A purification and treatment system for methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas, and heat transfer oil vapor heating

Abstract

The invention discloses a purification treatment system for methanol-to-hydrogen residual liquid, hydrogen-containing waste gas and heat-conducting oil vapor heating, belonging to the technical field of organic waste liquid and waste gas purification. The hydrogen-containing waste gas is sent into the gas holder through the air inlet mechanism and then enters the catalytic combustion device through the air outlet mechanism; the methanol-to-hydrogen residual liquid and methanol are quantitatively pressurized by a metering pump and then enter the vaporizer from the upper opening together with nitrogen, are heated and vaporized by exchanging heat with flue gas, and flow into the catalytic combustion device by gravity; the air is quantitatively pressurized by a Roots blower, enters the catalytic combustion device after being heated by exchanging heat with the flue gas through a heat exchanger; the above three streams enter the catalytic combustion device, and the flue gas after sufficient reaction is discharged after passing through the heat exchanger and the vaporizer successively; the reaction heat of the catalytic combustion device is carried out by the vaporization of the heat-conducting oil between the heat exchange tubes in the first-stage catalytic combustion reaction section, and the second-stage catalytic combustion reaction section is an adiabatic fixed-bed structure, which can deeply purify the flue gas of the first-stage catalytic combustion reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of purification of organic waste liquids and waste gases, in particular to the purification treatment of residual liquid from methanol hydrogen production and hydrogen-containing waste gas, and a heat transfer oil vapor heating system. Background Art

[0002] Methanol and water vapor react through a catalyst under certain temperature and pressure conditions. Under the action of the catalyst, a methanol cracking reaction and a carbon monoxide conversion reaction occur to generate hydrogen and carbon dioxide. This is a multi-component and multi-reaction gas-solid catalytic reaction system. The reaction equations are as follows:

[0003] CH3OH → CO + 2H2

[0004] H2O + CO → CO2 + H2

[0005] CH3OH + H2O → CO2 + 3H2

[0006] The H2 and CO2 generated by the reforming reaction are then separated by pressure swing adsorption (PSA) to obtain high-purity hydrogen. The remaining tail gas (mainly containing hydrogen, carbon dioxide, trace methanol, and a small amount of carbon monoxide) needs to be discharged. At the same time, the subsequent hydrogen-using process equipment will also discharge more or less excess hydrogen containing a large amount of VOCs.

[0007] With the country's emphasis on air pollution control, most regions in China can no longer accept the direct emission of the above gases into the atmosphere. The organic substances and carbon monoxide need to be purified before being discharged. The treatment process is cumbersome and complex, and it will also generate waste liquids and solid wastes that cause secondary pollution.

[0008] In the existing methanol steam reforming hydrogen production technology, since the raw material water is in excess, a large amount of water-containing residual liquid will be generated during the separation of the reformed gas. At the same time, certain side reactions will inevitably occur in the methanol steam reforming reaction, and there will also be impurities in the methanol raw material. These impurities are present in the above-mentioned residual liquid. If all are returned as feed, they will accumulate in the system, thereby poisoning the methanol steam reforming catalyst and shortening its service life. Therefore, the impurity concentration in the reaction system cannot be very high, and the residual liquid must be quantitatively discharged outside the reactor. If directly discharged, it will cause environmental pollution.

[0009] In the existing methanol steam reforming hydrogen production technology, the concentration of hydrogen in the tail gas discharged after separating hydrogen by pressure swing adsorption (PSA) varies from 0% to 90% with the discharge flow rate, and it is discontinuous. It needs to be collected and buffered before continuous output. The molecular weight of hydrogen is 2, and the molecular weight of carbon dioxide is 44. When collecting the pressure swing adsorption tail gas in a container, there is an obvious layering phenomenon. Hydrogen exists at the top of the container, while carbon dioxide is concentrated at the bottom of the container. When it is used as a supply for catalytic combustion reaction, when the hydrogen content is low, less oxygen is consumed. When supplying air at a normal flow rate, oxygen will accumulate in the reactor. When the hydrogen concentration increases, it is extremely easy to form an explosive gas mixture, posing a safety hazard. When the hydrogen content is high, a large amount of oxygen is consumed. When supplying air at a normal flow rate, the reaction in the reactor is incomplete due to lack of oxygen. Excessive hydrogen reacts with carbon monoxide, methanol, and methane under the action of a catalyst to generate VOCs substances of several hundred or even thousands of ppm, seriously exceeding the environmental protection emission standards. In the existing technology that uses catalytic combustion as a heat source, a large amount of flue gas is usually used for dilution to reduce the oxygen and combustible gas content in the reactor, enabling it to operate safely. In this way, the equipment is bulky, the operating efficiency is low, and it is difficult to achieve a purification effect that meets the requirements of environmental protection emission standards. Summary of the Invention

[0010] In view of this, the present invention provides a methanol hydrogen production residual liquid, hydrogen-containing waste gas purification treatment, and heat transfer oil vapor heating system, which provides a complete purification treatment of methanol hydrogen production residual liquid and hydrogen-containing waste gas, can meet the requirements of safety and environmental protection supervision, and at the same time provides a heat source for methanol hydrogen production, facilitating independent construction, and thus being more suitable for practical use.

[0011] In order to achieve the above object, the technical solution of the methanol hydrogen production residual liquid, hydrogen-containing waste gas purification treatment, and heat transfer oil vapor heating system provided by the present invention is as follows:

[0012] The methanol hydrogen production residual liquid, hydrogen-containing waste gas purification treatment, and heat transfer oil vapor heating system provided by the present invention includes a gas holder (1), a Roots blower (2), a heat exchanger (3), a metering pump (4), a vaporizer (5), and a catalytic combustion device (6).

[0013] The catalytic combustion device (6) includes a primary catalytic combustion reaction section (6-14) and a secondary catalytic combustion reaction section (6-7).

[0014] The hydrogen-containing waste gas is sent into the gas holder (1) through an intake mechanism (1-2), and then enters the catalytic combustion device (6) through an outlet mechanism (1-3).

[0015] The methanol hydrogen production residual liquid and methanol are quantitatively pressurized by the metering pump (4) and then enter the vaporizer (5) from the upper opening together with nitrogen. After being heated and vaporized by exchanging heat with flue gas, they flow into the catalytic combustion device (6) by gravity.

[0016] After the air is quantitatively pressurized by the Roots blower (2), it enters the catalytic combustion device (6) after being heated by exchanging heat with the flue gas through the heat exchanger (3).

[0017] The above three streams enter the catalytic combustion device (6). After the flue gas has fully reacted, it passes through the heat exchanger (3) and the vaporizer (5) in sequence and then is vented.

[0018] The reaction heat of the catalytic combustion device (6) is taken out by the vaporization of the heat transfer oil between the heat exchange tubes in the first-stage catalytic combustion reaction section (6-14). The second-stage catalytic combustion reaction section (6-7) is an adiabatic fixed-bed structure, which can deeply purify the flue gas of the first-stage catalytic combustion reaction.

[0019] The methanol-to-hydrogen residue liquid, hydrogen-containing waste gas purification treatment and heat transfer oil vapor heating system provided by the present invention can also be further realized by adopting the following technical measures.

[0020] Preferably, the gas holder (1) is of a vertical lifting structure, including a water tank (1-1) and an air inlet mechanism (1-2), an air outlet mechanism (1-3) connected thereto, a floating drum (1-4) and an exhaust mechanism (1-5) connected thereto;

[0021] Preferably, the water tank (1-1) is a bottomed and lidless cylindrical body, and its lower part has a first opening communicating with the air inlet mechanism (1-2) and a second opening communicating with the air outlet mechanism (1-3);

[0022] Further, the air inlet mechanism (1-2) is an air inlet pipe that passes from the outside of the lower part of the water tank through the water layer to above the water surface inside the water tank and is covered in the floating drum (1-4);

[0023] Further, the air outlet mechanism (1-3) includes a gas guide pipe (1-6) suspended at the top of the floating drum (1-4) and moving together with the floating drum, and an air outlet pipe that passes through the water layer from above the water surface of the water tank to the outside of the lower part of the water tank. At the same time, the gas guide pipe (1-6) is always inside the air outlet pipe when the floating drum moves up and down, so that the air outlet mechanism (1-3) can make the outlet air be a mixed gas from the top layer and the bottom layer of the gas holder in a certain proportion;

[0024] Preferably, the floating drum (1-4) is a bottomless and lidless cylindrical body, and its top is provided with an exhaust mechanism (1-5), which is a gas conduit extending to a position slightly higher than the bottom opening of the floating drum at the bottom of the floating drum. The lower part has an enlarged section with a gas-liquid separation function, and the enlarged section has gas velocity reduction distribution openings. When the floating drum rises and exposes it above the water surface, the gas holder is filled with gas, and the excess gas is discharged through the exhaust mechanism (1-5);

[0025] Preferably, the catalytic combustion device (6) includes a first-stage catalytic combustion reaction section (6-14), a second-stage catalytic combustion reaction section (6-7) and a gas circulation driving section (6-16);

[0026] Preferably, the first-stage catalytic combustion reaction section (6-14) is a closed space formed by an upper tube sheet (6-10), a lower tube sheet (6-15), an outer cylinder, heat exchange tubes provided with a second catalyst filling mechanism (6-12), and a central tube (6-17) for introducing a mixed gas feed, filled with heat-conducting oil. The outer cylinder is provided with a heat-conducting oil vapor outlet (6-11) and a heat-conducting oil liquid inlet (6-13). The catalytic combustion reaction gas passes through the heat exchange tubes provided with the second catalyst filling mechanism (6-12) from bottom to top.

[0027] Furthermore, the heat-conducting oil is selected from one or a mixture of diethylbenzene, diisopropylbenzene, and Dowtherm.

[0028] Furthermore, the second catalyst filling mechanism (6-12) in the heat exchange tubes is a support spring and a plurality of commercially available honeycomb ceramic catalysts with platinum-palladium as the active component for purifying organic waste gas mounted thereon, and the honeycomb ceramic catalysts are separated by inert materials.

[0029] Preferably, the second-stage catalytic combustion reaction section (6-7) includes a first opening (6-5) for introducing fuel, a second opening (6-3) for introducing air, a third opening (6-4) for discharging flue gas, a first catalyst filling mechanism (6-6), and a gas guiding mechanism (6-9).

[0030] Furthermore, a fifth opening (6-2) for introducing hydrogen-containing waste gas and a fourth opening (6-1) for introducing methanol hydrogen production residue and methanol are provided at the inlet end of the first opening (6-5).

[0031] Preferably, a first catalyst filling mechanism (6-6) is provided between the conduit of the first opening (6-5) extending into the container and the outer cylinder, which is a mesh plate for support and commercially available particulate catalysts with platinum-palladium as the active component for purifying organic waste gas filled therein.

[0032] Preferably, the gas guiding mechanism (6-9) is a space surrounded by a diversion tube (6-8), a circular ring, an outer cylinder, a lower flange of the outer cylinder, and an upper tube sheet (6-10), which collects the flue gas discharged from the first-stage catalytic combustion reaction section (6-14) and discharges it through the diversion tube (6-8).

[0033] Furthermore, the diversion tube (6-8) is communicated with the second opening (6-3) for introducing air, so that the flue gas discharged from the first-stage catalytic combustion reaction section (6-14) is mixed with air, and then divided into two streams. One stream passes through the first catalyst filling mechanism (6-6) to complete the second-stage catalytic combustion reaction and then discharges from the catalytic combustion device (6), and the other stream is mixed with fuel and returned to the first-stage catalytic combustion reaction section (6-14).

[0034] Preferably, an opening is provided on the pipe wall of the central pipe (6-17) corresponding to the second opening (6-3) for introducing air, and air is directly inhaled from the second opening (6-3) for introducing air, so as to increase the oxygen content of the inlet gas of the second catalyst filling mechanism (6-12) for the primary catalytic combustion reaction;

[0035] Preferably, the gas circulation driving section (6-16) is an upper-end open container composed of a lower end head, a vertical cylinder body and a flange. An opening is provided on the lower end head for installing a circulation fan (6-18), and the upper flange is connected to the lower tube sheet (6-15);

[0036] Furthermore, the circulation fan (6-18) is a direct-connected fan and is composed of an impeller and a motor.

[0037] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0038] 1. By using a floating roof gas holder to collect intermittently discharged hydrogen-containing waste gas, the gas discharged from the floating roof gas holder comes from the mixed gas at the top and bottom of the container, so that the hydrogen-containing waste gas can supply gas to the catalytic combustion device continuously and evenly, which is convenient for safety control.

[0039] 2. The methanol hydrogen production residue liquid and methanol are driven by a nitrogen gas stream to pass through a vaporizer, and it is easier to exchange heat and vaporize, so that the liquid vaporization is more complete, which is convenient for the catalytic combustion reaction; the continuously introduced nitrogen gas stream makes the catalytic combustion device operate more safely.

[0040] 3. The catalytic combustion device adopts a series-connected two-stage catalytic combustion reaction structure, and catalysts can be preferably selected according to different reaction type requirements. While efficiently realizing the heat energy recovery and supply of the methanol hydrogen production residue liquid and hydrogen-containing waste gas through catalytic combustion reaction, the flue gas emission can meet the requirements of on-line VOCs detection.

[0041] 4. By introducing air through a bypass opening in the central pipe, it is convenient to adjust the oxygen content at the inlets of the two-stage catalytic combustion reaction respectively. With only one air inlet, the whole system is simplified and the operation is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present invention. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0043] Attached Figure 1 is a schematic diagram of the overall structure of the methanol hydrogen production residue liquid, hydrogen-containing waste gas purification treatment and heat transfer oil vapor phase heating system provided by the embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] In view of this, the present invention provides a system for purifying and treating methanol-to-hydrogen residual liquid, hydrogen-containing waste gas, and heat-conducting oil vapor heating, which provides a complete purification and treatment of methanol-to-hydrogen residual liquid and hydrogen-containing waste gas, can meet the requirements of safety and environmental protection supervision, and at the same time provides a heat source for methanol-to-hydrogen production, facilitating independent construction, and thus being more suitable for practical use.

[0045] To further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation manners, structures, features, and effects of a system for purifying and treating methanol-to-hydrogen residual liquid, hydrogen-containing waste gas, and heat-conducting oil vapor heating proposed according to the present invention. In the following description, different "one embodiment" or "embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0046] The term "and / or" in this text is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B is specifically understood as: it can simultaneously include both A and B, A can exist alone, or B can exist alone, and it can possess any one of the above three situations.

[0047] See the attached Figure 1 , in the system for purifying and treating methanol-to-hydrogen residual liquid, hydrogen-containing waste gas, and heat-conducting oil vapor heating provided in the embodiment of the present invention, each reference numeral represents:

[0048] 1. Gas holder - Receives and stores gas, buffers the changes in inlet gas composition and flow rate, and equalizes the outlet gas composition and flow rate. The gas holder 1 has a vertical lifting structure and includes a water tank 1-1 and a floating drum 1-4. The water tank 1-1 is a bottomed and lidless cylindrical body, and its lower part has a first opening communicating with the inlet mechanism 1-2, which is an inlet pipe that passes through the water layer from the outside of the lower part of the water tank to the inside of the water tank and is covered in the floating drum above the water surface; its lower part has a second opening communicating with the outlet mechanism 1-3, which includes a guide pipe 1-6 suspended at the top of the floating drum 1-4 and moving together with the floating drum, and an outlet pipe that passes through the water layer from above the water surface of the water tank to the outside of the lower part of the water tank. At the same time, the guide pipe 1-6 is always inside the outlet pipe when the floating drum moves up and down, so that the outlet mechanism 1-3 can make the outlet gas be a mixed gas from the top layer and the bottom layer of the gas holder in a certain proportion. The floating drum 1-4 is a bottomless and lidless cylindrical body, and its top is provided with an exhaust mechanism 1-5, which is a gas conduit extending to a position slightly higher than the bottom opening of the floating drum at the bottom of the floating drum. The lower part has an enlarged section with a gas-liquid separation function, and the enlarged section has gas velocity-reducing distribution openings. When the floating drum rises and exposes it above the water surface, the gas holder is filled with gas, and the excess gas is discharged through the exhaust mechanism 1-5.

[0049] 2. Roots blower - Compresses air by metering, and is a general mechanical equipment.

[0050] 3. Heat exchanger - Exchanges heat between air and the flue gas discharged from the catalytic combustion device 6 for waste heat recovery.

[0051] 4. Metering pump - Metering and boosting the methanol-to-hydrogen production residue and methanol, and it is a general mechanical equipment.

[0052] 5. Vaporizer - Exchanges heat between the methanol-to-hydrogen production residue and methanol and the flue gas that has been cooled by exchanging heat with air for vaporization and waste heat recovery.

[0053] 6. Catalytic combustion device - The main reactor includes a primary catalytic combustion reaction section 6-14, a secondary catalytic combustion reaction section 6-7, and a gas circulation drive section 6-16.

[0054] The primary catalytic combustion reaction section 6-14 has a constant-temperature fixed-bed structure. Its function is to enable the combustible substances to fully react, and at the same time release a large amount of heat energy, which is carried out by vaporizing the heat transfer oil. A closed space composed of an upper tube sheet 6-10, a lower tube sheet 6-15, an outer cylinder, heat exchange tubes provided with a second catalyst filling mechanism 6-12, and a central tube 6-17 for introducing the mixed gas feed is filled with a heat transfer oil such as diethylbenzene, diisopropylbenzene, Dowtherm, etc. It is provided with a heat transfer oil steam outlet 6-11 and a heat transfer oil liquid inlet 6-13. The second catalyst filling mechanism 6-12 in the heat exchange tubes is a support spring and multiple commercially available honeycomb ceramic catalysts with platinum-palladium as the active component for purifying organic waste gas installed thereon. The honeycomb ceramic catalysts are separated by inert materials such as Raschig rings to strengthen the mixing and heat dissipation, avoiding continuous installation to form high temperatures and burning out the catalyst. The catalytic combustion reaction gas passes through the heat exchange tubes provided with the second catalyst filling mechanism 6-12 from bottom to top. The reactant concentration is high and the heat release is large at the lower part of the catalytic combustion reaction catalyst bed, and it exchanges heat with the liquid-phase heat transfer oil, which helps with heat dissipation.

[0055] The secondary catalytic combustion reaction section 6-7 has an adiabatic fixed-bed structure. Its function is to remove the residual combustible substances and make the gas discharged from the secondary catalytic combustion reaction meet the requirements of VOCs on-line detection. A container with an open lower end composed of an upper end head, a vertical cylindrical body, and a flange includes a first opening 6-5 for introducing fuel, a second opening 6-3 for introducing air, a third opening 6-4 for discharging flue gas, a first catalyst filling mechanism 6-6, and a gas guiding mechanism 6-9. A first catalyst filling mechanism 6-6 is arranged between the conduit of the first opening 6-5 extending into the container and the outer cylinder. It is a perforated plate for support and commercially available particulate catalysts with platinum-palladium as the active component for purifying organic waste gas filled therein. A fifth opening 6-2 for introducing hydrogen-containing waste gas and a fourth opening 6-1 for introducing the methanol-to-hydrogen production residue and methanol are provided at the inlet end of the first opening 6-5.

[0056] The gas guiding mechanism 6-9 is a space enclosed by a diversion pipe 6-8, a circular ring, an outer cylinder, a flange at the lower end of the outer cylinder, and an upper tube sheet 6-10. It collects the flue gas discharged from the first-stage catalytic combustion reaction section 6-14 and discharges it through the diversion pipe 6-8. The diversion pipe 6-8 is connected to the second opening 6-3 for introducing air, so that the flue gas discharged from the first-stage catalytic combustion reaction section 6-14 is mixed with air. Then it is divided into two streams. One stream is discharged from the catalytic combustion device 6 after completing the second-stage catalytic combustion reaction through the first catalyst filling mechanism 6-6, and the other stream is mixed with fuel and returned to the first-stage catalytic combustion reaction section 6-14. An opening is provided on the pipe wall of the central pipe 6-17 at the position corresponding to the second opening 6-3 for introducing air, and air is directly inhaled from the second opening 6-3 for introducing air, increasing the oxygen content of the inlet gas of the second catalyst filling mechanism 6-12 for the first-stage catalytic combustion reaction.

[0057] The function of the gas circulation driving section 6-16 is to inhale liquid or vaporized methanol reforming residual liquid, methanol, hydrogen-containing waste gas, and the flue gas of the first-stage catalytic combustion reaction section 6-14 with air introduced through the central pipe 6-17, pressurize it, and make it pass through the heat exchange tubes provided with the second catalyst filling mechanism 6-12 from bottom to top. It is an upper-open container composed of a lower end head, a vertical cylinder, and a flange. An opening is provided on the lower end head for installing a circulation fan 6-18, and the upper flange is connected to the lower tube sheet 6-15. The circulation fan 6-18 is a direct-connected fan, consisting of an impeller and a motor.

[0058] Process description

[0059] The hydrogen-containing waste gas is sent into the gas holder 1 through the air intake mechanism 1-2, and then enters the catalytic combustion device 6 through the air outlet mechanism 1-3.

[0060] The methanol reforming residual liquid and methanol are quantitatively pressurized by a metering pump 4 and enter the vaporizer 5 from the upper opening together with nitrogen. After being heated and vaporized by exchanging heat with the flue gas, they flow into the catalytic combustion device 6 by gravity.

[0061] After being quantitatively pressurized by a Roots blower 2, air enters the catalytic combustion device 6 after being heated by exchanging heat with the flue gas through a heat exchanger 3.

[0062] The above three streams of materials enter the catalytic combustion device 6, and the flue gas after sufficient reaction is discharged to the atmosphere after passing through the heat exchanger 3 and the vaporizer 5 in sequence.

[0063] The reaction heat of the catalytic combustion device 6 is taken out by vaporizing the heat-conducting oil between the heat exchange tubes of the first-stage catalytic combustion reaction section 6-14. The second-stage catalytic combustion reaction section 6-7 is an adiabatic fixed-bed structure, which can perform in-depth purification treatment on the flue gas of the first-stage catalytic combustion reaction.

[0064] One of the technical problems to be solved by the solution is to continuously and stably supply the hydrogen-containing waste gas, i.e., the pressure swing adsorption desorbed gas from methanol hydrogen production and the exhaust gas from catalytic hydrogenation reaction, with small fluctuations in terms of flow rate and concentration of combustible gas.

[0065] To achieve the above purpose, a gas holder is used to collect and stably discharge the gas.

[0066] One of the functions of the gas holder is to temporarily store the incoming gas. When the incoming gas flow rate is greater than the gas consumption flow rate, the floating roof of the gas holder rises to store the gas. When the incoming gas flow rate is less than the gas consumption flow rate, the floating roof of the gas holder descends to release the gas. By the up and down movement of the floating roof of the gas holder, the relationship between the intermittent incoming gas flow rate and the continuous outgoing gas flow rate is balanced.

[0067] Another function of the gas holder is that the gas discharged from the gas holder is respectively taken from the top and bottom of the floating drum of the gas holder. A guide pipe that can move up and down with the floating drum is inserted into the outlet pipe. By presetting the gap between the guide pipe and the outlet pipe, the gas flow resistance in the guide pipe and between the guide pipe and the outlet pipe is changed, so that the light gas at the top of the floating drum and the heavy gas at the bottom of the floating drum are discharged in a certain proportion, thereby keeping the concentration of the combustible gas discharged from the gas holder fluctuating near the average value.

[0068] In addition to the gas inlet and outlet interfaces, the gas holder is also equipped with a safety discharge port after the gas holder is filled with gas to prevent accidents caused by the floating drum slipping out.

[0069] Another technical problem to be solved by the solution is to realize heat energy recovery and supply, process the residual liquid from methanol hydrogen production, the pressure swing adsorption desorbed gas, and the exhaust gas from catalytic hydrogenation, and finally the discharged gas meets the requirements of VOCs on-line detection.

[0070] To achieve the above purpose, a catalytic combustion device is used. The catalytic combustion device is provided with an inlet for liquid (residual liquid from methanol hydrogen production and methanol), an inlet for hydrogen-containing waste gas (pressure swing adsorption desorbed gas from methanol hydrogen production, exhaust gas from catalytic hydrogenation reaction), an air inlet, and a flue gas outlet after reaction, and has an inlet for heat transfer oil liquid and an outlet for heat transfer oil steam.

[0071] The secondary catalytic combustion process technology is adopted. In the first-stage catalytic combustion reaction section, a constant-temperature fixed-bed structure is used, which is a shell-and-tube type. Heat transfer oils such as diethylbenzene, diisopropylbenzene, and Dowtherm are filled between the tubes. Multiple commercially available honeycomb ceramic catalysts are installed in the tubes. The honeycomb ceramic catalysts are separated by inert materials such as Raschig rings to increase the heat dissipation area and avoid high temperatures caused by continuous installation and burning out of the honeycomb ceramic catalysts. The reaction gas flows upward through the honeycomb ceramic catalyst bed layer. The reaction with high reactant concentration and large heat release occurs in the lower part of the honeycomb ceramic catalyst bed layer, where heat is mainly exchanged with the liquid-phase heat transfer oil, which helps with heat dissipation. The first-stage catalytic combustion reaction section enables the combustible substances to fully react and simultaneously releases a large amount of heat energy, which is carried out by the vaporization of the heat transfer oil. The oxygen content in the mixed gas is controlled below 8%, and the reaction temperature is 150 - 450 °C.

[0072] The secondary catalytic combustion reaction section uses an insulated fixed bed structure. The exhaust gas from the primary catalytic combustion reaction section has a very low concentration of combustible gas after the catalytic combustion reaction, and is safely mixed with the air through a pipeline. After sufficient mixing, a portion of the gas is added with fuel, and after adding an appropriate amount of air, it is sent to the primary catalytic combustion reaction section by a circulating fan, while the other portion of the gas passes through the secondary catalytic combustion reaction section from bottom to top to remove residual combustible matter, so that the gas discharged from the secondary catalytic combustion reaction meets the VOCs online detection requirements. The oxygen content in the mixed gas is controlled at more than 3%, and the reaction temperature is 300-600°C.

[0073] The third technical problem to be solved by the scheme is efficient waste heat utilization. The exhaust gas from the secondary catalytic combustion reaction is first used for air preheating, and then enters the chimney from the bottom and is discharged upward. A shell-and-tube heat exchanger is used to enhance air preheating so that the inlet gas temperature of the secondary catalytic combustion reaction section meets the requirements. A coil is set in the chimney for liquid feed to be vaporized from top to bottom in the nitrogen flow, thereby maximizing waste heat recovery.

[0074] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0075] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system, characterized in that, It includes a gas holder (1), a Roots blower (2), a heat exchanger (3), a metering pump (4), a vaporizer (5) and a catalytic combustion device (6). The catalytic combustion device (6) is successively provided with a gas circulation driving section (6-16), a primary catalytic combustion reaction section (6-14) and a secondary catalytic combustion reaction section (6-7) from bottom to top; The hydrogen-containing waste gas is sent into the gas holder (1) through the intake mechanism (1-2), and then enters the catalytic combustion device (6) through the outlet mechanism (1-3). The methanol hydrogen production residual liquid and methanol are quantitatively pressurized by the metering pump (4) and then enter the vaporizer (5) from the upper opening together with nitrogen. After being heated and vaporized by exchanging heat with the flue gas, they flow into the catalytic combustion device (6) by gravity. The air is quantitatively pressurized by the Roots blower (2), enters the catalytic combustion device (6) after being heated by exchanging heat with the flue gas through the heat exchanger (3). The above three streams enter the catalytic combustion device (6). The flue gas after sufficient reaction passes through the heat exchanger (3) and the vaporizer (5) in sequence and then is discharged. The reaction heat of the catalytic combustion device (6) is carried out by the vaporization of the heat transfer oil between the heat exchange tubes in the primary catalytic combustion reaction section (6-14). The secondary catalytic combustion reaction section (6-7) is an adiabatic fixed bed structure, which can deeply purify the flue gas of the primary catalytic combustion reaction; The primary catalytic combustion reaction section (6-14) includes a central tube (6-17), heat exchange tubes and a first catalyst filling mechanism (6-12); The secondary catalytic combustion reaction section (6-7) includes a first opening (6-5) for introducing fuel, a second opening (6-3) for introducing air, a third opening (6-4) for discharging flue gas, a second catalyst filling mechanism (6-6) and a gas guiding mechanism (6-9); An opening (6-2) for introducing hydrogen-containing waste gas and an opening (6-1) for introducing methanol hydrogen production residual liquid and methanol are arranged at the inlet end of the first opening (6-5); The gas guiding mechanism (6-9) is a space surrounded by a diversion pipe (6-8), a circular ring, an outer cylinder, a lower flange of the outer cylinder and an upper tube plate (6-10), which collects the flue gas discharged from the primary catalytic combustion reaction section (6-14) and discharges it through the diversion pipe (6-8); The diversion pipe (6-8) is communicated with the second opening (6-3) for introducing air, so that the flue gas discharged from the primary catalytic combustion reaction section (6-14) is mixed with air, and then is divided into two streams. One stream is discharged from the catalytic combustion device (6) after completing the secondary catalytic combustion reaction through the second catalyst filling mechanism (6-6), and the other stream is mixed with fuel and returned to the primary catalytic combustion reaction section (6-14); An opening is arranged on the tube wall of the central tube (6-17) corresponding to the second opening (6-3) for introducing air, and air is directly inhaled from the second opening (6-3) for introducing air, so as to increase the oxygen content of the inlet gas of the first catalyst filling mechanism (6-12) for the primary catalytic combustion reaction; The function of the gas circulation driving section (6 - 16) is to inhale the liquid or vaporized methanol hydrogen production residual liquid, methanol, hydrogen-containing waste gas, and the flue gas of the primary catalytic combustion reaction section (6 - 14) with air introduced through the central pipe (6 - 17), pressurize it, and make it pass through the heat exchange pipes provided with the first catalyst filling mechanism (6 - 12) from bottom to top.

2. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 1, characterized in that, The gas holder (1) has a vertical lifting structure, including a water tank (1 - 1) and an air inlet mechanism (1 - 2), an air outlet mechanism (1 - 3) connected thereto, a floating drum (1 - 4), and an exhaust mechanism (1 - 5) connected thereto.

3. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 2, characterized in that, The water tank (1 - 1) is a bottomed and lidless cylindrical body, with a first opening at its lower part communicating with the air inlet mechanism (1 - 2) and a second opening communicating with the air outlet mechanism (1 - 3); The air inlet mechanism (1 - 2) is an air inlet pipe that passes from the outside of the lower part of the water tank through the water layer to above the water surface inside the water tank and is covered by the floating drum. The air outlet mechanism (1 - 3) includes a gas guide pipe (1 - 6) suspended at the top of the floating drum (1 - 4) and moving together with the floating drum, and an air outlet pipe that passes through the water layer from above the water surface of the water tank to the outside of the lower part of the water tank. At the same time, the gas guide pipe (1 - 6) is always inside the air outlet pipe when the floating drum moves up and down. In this way, the air outlet mechanism (1 - 3) can make the outlet gas be a mixed gas from the top layer and the bottom layer of the gas holder in a certain proportion.

4. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 2, characterized in that, The floating drum (1 - 4) is a bottomless and lidless cylindrical body, with an exhaust mechanism (1 - 5) provided at its top, which is a gas conduit extending to a position slightly higher than the bottom opening of the floating drum at the bottom of the floating drum. There is an enlarged section with gas-liquid separation function at the lower part, and the enlarged section has gas velocity reduction distribution openings. When the floating drum rises and exposes above the water surface, the gas holder is filled with gas, and the excess gas is discharged through the exhaust mechanism (1 - 5).

5. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 1, characterized in that, The primary catalytic combustion reaction section (6 - 14) is a closed space formed by an upper tube sheet (6 - 10), a lower tube sheet (6 - 15), an outer cylinder, heat exchange pipes provided with the first catalyst filling mechanism (6 - 12), and a central pipe (6 - 17) for introducing mixed gas feed, filled with heat transfer oil. The outer cylinder is provided with a heat transfer oil steam outlet (6 - 11) and a heat transfer oil liquid inlet (6 - 13). The catalytic combustion reaction gas passes through the heat exchange pipes provided with the first catalyst filling mechanism (6 - 12) from bottom to top; The heat transfer oil is selected from one or a mixture of diethylbenzene, diisopropylbenzene, Dowtherm, etc.; the first catalyst filling mechanism (6 - 12) in the heat exchange pipes is a support spring and multiple commercially available honeycomb ceramic catalysts with platinum-palladium as the active component for organic waste gas purification installed thereon. The honeycomb ceramic catalysts are separated by inert materials.

6. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 1, characterized in that, A second catalyst filling mechanism (6 - 6) is arranged between the conduit of the first opening (6 - 5) extending into the container and the outer cylinder body, which is a mesh plate for support and granular catalysts filled with commercially available platinum-palladium as the active component for organic waste gas purification.

7. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 1, characterized in that, The gas circulation driving section (6 - 16) is an upper-open container composed of a lower end head, a vertical cylinder body, and a flange. The lower end head is provided with an opening for installing a circulation fan (6 - 18), and the upper flange is connected to the lower tube sheet (6 - 15).

8. The methanol-to-hydrogen production residual liquid, hydrogen-containing waste gas purification and heat transfer oil vapor heating system according to claim 7, characterized in that, The circulation fan (6 - 18) is a direct-connected fan, composed of an impeller and a motor.

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