Chinese J . Chem. Chem. Eng ., ., 14(5) 676—684 (2006)
Development and Commercial Application of Methyl-ethyl-ketone Production Technology a,b b, b b LIU Zhenhua(刘振华) , HUO Wenzhou (霍稳周) *, MA Hao (马皓) and QIAO Kai (乔凯) a
b
Dalian University of Technology, Dalian 116024, China Fushun Research Institute of Petroleum & Petrochemicals, Fushun 113001, China
Abstract A synthetic technology for the production of methyl-ethyl-ketone (MEK) is introduced, which makes use of butylene catalytic hydration to produce secondary butanol (SBA) and this is followed by dehydrogenation of SBA. By optimizing the operating conditions of a commercial unit, the running results showed that the recommended process was successful and that the catalysts had high activity, good selectivity, and long lifespan, which ensured long-term running in commercial units. Keywords methyl-ethyl-ketone (MEK), secondary butanol, hydration, dehydrogenation, resin catalyst
1
INTRODUCTION Methyl-ethyl-ketone (MEK) is an organic solvent that is characterized by satisfactory boiling point, good solubility, volatilization, and stability and is nontoxic. It is widely used as a solvent in paint, dye, pharmaceutical, pharmaceutical, and refining industries. MEK is also as an important raw material for organic chemical industries and is used for the production of MEK peroxide and oxime, as an intermediate in the perfumery in[1,2] dustry, as an antioxidant, and for catalyst production . With its expanding application in various industries, the producing capacity of MEK has shown an average annual increase of 5%–10% in many countries. Before 2001, there were only two MEK-production sites in China, both licensed by Deutsche Texaco Manufacture Technique, and the annual output was only about －1 20kt·a , which was far from satisfying the demand of －1 the domestic market and therefore at least 100kt·a MEK had to be imported. In 2004, the capacity was －1 －1 increased to 185kt·a , and the output was 110kt·a . By 2007, it is predicted that the demand for MEK －1 [3] would be 230—240kt·a in China . Currently, MEK is commercially produced using the two-step n-butylene technique: hydrating butylene to produce secondary butyl alcohol (SBA) and then dehydrogenating the SBA. Based on different catalysts, there were three main processes: vitriol indirect hydration, resin direct hydration, and motley acid direct hydration. Because of huge energy consumption; high cost of investment; serious equipment cauterization; and complicated treatment procedures for the exhaust gas, wastewater, and waste residue, the use of vitriol indirect hydration process declined gradually. In the case of the motley acid hydration process, the investment is too high and the operating condition is too rigorous; therefore, this process process is not the best choice. choice. On the
other hand, the resin direct hydration process is in general considered a better choice because the investment is relatively low and the reaction efficiency is comparatively high. There are two ways to produce MEK via via dehydrogenation of butyl alcohol: gas dehydrogenation and liquid dehydrogenation. Gas dehydrogenation is widely used in the industry because it involves a simpler process flow sheet and the investment is low. The key to technical development is the improvisation of the cata[4―8] lyst activity, selectivity, and operation cycle . In China, a large amount of n-butylene exists in liquefied gas and is mostly used as fuel. MEK has to be imported from other countries. From the point of view of resource conservation, the C 4 resource will certainly be used for producing MEK from n-butylene in the near future in China. After a thorough investigation of the entire technology of n-butylene direct hydration and dehydrogenation, Fushun Research Institute of Petroleum & Petrochemicals (FRIPP) developed high-performance, high-performance, heat-resistant catalysts for the hydration of butylene and the FDH-type specialty catalyst for the dehydrogenation of SBA. On the basis of these, the operating conditions, such as reaction process parameters, dynamics, and thermal stability, were optimized. Under the optimized operating conditions and with the use of specialty catalysts, the butylene per pass conversion was more than 8%, the selectivity of SBA was more than 98%, the conversion of SBA was greater than 85%, and the selectivity of MEK was more than 96%; all these techniques have been patented. Compared with the other licensers, FRIPP’s technology is characterized by the following features: ● Hydration reaction adopts low LHSV and high water/butylenes ratio; therefore, less amount of recycled butylene is required and energy con-
Received 2005-09-10, accepted 2006-04-17. * To whom correspondence should be addressed. E-mail:
[email protected]
Development and Commercial Application of MEK Production Technology
●
●
●
sumption is low; To recycle water, azeotropic distillation column is used in this process; The conversion is improved by lowering the SBA concentration in recycled water through the SBA-recovery technique; Pollution is well controlled by lowering the concentration of organics in the discharged water through the recycling of water.
2 EXPERIMENTAL 2.1 Test method and process flow From the flow chart shown in Fig.1, it can be seen that n-butylene and deionized water were pumped into the bottom of hydration reactor, where the hydration reaction took place. The SBA thus produced was discharged from the top of the reactor into the phase-separator. The SBA and unconverted hydrocarbons were separated from the water to form the upper layer, which then entered the di stillation column, where unconverted hydrocarbon was separated from the SBA. The unconverted hydrocarbon was at the top of the column, whereas the SBA was at the bottom of the column. The resultant SBA then entered the intermittent distillation column, wherein it was separated——light distillates were at the top of the column, heavy distillates were at the bottom, and the SBA product was in the middle. The SBA product then entered into a vaporizer to boil-off and was then introduced from the top of the vaporizer into the dehydrogenation reactor. The resultant MEK, from the bottom of the dehydrogenation reactor, was cooled inside a condenser and then moved into a phase-separator, wherein the hydrogen was separated at the top and the MEK product was obtained at the bottom. The wastewater containing alcohols discharged from the bottom of the phase-separator entered the flash tower where it was distilled. The azeotropic SBA mixture from the top of the flash tower entered the intermittent distillation column. The water discharged from the bottom of the flash tower was treated by both anion exchange column and ion exchange column, and [9,10] was recycled .
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Figure 1 shows the procedure for the commercial production of MEK from a 2L pilot plant reactor, the －1 capacity was 20kt·a , which was scaled up; the structure and dimension are as follows. 2.1.1 Hydration reactor Figure 2 shows the diagram of hydration reactor, which is a cylinder. The feed hydrocarbon was pumped from the bottom of the hydration reactor, this in turn moved upward through the column beds, reacted with the deionized water, and, finally, the end product was discharged from the top of the reactor. The four sections are similar in design: each is 3 3m high and 11.25m of resin catalyst can be loaded; 3 therefore, the total amount of catalyst loaded is 45m . Each section has a catalyst-loading inlet and a discharge outlet, a sprayer for water-in, and a derivate pipe. There is a gas distributor for feed gas under each catalyst bed, which consists of a gas flier trough and a bubble cap tray, the feed sprays through the slots of the bubble cap tray. The sprayer for water-in is located on the catalyst bed. The feed hydrocarbon was pumped from the bottom of the hydration reactor. There is a space of 1.1m height above each section to allow thermal expansion, and each bed has a space of 0.8m height for separating the fogs. The operating conditions of the hydration reactor were as follows: reaction temperature, 135 ℃—175℃; －1 －1 reaction pressure, 8.0MPa; LHSV, 1.0h — 1.2h ; mass flow rate of water and butane, 2.0 —2.5; and －1 online time, 8000h·a . 2.1.2 Dehydrogenation reactor Reaction pressure: 0.6MPa. Diameter: φ 1000mm. The catalyst loaded in the tubes and heat-conduction oil of 260℃—320℃ runs in shells. The volume of catalyst in each reactor was 700L. There were two reactors and the structure is as given below. Tubes are arranged in rows: φ 25mm×2.5mm, the length is 3000mm, total number of tubes is 740, which were arranged as a normal triangle, and the space between each tubes is 32mm. The operating conditions of the dehydrogenation reactor are: Reaction pressure in inlet, ≤0.2MPa; reaction temperature, 250 ℃—280℃; LHSV of SBA,
Figure 1 Process flow chart of n-butylene hydration and dehydrogenation 1—hydration reactor; 2 — phase-separator; 3—distillation column; 4—intermittent distillation column; 5 —ion column; 6—anion column; 7 —flash tower; 8—vaporization; 9—dehydrogenation reactor; 10 —condenser; 11 — phase-separator Chinese J. Ch. E. 14(5) 676 (2006)
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2.2.2 SBA dehydrogenation The reaction equation is: CH3CHOHCH2CH3 CH3COCH2CH3+H2 +Q －1 Q=－51kJ·mol . The reaction equilibrium constant K p is: lg K p = −
Figure 2 －1
4.0h ; the scheduled online time of catalyst, 1 year; and the period for catalyst regeneration, 6–8 weeks.
Through the above-mentioned reversible reactions, the carbonium ion can be reverted to any kind of butylenes or to SBA alternatively:
October, 2006 Propane
0.09
Table 1
T
+ 1.510lg T + 1.865
The by-reactions are: 2CH3CHOHCH2CH3 CH3CH2CH(CH3)O(CH3)CHCH2CH3＋H2O 2CH3COCH2CH3＋H2 CH3CH2C(CH3)CHCOCH2CH3＋H2O The process is an endothermic reaction, with the number of molecules increasing. From the thermodynamic point of view, low temperature and high pressure will benefit the reaction.
Diagram of a hydration reactor
2.2 Reaction routes 2.2.1 n-butylene hydration reaction The general reaction equation of butylene hydration is: n-C4H8+H2O CH3CH(OH)CH2CH3+Q This is an exothermic reaction: －1 [1] for n- butylene , Q=43kJ·mol －1 [2] for cis-butylene , Q=38.6kJ·mol －1 [3] for trans-butylene , Q=36.5kJ·mol . The main by-reactions are: C4H9OH+n-C4H8 CH3CH2(CH3)CHOCH(CH3)CH2CH3+H2O 2C4H9OH CH3CH2(CH3)CHOCH(CH3)CH2CH3+H2O (SBE) The reaction mechanism of ion exchange resin catalyst with strong acid is based on the conversion of buty+ lenes in the presence of H to the same carbonium ions:
2.790
2.3
Feed The composition of butylene feed is listed in Table 1. 2.4 Catalyst preparation 2.4.1 Specialty resin catalyst of high temperature [11] resistance for butylenes hydration (1) Polymerization reaction A total of 64% (by mass) styrene and 7.5% (by mass) divinylbenzene were mixed together, and then 27.5% (by mass) 56# paraffin wax and 1% (by mass) benezoperoxide were added to form the oil phase. Water phase was obtained using polythene alcohol 0.15% (by mass) and methylene blue 0.01% (by mass), which were then added to deionized water 99.84% (by mass). The volume ratio of water phase to oil phase was 4.5︰1. The water phase was heated to 60℃ with stirring, oil phase was added within 2h, and then the stirring was adjusted to control the size and equality of oil drops. Solidification of oil drops occurred at 95 — 100℃ in 10h. Then, 245—833μm polymer resin was obtained after the oil drops were washed with hot water, dried, and sieved. (2) Physics structure stabilization The polymer resin was swelled for 3h using dichloroethane, and unstable components were removed using series derivatives. The volume of the solvent was about 3 times that of the polymer resin and was maintained at 4.0MPa and 160℃ for 15h. The stabilization was completed after the polymer resin was purified by ethanol for 15h, washed, and dried. (3) Bromination The polymer resin was initially swelled using
The composition of butylene feed (%, by mass)
Propylene
n-Butane
cis-Butylene-2
trans-Butylene-2
n-Butylene-1
iso-Butylene
0.22
19.85
31.76
46.54
0.67
0.40
Development and Commercial Application of MEK Production Technology
dichloroethane, and then ferric chloride 1% was added with stirring, with the temperature maintained below 20℃;subsequently, bromine was slowly added and the temperature was reduced to 0 ℃, After stirring for 10h, the bromination was completed, after which the polymer resin was filtered, washed, and dried. (4) Sulfonation reaction The polymer resin was swelled using dichloroethane. Oleum (50%) was then added slowly with stirring, with the temperature maintained below 30℃. Stirring was then continued for 12h at 50℃. The br ominated and strongly acidic cation exchange resin was obtained after washing sequentially with NaCl solution, hydrochloric acid, deionized water until the resin water was neutral. (5) Active group stabilization The special high-temperature catalyst for butane hydration (DNW) was obtained by treating the sulfonic resin that was placed in an autoclave with deionized water that was about 1 time that of the polymer resin. The resin was heated to 150 —200℃ at 1MPa for 15d and washed using deionized water. Using the above-mentioned process, for every 3 batch in the commercial run, 5m of DNW speciality resin high-temperature catalyst could be obtained, and the total amount of DNW catalyst needed for butane 3 hydration was 45m . The chara cteristics of the DNW specialty catalyst are listed in Table 2. Compared with the traditional methods, the specialty catalysts that were prepared using the special method mentioned above had the following excellent characteristics: (1) high purity; (2) high stability; (3) after the purification, the pore volume and specific surface area were increased considerably. So the pore size would centralize and distribute evenly; the life of Table 2
catalyst. (1) Thermal stability In a glass tube, whose inner diameter was 10mm, 3ml of catalyst and 6ml of water were added; the glass tube was sealed and placed in a high-pressure kettle. At a temperature of 200℃, the samples were collected every 8h. Then the exchange capacity of the resin catalyst and the loss of sulfonic acid group were measured according to HG2-885-76. The result is shown in Fig.3.
Figure 3
Static state satuation between the special catalyst and reference ◆ B-24; ■ DNW catalyst
It can be seen from Fig.3 that the fraction of loss of sulfo radical was lower than that of the overseas reference resin catalyst over 64h, which was tested at 200℃. (2) Hydration activity The reaction conditions were as follows: tem perature, 150℃; pressure, 6.0MPa; water/butylene －1 molar ratio, 1.0; LHSV, 1.5h . The result for 120h is shown in Fig.4. From Fig.4 it was observed that for 120 h of continuous running, the average conversion of DNW specialty resin catalyst was 5.42%, about 5.1% higher than that of the reference commercial catalyst.
The characteristics of hydration catalysts
Item appearance
679
①
DNW
B-24
brown particle
bottle-green particle
strong acid
strong acid
type
+
H type
H+ type
water content, %
50.00
57.00
particle size, mm
0.40—1.20
0.40—1.20
0.90
0.95
1.30
1.09
10.00—20.00
0.31
ion status
wet specific volume, ml·g exchange capacity, mol·L
－1
－1 －1
specific surface area, m 2·g
① The catalyst was produced by Rohm & Hass in the USA.
catalysts was considerably extended, and the loss of sulfo radicals was decreased. 2.4.2 Comparison of specialty catalyst and overseas commercial catalyst To indicate the predominant capability of the specialty catalyst, the catalytic activity of the DNW specialty catalyst was compared with that of the B-24 Chinese J. Ch. E. 14(5) 676 (2006)
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Figure 4 Reference catalyst and specialty catalyst of high temperature resistance for hydration reactions ◆ B-24; ■ specialty catalyst for high temperature
2.4.3 Specialty FDH SBA dehydrogenation cata[12―14] lyst (1) Preparation of matrix catalyst Aluminum nitrate (220kg) and zinc nitrate (254kg) with copper nitrate (338kg) as solution were mixed in 3 3m of deionized water. Sodium carbonate (498kg) and 3 deionized water (3m ) were mixed as precipitator. 3 A little deionized water was added into a 10m reaction tank to submerge the stirrer and heated to 85℃, the water solution and precipitator were separately heated to 85℃ and then added to the tank in parallel-flow, slowly with strong stirring for about 1.5h; the temperature was kept at 85℃ and pH was adjusted to 7.0—8.0 by controlling relative flow-rate of water solution and precipitator and then sodium hydroxide solution was added to adjust the pH to 9.5. The precipitate was washed using deionized water after aging for 0.5h, it was then dried until the water content was reduced to 0.5%, uniformly mixed with 25kg graphite, and then it was made into φ 5mm×5mm pellets and calcined at 380℃ for 6h; 305kg of matrix catalyst was thus obtained and it contained 46.0% (by mass) copper oxide, 18.5% (by mass) alumina oxide, and 35.5% (by mass) zinc oxide. (2) Alkali metals loading A total of 150kg of the matrix catalyst was added into a 500L vitreous enamel tank, which had a wa−1 ter-cooling system, 300L of niter (1.5mol·L ) was Table 3
3 RESULTS AND DISCUSSION 3.1 Optimization of the n-butylene hydration process parameters 3.1.1 Influence of reaction temperature on conver sion －1 Under the conditions of 8.0MPa pressure, 0.34h LHSV, and water/butylene molar ratio of 10, the influence of reaction temperature on conversion was investigated in the commercial unit. The results are shown in Fig.5. From Fig.5 it can be seen that reaction temperature had a considerable influence on the conversion. The higher the temperature, the greater the speed of reaction until 150℃. Under the above-mentioned
Characteristics of FDH dehydrogenation catalyst
Item appearance particle size, mm component −1
pore volume, ml·g specific surface area, m 2·g−1 bulk density, g·ml
added and heated for 3h with liquid cycling, then dried, and calcinated at 360℃ for 6h. FDH catalyst for SBA dehydrogenation was thus obtained, which contained 45.4% copper oxide, 18.3% alumina, 35.1% zinc oxide, and 1.2% kalium oxide. Before being used, catalyst should be activated by nitrogen/hydrogen mixed gas or SBA under tem perature of 150–200℃. FDH catalyst prepared for SBA dehydrogenation has advantages, such as high strength, good selectivity, long running time, low cost, and simple preparation. The characteristics of the catalyst are listed in Table 3. 2.4.4 Comparison of the specialty FDH dehydrogenation catalyst and other catalysts To show the better capability of the FDH catalyst, author compared the results of specialty FDH catalyst on the 200ml secondary butanol test equipment in miniature with those of the D01 catalyst, which was produced by JGC in Japan, under the following conditions: temperature, 260℃; pressure, 0.2MPa; LHSV, －1 0.34h . The results are listed in Table 4. From Table 4 it can be found that of all the catalysts used worldwide, the FDH catalyst showed maximum reactivity.
−1
average pore diameter, nm radial crashing strength, MPa
①
FDH
D01
pellets Φ5×5
pellets Φ6×6
CuO-ZnO-Al 2O3
CuO-ZnO
0.15—0.20
0.12
58.00
36.2 (average)
1.48
1.75
12.00
13.60
≥14.00
10.00 (average)
① D01 was produced by Deraito in Japan. Table 4
Comparison of reactivity of different catalysts
Catalyst
Conversion of alcohol,%
Selectivity of MEK, %
Selectivity of C8 ketone, %
FDH
81.90
97.40
2.50
D01
76.80
96.80
2.70
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Development and Commercial Application of MEK Production Technology
reaction condition, the concentration of SBA in water solution is close to the equilibrium concentration; if the temperature is increased, the by-reaction occurs easily. So, normally, the reaction temperature cannot exceed 150℃.
Figure 5
Curve of temperature to conversion
3.1.2 Influence of reaction pressure on conversion Under the condition of butylene concentration of 88%, the influence of reaction pressure on conversion was observed. The results are shown in Table 5. It was found that the reaction pressure could considerably affect the hydration of butylenes. When temperature was 150℃, the saturated vapor pressure of water, cis-butylene-2, and trans-butylene-2 was 4.918MPa, 3.435MPa, and 3.712MPa, respectively. The total saturated vapor pressure was about 4.0MPa. When the pressure reached 5.0MPa, n-butylene existed under the condition of supercritical pressure. The effect of increase of pressure on the solubility of n-butylene seemed negligible. 3.1.3 Influence of feed butylene concentration on conversion Under the conditions of 8.0MPa pressure, 150℃ －1 temperature, 0.34h LHSV, and 10 water/butylene molar ratio, the influence of feed butylene concentration on conversion was investigated. The results are shown in Fig.6.
Figure 6
Curve of concentration versus conversion Table 5
681
From Fig.6, it was observed that the conversion of butylenes was linear with the feed butylenes concentration. The higher the butylenes concentration in feed, the larger the driving force necessary to drive n-butylene from the organic phase to the water phase, which resulted in high n-butylene concentration on catalyst surface and made the reactions easier. Apart from n-, cis-, and trans-butylenes, there were impurities, such as propane, n-butane, propylene, and iso-butylenes, in the raw material. The partial pressure of n-butylenes decreased when the impurities increased; therefore, the impetus of the reaction was reduced. Therefore, the conversion of the reaction increased with the increase of the concentration of n-butylenes. 3.1.4 Influence of LHSV on conversion When pressure was 8.0MPa, temperature was 150℃, and the concentration of butylenes was 88%, the influence of the water/butylene molar ratio on conversion was investigated. The results are shown in Fig.7.
Figure 7 Influence of water/butylenes on conversion ◆ LHSV 0.2; ■ LHSV 0.34; ▲ LHSV 0.5; LHSV 1.0
The influence of LHSV on conversion was investigated under the following conditions: pressure, 8.0MPa; temperature, 150℃; and water/butylene molar ratio, 1.5. The results are shown in Fig.8.
Figure 8 Influence of LHSV on conversion concentration of butylenc: ▲ 99%; ■ 77%
Influence of reaction pressure on conversion
Pressure, MPa
Temperature, ℃
Water/butylene mol ratio
Volume velocity of nC4, － h 1
Average conversion of butylenes, % (mol)
4.00
150
10
0.34
9.80
6.00
150
10
0.34
10.10
8.00
150
10
0.34
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Chinese J. Ch. E. (Vol. 14, No.5)
From Figs.7, 8 it can be observed that water/butane molar ratio and LHSV had considerable influence on conversion and that the conversion of a related curve became higher as the molar ratio of water/butane increased. So, with a fixed water/butanes molar ratio (or fixed total water amount), total conversion improvement depended on stepping seed. 3.2 Optimization of operating parameters for SBA dehydrogenation 3.2.1 Influence of temperature －1 Under normal pressure, LHSV of 4.0h for SBA, and temperature of 230 —290℃, the influence of tem perature on SBA conversion and MEK selectivity was tested with FDH catalyst. The results are shown in Fig.9.
Figure 9
3.2.2 Influence of pressure The overall reaction is a gas phase reaction increased with the number of molecules, so while the reaction pressure increased, the conversion of SBA decreased. The equilibrium conversion of SBA dehydrogenation could be expressed as given below: 1
⎛ K p ⎞ 2 X = ⎜ ⎟ ⎜ P + K p ⎟ ⎝ ⎠ −2790 lg K p = + 1.510lg T + 1.865
T where: X , conversion of SBA; P , reaction pressure, MPa; K p, equilibrium constant of SBA dehydrogenation, MPa; T , reaction temperature, K. The relationship of reaction pressure and equilibrium conversion is shown in Fig.11.
Influence of reaction temperature on conversion
■ selectivity of MEK; ▲ conversion of SBA; ◆ selectivity of C8 ketone
Figure 11
From Fig.9 it can be observed that there was an obvious increase in the conversion of SBA as the reaction temperature increased. The conversion of SBA was above 80% while the temperature was over 250℃, and the selectivity of MEK slightly increased, all more than 95%, and the selectivity of C8 ketone declined. The by-reaction of SBA dehydration increased when the reaction temperature continued to rise. From Fig.10 it can be observed that SBA could dehydrate and crack easily when the reaction tem perature rose, and carbon deposited on catalyst became more concentrated. So, lower reaction temperature was good for the long-period catalyst operation and for maintaining adequate SBA conversion.
Figure 10
Variety of butylenes and water to reaction temperature Table 6
Temperature, ℃
－1
LHSV, h
Relation of equilibrium conversion and pressure ◆ 230℃; ■ 260℃
Under the condition of temperature of 260 ℃, the results of different reaction pressure are listed in Table 6. From Table 6 it can be observed that the conversion of SBA and the selectivity of MEK decreased with increase in pressure because of the increasing rate of the MEK condensation reaction. But for the pressure drop and industrial equipment controlling, actual pressure must be about 0.2MPa. Under this pressure, the conversion of SBA could reach more than 80% under conditions of temperature of 260℃ －1 and LHSV of 4.0h . 3.2.3 Influence of LHSV Under normal pressure and temperature of 260 ℃, the influence of LHSV on the conversion of FDH catalysts was investigated. The results are shown in Fig.12. Figure 12 indicates that the conversion of SBA decreased with the increase of LHSV, whereas the MEK selectivity increased. Because the MEK condensation reaction slowed down with the decrease in residence time, the quantity of byproduct C 8 ketone was reduced. If the LHSV was too high, the conversion of SBA was reduced and the circulation of SBA
Influence of reaction pressure on conversion
Pressure, MPa
Conversion of SBA, %
Selectivity of MEK, %
Selectivity of C8 ketone, %
260
4.00
0.10
85.33
97.65
2.41
260
4.00
0.20
81.81
96.25
3.24
260
4.00
0.50
65.34
93.23
6.22
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Development and Commercial Application of MEK Production Technology Table 7
683
The commercial operating conditions of MEK unit
Item
FRIPP
Germany technique
97.0
97.0
135—175
160
6.0
6.0
LHSV, h
1.0—1.5
1.5
water/butylenes ratio
1.0—1.5
1.0
10.3
14.0
8.0 —11.0
6.0
98
98
90.0
80.0
23.0
22.0
9000
8000
230—260
260
①
hydration reaction n-butylene concentration, % (by mass) temperature, ℃ pressure, MPa －1
recycle ratio single pass conversion of butylenes, % SBA selectivity, % n-butylene conversion, % catalyst volume, m
3
catalyst life, h dehydrogenation reaction temperature, ℃ pressure, MPa
0.1
0.2
－1
LHSV, h
4.0
4.0
SBA conversion, %
96.7
>80.0
MEK selectivity, %
96.6
>95.0
>3500
1008 —1344
catalyst life, h
① The data was gained in Chinese industry by using technology from Germany.
prolonged. At the same time, the low recycle ratio of n-butylene resulted in the decreasing of recycling amount of n-butylene. And the operation cycle of the dehydrogenation catalyst was prolonged. 4 Figure 12 Influence of LHSV on conversion ◆ selectivity of MEK; ■ conversion of SBA
increased, so the energy consumption increased. In general, the conversion of SBA was greater than 80%. Under the temperature of 260℃, the appropriate －1 LHSV of SBA was around 4.0 h . 3.3
Commercial MEK technology The MEK production technology via n-butylene hydration/SBA dehydrogenation was commercialized －1 in a 20kt·a unit. The specialty resin catalyst of high temperature-resistance for butylenes hydration and the specialty FDH SBA dehydrogenation catalyst have been developed and used in this unit. The unit was started-up only by one trial, the conversion and selectivity all met the design targets, and MEK product complied with the ASTM standard. The commercial results and reference technique data are shown in Ta ble 7. Compared the data listed above, it can be found that, using the technology developed FRIPP, though the volume of catalyst is slightly increased, the initial temperature of reaction was lower than before, the conversion was enhanced and the life of catalyst was
CONCLUSIONS (1) Based on the laboratory and pilot plant studies in FRIPP, the whole set of production technology for n-butylene hydration and MEK production by dehydrogenation was successfully commercialized. The two specialty catalysts were both commercialized and successfully used in the commercial MEK unit. －1 (2) On the basis of FRIPP technology, a 20kt·a MEK production unit was built and it operated well after first starting-up, and the MEK product met the ASTM standard. (3) Compared with those of the same kind of overseas catalysts, the both activity and selectivity of the two specialty catalysts were excellent. (4) The MEK production technology is the intellectual property of FRIPP and it reaches the world advanced level comparable with the other existing licensors’ technology. REFERENCES 1
2
3
Li, Y.L., “Production technology and market analysis of methyl ethyl ketone”, Fine and Specialty Chemicals, 12(18), 22—25(2004). (in Chinese) Zhang, Y.X., “Production technology and application status of methyl ethyl ketone”, Journal of Henan Chemical Industry, 11(1), 51—55(2003). (in Chinese) Qi, J., Gao, N., “Market analysis of methyl ethyl ketone”, Petrochemical Industry Technology, 10(3), 61 — 64(2003). (in Chinese) Chinese J. Ch. E. 14(5) 676 (2006)
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Chinese J. Ch. E. (Vol. 14, No.5)
Perez-Lopez, O.W., Farias, A.C., Marcilio, N.R., Bueno, J.M.C., “The catalytic behavior of zinc oxide prepared from various precursors and by different methods”, Mater . Res. Bull ., 40(12), 2089—2099(2005). Kacimi, M., Ziyad, M., Hatert, F., “Structural features of AgCaCdMg 2(PO4)3 and AgCd2Mg2(PO4)3, two new compounds with the alluaudite-type structure, and their catalytic activity in butan-2-ol conversion”, Mater . Res. Bull ., 40(4), 682—693(2005). Cheikhi, N., Kacimi, M., Rouimi, M., Ziyad, M., Liotta, L.F., Pantaleo, G., Deganello, G., “Direct synthesis of methyl isobutyl ketone in gas-phase reaction over palladium-loaded hydroxyapatite”, Journal of Catalysis, 232(2), 257—267(2005). (in Chinese) Driver, P., Glowa, G., Wren, J.C., “Steady-state γ-radiolysis of aqueous methyl ethyl ketone (2-butanone) under postulated nuclear reactor accident conditions”, Radiation Physics and Chemistry, 57(1), 37—51(2000). Smetana, J.F., Falconer, J.L., Noble, R.D., “Separation of
October, 2006
9
10 11
12 13
14
methyl ethyl ketone from water by pervaporation using a silicalite membrane”, Journal of Membrane Science, 114(1), 127—130(1996). (in Chinese) Wu, Z.G., Zhu, S.K., Zhai, Q.T., “A process of low car bon alcohol by hydration directly from low carbon alkene” C.N. Pat., 1210847(1999). Wu, Z.G., Zhu, S.K., Wan, J., “A process of seriate production low carbon alcohol”, C.N Pat., 1289748(2001). Xu, B.S., Zhang, G.L., Li, H.Y., “A process of cation exchange resin catalysts with high temperature resistance”, C.N Pat., 1076385A(1993). Ma, Y.S., Su, J., “A process of a Cu contained catalyst”, C.N Pat., 1289638(2001). Ma, Y.S., Su, J., Wang, C.M., “A process of ketone from secondary alcohol by dehydrogenation”, C.N Pat., 1289753(2001). Ma, Y.S., Su, J., Wang, C.M., “A process of aldehydes and ketones from alcohol by dehydrogenation”, C.N Pat., 1289752(2001).
