The principle of operation and advantages of solid fuel pellet boilers


For the pri­vate sec­tor, hous­es of sub­ur­ban con­struc­tion, the autonomous heat­ing sys­tem plays a spe­cial role. For the cat­e­go­ry of cit­i­zens who use gas boil­ers, there are no spe­cial ques­tions. The sit­u­a­tion is more com­pli­cat­ed for the cat­e­go­ry of the pop­u­la­tion that is forced to use sol­id fuel heat­ing appli­ances for home heat­ing. For sol­id fuel boil­ers, wood or coal is tra­di­tion­al­ly used as the main fuel resource. How­ev­er, recent­ly such type of organ­ic fuel as pel­lets is gain­ing pop­u­lar­i­ty. Sol­id fuel pel­let boil­ers pro­duced today are pow­er­ful, eco­nom­i­cal and easy-to-use heat­ing devices.

Due to its per­for­mance, this type of heat­ing equip­ment is able to com­pete with gas heat­ing. For the cen­tral and north­ern regions of the coun­try, rich in for­est resources, the pro­duc­tion of pel­lets is one of the sources of income for wood­work­ing enter­pris­es. There­fore, if you have a real oppor­tu­ni­ty to get con­stant access to this type of sol­id fuel, bet on pel­let boil­ers. You won’t go wrong!

Read also about pel­let stoves.

Some information about pellets. What it is?

Pel­lets are cylin­dri­cal gran­ules 5–7 cm in size, made from wood waste. The diam­e­ter of such a gran­ule is slight­ly more than 6–8 mm. The size of the gran­ules is affect­ed by the qual­i­ty of the raw mate­ri­als used and the method of pro­duc­tion.

Under pres­sure, wood raw mate­ri­als are com­pressed, due to which a high den­si­ty of the sub­stance is achieved. Gran­ules, unlike wood, sink in water. In the man­u­fac­tur­ing process, the required mois­ture con­tent of the com­po­si­tion is reached, not more than 10%. Such strict para­me­ters for the fin­ished prod­uct are caused by the desire to achieve max­i­mum results in the com­bus­tion process. Long-burn­ing boil­ers, pyrol­y­sis-type units are very will­ing to use pel­lets as the main type of fuel.

Impor­tant! When choos­ing a heat­ing boil­er for your­self, eval­u­ate in advance from which sup­pli­er you will receive fuel. Pel­lets from dif­fer­ent man­u­fac­tur­ers dif­fer not only in size, but also dif­fer in the com­po­si­tion of the raw mate­ri­als. Oth­er­wise, the boil­er will oper­ate unsta­bly, giv­ing out dif­fer­ent tech­no­log­i­cal para­me­ters each time.

In fur­ni­ture fac­to­ries and wood­work­ing enter­pris­es, such waste occurs dai­ly, and in huge quan­ti­ties. Abroad, this has long been used, using wood waste as a fuel raw mate­r­i­al. As a rule, for the man­u­fac­ture of this fuel, main­ly soft­wood-based pro­duc­tion waste is used. The cost of such prod­ucts is not high. Raw mate­ri­als for pro­duc­tion are always avail­able in suf­fi­cient quan­ti­ties.

Less often, fur­ni­ture pro­duc­tion waste is tak­en for man­u­fac­tur­ing, where expen­sive types of wood are more often used. Such pel­lets burn bet­ter and last longer. The only neg­a­tive that is obvi­ous in this case is the high price of such fuel.

Today, waste from the main prod­ucts of agri­cul­ture and the food indus­try is active­ly used for the man­u­fac­ture of fuel pel­lets. Husks from sun­flower seeds, the remains of corn cobs are excel­lent raw mate­ri­als for burn­ing.

The main advan­tage that pel­lets have is full com­bus­tion in the fur­nace of boil­er equip­ment. This type of fuel has a high calorif­ic val­ue, which is sim­i­lar to the com­bus­tion of coal. If it is pos­si­ble to use pel­lets all the time, why not take advan­tage of this. What to give pref­er­ence to a pel­let unit or a sol­id fuel boil­er in a clas­sic ver­sion, choose the first option.

On a note: accord­ing to spe­cial­ists of heat­ing engi­neers, a pel­let boil­er is more eco­nom­i­cal. The effi­cien­cy of such a unit is 1.5–2 times high­er than any oth­er sol­id fuel boil­er equip­ment.

The principle of operation of the pellet boiler

What is the dif­fer­ence between a heat­ing device that works on pel­lets and what are its main design fea­tures, let’s take a clos­er look.

At first glance, this type of equip­ment may seem sim­ple and unpre­ten­tious in oper­a­tion. How­ev­er, it only seems so. A mod­ern sol­id fuel pel­let boil­er is a high-tech prod­uct equipped with all the equip­ment, devices and mech­a­nisms relat­ed to this tech­nique. It should be said right away that the key fac­tor for the sub­se­quent eval­u­a­tion of the heat­ing appa­ra­tus is the capac­i­ty of the fuel bunker. The larg­er the hop­per, the longer the heat­ing device will work with­out human inter­ven­tion.

The whole process of oper­a­tion of the boil­er on pel­lets can be con­di­tion­al­ly divid­ed into the fol­low­ing stages:

  • stage one, fuel sup­ply;
  • stage two, the com­bus­tion process;
  • heat trans­fer process.

The heat­ing boil­er itself works as fol­lows. The fuel in the bunker is fed into the com­bus­tion cham­ber auto­mat­i­cal­ly, due to the screw trans­mis­sion, i.e. in por­tions. As it burns, new pel­lets are con­stant­ly fed into the fur­nace, due to which the com­bus­tion process is con­stant­ly main­tained. Pel­lets enter­ing the fire­box burn out com­plete­ly, which min­i­mizes the for­ma­tion of ash and soot.

In the future, the design of this type of boil­er equip­ment will dif­fer from tra­di­tion­al ideas about the prin­ci­ple of oper­a­tion of sol­id fuel units. The com­bus­tion process main­ly takes place not in the com­bus­tion cham­ber itself, but on the burn­er, which has a cer­tain shape and design. As soon as the burn­er stops receiv­ing fuel, the com­bus­tion process auto­mat­i­cal­ly stops. Those. if you cal­cu­late in advance the vol­ume of fuel need­ed to heat the room, you can achieve almost com­plete auton­o­my of the entire process.

On a note: burn­ers in pel­let boil­ers are of two types: retort (vol­u­met­ric com­bus­tion) and flare.

Burn­ers in a sol­id fuel pel­let boil­er are the main oper­at­ing mech­a­nism. Sup­plied under high pres­sure, due to the oper­a­tion of the super­charg­er and the pres­ence of noz­zles, the air con­tributes to the high inten­si­ty of fuel com­bus­tion. Dur­ing oper­a­tion of the boil­er, the heat­ing tem­per­a­ture reach­es 4500FROM.

A retort burn­er is a device in the form of a bowl, in which there are lon­gi­tu­di­nal holes (noz­zles) on the sides. Air enters through these holes, on which the inten­si­ty of com­bus­tion depends. Depend­ing on the design of the unit, pel­lets enter the bowl from above or are pushed out due to the oper­a­tion of the auger from below. In this case, com­bus­tion occurs. The whole process, tak­ing into account the qual­i­ty of the burn­er, is mon­i­tored by a con­troller, a spe­cial device that records the flow of fuel into the burn­er.

Flare burn­ers work dif­fer­ent­ly. Here, the pel­lets enter a spe­cial plat­form, where they are blown with air, which results in a pow­er­ful and sta­ble torch. The flame in this case is direct­ed in a hor­i­zon­tal plane. The vol­ume of air sup­plied by the fan is suf­fi­cient for com­plete com­bus­tion of fuel pel­lets. Both the first and sec­ond types of burn­ers cope well with the task of heat­ing the water jack­et of the boil­er.

Processes running in automatic mode. The main advantages of pellet boilers

Com­par­ing sol­id fuel units oper­at­ing on pel­lets with con­ven­tion­al boil­ers, spe­cial atten­tion is drawn to the pres­ence of auto­mat­ed process­es, which not only improve the per­for­mance of boil­er equip­ment. Pel­let boil­ers can be con­sid­ered almost autonomous heat­ing devices. Fac­to­ry mod­els have the fol­low­ing advan­tages:

  • pre­cise­ly cal­cu­lat­ed dosage of fuel for sup­ply to the boil­er fur­nace;
  • auto­mat­ic igni­tion and extin­guish­ing cycle of the burn­er;
  • tech­ni­cal abil­i­ty to adjust the inten­si­ty of com­bus­tion;
  • tech­no­log­i­cal con­trol over the degree of heat exchang­er heat­ing;
  • pres­sure con­trol inside the boil­er equip­ment;
  • auto­mat­ed trac­tion con­trol.

All of these process­es meet the require­ments that apply to almost all heaters used for domes­tic heat­ing sys­tems. The lat­est fac­to­ry prod­ucts are dis­tin­guished not only by high per­for­mance and effi­cien­cy (92%), but also by a high lev­el of safe­ty. You can list the advan­tages of this tech­nique for a long time. The only neg­a­tive of all this is the high price of equip­ment, when com­pared with clas­sic-type boil­ers.

A sol­id fuel boil­er, along with a pel­let burn­er, can be made by hand, with a lit­tle effort, upgrad­ing an exist­ing heat­ing device at home. Alter­ation of sol­id fuel boil­ers for pel­lets will not take much time. It is enough to make changes to the com­bus­tion cham­ber of the unit and pur­chase a spe­cial burn­er. Re-equip­ment will take some time, cost a cer­tain amount, but in the end it will be pos­si­ble to count on good per­for­mance of the heater in a new role.


As a result, hav­ing eval­u­at­ed all the advan­tages and tech­ni­cal capa­bil­i­ties of pel­let boil­er equip­ment, we can draw a very def­i­nite con­clu­sion. This tech­nique is rel­e­vant today and can suc­cess­ful­ly com­pete with gas units. For res­i­dents of areas where there is no cen­tral­ized gas sup­ply sys­tem, pel­let boil­ers are able to solve all the house­hold needs of the inhab­i­tants of the house. High pow­er, high pro­duc­tiv­i­ty and, most impor­tant­ly, the pos­si­bil­i­ty of long-term oper­a­tion with­out human inter­ven­tion make such equip­ment very pop­u­lar.

Hav­ing on hand the cal­cu­la­tion of fuel con­sump­tion, you can achieve long-term oper­a­tion of the heat­ing sys­tem with­out your par­tic­i­pa­tion. For heat­ing a liv­ing area of ​​100 sq. meters (with a ceil­ing height of 2.8–3 m), 100 kW of ther­mal ener­gy is enough, which cor­re­sponds to the com­bus­tion of 25–30 kg. pel­let. Con­se­quent­ly, a lit­tle less than a ton of this fuel will be required per month. Of course, at a cost, such fuel is 5–7 times more expen­sive than nat­ur­al gas, how­ev­er, in its absence, pel­lets are the best alter­na­tive to coal and ordi­nary fire­wood. Which boil­er to choose for instal­la­tion in your own home is up to you.

If you want to have clean­li­ness, warmth and com­fort at home. On top of that, if you want to have more free time, sol­id fuel pel­let boil­ers will be a great find. You don’t have to become a stok­er, you don’t have to run around at night and see that the boil­er does­n’t go out. With such equip­ment, your coun­try house or cot­tage will become much more com­fort­able and cozy.


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