Manure disposal, disposal and burning of chicken manure. Canadian technology for recycling chicken manure
Owners of patent RU 2538566:
The invention relates to the field of energy and can be used in boiler units for the disposal of bird droppings, including directly at poultry farms in order to generate thermal and electrical energy, as well as obtaining ash as a valuable mineral fertilizer. The technical result is the combustion of bird droppings with complete combustion of harmful and foul-smelling gases. The method involves feeding bird droppings into the combustion chamber with organizing the combustion process in its lower layer part and afterburning the generator gas and volatiles in its upper part. In this case, bird droppings are fed into the upper vortex part of the combustion chamber, followed by drying it when moving through this part under the influence of gravity, and then into successively located layers (zones) of the bale of the lower layer part of the combustion chamber: a layer of drying and releasing volatiles, a layer of hot inert coke, reducing layer, oxidative layer of coke burnout, layer of cooling, granulation and ash unloading, mixed by a rustling bar with the supply of heated primary air through the grate on which the above layers are placed, followed by afterburning of the generator gas and volatiles in the upper vortex part of the combustion chamber . 2 n. and 3 salary f-ly, 1 ill.
The present invention relates to the field of energy. A more specific area of application of the invention will be combustion equipment, for example boiler units, including mobile ones, that utilize poultry, for example chicken, droppings directly at poultry farms for the purpose of generating thermal and electrical energy, as well as producing ash as a valuable mineral fertilizer.
The following technical solutions can be selected as analogues of the proposed invention.
A known flare method of burning solid fuel in a dusty state in a chamber gamma furnace with intersecting jets (Kotler V.R. Special fireboxes for power boilers, M.: Energoatomizdat, 1990, p. 18, fig. 8). In such a firebox, high thermal intensity of the combustion volume is ensured, good retention of fuel particles in the combustion volume due to the creation of vortex movement of gases with a horizontal axis of rotation, ensuring high combustion completeness. The disadvantage of this method is the instability of the combustion process when the load fluctuates in fuel consumption and humidity, heat, leading to the formation of harmful NOx oxides, unsuitability for burning coarse-grained high-moisture fuels, which include bird droppings.
There is a known method for burning crushed fuel, described in patent RU 2127399, published on March 10, 1999, in which the temperature in the pre-furnace is maintained at a level not exceeding the softening temperature of the ash. The disadvantage of this method in relation to the problem of burning bird droppings is the impossibility of thermal decomposition of harmful products of gasification of bird droppings due to the relatively low temperature of the combustion process and the lack of the possibility of pre-drying the fuel inside the furnace itself due to the cyclonic combustion principle.
As the closest analogue of the proposed invention, a device for burning a mixture of carbon-containing materials and manure according to patent RU 2375637, published on December 10, 2009, and, accordingly, the method of burning manure described in this source can be selected. The proposed device includes a firebox for burning bird droppings, containing a radiation chamber with blowing nozzles. The method of burning bird droppings in a known device involves feeding bird droppings into a radiation chamber with the organization of the fuel combustion process in its lower layer part and the recovery of generator gas and volatiles in its upper part. The device known from RU 2375637 is intended directly for burning litter and droppings, however, this device will be characterized by all the disadvantages listed above for the method according to patent RU 2127399. That is, thermal decomposition of harmful and smelly products of gasification of bird droppings is also impossible and there is no possibility of pre-drying fuel inside the firebox itself due to the lack of a fuel supply mechanism. In addition, the device according to RU 2375637 is quite complex in design, including a system of partitions between the mass of burned manure and combustion fuel, located in the radiation chamber of the firebox (their low reliability is obvious), and also requires a separate unit for cleaning the flue gases.
In turn, the proposed invention will eliminate the above-mentioned disadvantages and will allow us to propose a method for burning bird droppings, as well as a firebox for implementing the method, which will allow burning bird droppings with complete afterburning of harmful and foul-smelling gases. The specified technical result is achieved by using the proposed method of burning bird droppings, as well as a boiler for implementing the method.
The proposed method of burning bird droppings involves feeding bird droppings into the combustion chamber with the organization of the fuel combustion process in its lower combustion part and the afterburning of generator gas and volatiles in its upper part. Unlike the analogue, bird droppings are fed into the upper vortex part of the combustion chamber with its drying while moving through the mentioned part under the influence of gravity. In the lower layer part of the combustion chamber, a semi-gas generation combustion process is organized in a stirred bale containing a layer of hot inert coke, followed by afterburning of the generator gas and volatiles in the upper vortex part of the combustion chamber. In this case, jets of heated secondary air are blown into the vortex part of the combustion chamber, directed towards each other. Heated primary air is supplied to the lower layer part of the combustion chamber. The said bale is mixed with a rustling bar. Exhaust gases from the combustion chamber enter the radiation chamber.
The proposed boiler for burning bird droppings is a combustion chamber divided into an upper vortex part with at least one window for unloading bird droppings and secondary air blowing nozzles and a lower layer part equipped with means for organizing a semi-gas-generating combustion process in a stirred bale containing a layer of hot inert coke. In the lower layer part of the combustion chamber there is a grate, on which layers of the bale are placed from bottom to top: a zone of cooling, granulation and ash unloading, in which the rustling bar moves; oxidative zone of coke burnout; recovery zone; inert coke zone; drying and volatile release zone. The grate contains primary air blow nozzles. Nozzle nozzles are built into the very top of the combustion chamber, through which secondary air is blown into the boiler, forming a vortex combustion zone. A radiation chamber is connected to the upper vortex part of the combustion chamber. The walls of the combustion chamber and radiation chamber are shielded by pipes of the circulation circuit of the boiler plant.
Bird droppings are a special and specific fuel, making it difficult to burn in traditional combustion devices intended for disposal wood waste and other products of plant origin. The main features of poultry droppings are relatively high initial humidity, relatively high ash content, low temperature melting of ash, which causes an increased tendency to slag formation, high content in fuel gasification products of substances harmful to the environment and smelly to humans: ammonia, hydrogen sulfide, mercaptans, etc.
Accordingly, the technology for burning bird droppings must meet the following basic requirements:
Providing the possibility of preliminary drying of the fuel in the layer to a humidity corresponding to the conditions of the combustion process;
Ensuring the possibility of thermal decomposition in the combustion chamber of harmful and foul-smelling gases, such as ammonia, hydrogen sulfide, mercaptans, in order to avoid their entry into the flue gases into environment;
Elimination of the possibility of slagging of the firebox grate and heat transfer surfaces of the boiler tube bundle;
Ensuring, if possible, the capture of fine particles of ash residue and unburned fuel particles carried away by flue gases before they enter the flues of the heat exchange surfaces of the boiler unit.
Accordingly, the goal when creating a method for burning bird droppings and the corresponding firebox will be
Ensuring the possibility of burning bird droppings subject to solid ash removal;
Elimination of the possibility of slagging of the furnace grate and the tube bundle of the boiler unit;
Neutralization of harmful gases released during the combustion of litter;
Cleaning flue gases from fine ash particles before they reach the heat exchange surfaces of the convective tube bundle of the boiler unit;
Elimination of the possibility of formation of harmful nitrogen oxides NO x ;
Improving the ignition conditions of high-moisture mixed fuels;
Increasing the stability of the combustion process and the completeness of combustion.
To achieve this goal, the boiler is divided by pinching 2 into two chambers: combustion chamber 3 and radiation (convective) chamber 4. Combustion chamber 3 is conventionally divided in height into two parts: the lower layer and the upper vortex. In the lower layer part on the grate in a bale (that is, in a fixed layer of fuel) with a height of at least 300 mm, a semi-gas generation combustion process is implemented, including drying of fresh fuel, the release of volatile components from it with the formation of coke, the formation of generator gas in the reduction zone and the burning of coke in the oxidation zone of the bale. The drying of fresh wet fuel, efficient ignition of fuel and increased combustion stability are facilitated by the presence of a stabilizing ignition layer of hot inert coke in the bale. To maintain the gas-generating combustion process, primary air in an amount of 70% of the theoretically required is supplied to the gas-generating zone from below through channels in the grate.
In the oxidation zone of the bale, the temperature is quite high, which leads to the melting of the outer surface of the ash particles and their softening. However, slagging of the grate does not occur due to the fact that when the ash is lowered by gravity, convective cooling of the ash particles occurs by the flow of primary air supplied from below through the channels of the grate, as well as conductive cooling by removing heat from the softened and melted ash particles to the cooler solid particles in the lower layer of ash, forming a protective layer separating the zone of melted particles from the surface of the grate. Part of the heat released in the oxidation zone is transferred through conductive heat exchange to the upper, colder reduction zone, where the reaction of CO 2 reduction to CO takes place with heat absorption. As a result of cooling, a film of liquid slag crystallizes on the surface of ash particles, which leads to their granulation and transformation into small-sized granules suitable for solid ash removal. Access of cooling air to ash particles and active mixing of melted ash particles with cooler particles of solid ash is ensured by reciprocating movement along the grate of the screwing bar 7. The speed of boring the layer and removing solid ash is such that, according to the thermal balance of the ash layer, removal of excess heat, and also maintained a protective layer of solid ash of sufficient thickness so that the process of cooling and crystallization of melted ash particles occurs in it, in order to protect the grate from slagging and ensure solid ash removal. In addition, cooling of the ash layer is also carried out by removing part of the heat to the screen pipes 9 of the boiler circulation circuit, located on the side surface of the combustion chamber.
In the upper part of the combustion chamber 3, vortex combustion of the resulting generator gas and volatiles is realized, afterburning of small fuel particles removed from the layer and return of ash particles to the layer, partial drying of fresh fuel, as well as thermal neutralization of harmful and foul-smelling gases. To do this, into the vortex zone of the combustion chamber 3 through nozzles 5, located opposite each other in the pinching area 2 and directed downward at an angle of 30...60° to the horizon, sharp jets are blown at a speed of 100...140 m/s heated to 250-350°C secondary air. The amount of secondary air is 45-50% of the total amount of air required for combustion. The direction of movement of the jets is counter-directional due to the fact that the nozzles 5 on the walls of the furnace opposite each other are installed with a certain step in the horizontal plane. The opposing arrangement of nozzles helps to stabilize the combustion source and equalize the temperature field in the vortex zone. Thanks to such aerodynamics, in the above-layer space of the furnace below pinch 2, as a result of the impact interaction of the jets, two large vortices with a horizontal axis of rotation are formed. In the center of the furnace, the trajectories of vortex movement are downward, and near the walls of the furnace, they are upward.
Pinch fireboxes were historically designed as forced semi-fireboxes. open type, having a high thermal stress of the combustion volume. They are usually used to implement liquid slag removal, as they develop a high temperature. However, in this case, due to the screening of the combustion chamber by the pipes of the boiler circulation circuit, excess heat is removed from the combustion zone, which makes it possible to organize the combustion process, ensuring a reduction in the temperature of the combustion volume to a level that eliminates slagging of the furnace and the formation of harmful nitrogen oxides NO x. Due to the supply of sharp blast and swirling flow, active mixing of the generator gas and heated secondary air is carried out, due to which a sufficiently high temperature is maintained in the area of impact of the jets in the center of the furnace, necessary for the thermal neutralization of harmful and foul-smelling gases.
The window for unloading fresh fuel 1 is structurally located so that when unloading the fuel enters the highest temperature zone of the vortex, directed downward to the layer, due to which, in the process of falling into the layer, partial drying of the wet fuel occurs and the removal of small particles with high windage is reduced due to the ejection effect of high-speed jets. By organizing multiple circulation of flue gases in a vortex, small solid particles of fuel, removed from the layer until they are completely burned, are retained in the radiation chamber below the constriction. This ensures an increase in the completeness of fuel combustion and a reduction in heat loss due to mechanical underburning. Due to the intersection in the area of the exit from the nozzles 5 of slow jets of ascending flows, which have low kinetic energy, with high-speed inclined jets from nozzles 5, which have high kinetic energy, small particles of solid ash residue are intercepted from the upward flow and separated into a downward high-speed jet. Due to the acquired kinetic energy, when turning back over the layer of downward vortex jets under the influence of inertial force, ash particles are carried out of the jet and fall into the layer. Thus, flue gases are purified from fine ash particles and are not allowed to be carried into the convective part.
The proposed technology for burning bird droppings is carried out as follows. Bird droppings through the window (feeder) 1 enter the high-temperature part of the vortex zone of the combustion chamber 3, where, in the process of falling onto the layer, it is partially dried. On the grate 6 there is a layer of fuel with a thickness of at least 300 mm (bale), in which the semi-gas generation process is realized. In the bale, as shown, the following are located sequentially from top to bottom: a drying and devolatilization zone, an inert coke zone, a reduction zone in which generator gas is formed, an oxidative zone of coke burnout, a cooling zone, granulation and ash discharge. The bale itself is motionless on the grate, but inside it there is a gravitational lowering of the fuel, which goes through all stages of the process sequentially. The lower part of the bale (zone of cooling, granulation and ash unloading) is subjected to continuous scissoring by means of a scissor bar 7, with the help of which the ash is unloaded into the ash collector 8. To maintain the process in the bale and cool the slag from below, heated to a temperature of 250 is supplied through the holes in the grate 6 -350°C primary air in an amount of 70% of the theoretically required.
Secondary air heated to 250-350°C is blown into the vortex zone of the radiation chamber 3 through counter-inclined nozzles 5 located in the pinching area 2 between the combustion chamber 3 and radiation chamber 4, heated to 250-350°C in an amount of 70% of the required one at a speed of 100...140 m/s . As a result of the counter interaction of the jets, vortices are formed in which active mixing with the generator gas and its combustion occurs, combustion of fine solid particles of fuel removed from the layer, thermal neutralization of harmful and foul-smelling gases released from bird droppings. As a result of the transverse interaction of jets with different kinetic energies, when they intersect each other from the flow of rising flue gases, solid particles of the ash residue are separated and returned to the layer. To prevent the creation of too high temperatures in the combustion chamber, creating a threat of ash melting and slagging of the firebox, side surfaces the combustion chamber is shielded by pipes 9 included in the circulation circuit of the boiler, to which heat is removed.
As was shown above, the device for implementing the proposed method is a furnace divided by pinching 2 into two chambers: combustion chamber 3 and radiation chamber 4. Furnace chamber 3, in turn, is divided into two zones: layer combustion and vortex combustion. On the grate 6 there is a stationary pile of fuel with a height of at least 300 mm, in which all stages of the gas-generating process are implemented. To maintain it, heated primary air is supplied through the holes in the grate 6. The lower part of the layer is subjected to continuous scissoring through the reciprocating movement of the scissor strip 7, which removes ash into the ash collector 8. In the vortex combustion zone in the pinch area 2, blow nozzles 5 are located counter-obliquely in a horizontal plane relative to each other to supply heated secondary air. The window for unloading fresh fuel into the furnace is located so that fresh fuel is unloaded along the line of intersection of the axes of oncoming jets in order to ensure a downward movement of the fuel down into the layer along with the jets. Due to the ejection effect of the jets, this reduces the removal of fine particles of fuel with high windage, and the high temperature in the combustion center at the point of collision of the jets ensures partial drying of the wet fuel even as it falls into the layer. When the jets cross transversely in the area of the nozzle mouth, the high-energy jet separates solid particles of the ash residue from the ascending jets of flue gases with lower energy and returns these particles to the layer.
Thus, it is proposed effective method for burning bird droppings, as well as a firebox for its implementation, which will allow burning bird droppings with complete combustion of harmful and foul-smelling gases.
1. A method of burning bird droppings, which involves feeding bird droppings into the combustion chamber
with the organization of the combustion process in its lower layer part and the afterburning of generator gas and volatiles in its upper part, characterized in that
bird droppings are served
into the upper vortex part of the combustion chamber with its subsequent drying when moving through this part under the influence of gravity,
and then into successively located layers (zones) of the bale of the lower layer part of the combustion chamber:
layer of drying and release of volatiles,
layer of hot inert coke,
restoration layer,
oxidative layer of coke burnout,
a layer of cooling, granulation and ash unloading, mixed by a rustling bar with the supply of heated primary air through the grate on which the above layers are placed,
followed by afterburning of the generator gas and volatiles in the upper vortex part of the combustion chamber.
2. The method according to claim 1, characterized in that jets of heated secondary air directed towards each other are blown into the upper vortex part of the combustion chamber.
3. The method according to claim 1, characterized in that the exhaust gases from the combustion chamber are supplied to the radiation chamber.
4. A boiler for burning bird droppings, containing a combustion chamber with blowing nozzles, characterized in that
the combustion chamber is divided into
an upper vortex part with at least one window for unloading bird droppings and secondary air blow nozzles, and
the lower layer part for organizing the process of burning bird droppings in accordance with any of paragraphs 1-3.
5. The boiler according to claim 1, characterized in that the walls of the combustion and radiation chambers are shielded by pipes of the circulation circuit of the boiler installation.
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The most common technology for the production of broiler meat in Ukraine involves raising chickens on the floor on deep, permanent litter. The main advantages of this technology are the use of relatively simple and cheap equipment, a high level of mechanization technological processes, simplicity and low labor intensity of work on poultry care and poultry house sanitation, fewer carcass defects, increased categorization compared to cage rearing. The main disadvantage is the need for a significant amount of scarce bedding materials. Per 1 broiler raised, it is necessary to spend 1-1.5 kg of litter, depending on the season and growing period. After 5-7 weeks of growing chickens, litter is added to the litter. As a result, for each broiler raised we get about 3-5 kg of litter litter (LM) with a moisture content of 15 to 50%. If we assume that about 500 million broiler chickens are raised in Ukraine per year, the yield of broiler litter alone will be at least 2 million tons. If we add here the PP obtained by keeping other species and production groups of poultry, its total yield can be estimated at no less than 3 million tons.
PP disposal causes a lot of trouble for poultry farms. Large plots of land are needed for its storage and processing. PP contains a significant amount of substances harmful to the environment, weed seeds, and often eggs and larvae of helminths, pathogenic microorganisms. He is also favorable environment for the development of flies, rodents, helminths and microorganisms and, under improper conditions of storage, processing and use, serves as a source of pollution of surface and groundwater, soil and atmosphere with harmful substances, poses an epizootic and sanitary-epidemiological threat to poultry farms themselves, surrounding areas and the environment generally.
According to the state waste classifier, droppings are classified as Group III hazardous substances. Agricultural enterprises, peasant and other farms engaged in the production, processing and marketing of livestock and poultry products, and at the same time disposing of waste (manure and bird droppings), are payers of environmental tax. The cost of their placement at open landfills averages 100 UAH/t. Due to problems with litter disposal, poultry farms have constant conflicts with local environmental and sanitary services. Therefore, taking into account the above, every poultry farm faces a problem: what to do with bird droppings?
The traditional way of using PP is to process it into organic fertilizers, since it contains a significant amount nutrients for plants (nitrogen, phosphorus, potassium, calcium, microelements) (Table 1). In the USA and some European countries, processed manure is also used as a feed ingredient for ruminant animals, because it also contains a significant amount of fiber, protein, individual amino acids, lipids, and nitrogen-free extractives. Table 1. Chemical composition litter litter after raising broiler chickens,% (according to the company "SV Technologies")
| The name of indicators | Meaning of indicators |
| Moisture contents, % | |
| Dry matter content, % | |
| Nitrogen, % | |
| Calcium,% | |
| Phosphorus, % | |
| Crude lipids, % | |
| Crude fiber, % | |
| Nitrogen-free extractives, % | |
| Lysine, % | |
| Histidine, % | |
| Arginine, % | |
| Aspartic acid,% | |
| Threonine, % | |
| Glutamic acid,% | |
| Proline, % | |
| Glycine, % | |
| Alanine, % | |
| Valine, % | |
| Isoleucine and leucine, % | |
| Tyrosine, % | |
| Phenylalanine, % | |
| Copper, mg/kg | |
| Zinc, mg/kg | |
| Iron, mg/kg | |
| Manganese, mg/kg | |
| Cobalt, mg/kg | |
| Magnesium, mg/kg | |
Methods for processing PP into organic fertilizers or feed additives must ensure the neutralization of pathogenic microflora, weed seeds, helminth eggs and larvae, stabilization of nutrients, and deodorization of the final product, and this requires considerable costs. By the way, the high costs of manure disposal and payments for environmental pollution became one of the reasons for the cessation of activity of a number of broiler poultry farms in Western Europe. In addition, a significant number of poultry enterprises in Ukraine do not have enough agricultural land to use the entire volume of manure produced as organic fertilizer on their own fields. Selling litter in any form to other enterprises is associated with significant difficulties and costs. In this regard, in Lately increasingly, as an alternative to processing manure into organic fertilizers, they offer the combustion of litter and non-litter manure in one way or another in order to produce thermal and electrical energy. Both options have their supporters and opponents. Let's consider the arguments of both.
Production of organic or organo-mineral fertilizers based on litter manure.
Arguments for:
a) obtaining a product valuable for crop production in the form of organic or organomineral fertilizers with a high content of nitrogen, phosphorus and potassium, correct use which helps to improve the structure and microflora of soils, enrich them with humus, increase agricultural yields by 10−30%;
b) improvement of the environment as a result of neutralization of pathogenic microflora, weed seeds, eggs and larvae of weeds, deodorization of unpleasant-smelling substances;
c) the possibility of organization closed loop disposal of litter in vertically integrated agro-industrial associations.
Arguments against:
a) a significant amount of nitrogen (up to 50%) and other nutrients are lost during storage, processing and use as fertilizer;
A) long duration processing cycle, due to which the above-mentioned negative factors operate for a considerable time;
b) a complex of mechanized means is required, significant labor and energy costs are required for the storage and processing of raw materials, storage, transportation and use of the resulting fertilizers;
c) the need for significant land areas for storage, processing and use of the resulting fertilizers. The maximum dose of organic fertilizers based on bird droppings: compost - 60 t/ha, dry bird droppings - 8 t/ha;
d) in case of improper processing, introducing excessive doses of manure, land degradation occurs, accumulation of nitrates and nitrites in agricultural crops, contamination of land with weed seeds, and pollution of the environment with harmful substances and unpleasant odors.
Using litter droppings for energy.
Arguments for:
a) the simplest and least labor-intensive and energy-consuming solution to the problem of litter disposal;
b) rapid and reliable neutralization of all harmful factors and improvement of the environment; c) obtaining heat or electricity, which are increasing in price every year;
d) the possibility of meeting one’s own needs for thermal and electrical energy by burning manure;
e) ash from burning manure can be stored for years without loss of nutrients, used as a mineral fertilizer containing potassium, phosphorus, calcium and a number of other elements (Table 2) at optimal agrotechnical periods;
f) short production cycle, therefore, the negative factors mentioned above act for a short time;
e) reduction of transport costs by 5−6 times;
g) large plots of land are not needed for storing and processing litter.
Arguments against:
a) loss of nitrogen from raw materials in the technological cycle;
b) the fairly high cost of equipment for burning manure (at the same time, it is not more than, for example, for processing manure in biogas plants);
G) possible problems with the sale of the resulting heat, electricity and ash.
Table 2. Chemical composition of ash after burning broiler litter (according to SV Technologies company)
| Name of substance | Content,% |
|
rest |
Analyzing the pros and cons of each option, we can come to the conclusion that the energy processing of PP can be quite competitive with the option of processing it into organic fertilizers, at least in poultry enterprises that do not have a sufficient amount of their own agricultural land.
Several possible options for the energy use of PP by combustion are now proposed:
1) direct combustion in boiler plants to obtain hot water, steam or electricity;
2) gasification (pyrolysis) of manure for the same purpose;
3) production of fuel granules (pellets) or briquettes from PP, then the granules or briquettes can be burned on site to produce hot water, steam or electricity, or sold for use as fertilizer or as fuel.
Processing of PP by direct combustion
Direct combustion of PP does not require its granulation or drying. The heat of combustion of PP is in the range of 2600-3400 kcal/kg (10300-14250 MJ/kg). The content of harmful substances in combustion products emitted into the atmosphere when using modern combustion devices does not exceed maximum permissible concentrations (MPC). Burning 1 ton of PP allows you to obtain up to 2 Gcal of heat in the form of hot water or 3 tons of steam for technological needs. This saves up to 270 m3 of natural gas or up to 240 kg of liquid fuel. Coefficient useful action boiler units with direct combustion of manure is 60−85%. The ash yield is 10−18% of the initial amount of PP. Ash can be applied to various agricultural crops without additional processing in the amount of 2−10 c/ha. The use of this ash as a fertilizer helps increase crop yields by 10−15%.
Features of PP as a fuel are high humidity, ash content, and the presence of a significant amount of alkali and alkaline earth metals in the ash, which causes its high slag-forming ability. In this regard, until recently it was not always possible to achieve stable and reliable combustion of PP in a boiler unit. This problem has now been solved by using high-temperature circulating fluidized bed combustion technology, which ensures reliable combustion of material with a moisture content of up to 60%.
A PP combustion workshop usually includes: a boiler room, a raw material warehouse and a storage facility for ash from PP combustion. You don’t have to build an ash storage facility, but immediately pack the ash into bags (big bags) or transport it to the place of use in a closed transport.
The standard range of direct combustion workshops for PP was designed by the Agro-3 Ecology group of companies (Moscow). According to this group of companies, for a boiler house that burns, for example, 75 tons of PP per day, with a thermal power of 5 Gcal/hour. (Up to 7 tons of steam per hour), a room made of prefabricated reinforced concrete or metal structures and sandwich panels with dimensions of 18x15 m and a height of 13 m is required.
A raw material warehouse for uninterrupted supply of a boiler room of the specified capacity can be located in an unheated room with an area of about 300 m2 (18x18 m) with a height of 6 m.
It can also be made from metal structures and sandwich panels. The ash storage can be located in an unheated room with an area of approximately 140 m2 (12x12) with a height of 6 m.
A grain level sensor can be used to monitor fuel consumption or ash level. The workshop maintenance staff is 3-4 workers per shift, the electrical power consumption is about 100 kW.
The capital costs of creating a workshop for burning PP to produce hot water and steam depend on the thermal power and the amount of PP burned (Table 3).
Table 3. The required amount of capital costs for creating a workshop for direct combustion of PP to produce hot water and steam
|
The name of indicators |
Amount of burned PP |
|||
| 1 | Heat production, Gcal/year. | |||
| 2 | Steam production, t/year. | |||
| 3 | ||||
| including: | ||||
| 3.1 | Design work | |||
| 3.2 | Equipment | |||
| 3.3 | Installation | |||
| 3.4 | Commissioning works | |||
| 3.5 | Construction and installation work (boiler room, PP and ash storage, etc.) * | |||
* - Without the cost of excavation, concrete, survey work and approvals.
The economic efficiency of a workshop for burning PP only to produce thermal energy can be approximately calculated based on the replacement of natural gas with litter manure (4.7 UAH/m3) in a boiler room designed to produce a similar amount of heat, and phosphorus and potassium fertilizers (2.0 UAH ./kg) ash from burning PP (Table 4).
Table 4. Economic effect and payback period for capital investments in a manure burning workshop.
|
The name of indicators |
Amount of PP burned per day, tons |
||
| Capital costs, UAH million. | |||
| Amount of litter burned per year, thousand tons | |||
| Net heating capacity of the boiler room (based on heat output) Gcal/hour. | |||
| Amount of gas that is replaced per year, m3 | |||
| The calorific value of the gas that is replaced by river, thousand. m 3 | |||
| Cost of replaced gas, UAH million. | |||
| Amount of ash received per year, t | |||
| Cost of substituted mineral fertilizers, million UAH. | |||
| Total cost of products received (heat + ash), million... UAH. | |||
| Annual operating costs *, million UAH. | |||
| Total annual economic effect, UAH million. | |||
| Payback period of investments, months | |||
* - Operating costs include the cost of electricity, reagents for chemical water treatment, personnel costs and transportation costs.
The resulting thermal energy can be used to provide heat, primarily for the needs of the poultry farm itself, as well as nearby settlements. However, in practice this is not always possible. In this case, it is recommended to use the resulting thermal energy to generate electricity. So, with a production of 7 t/hour. steam with parameters of 1.4 MPa and 250 ºС, heating network water to 80 ºС, you can also produce approximately 630 kW hour every hour. electricity, of which 100 kW hour. - will be spent on the boiler house’s own needs, the rest - on the needs of the poultry farm or for sales. The unit cost of a steam turbine unit is 8200 UAH. / KW, total capital costs will increase by another 5.2 million UAH. The annual economic effect from the sale of ash and electricity alone will amount to UAH 9.4 million. The payback period for capital costs is 2.5 years.
Currently, work on the design of direct burning of manure shops, the supply of equipment for them and a number of other works is carried out by a number of institutions: the ATT group of companies (Alternative Heat and Technologies in Kharkov), the Kovrov Furnace and Boiler Equipment Plant (Kovrov, Russia), already mentioned group of companies AGRO-3 "Ecology" (Moscow), SPC "ERKO" (Moscow), LLC "Abono Group" and others.
Gasification (pyrolysis) of litter manure.
Gasification (pyrolysis) is the thermal decomposition organic matter with a lack of oxygen. Gasification or pyrolysis of manure, both litter and non-litter, is considered promising direction its energy use, which, according to some experts, has a number of advantages compared to the processing of manure in biogas plants, in particular:
Higher efficiency of converting biomass into useful energy (in biogas plants no more than 50%, in pyrolysis plants up to 85%);
All-season, since the efficiency of generator gas production is practically independent of external conditions;
Compactness, less metal consumption of the equipment used;
Lower transportation costs at all stages of the waste disposal process;
Possibility of converting manure containing lignin containing additives (shavings, straw, etc.) into gas and electricity;
Waste-free recycling process;
Possibility of almost complete automation of the processing process, low operating costs;
The versatility of the equipment used, the possibility of its use for burning any type of biomass;
High environmental friendliness of the technology used.
As a result of pyrolysis of manure at a temperature of 300−800 ºС, a vapor-gas mixture is obtained, which consists of a mixture of flammable gases (the so-called generator or pyrolysis gas), a coal-like solid residue (charcoal) and ash. Producer gas is used to maintain the operation of the pyrolysis plant itself, to obtain thermal energy for household needs, to replace natural or liquefied gas in various devices, to produce electricity, and after appropriate preparation, as fuel in internal combustion engines. The coal-like residue is also used as fuel in the pyrolysis plant itself or for the production of fuel briquettes. Ash is used as fertilizer in the metallurgical and construction industries.
The average calorific value of generator gas is 1200 kcal/m3 (5030 kJ/m3). Its average component composition is given in Table 5. After appropriate processing, it is possible to obtain generator gas with a high content of flammable gases.
Table 5. Component composition of generator gas from PP gasification
|
Component name |
|
| Carbon monoxide (CO) | |
| Hydrogen (H2) | |
| Methane (CH 4) | |
| Nitrogen (N 2) | |
| Other gases |
The gasification process has a total efficiency of up to 80%. From 1 kg of PP in terms of dry matter, an average of 2 m3 of total generator gas is obtained calorific value 2400 kcal.
Pyrolysis boilers, including household ones, in which PP can also be burned, are now produced by many manufacturers, including in Ukraine (Motor Sich, etc.). To leading manufacturers industrial equipment for the gasification of various organic wastes, in particular manure, belong to the already mentioned company LLC Abono Group, LLC TsentrInvestProekt (Moscow), Flex Technogies (UK), and Planitec srl (Italy). The latter supplies mini-CHP in the power range from 60 kW to 1 MW.
The preparation of manure in the installations of this company for subsequent gasification involves:
Drying the raw materials until relative humidity 12−15 %;
Removal of foreign metal impurities;
Grinding manure to particles no larger than 3 cm;
Dosed addition of limestone to neutralize acids formed during gasification.
To dry the litter, reversible heat is used, which is generated when the generator gas is removed and the heat removed from the cooling system of the gas turbine engine.
The performance indicators of a mini-CHP designed to process PP from one poultry house for 50 thousand laying hens or broilers are shown in Table 6. The cost of mini-CHP equipment is about 200 thousand euros.
Table 6. Performance indicators of mini-CHP with a capacity of 900 tons of PP per year
|
The name of indicators |
Meaning of indicators |
| CHP operating hours per day, hour. 2 | |
| CHP operating hours per year, hours. 8000 | |
| Total amount of litter processed per year, tons | |
| Amount of litter processed per day, tons | |
| Average moisture content of litter, % | |
| Electrical energy produced per hour, kW - h. | |
| Thermal power for external consumers, kW (Gcal x hour) | |
| Thermal power consumed for own needs, kW (drying manure, maintaining the operation of the gas generator), kW (Gcal x hour). | |
| Ash output per year, tons |
The equipment of a mini-CHP allows for the production of 0.8 kW of electrical energy from 1 kg of PP with an efficiency of 27%, the production of thermal energy for a heating system in the form of hot water with an efficiency of 45%, and compliance of gaseous emissions into the atmosphere with the current requirements of environmental legislation.
The main disadvantages of pyrolysis boiler units compared to direct combustion units are the price of the equipment is 1.5−2 times higher, and operation is somewhat more complicated.
Using PP to produce fuel pellets or briquettes.
As already mentioned, using the heat and electricity generated by burning manure on site is not always possible. It is possible to sell electricity, but it is difficult and expensive to connect to the public power grid. In this case, it is advisable to use such an option for the energy use of manure as making fuel pellets or briquettes from it. The most suitable for these purposes is PP with a moisture content of no more than 30%. The technological line for the production of granules of the company "Planitec srl" already mentioned above provides for grinding of PP, drying to a moisture content of 15-18%, granulation or briquetting, cooling and packaging, purification of steam and gas emissions. The cost of a drying and granulating installation for 2 tons of granules per hour is about 3.7 million UAH. The resulting granules can be used in solid fuel boilers of any type, including domestic ones, and also as a fertilizer. They can be stored long time without losing yours beneficial properties. The characteristics of manure pellets compared to other types of fuel are given in Table 7.
Table 7. Comparative characteristics of fuel types
| Type of fuel | Heat of combustion, MJ\kg | Sulfur content,% | Ash content,% | Price for 1 kg | Cost of heat received, UAH/GJ |
| Coal | |||||
| PP granules | |||||
| Natural gas * | |||||
| Wood pellets | |||||
| Straw pellets |
* - Per 1 m3.
According to Russian manufacturers, the payback period for equipment for the production of pellets is about 4 years, but in Ukraine, due to high prices for natural gas and other types of fuel compared to Russian ones, according to our calculations it should not exceed 2-2.5 years.
Growing in hydroponics means minimal costs, purity and the availability of almost any complete and environmentally friendly vegetables all year round. Control the quality of what gives you energy and health.
1. Processing litter manure to produce energy can be considered as an economically viable alternative to processing it into organic fertilizers in poultry enterprises that do not have sufficient amounts of their own agricultural land.
2. It is advisable to use direct combustion of litter manure to produce heat or electricity in poultry farms, which can ensure their rational use or sale. 3. Gasification (pyrolysis) of litter manure is recommended to be used whenever possible integrated use or sales of all products received.
4. Processing litter manure into fuel pellets or briquettes allows you to expand markets for products and the possibilities of their use (direct combustion, pyrolysis, as fertilizers).
Melnik V.A., Institute of Poultry Science, NAAS
There is a saying that a man is made of a gentleman like a bullet is made of dung. But these domestic Kulibins folk wisdom slightly adjusted. Now Joint-Stock Company"Belkotlomash" became the first Belarusian enterprise to launch a new promising type of product: water heating boilers, burning litter and dung mass.
Such disposal of poultry waste allows solving two important problems for the industry at once: economic and environmental. The boiler not only produces thermal energy, but also burns chicken droppings, which becomes dangerous if stored, processed and disposed of inappropriately.
It is known that today broiler chickens are raised mainly on deep litter. The advantage of this technology is that From one day of age until slaughter, birds are kept in the same room. Deep litter absorbs moisture and harmful gases well, improves the sanitary condition of the room and serves as thermal insulation. However, this method has one serious drawback, since one chicken requires about 2.5-3 kilograms of sawdust.
As a result, in every factory that uses floor growing technology, tens of tons of used litter and manure accumulate every day. A poultry farm for 400 thousand laying hens receives about 30 thousand tons of litter. When it rots, about 700 tons of biogas are released, including 450 tons of methane, 208 tons of carbon dioxide, 35 tons of hydrogen, hydrogen sulfide and ammonia. Damage to the ecosystem from emissions is estimated at millions of dollars.
Therefore, for poultry farms in Belarus and other countries of the world, recycling poultry waste is a rather difficult task. This manure mass (in natural or granular form) can be used as fertilizer, but it must be applied to the soil in small quantities, since otherwise the land will be taken out of circulation for a long time. If there are several large poultry farms in close proximity to each other, then waste disposal is already a serious environmental problem.
Small water heating boilers are installed directly on the territory of the poultry farm
The best way out of the situation is burning manure in boilers operating on solid fuel. This task is not easy. The litter mass contains sulfur and phosphorus compounds, which destroy the pipe system of the units and render it inoperable in a matter of months. One of the enterprises not only in Belarus, but throughout the entire post-Soviet space that has undertaken to solve this problem is Belkotlomash.
The installation he developed can use litter litter humidity up to 60%. The thermal energy obtained from combustion is used for heating and technological needs of the poultry farm. The litter does not require pre-drying or granulation, which greatly simplifies the entire process. Already today, experts have calculated that the use of such boiler equipment will allow domestic broiler poultry farms to gain a number of competitive advantages. First of all, this will significantly reduce the cost of purchasing gas, which amounts to hundreds of thousands of dollars annually (for poultry farms that use gas boilers), reduce capital costs for the construction of manure storage facilities, and also significantly reduce the environmental load on the environment by disposing of a toxic product without the need for long-term storage. The developers of the new equipment report that The boiler test was successful, therefore, in the very near future it will be supplied to poultry farms in Belarus, Russia and other interested countries in the region.
Poultry farm droppings are a by-product of poultry farming, which is several times larger in volume than the output of finished products: for 1 ton of broiler meat, up to 3 tons of turkey meat are produced - up to 4 tons of droppings: Russian poultry farms produce more than 17 million tons of droppings per year. The prevailing point of view is still that it is a dangerous waste that reduces the profitability of production. This encourages poultry farmers to get rid of it in the cheapest possible way - by taking it to landfills. Pyrolysis and biogas production as methods of manure disposal are not widely used for a number of reasons. The production of pyrolysis gas from litter manure is technologically ineffective, because the original litter is a higher calorie fuel than pyrolysis gas. A biogas plant is a high-tech production that has a number of significant limitations (the temperature at which biogas is released must not exceed established framework: in mesophilic mode: 35±1.0; in thermophilic mode: 55±0.5ºС). After the completion of the biogas release process, 4-5 times more liquid waste requiring disposal remains than the original litter. All the produced biogas is not enough to dry them. Therefore, biogas production is not essentially a method of biowaste disposal.
Video: Burning litter manure in a steam boiler
AGK ECOLOGY LLC offers direct combustion of bird droppings in specialized hot water and steam boilers. In this case, the rate of thermal utilization of one portion of litter is 10-15 seconds. At proper organization combustion process, the concentration of emissions is less than when burning fuel oil, and the resulting ash (up to 14% of the original volume of waste) is an effective potassium-phosphorus fertilizer. Thus, the process of burning manure is characterized by the absence secondary waste, which makes the technology environmentally flawless.
According to the technology we offer, litter is a secondary raw material and a source of additional income. Poultry manure is a raw material for the production of:
- energy resources (heat, steam, electricity) when burned in the form of biofuel with the by-product of mineral fertilizers from the ash.
- organic fertilizers;
B b O To a greater extent, the thermal disposal process is applicable to litter manure, which does not require any preparation before burning. We offer technology for thermal disposal of litter with the production from 1 ton of this waste up to 2 Gcal of heat (DHW, heating), or 3 tons of steam, or up to 600 kWh of electricity, replacing up to 270 m 3 of gas. Additionally, up to 140 kg of ash is obtained - an effective mineral fertilizer. The technology of flare-layer burning of manure is protected by Patent No. 151541 (MKP F23G 7/00).
Specific capital costs for hot water boilers is 10-12 thousand €/t of litter per day, and the payback period does not exceed 2 years only by reducing (or stopping) gas consumption (1 € = 75 rubles).
Below you can watch a detailed video about the process of effective disposal of litter using our equipment.
Specific capital costs for steam boiler houses range from 20 to 17 thousand €/t of manure per day, the cost of heat is about 400 rubles/Gcal. In the case of combined production of electricity and heat, capital costs increase to 36–25 thousand €/t of manure or 2000–1300 €/kW of installed capacity, decreasing with increasing CHP capacity. The cost of electricity ranges from 2.4 to 0.7 rubles/kWh. The payback period for investments ranges from 2 (hot water boilers) to 5 years (mini-CHP with combined production of electricity, steam, heat and fertilizers).
Disposal of caged litter is complicated by its high (70-75%) humidity, and requires its preliminary drying (including due to the heat of combustion products of part of the already dried litter). When it is constantly burned in boilers, drying to a humidity of 30% is sufficient. If long-term storage is necessary, the litter should be dried to a moisture content of no more than 15%. In this case, it can also be used as an organic fertilizer. When drying cell droppings, it is necessary to clean the gases after the dryers not only from fly ash carryover, but also from foul-smelling gases. Absorbers such as wet scrubbers with circulating alkaline water are usually used for this purpose.
Video: Burning cell droppings
But that's not all. Litter disposal by burning it, it leads to the formation of ash, which is a valuable potassium-phosphorus mineral fertilizer that increases crop yields by 10-15%. The volume of resulting ash will be 7-10 times less than the volume of the original litter. Depending on the requirements of the technical specifications, ash can be packed in bags (big bags) or transported to the place of use in bulk form in a closed transport.
Schematic diagram of a steam boiler room
The efficiency of using cellular manure as biofuel increases by minimizing its initial humidity: reducing it from 75 to 65% increases useful heat 5 times: from 0.1 to 0.5 Gcal/t of manure by reducing fuel consumption for drying.
AGK ECOLOGY LLC offers to pre-dry the manure using the heat of the air removed from the poultry houses. The recovery of this heat allows reducing the humidity of the litter to 55-60%. The useful heat output in this case increases to 0.7 Gcal/t of litter, which allows the production of sufficient a large number of heat or saturated steam for production needs, while saving natural gas.
Specific capital costs for the creation of such an energy complex amount to up to 700 thousand rubles / ton of litter per day, and their payback period does not exceed 5-6 years. The cost of thermal energy is 700 rubles/Gcal, steam – 500 rubles/t. A by-product in this case is the formation of 50-60 kg of ash (per 1 ton of raw litter). The production of soil conditioner from this ash increases crop yields by 30-40%, which can significantly reduce the cost of feed and, accordingly, the final poultry product.
Thermal technology is also applicable for
- Disposal of chicken manure
- Burning chicken manure
- Processing of cattle and pig manure
- Litter processing
- Poultry manure processing
