انتخاب متریال مناسب برای اسکرابر:
یکی از سخترین و مهمترین انتخابات متریال مناسب برای ساخت اسکرابر تر(مرطوب) می باشد . مسلۀ آلودگی ،خوردگی ،شستشویی تجهیزات ،فرسایش ،مشکلات دمایی، از جمله مشکلات یک مهندس برای خرید و یا ساخت اسکرابر مرطوب است،که ممکن است این مشکلات دریک زمان رخ بدهد، بنابراین انتخاب درست متریال مناسب بهترین گزینه می باشد.در ادامه به بررسی متریال مناسب برای ساخت اسکرابر می پردازیم که طراحان و سازندگان بتوانند از بهترین و ارزانترین متریالی که در اختیار دارند اقدام به ساخت اسکرابرنمایند
Metallic Scrubber Materials:
Carbon Steel is probably the material most commonly specified for scrubber construction because it is easily fabricated and versatile. However, because of its limited corrosion resistance, which depends upon an oxide film, carbon steel is not recommended for scrubbing applications where dilute acids are present. It is recommended for dust collection systems or in scrubbers operating with basic solutions
Cast Iron, where available is probably the most economical material for wet scrubbers. Units with few or no moving parts may be fabricated from it. Most cast iron scrubbers use stainless steel trim or other corrosion resistant alloys for spray nozzles and components where close dimensional tolerances must be maintainedCast Iron may also be used in pilot plant scrubbing applications or where corrosion problems are not severe. Normal water supplies and air will not cause problems. However, S02 or similar gases in the fluid being scrubbed will cause the formation of dilute acids which will attack cast iron.
Ni Resist Cast Iron Alloys containing 13.5 to 36 percent nickel are generally recommended for scrubbing applications where corrosion, erosion, high temperature or abrasion exist simultaneously. These alloys are particularly well suited to scrubbing of incinerator fumes or other fumes where high temperatures and flyash are present. Ni Resist alloys have much higher resistance to corrosion than plain cast iron or steel, but are not recommended where oxidizing agents are encountered.
Stainless Steels most commonly used in wet scrubber fabrication include types 304 and 316, either in their standard or low carbon forms. Both of these materials form an oxide film, and perform best under oxidizing conditions. They are not recommended, however, for use with hydrochloric acid or other reducing acid environments. Both have good temperature resistant properties and are often recommended for incinerator applications where relatively high temperatures are present. Extra low carbon types are recommended in both type 304 and 316 to prevent intergranular corrosion from scrubber fabrication.
Medium Alloys such as Alloy 20 are used in many scrubber applications, particularly for sulfuric acid service. Materials such as Hastelloy C can also be used, but these alloys are not recommended unless absolutely necessary.
Plastic Scrubber Materials:
Fiberglass Reinforced Plastic (FRP) is used in wet scrubber construction because the material is economical, easily fabricated, lightweight, and has good resistance to both alkaline and acid environments. The particular FRP resin used for scrubber construction, however, should be carefully selected on the basis of its resistance to the environment. In general, FRP can be used for handling most strong acids or alkalis. Where necessary, an FRP scrubber can be equipped with a Dynel shield to prevent attack of the glass fibers in fluoride scrubbing. Limitations on the use of fiberglass include temperature (which generally must be below 220 F) and the presence of certain organic compounds which will attack the resin. FRP is used both as the basic material for scrubber fabrication, or as liner material for steel equipment which is subject to corrosion.
Polyvinyl Chloride (PVC) has limited use as a material for wet scrubber construction because of its low temperature limitations (generally 140-160 F). However, this material can be used for low temperature applications involving acids, alkalis, or dust. Most often, PVC is used for components such as spray nozzles or other standardized parts, as well as for packed tower grids and redistributors.
Furan (Furfuryl Alcohol Resin) is particularly well suited to scrubber applications where the acid and alkali resistance of FRP is required, but where organic solvents such as Xylene or Trichlorobenzene are present. Strength and temperature properties are similar to FRP which cannot be used with these organic compounds.
Resins of the phenolic type are normally recommended for scrubber applications where chlorine or hydrogen chloride are encountered.