The quality of boiler feedwater is an important determinant of safe boiler operations and it should be monitored to maintain the quality within safe working limits. Boiler feedwater is treated to protect the boiler from two basic problems: the buildup of solid deposits on the interior or water side of the tubes, and corrosion.
The high heat transfer of the boiler requires good medium. With the improvement of boiler in the production technology and intelligenlization, gas-fired boilers have more strict requirements for boiler operation medium in order to improve the boiler operating performance, reduce boiler failures and costs.
Gas-fired hot water boilers require high-quality water to improve the boiler performance and extend the service life. If the boiler uses the tap water of water which contains a lot of impurities, magnesium and calcium ions in the water will form white precipitates when the water is heated at high temperatures, which can cause the scaling problem to reduce the heat transfer efficiency of the boiler and bring hidden dangers of the boiler safety.
The food processing needs the steam or hot water to assist the production and improve the efficiency. Usually, the food plant needs the small tonnage boiler, so the coal-fired boiler is not recommended.
The gas-fired hot water boiler heats up quickly and has the high thermal efficiency. It is widely used in the heating industry and production. What are the maintenance methods of the gas-fired hot water boiler?
The steam boiler in the packaging plant is mainly used in the heating process before the raw paper is made into cardboard. In brief, it is using steam which contains no water in the drying process to improve the production efficiency and product quality of packaging cartons. As a result, it has high requirements for the steam and steam boiler, such as temperature, water content, rated evaporation capacity per unit time, etc., which are important parameters in the boiler selection.
1) Set up the air preheater. One of the most effective measures to improve the thermal efficiency of thermal oil heater is to use an air preheater for heat recovery. 2) Use waste heat boiler for heat recovery. The waste heat boiler uses the waste heat in the flue gas exhausted from the thermal oil heater to heat water or generate steam.
Influencing factors of slagging on heating surface of boiler
(1) Ash characteristics of pulverized coal
Generally, the softening temperature ST of ash is used as the main indicator of slag formation. Coal with low ash melting point (ST<1200℃) is easy to slag. In addition, the slagging index also includes: silicon ratio, alkali-acid ratio, slagging index, limit viscosity and so on.
（2）Aerodynamic characteristics in the furnace
Improper air flow organization leads to flame center deviation, and the pulverized coal air flow flame adheres to the wall, causing local slagging of the water-cooled wall;
Improper air flow organization, forming flue gas retention vortex area and forming a reducing atmosphere (with CO), reducing the ash melting point and increasing the possibility of slagging.
Excess air coefficient: When the excess air in the furnace is too small, a reducing atmosphere may be generated, and the tendency of slagging will increase accordingly.
（3）Influence of boiler heat lo
