CN101293804B - Fluidizer and method for preparing ethylene with ethanol dehydration - Google Patents

Abstract

A fluidized device for ethanol dehydration to ethylene, including a fluidized bed reactor, a regenerator, a catalyst riser, a stripper, and a catalyst mixed degassing tank, wherein the stripper and the regenerator are connected by a raw catalyst delivery pipeline The fluidized bed reactor is directly connected to the catalyst riser, the catalyst mixing degassing tank is connected to the regenerator through the regenerated catalyst delivery pipeline, the catalyst mixing degassing tank and the catalyst riser are connected through the mixing catalyst delivery pipeline, and the catalyst The mixed degassing tank is connected with the stripper through the catalyst internal circulation pipeline. The invention effectively removes the flue gas carried by the regenerated catalyst by adding a catalyst mixing and degassing tank, so that the purity of ethylene in the product is greatly improved. The regenerator is set up separately, or it can be shared with the catalytic cracking unit in the petroleum refining field.

Description

Fluidization device and method for ethanol dehydration to ethylene

technical field

The present invention pertains to an apparatus and method for the preparation of hydrocarbons from a non-hydrocarbon compound, and more particularly to an apparatus and method for the dehydration of an oxygenate to produce ethylene.

Background technique

Ethylene is the most important basic raw material in the petrochemical industry. At present, about 75% of petrochemical products come from ethylene. At present, the world's ethylene production capacity has reached 112.9055 million tons per year, and it is expected that the world's ethylene production capacity will reach 144.455 million tons per year in 2012. In 2010, my country's ethylene equivalent demand is expected to be 25.7 million tons per year, the production capacity is 13.89 million tons per year, and the self-sufficiency rate is only 54%. Therefore, whether it is domestic or foreign, there is still a lot of room for the development of the ethylene market.

There are many ways to produce ethylene, mainly including hydrocarbon cracking method, synthesis gas synthesis method, ethanol dehydration method, propylene disproportionation method and so on. At present, the industrial production of ethylene is mainly prepared by steam cracking of hydrocarbons. Since the steam cracking of hydrocarbons in the world mainly uses naphtha and ethane as raw materials, the selection of raw materials is a major technical and economic problem, and the cost of raw materials accounts for 60% to 80% of the cost of ethylene. The main factors affecting the change of ethylene raw materials are the supply and price of oil and natural gas. From a global perspective, oil resources are decreasing day by day, coupled with the uneven distribution of oil resources, it is even more necessary to develop substitutes for oil resources to reduce the dependence on oil.

The reaction chemistry of ethanol dehydration to ethylene (hereinafter referred to as ETE) has been reported as early as the 18th century, and it was the main method of ethylene production before the development of petrochemical industry. Later, with the development of the oil industry, ETE was economically uncompetitive, so that the ETE plant was basically shut down. However, ETE technology also has its own advantages: compared with other methods, its product purity is high, the equipment is simple, the investment is less, and the effect is quicker. With the increasing depletion of oil resources, the increase in mining costs, rising oil prices, human beings are increasingly concerned about the environment, limiting greenhouse gas emissions, the society pays attention to the interests of farmers and the need to achieve sustainable development, especially with the development of biomass fermentation ethanol technology Progress has reduced the cost of ethanol raw materials. More and more attention has been paid to the technical routes of ethanol production from renewable biomass and ethanol dehydration to ethylene. The use of ETE to produce ethylene has great economic value and strategic significance.

The following chemical reactions occur in the dehydration of ethanol to ethylene:

CH ₃ CH ₂ OH (ethanol)→CH ₂ =CH ₂ (ethylene)+H ₂ O (water)

This reaction is a strong endothermic reaction, △H° ₂₉₈ =44.912kJ/mol, the higher the reaction temperature, the more favorable the formation of ethylene, but too high temperature will promote the formation of by-products such as acetaldehyde. The ethanol dehydration reaction is an acid-catalyzed dehydration reaction. The use of liquid acid catalysts and solid acid catalysts can reduce the activation energy of the reaction and accelerate the reaction. Concentrated sulfuric acid is used as catalyst, which is conducive to the dehydration of ethanol to ethylene at 170°C, and is conducive to the formation of ether at 140°C; using γ-Al ₂ O ₃ as catalyst, due to its weak acidity, the reaction temperature of ethanol dehydration to ethylene It needs to be at 350-400°C, and if the temperature is lower (at 260°C), ether will be generated. When the reaction temperature is higher than 404°C, ethanol will be directly dehydrogenated to form acetaldehyde. Therefore, the ETE reaction needs to control the reaction temperature range to reduce the occurrence of side reactions.

The ETE industrial technology route is divided into two types according to the type of reactor used, the fixed bed process technology route and the fluidized bed process technology route, both of which adopt the ethanol gas phase dehydration process route. Under the same processing capacity, the investment cost and operating cost of the fluidized bed process technology route are lower than the fixed bed process technology route.

US4134926 discloses the use of a fluidized bed reactor to carry out the ETE reaction, the catalyst can be alumina, activated clay, molecular sieves and the like. The temperature of the reactor is maintained above 700°F (about 371°C). After the reaction, a part of the catalyst goes to the regenerator to burn and regenerate, and the regenerated catalyst is recycled back to the reactor for reaction.

The main problem of using a fluidized bed reactor for ETE is that the regenerated catalyst entrains flue gas, which contains a large amount of impurity gases such as nitrogen, oxygen, carbon dioxide, carbon monoxide, etc., and the regenerated catalyst entrained with flue gas returns to the fluidized bed for reaction The device will increase the side reaction and greatly reduce the purity of ethylene in the product, requiring expensive cryogenic separation to improve its purity.

Contents of the invention

The purpose of the invention is to design a fluidized device for producing ethylene by ethanol dehydration on the basis of the prior art, so as to improve the purity of ethylene in the product.

Another object of the present invention is to provide a fluidized method for ethanol dehydration to ethylene on the basis of the prior art, so as to improve the purity of ethylene in the product.

The fluidized device for ethanol dehydration to ethylene designed in the present invention includes a fluidized bed reactor, a regenerator, a catalyst riser, a stripper, and a catalyst mixing and degassing tank, wherein the stripper and the regenerator are transported through a spent catalyst The fluidized bed reactor is directly connected to the catalyst riser, the catalyst mixing and degassing tank is connected to the regenerator through a regenerated catalyst delivery pipeline, and the catalyst mixing and degassing tank is connected to the catalyst riser through a mixed catalyst delivery pipeline. The catalyst mixing and degassing tank is connected with the stripper through a catalyst internal circulation pipeline.

The catalyst riser can be in the form of an inner riser arranged coaxially or non-coaxially with the fluidized bed reactor, and can also be in the form of an outer riser arranged non-coaxially with the fluidized bed reactor. The outlet of the inner riser extends into any part of the fluidized bed reactor, preferably extends into the bottom or lower part of the fluidized bed reactor. The outlet of the outer riser extends into any part of the fluidized bed reactor or the lower part of the settler above the fluidized bed reactor, preferably extends into the bottom of the fluidized bed reactor or the lower part of the settler.

The stripper is arranged coaxially or non-coaxially with the fluidized bed reactor. When the stripper is coaxially arranged with the fluidized bed reactor, the stripper is directly communicated with the fluidized bed reactor. When the stripper is arranged non-coaxially with the fluidized-bed reactor, the stripper and the fluidized-bed reactor are successively connected to each other through the flooded tube of the raw catalyst, the hopper of the raw catalyst and the pipeline, and the stripper It is connected with the settler through a pipeline.

A raw material inlet is arranged at least one position in the catalyst riser and the fluidized bed reactor. A cyclone separator and an optional gas collection chamber are provided at the outlet of the fluidized bed reactor, wherein the cyclone separator is necessary and the gas collection chamber is optional. When there are many sets of cyclone separators, it is necessary to set up a gas collection chamber.

A gas-solid distributor is provided at the outlet of the catalyst riser. A stripping baffle is provided in the spent catalyst stripper.

The bottom of the catalyst mixed degassing tank is provided with a steam inlet, and the top is provided with a flue gas outlet, and the flue gas outlet may or may not be connected with the regenerator.

Control valves are provided on the waiting catalyst delivery pipeline, the regenerated catalyst delivery pipeline, the catalyst internal circulation pipeline and the mixed catalyst delivery pipeline.

The regenerator can be set independently or shared with the catalytic cracking unit. In the case of sharing the regenerator with the catalytic cracking unit, the regenerator is also connected to the stripper and the reactor of the catalytic cracking unit through the delivery pipeline of the spent catalyst and the delivery pipeline of the regenerated catalyst respectively.

The fluidized method for ethanol dehydration to ethylene provided by the present invention includes: the regenerated catalyst comes out of the regenerator through the regenerated catalyst delivery pipeline and enters the catalyst mixing degassing tank, and removes the flue gas entrained by the regenerated catalyst through water vapor or/and carbon dioxide and simultaneously with part After the raw catalyst is mixed, it enters the catalyst riser through the mixed catalyst delivery pipeline, and the water vapor or/and gasified ethanol raw material is used as the catalyst pre-lift gas, and the catalyst is lifted into the fluidized bed reactor through the catalyst riser, and the catalyst and ethanol raw material Contact, at a reaction temperature of 250-500°C, preferably 300-450°C, a pressure of 0-1.0MPa, preferably 0-0.5MPa (gauge pressure), and a weight hourly space velocity of 0.5-10h-1, preferably 0.5-5h ^-1 Gas-phase catalytic dehydration reaction occurs, and the gas product enters the gas collection chamber after the catalyst is recovered by the cyclone separator, and the product stream is sent to the downstream separation section, and the reacted raw catalyst enters the raw catalyst stripper for stripping and is divided into two parts , a part of which enters the regenerator for regeneration, and the other part enters the catalyst mixing and degassing tank to mix with the regenerated catalyst.

The ethanol raw material can be absolute ethanol, or crude ethanol containing water and a small amount of impurities.

The catalyst is selected from one or more of alumina, active clay and catalysts containing Y series zeolite. In the case of sharing the regenerator with the catalytic cracking unit, the catalyst is preferably a catalyst containing Y series zeolites.

The preheating temperature of the ethanol raw material is 25-500°C, preferably 200-400°C; the temperature of the regenerated catalyst from the regenerator is 500-720°C, and the temperature of the regenerated catalyst after degassing and mixing in the catalyst mixing and degassing tank is 300-500°C.

The weight ratio of the spent catalyst entering the catalyst mixing and degassing tank to the spent catalyst entering the regenerator is 1-30:1.

The device and process method of the present invention can be operated independently, and can also share the catalyst and regenerator with the refinery unit FCC.

The device of the present invention adds a catalyst mixing degassing tank and adds a regenerated catalyst degassing step in the method to effectively remove the flue gas entrained by the regenerated catalyst, so that the purity of ethylene in the product is greatly improved. In addition, the present invention introduces part of the spent catalyst in the stripper into the catalyst mixing and degassing tank through another spent catalyst delivery pipeline, mixes it with the regenerated catalyst, effectively adjusts the reaction temperature, and ensures the heat balance and optimal reaction temperature of the whole process. interval.

Description of drawings

Fig. 1 is a schematic flow chart of the fluidized device and method of ethanol dehydration to ethylene provided by the present invention when the riser is built in.

Fig. 2 is a schematic flow diagram of the riser extending into the bottom of the fluidized bed reactor when the riser is placed externally.

Fig. 3 is a schematic flow diagram of a riser built in and a stripper outside.

Detailed ways

The device and method provided by the present invention will be further described below in conjunction with the accompanying drawings, but the present invention is not limited thereby.

The device provided by the present invention comprises a fluidized bed reactor 2, a regenerator 19, a catalyst riser 7, a stripper 6, a catalyst mixing degassing tank 10, wherein between the stripper 6 and the regenerator 19, a spent catalyst The transfer pipeline 17 is connected, the fluidized bed reactor 2 is directly connected with the catalyst riser 7, the catalyst mixing and degassing tank 10 is connected with the regenerator 19 through the regenerated catalyst delivery pipeline 15, and the catalyst mixing and degassing tank 10 is connected with the catalyst riser 7 They are connected through a mixed catalyst delivery line 12 , and the catalyst mixed degassing tank 10 is connected with the stripper 6 through a catalyst internal circulation line 8 .

A cyclone separator 1 is provided at the outlet of the fluidized bed reactor 2 .

A gas-solid distributor 4 is provided at the outlet of the catalyst riser 7 . A stripping baffle 5 is provided in the spent catalyst stripper 6 .

Control valves 18 , 16 , 9 , and 13 are provided on the standby catalyst delivery pipeline 17 , the regenerated catalyst delivery pipeline 15 , the catalyst internal circulation pipeline 8 , and the mixed catalyst delivery pipeline 12 .

Fig. 1 is a schematic flow chart of the fluidized device and method of ethanol dehydration to ethylene provided by the present invention when the riser is built in.

The flow process of the fluidized method for ethanol dehydration to ethylene is as follows:

The high-temperature regenerated catalyst (with a temperature of 500-720° C.) from the regenerator 19 enters the catalyst mixing and degassing tank 10 through the regenerant delivery pipeline 15 and the control valve 16 . After the reaction, the stripped low-temperature standby catalyst enters the catalyst mixing and degassing tank 10 through the catalyst internal circulation pipeline 8 and the control valve 9 and mixes with the high-temperature regeneration catalyst in a certain proportion. The stripping medium water vapor or carbon dioxide enters the catalyst mixing degassing tank 10 through the pipeline 102 through the gas distributor 11 to strip the mixed catalyst to remove impurities such as flue gas carried by the catalyst and mix the hot and cold catalysts evenly in the mixing tank. The temperature reaches a temperature range suitable for the ETE reaction to proceed. The extracted flue gas and steam mixture can be discharged into the regenerator or vented through the pipeline 103. The homogeneously mixed catalyst enters the catalyst riser 7 through the mixed catalyst delivery pipeline 12 and the control valve 13 . The pre-lifting medium can be reaction raw material or water vapor, which enters the catalyst riser 7 through the pipeline 100 and the gas distributor 14 provided at the bottom of the catalyst riser 7 in sequence, and sends the catalyst to the fluidized bed reactor 2 to form a bed 3 .

The reaction raw material (preheating temperature is 25-500°C) can enter from the bottom of the riser as a pre-lift medium, or enter from different positions of the riser and the fluidized bed reactor, and contact with the catalyst to generate ethylene in the gas phase dehydration reaction. The way can be adjusted flexibly.

The ethanol dehydration reaction is an endothermic reaction. In order to ensure that the reactor is maintained at a suitable reaction temperature, the heat required for the reaction can be provided by the catalyst. Therefore, it is required that the catalyst mixing temperature in the catalyst mixing and degassing tank 10 reaches 300-500°C. It is found through calculation that in order to achieve the proper temperature of the pre-mixing chamber, the ratio of the low-temperature internal circulation catalyst to the high-temperature regenerant is about 1:1 to 30:1. A distribution facility 4 is provided at the outlet of the riser so that the catalyst is evenly distributed in the bed 3 . The reaction temperature is 250-500° C., the reaction pressure is 0-1.0 MPa (gauge pressure), the reaction weight hourly space velocity is 0.5-10 h ^-1 , and the reaction time is 0.1-20.0 seconds. After the reaction, the gas product enters the gas collection chamber 20 after recovering the catalyst carried by the cyclone separator 1, and the product stream 101 is sent to the downstream separation section. The reacted catalyst enters the stripping section 6 provided with the stripping baffle 5, and the carried reaction materials are stripped by steam. A part of the stripped catalyst enters the regenerator 19 through the standby delivery pipeline 17 and the control valve 18 for regeneration to complete a cycle; the other part is circulated back to the catalyst mixing and degassing tank 10 through the catalyst internal circulation pipeline 8 and the control valve 9 for The temperature of the catalyst entering the reactor is adjusted.

Fig. 2 is a schematic flow diagram of the riser extending into the bottom of the fluidized bed reactor when the riser is placed externally.

The main difference between Fig. 2 and Fig. 1 is that the riser is external and extends into the bottom of the fluidized bed reactor.

Fig. 3 is a schematic flow diagram of a riser built in and a stripper outside.

The main difference between Figure 3 and Figure 1 is that the stripper is external.

The following examples will further illustrate the method, but the method is not limited thereby.

Example

The relevant tests in the examples were carried out on a medium-sized device integrating ethanol dehydration to ethylene (ETE) and catalytic cracking (FCC) controlled in real time by a computer. The processing capacity of this device is 0.4t/d, and the raw material is 5% water content ethanol, the feed rate of ethanol is 1.2h ^-1 weight hourly space velocity, the fluidized bed reaction temperature is 380°C, and the reaction pressure is 0.2MPa. The catalyst is FCC catalyst GOR-2 catalyst (800° C., 100% steam aging for 17 hours) developed by Sinopec Petrochemical Research Institute.

The product distribution is shown in Table 1. From Table 1, it can be seen that the conversion rate of ethanol is 99.5%, and the purity of ethylene is as high as 99.0v%.

comparative example

Compared with the example, the regenerated catalyst mixed degassing tank is not installed in the comparative example, and the regenerated catalyst is cooled and then returned to the fluidized bed reactor from the regenerator, and the reaction conditions are the same as those of the example.

The product distribution is shown in Table 1. From Table 1, it can be seen that the conversion rate of ethanol is 99.5%, and the purity of ethylene is only 92.92v%.

Table 1

Example comparative example Ethanol conversion rate, % 99.5 99.5 Product composition, v% carbon dioxide 0.04 0.14 hydrogen 0.06 0.15 methane 0.01 0.21 ethane 0.05 0.25 Vinyl 99.00 92.92 propane 0.10 0.35 Propylene 0.14 0.41 Isobutane 0.12 0.38 n-butane 0.09 0.32 Butene-1 0.04 0.36 Isobutylene 0.04 0.33 trans-butene-2 0.10 0.37 Butene-2 0.08 0.28 Pentane 0.06 0.46 Pentene 0.07 0.50 Nitrogen 0.00 2.46 oxygen 0.00 0.07 carbon monoxide 0.00 0.04 total 100.00 100.00

Claims (17)

1. the fluidizer of a producing ethylene from dehydration of ethanol; Comprise fluidized-bed reactor, revivifier, stripper; Wherein link to each other through the reclaimable catalyst line of pipes between stripper and the revivifier; It is characterized in that this device also comprises catalyzer riser tube and catalyst mix degassing vessel, fluidized-bed reactor directly links to each other with the catalyzer riser tube, links to each other through the regenerated catalyst line between catalyst mix degassing vessel and the revivifier; Link to each other through the mixed catalyst line of pipes between catalyst mix degassing vessel and the catalyzer riser tube, catalyst mix degassing vessel and stripper with between link to each other through catalyzer internal recycle pipeline.

2. according to the device of claim 1, it is characterized in that described catalyzer riser tube is the interior riser tube form of or non-coaxial arrangement coaxial with fluidized-bed reactor, or with the outer riser tube form of the non-coaxial arrangement of fluidized-bed reactor.

3. according to the device of claim 2, it is characterized in that described interior riser tube exports bottom or the bottom of stretching into fluidized-bed reactor.

4. according to the device of claim 2, it is characterized in that described outer riser tube exports bottom or the bottom of stretching into fluidized-bed reactor.

5. according to the device of claim 1, it is characterized in that the coaxial or non-coaxial arrangement of described stripper and fluidized-bed reactor.

6. according to the device of claim 5, when it is characterized in that described stripper and fluidized-bed reactor coaxial arrangement, stripper directly is communicated with fluidized-bed reactor.

7. according to the device of claim 5; When it is characterized in that the non-coaxial arrangement of described stripper and fluidized-bed reactor; Between stripper and the fluidized-bed reactor successively through reclaimable catalyst flood the stream pipe, the reclaimable catalyst hopper links to each other with pipeline, link to each other through pipeline between stripper and the settling vessel.

8. according to the device of claim 1, it is characterized in that the ethanol raw material inlet is established at least one position in catalyzer riser tube, fluidized-bed reactor.

9. according to the device of claim 1, it is characterized in that establishing cyclonic separator and optional collection chamber in the outlet of fluidized-bed reactor.

10. according to the device of claim 1, it is characterized in that being provided with the gas-solid sparger, in the reclaimable catalyst stripper, be provided with stripping baffles in the outlet of catalyzer riser tube.

11., it is characterized in that on reclaimable catalyst line of pipes, regenerated catalyst line, catalyzer internal recycle pipeline, mixed catalyst line of pipes, being equipped with valve according to the device of claim 1.

12. according to the device of claim 1, it is characterized in that said revivifier is provided with separately, or with the shared catalytic cracking regenerator of the CCU in refining of petroleum field.

13. the fluidizing method of a producing ethylene from dehydration of ethanol is characterized in that this method comprises:

Regenerated catalyst comes out to get into the catalyst mix degassing vessel through the regenerated catalyst line from revivifier; Via water vapor or/and the flue gas that the CO2 removal regenerated catalyst is carried secretly simultaneously with after the part reclaimable catalyst mixes; Get into the catalyzer riser tube through the mixed catalyst line of pipes, water vapor is promoted to catalyzer in the fluidized-bed reactor through the catalyzer riser tube or/and the ethanol raw material of gasification promotes gas in advance as catalyzer; Catalyzer contacts with ethanol raw material; In temperature of reaction is 250 ~ 500 ℃, and pressure is 0 ~ 1.0MPa, and weight hourly space velocity is 0.5 ~ 10h ^-1Condition issue angry phase catalytic and dehydration reaction; Gas products gets into collection chamber after reclaiming the catalyzer that carries through cyclonic separator; Product stream fed downstream centrifugal station; Reacted reclaimable catalyst is divided into two portions after getting into reclaimable catalyst stripper stripping, and wherein a part gets into revivifier regeneration, and another part gets into the catalyst mix degassing vessel to be mixed with regenerated catalyst.

14. according to the method for claim 13, it is characterized in that described temperature of reaction is 300 ~ 450 ℃, pressure is 0 ~ 0.5MPa, weight hourly space velocity is 0.5 ~ 5h ^-1

15., it is characterized in that described ethanol raw material is an absolute ethyl alcohol, or the coarse ethanol of moisture and small amount of impurities according to the method for claim 13.

16., it is characterized in that said catalyzer is selected from aluminum oxide, activated clay and contains in the catalyzer of Y series zeolite one or more according to the method for claim 13.

17. according to the method for claim 13, the reclaimable catalyst that it is characterized in that getting into the catalyst mix degassing vessel is 1 ~ 30:1 with the ratio of the reclaimable catalyst weight that gets into revivifier.

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