• Product Introduction
  • Flue tube-smoke tube boiler vs. multi-tubular boiler
Advantages and disadvantages of Flue tube-smoke tube boiler
Comparison of advantages & disadvantages of double-effect condensing boiler & multi-tubular boiler
Comparison of operations of double-effect condensing boiler & multi-tubular boiler
  • Intermittent operation (On-Off)
    of tubular boiler (stepped evaporation by 5 units x 2 tons of tubular boilers)
  • Proportion operation of double-effect condensing boiler
    (10 tons of condensing x evaporation by proportional control)
  • In a tubular boiler, due to the extremely small amount of retention quantity, steam is generated within 5 minutes. On the contrary, in a condensing boiler, due to the large amount of retention quantity, steam is generated 30 minutes after ignition. The condensing boiler is disadvantageous as it needs to be preheated 25 minutes earlier and takes more fuel to preheat the boiler supply water. However, this phenomenon occurs only once when initially operating the boiler. When stopped at night, instead of blowing off the high temperature water closing the emission gas damper, it can reduce the initial steam generation time to 8-10 minutes due to the remaining heat reserved until the next morning.
  • The extended combustion during the operating time of initial 25 minutes of a condensing boiler can be momentarily saved in the boiler supply water instead of wasting it into the air.
  • In a tubular boiler, due to the extremely small amount of retention amount, carry over can occur due to extremely rich supply water. During night stop and pause, supply water needs to be blown off, generating heat loss. Frequent cold starts in the morning can reduce the lifetime of the boiler.
Does a large capacity boiler have more heat loss compared to the tubular boiler?
Does the condensing boiler that takes 30 minutes to generate steam have more heat loss compared to the tubular boiler that takes 5 minutes?
  • Evaporation and pressure change curve of double-effect condensing boiler during pause
  • In a tubular boiler, due to the extremely small amount of retention quantity, steam is generated within 5 minutes. On the contrary, in a condensing boiler, due to the large amount of retention quantity, steam is generated 30 minutes after ignition. The condensing boiler has a disadvantage as it needs to be preheated 25 minutes earlier and takes more fuel to preheat the boiler supply water. However, this phenomenon occurs only once when initially operating the boiler. When stopped at night, instead of blowing off the high temperature water closing the emission gas damper, it can reduce the initial steam generation time to 8-10 minutes due to the remaining heat reserved until the next morning.
  • The extended combustion during the operating time of initial 25 minutes of a condensing boiler can be momentarily saved in the boiler supply water instead of wasting it into the air.
  • In a tubular boiler, due to the extremely small amount of retention amount, carry over can occur due to extremely rich supply water. During night stop and pause, supply water needs to be blown off, generating heat loss. Frequent cold starts in the morning can reduce the lifetime of the boiler.
Due to large amount of retention quantity, the flue tube-smoke tube boiler is stably operated in many load changes.
A large boiler does not necessarily suggest a higher fuel cost and electricity cost.
  • Although the efficiency of the tubular boiler is over 95%, this was measured during continuous operation of testing the boiler for over 1 hour. The tubular boiler is a small boiler with an extremely small retention quantity and evaporation capacity. Slightly opening and closing the steam value due to change in load causes harsh pressure fluctuation resulting in the repetition of dozens of shut downs per hour or tens of thousands of shut downs per year. The losses due to this are as follows.
  • It takes three times (same as vehicle) more ignition fuel than normal operation, and purge loss is over 6% of total used fuel. The starting current of the blower and water supply pump is 5 times that of normal operation, increasing electricity use. This can be easily understood through this example: a rice pot’s purchasing cost, fuel loss, scorched rice loss, labor loss and inconvenience are compared when cooking rice for 100 dining people by installing 3 units of rice cookers for 33 servings and 20 units of rice cookers for 5 servings.
  • The double-effect condensing boiler controls the gas amount through proportional control according to pressure change with over 100% operation efficiency; also the inverter saves fuel and electricity by combusting the burner while continuously controlling the number of rotations of the blower. Also, by detecting the speed of supply water changing with the amount of steam evaporation, it supplies water by proportional control of continuous water supply equipment that controls the number of rotations of the supply pump, saving electricity and supplying quality steam.
Have you thought about the A/S cost?
  • Tubular boiler water tube rupture due to scale
  • As the tubular boiler repeatedly shuts off a dozen times per hour or tens of thousands of times per year, the burner, blower, water supply pump and measuring equipment frequently fail and have short lifetimes. Due to the small heating surface and retention quantity, incorrect water treatment may result in frequent rupture of the water tube. How much A/S cost and replacement cost will it take if several dozens of these boilers are installed? As an example, this is proved by the fact that the A/S profit is greater than the company’s boiler sales profit and there is much more production personnel of A/S.
  • Due to the large heating surface (5 times that of tubular) and retention quantity (20 times that of tubular), the double-effect condensing boiler is unaffected by water quality and has a longer lifetime by adopting an automatic proportional control combustion and continuous water supply method. Also, as the tube can be conveniently replaced up to 4 times, normal water treatment can ensure usage for over 20 years. As a large boiler capacity allows less installed units and continuous operation, burner, blower, water supply pump or measuring equipment failure is less frequent and there is seldom any A/S cost.