ W_inlet = (700-60)/700) = 0,914tra hnh 13.6 ra lu lng TEG tuan hoan la 0,031 m3TEG/kg H2Olng nc tach ra t dong kh la 3x(700-60)/24 = 80kg/hvay lng TEG sach tuan hoan la 31(liter)x80 = 2480 lit/he tra lu lng stripping gas ta dung o th 13.3 tra c 1 std m3 stripping gas/ m3 TEG x

2,48 = 2,48 std m3/hTnh toan kch c contactor:Van toc cho phep cua kh gas khi qua contactor:v= Ks[(L -g)/g]0,5

Ks = 0,055m/s neu contactor dung bublecaps= 0,09->0,105 contactor dung structured packing

L khoi lng rieng pha long vi he TEG-H2O th = 1120kg/m3g khoi lng rieng pha kh ieu kien contactor kg/m3rieng oi vi contactor dung structured packing th co the dung v= 3/(g)0,5

khi o ng knh toi thieu cua contactor lad = [4qact/(v)]0,5

d: ng knh contactor (m)qact lu lng kh thc te (m3/s)lu y:

qact = m/gqact = qstd PstdTactZact/(86400PactTstd)m (kg/s) lu lng khoi lng dong kh gasqstd (std m3/d) lu lng the tch dong khV du: TEG vao contactor e lam kho dong kh gas 1x106 std m3/d 40oC, 7000kpa, he so

nen cua kh la z=0,85, Mw = 19 tnh kch c contactor dung bublecaps, structured packingGiai:g = 7000x19/(0,85x8,314x313) = 60 kg/m3

v= Ks[(L-g)/g]0,5contactor dung bublecapsv= 0,055[(1120-60)60]0,5= 0,23 m/s

(Ks= 0,055m/s neu contactor dung bublecaps)qact= qstdPstdTactZact/(86400PactTstd)

= 1000000x101x313x0.85/(86400x7000x288)=0.154m3/sd = [4qact/(v)]0,5

= [4x0,154/(0,23x3,14)]0,5= 0,92mcontactor dung structured packing

(Ks= 0,09->0,105)


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v=0,095[(1120-60)60]0,5=0,39m/shoacv= 3/(g)0,5 = 3/600,5= 0,39d = [4qact/(v)]0,5= [4x0,154/(0,39x3,14)]0,5= 0,71m

Hnh 13.4: Structured Parking va Bubble cap


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Hnh 13.5: o th tra lu lng glycol sach (N = 1)

Hnh 13.6 : o th tra lu lng glycol sach (N = 1.5 )


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Hnh 13.8 o th tra lu lng glycol sach (N = 2.5)


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Hnh 14.1: S o cong nghe minh hoa cho cum lam kho kh bang chat hap phuVi he thong n gian nhat gom hai thap th mot thap hap phu nc con mot thap giai hap bangkh gas nhiet o cao, thap hap phu se lam viec cho en khi bao hao nc, thng th vao khoang8~24 gi. He thong lam kho kh bang chat hap phu thng phai chi ph nhieu hn khi mua cungnh khi van hanh hn he thong lam kho kh bang glycol, tuy nhien no lai hu hieu hn khi oi hoi

dewpoint that thap, khi s ly H2SChat hap phu c tai sinh bang cach thoi gas (hay kh tr) vao thap giai hap vi nhiet o len en230~320 oi vi molecule sieve, oi vi zeolite th nhiet o len en 316~370oCDIEN BIEN TRONG THAP HAP PHU:


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Hnh 14.2: cac vung trong thap hap phuKhi kh gas am i vao thap th ton tai ba vung trong cot hap phu: vung 1 la vung can bang trongvung nay chat hap phu a bao hoa nc, vung 2 (vung MTZ) la vung chuyen tiep b tren bao hoa100% con b di la 0%, vung 3 la vung hoat tnh hoan toan khong ngam nc. Khi b di cuaMTZ di chuyen en ay cua cot hap phu th qua trnh hap phu trong thap nay phai dng lai neukhong lng nc trong gas se gia tang.KHA NANG CUA CHAT HAP PHU:Kha nang hap phu nc cua chat hap phu c hieu la khoi lng nc b hap phu tren mot n vkhoi lng chat hap phu.Kha nang hap phu nc tnh: la kha nang hap phu nc cua chat hap phu mi trang thai tnh ( nofluid flow) (hnh 14.3)

Hnh:14.3: o th tra kha nang hap phu nc tnh cua chat hap phu khi con miKha nang hap phu nc ong: la kha nang hap phu nc cua chat hap phu mi trang thai ong(fluid flow) thng lay bang khoang 50~70% (Kha nang hap phu nc tnh)Kha nang hu ch: o la kha nang cua chat hap phu thc te con lai suy giam theo thi gian so viluc con mi (hnh 14.4 cho silica gel)


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Hnh 14.4: Kha nang hap phu hu ch sut giam theo thi gian cua Silica gelKha nang hu ch cua chat hap phu co the c lng nh sau:

x: Kha nang hu ch toi a cua chat hap phu (wt%)xs: Kha nang hap phu nc ong trong trang thai bao hoa (wt%) = 50~70%(Kha nang hap phu nctnh)hZ: chieu dai MTZhB: chieu dai cot hap phuKha nang hu ch (x) cua mot vai chat hap phu co the lay nh sau:

x (wt%)Nhom hoat tnh 5~12

Silica gel 5~8Molecular sieve (4A) 7~14

oi vi silica gel va nhom hoat tnh th xs con phu thuoc vao nhiet o, o th 14.5. Xac nh he sonhan hieu chnh cho xs


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Hnh14.5: o th tra he so nhan hieu chnh v nhiet o cho kha nang hap phu nc ong xscuasilicagel va nhom hoat tnh

oi vi molecular sieve khi nhiet o be hn 70oC th khong can phai hieu chnh xsChieu dai MTZ : chieu dai MTZ phu thuoc thanh phan kh, van toc kh, c hat hap phu, o am khRH, o sach cua cot hap phu.Chieu dai MTZ co the c lng nh sau:

qstd lu lng kh 106std m3/dW lng nc bao hoa trong kh P,T kgRH o am tng oi cua kh %D ng knh thap hap phu mP ap suat kh kpaT nhiet o kh oKZ: he so nen khC he so tuy tng chat : silica gel C=1; nhom hoat tnh C=0,8; molecular sieve C=0,6THIET KE THAP HAP THUVi he thong gian n ch gom hai thap ch nen ap dung cho lu lng kh nho di 1,5 trieu m3

kh ngay, khi lu lng kh ln th co the dung he thong 3~4 thap. Thi gian tai sinh t r va thi gianhap thu lien he nh sau: tr = ta/(n-1) vi n la so thap. Nh vay so thap n phai phu hp e u thigian tai sinh. Neu kh bao hoa nc th mot chu k hap thu thng la 8~16 gi, neu kh a c lamkho bang glycol trc o th mot chu ky hap thu la khoang 24~30 giKch thc cua thap lien quan en van toc kh, sut giam ap suat cho phepPhng trnh Ergun cho ta o sut giam ap suat theo chieu dai nh sau:

P/L ap suat sut giam theo chieu dai (kpa/m) [thng vao khoang 7~10 kpa/m]P khong nen vt qua 70kpa. o nht kh (cp)

vg van toc kh be mat (m/s)g khoi lng rieng kh (kg/m3)B va C tuy theo hnh dang kch c hat hap thu nh sau

c lng nh sau A = 67 (hat cau 1/8)

A = 48 (hat cau 1/16)ng knh thap: qa lu lng thc te ap suat va nhiet o lam viec (m3/minus)

(m3/minus)khi ng knh thap a co th chieu cao cot hap thu tnh nh sau:

hB chieu cao cot hap thu (m)


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mw khoi lng nc b hap thu trong mot chu k (kg)x kha nang hap phu hu ch (%)B khoi lng rieng cua chat hap phu (kg/m3)d ng knh thap (m)Chieu cao cua thap hap phu se gom chieu cao cot hap phu cong vi chieu day cac thanh phan onnh va khoang khong can thiet (chieu cao them vao khoang 1~1,5m) xem hnh 14.6

Hnh 14.6: Cau tao cua mot thap hap phuTot nhat t so hB/d khoang 2,5~6

V du: Tnh toan s bo cho he thong lam kho kh bang molecular sieve c hat 1/8 biet lu lngkh qs= 1x106 std m3/d, T=30oC, P= 6000kpa, z=0.86,=0.65, =0.014cp, W=720kg/106 std m3, gias dung hai thap song song va 12 gi cho chu ky hap phu.


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Hnh14.7: S o cong nghe minh hoa cho cum lam kho kh bang chat hap phuGiai:g = P.Mw/(zRT) = 6000x0,65x28,97/(0,86x8,314x303) = 52,1 kg/m3A = 67 (hat cau 1/8)vg = A/g0,5 = 67/(52,1)0,5 = 9,3 m/minqa = (qs/1440)(Ps/P)(T/Ts)z (m3/minus) = (1000000/1440)(101,3/6000)(303/288)0,86 = 10,6 m3/minng knh thap: d= (4qa//vg)0,5 = (4x10,6/3,14/9,3)0,5 = 1,2 mLng nc b hap phu trong mot chu ky la:mw = (1x106 std m3/day)(12h/24h)(720kg/106std m3) = 360 kg H2O/chu kychieu cao cot hap thu tnh nh sau:

gia s x=10%hB = 400mw/(xBd2) = 400x360/(3,14x10x705x1,2x1,2) = 4,5 mt so hB/d = 4,5/1,2 = 3,8 OK!Kiem trao sut giam ap suat theo chieu dai nh sau:P/L = Bvg+Cgvg2 = (4,16)(0.014)(9,3)+(0,00135)(52,1)(9,3)2 = 6,6 kpa / m OK![thng vao khoang 7~10 kpa/m]P = 6,6x4,5 = 30 kpa khong nen vt qua 70kpa. OK!Chieu dai MTZ co the c lng nh sau:hZ= (C)0,115[qstd0,2389W0,7895RH0,5249/d0,4778][P/(Tz)]0,5506

=0,6x0,115[10,23897200,78951000,5249/1,20,4778][6000/(303x0,86)]0,5506 = 970 mmgia s Kha nang hap phu nc ong xs khoang 63% cua(Kha nang hap phu nc tnh)Kha nang hap phu nc tnh tra o th = 22 % do o xs = 0,63x22 = 14%Thay vao (x)=[ (xs)(hB)-0,45(xs)(hZ)]/ hB

= [14x4,5-0,45x14x0,97]/4,5 = 12,6 wt% tng ng x gia s 10 wt% vay kch thcthap at yeu cau lam viec.


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MAY BMNGUYEN LY VA PHAN LOAI BM:

Nguyen ly nay la tao ra mot the tch thay oi t nho en ln va ngc lai. Khi the tch bm tbang khong tang dan en gia tr ln nhat o la qua trnh nap lu chat. Khi the tch giam dan ve giatr khong la qua trnh nen ay lu chat. C mot chu ky hut ay bm van chuyen c mot the tchlu chat co nh. Trong qua trnh bm lam viec s thay oi trang thai cua lu the luon tuan theocong thc sau:

PV = const va PVk = const.P la ap suat lu chat, V la the tch, k = 1,4 he so.Cac loai bm ap dung nguyen ly nay la: bm piston, bm banh rang, bm truc vt,

Hnh 14.1: Mat cat bm ly tam nhieu tang canh

Nguyen ly nay dung trong thiet ke canh may bayDong chat long chuyen ong en canh va bao trum len canh, canh c at ngieng goc so vidong chat long nen pha tren lng canh tao nen cac xoay lu the chnh v vay ma dong lu the atac ong len canh mot lc nang R

Loai bm tieu bieu: bm canh nang (hay bm hng truc)


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Nguyen ly nay da tren nguyen tac bao toan nang lng cua dong lu the ngha la khi van toc tanglen th ap suat giam i hoac ngc lai, nh vay tai cho dong chay cua lu the co van toc ln otngotth ap suat se giam ta tao ra khong gian co ong thong vi ni can hut chat long th chat longay se b hut theo dong lu the v tai cho cuc bo nay ap suat thap. CAC THONG SO CHNH CUA BM:

Moi lien he gia o chenh ap suat P qua bm vi cot ap H xac nh nh sau: H = chieu cao cot ap thuy tnh, m;P = P2 - P1 lng ap gia tang qua bm kpaA he so = 9.81 = khoi lng rieng chat long ieu kien au ra Kg/m3

Power (kW) = A.(q)(P2- P1)/EA hang so he n v: = 1E: hieu suat cua bm phu thuoc loai bmq: lu lng the tch qua bm m3/s

NPSH (Net Positive Suction Head) tam goi la cot ap hut au vao la mot trong cac thong so

quan trong trong lap at va van hanh bm. Neu cot ap hut au vao bm nho so vi yeu cau th khibm lam viec hay say ra hien tng xam thc bm.Xam thc la s pha huy lien tuc cua lu chat oi vi be mat vat lieu bm, o la do cot ap

hut au vao hu ch NPSHA nho lam ap suat au vao bm giam xuong bang ap suat bay hi tngng vi nhiet o hien tai cua chat long. S bay hi manh liet cua chat long tao ra khoi lng botrat ln lien tuc tach ra khoi be mat vat lieu tiep xuc vi dong chay ong thi cac hat chat longkhong ngng lao vao e the cho cac bot kh tach ra nen va ap thuy lc rat ln lam ro va pha huykim loai.

e tranh ri vao vung hai pha va tach kh, ngi ta phai tao cho chat long mot lng apsuat bo sung bu cho s ton hao tren bang cach tao cot ap thuy tnh Hs gia bon cha va ni atbm nh hnh di


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NPSHA ( NPSH hu ch) se c tnh toan cu the nh sau:NPSHA = A(Ps - Pv - Pf)/ + Hs Hm - HacYeu cau : NPSHA> NPSHR

T cac thong so ac tnh cua bm ta se biet c o cao chong xam thc NPSHR (NPSHyeu cau : nha san xuat cung cap theo o th ac tnh khi bm lam viec), o cao cot ap thuy tnh Hsthc te phai ln gia tr tren.

Hnh 14.2: v du ng ac tnh lam viec cua bm ly tam

Thay oi ap suat bang cach ieu khien cai at ap suat au ra lam van ieu khien co oong m van ap ng nh hnh sau:

Thay oi toc o vong quay:


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Tuan hoan: trong mot so trng hp khi cong suat cua may bm ln hn so vi yeu cau taphai hoi mot phan chat long t au ra bm tr lai au vao bm e co lu lng au ra theo yeucau cong nghe.

Tuan hoan: hoi lu lng. Thay oi toc o vong quay truc. Thay oi quang chay cua piston.

Hnh 14.3 : Bm nhieu tang canh nam ngang hay thang ng


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Hnh 14.4 : Bm mot tang canhS O CONG NGHE IEU KHIEN BM:

Hnh 14.5 S o cong nghe ieu khien bm


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Thng phai dung cac may nen kh nham gia tang ap suat e van chuyen kh theo he thongong van chuyen. Mot ng dung na cua may nen kh la lam giam the tch kh giup thuan li choviec van chuyen kh bang tau hay ton tr , may nen kh co the tao ap suat rat cao e bm lng khtr lai va e duy tr ap suat va. Hai loai may nen kh thng dung trong cong nghiep kh la maynen ly tam va may nen piston, ngoai ra mot loai ac biet khac hay dung la thiet b hoa kh Ejector.MAY NEN KIEU PISTONLoai nay gom co piston di ong trong xilanh, chung co hai kieu: kieu hanh trnh n va hanh trnhkep. Ngoai piston va xilanh con co cac van xa, van hut, van hut se m khi ap suat trong xilanhgiam xuong thap hn ap suat kh dan vao, van xa se m khi ap suat trong xilanh bang hay cao hnap suat xa.MAY NEN KH LY TAMKieu may nen ly tam gom cac bo canh tron, bo canh nay co chong chong kieu toa tia kep gia haitam chan. Cac chong chong nay quay se tac ong vao kh lam tang ap suat kh nen.

Loai may nen nay cho dong lien tuc, ap suat xa t giai oan n la 100psig, lu lng dong caoen 100000sfmLoai nay thch hp vi qui trnh nen nhieu giai oan.EJECTOREjector gom co mot voi phun kh hay hi ong lc. Voi phun nay phun tia van toc cao qua buonghut vao bo khuyech tan co dang ong ventuari:

Hnh 17.1 : Ejecter

Kh nen c a vao nh mot voi phun khac trong buong hut. Hai dong t hai voi phun tao ra mothon hp co van toc cao, co ap suat cua kh ong lc. Bo khuyech tan (diffuser) ong vai tro nen

thong qua viec bien oi van toc hon hp thanh ap suat, lam cho van toc giam va ap suat tang doctheo chieu dai ejector. Nhiet o thay oi giong nh ap suat thay oi


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CHON LA MAY NENCo nhieu thong so can c xem xet khi chon la may nen tuy thuoc muc ch s dung.He thong nen kh nhieu giai oan co the dung nhieu may nen kieu khac nhau cho tng giai oan.Phan nay se tm hieu cac ieu lu y khi chon may nen kh o la:

Tnh chat kh chang han nh la t so nhiet dung rieng, tnh nen hay lng nc co trong kh khonganh hng en viec chon may nen kh, tuy nhien kh co t trong thap thch hp vi may nen kieu litam va co the can phai nen nhieu giai oan. Trong khi o khoi lng phan t, t trong hay mat okh khong anh hng en loai may nen kieu piston.

oi vi dong kh lu lng cao may nen li tam co the c dung cho cac giai oan nen au vamay nen piston cho cac giai oan nen sau cho ap suat cao hn. oi vi dong kh co lu lng tngoi thap, may nen piston co the dung trong moi giai oan nen.Khi dong kh co lu lng thay oi, may nen kh piston co the khong b giam hieu suat trong khimay nen li tam khong lam viec hieu qua di 50 en 90% cong suat toi a.

Dung may nen ly tam co ap suat nen va phai va t so nen thap, khi t so nen cao hn va ap suatcao hn nen dung may nen kh piston.S thay oi ap suat hut va ap suat xa la rat quan trong. oi vi loai may nen piston neu ap suatkh hut vao thap trong khi ap suat xa duy tr khong oi, cong suat toan bo cung b giam i, schenh ap cua toan bo cac giai oan tr giai oan cuoi cung b thap i, s chenh ap va gia tangnhiet o giai oan cuoi cung lai tang len. Neu ap suat hut gia tang phan hut giai oan mot, lulng toan bo he thong gia tang trong khi s chenh ap va nhiet o gia tang trong giai oan cuoi laigiam i.

Trong may nen ly tam ap suat hut tang th ap suat xa cung tang, neu ap suat hut giam th loai maynen nay khong nen en ap suat xa c.

May nen ly tam nen kem hieu qua nhiet o cao hay thap so vi may nen piston. Loai may nenpiston co gii han nhiet o nh nht, tuy nhien nhiet o xa phai gii han nhiet o thch hp etranh cracking dau nhn. Khong loai may nao khac phuc c van e nay do o can lam lanhtrung gian gia cac giai oan nen.

Nguon nang lng e chay thiet b dan ong may nen cung co tac ong en viec chon loai may

nen. Thong thng bo phan dan ong c chon da vao nguon nang lng co san, neu nanglng la ien th co the chay mot ien e dan ong may nen piston, con neu la kh th chay tuabinkh e dan ong may nen ly tam.

Cac may nen ly tam can dien tch mat san t hn va co o rung tng oi thap. Cac may nen khpiston thng sinh ra cac lc khong can bang lam rung san, thiet b


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Chi ph ban au cho may nen ly tam thng thap hn may nen kh piston, nhng hieu suat cua nothap nen cac chi ph s dung co the cao hn.CAU TAO VA LAM VIEC CUA MAY NEN KH LY TAM:

Hnh 17.2: Cau tao va lam viec cua may nen ly tamGhi chu: 1. Loi vao cua kh thap ap

2. ng dan va canh dan giup phan phoi gas eu khap trc khi vao tang canh autien

3. Tang canh au tien gan vi truc nen c quay vi van toc cao se lam tang vantoc gas lam gia tang ong nang, tang ap suat cho gas.

4. Sau o gas i vao bo khuyech tan (diffuser) van toc se giam va ap suat se tang5.

6.7.8.9.10.11. Loi ra cua kh gas co ap suat cao.


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CAU TAO VA LAM VIEC CUA MAY NEN KH PISTON:

Hnh 17.3 Cau tao may nen piston


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Hnh 17.4: Van hut may nen kh piston


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S dung moi tng quan ang entropy (tra o th hay tnh toan h) e tnh cong suat yeu cau:


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Wtheor = m(h2isen h1)m: lu lng gas qua may nen (kg/s)h2isen enthanpy au ra may nen kJ/kg (nam tren ng ang entropy s2 = s1)h1 enthanpy au vao may nen kJ/kgWact = Wtheor/EE la hieu suat may nenNgi ta co the giai bai toan nay qua o th lap san enthanpy va entropy hnh 17.6:

Hnh 17.6 : o th tra h va s theo P va T cua kh t nhienV du: mot may nen nen 1x106std m3/d, = 0,7, Z = 0,98 t P1=1Mpa, T1 = 300C len P2= 3Mpa.Tnh cong suat va nhiet o au ra, cho E(isentropic)=78% , E (total)= 75%


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Giai:T hnh 17.6 tai P1=1Mpa, T1 = 300C th h1 = 1000kJ/kmols1=s2 = -18,8kj/(kmol. K)Theo ng s2 va P2= 3Mpa th h2isen= 3800 kj/kmol, T2isen = 1000Cm= 1000000/23,64/24 = 1762 kmol/hWact= Wtheor/E = Wtheor= m(h2isen h1)/E = 1762(3800-1000)/3600/0,75= 1800kWh2

act= h1 + (h2

isen h1)/E = 1000 + (3800-1000)/0,78= 4600kj/kmol

Tai h2act= 4600 va P2 = 3Mpa T2isen = 1140C

hisen bien thien entanpy (kj/kg)T1 nhiet o au hut (oK)za he so nen trung bnh = (z1+z2)/2 co the dung hnh 17.7

Hnh 17.7: o th tra he so nen z theo P va T cua kh t nhien co khoang 0,65~0,75k so mu oan nhiet (so mu ang entropy) = Cp/Cv tnh nh sau:

Cpi nhiet dung mol (hnh 2.46, 2.47) hoac tra t bang sau:


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Ngoai ra kh thien nhien ta c lng k = 1,3 0,31(-0,55)Hoac khi biet Mw (lbm/lb-mole) va cP (BTU/lb-oF) ta tnh k = (Mw*cP)/( Mw*cP 1,986)

Hoac tra o th hnh 17.8 sau:

Hnh 17.8: o th tra k theo Mw va T cho kh hon hp hydrocacbonk ta tra nhiet o T la gia tr trung bnh au vao va au ra cua may nen kh.Nhiet o au ra may nen c lng nh sau :

Eisen la hieu suat ang entropy oi vi may nen kh ly tam vao khoang 0,65~0,8 oi vi may nenkh piston toc o cao vao khoang 0,7~0,75, vi may nen kh piston toc o thap vao khoang0,83~0,9. tuy nhien nha cung cap hay s dung hieu suat a hng (polytropic effeciency) hn laEisen la hieu suat ang entropy do o khi can chuyen oi th dung o th hnh 17.10 sau ay:


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Hnh 17.10 : Moi quan he gia Eisen va EpolyV du: theo v du tren:k = 1,3 0,31(-0,55) = 1,3 0,31(0,7-0,55) = 1,25hisen= T1zaR[(P2/P1)(k-1)/k - 1]k/(k-1)/Mw = 303x0,98x8,314[(3/1)0,2-1]x1,25/0,25/(0,7x28,97)

= 150 kj/kgm = (1000000/23,64)(0,7x28,97)/86400 = 9,93 kg/sW = 9,93x150/0,75 = 1986kWTd= T1{1+[(P2/P1)(k-1)/k-1]/Eisen}= 303[1+(30,2-1)/0,78] = 3980K = 1250C

A = 11,57 he so chuyen oiE: hieu suat tong the he thongQstdlu lng 106 std m3/dza = (z1+z2)/2v du : cung bai toan trenPower/stage (kW) = (A/E) [k/(k-1)]qstd{Ps/Ts}T1za[(P2/P1)(k-1)/k - 1]

=(11,57/0,75)(1.25/0.25)(1)(101.3/288)(303)[(3/1)0,2- 1](0,98) = 1980 kW

MOT SO THONG SO KHAC CHO MAY NEN LY TAM

Nang lng gia tang qua moi tang canh la : = u2/(2A)h (kj/kg) he so nang lng 0,8~1,1u toc o nh canh (m/s); umax vao khoang 250~300m/sA hang so 1000 J/kg


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oi vi may nen kh ly tam nhieu giai oan nen kh t nhien ~ 1, dung u = 275m/s th lng hgia tang qua moi tang canh la khoang 38 kJ/kge c lng ng knh banh cong tac nh sau:d = (q/0,05/u)0,5d: ng knh banh cong tac (m)q: lu lng kh au vao (m3/s)Toc o quay may nen co the tnh nh sau:N = 60u/d/N : rpmV du: Can mot may nen kh e nen 2,5x106scmd, kh t nhien co = 0,65, ap suat hut 1500kpa,ap suat xa 4500kpa, nhiet o kh vao 350C , Zavg = 0,95, hieu suat Eisen= 0,75, hay tnh:

Cot ap , cong suat, nhiet o au ra, so banh cong tac, ng knh banh cong tac, toc o trucquay.Giai:k = 1,3 0,31(-0,55) = 1,3 0,31(0,65-0,55) = 1,27(k-1)/k=0,2126Cot ap 308x0,95x8,314x[(4500/1500)0,2126

1}x1,27/0,27/0,65/29 = 160kJ/kg

= (11,57/0,75)(1,27/0,27)2,5(101,3/288)308x0,95[(4500/1500)0,27/1,27-1] = 4912kWnhiet o au ra: Td= T1{1+[(P2/P1)(k-1)k-1]/Eisen}

=308[1+(30,27/1,271)/0,75]= 416oK = 143oCso banh cong tac la 160/38 ~ 5lu lng: q = (2,5x106/86400)(101/1500)(308/288) = 1,98 m3/s

d = (q/0,05/u)0,5= (1,98/0,05/275)0,5= 0,38 mN = 60u/d/

= 60x275/0,38/3,14 = 13785rpmIEU KHIEN LU LNG CHO MAY NEN KH LY TAMieu hien nhien la neu ap suat hut, ap suat xa cung nh lu lng kh en may nen khong thayoi th khong can ieu khien lu lng may nen. Nhng thc te luon co s thay oi cac thong sonen can phai ieu khien lu lng.Cac thong so thay oi o la:

ieu kien hut: nhiet o, ap suat, lu lng.ieu kien xa: nhiet o, ap suat, lu lng.T so nen: ap suat xa tuyet oi / ap suat hut tuyet oi.Khoi lng rieng kh: oi vi may nen kh ly tam ap suat tang len khi kh co khoi lng

rieng tang len, ieu nay lai khong anh hng g vi may nen piston.

IEU KHIEN LU LNG CHO MAY NEN N (khong thay oi toc o phan dan ong)Trong trng hp nay lu lng co the c ieu chnh nh thay oi t so nen, hay tuan

hoan mot phan kh au ra may nen ngc tr ve au vao may nen.Co hai cach pho bien e thay oi t so nen:-ieu chnh kh xa ra-ieu chnh kh hut vao


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Ca hai phng phap nay c ieu khien bi thiet b ieu khien noi vi ng ong hut, thiet b nayluon nhan biet ap suat hut. Khi co s giam lu lng kh vao may nen ap suat hut giam, thiet bieu khien biet c o sut giam ap suat lien gi tn hieu en van ieu chnh lu lng ng xalam no ong bt lai tam thi, ieu nay lam ap suat xa tang len cung la tang t so nen len va lamgiam lu lng may nen phu hp vi trang thai lam viec mi. Ngc lai khi ap suat au hut tangtng ng lu lng vao may tang len, thiet b ieu khien lenh m them van ieu chnh lulng au ra lam tang them lu lng, giam ap suat hut, giam t so nen.S o ieu khien nh sau:

Thiet b ieu khien ap suat hut cung con c dung e ieu chnh van ieu khien lu lng attren ng ong hut (au vao may nen kh) nh s o cong nghe sau:

Hoat ong cua thiet b ieu khien van nh sau: khi lu lng kh tang, ap suat hut tang, thiet bieu khien lap tc ra lenh cho van tiet lu ong bt lai. khi lu lng kh giam, ap suat hut giam,thiet b ieu khien lap tc ra lenh cho van tiet lu m ln hn.


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Thiet b ieu khien ap suat hut cung con c dung e ieu khien van lap tren ng vong nh so

Khi lu lng kh giam, ap suat hut giam, thiet b ieu khien lap tc ra lenh cho van tiet lu m

ln hn e gia tang lu lng kh bang cach a mot phan lu lng au ra tr lai au vao maynen.IEU KHIEN LU LNG NH THAY OI TOC O PHAN DAN ONGToc o phan dan ong thng c ieu chnh e gi cho ap suat hut khong thay oi nh s osau:

Neu lu lng en may gia tang, ap suat hut tang, thiet b ieu khien ap suat hut truyen tn hieulam tang toc o phan dan ong, hay ngc lai thiet b ieu khien toc o se quyet nh giam toc o.Toc o thay oi phai phu hp vi gii han toc o cua may nen. Khi phan dan ong la Turbine khth toc o dan ong tang hay giam tuy theo lng gas nhien lieu cung cap vao.


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Hnh 17.11: May nen ly tam co phan dan ong la turbine kh

Hnh 17.12: ng ac tnh lam viec cua may nen kh ly tam.OI VI MAY NEN PISTON

: ap suat au vao c duy tr bang viec hoi lai mot phan kh au ra velai au vao cach nay kha n gian song khong kinh te va lam nhiet o kh vao may nen tang cao.

: la c cau kiem soat s ong m cua cac van hut trong cac xilanh. Khilu lng (ap suat) t i th mot hay nhieu van hut se b lam kenh (luon m) ieu nay khien cho


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kh vao xilanh bao nhieu lai b ay ra ve khoang hut bay nhieu. Cac van tai thng c ieukhien t ong phu thuoc vao ap suat hoac lu lng. Qua trnh thay oi tai may nen dien ra theotng bac (0%, 50%, 75%, 100%) tng ng vi (0%, 50%, 75%, 100%) so van tai lam viec.

cua truc may (oi vi phan dan ong la ong c ot tronghay turbine kh th de ieu chnh toc o hn la ong c ien)CHU TRNH LAM VIEC CUA MAY NEN KH PISTON:


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PHAN 18TURBINE KH

TURBINE KH

Turbine kh la mot loai ong c nhiet, bien nhiet nang thanh c nang. Theo ng dung cua chutrnh nhiet ong (Brayton).

he thong turbine kh gom ba bo phan chnh sau ay:May nen khong kh dung e nen dong khong kh len ap suat cao cung cap Oxy cho qua trnh

ot chay nhien lieu trong buong ot.Buong ot la ni ot chay nhien lieu tao nen san pham chay co ap suat va nhiet o rat cao.Turbine kh: ay la ni ma san pham chay t buong ot vao ong tang toc cua turbine (canh

tnh gan tren than turbine), qua ong tang toc nhiet o va ap suat dong kh giam xuong, toc o vaong nang dong kh tang len, sau o dong kh c thoi vao he thong canh gan tren a quay cuaturbine (canh ong) ay ong nang cua dong kh bien oi thanh c nang va lam quay truc turbine.


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Hnh 18.1: Chu trnh chuyen oi nang lng cua ong c turbine

Khong kh c may nen cua turbine hut va nen len ap suat co the ti 30 bar (tuy loai) e phucvu cho viec ot chay hi nhien lieu, lam mat, ieu khien va lam kn. Tren o th hnh 18.2, quatrnh nay c bieu dien bang ng 1-2.

Kh nhien lieu c hoa tron eu bi lng khong kh nap c tnh toan theo che o hoat ong

cua ong c vi lng nhien lieu c phun vao theo ty le nhat nh roi ot chay trong buong otcua turbine. ay la qua trnh chay ang ap. Tren o th hnh 18.2, qua trnh nay c bieu dienbang ng 2-3.

Hon hp kh chay gian n qua cac canh hng dong (giong nh cac mieng phun - xem hnh

18.3) roi qua cac tang canh cua turbine lc. Trong qua trnh gian n van toc dong hon hp kh keotheo ong nang dong kh tang len. Khi tac ong len be mat cua cac canh turbine ong nang nay sechuyen hoa thanh c nang (cu the la mo men quay). Tren o th hnh 18.2, qua trnh nay tng ngvi ng 3-4.

Hon hp kh chay sau khi a gian n qua cac tang canh cua turbine theo ong xa i ra ngoai.

Tng ng vi ng 4-1 tren hnh 18.2.

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