CN201848255U - Catalyst reduction device for one-step catalytic synthesis of dimethyl ether gas - Google Patents

Abstract

The utility model discloses a one-step catalytic synthesis gas dimethyl ether catalyst reduction device, which mainly includes a fixed-bed reactor, a heat-conducting oil furnace, a compressor, an online hydrogen analyzer and a corresponding test system. A plurality of reaction tubes are distributed in parallel in the fixed bed reactor, the catalyst in the reaction tubes exchanges heat with the heat transfer oil outside the reaction tubes, and the reducing gas undergoes reduction reaction in the reaction tubes. Hydrogen and nitrogen are mixed into a certain proportion of reducing gas in the pipeline, and enter the synthesis tower for catalyst reduction reaction. The hydrogen content in the mixed gas is analyzed online by a hydrogen online analyzer. The temperature control of the fixed bed reactor is heated by a heat transfer oil furnace. The pipeline reaches the shell side of the reactor for heating, the heated heat transfer oil circulates into the heat conduction oil furnace for reheating, the reduction tail gas enters the compressor for pressurization, and circulates into the fixed bed reactor through the check valve. The utility model is optimized and integrated on the basis of the traditional catalyst reduction chemical unit, which greatly reduces the waste of nitrogen and hydrogen in the catalyst reduction process. The system can be used for various chemical reactions that need to be reduced before the reaction, and can be used on a large scale in one step. In the system of catalyzed synthesis of dimethyl ether by method, the commercial operation of dimethyl ether by method catalysis is promoted.

Description

One-step catalytic synthesis gas dimethyl ether catalyst reduction device

technical field

The utility model relates to the technical field of catalyst reduction reaction, in particular to a reduction device for synthesizing dimethyl ether catalyst in one step, and belongs to the field of coal/biomass chemical industry.

Background technique

Due to the increasing shortage of petroleum resources, environmental pollution and greenhouse problems are becoming more and more serious, obtaining high-grade liquid fuels and chemicals from biomass agricultural and forestry waste resources (such as straw, etc.) is gradually becoming a development trend, which has attracted great attention at home and abroad. Catalytic synthesis of high-grade liquid fuels (such as dimethyl ether, methanol, LPG, etc.) by biomass gasification is through the directional gasification of biomass, and the synthesis of liquid fuels and chemicals by catalysts. Therefore, improving the activity of catalysts has become a The technical core of the entire catalytic synthesis system. The market prospects of biomass-based liquid fuels and chemicals ultimately depend on cost competitiveness, so cost reduction has become a key link in their economics. At the same time, DME can be directly used as fuel as a substitute for liquefied petroleum gas and diesel.

At present, most of the one-step dimethyl ether synthesis and production remain in the laboratory and pilot stage, and its scale is relatively small, and the production cost is high. The large-scale production of DME adopts the direct conversion process of synthesis gas. Small scale and pilot scales do not have high requirements for the amount of reducing gas, and the cost does not appear. In the process of large-scale industrialization, cost saving will become an important economic indicator for the synthesis of dimethyl ether. Therefore, the saving of reducing gas in catalyst reduction will also be an important part of the synthesis cost of dimethyl ether.

The one-step catalytic synthesis of dimethyl ether catalyst reduction mainly contains the following two reactions:

CuO+ _H2 = _Cu2O + _H2O ; _Cu2O + _H2 =Cu+ _H2O ;

It can be seen that the catalyst reduction reaction of syngas one-step catalytic synthesis of dimethyl ether only needs _H2 as the reaction gas. However, in the reduction process, if pure _H2 is used for catalyst reduction, the reduced Cu grains will become larger, and the activity and life will be greatly reduced. Therefore, it is necessary to use _N2 as an inert gas to dilute _H2 to reduce the reduction. speed to achieve the best reduction effect of the catalyst.

Utility model content

The purpose of this utility model is to optimize the system design for the waste of reducing gas _H2 and _N2 in the reduction process of the catalyst for synthesizing dimethyl ether. Without affecting the reduction effect of the catalyst for synthesizing dimethyl ether, the hydrogen content is between 0 and 25%, 0.3 ~ 0.5MPa, normal temperature to 270 ℃ temperature program for catalyst reduction reaction, provide a simple, easy to operate, reliable technology, can save 80% of _N2 and 50% of _H2 , and optimize the integration of the system A one-step catalytic synthesis gas dimethyl ether catalyst reduction device.

In order to achieve the above object, the utility model adopts the following technical scheme: a catalyst reduction device for one-step catalytic synthesis of dimethyl ether, including a fixed bed reactor, a plurality of reaction tubes are distributed in parallel in the fixed bed reactor, and the fixed bed reactor There is a temperature measuring point in a tube at the bottom of the bed reactor, a reducing gas inlet on the top, a reduced tail gas outlet on the bottom, two symmetrical heat transfer oil inlets on the lower side, and a heat transfer oil outlet on the upper side; The heat transfer oil furnace is used for storage and heating of heat transfer oil. The heat transfer oil furnace is connected to the fixed bed reactor through the heat transfer oil inlet, and the heat transfer oil outlet is connected to the heat transfer oil furnace through pipelines. The heat transfer oil inlet and outlet of the heat transfer oil furnace are equipped with temperature At the same time, according to the program setting, the temperature of the heat transfer oil entering the shell side of the fixed bed reactor is controlled. After heat exchange in the fixed bed reactor, the heat transfer oil flows out from the outlet of the heat transfer oil and re-enters the heat transfer oil furnace for heating; including Compressor inlet and compressor outlet compressor, the compressor is used to recycle the reduction gas to boost the pressure, so that the reduction gas can be recycled, the compressor inlet is connected to the reduced tail gas outlet through a pipeline, and the The outlet of the compressor is connected to the inlet of the reducing gas through a pipeline, and the above-mentioned pipeline is equipped with a check valve for controlling the reverse flow of the reducing gas and a pressure gauge for measuring the inlet and outlet pressure of the compressor; it also includes on-line monitoring for entering the fixed bed reaction The _H2 content of the reducing gas of the device is used to determine whether the system needs to supplement _H2 to make the reduction process run normally. The _H2 gas content is reduced, and _H2 needs to be supplemented from the _H2 inlet. The _H2 content reaches Requirements, stop increasing H ₂ ; H ₂ inlet and N ₂ inlet are respectively connected on the pipeline connecting the compressor outlet and the reducing gas inlet; tail gas outlet is also provided on the pipeline connected to the reduced exhaust gas outlet. Empty the outlet, the system also includes compressor cooling water circulation system, one-way valve to prevent gas backflow, online temperature measurement and pressure measurement and other auxiliary equipment.

The tube side of the fixed bed reactor is equipped with a dimethyl ether synthesis catalyst, and the catalyst after the reduction of the synthesis gas is used for catalytic synthesis reaction under certain pressure and temperature conditions. There is a temperature measuring point in the middle; multiple reaction tubes are distributed in parallel in the fixed bed reactor, the catalyst in the reaction tube exchanges heat with the heat transfer oil outside the reaction tube, and the reducing gas undergoes reduction reaction in the reaction tube. Hydrogen and nitrogen are mixed into a certain proportion of reducing gas in the pipeline, and enter the synthesis tower for catalyst reduction reaction. The hydrogen content in the mixed gas is analyzed online by a hydrogen online analyzer. The temperature control of the fixed bed reactor is heated by a heat transfer oil furnace. The pipeline reaches the shell side of the reactor for heating, the heated heat transfer oil circulates into the heat conduction oil furnace for reheating, the reduction tail gas enters the compressor for pressurization, and circulates into the fixed bed reactor through the check valve. The whole catalyst reduction process is carried out under the conditions of hydrogen content of 0-25%, 0.3-0.5MPa, normal temperature to 270 DEG C, so as to reduce the dimethyl ether synthesis catalyst.

Compared with the prior art, the utility model has the following advantages: the utility model is optimized and integrated on the basis of the traditional catalyst reduction chemical unit, adopts the recycling of inert gas _N2 to dilute _H2 for reduction, without reducing catalyst reduction When the effect is high, N ₂ and H ₂ are saved, and the waste of nitrogen and hydrogen in the catalyst reduction process is greatly reduced. In the methyl ether system, the catalytic synthesis of dimethyl ether by the push forward method is commercially operated.

Description of drawings

Fig. 1 is the utility model one-step catalytic synthesis dimethyl ether catalyst reducing device schematic diagram;

Fig. 2 is _H in the temperature control procedure of the utility model and reduction process Content change figure;

Explanation of reference signs: 1. _H2 inlet, 2. _N2 inlet, 3. Reduction gas inlet, 4. Tail gas outlet after reduction, 5. Check valve, 6. Compressor inlet, 7. Compressor outlet, 8. Tail gas exhaust outlet, 9. Fixed bed reactor, 10. Hydrogen online analyzer, 11. Compressor, 12. Heat transfer oil furnace, 13. Heat transfer oil inlet, 14. Heat transfer oil outlet, 15. Cooling water inlet, 16, Cooling water outlet, 17, pressure gauge, 18, temperature measuring point.

Detailed ways

The content of the present utility model will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Example:

The catalyst reduction device and method for the one-step catalytic synthesis of dimethyl ether in this embodiment utilizes mature chemical equipment units, conducts system reorganization and optimization, and adopts a method of recycling reducing gas, thereby reducing the loss of reducing gas and reducing production costs.

As shown in Figure 1, this embodiment provides a catalyst reduction device for one-step catalytic synthesis of dimethyl ether, including a fixed bed reactor 9, a plurality of reaction tubes are arranged in parallel longitudinally in the fixed bed reactor 9, and the inside of the tubes is equipped with There is a dimethyl ether catalyst, and the outside of the tube is filled with circulating heat transfer oil. A tube at the bottom of the fixed bed reactor 9 is equipped with a temperature measuring point 18, and a thermocouple socket at the bottom is directly inserted into the middle of the tube for temperature measurement. ; The top is provided with a reduction gas inlet 3 connected to the tubes, the bottom is provided with a reduced tail gas outlet 4, two symmetrical heat transfer oil inlets 13 are provided below the side, and a heat transfer oil outlet 14 is provided above the side; For storage and heating of the heat transfer oil, the heat transfer oil is heated in the heat transfer oil furnace 12, and the high temperature heat transfer oil is provided to enter the tube side of the fixed bed reactor to provide the temperature required for the reduction reaction, and enter the fixed bed through the heat transfer oil inlet 13 The shell side of the reactor 9 performs heat exchange to heat the fixed-bed reactor 9, and the heat-conducting oil after heat exchange flows out through the heat-conducting oil outlet 14 on the upper side of the fixed-bed reactor 9, and then flows into the heat-conducting oil furnace 12 through the pipeline for cyclic heating; A compressor 11 comprising a compressor inlet 6 and a compressor outlet 7, the compressor pressurizes the reduced gas so that the reduced gas can be recycled and reused; the compressor 11 near the compressor outlet 7 is provided with There is a cooling water inlet 15, and a cooling water outlet 16 is provided on the compressor 11 close to the compressor inlet 6; the compressor inlet 6 is connected to the reduced tail gas outlet 4 through a pipeline, and the compressor outlet 7 is connected to the reduction gas inlet through a pipeline 3 connections, the above pipelines are equipped with a pressure gauge 17 and a one-way valve 5, the one-way valve 5 is used to control the reverse flow of the reducing gas, the pressure gauge 17 measures the pressure at the inlet and outlet of the compressor 11, and provides power for the reducing gas so that it can circulate Utilize; Also comprise the reduction gas _H content that online monitoring enters fixed-bed reactor 9, determine whether need supplement H with this in the system Make the hydrogen on-line analyzer ₁₀ of normal operation of reduction process, hydrogen on-line analyzer 10 is connected On the pipeline between the compressor outlet 7 and the reducing gas inlet 3; on the pipeline connected between the compressor outlet 7 and the reducing gas inlet 3, _H2 inlet 1 and _N2 inlet 2 are respectively connected; The connected pipeline is also provided with an exhaust gas outlet 8 and related pressure and temperature measurement devices.

In the early stage of the reduction reaction, it is necessary to use _N2 to replace the system to ensure that the oxygen content in the system is low. _N2 inlet 2 is filled with nitrogen, and the compressor 11 is turned on to make the system reach 0.3MPa, and then the tail gas exhaust outlet 8 is opened to discharge the oxygen containing The replacement gas in the system makes the _N2 in the system circulate, and repeats this three times, so that the oxygen content in the system is lower than 0.5%, then opens the _N2 inlet 2, makes the system pressure reach 0.3MPa, turns on the compressor 11, and makes the system The gas in the medium is circulated, and the heat-conducting oil furnace 12 is turned on to heat the fixed-bed reactor 9. When the temperature reaches 50°C, the H ₂ inlet 1 is opened to hydrogenate the entire system, and the catalyst reduction reaction is started, and the hydrogen on-line analyzer 10 is used to carry out on-site monitoring, then the heat conduction oil furnace 12 heats up, and as the reduction proceeds, the _H2 content is kept within a certain range by the hydrogen online analyzer. With the addition of hydrogen, the pressure in the system exceeds 0.5MPa, and the exhaust outlet needs to be opened to discharge the exhaust gas. Stabilize the system pressure; until the reduction reaction is complete; the reduction setting temperature rise program is: from room temperature through 110°C (1h), 140°C (1h), 160°C (3h), 220°C (3h) and 270°C (1h～3h) For reduction, the temperature control program in the heating reduction system and the change of _H2 content during the reduction process in actual operation are shown in Figure 2.

The catalyst used in this example is a bifunctional catalyst for the one-step synthesis of dimethyl ether with the patent number of CN1785519. The fixed bed reactor in this embodiment is the fixed bed reactor designed in the patent application number: 200810218978.X. One-step synthesis of dimethyl ether After the reduction of the catalyst is completed, the dimethyl ether synthesis process is carried out, and the average composition of the synthesis gas is:

V(H ₂ ):V(CO):V(CO ₂ ):V(O ₂ ):V(N ₂ ):V(CH ₄ )=28.63:28.19:29.19:0.06:11.54:2.45, where H ₂ /CO=0.98～1.17, the gas content above _C2 is less than 0.05%, and the synthesis runs continuously. The synthesis results are as follows:

Further, the size of the tubes in the fixed bed reactor 9 in this embodiment can be designed according to needs;

The heat-conducting oil furnace 12 is a related device that can provide heat such as a water boiler or an electric heating jacket;

The _H contained after reducing the exhaust gas outlet 4 can also be recycled;

Compressor cooling water can be tap water or soft water treated by a water softener.

The above detailed description is a specific description of the feasible embodiment of the utility model. This embodiment is not used to limit the patent scope of the utility model. Any equivalent implementation or change that does not deviate from the utility model shall be included in this case within the scope of the patent.

Claims (2)

1. one-step catalytic synthesis gas dimethyl ether catalyst reduction device, it is characterized in that: comprise fixed-bed reactor (9), in this fixed-bed reactor (9), a plurality of reaction tubes of parallel distribution, described fixed-bed reaction There is a temperature measuring point (18) in a tube at the bottom of the device (9), a reducing gas inlet (3) on the top, a reduced exhaust gas outlet (4) on the bottom, and two symmetrical heat transfer oils on the lower side The inlet (13) is provided with a heat transfer oil outlet (14) above the side; A heat transfer oil furnace (12) for storing and heating the heat transfer oil, the heat transfer oil furnace (12) is connected to the fixed bed reactor (9) through the heat transfer oil inlet (13), and the heat transfer oil outlet (14) is connected through a pipeline To heat conduction oil furnace (12); A compressor (11) comprising a compressor inlet (6) and a compressor outlet (7), the compressor inlet (6) is connected to the reduced tail gas outlet (4) through a pipeline, and the compressor outlet (7) Connect with the reducing gas inlet (3) through a pipeline, and the above-mentioned pipeline is equipped with a check valve (5) for controlling the reverse flow of the reducing gas and a pressure gauge ( 17); It also includes on-line monitoring of the reducing gas _H content entering the fixed-bed reactor (9), so as to determine whether the system needs to supplement H ₂ to allow the normal operation of the reduction process on-line hydrogen analyzer (10); On the pipeline that the compressor outlet (7) is connected with the reducing gas inlet (3), also be respectively connected with H ₂ inlet (1) and N ₂ inlet (2); A tail gas evacuation outlet (8) is also provided on the connected pipeline. 2. The one-step catalytic synthesis gas dimethyl ether catalyst reduction device according to claim 1, characterized in that: the heat-conducting oil furnace (12) can also be a superheated steam boiler or an electric heating jacket. the

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