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7.Secondary Plants& Services

 

7.1.Treatment Plants

7.1.1.Acid Vapours Wet Scrubber


The acid vapours absorbing and damping unit is placed inside the pre-treatment enclosure which contains all the pre-treatment tanks (the so-called tunnel).

This type of enclosure is fabricated in acid proof panels fixed to the carbon steel frame. As for the racks handling system inside the enclosure, there are two options:

1) Automatic crane inside the enclosure;
2) Automatic monorails outside the enclosure.

In both possibilities the walls and the roof of the acid-proof enclosure are produced of plastic panels supported by steel carbon frame. In the second option carbon steel frame weights about 75.000/80.000 kg. Suction tubes are built in polypropylene and are supported and contained by a metallic structure that should be anchored to the shed's roof.

Quantity of suction tubes 1
Expelling capacity 90,000 mc/hour
Tubes dimensions ø 1,500 x 12,000 mm
Compressed air pressure 6 Bar ½" pipe
Given power 60 HP

Supporting basement and pipes metal structure is fabricated from metal bars and plates. A centrifugal fan, entirely built in polypropylene with an impeller in ebonized steel, which is provided with a worm-conveyor built in two removable halves, complete with a 60 HP electric motor and vibration-damping accessories.

A cut-off gate, installed between the fan and the suction tube, wholly built in poly propylene, complete with axis and supports at the boards. Pneumatic control members include: slide solenoid valve, filter, lubricator and pressure reducer, flexible joints and accessories. An exhaust vertical chimney, cylindrical-shaped, consisting of flanged shafts, complete with a tangential clutch, cone-shaped bottom for steam trap, sampling taps, vibration-damping joints, gaskets and bolts and nuts in stainless steel.

The acid vapours absorbing system (wet scrubber) is combined with the previously described suction system. The contaminated air is forced to pass through a wetted packed bed where it meets up with the water counter flow. Then the air passes through a drop separator, before being released into the atmosphere. Water of counter-scrubbing, which is continuously enriched with acid, is not neutralized but replaced with fresh water, while the acidified one is reused in pickling tanks for filling.

Quantity of suction tubes 1
Expelling capacity 90,000 mc/hour
Vertical scrubber dimensions 2,400 x 9,000 mm
Compressed air pressure 6 Bar ½" pipe
Given power increasing 60 HP
Scrubbing fluid Service water
Control of water pH Included, only indicative
Absorption efficiency < 10 ppm HCl, < 15 ppm NH3

A pipe between the exhaust fan and the scrubber, entirely built in polypropylene, including vibration-damping joints, gaskets and bolts and nuts in stainless steel.


A scrubber, built in polypropylene, including:

A tank for recirculating water collection, entirely built in polypropylene, self-supporting, placed at the basement of the scrubber, complete with, for the recirculating pump and the ducts for level switches. Charge of 1.1/2" Pall rings, entirely built in polypropylene of special shape. Manholes for load and unload of packs, holding grids of charge and an internal reinforcement and support structure, built in polypropylene. Water injection system for counter flow with hollow-cone nozzles, distributing branches and accessories. Drop separator pack, entirely built in PVC, with shaped rectangular packs.

A dampening water recirculation system, including:

Powered vertical centrifugal acid-proof pump, with a 5 HP electric motor.
On-off and regulating valves, pipes, fittings in rigid PVC, spraying nozzles and accessories.

A system of scrubber Ph data reading, including a Ph electrode, probe and field transmitter. A control system of washing water level, installed in the scrubber, including acid-proof floating level switches for filling and safety, water detection solenoid valve and accessories.
Warm water heating coil, built in polypropylene pipes, for anti-freezing, complete with on-off and check valves, as well as accessories.


The electric system includes:

Part of general control board as described elsewhere. Electronic controls, installed and described in the general control board of the department. Materials and wiring diagrams between the control board and this group including connector blocks, channels, cables, flexible hoses and accessories.

7.1.2.Flux treatment unit

This unit offers, in comparison to conventional installations, the following advantages: Small size, doesn't require the sediment basin.
LESS Dross: the dross produced during the flux treatment is about 1/3 in comparison to that produced during the rinsing water treatment.
Simple and automatic process, totally controlled by PLC at each stage, the operation is cyclic with the possibility to adjust the cycle times
High efficiency, up to 150 kg of removed ferrous suspension per day
SUPREME FLUX PERFORMANCE: pre-treatment tanks are always kept clean, free from any sediment or suspension and with the right pH level, as a newly filled tank.
HIGHLY ECONOMICAL', thanks to the recycling of the chemical solutions you can diminish the flux salts purchase costs. Also encourages the reduction of waste products amount (ashes in the zinc kettle).
Minimum maintenance needed.

Project data

Production of galvanized steel 80.000 tons/ yr
Rinsing tank The solution is added to the pickling tanks
Average drain-off data(hypotetical calculation based upon the items with 3 mm thickness) 3 l/ton of hot-dipped items
Ferrous suspension to be removed –MAX REMOVED QUANTITY PER DAY – 100 kg Fe / day without rinsing 50kg Fe with rinsing
Possible zinc chloride re cycling exists

Treatment steps

1 oxidation / neutralization
2 filtering / dross thickening
3 thickened dross dehydration
4. exhaust and restart.

DESCRIPTION AND FEATURES

The plant has a self-supporting transportable skid with approximate dimensions:
LENGTH 2700 mm WIDTH 1200 mm HEIGHT 1600 mm

More precisely includes:

01. Reaction PP reinforced tank with metal frame lined with PP complete with 20mm cover
02. Exclusive system of blending, cycle control and reagents adding, composed of Venturiejector pump
03. Check valves on pipes for feeding and reagents supply
04. Process level sensors plus 1 safety sensor to be placed in the well
05. Pump kit includes: pump plus reagent dosing pumps - all pneumatically operated
06. Electric board IP55
07.PLC for controlling and monitoring of manual controls and automatic cycle
08.Air group distribution and regulation
09.Monitoring system and pH regulation
10. Dross drying system with air filter
11. Prepared for Ammonia - Hydrogen Peroxide dosage
12. Provision of basic operation with the following cycles: Ferrous suspension Removal–Filtration-neutralization only
13. Ability to combine a filter with automatic drain (not included)
14. Possibility to install remote module tele-diagnostics and alarms. (not included)

Connections needed:

Electricity three phase + neutral 400 V 32 A Compressed air 600 ltr / hour at 6 bar max – dry air Hydraulic NOT INCLUDED

Maximum distance from the tank 20 METER PVC DN40 Maximum distance reagent reservoirs PVC 3 METER DN12 Float with a filter 5 mm max at 30/40 cm from the bottom Re-launching 2-3 cm above the tank level (preferably side float)

FILTER - Cloths in PP - pneumatic double diaphragm pump 7 bar type Boxer 150 PHTTID

7.1.3.Rinsing Water Treatment Unit

This plant is identical to the above-described.

7.1.4.Acid Recycling Plant

1. TECHNICAL OVERVIEW OF THE INSTALLATION

The plant is pre-assembled in two 20' container size skids: one skid comprises the reaction section and the service equipment, the other one comprises the filtering section together with cake collection, rinsing and washing devices. The plant is plug-and-play designed, so it's ready to be put on a flat surface site, connected to the existing acid storage piping, with almost no erection job to do.

The plant is to be installed over ground, with no need of excavations or any civil work, because it has a built in drippings cath basin, capable of 1/3 of total volume of liquid processed.

Overall power requirement is 12 kW, 400V 50 Hz, 3F+N 32A.

Overall compressed air requirement is 1500 Nl/min @6 bar.
The plant also need a water supply, with no pressure requirements, for cake washing system.

1.1 FILTRATION UNIT

Used acid should flow through a filter-pump unit, specific for removal of solid impurities and oily substances. The plant has one working equipment, and a second stand-by system to be switched every 24 hr operation.

1.2 REACTION UNIT

Three heavy duty PP tanks designed to work as a gang, overall dimensions 1700 x 1700 mm approx., volume 2,5 m3 each, including multistage stirrer, level switches, loading/unloading flanges, chemical additive charging hopper.

All equipment has been designed to be corrosion proof.

1.3 SOLID SEPARATION UNIT

Supply include one heavy duty filterpress, having the following

Plates dimensions 1000 x 1000 mm
Nr. of plates 22
Filtering surface 20 sq.m.
Cake available volume500 lt.
Filtering pressure 6 bar
Squeezing pressure 4 bar
Power 2.5 kW

Filter press operation is fully automatic, PLC driven, and it allows to get a dry sludge with a dry content up to 60%.

Equipment features:

Automatic plates opening: a special corrosion resistant rubber-belt driven system provide quick and safe opening of the plates for cake discharge; membrane squeezing: operated with 4 bar compressed air ; countercurrent cake washing: the supply includes water tank, and diaphragm pump for cake washing. Washing water flow goes in a separate tank, to be recovered for reutilization.

corrosion resistant painting, 100 microns priming layer + 120 microns epoxy top coating. laser cut PP filtering clothes, for highest dimension stability with no risk of fraying. DN 80 center side feeding pipe, four DN 50 corner side filtrate discharge pipes, complete of connecting manifold and all valves, including pressure relief valve; compressed air diaphragm feeding pump, max 240 l/min;
safety shields alongside the plate pack, in order to avoid any liquid spraying toward operators; corrosion resistant PP lined cake discharge hopper;
complete control panel, with all safety devices and switches for equipment management. It includes automatic cake washing, air flushing, cake squeezing sequence management.

1.4 PIPING AND SERVICE DEVICES

Complete set of PVC pipes, valves (manual and air operated) and fittings for connecting the equipment.

The facility is equipped with built-in washing water storage, with automatic refilling, for perfect control of flushing water volumes.
The facility is also equipped with a 500 liters compressed air vessel, with all fittings and piping, in order to optimize compressed air requirements.

1.5 STEEL WORKS

Working area will be on the roof of the skids, that will be covered with gratings. For safe operation the facility is designed with stairs, handrails and guards.
Supply includes the drawings of all these steel works, to be manufactured on site by the customer. Optionally we could provide also steel works.

2. OPTIONAL FEATURES

2.1. ACID STORAGE ENGINEERING

If required, engineering of acid storage facility shall be supplied, not included in this offer.

3. OPERATION PROCEDURES

The machine should be operated by one operator. Procedures are as following: Reactor filling: one batch of 2,5 m3 of used acid should be loaded on the reactor through the dedicated pump. It will take around ten minutes; Reactor loading: according to regeneration parameters, a quantity of additive ranging from 100 to 250 kg should be loaded into the reactor. It will take about 20 minutes;
Reaction time: the reaction will take about 4,5 hours to be completed.
3 hours after the first loading, the second reactor should be loaded: during reaction time it will be possible to filter the pulp of the first reactor.
Filtering: filtering the pulp needs about 3 hours, including cake flushing and squeezing time.
In this way it's possible to start a new cycle in a reactor every three hours, making possible to reach up to 8 cycles per day..

7.1.5.White Fumes Enclosure



This absorbing system for white fumes is based on the principle of sealing action which is produced during the dipping of items in the zinc kettle, to reach the maximum absorbing efficiency.
The system is essentially composed of two parts: a fixed booth and the so called "suction unit", consisting of a suction pipe, an exhaust fan and of the waste fumes pipe. The filtering system will be described on the following pages.

Working principleBy a fixed booth to the furnace
Installed power 30 HP
Efficiency 70% to 80%
Suction flow rate60,000 m³/hour

A fixed booth applied to the furnace, including:
A metallic structure in metal sheets and stiffening tubular sections.The structure is composed of four scaffold poles standing at the four angles of furnace which sustain the wings of doors of headers and the fixed longitudinal panels. They are lodged in a seat that allows the easy removal of fixed panels by the bridge crane for maintenance works and in case of an emergency.

Two longitudinal panels, built in tubular sections and in metal sheets, complete with plates of stratified and plasticized glass with snap glazing profiles. Glasses are also installed in frames to be opened into wings with hinges to make easier the maintenance. A series of 4 lighted casings installed outside the hood, complete with unbreakable glass and 1 kW cleaning chest.
A suction system of white flue gases, including:

Working drawings and standard engineering of suction hood to be applied to the bridge crane of galvanizing in metallic structural works of section bars and metal sheets.

A suction inlet of white flue gases of cylindrical section in section bars and metal sheets, wholly warm zinc-plated, provided with a lip rubber gasket which helps to keep the tightness between the two ducts when they are coupled with an identical inlet put on the removable hood. Ducts of connection from the suction inlet to the ventilator, wholly warm zinc-plated, in flanged elements of rectangular and cylindrical section complete with vibration-damping joints.

A centrifugal suction fan of white flue gases with a worm-conveyor built in two removable halves, a special impeller in stainless steel with non-stick blades, complete with transmission members, a 50 HP electric motor and by a vibration-damping joint to the delivery head. A servo controlled throttle lock for the shutting off of suction during the idle phases with a pneumatic control complete with rods, a shaft, a pneumatic cylinder, a solenoid valve, a control limit switch and accessories.

A suction system of white flue gases, including:
Working drawings and standard engineering of suction hood to be applied to the bridge crane of galvanizing in metallic structural works of section bars and metal sheets.

A suction inlet of white flue gases of cylindrical section in section bars and metal sheets, wholly warm zinc-plated, provided with a lip rubber gasket which helps to keep the tightness between the two ducts when they are coupled with an identical inlet put on the removable hood
Ducts of connection from the suction inlet to the ventilator, wholly warm zinc-plated, in flanged elements of rectangular and cylindrical section complete with vibration-damping joints.

A centrifugal suction fan of white flue gases with a worm-conveyor built in two removable halves, a special impeller in stainless steel with non-stick blades, complete with transmission members, a 50 HP electric motor and by a vibration-damping joint to the delivery head. A servo controlled throttle lock for the shutting off of suction during the idle phases with a pneumatic control complete with rods, a shaft, a pneumatic cylinder, a solenoid valve, a control limit switch and accessories.

An exhaust stack into the atmosphere of the sucked air, self-supporting, to be anchored to the adjacent shed, wholly warm zinc-plated, built in self-supporting flanged shafts of metal sheets and stiffening plates, Ø1400.0 mm, for a total height of 14.0 mtr from ground level, including: a support basement and sampling taps, anchorage flanks to the adjacent shed and a small ladder applied to the stack, a trestle and a support gallery for the operator during the sampling, a flexible joint of connection to the ventilator, a tangential clutch, accessories and the output with a soundproofing device.

Hydraulic connections, including:

Materials and diagrams for the preparation and assembly of pipes, fittings, supports and accessories for the distribution of natural gas and of combustion air, as far as our supplied components are concerned. Synthetic products for the final paint of the various parts, including aluminum paint and enamels or pipes and accessories.


Electric system, including:

Part of general control board as described elsewhere. Electronic controls, installed and described in the general control board of the department. Materials and wiring diagrams for electric connections in this group including connector blocks, channels, cables, flexible hoses and accessories.Materials and wiring diagrams for electric connections between the control board and this group including connector blocks, channels, cables, flexible hoses and accessories.

The filter for white fumes is installed before the exhaust fan. The given electric power takes into account the increment value to be assigned to the suction fan for increasing losses due to the filter. To obtain a perfect and reliable work of this plant, it would be better to install the filter in a closed room, in order to maintain a certain steadiness of room temperature.

7.1.6.White Fumes Filter


Absorbing capacity 60,000 mc/hour
Working principle Pph elliptic baghouse filter.
Principle of counter-flow By hot air produced by the fan and Impulse injected.
Compressed air pressure6 Bar ½" pipe
Extra power 30 Kw
Filtering surface1,200 m2
Efficiencydust < 5mg/m³
Height from ground level6,000 mm.
Installation in a closed room

Dry bag house filter with elliptic bags in synthetic material, entirely painted by an accurate acid proof and abrasion-proof procedure, including:
A series of shaped-elliptic duty bags with a suitable element in steel wire with fixing plates. A device of bags purging with a 5 HP centrifugal fan and 20 kW heating batteries, installed in a movable truck with programming and vacuum gage. A lower fin for dust collection with a mechanized output in prearranged bags with a 3 HP motor.

A series of thermocouples for the temperature control with a double element and with a stainless steel sheath.A series of lip rubber gaskets and in ceramic fibre.
Additional metallic structures for the filter, including:
Support structures for the filter in steel work, including galleries, fixing frames, supports, gangways, railings and small ladder.

Hydraulic connections, including:

Materials and diagrams for the preparation and assembly of pipes, fittings, supports and accessories for the distribution of natural gas and of combustion air, as far as our supplied components are concerned.

Electric system, including:

Part of general control board as described elsewhere. Electronic controls, installed and described in the general control board of the department. Materials and wiring diagrams for electric connections in this group including connector blocks, channels, cables, flexible hoses and accessories.
Materials and wiring diagrams for electric connections between the control board and this group including connector blocks, channels, cables, flexible hoses and accessories.

7.2.1.Oil Separator

Expandable two-stage static oil separator with a 3.5 mc/hour flow capacity, produced in P.R.F.V. and designed to reduce at minimum the space.
The efficiency is very high thanks to its special constructive form that makes easier the separation of oils or other substances with a specific weight lower than water, that float towards the surface.

Before entering the separation area under a fixed cone, the inlet flow meets up with a chamber of such sizes that reduces the instantaneous speed to a value close to the floating speed. The flow never exceeds the speed of 3,5 mm/sec. (equivalent to the floating speed of linseed oil at 15°C) in the separation chamber.

To reach the surface, the oily particles flow into an inclined plane, composed of a cone, and tend to cling till reaching such size that allows the flotation upwards. At the output of the first stage there is a second closed cone, at the bottom of which the water for the output is collected at a much lower level than the discharge, making virtually impossible the outflow of oil (second stage).

There is also a chamber of oil collection where the discharge is in a upper position than the output. The different position is due to the different surface of the two chambers (separation and oil collection). All this allows the permanent discharge of accumulated oil without any intervention.

The oil separator is expandable with a modular pack that increases remarkably its performances. It's possible to empty completely the tank for a periodical cleaning. This apparatus is able to carry very high quantities of oil.

7.2.Service Equipment

7.2.2. Heat Economizer

Waste gases from the galvanizing furnace go through this heat economizer, which produces hot water for degreasing, pickling and fluxing heating units.

Temperature of waste gases380/550°C Capacity of heat regeneration 300,000 Kcal/hour Temperature of hot water 65(85)°C Given electric power4 HP

Frames and support basements of appliances in metal work painted with an acid-proof paint. Manifolds of delivery and distribution of hot warm water.Heat insulation of pipes within the economizer group, with preformed coverings.

The economizer is built in a metallic structural work, entirely lined with a non-conducting mattress, complete with two inspection doors. Heat exchanger with a tube bundle, that can be easily inspected and replaced, built in finned pipes and stainless steel sheets, including:

A double servo controlled flu damper with a proportional electro mechanic actuator complete with limiting load devices for the modulation and by-pass of combustion fumes, built in a rugged metal work and embedded in the waste-gas ducts .

Rotation shafts, bench supports, toothed wheels, counterweights and accessories. 3-way valve with mechanic actuator, on-off and safety valves, air vents and accessories for the preparation of hot water circuit.

4 straight thermocouples in stainless steel with a double element, complete with compensated cables for the temperature control of combustion fumes and of warm water.

System of hot water distribution for temperatures up to 85°C, including: Two centrifugal electric pumps with a back impeller and a reservoir for the recirculation of heating water.

On-off valves, air vents and whatsoever necessary for the organic functioning of the plant. A Hydraulic connections, including:

Water plant:

Materials and diagrams for the preparation and assembly of pipes, fittings, supports and accessories for the distribution of the service water, as far as our supplied components are concerned. Materials and diagrams for the preparation and assembly of pipes, fittings, supports and accessories for the distribution of the service water among the different units.

Plant of hot water:

Materials and diagrams for the preparation and assembly of pipes, fittings, supports and accessories for the distribution of warm water, as far as our supplied components are concerned. Materials and diagrams for the preparation and assembly of pipes, fittings, supports and accessories for the distribution of warm water among the different units.,

The electric system includes:

Part of general control board as described elsewhere. Electronic controls, installed and described in the general control board of the department. Materials and wiring diagrams for electric connections in this group including connector blocks, channels, cables, flexible hoses and accessories.

7.2.3.Fresh and Exhausted Acid Storage

All pre-treatment tanks are provided with a drain at the bottom and with two upper inputs, one to prime the fresh acid and the other for the service water. The fresh acid is poured in by a prearranged line connected to all the lines coming from the outside of the shed, where it is installed the launch pump. In this way the vehicle dispensing the fresh acid is connected directly to this external line. This place is protected with an acid-proof flooring and provided with connections to the service water, in order to perform the required washing. The waste water of these washings is conveyed to the pre-treatment pit, which contains all the tanks. Our supply includes all materials necessary to prepare and control the supply line for fresh acid.

The exhausted acid which should be transferred from the pickling tanks to the waste-acid dispensing vehicle by an electric pump connected directly to all the drains at the bottom of tanks and from here the waste acid is conveyed outside to the same starting place of the fresh acid.

Tanks are also all connected to the line of service water with PVC pipes.

Line for fresh acid distribution :
1" Line for exhausted acid discharge
2" Line for service water distribution
Electric power installed : 6 H.P

System of accumulation and dosage of the exhausted acid, including:

Support frame of launch pump, built in metal work and painted with acid-proof paint. Acid-proof horizontal centrifugal electric pumps with a back impeller complete with a 2 HP electric motor, entirely built in polypropylene. Delivery line in rigid PVC from the pump to storage, including valves, pipes, fittings, vibration damping joints, supports up to the point of destination, everything 2".

An alternative electric pump for exhausted acid dosage, with a changeable capacity, entirely built in polypropylene, complete with a 1 HP electric motor and accessories.

System of fresh acid accumulation and distribution, including:
Support frame of distribution pump, built in metal work, painted with acid-proof paint. Acid-proof horizontal centrifugal electric pumps with a back impeller complete with a 2 HP electric motor, entirely built in polypropylene.
Materials for the delivery line in rigid PVC including valves, pipes, fittings, vibration-damping joints, supports from the accumulation tank to pickling tanks of 1" type.

The electric system includes:

Part of general control board as described elsewhere.Electronic controls, installed and described in the general control board of the department. Materials and wiring diagrams for electronic connections between the control board and this group including connector blocks, channels, cables, flexible hoses and accessories.

7.2.4.Dross Extraction Vibrating Grab

The bucket allows to collect the dross from the surface of the galvanizing kettle in absolute safety for the operators and kettle. The equipment is mounted on the bridge crane and powered with 6-8 atm compressed air. It has the following characteristics:

Compressed air in delivery through a 1/2" pipe at 6-8 atm.
Electric motor vibrator Exists
Voltage 400 V – 50 Hz
Process of manufacture of shovelAISI 316 L
Sizes of shovel 700 x 500 mm
Length of handle 2700 mm
Carrying capacity 3 tons
Height of bucket 3,200 mm
Given power 4 HP

The casing of bucket is built in steel, is provided with a plate and eye bolts for the hook to the bridge crane.The double shovel is built in ARMCO metal sheet with holes for the dripping of melted zinc. The pneumatic cylinder for the bucket opens and locks with a suitable power.
The alternating movement is performed by the double pneumatic vibrator used to remove the liquid zinc. The directional handle equipped with a control push-button panel of bucket movements, is arranged in the upper part of the mechanism structure.

7.2.5.Pneumatic Zinc Pump

The said pump is used to transfer the liquid zinc from the galvanizing kettle into the suitable containers during the maintenance procedures or kettle replacement.

Carrying capacity 130 tons/hour pure zinc for 1 m
Pump power 3 HP
Power supply compressed air
Consumption of compressed air 2 mc/min at 6 Bar
Length of pump 3,300 mm

Centrifugal pump for the transfer of liquid zinc with a vertical shaft, produced in normal steel with the exhaust pipe of Ø 2.0". The pneumatic motor, cooled and powered with compressed air, coupled directly with the shaft of the pump.