Methanol pyrolysis gas energy system

Abstract

The utility model relates to a methanol pyrolysis gas energy system which comprises a methanol buffer tank, a heat exchanger, a gasification chamber and a pyrolysis reactor which are sequentially connected, a pyrolysis catalyst injection port is formed in the pyrolysis reactor, an outlet of the pyrolysis reactor is connected with an inlet of the heat exchanger, an outlet of the heat exchanger is connected with a condenser, and the bottom of the condenser is connected with a liquid wax collector through a pipeline. An outlet of the condenser is connected with a gas-liquid separator, one end of an outlet of the gas-liquid separator is connected with a methanol buffer tank, the other end of the outlet of the gas-liquid separator is connected with a freezing dryer, an outlet of the freezing dryer is connected with a pyrolysis gas buffer tank, an outlet of the pyrolysis gas buffer tank is connected with a pressure swing adsorption device, and the pressure swing adsorption device is used for purifying pyrolysis gas. And a gas outlet of the pressure swing adsorption device is connected with an energy consumption end. The pyrolysis gas purification device is arranged, so that the heat value of a product can be increased; liquid wax removal is carried out on cracking gas, and pipeline blockage is avoided; methanol is preheated by pyrolysis gas, so that the heat utilization rate is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of clean energy power generation, and particularly relates to a methanol cracking gas energy system. Background Art

[0002] Methanol reforming for hydrogen production can be used for power generation, or the cracking gas can be burned directly for energy supply to replace traditional natural gas energy supply. Methanol is a commonly used chemical raw material, which is simple to obtain. And its final products are carbon dioxide and water, being environmentally friendly. It is an ideal power generation method. For some concentrated industrial parks or large boiler plants, it is more cost-effective to use methanol cracking for hydrogen production to replace natural gas power generation.

[0003] The utility model patent with the publication number of CN209418668U discloses a "methanol cracking instant hydrogen production power generation system". In this patent, methanol in the methanol storage tank is sent into the methanol evaporator through the first delivery pump, and then sent into the jacketed reaction kettle by the methanol evaporator for cracking. The cracking gas is directly sent to the fuel cell to complete the conversion of chemical energy into electrical energy, and the converted electrical energy is supplied to the electrical equipment. The high-temperature methanol cracking gas mainly contains hydrogen and carbon monoxide, and also contains a small amount of unreacted methanol and side reaction product wax. The wax is easy to accumulate in the pipeline, blocking the pipeline and causing too high local pressure, with certain potential safety hazards. More importantly, when the cracking gas is not purified, the hydrogen content in the cracking gas is about 65%, and the carbon monoxide content is about 25% - 30%. In the above patent, the methanol cracking gas is not purified and decontaminated, but directly sent to the fuel cell, which will affect the energy conversion rate. Summary of the Utility Model

[0004] The utility model discloses a methanol cracking gas energy system. By dewaxing and purifying the cracking gas, high-purity hydrogen and carbon monoxide are separated, which can be used to convert into electrical energy or replace natural gas combustion for energy supply, greatly improving the calorific value of the product.

[0005] In order to achieve the above purpose, the technical solution adopted by the utility model is as follows:

[0006] A methanol cracking gas energy system includes a methanol buffer tank, a heat exchanger, a gasification chamber, a cracking reactor, a condenser, a gas-liquid separator, a liquid wax collector, a cold dryer, a cracking gas buffer tank, and a pressure swing adsorption device. The methanol stored in the methanol buffer tank is transported to the heat exchanger by a feed pump. The methanol in the heat exchanger is sent to the gasification chamber to be converted into methanol vapor. The methanol vapor is transported to the cracking reactor. A cracking catalyst injection port is provided on the cracking reactor. The cracking gas generated by the cracking reactor is sent back to the heat exchanger. The cracking gas after heat exchange in the heat exchanger is transported to the condenser. The bottom of the condenser is connected to the liquid wax collector through a pipeline. The outlet of the condenser is connected to the inlet of the gas-liquid separator through a pipeline. One of the outlet ends of the gas-liquid separator is connected to the methanol buffer tank through a pipeline, and the other outlet end of the gas-liquid separator is connected to the cold dryer through a pipeline. The outlet of the cold dryer is connected to the cracking gas buffer tank through a pipeline. The outlet of the cracking gas buffer tank is connected to the pressure swing adsorption device through a pipeline. The pressure swing adsorption device purifies hydrogen and carbon monoxide in the cracking gas through multi-stage pressure swing adsorption of adsorbents. The gas outlet of the pressure swing adsorption device is connected to the energy-consuming end through a pipeline.

[0007] Further, the pressure swing adsorption device includes an intake chamber, an analysis gas compressor, a first analysis gas adsorption tower, a second analysis gas adsorption tower, and a vacuum pump. The intake end of the intake chamber is connected to the cracking gas buffer tank through a pipeline. The outlet end of the intake chamber is connected to the analysis gas compressor through a pipeline. The gas outlet of the analysis gas compressor is connected to the first analysis gas adsorption tower and the second analysis gas adsorption tower respectively through pipelines. The gas outlets of the first analysis gas adsorption tower and the second analysis gas adsorption tower are respectively connected to the intake pipeline of the intake chamber through pipelines. The gas outlets of the first analysis gas adsorption tower and the second analysis gas adsorption tower are also respectively connected to the vacuum pump through pipelines. The outlet of the vacuum pump is communicated with the atmosphere.

[0008] Further, program control valves are installed on the pipelines from the analysis gas compressor to the first analysis gas adsorption tower and the second analysis gas adsorption tower respectively. Program control valves are installed on the intake pipelines from the gas outlets of the first analysis gas adsorption tower and the second analysis gas adsorption tower to the intake chamber respectively. Hydrogen concentration detection devices are also installed on the intake pipelines from the gas outlets of the first analysis gas adsorption tower and the second analysis gas adsorption tower to the intake chamber. Program control valves are installed on the pipelines from the gas outlets of the first analysis gas adsorption tower and the second analysis gas adsorption tower to the vacuum pump respectively.

[0009] Furthermore, a flow acquisition sensor is installed at the liquid outlet end of the methanol buffer tank, temperature sensors are installed inside the heat exchanger, temperature sensors are installed inside the gasification chamber, temperature sensors and pressure sensors are installed inside the cracking reactor, a back pressure valve for regulating pressure is installed on the cracking reactor, a flow acquisition sensor is installed on the connecting pipeline from the cracking reactor to the heat exchanger, a temperature sensor is installed on the pipeline from the heat exchanger to the condenser, a pressure sensor and a pressure relief valve are installed inside the cracked gas buffer tank, and the acquisition data of each of the above sensors are respectively fed back to the control system, and the control system adjusts the flow control, temperature control, and pressure control.

[0010] The methanol cracked gas energy system designed by the present utility model has the following technical advantages:

[0011] (1) A multi-stage pressure swing adsorption device is added to purify the cracked gas to obtain high-purity hydrogen (purity reaching 99.99%) and carbon monoxide (purity reaching 99.99%). Both gases can be combusted and can be used to directly replace natural gas for energy supply;

[0012] (2) A small amount of by-product wax contained in the cracked gas is condensed into liquid wax through the condenser for multi-stage wax liquid recovery, avoiding the problem that high-temperature steam carries wax steam to the low-temperature section for condensation, resulting in the solidification of wax liquid and blocking of the pipeline, causing local overpressure;

[0013] (3) The cracked gas generated by the methanol cracking reactor is sent back to the heat exchanger. While the high-temperature cracked gas is preliminarily cooled through the heat exchanger, the methanol is also preheated, greatly improving the thermal utilization rate;

[0014] (4) When the cracked gas cooled twice through the heat exchanger and the condenser is sent into the gas-liquid separator, a small amount of unreacted methanol is entrained in the cracked gas. The unreacted methanol is removed from the cracked gas through the gas-liquid separator, and the removed methanol is returned to the methanol buffer tank as a raw material again, so that the methanol concentration in the cracked gas sent into the cold dryer is lower than 200 ppm. Description of the Drawings

[0015] Figure 1 It is a schematic diagram of the principle of the methanol cracked gas energy system in the embodiment;

[0016] Figure 2 It is a schematic diagram of the principle of the pressure swing adsorption device.

[0017] Explanation of the reference numerals in the drawings:

[0018] 1. Methanol buffer tank; 2. Heat exchanger; 3. Gasification chamber; 4. Pyrolysis reactor; 5. Condenser; 6. Gas-liquid separator; 7. Liquid wax collector; 8. Cold dryer; 9. Pyrolysis gas buffer tank; 10. Pressure swing adsorption device; 11. Inlet chamber; 12. Analyzed gas compressor; 13. First analyzed gas adsorption tower; 14. Second analyzed gas adsorption tower; 15. Vacuum pump. Detailed implementation mode

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0020] This embodiment discloses a methanol pyrolysis gas energy system, which can be divided into two parts. One part is to obtain pyrolysis gas through methanol pyrolysis, and the other part is to purify the pyrolysis products. As Figure 1 shown, the whole energy system is mainly composed of the following devices: methanol buffer tank 1, heat exchanger 2, gasification chamber 3, pyrolysis reactor 4, condenser 5, gas-liquid separator 6, liquid wax collector 7, cold dryer 8, pyrolysis gas buffer tank 9 and pressure swing adsorption device 10. The methanol buffer tank 1 is used to store methanol, and the prepared methanol is filled into the methanol buffer tank 1 through a filling pipeline. The methanol buffer tank 1, heat exchanger 2, gasification chamber 3, and pyrolysis reactor 4 are connected in sequence.

[0021] The pyrolysis reactor 4 is provided with a pyrolysis catalyst injection port. Before the methanol pyrolysis reaction, it is necessary to fill the methanol pyrolysis catalyst into the pyrolysis reactor 4. The catalyst can be one or more of copper-based catalysts, noble metal catalysts, and nickel-based catalysts. The methanol in the methanol buffer tank 1 is sequentially sent into the heat exchanger 2 and the gasification chamber 3 by a horizontal flow liquid inlet pump, and is converted into high-temperature methanol vapor after heating and sent into the pyrolysis reactor 4 for pyrolysis reaction. It should be noted that the methanol sent into the gasification chamber 3 needs to have been defoamed, which helps to reduce the generation of pyrolysis by-product wax. The pyrolysis reactor 4 is provided with multiple catalyst beds. The methanol gas passes through the catalyst beds from top to bottom. Under the reaction conditions of a temperature of 250°C to 300°C and a pressure of 0.5 to 0.6 MPa, methanol undergoes pyrolysis. The main reaction generates high-temperature pyrolysis gas carbon monoxide and hydrogen, and at the same time, a small amount of wax is generated by side reactions.

[0022] The purification structure of the above cracking products is as follows: The cracked gas generated by the cracking reactor 4 is sent back to the heat exchanger 2, and heat exchange is carried out between the heat exchanger 2 and the methanol raw material ready to enter the gasification chamber 3, so as to achieve the purpose of initially cooling the cracked gas (the temperature of the cracked gas after heat exchange in the heat exchanger 2 drops to 119 °C - 121 °C), and also play a role in preheating the methanol, improving the heat utilization rate. After the cracked gas completes heat exchange in the heat exchanger 2, it is transported to the condenser 5 for further cooling, so that the temperature of the cracked gas drops to 43 °C - 47 °C. During the condensation process, the wax generated by side reactions condenses into liquid wax and is collected in the liquid wax collector 7 through the pipeline at the bottom of the condenser 5. The cracked gas after removing wax is introduced into the gas-liquid separator 6, and the unreacted methanol entrained in the cracked gas is removed by using the gas-liquid separator 6. The removed methanol is sent back to the methanol buffer tank 1 through the pipeline. The cracked gas after removing methanol is sent into the cold dryer 8 for drying treatment, and the dried cracked gas is sent into the cracked gas buffer tank 9. After the above purification treatment, the cracked gas stored in the cracked gas buffer tank 9 has low purity of carbon monoxide and hydrogen, and the carbon monoxide and hydrogen need to be purified by a three-stage pressure swing adsorption device 10 to improve the calorific value of the product.

[0023] The principle of pressure swing adsorption for separating gases adopted in the present utility model is described as follows: By using the selective adsorption of adsorbents for different adsorbates, and the fact that the adsorption capacity of the adsorbent for the adsorbate varies with pressure, under the condition of selective adsorption of the adsorbent, high-pressure adsorption can remove the impurity components in the raw material, and these impurities are desorbed under low pressure to regenerate the adsorbent. The three-stage pressure swing adsorption device improves the surface characteristics of the adsorbent particles by adjusting the pore structure of the copper-loaded adsorbent, so that the adsorbent can adsorb CO under high pressure and desorb and regenerate under low pressure, increasing the concentration of CO. This adsorbent disperses monovalent copper ions in a monolayer on a carrier with a relatively high specific surface area, and realizes adsorption separation by the complexation of copper ions and CO, with high CO adsorption capacity and selectivity. Therefore, through three-stage pressure swing adsorption, by taking appropriate operating conditions for each process and its links respectively, high-purity target gases carbon monoxide (purity reaching 99.99%) and hydrogen (purity reaching 99.99%) can be separated, greatly improving the calorific value of the product.

[0024] The structure of the pressure swing adsorption device 10 in this embodiment is as Figure 2As shown in the figure, it mainly includes an intake chamber 11, an analytical gas compressor 12, a first analytical gas adsorption tower 13, a second analytical gas adsorption tower 14, and a vacuum pump 15. Among them, the intake end of the intake chamber 11 is connected to the pyrolysis gas buffer tank 9 through a pipeline, the outlet end of the intake chamber 11 is connected to the analytical gas compressor 12 through a pipeline, the outlet of the analytical gas compressor 12 is connected to the first analytical gas adsorption tower 13 and the second analytical gas adsorption tower 14 respectively through pipelines, the outlet of the first analytical gas adsorption tower 13 and the outlet of the second analytical gas adsorption tower 14 are respectively connected to the intake pipeline of the intake chamber 11 through pipelines, the outlet of the first analytical gas adsorption tower 13 and the outlet of the second analytical gas adsorption tower 14 are also respectively connected to the vacuum pump 15 through pipelines, and the outlet of the vacuum pump 15 is communicated with the atmosphere. Program-controlled valves are installed on the pipelines from the analytical gas compressor 12 to the first analytical gas adsorption tower 13 and the second analytical gas adsorption tower 14 respectively, program-controlled valves are installed on the intake pipelines from the outlet of the first analytical gas adsorption tower 13 and the outlet of the second analytical gas adsorption tower 14 to the intake chamber 11 respectively, hydrogen concentration detection devices are also installed on the intake pipelines from the outlet of the first analytical gas adsorption tower 13 and the outlet of the second analytical gas adsorption tower 14 to the intake chamber 11, and program-controlled valves are installed on the pipelines from the outlet of the first analytical gas adsorption tower 13 and the outlet of the second analytical gas adsorption tower 14 to the vacuum pump 15 respectively.

[0025] The above of the present utility model mainly gives the connection relationships of the various devices in the entire energy system. Corresponding control valves are respectively provided on the connecting pipelines of the various devices. The entire energy system also includes a sampling system and a control system. According to the data collected by the sampling system and fed back to the control system, the control system controls the start and stop of the valves and the corresponding devices on the various pipelines. The sampling system mainly involves flow rate acquisition control, temperature acquisition control, and pressure acquisition control. The installation positions of the various acquisition sensors are described as follows: a flow rate acquisition sensor is installed at the liquid outlet end of the methanol buffer tank 1, a temperature sensor is installed inside the heat exchanger 2, a temperature sensor is installed inside the gasification chamber 3, a temperature sensor and a pressure sensor are installed inside the pyrolysis reactor 4, a back pressure valve for adjusting pressure is also installed on the pyrolysis reactor 4, a flow rate acquisition sensor is installed on the connecting pipeline from the pyrolysis reactor 4 to the heat exchanger 2, a temperature sensor is installed on the pipeline from the heat exchanger 2 to the condenser 5, and a pressure sensor and a pressure relief valve are installed inside the pyrolysis gas buffer tank 9. Among them, the condenser 5, the gas-liquid separator 6, and the cold dryer 8 each have an independent adjustable control system.

[0026] Although the embodiments of the present utility model have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present utility model. The scope of the present utility model is defined by the appended claims and their equivalents.

Claims

1. A methanol cracking gas energy system, characterized by: The device comprises a methanol buffer tank, a heat exchanger, a vaporization chamber, a cracking reactor, a condenser, a gas-liquid separator, a liquid wax collector, a cold dryer, a cracking gas buffer tank, and a pressure swing adsorption device. The methanol stored in the methanol buffer tank is transported to the heat exchanger through a liquid inlet pump. The methanol in the heat exchanger is sent to the vaporization chamber to be converted into methanol vapor. The methanol vapor is transported to the cracking reactor. The cracking reactor is provided with a cracking catalyst injection port. The cracking gas generated in the cracking reactor is returned to the heat exchanger. The cracking gas after heat exchange in the heat exchanger is transported to the condenser. The bottom of the condenser is The outlet of the condenser is connected to the inlet of the gas-liquid separator through a pipeline, one of the outlet ends of the gas-liquid separator is connected to the methanol buffer tank through a pipeline, and the other outlet end of the gas-liquid separator is connected to the cold dryer through a pipeline, the outlet of the cold dryer is connected to the cracking gas buffer tank through a pipeline, and the outlet of the cracking gas buffer tank is connected to the pressure swing adsorption device through a pipeline. The pressure swing adsorption device purifies hydrogen and carbon monoxide in the cracking gas through multi-stage pressure change of the adsorbent, and the gas outlet of the pressure swing adsorption device is connected to the energy consumption end through a pipeline.

2. A methanol cracking gas energy system according to claim 1, characterized in that: The pressure swing adsorption device comprises an air inlet chamber, a decomposition gas compressor, a first decomposition gas adsorption tower, a second decomposition gas adsorption tower and a vacuum pump. The air inlet end of the air inlet chamber is connected to the cracking gas buffer tank through a pipeline, the air outlet end of the air inlet chamber is connected to the decomposition gas compressor through a pipeline, the air outlet of the decomposition gas compressor is connected to the first decomposition gas adsorption tower and the second decomposition gas adsorption tower respectively through pipelines, the air outlet of the first decomposition gas adsorption tower and the air outlet of the second decomposition gas adsorption tower are respectively connected to the air inlet pipeline of the air inlet chamber through pipelines, the air outlet of the first decomposition gas adsorption tower and the air outlet of the second decomposition gas adsorption tower are also respectively connected to the vacuum pump through pipelines, and the outlet of the vacuum pump is connected to the atmosphere.

3. A methanol cracking gas energy system according to claim 2, characterized in that: Programmable valves are installed on the pipelines from the analytical gas compressor to the first analytical gas adsorption tower and the second analytical gas adsorption tower, respectively; programmable valves are installed on the air inlet pipelines from the air outlet of the first analytical gas adsorption tower and the air outlet of the second analytical gas adsorption tower to the air inlet chamber, respectively; a hydrogen concentration detection device is also installed on the air inlet pipelines from the air outlet of the first analytical gas adsorption tower and the air outlet of the second analytical gas adsorption tower to the air inlet chamber, and programmable valves are installed on the pipelines from the air outlet of the first analytical gas adsorption tower and the air outlet of the second analytical gas adsorption tower to the vacuum pump, respectively.

4. A methanol cracking gas energy system according to claim 1, characterized in that: A flow acquisition sensor is installed at the liquid outlet of the methanol buffer tank, a temperature sensor is installed in the heat exchanger, a temperature sensor is installed in the gasification chamber, a temperature sensor and a pressure sensor are installed in the cracking reactor, a back pressure valve for adjusting the pressure is installed in the cracking reactor, a flow acquisition sensor is installed on the connecting pipeline from the cracking reactor to the heat exchanger, a temperature sensor is installed on the pipeline from the heat exchanger to the condenser, a pressure sensor and a pressure relief valve are installed in the cracking gas buffer tank, and the collected data of the above sensors are respectively fed back to the control system, which adjusts the flow control, temperature control and pressure control.

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