Grain burning
As grain combustion refers to the use of corn as a fuel for the purpose of generating energy.
Distinguishing between the combustion of so-called Ausputz- or minority limited and Verwurfgetreides than or not as food or feed crops and usable burning for this purpose as an energy crop grown grain. While the former is permitted as a standard fuel in certain areas of application with the amended ordinance on small and medium-sized combustion systems (1st BImSchV) coming into force in 01/2010 , the latter is currently not practiced in Germany.
Due to legal and technical problems as well as ethical concerns, grain burning is currently only practiced to a limited extent in German-speaking countries.
background
In the mid-1990s, world market prices for grain were around € 60 to € 80 per ton, and thus in some cases below production costs in Europe. At the same time, oil and natural gas prices were so high that producing grain for incineration proved more economical than using it as food. In this situation, some farmers started to burn grain in pellet heating systems .
The following formula was given as an example (in 2005):
“Selling to flour mills only makes a profit of one cent per kilogram of grain. [...] At a heating oil price of 45 cents per liter of heating oil, the equivalent grain price - 2.5 kilograms of grain replacing one liter of heating oil - would be 18 cents per kilogram, the proceeds at 9 cents per kilogram. "
A cultivation of grain for purely energetic use, which was also initially envisaged, could not establish itself, however, currently all uses are aimed at the combustion of the so-called grain plaster. The decisive factor here were the increasing grain prices on the world market, which in turn made combustion uneconomical, but also ethical concerns.
The main advantage of grain as a fuel over many other biogenic fuels is the infrastructure that is already in place for its production and processing. The existing knowledge about its cultivation and the variety of species and varieties, which are adapted to the most diverse soil and climatic requirements, are advantageous compared to numerous plants that have not been developed as useful plants. [Source?]
Compared to wood, the most widely used biogenic fuel, the small storage space required and the high bulk density with a high calorific value are particularly advantageous. Corresponding systems can be dimensioned small and still be operated effectively.
A pilot project for the use of grain as heating fuel for living space started in early 2007 in an apartment building complex of 24 apartments in the Frankfurt Riederwald estate. For the first time, grain is being used outside of the agricultural sector as a heating fuel.
technical basics
The use of grain as fuel in large plants (e.g. thermal power stations, waste incineration plants ) or for feeding into the power grid is not profitable for farmers as producers. Therefore, the development is currently focused on decentralized systems between 15 and 100 kW, so-called small combustion systems, which contribute to the supply of the farms.
Firing techniques
The combustion of grain requires special systems because grain differs from conventional bioenergy sources such as wood. Either conventional incineration plants are used, which are designed for wood or similar fuels, or new types of plants adapted to the fuel grain. High combustion temperatures are required to burn grain as completely as possible. However, this leads to the ash sintering and forming slag due to its low melting point . Slagging can be countered by adding calcareous aggregates , which increase the ash melting point, but also increase the amount of ash that arises (with 0.5 to 2 percent by weight of lime in the fuel by up to 60% more ash). Another possibility is the combination of grain with other fuels, such as wood chips . This also enables combustion in conventional plants, which are otherwise technically unsuitable for a complete charging with grain.
All systems convey the material to be fired into the combustion chamber by means of screw conveyors or suction lines , which guarantees a continuous supply of fuel and a constant combustion process. Mostly be cooled stoker and Muldenfeuerungen used, but also grate firing (with moving grate). Buffer storage tanks are often used that allow the heat to be used later. In some federal states they are mandatory. Due to the relatively high incidence of ash and slag, regular removal of fuel residues is necessary. This takes place partly automatically.
Possible fuels
All common grains can be used for incineration. Spelzgetreide as barley and oats are characterized by the combustion by relatively high ash melting point (~ 1200 ° C) compared with nude cereals such as wheat and triticale (~ 700 ° C / 800 ° C), which slagging significantly reduced, but at the same time falls more ash on.
Environmental aspects
- (see also article bioenergy )
As with all biogenic fuels , the CO 2 cycle is closed in grain , which minimizes greenhouse gas emissions . The use in decentralized combustion systems also avoids the high transport costs of large centralized systems. The use of inferior, non-marketable grain qualities as fuel appears to be a sensible alternative to other disposal options.
Compared to the use of other fuels such as heating oil or wood, the emissions from the combustion process are sometimes several times higher. In particular, dust , carbon monoxide (CO) and nitrogen oxides as well as chlorine and sulfur compounds pollute the exhaust air. The dust emissions can mainly be reduced by additional dust separators , filters and dedusting devices for the fuel and flue gas. The optimization of the combustion technology (staged combustion and mixing of the gas flow in the afterburning chamber) significantly reduces the NO x and CO emissions, so that the limit values of the immission law are complied with with appropriate technical optimization. Practical technical solutions for reducing emissions of the pollutants chlorine and sulfur not regulated by the 1st BImschV are still pending for small combustion systems.
In the - currently not practiced - production of cereals specifically for incineration, nitrogen oxide emissions could be reduced by reducing the nitrogen content in the cereal grain through reduced fertilization or breeding of low-protein grains. The federal states of Bavaria, Thuringia and Saxony have included corresponding restrictions on the issuing of special permits in the catalog of requirements. In Bavaria and Thuringia, for example, no fertilizer containing chloride may have been applied for a year before grain was grown for incineration. In Saxony, limit values for the nitrogen content in the kiln must be complied with.
Legal situation
Germany
In Germany, the use of grain as fuel in plants with a thermal input of 100 kW or more is subject to approval. The 4th BImSchV and the technical instructions for keeping the air clean (TA Luft) are decisive . Grain heating systems with an output of less than 100 kW - such as heating systems for individual apartments and smaller apartment buildings - are regulated by the 1st BImSchV ( ordinance on small and medium-sized combustion systems ). The Federal Cabinet and the Bundestag finally adopted the new version of the 1st BImschV on December 3, 2009. It comes into force after a 7-week transition period. So far, grain has not been approved as a so-called standard fuel for this size of plant . Individual federal states issued special permits. With the amended 1st BImSchV, grain that is not suitable for use as food is included in the catalog of standard fuels and is therefore also permitted in small systems in future. Accordingly, "cereals not intended as food, such as grains and broken grains, whole grain plants, grain plaster, grain husks and grain stalks and pellets made from the aforementioned fuels" may be used. The use is restricted to automatically charged systems that are approved for this fuel. In addition, only farms and related industries are allowed to practice grain burning.
The same values apply to the emissions from grain combustion systems as to the use of firewood , namely 0.10 g dust / m³ and 1.0 g CO / m³ for systems built by 2014. From 2015, the limit values will be 0.02 g dust / m³ and 0.4 g CO / m³.
Austria
In Austria, too, grain was previously not an approved fuel. The legislation is based on an agreement between the federal government and the states in the sense of Art 15a B-VG with the state legislators, the operation of grain combustion systems is regulated in the state-specific building technology regulations. The approval of such systems is usually tied to evidence of compliance with emission limits and efficiencies. This can cause problems, as the corresponding limit values are based on automatic wood firing systems that, for. B. have significantly lower nitrogen oxide emissions. Only in Styria can other fuels be approved by ordinance, the respective limit values are based on the “local conditions and the nature of the fuels used”.
An upcoming legal reform should change the current situation. She would define cereal grains as "other standardized biogenic fuel". The Austrian standardization institute "Energiekorn" already standardized in advance on October 1st, 2006 in the pre-standard ÖNORM M 7139 and thus defined the precise requirements for grain as fuel.
Economic aspects
While low grain and waste grain are extremely cheap fuels due to their worthlessness as food, the generation of energy using food-grade grain is only competitive if grain prices are low and heating energy prices are high. “Energy grain” produced specifically for the purpose of incineration, which could also be optimized through breeding efforts and cultivated with less effort (e.g. with reduced fertilization and plant protection measures), would further reduce the production costs.
Compared to heating oil, the most common fuel [source?] , The investment costs are still significantly higher at the moment. While a heating oil system is operational for around 7,000 euros on average, a grain furnace costs around 18,000 euros, although it must be taken into account that the price range of equivalent systems can fluctuate by up to 100%. The running costs are also up to 20% higher with such a small model (€ 3120 heating oil, € 3730 grain), but they are reduced in proportion with increasing performance. In the case of large models (> 75 kW), grain heating during operation is just as expensive or cheaper than heating oil systems (100 kW: € 13,860 heating oil, € 12,450 grain).
This compensation takes place solely through the fuel price, which is only half as high as that of heating oil, and in the case of less quantities it even drops to zero and then makes even the smallest systems up to 25 kW economical (status: 2006). The use of reduced grain in furnaces with a higher system output (25 to 100 kW) is economically particularly favorable, since the share of (low) fuel costs in the running costs increases.
Grain burning outside of the German-speaking area
The use of grain as fuel has so far been largely restricted to Germany, Austria and Denmark. Important framework conditions for the spread of grain burning are high energy prices, low prices for grain (or a sufficient supply of low-priced under-grains) and legal security for the use of the fuel.
In Denmark (compared to Germany) very high heating energy prices as well as the lack of exhaust gas standards for combustion systems favored the rapid spread of grain incineration systems since the 1990s. In 2002, more than 10,000 such systems were already in operation here (compared to around 100 in Germany at the same time).
Political positions
There have been several concerns about the use of grain as fuel. The main criticism was the use of food as an energy source. The different positions go beyond the parties. While the Evangelical Church of Westphalia in a joint statement with the dioceses of Münster, Paderborn and Essen criticized the burning as “devaluing the daily bread and the work of the farmers”, other voices in the Evangelical Church were more in favor of it also a climate-protecting potential that helps to preserve creation. The BUND criticizes that such a use is contrary to the "land use of tomorrow" and states that "[...] burning a food product such as grain that is completely out of the market in terms of quantity [...] is a declaration of bankruptcy in terms of agricultural policy". Basically, the legislature tries to meet ethical objections by restricting them to reduced grain and waste grain. For example, the classification of grain as a standard fuel for small firings applies exclusively to grain that cannot be used as food or animal feed.
proof
- Board of Trustees for Technology and Construction in Agriculture, Agency for Renewable Raw Materials (Ed.): Heating with Grain - and what you need to know about it , KTBL-Heft 74, 2007, ISBN 978-3-939371-50-2
Individual evidence
Most of the information in this article has been taken from the sources given under references; the following sources are also cited:
- ↑ Karsten Block: Grain price for harvest 2000 in the cellar - is energetic use an alternative? , March 7, 2001, online ( memento of October 25, 2006 in the Internet Archive ). Retrieved October 8, 2015.
- ↑ a b Board of Trustees for Technology and Construction in Agriculture, Agency for Renewable Raw Materials (Ed.): Heating with Grain - and what you need to know about it , KTBL-Heft 74, 2007, ISBN 978-3-939371-50-2
- ↑ oA: Grain Burning: Grains of Energy as an Opportunity for Agriculture , www.nachwachsende-rohstoffe.info, September 29, 2005, accessed on April 24, 2008
- ↑ a b See the resolution: Ministers of Agriculture Conference on September 6, 2002 in Bad Arolsen , Item 4.9: Resolution to expand the use of renewable raw materials for energy use : "The Agriculture Ministers and Senators of the Länder are of the opinion that [... ] In order to secure the social acceptance of such a development, a broad public discussion must first be made, in which the question of the ethical justifiability of the energetic recovery of grain must also be addressed […] “ PDF Online ( Memento des original of June 18, 2007 in Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ Anonymous: ABG Frankfurt Holding Wohnungsbau- und Beteiligungsgesellschaft mbH, Frankfurt: Energie vom Acker In: VerbandsMagazin, Landesausgabe Hessen, 2/2007, pp. 36–37
- ↑ a b Handbook: Bioenergie-Kleinanlagen , Fachagentur Nachwachsende Rohstoffe eV , Gülzow (2007), second, completely revised edition, 224-page pdf or booklet ( ISBN 3-00-011041-0 )
- ↑ ATZ Development Center, 2008: Small combustion system for grain and straw. Final report. ( pdf )
- ↑ Dr. Hans Hartmann, Norbert Hopf, Paul Roßmann, Armin Bimüller, Peter Turowski, Frank Ellner-Schuberth, 2007: Grain grains as fuel for small firings - technical possibilities and environmental effects. Reports from the Technologie- und Förderzentrum Straubing (TFZ), no. 13. ( pdf ( memento of the original from May 8, 2010 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link accordingly Instructions and then remove this notice. )
- ↑ Agency for Renewable Raw Materials (FNR): Energetic use of grain, stalks and other alternative biofuels for heat supply - Permission law ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ 1st BImschV, version 2009 (PDF; 579 kB), §3.8
- ↑ a b 1st BImschV, version 2009 (PDF; 579 kB), §5.3
- ↑ Andreas Gaisbauer: Future fuel biomass - energy grain? , Diploma thesis for obtaining the Magister degree (FH) for the FH diploma course Product and Project Management at the University of Applied Sciences Wiener Neustadt for Economics and Technology, 2003, p. 28.
- ↑ Claus Hermann Kühl: State of the art in straw pelleting, grain and straw burning in Denmark. In: KTBL technical talk "Energetic use of grain in small combustion systems" - 12./13. February 2003, abstracts of the articles, online ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.
- ↑ Joint responsibility for land and creation ( page no longer available , search in web archives ) Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. , Declaration by the Westphalian-Lippian Agricultural Association, the Archdiocese of Paderborn, the Dioceses of Münster and Essen as well as the Evangelical Church of Westphalia and the Lippe Regional Church
- ↑ Dr. Clemens Dirscherl: Pros and cons of grain burning for energetic use - A summary of the arguments as a contribution to an ethical judgment , Aktuell Editorial, October 7, 2005, online ( Memento of the original from December 24, 2007 in the Internet Archive ) Info: The archive link was inserted automatically and not yet tested. Please check the original and archive link according to the instructions and then remove this notice. , Accessed May 15, 2008
- ↑ Growing and burning of grain for energy production? In: BUNDposition, April 2006.
Web links
- Heating with grain and stalks. Brochure (28 pages) on technical and legal framework conditions, development and profitability. FNR, 2007. (PDF, 2 MB)
- Heating with Wheat - Detailed information on the practice of heating with grain
- Comprehensive information from the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) on the amended 1st BImSchV (12/2009), including the legal text, questions and answers and background information
literature
- Fachagentur Nachwachsende Rohstoffe eV : Handbook: Bioenergie-Kleinanlagen , Gülzow (2007), second, completely revised edition, ISBN 3-00-011041-0 , available as a PDF