Flame Arresters: Chemical, Agrochemical & Pharmaceutical Applications

Elmac Technologies flame and explosion prevention systems are used to provide safety and environmental protection across the international chemical and pharmaceutical industries. Flame arresters guard piping, ducts and storage tanks against the accidental ignition of flammable vapours.

Most flame arresters comprise an element and housing suitable for installation into pipework or process plant. The element is a permeable matrix that quenches the flame, but allows gas to flow. In the event that a flame front reaches the element, the flame is extinguished and the accompanying pressure wave or shock wave is attenuated.

Applications include:

Vents for storage tanks & waste vapour vents

• Both in-line and end-of-line flame arresters are fitted on the vent nozzles of storage tanks. In-line arresters are used where the gas or vapour needs to be vented at a safe distance from the tank or vent
• In some cases, where the line vents at a distance from the tank, detonation arresters are used. This is typically when the distance to the ignition source is more than the prescribed limit for deflagration arresters. Typical solvent vapours include methanol and kerosene (IIA gases) and butadiene (IIB2 gases)

Gas scrubber vents

• Both in-line and end-of-line flame arresters are used on vent lines from gas scrubber units. An end-of-line unit would be placed on a vent where the vapour passes directly to atmosphere should the scrubber fail to catch the flammable vapour
• In-line flame arresters are used after the scrubbing or cleaning of a reactant or carrier gas such as ethylene (IIB3 gas) or propane (IIA gas)

Loading facilities

• In-line flame arresters are fitted on vapour return lines for many bulk storage chemicals including dibutyl ether (IIB2 gas) and cyclohexanol (IIA gas) and dipropyl ether (IIB3 gas)

Pumps & rotating machinery

• Any machinery handling flammable material which could, in an upset condition, generate excessive heat or sparks is fitted with an in-line arrester to prevent the passage of a flame to other parts of the process

Reactor vents & vapour lines

• Both in-line and end-of-line flame arresters are fitted on the outlets of reactors. End-of-line arresters are used where the vapour is ejected directly to the atmosphere and in-line units are used where solvent vapour or reaction products are transferred to the next stage of the process
• Typical vapours include acetone and ethanol (IIB1 gases) and tetrahydrofuran (IIB1 gas) and dimethyl ether (IIB2 gas). Careful consideration must be given to the position of the arrester in relation to the source of ignition

Knock-out pots

• End-of-line flame arresters are used on the vent lines from knock-out pots (catch-pots) which are designed to catch reactor contents should an uncontrolled exotherm or overdriven reaction occur
• Any flammable vapours in the reaction mixture will vent out of the knock-out pot, and the flame arrester will stop transmission of any flame caused by external of environmental sources