CN103216819B - Vaporizing cooling oxygen-eliminating device pressure diffuses control method and system thereof - Google Patents

Abstract

The invention provides a kind of novel Vaporizing cooling oxygen-eliminating device pressure and diffuse control method and system thereof, control system comprises oxygen-eliminating device, oxygen-eliminating device is provided with pressure unit, PLC and diffusion valve, described pressure unit, diffusion valve are connected with PLC respectively, pressure unit is for measuring the pressure of oxygen-eliminating device, diffusion valve on described oxygen-eliminating device takes two pneumatic cut-off valves, and PLC is used for the switch of Stress control two pneumatic cut-off valves recorded by pressure unit.The nominal diameter of described two pneumatic cut-off valves small one and large one.Beneficial effect of the present invention: utilize pneumatic cut-off valve valve opening to close the fast feature of valve events, two pneumatic cut-off valve step control are adopted to diffuse oxygen-eliminating device pressure, solve the problem that Vaporizing cooling oxygen-eliminating device diffuses the too fast Stress control shakiness of rear pressure drop, strengthen deaerating effect, increase Steam Recovery time and evaporated flue life-span simultaneously.

Description

Evaporative cooling deaerator pressure release control method and system

technical field

The invention relates to a steelmaking process in the metallurgical industry, in particular to a pressure release control method and system for a vaporization cooling deaerator.

Background technique

In the converter steelmaking process, the vaporization cooling system is an important link to ensure the cooling of the fume hood. It can also recover heat to generate steam during the converter steelmaking process, reducing the production cost of the enterprise. The life of the vaporization flue is one of the important indicators for the assessment of the vaporization cooling system. To ensure the life of the vaporization flue, the oxygen content of the flue circulating cooling water must be reduced, and the deaerator is the key equipment for the flue circulating cooling water. The deaerator relies on steam to heat the circulating cooling water. Generally, it is advisable to control the pressure inside the deaerator at 0.2MPa~0.3MPa, and control the water temperature in the deaerator at about 131°C. Therefore, the pressure control in the deaerator becomes the key to the deaeration effect.

With reference to shown in Fig. 1, existing vaporization cooling deaerator pressure release control system comprises deaerator 1, and deaerator 1 is provided with pressure transmitter 2, PLC controller 3 and electric release valve 6, and described pressure The transmitter 2 and the electric relief valve 6 are respectively connected with the PLC controller 3 . In the normal production process of the converter, the normal operation process is to supply water to the deaerator 1 from the soft water tank, introduce steam from the steam pipe network into the deaerator 1 to heat the soft water in the deaerator 1, and control it through the pressure transmitter 2 The steam pressure in the deaerator 1 makes the water temperature reach 131°C. When the converter blowing consumes the water in the steam drum, the deaerator 1 replenishes the water to the steam drum. The release valve on the deaerator 1 is generally set as an electric release valve 6. When the steam introduced by the steam pipe network through the regulating valve 7 causes the pressure in the deaerator 1 to be too high (usually 0.4MPa to open and 0.3MPa to close), The electric relief valve 6 on the deaerator 1 is opened by the PLC controller 3 . Since the action of the electric relief valve 6 is slow, when the electric relief valve 6 is opened initially, the pressure drop of the deaerator 1 is not obvious. The pressure of the oxygen tank 1 drops too fast, the water temperature in the oxygen tank 1 drops, the oxygen removal effect is not good, and the oxygen removal efficiency is affected. Since the set value range of opening and closing of the electric relief valve 6 of the deaerator is too small, the electric relief valve 6 moves frequently, and the valve is easily damaged, causing a great burden on production and maintenance.

Contents of the invention

The technical problem to be solved by the present invention is to provide a pressure release control method and system for the vaporization cooling deaerator for the above-mentioned problems existing in the existing deaerator.

The technical scheme that the present invention adopts for solving the problems of the technologies described above is:

The pressure release control method of the vaporization cooling deaerator uses two pneumatic cut-off valves to control the pressure release of the deaerator in stages:

a) When the pressure of the deaerator is higher than the first release value H1, only one pneumatic shut-off valve is opened to release the pressure of the deaerator;

b) When the pressure of the deaerator continues to rise, exceeding the first release value H1 and reaching the second release value H2, open two pneumatic shut-off valves at the same time, and keep the two pneumatic shut-off valves to release the pressure of the deaerator at the same time;

c) When the pressure of the deaerator is lower than the first dangerous value L1, immediately close any pneumatic shut-off valve;

d) When the pressure continues to drop to the second dangerous value L2, close the two pneumatic shut-off valves at the same time;

The first emission value H1, the second emission value H2, the first risk value L1, and the second risk value L2 satisfy the relationship H2>H1>L1>L2.

In the above scheme, the control method further adopts two pneumatic cut-off valves with a nominal diameter of one large and one small to control the deaerator pressure release in stages:

a) When the pressure of the deaerator is higher than the first release value H1, only the pneumatic shut-off valve with a small nominal diameter is opened to release the pressure of the deaerator;

b) When the pressure of the deaerator continues to rise, exceeding the first release value H1 and reaching the second release value H2, open the pneumatic shut-off valve with a large nominal diameter at the same time, and keep the two pneumatic shut-off valves to release the pressure of the deaerator at the same time;

c) When the pressure of the deaerator is lower than the first dangerous value L1, immediately close the pneumatic shut-off valve with a large nominal diameter;

d) When the pressure continues to drop to the second dangerous value L2, simultaneously close the pneumatic shut-off valve with small nominal diameter;

The first emission value H1, the second emission value H2, the first risk value L1, and the second risk value L2 satisfy the relationship H2>H1>L1>L2.

The present invention also provides a vaporization cooling deaerator pressure release control system, including a deaerator, a pressure transmitter, a PLC controller and a release valve are arranged on the deaerator, and the pressure transmitter and the release valve are respectively Connect with the PLC controller, the pressure transmitter is used to measure the pressure of the deaerator, the relief valve on the deaerator adopts two pneumatic cut-off valves, and the PLC controller is used to control the pressure measured by the pressure transmitter Pneumatic shut-off valve switch.

In the above scheme, the nominal diameters of the two pneumatic shut-off valves are one large and one small.

In the above solution, a safety release valve is also provided on the deaerator.

Compared with the original electric relief valve pressure control system, the present invention has the following beneficial effects:

The electric relief valve on the original deaerator is changed to two pneumatic shut-off valves with a nominal diameter of one large and one small. Compared with the electric relief valve, the biggest feature of the pneumatic shut-off valve is that the opening and closing speed of the valve is much faster. After the valve is opened, the pressure drop delay is small; using the characteristics of the pneumatic shut-off valve to open and close the valve quickly, the pressure of the deaerator is controlled in stages, which solves the problem of too fast pressure drop after the vaporization cooling deaerator is released, and the pressure control is unstable. The problem is to maintain the pressure of the deaerator at a pressure level that can send out steam for a long time, the pressure control is precise, the deaeration effect is enhanced, and the steam recovery time and the life of the vaporization flue are increased.

Description of drawings

Fig. 1 is a structural schematic diagram of the existing vaporization cooling deaerator pressure release control system.

Fig. 2 is a structural schematic diagram of the pressure release control system of the vaporization cooling deaerator of the present invention.

In the figure, 1-deaerator, 2-pressure transmitter, 3-PLC controller, 4-pneumatic shut-off valve, 41-DN100 pneumatic shut-off valve, 42-DN50 pneumatic shut-off valve, 5-safety relief valve, 6- Electric relief valve, 7-regulating valve.

Detailed ways

The technical solution of the present invention will be further described in detail below in conjunction with the embodiments and the accompanying drawings.

With reference to shown in Fig. 2, vaporization cooling deaerator pressure release control system of the present invention comprises deaerator 1, is provided with pressure transmitter 2, PLC controller 3 and release valve on deaerator 1, described The pressure transmitter 2 and the release valve 6 are respectively connected with the PLC controller 3, the pressure transmitter 2 is used to measure the pressure of the deaerator 1, and the release valve on the deaerator 1 adopts two pneumatic shut-off valves 4, The PLC controller 3 is used to control the switch of the two pneumatic shut-off valves 4 through the pressure measured by the pressure transmitter 2 .

The nominal diameters of the two pneumatic shut-off valves 4 are one large and one small.

The deaerator 1 is also provided with a safety release valve 5 .

The pressure of the deaerator 1 of the present invention is introduced from the steam pipe network through the regulating valve 7 on the side of the pressure transmitter 2, and two pneumatic shut-off valves 4 with one large and one small in nominal diameter are used——DN100 pneumatic shut-off valve 41 and DN50 pneumatic shut-off valve The valve 42 controls the release of the pressure of the deaerator 1 in stages, specifically including the following steps:

a) When the pressure of deaerator 1 is higher than the first release value of 0.4MPa, only open the DN50 pneumatic shut-off valve 42 with a small nominal diameter to release the pressure of deaerator 1, and maintain the pressure in deaerator 1 as much as possible to ensure the deaerator 1 Deoxygenation effect;

b) When the pressure of the deaerator 1 continues to rise and exceeds the first release value of 0.4MPa and reaches the second release value of 0.45MPa, open the DN100 pneumatic shut-off valve 41 with a large nominal diameter at the same time to keep the two pneumatic shut-off valves 4 releasing at the same time deaerator pressure;

c) When the pressure of the deaerator 1 is lower than the first dangerous value of 0.35MPa, immediately close the DN100 pneumatic shut-off valve 41 with a large nominal diameter;

d) When the pressure of the deaerator 1 continues to drop to the second dangerous value of 0.25 MPa, simultaneously close the DN50 pneumatic shut-off valve 42 with a small nominal diameter.

In the present invention, the DN150 electric release valve 6 on the original deaerator in Fig. 1 is changed to two DN100 pneumatic shut-off valves 41 and DN50 pneumatic shut-off valves 42 with a nominal diameter of one large and one small, and the pneumatic shut-off valve 4 is opposite to the electric discharge valve 6 The biggest feature is that the corresponding speed of opening and closing the valve is much faster, and the pressure drop delay after opening the valve is small; using the characteristics of fast opening and closing of the pneumatic shut-off valve 4, the pressure of the deaerator 1 is released by hierarchical control, which is very fast. It can solve the problem of too fast pressure drop and unstable pressure control after the vaporization cooling deaerator is released, enhance the deoxygenation effect, and increase the steam recovery time and the life of the vaporization flue.

What is described above is only the preferred embodiment of the present invention, certainly can not limit the scope of rights of the present invention with this, therefore adopts the same or similar method with this example, or the equivalent change done according to the patent scope of the present invention, Still belong to protection scope of the present invention.

Claims (3)

1. Vaporizing cooling oxygen-eliminating device pressure diffuses control method, it is characterized in that: adopt small one and large one pneumatic cut-off valve step control of two nominal diameters to diffuse oxygen-eliminating device pressure:

A) only open the little pneumatic cut-off valve of nominal diameter when oxygen-eliminating device pressure diffuses value H1 higher than first and diffuse oxygen-eliminating device pressure;

B) when oxygen-eliminating device pressure continue rise, diffuse more than first value H1 too much arrive second diffuse value H2 after, open the pneumatic cut-off valve that nominal diameter is large simultaneously, keep two pneumatic cut-off valves to diffuse oxygen-eliminating device pressure simultaneously;

C) after oxygen-eliminating device pressure is lower than the first dangerous values L1, the large pneumatic cut-off valve of nominal diameter is closed at once;

D) after pressure continues to be reduced to the second dangerous values L2, close the little pneumatic cut-off valve of nominal diameter simultaneously;

Above-mentioned first diffuses that value H1, second diffuses value H2, the first dangerous values L1, the second dangerous values L2 meets relational expression H2>H1>L1>L2.

2. Vaporizing cooling oxygen-eliminating device pressure diffuses control system, comprise oxygen-eliminating device, oxygen-eliminating device is provided with pressure unit, PLC and diffusion valve, described pressure unit, diffusion valve are connected with PLC respectively, pressure unit is for measuring the pressure of oxygen-eliminating device, it is characterized in that: the diffusion valve on described oxygen-eliminating device takes small one and large one pneumatic cut-off valve of two nominal diameters, PLC is used for the switch of Stress control two pneumatic cut-off valves recorded by pressure unit.

3. Vaporizing cooling oxygen-eliminating device pressure as claimed in claim 2 diffuses control system, it is characterized in that: described oxygen-eliminating device is also provided with Safety relief valve.