How to troubleshoot the increased resistance of solvent recovery system and the increased load of fan? Answer: Resistance is the first signal of blockage, and there are three categories of resistance: differential pressure climbing of adsorption bed, liquid accumulation at the low point of pipeline, and blockage of filter and valve. The judgment method is to compare the pressure difference trend: the resistance of the new system is low and stable, and the slow climbing with the running time is normal dust accumulation, and the step jump must have blocking points. The synchronous upward movement of fan current and resistance is two manifestations of the same thing. Don't just check the fan but not the pipe network. This article clarion the class-by-class investigation and disposal methods.
The on-site performance of increased resistance is very intuitive: the fan current is higher than that in the initial stage of operation, the opening degree of air volume adjustment is larger and larger, the reading of bed pressure difference gauge continues to rise, and the air volume at the remote collection point is smaller. These signals are inconspicuous on their own, and when combined, the system is narrowing. The ledger value is highlighted here: the resistance baseline at the time of commissioning and the resistance retest value after each overhaul are the basis for judging the climb rate. If there is no baseline, the site will be rebuilt according to the current data after maintenance, and the subsequent comparison will be made on a monthly basis. If the rate of climb suddenly accelerates, it can basically be concluded that there is a new blocking point, rather than normal dust accumulation.
Adsorption bed is the big head of resistance change: the bed layer is gradually blocked by dust and liquid in the air inlet, which shows that the pressure difference climbs smoothly; The bed layer collapses or scabs to cause bias flow, the pressure difference jumps and the treatment efficiency decreases. Disposal is divided into two levels: if the pressure difference is close to the upper warning limit, the adsorbent shall be cleaned or replaced according to regulations; In case of bias flow and scarring, check whether the pretreatment of intake air fails, the front-end filtration and defogging are not repaired, and the carbon will be blocked again soon after replacement. The resistance shall be remeasured and recorded as a new baseline segment after carbon replacement. Bed maintenance is a confined space operation. Enter after passing the replacement test. Don't open the door based on experience.
The low point of the pipeline is a hidden blockage point: solvent vapor condenses in the low temperature pipe section, the accumulation occupies the diameter, and the resistance rises step by step, especially in winter. The search method is to touch the abnormal temperature section and listen to the condensate discharge valve along the process. The liquid accumulation position is often at the low point of the long-distance horizontal pipe and the blind section that has not been purged after shutdown. Disposal is condensate drainage and purging. The fundamental solution depends on design: drain valve is set at the low point, pipe diameter is checked according to condensate volume, and heat tracing covers the low temperature section. Condensing operation collects materials according to regulations. Directly discharging the ground is both illegal and dangerous. Condensate is managed according to hazardous waste or recycling channels.
The front-end filter is replaced or cleaned according to the pressure difference. Don't wait for the resistance alarm to act. The alarm value has already affected the air volume. The specifications of the filter element are selected according to the characteristics of the media particles. The filter element that is too thin is blocked quickly, while the filter element that is too thick cannot be blocked. It is balanced according to the data. Valves are checked one by one: whether the opening of the regulating valve is consistent with the feedback of the actuator, and the astringent actuator will make the valve think fully open in half a meeting; Check the scaling and jamming of the valve plate to increase local resistance, and the disassembly and inspection period shall be determined according to the cleanliness of the medium. The fan body is also checked: dust accumulation in the inlet muffler and fouling on the impeller will make the current go up, and balance check will be done after cleaning the fouling.
| Source of resistance | Form of expression | Investigation methods | disposal method |
|---|---|---|---|
| Adsorption bed blockage | Differential Pressure Steady Climb | Trend of bed pressure difference | Cleaning or charcoal replacement |
| bed drift | Differential pressure jump efficiency drop | Temperature measurement and efficiency comparison | Check pretreatment for carbon exchange |
| Pipeline effusion | Ladder rise winter heavy | Temperature inspection of condensate drain valve | Condensing, purging and heat tracing |
| Filter | Front end differential pressure high | Differential pressure gauge reading | Clean or replace the filter element |
| Control valve | Air volume adjustment failure | opening feedback comparison | Overhaul actuator |
| Fan body | Low current high efficiency | Measure current after cleaning scale | Clean scale to balance |
Looking at the rate does not look at the absolute value: by monthly comparison, climbing will be overhauled as planned within the expected period; If you suddenly accelerate or exceed the upper limit of the warning, check immediately according to the new blocking point. Delay will turn insufficient air volume into collection failure.
Check the blocking point of non-liquid phase: filter paste blocking, valve jamming and bed scarring are all possible; Pressure measurement is carried out section by section along the process flow. The sudden change of pressure difference is the blocking point. Don't just focus on one direction of condensate.
The new carbon plus clean pipe network can be close to the initial value; If the retest is still high, it means that there are still blocking points in the filter, valve or pipeline. Don't use carbon replacement as a panacea, and retest and locate the residual blocking points section by section.
This article by LuoyangWohong PetrochemicalEquipment Co., Ltd. arranges that the company provides design, manufacturing and operation and maintenance services for condensation recovery, membrane separation recovery and complete solvent recovery devices for chemical and pharmaceutical enterprises. If you need process evaluation or scheme configuration, please contact and exchange.
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