Metal Demister Pad

A metal wire mesh demister is a gas-cleaning pad woven from fine metal filament, the stainless-steel or alloy member of the demister family. It spans the gas outlet of a separation column or upright vessel, so every bit of gas leaving is driven through it. As the gas snakes between the wires, its droplets are removed by three mechanisms acting at the same time. Momentum carries the bigger droplets straight into the wire when the gas turns aside, and that is impaction. Finer droplets that do follow the gas still brush the wire in passing and are caught, which is interception. And whatever lands joins the film already on the wire, building larger and larger beads, which is coalescence. When a bead is too heavy to hold, it drops from the base of the pad and returns to the liquid below. The weave is mostly empty volume, so the gas gives up very little pressure to cross it, while the sheer footage of wire packed inside makes the capture thorough.

The wire is chosen for the gas it must live in. Carbon steel, grade Q235, is the cheapest and is fine for dry, non-corrosive gas. Standard 304 or 304L stainless is the usual choice and resists ordinary corrosion and oxidising acids well. Where chlorides or harsher acids are present, 316L stainless holds up much better. For genuinely hot gas, 321 is a stabilised stainless that keeps its strength at high temperature. When the chemistry turns severe, exotic metals earn their cost: nickel and Monel for hot caustic and alkalis, titanium for chlorides, wet chlorine and seawater-like duty. As a rule of thumb: Q235 for clean gas, 304 for general service, 316L for chlorides and acids, 321 for heat, and nickel or titanium for the extreme cases. Tell us the gas, its temperature and what is in it, and we will name the alloy.

Both trap mist in the same manner; the deciding factor is the wire. A metal pad, stainless or an alloy, is rigid, survives a deep bed or a pressure spike without deforming, and above all endures heat, staying serviceable at several hundred degrees where plastic would sag. Through alloys such as titanium and nickel it can also reach a corrosion resistance no polymer offers. A plastic pad, by contrast, is light, inexpensive and superb against certain cold, aggressive acids, but it loses strength as it warms and rules itself out of hot or load-bearing duty. The dividing line is therefore straightforward: pick metal for heat, for mechanical strength and for alloy-grade corrosion resistance, and pick plastic for cool, fiercely acidic gas where cost and chemical resistance matter most. Describe the temperature and what the gas contains, and we will point you to metal or plastic.

A metal wire mesh demister earns its place wherever a hot, pressurised or mechanically hard duty demands the mist be taken out of a gas. You will find it capping distillation towers, absorbers and reactors, sitting in knock-out drums and separators, and mounted on storage tanks and process vessels throughout the chemical, petrochemical, pharmaceutical, light-industry and environmental fields. Clearing the droplets pays back three ways at once: the column separates more sharply, product stops leaving with the vapour, and the compressors, blowers and lines beyond are shielded from corrosion and fouling. Each pad is knitted circular and trimmed to its vessel, commonly for bores of roughly DN300 to DN5200, larger by arrangement, and carries ISO 9001 certification. Describe the vessel and the stream, and we will specify the pad and the grade of metal.