A mercury-free catalyst converter and conversion system

Abstract

The present invention provides a mercury-free catalyst converter and a conversion system, which relates to the technical field of converters. It includes a cylinder body and converter tubes arranged inside the cylinder body. A catalyst is placed inside the tubes. A plurality of temperature measuring rods are arranged inside the cylinder body and inserted into the converter tubes, and a plurality of temperature measuring points are arranged on the temperature measuring rods; a refrigerant circulation heat exchange device is provided on the cylinder body. The refrigerant circulation heat exchange device includes at least two refrigerant inlets and at least two refrigerant outlets, and the refrigerant inlets and the refrigerant outlets are vertically and alternately distributed on both sides of the cylinder body. In the present invention, the reactor outlet pipes and the raw material gas inlet pipes of different converters can be connected through pipelines, and valves are installed on the pipelines. By adjusting the opening and closing of the valves, different converters can be connected in parallel or in series, which can better control the conversion temperature of the converter, and can realize the online switching of the front and rear converters, reduce the loss during the catalyst turnover process, avoid the reduction of production caused by parking, and save labor costs.

Description

Technical Field

[0001] The present invention relates to the technical field of converters, and particularly relates to a mercury-free catalyst converter and a conversion system. Background Art

[0002] As the industry with the largest current mercury consumption, in the process of producing polyvinyl chloride by the calcium carbide acetylene method, a mercury chloride catalyst is generally used. However, mercury chloride is a high-mercury catalyst that is prone to sublimation and loss, resulting in catalyst failure. Moreover, the wastewater containing mercury pollutants generated during the production process is highly toxic, seriously affecting the environment and ecological balance. Therefore, the calcium carbide method polyvinyl chloride production industry has started experiments on mercury-free catalysts.

[0003] There are three main categories of mercury-free catalysts that are currently being tested more: 1. Gold-based catalysts; 2. Copper-based catalysts; 3. Non-gold metal catalysts / non-precious metal catalysts. The specific production steps are as follows: Calcium carbide (calcium carbide CaC2) reacts with water to generate acetylene (C2H2), and acetylene is synthesized with hydrogen chloride (HCl) to produce vinyl chloride monomer (CH3CH2Cl), and then vinyl chloride is polymerized to form polyvinyl chloride -[CH2-CHCl]n- through a chemical reaction method. In the existing production process, gold-based catalysts have a high conversion temperature and good activity, but there are still problems of uneven contact in the process of using gold-based catalysts.

[0004] Chinese Patent with Application No. CN200720032866.6 discloses a novel vinyl chloride synthesis converter, which includes upper and lower conical heads, a conversion bed, and a thermometer; the upper and lower conical heads are provided with a medium inlet and a medium outlet, and a thermometer port is provided on the upper conical head; the conversion bed is a shell-and-tube heat exchanger structure, the tubes are connected to the upper and lower tube sheets by expansion welding, a circular shell surrounds the tubes and is welded to the upper and lower tube sheets, and the tubes and the shell form two mutually isolated cavities, namely a tube side and a shell side. A hot water inlet, a hot water outlet, an exhaust port, and a blowdown port are provided on the shell of the conversion bed, and their positions are all close to the upper and lower tube sheets and are radially distributed with respect to the shell; the tubes are filled with a catalyst, hot water circulates in the shell outside the tubes, and the catalyst in the lower part of the tubes is supported by a catalyst support. However, in this converter, the thermometer used to measure and control the reaction temperature of the conversion bed is set at the upper conical head, while the actual conversion position is at the tubes, and the reaction temperature cannot be accurately displayed.

[0005] The Chinese patent with the application number CN201920334875.3 provides a multi-stage temperature-controlled converter for mercury-free catalytic production of vinyl chloride, which includes a shell, a tube bundle, and a baffle. The tube bundle vertically passes through the baffle, and the baffle is arranged inside the shell and connected to the inner wall of the shell and is radially distributed with the shell. The area of the baffle is smaller than the cross-sectional area of the shell to divide the interior of the shell into multiple connected heat exchange spaces. It is characterized in that a pair of heat exchange medium inlets and heat exchange medium outlets are provided on the shell corresponding to each heat exchange space. This converter can conduct reasonable and effective heat conduction on the tube bundle according to the distribution of the heat transfer of the temperature reaction heat in the tube bundle during the reaction. When the raw material gas entering the tube bundle reacts under the catalysis of the catalyst, the position where the reaction heat is concentrated is determined by using the thermocouple inserted inside the tube bundle, and the change of the temperature in the axial direction of the reaction tube bundle is followed to reasonably control the flow rate of the heat exchange medium for heat exchange and take away the reaction heat. However, multiple baffles are arranged inside this converter to divide it into different heat exchange spaces, and the temperature control structure is cumbersome, which is not conducive to maintenance; and it is inconvenient to carry out the tipping operation or reactivation of the catalyst.

[0006] When the low-mercury / mercury-free catalyst is used in the middle and late stages, that is, the "aging period", or when the use of the low-mercury / mercury-free catalyst does not meet the expectations, it is necessary to carry out the tipping operation or reactivation of the catalyst. When tipping is required, first relieve the pressure and empty the gas in the converter, then carry out nitrogen replacement, and carry out the catalyst tipping and replacement work. When the converter is out of use, the mercury content in the catalyst should be detected, and the tipping and scrapping of the catalyst should be determined according to the mercury content. Generally speaking, tipping the catalyst from the backstage to the front stage is a common practice in the "aging period". From the operation experience of high-efficiency application enterprises, self-tipping in the backstage and self-tipping in the front stage can also be adopted to extend the service time of the catalyst. Therefore, the catalyst tipping work is often accompanied by the out-of-use of the converter, which affects the production work, and the interval of catalyst tipping will have different degrees of influence on the catalyst activity, life, acetylene conversion rate, reaction temperature, bed layer resistance, etc., resulting in catalyst loss.

[0007] The Chinese patent with the application number CN201510364995.4 discloses a conversion device, which adds a converter that can be transformed between the front stage and the back stage, and can be used as a front-stage converter and also as a back-stage converter. When the number of front-stage converters is insufficient, it is used as a front-stage converter, or when the back-stage converter reaches the condition of needing to tip the catalyst, the valve is directly switched to be used as a front-stage converter without tipping the catalyst. However, in the conversion process, adding a converter that can be transformed between the front stage and the back stage as a transfer station, rather than directly switching between the front-stage converter and the back-stage converter, is likely to cause waste of resources.

[0008] Therefore, it is necessary to provide a mercury-free catalyst converter, a conversion system and a method, which can better control the conversion temperature of the converter, and can realize the online switching between the front-stage converter and the back-stage converter, reduce the loss during the catalyst tipping process, avoid the reduction of output caused by parking, and save labor costs. Summary of the Invention

[0009] Based on the above problems, the object of the present invention is to provide a mercury-free catalyst converter and a conversion system.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A mercury-free catalyst converter includes a cylinder body and a plurality of converter tubes arranged inside the cylinder body. A catalyst is placed inside the tubes. A plurality of temperature measuring rods are arranged inside the cylinder body. The temperature measuring rods are inserted into the converter tubes, and a plurality of temperature measuring points are arranged on the temperature measuring rods. The temperature measuring points are used to detect the temperature change inside the tubes and determine the location where the reaction heat is concentrated.

[0012] A refrigerant circulation heat exchange device is provided on the cylinder body. The refrigerant circulation heat exchange device includes at least two refrigerant inlets and at least two refrigerant outlets. The refrigerant inlets and the refrigerant outlets are vertically and alternately distributed on both sides of the cylinder body, and the refrigerant inlets are located below the refrigerant outlets. The refrigerant inlets and the refrigerant outlets are alternately arranged. The lowermost one is the refrigerant inlet, and the uppermost one is the refrigerant outlet, generally showing a situation of low inlet and high outlet. According to the temperature measurement of the temperature measuring points, the refrigerant outlet and the refrigerant inlet can be selected for heat exchange as needed, which helps to better control the conversion temperature of the converter.

[0013] A reactor outlet pipe and a raw material gas inlet pipe are respectively provided at the upper and lower ends of the cylinder body.

[0014] Preferably, the temperature measuring rods include a central temperature measuring rod and edge temperature measuring rods. The central temperature measuring rod is inserted into the converter tube at the central position, and the edge temperature measuring rods are circumferentially distributed around the central temperature measuring rod and inserted into the corresponding converter tubes. There are at least four temperature measuring points.

[0015] Preferably, the upper end of the cylinder body is connected to an upper head through an upper flange, and the lower end of the cylinder body is connected to a lower head through a lower flange. An upper sealing cavity is formed between the upper head and the upper flange, and a lower sealing cavity is formed between the lower head and the lower flange. A plurality of tube through holes are provided on both the upper flange and the lower flange, and the converter tubes are connected through the tube through holes.

[0016] A reactor outlet pipe is provided on the upper head. A raw material gas inlet pipe and a sewage discharge pipe are provided on the lower head.

[0017] The raw material gas (including acetylene) enters the lower sealing cavity from the raw material gas inlet pipe, and then enters the tube bundle. In the tube bundle, vinyl chloride monomer is produced by the catalysis of the catalyst. The unreacted raw material gas continues to contact the catalyst during the upward process to generate vinyl chloride, improving the conversion rate of the raw material gas. The design of the raw material gas entering the converter with low inlet and high outlet enables the raw material gas to start reacting in the lower layer of the converter, and the heat released by the reaction continuously moves upward, which can better maintain the reaction temperature; it is beneficial for the unreacted hydrogen chloride and acetylene gas to preferentially contact the catalyst, reducing the reverse decomposition of vinyl chloride.

[0018] Preferably, the drain pipe is sleeved outside the raw material inlet pipe.

[0019] The raw material gas inlet pipe is L-shaped and one end of the raw material gas inlet pipe extends into the lower sealing cavity, and the other end passes out from the side of the drain pipe.

[0020] Preferably, the end of the raw material gas inlet pipe extending into the lower sealing cavity is higher than the connection of the drain pipe and the lower head. The sleeve design of the drain pipe can prevent sewage from entering the raw material gas inlet pipe.

[0021] Preferably, the lower sealing cavity is filled with activated carbon, and a screen is covered between the activated carbon and the converter tube bundle.

[0022] Preferably, an umbrella cap is fixedly arranged below the screen. The umbrella cap is in a conical shape with an open lower end, and the open end of the umbrella cap faces the end of the raw material gas inlet extending into the lower sealing cavity.

[0023] Preferably, a diaphragm differential pressure liquid level gauge is provided on the cylinder body, and the diaphragm differential pressure liquid level gauges are respectively distributed at the junctions of the cylinder body with the upper head and the lower head.

[0024] Preferably, a number of support ears are fixed on the upper head and the lower head. A number of supports are fixedly connected to the upper part of the outer wall of the cylinder body. The supports are located at two-thirds or three-fourths of the position of the cylinder body.

[0025] Preferably, the catalyst is a gold-based catalyst or a copper-based catalyst.

[0026] The present invention also provides a mercury-free catalyst conversion system, including a first converter and a second converter. Both the first converter and the second converter are the mercury-free catalyst converters described in any one of the above;

[0027] The reactor outlet pipe of the first converter is connected to the raw material gas inlet pipe of the second converter through a switching pipeline; a first valve and a second valve are provided on the switching pipeline;

[0028] The raw material gas inlet pipes of the first converter and the second converter are both connected to the mixer main pipe;

[0029] The reactor outlet pipes of the first converter and the second converter are both connected to the main water washing pipe;

[0030] A third valve and a fourth valve are respectively provided between the reactor outlet pipes of the first converter and the second converter and the main water washing pipe;

[0031] A fifth valve and a sixth valve are provided between the raw material gas inlet pipes of the first converter and the second converter and the main mixer pipe.

[0032] The reactor outlet pipes and the raw material gas inlet pipes of the first converter and the second converter are connected through a switching pipeline. A first valve and a second valve are installed on the switching pipeline. By adjusting the opening and closing of the valves, different converters can be connected in parallel or in series.

[0033] If the first converter and the second converter are to be connected in parallel, the first valve and the second valve are closed, and the other valves remain open. If the first converter and the second converter are to be connected in series and the raw material gas enters from the left end and exits from the right end, the fourth valve and the sixth valve are closed, and the other valves remain open.

[0034] Compared with the prior art, the present invention has the following advantages:

[0035] In the present invention, the raw material gas of the converter enters the converter in a design of low-in and high-out. Considering that the synthesized vinyl chloride has a higher specific gravity than the raw material gas, the raw material gas preferentially contacts the catalyst for reaction; different converters can be switched online between the front stage and the back stage, reducing the loss of the catalyst during the process of turning over the mercury-free catalyst, the impact on the output caused by shutdown, and reducing the labor intensity of the personnel. Especially for the gold-based catalyst, the loss of gold can be greatly reduced and the operation cost can be lowered; in the converter of the present invention, the refrigerant heat exchange has multiple inlets and multiple outlets, which helps to better control the conversion temperature of the converter; a liquid level gauge is added and used as a steam or heptane gas flash tank. As the hot spot of the gold-based catalyst moves upward, the heptane gas phase space of the converter is increased; to reduce the loss of gold in the catalyst during the turning over of the mercury-free catalyst;

[0036] The converter of the present invention reduces the baffle plates in the existing converter, enabling the raw material gas to fully contact the catalyst and improving the conversion rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic structural diagram of a mercury-free catalyst converter of the present invention;

[0038] Figure 2 It is a sectional view of a mercury-free catalyst converter of the present invention;

[0039] Figure 3 It is a schematic structural diagram of the tubes of a mercury-free catalyst converter of the present invention;

[0040] Figure 4 This is a diagram of a mercury-free catalyst conversion system according to the present invention.

[0041] Reference numerals:

[0042] 1 - Cylinder body, 2 - Upper head, 3 - Lower head, 4 - Support ear, 5 - Reactor outlet pipe,

[0043] 6 - Feed gas inlet pipe, 7 - Drain pipe, 8 - Umbrella cap, 9 - Refrigerant inlet, 10 - Refrigerant outlet, 11 - Support, 12 - Upper flange, 13 - Screen, 14 - Converter tube bundle, 15 - Temperature measuring rod, 16 - Catalyst, 17 - Diaphragm differential pressure level gauge; 18 - First converter; 19 - Second converter; 20 - Mixer main pipe;

[0044] 21 - Water washing main pipe; 22 - First valve; 23 - Second valve; 24 - Third valve; 25 - Fourth valve; 26 - Fifth valve; 27 - Sixth valve. Detailed implementation manners

[0045] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0046] In the description of the present application, it should be understood that the orientation or positional relationships indicated by the terms "length", "upper", "lower", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present application.

[0047] As Figures 1-3 shown, the present invention provides a mercury-free catalyst converter for VCM conversion,

[0048] which includes a cylinder body 1. The upper end of the cylinder body 1 is connected to an upper head 2 through an upper flange 12. The upper head 2 is detachably installed on the cylinder body 1. One end of a reactor outlet pipe 5 is fixedly connected to the middle of the upper head 2. An upper sealing cavity is formed between the upper head 2 and the upper flange 12. One end of the reactor outlet pipe 5 leads to the outside of the converter, and the other end enters the upper sealing cavity. A number of converter tube bundles 14 are arranged in the cylinder body 1. A number of through holes corresponding to the tube bundles are provided on the upper flange 12 and are connected to the converter tube bundles 14 through the through holes. The a number of converter tube bundles 14 form a tube bundle. Preferably, the converter tube bundles 14 are evenly arranged inside the cylinder body 1. A catalyst 16 is placed inside the converter tube bundles 14. The catalyst 16 is a gold-based catalyst or a copper-based catalyst. The catalyst 16 is evenly attached to the inner wall of the converter tube bundles 14.

[0049] Inside the cylinder body 1, several temperature measuring rods 15 are provided. The temperature measuring rods 15 are inserted into the converter tubes 14. In this embodiment, eight temperature measuring rods 15 are provided, one of which is a central temperature measuring rod. The central temperature measuring rod is inserted into the converter tube 14 at the central position, and the other seven are edge temperature measuring rods. The edge temperature measuring rods are arranged in a circumferential distribution around the central temperature measuring rod and are all inserted into the corresponding converter tubes 14. At least four temperature measuring points are provided on each temperature measuring rod 15. In addition, the number of temperature measuring rods can be set according to the size of the cylinder body, but it is ensured that the central temperature measuring rod is inserted into the converter tube 14 at the central position and the edge temperature measuring rods are evenly distributed circumferentially.

[0050] The lower end of the cylinder body 1 is connected to the lower head 3 through a lower flange. The lower head 3 is detachably installed at the lower end of the cylinder body 1. A lower sealing cavity is formed between the lower head 3 and the lower flange. Several tube through holes are provided on the lower flange and are connected to the converter tubes 14 through the tube through holes. In the middle of the lower head 3, a raw material gas inlet pipe 6 and a blowdown pipe 7 are provided. The blowdown pipe 7 is a straight pipe. One end of the blowdown pipe 7 opens on the lower head 3 and is connected to the lower sealing cavity, and the other end leads to the outside of the converter. The raw material gas inlet pipe 6 is in an L shape. The diameter of the blowdown pipe 7 is larger than that of the raw material gas inlet pipe 6, and the blowdown pipe 7 is sleeved outside the raw material gas inlet pipe 6. One end of the raw material gas inlet pipe 6 extends into the lower sealing cavity, and the other end passes out from the side of the blowdown pipe 7. The end of the raw material gas inlet pipe 6 extending into the lower sealing cavity is higher than the upper port of the blowdown pipe 7. The sleeve type design of the blowdown pipe 7 can prevent blowdown from entering the raw material gas inlet pipe 6. Activated carbon is filled in the lower head 3. The activated carbon is filled in the cavity of the lower head. The purpose is to make the raw material gas evenly distributed when entering the converter tubes. A screen 13 is covered on the activated carbon. An umbrella cap 8 is provided below the screen 13. The umbrella cap 8 is in the shape of an open cone, and the opening is located above the raw material gas inlet pipe 6, for preventing the catalyst 16 and the activated carbon from falling into the raw material gas inlet pipe 6. The raw material gas inlet pipe 6 is at the lower end of the lower head, and the reactor outlet pipe 5 is at the upper head. The generated vinyl chloride is discharged from the reactor outlet pipe 5 and enters the purification system for treatment after being cooled in the reaction gas cooler.

[0051] A diaphragm differential pressure liquid level gauge 17 is provided at each of the upper and lower parts of the cylinder body 1. The diaphragm differential pressure liquid level gauges 17 are respectively arranged at the junctions of the cylinder body 1 with the upper head 2 and the lower head 3. The diaphragm differential pressure liquid level gauge 17 is used as a steam or heptane gas flash tank. As the hot spot of the gold-based catalyst moves up, the heptane gas phase space in the converter is increased. The diaphragm differential pressure liquid level gauge 17 can increase the heptane liquid layer as the hot spot layer in the converter moves up, and can adjust the height of the heptane liquid layer, so that the reaction heat release in the reaction zone is under the control of the heptane liquid level.

[0052] A refrigerant circulation heat exchange device is also provided on the cylinder body 1. The refrigerant circulation heat exchange device includes a refrigerant inlet 9 and a refrigerant outlet 10. The two refrigerant inlets 9 and the two refrigerant outlets 10 are vertically and alternately distributed on both sides of the cylinder body 1. The arrangement from top to bottom is refrigerant inlet 9 - refrigerant outlet 10 - refrigerant inlet 9 - refrigerant outlet 10, forming a low-in and high-out pattern. In addition, the number of the refrigerant inlets 9 and the refrigerant outlets 10 can be adjusted according to the size of the converter, but it is necessary to ensure that each corresponding refrigerant inlet 9 is located below the refrigerant outlet 10 in the vertical direction and is radially opposite, so as to ensure that the heat exchange medium flows in a low-in and high-out manner. The heat exchange medium flows in from the refrigerant inlet 9, flows around the periphery of the converter tube bundle 14 and then flows out from the refrigerant outlet 10, which is beneficial to the full heat exchange of the tubes in each heat exchange space. The temperature measuring rod 15 cooperates with the refrigerant circulation heat exchange device. The temperature measuring points on the temperature measuring rod 15 are used to detect the temperature change in the tube bundle, determine the place where the reaction heat is concentrated, and then selectively flow the heat exchange medium in from the refrigerant inlet 9 at the corresponding position according to the temperature measurement situation, which helps to better control the conversion temperature of the converter.

[0053] A number of supporting ears 4 are fixedly connected to the upper head 2 and the lower head 3. The upper head 2 and the lower head 3 are dish-shaped heads, and the material is Q345R. A layer of acid-resistant ceramic tiles is lined on the lower head 3. A number of supports 11 are also fixedly connected to the upper part of the outer side of the cylinder body 1. The supports 11 are located at two-thirds or three-fourths of the position of the cylinder body 1.

[0054] The reactor outlet pipes 5 and the raw material gas inlet pipes 6 of different converters can be connected through pipelines, and valves are installed on the pipelines. By adjusting the opening and closing of the valves, different converters can be connected in parallel or in series.

[0055] As Figure 4 shown, the present invention also provides a mercury-free catalyst conversion system, including a first converter and a second converter. The first converter 18 and the second converter 19 are both the above-mentioned mercury-free catalyst converters; the reactor outlet pipe 5 of the first converter 18 is connected to the raw material gas inlet pipe of the second converter 19 through a switching pipeline; a first valve 22 and a second valve 23 are provided on the switching pipeline; the raw material gas inlet pipes of the first converter 18 and the second converter 19 are both connected to the mixer main pipe 20; the reactor outlet pipes 5 of the first converter 18 and the second converter 19 are both connected to the water washing main pipe 21; third valves 24 and fourth valves 25 are respectively provided between the reactor outlet pipes 5 of the first converter 18 and the second converter 19 and the water washing main pipe 21; fifth valves 26 and sixth valves 27 are provided between the raw material gas inlet pipes of the first converter 18 and the second converter 19 and the mixer main pipe 20.

[0056] To connect the first converter 18 and the second converter 19 in parallel, close the first valve 22 and the second valve 23, and keep the other valves open. To connect the first converter 18 and the second converter 19 in series and have the raw material gas enter from the left end and exit from the right end, close the fourth valve 25 and the sixth valve 2, and keep the other valves open.

[0057] Using the above mercury-free catalyst conversion system, the present invention also provides a mercury-free catalyst conversion method.

[0058] When the catalyst 16 uses a gold-based catalyst, the gold-based catalyst has a high conversion temperature and good activity in the existing production process. In the front-stage test, the service time is longer than that of the low-mercury catalyst, but in the back-stage, it is far inferior to the low-mercury catalyst.

[0059] To make better use of the gold-based catalyst, a liquid level gauge is added and used as a steam or heptane gas flash tank. As the hot spot of the gold-based catalyst moves downward, the heptane gas phase space in the converter is increased, that is, the control of the refrigerant liquid level moves downward; to reduce the loss of gold in the catalyst overturned during the turnover of the gold-based catalyst, the front stage can be changed to the back stage, and the back stage can be changed to the front stage. The converter filled with the gold-based catalyst can be switched between the front and back stages;

[0060] In view of the test situation of the gold-based catalyst, it is used independently in a single unit with a gold content of 1‰, and the conversion rate containing acetylene is greater than 3% (it can operate for 3000 - 4000 hours). Then start to connect in series with the back stage (the 1‰ gold-based catalyst that has run for 3000 - 4000 hours, after 24 hours of activation or on-line regeneration). After use in the back stage, the conversion rate containing acetylene is greater than 3% (it can operate for 2000 - 3000 hours if the temperature meets the requirements). At this time, the acetylene conversion rate of the front stage is lower than 85%, and start to switch between the front and back stages for operation (the original front stage needs to be activated or on-line regenerated before switching). The switching between the front and back stages or the series-parallel switching is controlled by opening and closing the valves at each part.

[0061] When the catalyst 16 uses a copper-based catalyst, the usage conditions of the copper-based metal catalyst are not much different from those of the existing low-mercury catalyst. There are more side reactions during use than the low-mercury catalyst. In addition to vinyl chloride synthesis in the converted gas, chloroethane, butadiene, and vinylacetylene are also produced. The copper-based catalyst is also prone to heat and spontaneous combustion when being removed, and it is necessary to introduce hydrogen chloride or a mixture of air and nitrogen for inactivation or passivation, and there is uncertainty in potential safety hazards during removal. When testing the copper-based metal catalyst, the refrigerant heat exchange in the converter adopts two inlets and two outlets to better control the conversion temperature of the converter; the raw material gas should enter the converter from the lower part and exit from the upper part (the raw material gas of the low-mercury catalyst enters from the upper part and exits from the lower part to reduce the sublimation loss of mercury). Considering that the specific gravity of the synthesized vinyl chloride is greater than that of the raw material gas, the raw material gas is preferentially in contact with the catalyst for reaction; like the gold-based catalyst, to reduce the overturned catalyst, the front and back stage converter switching process can be adopted.

[0062] The above are only some embodiments of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these obvious alternative forms all fall within the protection scope of the present invention.

Claims

1. A mercury-free catalyst converter, comprising a cylinder body and a plurality of converter tubes arranged inside the cylinder body, with a catalyst placed inside the tubes, characterized in that: A plurality of temperature measuring rods are arranged inside the cylinder body, the temperature measuring rods are inserted into the converter tubes, and a plurality of temperature measuring points are arranged on the temperature measuring rods; A refrigerant circulation heat exchange device is arranged on the cylinder body, the refrigerant circulation heat exchange device includes at least two refrigerant inlets and at least two refrigerant outlets, the refrigerant inlets and the refrigerant outlets are vertically and alternately distributed on both sides of the cylinder body, and the refrigerant inlets are located below the refrigerant outlets; A reactor outlet pipe and a raw gas inlet pipe are respectively arranged at the upper and lower ends of the cylinder body; The temperature measuring rods include a central temperature measuring rod and edge temperature measuring rods, the central temperature measuring rod is inserted into the converter tube located at the central position, and the edge temperature measuring rods are circumferentially distributed around the central temperature measuring rod and inserted into the corresponding converter tubes; The upper end of the cylinder body is connected to an upper head through an upper flange, and the lower end of the cylinder body is connected to a lower head through a lower flange; An upper sealing cavity is formed between the upper head and the upper flange, and a lower sealing cavity is formed between the lower head and the lower flange; The raw gas inlet pipe is L-shaped and one end of the raw gas inlet pipe extends into the lower sealing cavity; A diaphragm differential pressure liquid level gauge is arranged on the cylinder body, and the diaphragm differential pressure liquid level gauges are respectively distributed at the junctions of the cylinder body with the upper head and the lower head.

2. A mercury-free catalyst converter according to claim 1, characterized in that: A number of tube through holes are arranged on both the upper flange and the lower flange and are connected to the converter tubes through the tube through holes; A reactor outlet pipe is arranged on the upper head; a raw gas inlet pipe and a sewage discharge pipe are arranged on the lower head.

3. A mercury-free catalyst converter according to claim 2, characterized in that: The sewage discharge pipe is sleeved outside the raw gas inlet pipe, The other end of the raw gas inlet pipe passes out from the side of the sewage discharge pipe; the end of the raw gas inlet pipe extending into the lower sealing cavity is higher than the connection of the sewage discharge pipe with the lower head.

4. A mercury-free catalyst converter according to claim 3, characterized in that: Activated carbon is filled in the lower sealing cavity, and a screen is covered on the activated carbon.

5. A mercury-free catalyst converter according to claim 4, characterized in that: An umbrella cap is fixedly arranged below the screen, the umbrella cap is in a conical shape with an open lower end, and the open end of the umbrella cap faces the end of the raw gas inlet pipe extending into the lower sealing cavity.

6. A mercury-free catalyst converter according to claim 3, characterized in that: A number of supporting ears are fixed on the upper head and the lower head; a number of supports are fixedly connected to the upper part of the outer wall of the cylinder body.

7. The mercury-free catalyst converter according to claim 1, characterized in that: The catalyst is a gold-based catalyst or a copper-based catalyst.

8. A mercury-free catalyst conversion system, characterized in that: It includes a first converter and a second converter, and both the first converter and the second converter are mercury-free catalyst converters according to any one of claims 1-7; The reactor outlet pipe of the first converter is connected to the feed gas inlet pipe of the second converter through a switching pipeline; a first valve and a second valve are provided on the switching pipeline; The feed gas inlet pipes of the first converter and the second converter are both connected to the mixer main pipe; The reactor outlet pipes of the first converter and the second converter are both connected to the water washing main pipe; A third valve and a fourth valve are respectively provided between the reactor outlet pipes of the first converter and the second converter and the water washing main pipe; A fifth valve and a sixth valve are provided between the feed gas inlet pipes of the first converter and the second converter and the mixer main pipe.

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