報告書番号

U92024

タイトル（和文）

冷却水炉系におけるムラサキイガイ等の付着生物防除対策－温風処理の実用化の検討－

タイトル（英文）

CONTROL OF MUSSEL FOULING WITH HOT AIR -PRELIMINARY STUDY FOR PRACTICAL APPLICATION-

概要 （図表や脚注は「報告書全文」に掲載しております）

発電所冷却水路系の付着生物防除対策である温風処理法に必要な熱量について，熱量計算を行った。付着生物の温度を常温から５０度に加温する熱容量は約４０００ｋｃａｌ，処理初期に必要な熱量は２２００ｋｃａｌ／ｈ，定常状態での熱放散量は４３８ｋｃａｌ／ｈと試算された。温風処理は，環境に悪影響を及ぼさない無公害型の対策である。ただ，海水を抜いた状態で処理を行うので，処理のために一時的に通水を休止できる火力ユニットに適用が限定される。近年一般化しつつある撥水性の塗料と比較するとコストは温風処理のほうがやや高いが，温風処理は無人化できる利点がある。また，塗装が困難な小口径の配管や復水器管板なども処理することができる。

概要 （英文）

THIS REPORT PRESENTS THE RESULTS OF CALCULATIONS ON THE AMOUNT OF HEAR REQUIRED FOR HOT-AIR ANTIFOULING TREATMENT IN A SEAWATER CONDUIT OF A POWER STATION,AND MAKES COMPARISON WITH OTHERANTIFOULING METHODS. CALCULATION : 2-M CONDUIT REQUIRES ABOUT 4,000 KCAL/H PER METER TO HEAT FOULING ORGANISMS AND THE CONDUIT FROM 15 TO 50 DEGREE. IN THE EARLY OPERATION PERIOD,ABOUT 2,200 KCAL/H PER METER ISNEEDED. THIS IS EQUIVALENT TO 130KW FOR TREATING A 50-M LONG CONDUIT. IN THE EQUILIBRIUM STATE,ABOUT 438 KCAL/H PER METER IS REQUIRED FOR UNDERGROUND CONDUIT TO MATCH RADIATED HEAT FROM THE CONDUIT. EXPERIMENT :WHEN HOT AIR AT 94 DEGREE WAS BLOWN INTO A 1.8-M SEAWATER DISCHARGE UNDERGROUND CONDUIT,THE HOT AIR MIXED RAPIDLY WITH THE AIR IN THE CONDUIT. THE AIR TEMPERATURE AT THE CENTER OF THE CONDUIT 10 M FROM THE HOT-AIR BLOWING POINT REACHED 50 DEGREE. THREE HOURS LATER,THE TEMPERATURE OFTHE SIDE WALL NEAR THE BLOWING POINT REACHED 40 DEGREE. TAR-EPOXY COATING,WHICH IS COMMONLY USED IN SEAWATER CONDUITS,WAS NOT DAMAGED BY THE HOT-AIR TREATMENT IN THE TEST CONDUIT. COMPARISON WITH OTHER ANTIFOULING METHODS : HOT-AIR TREATMENT IS A POLLUTION-FREE ANTIFOULING METHOD. HOWEVER,IT IS USEFUL ONLY FOR POWER PLANTS THAT CAN STOP OPERATION TEMPORARILY. THE HIGH-WATER-VELOCITY METHOD,ANOTHER POLLUTION-FREE ANTIFOULING METHODS,REQUIRES A HIGH WATER VELOCITY DURING THE SETTLING SEASONS FOR FOULING ORGANISMS. THE HOT-AIR TREATMENT NEEDS ONLY TWO OR THREE TREATMENTS PER YEAR TO REDUCE FOULING ORGANISMS. HOT-AIR TREATMENT CAN ALSO BE DONE BY UNMANNED OPERATION,BUT THE COST IS A LITTLE HIGHER THAN REPELLENT ANTIFOULING PAINTS WHICH ARE BECOMING POPULAR. HOWEVER,HOT-AIRTREATMENT CAN BE DONE EVEN IN SMALL PIPES AND TUBES WHERE ANTIFOULING PAINTING IS DIFFICULT.

報告者

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