Industrial building in the city of Yaroslavl

Contents

1. Source Data

2. Brief description and description of the room

3. Internal and external air parameters

4. Determination of heat losses

5. Heat transfer from equipment and materials

6. Compiling Heat Balance Table

7. Determination of harmful emissions by individual workshops

8. Drawing up a table on hazards

9. Local suction calculation

10. Calculation of air exchange during general exchange ventilation

11. Establishment of the air balance table

12. Technical solutions for air terminals

13. Calculation of air terminals

14. Calculation of calorifers

15. Calculation of heat curtains

16. Calculation of deflectors

17. Design and aerodynamic calculation of ventilation systems

18. Selection of ventilation equipment

19. List of applied literature

1. Initial data

In this course project, it is required to design a ventilation system for an industrial building located in the city of Yaroslavl. The building is divided into two sections: thermal and mechanical repair .

1. The thermal section is located in axes 1-4 and has the following equipment:

- Electric furnace - 80 kW, furnace temperature 1050 0С, opening area 0.32 m2.

-2 hardening and degreasing baths, dimensions 2100700, 70 0С.

-Electrode-salt furnace diameter 1.2 m, furnace height H = 0.6 m, furnace temperature 1050 0С .

- Also, 750 kg of metal from 1050 0С is cooled in the thermal section, and 1300 kg of metal - 31 0С is imported.

2. The repair and mechanical section is located in axes 58, it is divided into a procurement compartment and a welding compartment .

In the procurement compartment at 2 stations, carbon steels with a thickness of 4 mm are heat cut, with a cutting speed of 1.8 m/min: at the same time, iron oxide is released in the amount of 0.45 gr. Per 1 meter of cut length with a thickness of 1 mm.

There are several types of welding in the welding compartment:

-2 manual welding stations using ANO4 electrodes, electrode consumption - 7 kg/h, at the same time welding aerosol 5 gr/h, MnO 0.6 gr/h is released, which are removed by the Chernobezhsky panel 900 * 645 with a capacity of 3100 m3/h;

-1 semi-automatic welding station in CO2 medium using PPAN4 wire, wire consumption 5 kg/h; wherein HF is released in an amount of 1.95 gr/h;

-1 post of automatic welding under flux (melted), wire flow rate is 3.5 kg/h; wherein HF is released in an amount of 0.1 gr/kg of consumable material and MnO in an amount of 0.07 g/kg;

-1 gas welding station; acitelene consumption is 6 kg/h, where nitrogen oxide is released in an amount of 22 g/kg per 1 kg acitelene.

2. Brief description and description of the room

The production room is divided into two thermal and mechanical repair sections.

Thermal area:

Production processes in the thermal workshop are characterized by a significant variety of operations depending on the requirements for parts. Key operations include:

- annealing and normalization of products; this operation is carried out by heating to 800900 0C to give the metal a uniform structure and uniform hardness; heating is carried out in electrodisolar baths with molten sodium chloride or barium chloride. In chamber or muffle furnaces with subsequent cooling in air.

-Quenching of articles is to give the articles the required hardness, it is carried out by heating up to 750850 0C with subsequent rapid cooling in water or oil baths.

- release of articles in order to relieve internal stresses in parts formed during hardening.

-cementation is the process of enrichment of the surface layer with carbon, proceeds at 9009500C in furnaces in a medium containing gases saturated with carbon

The following hazards are identified in the thermal workshop:

1.convective and radiant heat from heated surfaces of furnaces, baths and from processed products.

2. Radiant heat from loading holes and from open surfaces of furnaces and salt baths.

3.water vapour and oil vapour from water and oil quench baths.

4. Gases (combustion products) containing carbon monoxide, sulfurous gas, smoke, as well as various gaseous compounds.

5. Dust, metal scale during forging and coal - lime dust, which is part of carbonizer.

All released hazards are localized with the help of shelters and local suction, while air is compensated by inflow into the working zone. General exchange ventilation is provided for mechanical from the upper zone.

2. Repair and mechanical section:

Welding, cutting and surfacing operations are carried out in the welding compartment. As a result of these operations, welding aerosol, manganese and its oxides, nitrogen oxides, hydrogen fluoride and other hazards are released into the room.

Main types of welding works:

-electrical automatic welding and surfacing under flux layer. Flux is a special protective compound. In this welding method, the welding arc is protected from air by a layer of flux and molten slag. Flux prevents metal spattering and shields arc radiation. The main

hazards: heat, fluorine connections and welding aerosol

-electrical semiautomatic welding in the environment of protective gases, carbon dioxide as such a medium. This type of welding differs in that the welding arc and the melting zone are protected by a gas shell. This is the most common type of welding. Main hazards: carbon monoxide and welding aerosol. All types of welding in the environment of protective gases are accompanied by ozone release and intense ultraviolet radiation.

- contact electric welding; happens point, butt. Stainless steel, non-ferrous metals and alloys are welded with this type of welding. With spot welding of carbonaceous steels, a small number of hazards are released in the air; when welding parts from non-ferrous metals, the number of aerosols significantly increases (almost doubles).

- heat cutting of metals, most common acetylene-oxygen cutting. Carbon monoxide and nitrogen oxides are released during cutting. Thermal cutting of alloyed steels is accompanied by significant heat generation.

Since the repair and mechanical workshop treats metals with liquefied gases, and local suction is not arranged, general exchange ventilation is organized in this way: 2/3 of the air is removed from the lower zone mechanically, 1/3 of the air from the upper zone using natural ventilation.

For manual welding, welder tables equipped with built-in fans are used. The overpressure in the pressure pipe 0.3 kPa is sufficient to release contaminated air into the atmosphere outside the workshop with a duct network of not more than 2530 m. The capacity of one fan is 1800 m3/h. When installing two or more posts that are not equipped with built-in ventilation, it is advisable to combine them into a common exhaust system with a mechanical urge. Aerosols formed during operations at automatic and semi-automatic welding units are removed by slit-like local suction pumps located directly at welders' places.

12. Technical Solutions for Air Distribution

It is recommended to provide supply of supply air during welding and cutting at non-stationary places concentrated from the upper zone with the use of air distributors, which allow adjusting the direction of the air medium in the vertical plane, ensuring air mobility of not more than 0.5 m/s at the point of jet penetration into the working zone.

In workshops where local exhaust is carried out at stationary places, it is recommended to supply air dispersed into the working zone, ensuring air mobility at the working place of at least 0.3 m/s.

The thermal workshop has large heat losses, so it is recommended to supply plenum air mechanically through plenum nozzles to the working area.

And perform natural plenum ventilation through window framugs. The released harmful substances are removed by local suction, mechanical exhaust ventilation is carried out from the upper zone, and natural ventilation is carried out through deflectors.

In the repair and mechanical workshop, it is recommended to provide supply of supply air concentrated into the upper zone using air distributors that allow adjusting the direction of the air jet to ensure air mobility in the working zone 0.3-0.9 m/s. Natural plenum and exhaust ventilation is carried out through deflectors with the exception of the cold period. Mechanical exhaust ventilation is carried out 2/3 from the lower and 1/3 from the upper zone.

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