Boiler rooms

At the customers we meet with many types of steam, hot water and heat water devices. Against past steam is used for heating occasionally. Many companies are still using steam for production. For example food production: dairy, bakeries, breweries. Steam is needed also to produceplastics or heavy industry. Hot water and heat water pipes are mainly used for heating and for production of hot water. Nowadays, only a few companies have a portfolio of products, wich respect these differences. Chemical treatment depends on construction and pressure of steam boilers in which they are operated. Steam boilers are divided into low, medium and high pressure by the temperature and pressure ratios. By way of relief flue gases to water-tube and fire-tube. The surface of water and water-steam pipes which are surrounded by fuel gas form the heat transfer position of evaporator in the case of water-tube boilers. These boilers were used for cases of higher wattage above about 15t/hour. Today boilers are produced with high wattages and they are fire-tube. These boilers are characterized by their huge water space. Fire tubes rolled at the front of boiler (flue tubes) going through this water space. Fire tubes through which flows hot combustion gases from the fireplace, form the main heating surface of the boiler.

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Schema of fire-tube boiler

If you need steam immediately, it is better to use  the steam generators. They are preferred there, where the steam consumption is irregular and the long-term heat in the boiler cost a lot of money. However, they are compared to conventional boilers. They are very sensitive to perfect treatment and pre-treatment of water.

Boiler feed water:

Water quality pre-treatment is the main point for a good job. Without a good softening or osmosis boiler is not possible to operate a boiler for a long time. It is also necessary to service the pH of boiler feed water, usually in the values of 8.5 to 9.5. The temperature of boiler feed water should reach 105 oC in thermal degassing otherwise there is an opportunity of corrosion in the boiler. Chemicals dosing into supply tanks or sometimes for supply tanks have following tasks:

  • chemical degassing

Although we have good thermal degassing, it is also necessary to treat it chemically. It is usually based on a sulphite as oxygen scavengers. Current sulfite is sufficient if it has enough time for the chemical reaction with oxygen. Length chemical reaction depends on the temperature, the colder supply water, the longer reaction. Reaction can take two minutes. It can happen when we have a small supply tank, sulphite abundance, reaction doesn´t have to run over and it can appear the pitting. It is therefore wise to use a form of catalyzed sulfite, which is offered by some manufacturers worldwide and eliminate this problem.
Catalyzed form of sulphite is used in smart case. It is offered by some worldwide manufacturers and the problem is eliminated.

  • Removal of residual hardness

Hardness always remains even when a cation exchanger is well working. Hardness is not measurable by typical means, it thickens and precipitated calcium carbonate, limescale in a boiler. Therefore it is dosed  a phosphate, which reacts with residual hardness and produces sludge which is removed regularly continuous blow down. Phosphate disadvantage is its tendency to stick to the tube sheet and create deposits that as an insulating layer prevents effective heat transfer from the flue gas into the water. Today´s advantage is using polymeric products, which contain a phosphate and simultaneously polymer particle slurry coating, put into suspension, and diverts the blow down. At the same time will clean already clogged heat transfer surfaces. Fully polymeric product is based on organophosphate, residual hardness is not precipitated, but keeps it in solution.

Boiler water:

Water is thickened in water due the evaporation and it causes increasing pH, conductivity and alkalinity, and other parameters. pH should be between 10,5 to 12. Lower pH increases the risk of corrosion. At lower alkalinity also increases the risk of low OH alkalinity, which may create a risk of the boiler magnesium phosphate (black, sticky), or magnesium silicate (like glass), which is then very difficult to get rid of. Higher pH in turn could threaten the boiler alkaline embrittlement.

Another important parameter is the M-alkalinity, which should not exceed 1000mg / l. When value is exceeded it can cause in foaming of a boiler.
Too high phosphate concentration is that mistake too. Besides the enviroment being unnecessarily burdening. They can often be a source of fines for exceeding their limits in wastewater. They are also a source of sludge, which then clog the boiler.
If you just have a trouble with high phosphates in waste waters, it is very convenient to use a fully polymer treatment where the concentration of phosphorus is very low and also immeasurable commonly used laboratory wals.
We have to pay attention to the content of silicates, in the case if the boiler has a turbine. Concentration of silicates musn´t exceed 20 mg / l.
Silicates are transferred to the steam and it can cause clogging of turbine.
In some boiler rooms are still pay low attention to the efficiency of steam production.
Heat transfer is get worse with small deposits in tenths of mm on the tube plate. We can save up several percent of the annual rates for gas or other fuel if we clean it.
The next a little control parameter is thickening, by another name cycles of concentration. They show the amount of blow down losses. We lose not only water that goes to sewage, but also the heat that goes with blow down. You can save both adjusting concentration, and utilization of the residual heat.

In the case of chemical treatment of steam generators - don´t save money! Screw feeder, which leads the water to produce steam, has a very small radius, even the smallest error in the chemical treatment leads to scaling. There is no other way than to replace it when it is fauled. Generators also don´t usually have thermal degassing, and the temperature moves up to around 90°C in the supply feed water tank. In addition, they have a small feed water tank, and beside it is often missing automatic chemical dosing synchronized with doses of boiler feed water to the boiler.
All this cause that chemical reaction runs only a few seconds to remove oxygen and oxygen is not eliminated and it occuresto oxygen corrosion. Fully polymeric product type of organophosphate and also catalysed sulphite is good solution for this case.

Najdete nás

  • Starobělská 1063/13
    Ostrava – Zábřeh
    Česká republika 700 30
  • +420 702 181 700
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