Operating introduction

(1)   General

Traditional stainless steel strip continuous annealing applies light diesel as fuel supply, and recently affected by international raw oil supply, the price of fuel oil is high and fuel costs much, thus, we introduce the hot dirty producer gas strip continuous annealing furnace, which is successfully applied to three strip annealing furnace of one stainless steel manufacturing company. Hot dirty producer gas after simple treatment of dust removal is directly used by annealing furnace with a status of high temperature, few tar and dust; the dust capacity of fuel gas is for the national environment requirement, especially the cost is 30%-40% less than the diesel’s.

(2)   Gas generating station

We will make a reasonable configuration of gas producer according to customers’ process requirements with corresponding ancillary devices; furnace inlet is provided with cyclone and disk valve, and hot gas dedusted is used for annealing furnace.

(3)   Furnace body

l  Set the amount of strip inside according to users’ product capacity, single or double floor strip. Normally it is 2-4 strips.

l  Set several furnace rolls with respect to furnace length

l  Furnace lining applies light construction to strengthen insulation of furnace body

l  Furnace roof is of fabric modular structure.

l  Furnace wall and hearth is of multi-floor structure.

l  According to process and production capacity, distribute scores of specialized burners on both sides along furnace length, which is of the functions of modulation and cut down, and can remove dust in the event of nonstop.

(4)   Drainage system and waste heat recovery system

Smoke is forced to be discharged by using upper row smoke structure and induced-draft fan. Duct is set with high-efficient pipe-type air preheater and steam recovery device. Preheat combustion air to 300-500℃ to assist annealing furnace fire, and steam and recovered steam is for other usages in plant.

(5)   Air system

Supply blast by blower. The gas general pipe is in an inner heat insulation masonry while main pipe and branch pipe apply external heat insulation wrap; take more insulating measurements, reduce the loss of air and gas sensible heat and improve waste heat recovery efficiency.

(6)   Instrument control system

l  Gas station is available to every furnace and has its own control system that is in charge of every operating parameters separately.

l  Set several area temperature detector in the front and back of inner furnace and waste heat recovery system and according to annealing process requirements, differs the amount of regulating burners.

l  Apply variable frequency adjusting control to gas furnace fans, combustion fans and induced draft fans according to users’ requirements.

(7)   Primary technical index

l  Strip steel specification is constant with users’ standards

l  Strip dealing ability normally is 5-12t/h for a single furnace

l  Furnace inner strip quantity: set in single floor or double floor according to customers’ requirements, and treat 2-4 strips at same time

l  Fuel: hot dirty producer gas

l  Furnace type size: furnace length is determined by production capacity, normally 30-60m.

(8)   Main external device

l  Set an uncoiler in furnace inlet

l  Set spray system in furnace outlet

l  Coiler