Production and heating boiler house with boilers DKVR-6.5-13

Contents

Contents

Introduction

1 Description and calculation of boiler room thermal diagram

1.1 Brief description of DKVR-6,5- boiler unit

1.2 Description of boiler room thermal diagram

1.3 Calculation of boiler room thermal diagram

1.4 Selection of number of boilers to be installed

2 Selection of water treatment equipment

2.1 Composition of natural water

2.2 Water Quality Indicators

2.3 Water treatment for steam boilers

2.4 Selection of source water treatment scheme

2.5 Selection of sodium-cationite filters

2.6 Selection of sodium-chloro-ionite filters

2.7 Choice of Salt Solvent

2.8 Deaerator Selection

3 Calculation and selection of auxiliary boiler room equipment

3.1 Pump selection

3.2 Selection of heat exchangers

3.3 Selection of Continuous Purge Separator

4 Calculation and selection of traction equipment

4.1 Description of air supply and smoke removal scheme

4.2 Calculation of combustion product volumes and boiler gross efficiency

4.3 Selection of traction equipment

5 Boiler house fuel supply

5.1 Description of gas control unit

5.2 Composition and functions of GRU equipment

6 Boiler room automation

6.1 General Automation Requirements

6.2 Parameters to be monitored

6.3 Boiler Safety Automation

6.4 Alarm

6.5 Automatic regulation

7 Description of architectural and construction part of boiler plant

8 Heating and ventilation of the boiler room

9 List of sources used

Introduction

In this course work, the project of a production and heating boiler house located in Vladimir on the Klyazma River was completed. Natural gas of the second line of the Stavropol-Moscow gas pipeline is used as fuel.

The boiler room is used to supply steam to an industrial enterprise and to heat a residential area. Heat loads for technological needs - 9 tons of steam per hour; for heating and ventilation - 16 GJ/hour; on GVA - 8 GJ/hour.

Condensate is returned from production with temperature tcond.tech. = 75 ° С in the amount of 65%

Boilers of DKVR6,513 grade manufactured by Biysk Boiler House-Water are used in the boiler room.

The heat supply of the district is carried out according to a two-tube closed scheme. Design parameters of coolant: supply pipeline - 130 ° С; return pipeline - 70 ° С.

2 Selection of water treatment equipment

The reliable and economical operation of the boiler plant depends to a large extent on the quality of the water used to feed the boilers.

Sources of water supply for feeding boilers can be ponds, rivers, lakes (surface water intake), as well as groundwater or artesian water, city or village water supply. Natural waters usually contain impurities in the form of dissolved salts, colloidal and mechanical impurities, therefore are unsuitable for feeding boilers without preliminary purification.

2.1 Composition of natural water

The solids contained in the water are separated into mechanically suspended impurities consisting of mineral and sometimes organic particles, colloidal dissolved substances and true solutes. The amount of substance dissolved in a solution unit (water) determines the concentration of the solution and is usually expressed in milligrams per kilogram of solution (mg/kg).

Water, like any liquid, can dissolve only a certain amount of a substance, forming a saturated solution, and an excess amount of the substance remains undissolved and precipitates.

There are substances that are well and poorly soluble in water. Substances that are highly soluble in water include chlorides (salts of hydrochloric acid) CaC12, MgC12, CaC1, poorly soluble - sulfides (salts of sulfuric acid) CaSO4, MgSO4, N3SO4 and silicates (salts of silicic acid) CaSiO3, MgSiO3. The presence of sulfides and silicates in the water leads to the formation of solid scale on the heating surface of the boilers.

The solubility of the substances depends on the temperature of the liquid in which they dissolve. There are substances in which solubility increases with increasing temperature, for example CaC12, MgC12, Mg (NO3) 2, Ca (NO3) 2, and in which, for example, CaSO4, CaSiO3, MgSiO3.

Water treatment for steam boilers

The initial data for selection of pre-water treatment equipment is:

amount of boiler blowdown;

carbon dioxide content in the steam;

relative alkalinity of boiler water.

Water treatment for hot water boilers includes the following main stages:

removal of suspended particles;

removal of iron;

softening, prevention of scale formation;

prevention of corrosion (removal of oxygen and carbon dioxide from supply water using deaerators of various structures. The use of a deaerator makes it possible to significantly reduce the content of free oxygen (up to 0.02 mg/kg), the rest should be bound by a chemical method).

2.3.1 Removal of mechanical impurities using filters

Mechanical filters of various designs are used to remove precipitated (sand, iron oxides, CaCO3 salts and other heavy particles) and suspended particles (fine clay, dirt and organic matter).

With minor mechanical contamination (up to 5.0 mg/kg), it is possible to install compact filters of the cartridge type (replaceable or flushing), the main advantages of which are small dimensions, high speed and filtration depth.

If the suspended particles in water are more than 15 mg/l, it is advisable to perform filtration on pressure filters with a combined layer (sand + anthracite).

The filtered particles are removed from the bed by countercurrent washing as necessary.

For the designed boiler house, pressure filters with a combined layer are used, since the use of cartridge filters is impractical (the content of suspended substances in the clarified water is 8.0mg/kg).

2.3.2 Softening of water by ion exchange

The most common method of purifying water for subsequent use as a heat carrier is ion exchange techniques. The essence of these methods is that water is filtered through a special material called ionite. This material has the ability to vary the ionic composition of the water in the desired direction. From an electrochemical point of view, the ionite molecules are a solid electrolyte. Depending on the charge carried by the diffusion layer, the ionites are separated into cationites and anionites.

The most common cationites are: sulfogol and ion-exchange resins KU 1, KU 2. The most common anionites are AN31, AB-17, AB18. Depending on the quality of the source water and the requirements for the quality of the treated water, the following ion exchange methods are used in practice: sodium cation, hydrogen-cation, chlorination, ammonium-cation.

Na-cation is the most common method of treating water. It consists in filtering it through a layer of cationite containing an exchange sodium ion.

The following reactions take place:

Ca (HSO) 3 + 2NaR CaR2 + 2NaHCO3

Mg (HSO) 3 + 2NaR MgR2 + 2NaHCO3

CaCl2 + 2NaR СаR2 + 2NaCl

MgSO4 + 2NaR MgR2 + Na2SO4

As can be seen from the above reactions, the calcium and magnesium salts contained in the water enter into exchange reactions with cationite, replacing sodium in it and thereby softening water. Instead of calcium and magnesium salts, an equivalent amount of readily soluble sodium salts is formed in the treated water. Therefore, the salt content during water treatment is not reduced, but slightly increased. The alkalinity of the water and the anionic composition do not change during Nacationation.

The operation of the cationite filter is reduced to the following sequential operations: softening, loosening, regeneration, washing.

The main operation of the process is softening. With softening, the exchange of Ca2 + and Mg2 + cations with Na + cations occurs. As the ion exchange passes, the cationite is depleted and compacted, the exchange reactions are slowed down until the Ca2 + and Mg2 + cations slip into the treated water. To restore the exchange capacity of cationite, it is loosened and regenerated. Flaking is carried out by the return flow of water supplied from the tank located above the filter, or by means of a pump. Regeneration is carried out with a solution of culinary salt NaCl. The last step is to wash the cationite from the residual regeneration products.

In practice, two water softening schemes according to the Nacation method are used: single-stage and two-stage.

One-stage Nacationation can produce water with residual hardness up to 0.1 mheq/kg. If it is necessary to soften the water more deeply (up to 0.01-0.02 mheq/kg), two-stage (sequential) Nacationation should be used.

The number of cation stages is determined by the requirements for treated water; so for steam shielded boilers where deep water softening is required, it is advisable to use a two-stage Nacation scheme; for hot water supply, partial softening of water is required, one cation stage is sufficient.

H-cationation. Treatment of water by H-cation consists in its filtration through a layer of cationite containing hydrogen cations as exchange ions. The reactions in the hydrogen filter are reduced to replacing the Ca2 + and Mg2 + and Na + cations with a hydrogen cation. The following chemical reactions take place:

Ca (HCO3) 2 + 2HR CaR2 + 2H2O + CO2

Mg (HCO3) 2 + 2HR MgR2 + 2H2O + CO2

CaCl2 + 2НR CaR2 + 2HCl

MgSO4+2НR MgR2 + H2SO4

NaCl + НR NaR + HCl

Na2SO4 +2НR 2NaR + H2SO4

2HR + Na2SiO3 2NaR + H2SiO3

Therefore, the salts (sulfates, chlorides, etc.) present in the water are converted during the ion exchange into acids (sulfuric, hydrochloric, etc.), i.e., the treated water has an acidic reaction (pH7), which is unacceptable. Therefore, H-cationation is always combined with Nacationation, which causes the alkaline reaction of the treated water.

Operation principle of Nkathionite filter is similar to operation of Nkathionite filter. The filter is regenerated with sulfuric acid solution.

The following HNacation schemes are distinguished:

HNaCation with "hungry" regeneration of filters;

parallel HNacation;

sequential HNacation;

joint HNaCation.

H-Na-cation with "hungry" regeneration of filters is used to treat water with increased carbonate hardness with a relatively low content of sodium salts.

Parallel HNaCation is used when the water supplied to the filters has a LCD of 0.5 Zho;

c _ (SO _ 4 ^ (2-)) ^ 〖 + c 〗 _ (Cl _ ^) ^ 〖 + c 〗 _ (NO _ 3 ^) ^ < 7mg-eq/kg

and when it is necessary to obtain softened water with a given residual alkalinity of not more than 0.35 mgeq/kg.

Sequential HNaCation is used to treat highly mineralized waters with salt content above 1000 mg/kg at LCD < 0.5 Zho and at

c _ (SO _ 4 ^ (2-)) ^ 〖 + c 〗 _ (Cl _ ^) ^ 〖 + c 〗 _ (NO _ 3 ^) ^ < 7mg-eq/kg

Joint HNaCation is used when the sum of strong acid anions in the water supplied to the filters does not exceed 3.5 MHeq/kg and when the alkalinity obtained under this scheme (Schost = 1-1.3 MHeq/kg) does not cause a noticeable increase in boiler blowdown above the established standards.

Na-Cl ionization. The NaClionite method is based on softening of water with simultaneous reduction of alkalinity and is carried out by sequential filtration of treated water through the first stage NaCationite filter, the second stage Clanionite filter and then the second stage Na cationite filter.

The second Nacationation stage is usually combined in one filter with Clionation, at the bottom cationite is loaded, and a strongly basic anionite of type AB - 17 is loaded on top.

In this method, cationite and anionite are regained by table salt NaCl (Na + regenerates cationite, Cl - anionite). In the filters of the first stage, water softens by reactions. In the second stage (in the combined NaClionite filter) in the anionite layer, anions SO42, NO3-, NO2, HCO3- contained in water are exchanged for chlorine, and in the cationite layer "slipped" hardness cations are exchanged for Na +.

The following reactions take place in the anionite:

Na2SO4 + 2AnCl AnSO4 + 2NaCl

NaNO3 + AnCl AnNO3 + NaCl

NaHCO3 + AnCl AnHCO3 + NaCl

By NaClioning water, the hardness of water can be reduced to 0.01 mheq/kg and the alkalinity to 0.2 mheq/kg .

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