n?A4.44?=32.12根?dl0.022?2??
化学反应器
1?n?3?3n?1h kC?浓度 0、k的单位: k?kmolm??1?nkmol?时间?,浓度=m?3
?10级反应:
kC?kmol03??k?浓度(时间)?1?S?1 mh 1级反应:C?1?1?1m3?kmol??1kC??浓度?(时间)??3?S?1?nk?PS kmol.Sm??Pa2级反应:
0级反应:kP?Pa/S 1级反应:kP?S 2级反应:kP?PaS?1?1?1
r?浓度kmol=时间m3S
nAkmolN32?r?kpp对于气相反应,A,?rA的单位=mS,pA的单位=m,
kmol3?rAmS?kmolkp?n?.N?n.m2n?3.S?12pA?N??2??m?kp的单位=
kp与kc的关系:
nkcC?kppnnC?,p=CRT,∴
pRT
?p?nkC??nn??kppkp?kC?RT?kC?kp?RT??RT?,,或
1、化学计量式:A?2B?2Z
t=0时,nA0=0.14,nB0=0.2,nZ0=0.08,t=t时,nA=0.08,
xA?nA0?nA0.14?0.08??0.43nA00.14
nA0xA0.14?0.43?0.06mol1
∴,nB=nB0-nA0×xA=0.2-0.14×0.43=0.14
??nZ=nZ0+nA0×xA=0.08+0.14×0.43=0.14反应进度:
?A??B?反应进行完全时的反应进度:
nB0xB?B?0.2?1.0?0.1mol2 kp??rAPa/S11???2PaSPa.h pAPa22、(1)、速率常数kp=3.66 其单位为,
rA??(2)、
1dnA(mol)mol?3V(m3)dt(h)m.h
mol3rAm3m.hk?2??2mol.hCA?mol??3??m?
对于理想气体,pA?nART,
pA?nART?CARTV,
?dpAd?CART?dCA222?3.66pA??3.66?CART???3.66RTCAdtdtdt 变为 ,∴
∴
?1??m3?atm?101325pakc?3.66??0.08206??400K???p?hrkmol?K1atm???a??m37??1.217?10??kmol?hr??E/R(?)r923A0e?E/923R773923??er773A0e?E/773R11
4、?e?75000/8.314??0.0002?e1.804?6倍
111(?)kCACA0
t?6、对于二级反应,
t1?1?11?1?11????116.5St2????117.4S??0.85?0.011?0.85?0.015?,
讨论:对于二级反应,若要求CA很低时,虽然初始浓度相差甚大,但所需要的反应时间却相差甚微。这是因为反应时间主要消耗在反应的后期。 当?rA?0.05CA时,计算方法同上,
2t1?1?11?1?11????1980St2????1996S??0.05?0.011?0.05?0.015?,
停留时间分布
t? 1、
1111ln?ln?119mink1?xA0.01931?0.9
CA0?750kmol?1.75374?4.97?60?1m
2、同第七章6题 3、
(分子量:醋酸=60,丁醇=74,醋酸丁酯=116)
FA0FA01.724m32400kmolv???0.985??1.724C1.75h 24?116?0.5h,A0?t?t???34.5?30?3VR?v??0.985????1.058m?60??60?VT?VR/??1.058/0.85?1.245m3
VR?4、(1)、
qVxAfkCA0(1?xAf)qVxAf??0.171?0.8?1.447m3360?1.97?10?4?0.2
VR?(2)、
kCA0(1?xAf)qVxAfkCA0(1?xAf)0.171?0.93?3.255m60?1.97?103?4?0.1 0.171?0.8?0.723m3360?1.97?10?8?0.2
VR?(3)、
?t?另解:
11,t?VR,?VR?CA0CA0 与(1)相比,C增大1倍,∴V减小1倍,
A0R
∴VR=1.447/2=0.723M3
VR?5、
qVxAfkCA0(1?xAf)L??0.684?0.8?4.1m360?0.00278?4?0.2
PFR的长度:
VR4.1??334.3mA0.785?0.1252
VR?6、
qVxAfkCA0(1?xAf)?0.684?0.8?1.72m360?0.006633?4?0.2
L?VR1.72??146.7m2A0.785?0.125
t?7、(1)、
xA0.51??kCA0(1?xA)2kCA0?0.520.5kCA0
VR=qVt,VR2=6VR,6VR=6qVt=qVt2
6qVqVx?A?22??0.5kCA0kCA0(1?x?A),x?A?25xA?12?0 ∴,xA?0.75 6VRx?VR0.5A??22?qqkC(1?x)kC(1?0.5)VVA0AA0另解:(a) (b)
12?(a)/(b),
x?A2(1?x?A),∴x?A?0.75
(2)、对于PFR由于体积相同,其他条件不变,所以t3=t1,kt3CA0=kt2CA0=2
因为流动情况不同,根据PFR的特点,有以下关系式,
CA3t3??CA0?dCA1?11???2k?kCA?CA3CA0?CA0?ktC??1?2?3A0C?,A3
CA31C12?xA3?1?A3?1??C3,∴CA033 ∴A08、 2A+B→R, 可写成,A + 1/2B → 1/2RxA=0时 CA0 CB0 CR0=0 xA=0.6时 CA=CA0(1-xA) CB=CB0-1/2CA0xA
VR?qVCA0xA0.028/60?603??0.146m22kCA0.0025?2(1?0.6)2?(3?0.5?2?0.6)0(1?xA)(CB0?0.5CA0xA)14.4?0.8qVCA0xAVR??24?60?0.496m3kCA0(1?xA)0.0806(1?0.8)9、(1)、
qVCA0xAkCA0(1?xA),
VR?(2)、
xA?VRk0.496?0.38??0.9514.4qV?VRk?0.496?0.3824?60
VR?(3)、
qVCA0xA0.01?0.9??1.117m3kCA0(1?xA)0.0806(1?0.9)
qV10.011ln?ln?0.2m3k1?xA0.08061?0.8
VR1?(4)、
1?xA2?(5)、
111?k??1?xA2(1?k?)2,
,
??1????????1?x?1??k??1?0.9?1??0.0806?26.8minA2?????1
VR?qV??0.01?26.8?0.268m3 总容积:0.268×2=0.536m3
10、(1)、
CA0?750kmol?1.75374?4.97?60?1m
FA0FA01.724m32400kmolqV???0.985??1.724CA01.75h 24?116?0.5h,
xA0.5??33min?60?0.55h?3kCA0(1?xA)17.4?10?1.75?0.5
t?VR?qV(0.00?0.5)?0.985?1.05?1.034m3
VR?(2)、
qVxA0.985?0.5??0.539m3kCA0(1?xA)60?0.0174?1.75(1?0.5) qVxA0.985?0.5??1.078m322kCA0(1?xA)60?0.0174?1.75(1?0.5) qVCA0xA10.985?0.3233??0.38m22kCA60?0.0174?1.75(1?0.323)20(1?xA1)
VR?(3)、
VR1?(4)、
VR2?qVCA0(xA2?xA1)0.985?(0.5?0.323)3??0.38m22kCA60?0.0174?1.75(1?0.5)20(1?xA2)
反应器的总容积VR=VR1+VR2=0.38+0.38=0.76m3 计算结果说明,
VCSTR>VBTR>Vn-CSTR>VPFR
CA1?11、(1)、
CA0CA0??1?k1t1?k1VR/qV4.51?0.0567?0.80.1?3.1kmolm3
CA2?CA013.1kmol???1.8831?k1t1?k2t1?0.0806?8m CA0111.88kmol????0.8331?k1t1?k2t1?k3t1?0.158?8m CA01110.83kmol?????0.20531?k1t1?k2t1?k3t1?k4t1?0.38?8m CAN?CA0CA3?CA4?(2)、
?1?kt?N?1?kt?N,
?CA0CNln?1?kt??lnA0CAN,CAN
4.53.0890.205N???6.2ln?1?0.0806?8?0.498
ln为保证最终出口浓度≤0.205kmol/m3,应需7个反应釜串联。
VRCB0xBV(?r)?qV?RBq?rB,CB0xB 12、VqV?VR(?rB)VRk1?CA0?CB0xB?CB0?1?xB??CB0xBCB0xB0.12?0.2?1.4?0.8?0.75??1?0.75?m3??0.00640.75min
qVA?qVBqV0.0064m3???0.003222min
VSxA?qkS(1?xA) ,V13、
VP11?lnqVkp1?xAVP?VP与VS的关系:
kSkPVS(1?xA)lnxA11?xA
11xA?lnk(1?xA)kp1?xA
若VP=VS,则,SkS?∴,
xAkP1(1?xA)ln1?xA?0.6kP1(1?0.6)ln1?0.6?1.64kP 求反应温度,
?ERT2?ERT1A??E/RT∵,k?Ae
kPe?ERT1?kSe?ERT2,kS=1.64kP,∴,e?1.64e
?E?E?83740?ln1.64??0.495???23.3RT2RT18.314?423
T2?∴,
?83740?432K8.314?(?23.3)