The closed soft water cooling loop of blast furnace detection method
The present invention is the detection that blast furnace water-cooling furnace wall employing closed soft water cooling loop leaks, and belongs to the technical field of smelting of iron and steel.
Since the seventies, the blast furnace water-cooling refrigeratory adopts closed soft water or pure water cooling loop more prevalently both at home and abroad.China has adopted the large and medium-sized blast furnace (350-3200M that goes into operation or be about to go into operation of closed soft water cooling loop since national big-and-middle-sized blast-furnace shaft life-span discussion in 1984
3) above 10, blast furnace adopts the necessity of closed soft water cooling loop to become the common recognition of domestic ironmaking circle, compare with the service water cooling loop that we opens, the cooling of closed soft water cooling loop is fully reliable, the running energy consumption is hanged down and water resource is lost advantages such as minimizing significantly, remains in certain difficulty and inconvenience but leak in the refrigeratory breakage that detects this loop at present.
The existing detection method that detects the closed soft water cooling loop of blast furnace leakage is:
The Leak Detection of 1 whole loop:
Closed soft water cooling loop of blast furnace and atmospheric isolation, so no vaporization loss, under the tight situation of pipe joint and valve seal, unique normal leakage of whole loop only is sealing place of water circulating pump, under certain hydraulic pressure, it is constant that its leakage rate keeps over a period to come basically.The underheat degree of volumetric expansion when raising for soft water temperature in the compensation loop and raising soft water seals the expansion drum that is typically provided with filling certain pressure nitrogen in the soft water cooling loop.Be located at water level gauge on the expansion drum and both can be used for controlling the keying of supply soft water valve, can monitor the leakage situation of whole loop again according to the variation process of water level, the interior water level of normal condition expansion drum reduces over time, and rule is more stable, occur new leakage in the loop, SEA LEVEL VARIATION is obviously accelerated.This method can only determine that big damaged the leakage appearred in the stove intercooler, damages but can't predict that refrigeratory.
2 refrigeratory branch Leak Detection:
Determine the position of damaged refrigeratory, at first will find out that branch and have leakage, existing following several method:
(1) install high precision flow (as electromagnetic flowmeter) on the water supply of each branch and return pipe, can be at any time monitor according to the difference in flow of water supply backwater whether each branch occurs leaking, but the branches of full stove is numerous, construction investment and maintenance cost are huge.
(2) water supply and the backwater valve before and after the suspicious branch of shutoff, this branch and whole loop are cut off, if the refrigeratory that this branch connected has leakage, because gas pressure is higher than the hydraulic pressure in this branch behind the partition in the stove, coal gas will enter in the branch by breakage, water in the branch also will enter in the stove simultaneously, and such air inlet result of leaking can make pressure in the branch present to a certain degree rising.Therefore,, actual be difficult to judge that cutting off back branch internal pressure raises, and show and have or not leakage as no rich experience.
(3) adopt coal gas detector or electricity to lead leak detector and survey leakage.This type of detector is normally placed on the coal gas drip catcher of top return pipe, is generally used for the Leak Detection of blast furnace periphery Shang Ge district refrigeratory, if be used to detect then One's name is legion of each branch, and investment and maintenance cost is increased severely.The pipeline that this method detected still is communicated with whole loop, therefore, if comprise that the hydraulic pressure of the breakage that fills nitrogen pressure in the expansion drum is higher than gas pressure in the stove, just can only leak in stove by breakage, and coal gas can not enter in the refrigeratory in the stove.Even hydraulic pressure is lower than gas pressure in the stove in addition, catch that productive set also needs the time of growing to certain coal gas amount of instrument sensitivity in the gas device on the return pipe but will make.
(4) connect the two ends of suspicious branch with transparent tube, and this branch and whole loop are cut off, when coal gas entered in the branch by breakage, the water in the branch also bled in the stove, decline of water table in the transparent tube is until the surface level place that is stabilized in the refrigeratory breakage.Though the comparison of this kind method is directly perceived accurately, branch's time of cutting off the water supply is longer, might enlarge existing breakage or cause new damage.
The detection of damaged refrigeratory position in 3 branches:
The method of damaged refrigeratory position is with small-sized coal gas drip catcher in the detection branches at present both at home and abroad more commonly used and easy, and whether the gas that the gas device enters is caught in igniting examination combustion detonation sound, and detecting refrigeratory has not breakage.But this method is in when igniting during by damaged refrigeratory discharging coal gas and steam is often arranged, so ignition difficulties.In addition when hydraulic pressure branch in was higher than in the stove gas pressure, coal gas just can not enter and catch in the gas device, and having only could be with catching the detection of gas device when branch and whole loop partition.
The object of the invention is to leak at existing closed soft water cooling loop of blast furnace the detection method of branch, exists and can not onlinely detect, and it is more to be equipped with instrument system, and detection time is long, and sensitivity is not high, shortcomings such as poor reliability.The present invention adopts the detection method of the leak detection loop and the airtight no potential head soft water leak detection loop of closed soft water cooling loop.Closed soft water cooling loop of blast furnace is carried out online leak detection, and its leak detection speed is fast, highly sensitive.
Content of the present invention is the detection method of the leak detection loop and the airtight no potential head soft water leak detection loop of closed soft water cooling loop of blast furnace, comprise unlimited soft water leak detection loop and high pressure leak detection loop, can detect the open damaged leakage branch of blast furnace water-cooling loop respectively and detect the leakage branch that microcrack is only arranged.Utilize water level gauge, high sensitivity flowmeter and high sensitivity CO detection paper instrument detect, and determine the open branch of leaking, and microcrack leaks branch, and can detect the cracking position.Can to be single leak detection loop hunt leak also available fixing or portable touring leak detection system to a plurality of cooling loop branch to this leak detection loop.
The thick black line of Fig. 1 is partly represented the leak detection loop of closed soft water cooling loop of blast furnace, and the thick black line of Fig. 2, Fig. 3 is partly represented airtight no potential head soft water leak detection loop.The thin thread part of Fig. 1, Fig. 2, Fig. 3 divides the expression closed soft water cooling loop of blast furnace loop of promptly working.Leak detection loop and airtight no potential head soft water leak detection loop mainly comprise: leak detection looped cycle water pump (14), against current valve (15), the high precision flow (16) of leak detection comprises that electromagnetic flowmeter or vortex shedding flow meter place the pipe system of water supply and backwater respectively, leak detection water supply collector (17) and backwater collector (20), the demineralized water tank (13) that opens wide, supply soft water pipeline (12) from the blast furnace cooling loop, the leak detection backwater refrigeratory of blast furnace cooling loop secondary cooling water pipeline (22), the small-sized refrigeratory of leak detection system (21), leak detection water pipe and valve (23) from the blast furnace cooling loop, return the leak detection water pipe and the valve (24) of blast furnace cooling loop, the flexible pipe and the joint (18) that connect blast furnace cooling loop branch, small-sized coal gas drip catcher (19), open wide the backwater valve (25) of soft water leak detection loop, vent valve (26).
Closed soft water cooling loop of blast furnace sees that Fig. 1, Fig. 2, Fig. 3 thin thread part branch comprise: the threeway (9) of soft water station supply channel (7), demineralized water tank (6), additional soft wa ter pump (5), water circulating pump (4), expansion drum (3), the cooling arm (10) that replenishes nitrogen inlet (2), air primary cooler (1), supply channel (8), water return pipeline (11), refrigeratory, connection blast furnace cooling circuit and leakage detecting circuit.
The present invention leak detection is three grades of leak detection systems, and first order leak detection is provided with pressurising nitrogen expansion jar and water level gauge for closed soft water cooling loop of blast furnace, and record decline of water table speed when this fall off rate has when increasing significantly, illustrates that there is bigger leakage in this system.Second level leak detection is the leak detection loop of closed soft water cooling loop of blast furnace, utilizes two high precision flows of supply channel and water return pipeline; Electromagnetic flowmeter or vortex shedding flow meter, the discharge of turnover pipeline that detects a refrigeratory or one cooling arm is poor, and its sensitivity determination is equivalent to water cooler and the leakage rate that Φ 1-2mm boring causes occurs, and adopts Fig. 1-3 leak detection loop detection.When third level leak detection determines that hydrocooler and water-cooled branch leak, for further determining the leak position.Utilize the refrigeratory breakage to cause the interior gas leak of stove to collect, and utilize highly sensitive CO detection paper instrument to detect, can determine the leak position by a survey for gas collector.Utilize CO test paper replaced C O point methods, solved the problem that is difficult for lighting because of coal gas band water, thereby improved leak detection efficient.
The detection step of leak hunting method of the present invention at first, is the leak detection of cooling system cyclic system, secondly for the leak detection that circulates successively of each take-off pipe of cooling system, determines to leak branch, at last by to leaking coal gas leak detection that branch leaks so that definite leakage position.
(1) detection of cooling loop systematic water level, mainly comprises the expansion drum (3) of figure (1) filling nitrogen, set up water level gauge and SEA LEVEL VARIATION registering instrument on it.During detection, Open valve (23), (24), valve-off (25), utilize water level gauge and registering instrument detection loop systematic water level to change, quicken, show that then leaking appears in cyclic system when SEA LEVEL VARIATION.
(2) detection of cooling loop branch road high precision flow, when the cyclic system leakage occurring, in order further to carry out branch road cycle detection successively by each bye-pass of cooling system, this detection system comprises soft water water circulating pump (14), the water supply of branch line and the high precision flow of backwater (16), during detection, valve-off (23) (24), Open valve (25), start the soft water water circulating pump of leak detection loop, supply water, connect the branch road of each loop successively to the pipeline branch road, detect the water supply of the branch road that utilizes detection and the high precision flow of backwater and measure its difference in flow, to determine the leakage of branch road.
(3) cooling loop branch road coal gas drip catcher detection branch is leaked, finish on the above-mentioned secondary detection basis, the detection of the definite branch road leakage position that carries out, this system comprises coal gas drip catcher (19), high sensitivity CO detection paper instrument, during detection, on the cooling loop arm that fixed discovery is leaked, insert the coal gas drip catcher at check point respectively and collect the coal gas that leaks, utilize high sensitivity CO detection paper instrument to detect the coal gas that captures, the position of CO test paper color development is confirmed as leakage position.
After invention utilizes high precision flow to detect a loop branch, utilize two standby flexible pipes to connect another branch line to be detected and leak detection loop, leak detection loop and water circulating pump supply water to two branch lines that are connected simultaneously, the three-way valve at the branch line two ends detected are transformed into to connect blast furnace close.After closing the cooling loop system, begin to detect the branch line that knot detects again.
The method that 1 open type soft water leak detection loop detection refrigeratory branch leaks.
(1) at the branch two ends of intending detecting, use flexible pipe to be connected T-valve (9) and leak detection water supply collector (17) and leak detection water return pipeline (20) with joint (18) respectively, permanent leak detection all is set with under the situation of connecting tube in each branch, then can omits the work of mounting or dismounting flexible pipe.If adopt the then available PLC of the T-valve system control of straighforward operation at the two ends of each branch, reach and regularly detect each branch successively or selectively automatically.
(2) under the situation that valve (23), (24) shutoff and valve (25) are opened, the T-valve of intending the detection branches two ends is transformed into and opens wide the position that the leak detection loop is connected.At this moment because water circulating pump (14) exit of leak detection loop is provided with reverse checkvalve (15), the unlikely emptying of the water in this branch.
(3) start leak detection loop and ebullator (14) and supply water to this branch, whether water supply and the circling water flow rate of observing this branch with high precision flow (16) have difference, if difference in flow is arranged, show that promptly there is leakage in this branch, otherwise do not have leakage.
(4) when judging that with the leak detection loop there is leakage in this branch, just have and do not accumulate coal gas with coal gas drip catcher (19) inspection, detect the damaged particular location that leaks refrigeratory by high sensitivity CO detection paper instrument.Should be noted that hydraulic pressure should be lower than gas pressure in the branch.Can suitably turn down water supply collector (17) and go up the valve that supplies water to this branch, to reduce the interior hydraulic pressure of branch.
(5) if that branch that judgement is crossed with the leak detection loop detection does not have is sewed, just another branch that intends detecting is connected with the leak detection loop with two other flexible pipe, the water circulating pump of the loop of hunting leak just supplies water to two branches simultaneously.Subsequently the preceding T-valve that has detected those branch two ends that finish is transformed into the position that is connected with the airtight cooling loop of blast furnace.So just begun the detection of second branch.
The 2 high pressure loop detection of leaking hunting has the leakage branching method of microcrack:
(1) valve-off (25), Open valve (23), (24), high pressure soft water from the airtight cooling loop of blast furnace just enters leak detection water supply collector pipe (17) by the flowmeter (16) of below, after flowing through the refrigeratory branch that intends detecting, enter leak detection backwater collector (20) and turn back to water cooling system by the flowmeter (16) of top again, also be according to the difference in flow of water supply, judge whether this branch has leakage with backwater.
(2) judge a certain branch exist leak after, connect the two ends of this branch with transparent tube, and this branch and blast furnace cooling loop partition.
(3) keep opening for the microcrack that makes damaged refrigeratory, need in this branch, to add again the portable small-sized nitrogen cascade (not marking among Fig. 1) that fills of a special use, (gas pressure in the only suitable a little higher than stove of hydraulic pressure branch in is in order to avoid the water interior even emptying of stove of bleeding in a large number in expanded crack and the branch with the hydraulic pressure in this branch after improve cutting off.)
(4) judge damaged position by the stationary value of water level reduction in the transparent tube.
The detection method of 3 airtight no potential head soft water leak detection loops:
For potential head and the resistance to flow that overcomes in the cooling water pipe changes the demineralized water tank (13) that opens wide into be full of soft water or little air is only arranged on the groove top closed demineralized water tank such as Fig. 2 on the basis of Fig. 1, pressure in the cooling water pipe of somewhere on the blast furnace height like this, only overcome remaining static pressure after the resistance to flow that arrives this place for the pump (14) not of circulating, pressure in the cooling water pipe is easier to be lower than gas pressure in the stove, enters cooling water pipe thereby be convenient to the interior coal gas of stove.On the device structure except that demineralized water tank (13) is made into the closed, establish a vent valve (26) at this groove top.Sequence of operation when detecting need make the following changes:
(1) under the situation that vent valve (26) is opened, behind the startup water circulating pump (14), the blast furnace cooling loop followed (12) to demineralized water tank (13) moisturizing, and the air on groove top is discharged by vent valve.
When (2) treating that water that vent valve (26) is discharged is not with bubble, turn-off the valve of supply hose (12) earlier, close vent valve (26) again, this moment, the Leak Detection loop just was in airtight no potential head running status.
If intend taking demineralized water tank (13) top to remain the method for operation of part air, then airtight demineralized water tank (13) is arranged on the highest point of Leak Detection loop, as shown in Figure 3.
The present invention is provided with special-purpose leak detection cyclic system, comprises leak detection looped cycle water pump, against current valve, high precision flow, be arranged on the water supply and the water return pipeline of leak detection loop, leak detection water supply collector and backwater collector open wide or airtight demineralized water tank and vent valve, from blast furnace loop supply soft water pipeline.Connect blast furnace cooling loop leak detection water supply and return water lines, blast furnace cooling loop branch and leak detection loop connecting line cool off branch with the leak detection of high sensitivity CO detection paper instrument and leak.The soft water leak detection loop leak hunting method that opens wide, valve-off (23), (24), startup valve (25) start leak detection looped cycle water pump (14) again, utilize high sensitivity CO detection paper instrument to detect at coal gas collector place.
High pressure of the present invention leak detection loop leak hunting method, valve-off (25), Open valve (23), (24) are introduced leak detection loop traffic meter (16) from the soft water of the airtight cooling loop of blast furnace and are measured and supply water and return the water route difference in flow and hunt leak.
The airtight no potential head soft water leak detection loop of the present invention changes the demineralized water tank that opens wide into closed demineralized water tank (13), the top of groove is provided with vent valve (26), open vent valve during leak detection, start leak detection looped cycle water pump (14), by pipeline (12) to the demineralized water tank moisturizing, treat that water is full of demineralized water tank and closes vent valve again, make leakage detecting circuit be in airtight no potential head soft water leak detection loop running status.Its leak hunting method is identical with the method for open type demineralized water tank leak detection loop.
Technical characterstic of the present invention: the auxiliary coolant system of providing low pressure weep amount for oneself constitutes the leak detection loop, at leak detection cooling arm or refrigeratory, the refrigeratory of being hunted leak is not cut off the water supply, and belongs to the cyclic system of online leak detection, does not influence the life-span and the ordinary production of the water-cooling wall of blast furnace.And when guaranteeing to occur refrigeratory damaged, CO coal gas is easy to discharge from leak, is convenient to determine the leak position with the leak detection of CO detection paper instrument.The present invention uses the CO test paper highly sensitive, and has chromogenic reaction speed to be easy to leak detection soon.The breakage of Φ 2mm appears in water cooler, CO+H in the gas leakage
2Content surpasses 20%, and about 30-40 will develop the color second.The present invention only needs a small amount of high-precision flow to take into account a water circulating pump and pipeline and valve, and is simple in structure, small investment, and flexible operation, leak detection is sensitive.
Leak detection system that this is complete and method have comprised three grades of leak detections promptly:
Water level gauge on the 1 usefulness cooling loop illustrates decline of water table speed, judges whether total system has leakage;
2 usefulness arms high precision flow up and down judges whether a certain arm has leakage;
Coal gas drip catcher on the 3 usefulness arms captures coal gas and judges have CO to leak outside from refrigeratory with high sensitivity CO test paper, thereby judges the leakage of some refrigeratorys.
The present invention can be fixing leak detection loop and patrolling leak detection loop (vehicular), and therefore, the instrumentation environment is good, is easy to safeguard long service life.