An on-line catalyst filling system for a urea catalytic hydrolysis reactor and a filling method thereof

Abstract

The present application relates to urea hydrolysis process technical field, especially to a kind of catalyst online filling system and filling method for urea catalytic hydrolysis reactor;Including catalyst dissolving filling tank, urea catalytic hydrolysis reactor, hydrophobic pipe, filling valve, filling pipe, balance valve and balance pipe;The catalyst dissolving filling tank is arranged at the upper end of the urea catalyst reactor, and the height difference between the catalyst dissolving filling tank and urea catalyst reactor is not less than one meter;The catalyst online filling method for urea catalytic hydrolysis reactor involved in the present application can add catalyst online when catalytic hydrolysis reactor is normally operated under pressure, and the system realizes catalyst solution filling by gravity through height difference design, simple structure, high reliability, can ensure that urea catalytic hydrolysis system is not interrupted and smoothly operated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of urea hydrolysis process, and in particular to a catalyst online filling system for a urea catalytic hydrolysis reactor and a filling method thereof. BACKGROUND

[0002] Early SCR denitration reductant in power industry generally uses liquid ammonia. According to the requirements of safety regulations, the liquid ammonia storage tank is a major hazard source when the storage volume is greater than 10 m3. With the improvement of safety requirements in China, many power plants are actively carrying out major hazard source management of liquid ammonia tank area, changing the liquid ammonia denitration reductant to urea hydrolysis ammonia process to completely eliminate safety hazards.

[0003] The urea hydrolysis ammonia process is divided into ordinary hydrolysis and catalytic hydrolysis. The catalytic hydrolysis process is favored by more and more users due to its fast hydrolysis reaction speed, high urea utilization rate, low reaction temperature, and small corrosion to the system. The main difference between the urea catalytic hydrolysis process and the ordinary hydrolysis process is that a catalyst is added to the urea hydrolysis reactor to promote the rate of urea hydrolysis reaction.

[0004] Generally, a set of catalyst filling system is provided for urea catalytic hydrolysis process. Because the urea hydrolysis reactor generates high working pressure during normal operation, the catalyst is generally added offline, that is, before the urea catalytic hydrolysis system starts, the catalyst is dissolved in the catalyst dissolving tank under the action of the stirrer with demineralized water, and then the catalyst solution is pumped into the urea catalytic hydrolysis reactor. This catalyst dosing method has certain problems, for example, when the catalyst in the hydrolysis reactor is lost with the system blowdown, the urea hydrolysis rate decreases, but the hydrolysis system cannot be stopped, which will affect the operation of the boiler SCR denitration system. SUMMARY

[0005] To achieve the above object, the present application provides the following technical scheme: a catalyst online filling system for a urea catalytic hydrolysis reactor, comprising a catalyst dissolving and filling tank, a urea catalytic hydrolysis reactor, a hydrophobic pipe, a filling pipe, a balance valve and a balance pipe; the catalyst dissolving and filling tank is arranged at the upper end of the urea catalyst reactor, and the height difference between the catalyst dissolving and filling tank and the urea catalyst reactor is not less than one meter;

[0006] The upper end of the filling pipe is connected with the catalyst dissolving and filling tank, and the lower end of the filling pipe is connected with the urea catalytic hydrolysis reactor; the filling pipe is provided with a filling valve; the upper end of the filling pipe is connected with the bottom of the catalyst dissolving and filling tank, and the lower end of the filling pipe is connected with a position below the hydrolysis liquid level of the urea catalytic hydrolysis reactor;

[0007] The upper end of the hydrophobic pipe is connected with the catalyst dissolving filling tank, and the lower end of the hydrophobic pipe is connected with the urea catalytic hydrolysis reactor; the upper end of the hydrophobic pipe is connected with a position above the upper catalyst dissolving surface of the catalyst dissolving filling tank.

[0008] One side of the urea catalytic hydrolysis reactor is provided with a steam inlet.

[0009] The upper end of the balance pipe is connected with the catalyst dissolving filling tank, and the lower end of the balance pipe is connected with the urea catalytic hydrolysis reactor; the balance valve is arranged on the balance pipe; the upper end of the balance pipe is connected with the top end of the catalyst dissolving filling tank, and the lower end of the balance pipe is connected with the top end of the urea catalytic hydrolysis reactor.

[0010] Preferably, the bottom of the catalyst dissolving filling tank is in a reverse conical structure or a circular arc structure.

[0011] Preferably, the lower end of the catalyst dissolving filling tank is provided with a flushing pipe, and the lower end of the flushing pipe is connected with a wastewater tank; the flushing valve is arranged on the flushing pipe.

[0012] Preferably, the hydrophobic pipe is provided with a hydrophobic valve and a flow meter.

[0013] Preferably, the hydrophobic valve, the filling valve, the balance valve and the flushing valve are manual valves or electric valves.

[0014] Preferably, the filling pipe should be inclined downward, and the slope is not less than 5%.

[0015] Preferably, the filling pipe should not have a bending section.

[0016] Preferably, the filling pipe should not have an upward section.

[0017] Preferably, the filling pipe should not have a horizontal section.

[0018] Preferably, when the hydrophobic valve, the filling valve, the balance valve and the flushing valve are manual valves, and the flow meter is a mechanical type, the filling process needs to be manually operated.

[0019] Preferably, when the hydrophobic valve, the filling valve, the balance valve and the flushing valve are electric valves, and the flow meter is an electronic type, the controller can be used to automatically operate according to the set opening sequence and time interval, so as to realize automatic filling.

[0020] Preferably, the filling pipe should be inclined downward, and the slope is not less than 5%, the filling pipe should not have a bending section, an upward section or a horizontal section.

[0021] A method for online filling of a catalyst in a urea catalytic hydrolysis reactor, wherein the implementation process is as follows:

[0022] Step one: before starting, all valves are in the closed state;

[0023] Step two: the urea catalytic hydrolysis reactor adds the same amount of catalyst as the amount of pollution to the catalyst dissolving filling tank after each pollution, and seals the catalyst dissolving filling tank after adding the catalyst;

[0024] Step three: open the hydrophobic valve, measure by the flow meter, inject the same amount of hydrophobic as the catalyst into the catalyst dissolving filling tank through the hydrophobic pipe, dissolve the catalyst into a catalyst solution with a concentration of 50%, and then close the hydrophobic valve;

[0025] Step four: open the filling valve, at this time, because the pressure in the urea catalytic hydrolysis reactor is higher than the pressure in the catalyst dissolving filling tank, the high-pressure gas in the urea catalytic hydrolysis reactor enters the bottom of the catalyst dissolving filling tank through the filling pipe, generates bubbles in the catalyst solution, and stirs the catalyst solution to dissolve fully;

[0026] Step five: after the catalyst dissolving filling tank is fully inflated, open the balance valve, and the catalyst dissolving filling tank and the urea catalytic hydrolysis reactor form a communicating vessel under the connection of the balance pipe and the filling pipe, and the catalyst solution in the catalyst dissolving filling tank flows into the urea catalytic hydrolysis reactor through the filling pipe under the action of gravity;

[0027] Step six: after the catalyst solution is filled, close the filling valve and the balance valve, open the hydrophobic valve again, fill a certain amount of hydrophobic into the catalyst dissolving filling tank to absorb the ammonia gas in the catalyst dissolving filling tank, open the flushing valve after sufficient absorption, and discharge the ammonia water solution into the wastewater tank through the flushing pipe, and close the flushing valve after discharging.

[0028] Beneficial effects: compared with the prior art, the urea catalytic hydrolysis reactor catalyst online filling method disclosed by the application can add catalyst online when the catalytic hydrolysis reactor is normally operated under pressure, the system realizes catalyst solution filling through gravity by using a height difference, the structure is simple, the reliability is high, and the uninterrupted and stable operation of the urea catalytic hydrolysis system can be ensured. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is a structural schematic diagram of the application.

[0030] In the figure: 1, catalyst dissolving filling tank; 2, urea catalytic hydrolysis reactor; 3, hydrophobic pipe; 4, hydrophobic valve; 5, flow meter; 6, filling valve; 7, filling pipe; 8, balance valve; 9, balance pipe; 10, flushing valve; 11, flushing pipe; 12, wastewater tank; 13, steam inlet. EMBODIMENT

[0031] The technical solutions of the patent will be further described in detail in combination with specific embodiments. Embodiments

[0032] Please refer to the drawings in the specification, in the embodiment of the application, a catalyst online filling method for urea catalytic hydrolysis reactor, comprising a catalyst dissolving and filling tank 1, a urea catalytic hydrolysis reactor 2, a hydrophobic pipe 3, a hydrophobic valve 4, a flow meter 5, a filling valve 6, a filling pipe 7, a balance valve 8, a balance pipe 9, a flushing valve 10, a flushing pipe 11 and a waste water tank 12.

[0033] One side of the urea catalytic hydrolysis reactor 2 is provided with a steam inlet 13, and the urea catalytic hydrolysis reactor 1 should be at least one meter higher than the urea catalytic hydrolysis reactor 2 in vertical height, the bottom of the catalyst dissolving and filling tank 1 is connected to the hydrolysis liquid surface of the urea catalytic hydrolysis reactor 2 through the filling pipe 7, the filling valve 6 is arranged on the filling pipe 7 for controlling the opening and closing of the filling pipe 7; the filling valve 6 adopts a manual valve, and can also adopt an electric valve; all pipe sections of the filling pipe 7 should be vertical or inclined downward, the slope should not be less than 5%, and there should be no bending, upward or horizontal section, so as to facilitate the flow of catalyst solution into the urea catalytic hydrolysis reactor 2;

[0034] The catalyst dissolving and filling tank 1 is inverted conical or circular arc bottom, which avoids catalyst solution residue.

[0035] The catalyst dissolving and filling tank 1 is inverted conical or circular arc bottom, which avoids catalyst solution residue.

[0036] The catalyst dissolving and filling tank 1 is inverted conical or circular arc bottom, which avoids catalyst solution residue.

[0037] The bottom of the catalyst dissolving and filling tank 1 is connected to the waste water tank 12 through a flushing pipe 11 for waste water discharge after flushing; the flushing pipe 11 is provided with a flushing valve 10 for controlling the opening and closing of the flushing pipe; the flushing valve 10 adopts a manual valve, and can also adopt an electric valve.

[0038] The catalyst online filling method for urea catalytic hydrolysis reactor:

[0039] Before starting, all valves are in the closed state.

[0040] The urea catalytic hydrolysis reactor 2 adds 50% of the catalyst of the pollution amount into the catalyst dissolving filling tank 1 according to the pollution amount after each pollution, and seals the catalyst dissolving filling tank 1 after adding the catalyst;

[0041] The hydrophobic valve 4 is opened, the hydrophobic liquid equal to the catalyst is injected into the catalyst dissolving filling tank 1 through the hydrophobic pipe 3 by using the flowmeter 5 to measure, the catalyst is dissolved into the catalyst solution with a concentration of 50%, and then the hydrophobic valve 4 is closed;

[0042] The filling valve 6 is opened, at this time, because the pressure in the urea catalytic hydrolysis reactor 2 is higher than the pressure in the catalyst dissolving filling tank 1, the high-pressure gas in the urea catalytic hydrolysis reactor 2 enters the bottom of the catalyst dissolving filling tank 1 through the filling pipe 7, and the gas bubbles are generated in the catalyst solution to agitate the catalyst solution to be fully dissolved;

[0043] After the aeration is completed, the balance valve 8 is opened, the catalyst dissolving filling tank 1 and the urea catalytic hydrolysis reactor 2 form a communicating vessel under the connection of the balance pipe 9 and the filling pipe 7, and the catalyst solution in the catalyst dissolving filling tank 1 flows into the urea catalytic hydrolysis reactor 2 under the action of gravity;

[0044] After the catalyst solution is filled, the filling valve 6 and the balance valve 8 are closed, the hydrophobic valve 4 is opened again, a certain amount of hydrophobic liquid is filled into the catalyst dissolving filling tank 1 to absorb the ammonia gas in the catalyst dissolving filling tank 1, the flushing valve 10 is opened after the ammonia gas is fully absorbed, the waste liquid is discharged into the waste water tank 12 through the flushing pipe 11, and then the flushing valve 10 is closed;

[0045] The urea catalytic hydrolysis reactor with the online catalyst filling method can add the catalyst online when the catalytic hydrolysis reactor is normally operated under pressure, the system realizes the catalyst solution filling through the gravity action by using the height difference design, the structure is simple, the reliability is high, and the uninterrupted and stable operation of the urea catalytic hydrolysis system can be ensured.

[0046] The above is only the preferred embodiment of the present application, and it should be pointed out that for those skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which should be regarded as the protection range of the present application, and these will not affect the effect and practicality of the present application.

Claims

1. An online catalyst dosing system for a urea catalytic hydrolysis reactor, characterized in that: It includes a catalyst dissolution and injection tank (1), a urea catalytic hydrolysis reactor (2), a condensate drain pipe (3), an injection pipe (7), a balance valve (8), and a balance pipe (9); the catalyst dissolution and injection tank (1) is located at the upper end of the urea catalytic hydrolysis reactor (2), and the height difference between the catalyst dissolution and injection tank (1) and the urea catalytic hydrolysis reactor (2) is not less than one meter; The upper end of the injection pipe (7) is connected to the catalyst dissolution injection tank (1), and the lower end of the injection pipe (7) is connected to the urea catalytic hydrolysis reactor (2); an injection valve (6) is provided on the injection pipe (7); the upper end of the injection pipe (7) is connected to the bottom of the catalyst dissolution injection tank (1), and the lower end of the injection pipe (7) is connected to a position below the hydrolysis liquid surface of the urea catalytic hydrolysis reactor (2); The upper end of the hydrophobic pipe (3) is connected to the catalyst dissolution and injection tank (1), and the lower end of the hydrophobic pipe (3) is connected to the urea catalytic hydrolysis reactor (2); the upper end of the hydrophobic pipe (3) is connected to the position above the catalyst dissolution surface on the catalyst dissolution and injection tank (1); A steam inlet (13) is provided on one side of the urea catalytic hydrolysis reactor (2); The upper end of the balance pipe (9) is connected to the catalyst dissolution and injection tank (1), and the lower end of the balance pipe (9) is connected to the urea catalytic hydrolysis reactor (2); the balance pipe (9) is provided with the balance valve (8); the upper end of the balance pipe (9) is connected to the top of the catalyst dissolution and injection tank (1), and the lower end of the balance pipe (9) is connected to the top of the urea catalytic hydrolysis reactor (2); The catalyst dissolution and injection tank (1) is provided with a flushing pipe (11) at its lower end; the lower end of the flushing pipe is connected to a wastewater tank (12); and a flushing valve (10) is provided on the flushing pipe (11). The drain pipe (3) is equipped with a drain valve (4) and a flow meter (5).

2. The online catalyst dosing system for a urea catalytic hydrolysis reactor according to claim 1, characterized in that: The bottom of the catalyst dissolution and injection tank (1) has an inverted conical or arc-shaped structure.

3. The online catalyst dosing system for a urea catalytic hydrolysis reactor according to claim 1, characterized in that: The flow meter (5) is a mechanical flow meter or an electronic flow meter.

4. The online catalyst dosing system for a urea catalytic hydrolysis reactor according to claim 1, characterized in that: The filling pipe (7) should be installed at an angle downwards with a slope of not less than 5%.

5. A method for an online catalyst addition system for a urea catalytic hydrolysis reactor as described in claim 1, characterized in that: The implementation process is as follows: Step 1: Before starting, all valves must be closed; Step 2: After each discharge, the urea catalytic hydrolysis reactor (2) adds catalyst to the catalyst dissolution and injection tank (1) according to the discharge volume. After adding the catalyst, the catalyst dissolution and injection tank (1) is sealed with a lid. Step 3: Open the drain valve (4), use the flow meter (5) to measure, and inject the same amount of condensate as the catalyst into the catalyst dissolution and injection tank (1) through the drain pipe (3) to dissolve the catalyst into a catalyst solution with a concentration of 50%. Then close the drain valve (4). Step 4: Open the injection valve (6). At this time, since the pressure inside the urea catalytic hydrolysis reactor (2) is higher than the pressure inside the catalyst dissolution injection tank (1), the high-pressure gas inside the urea catalytic hydrolysis reactor (2) enters the bottom of the catalyst dissolution injection tank (1) through the injection pipe (7), generating bubbles in the catalyst solution and stirring the catalyst solution to fully dissolve. Step 5: After the catalyst dissolution and filling tank is fully aerated, open the balance valve (8). With the balance pipe (9) and filling pipe (7) connected, the catalyst dissolution and filling tank (1) and the urea catalytic hydrolysis reactor (2) form a communication vessel. The catalyst solution in the catalyst dissolution and filling tank (1) flows into the urea catalytic hydrolysis reactor (2) under the action of gravity through the filling pipe 7. Step 6: After the catalyst solution is added, close the adding valve (6) and the balance valve (8), open the condensate valve (4) again, and fill the catalyst dissolution adding tank (1) with a certain amount of condensate to absorb the ammonia gas in the catalyst dissolution adding tank (1). After sufficient absorption, open the flushing valve (10) and discharge the ammonia solution into the wastewater tank (12) through the flushing pipe (11). After discharge, close the flushing valve (10).

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