SE528657C2 - Use of a mixture of starch and grain peel as biofuel - Google Patents

Abstract

The present invention relates to a bio-fuel mixture comprising starch and cereal husk, wherein the starch is present as a flour obtained from wheat, barley, rye, triticale, oat, rice, maize and/or potato, and the cereal husk is obtained from the de-hulling of cereal grains such as wheat, barley, rye, triticale, oat, rice and/or maize, wherein the content of starch flour ranges from 20% (w/w) up to 80% (w/w), the remainder being hull. The mixture is preferably used as a bio-fuel.

Description

528 657 2. The low bulk density and coarse structure of the flour make it difficult to move around.

A mixture with starch flour dramatically improves this situation: the total silicon content of the mixture is satisfactory, and the flowability properties and bulk density of the flour give a mixture which is good.

Flour that is rich in starch can also be used as feed for farm animals, especially horses and pigs. However, such flour needs to be supplemented with various feed additives to form a complete feed. Such feeds are normally produced from different ingredients which are stored in different storage containers such as silos after which the ingredients are fed to a mixer. The problem is then to feed out the cereals, and then especially the oatmeal in a satisfactory, undisturbed way, because, as mentioned above, it has a tendency to coagulate and become non-runny.

The present invention describes a process in which the husks of cereals are mixed with the flour in proportions ranging from 30% husk / YO% flour (based on dry weight) to 70% husk / 30% flour, which produces an excellent free-flowing product.

In particular, the mixture has a low overall silicon content with a generally low ash yield, which makes it an excellent biofuel.

SUMMARY OF THE PRESENT INVENTION It has been discovered that a freely flowable mixture can be produced by mixing the husks of cereals with flour in proportions ranging from 30% husk 70% flour (based on dry weight) to 70% husk / 30% flour. In this description, starch flour is the starch-rich endosperm material obtained from dry grinding of peeled cereals or potato flour. Cereal husks are the material that is considered by grain millers to be the coarse husk that is removed from the grain with the help of peeling equipment. Cereals are routinely peeled in this way, before further processing. In a preferred embodiment of this invention is grain oats, in which oatmeal is mixed with husks, preferably oat husks removed from oat grains during peeling, to produce a free-consuming biofuel with an energy value between 4000 and 4100 kcal / kg (17-185 MJ7kg; 4. -5.1 MWh / ton). 528 657 The material is much more suitable as a fuel than any of the starting materials in two different respects: it is relatively easy to move due to its improved flowability properties, and the ash level (between 2% and 5%) is acceptable for use in many types of energy production burners . Furthermore, the ash melting temperature in the mixture is higher than 1200 ° C as opposed to below 600 ° C for the flour alone. This is very beneficial because ash that melts at low temperatures can be a real problem in many types of biofuel burners.

DETAILED DESCRIPTION OF THE INVENTION The inventors have developed an excellent free flowable biomass fuel based on a mixture of starchy flours which are dry ground from cereals or from potatoes and the husk removed from the grain, and a process for the production of such biofuel. The fuel is ideal for combustion in that it has a calorific value that is characteristic of many carbohydrates and lignocellulosic materials, significantly improved flowability and handling properties compared to the original flour and shell raw material. In addition, the ash melting temperature of the mixture (above 1200 ° C) is very advantageous for a biofuel intended for many standard burners.

The invention is characterized by the combination of dry-ground flour from peeled cereals or potato flour with the cereal peels. removed from cereal grains by means of a peeler in a dry mixer of the type, or any other suitable dry mixer, in the proportions ranging from 20% flour / 80% husk to 80% flour / 20% husk, preferably in the range of 30% flour / 70 % shell to 70% flour / 3O% shell. The free-flowing material generated by mixing the components can then optionally be formed into pellets and / or briquettes or used directly as loose particles flowing out of the mixing step.

The material in any of the forms, ie. Free-flowing particles, pelleted or as briquettes can then be used as fuel in most types of burners, either for the production of direct heat, or for the creation of electricity.

The material can also be used as feed for farm animals, such as especially horses and pigs, supplemented with various feed additives to create a complete feed. 528 657 DESCRIPTION OF THE PREFERRED EMBODIMENTS Example 1 1000 kg of oat grains were peeled using a Buhler peeling system. This gave 306 kg of husk and 690 kg of grain. The resulting grains were then dry-milled with a "short-flour" grinding system, which gave a fraction of 312 kg of fine endosperm-rich flour and a coarser clarified fraction of 375 kg.

The flour was then mixed with the shell in the proportions 1 part flour to 1 part shell (25 kg + 25 kg), based on the dry weight, using a dry mixer. The resulting mixture was observed to have improved flowability properties compared with both the flour, which has a tendency to clump and cake, and the skin, which is very coarse.

The fuel value was evaluated using calorimetric techniques and the following results were obtained: Energy content SS-ISO 1928 MJ / Kg Kcal / Kg MWh / ton Calorimetric calorific value 17.12 4-76 (delivered) 4089 Calorimetric calorific value 5-17 (constant pressure) 18.61 4444 Effective heat constant pressure, delivered) .92 3802 4.42 Effective calorific value (constant pressure, dry-based) 17.52 4183 4.86 Effective calorific value (constant pressure, dry-based, ash-free base) 18.24 4354 5.06 The mixture had a measured ash content of 3.6%. The measured ash melting temperature was higher than 1400 ° C. The flour only is lower than 600 ° C.

Example 2 An additional portion of the flour treated as in Example 1 above was mixed with the husk, also prepared as in Example 1 above, in the proportions of 30% flour: 70% 528,657 husks (6 kg flour + 14 kg husks), based on dry weight. using a dry-mix gel. Again, it was observed that the flowability properties and handling of the mixture were very superior to those of each of the starting materials.

The fuel value of the material was evaluated using calorimetric techniques and the following results were obtained: Energy content MWh / flm SS-ISO 1928 MJ / Kg Kcal / Kg Calorimetric calorific value 16.96 4050 4.71 (delivered) Calorimetric calorific value 18.39 4392 Effective 15-11 (pressure) 4-29 (constant pressure, delivered) 3692 Effective calorific value 4-71 (constant pressure, dry-based) 16.97 4053 Effective calorific value 5-03 (constant pressure, dry-based, ash-free base) 18.09 4322 The mixture had a measured ash content of 4.6%. The measured ash melting temperature was again higher than 1400 ° C.

Example 3 An additional portion of the flour prepared as in Example 1 above was mixed with the shell, also prepared as in Example 1 above in the proportions 70% flour: 30% shell (14 kg flour + 6 kg shell) based on the dry weight, with using a dry mixer. Again, the flowability properties and handling of the mixture observed were much better than those of any of the starting materials. 528 657 The fuel value of the material was evaluated using calorimetric techniques and the following results were obtained: energy content MJ / Kg kcal / Kg MWh / ton ss-Iso 1928 Calorimetric calorific value 16.87 4027 4.68 (delivered) 'Calorimetric calorific value calorific value 18.97 pressure value 2730 15.33 3661 4.26 (constant pressure, delivered) Effective calorific value 17.55 4191 4.87 (constant pressure, dry-based) Effective calorific value 17.84 4259 4.95 (constant pressure, dry-based, ash-free base) The mixture had a measured ash content of 2.4%. The measured ash melting temperature was again higher than 1400 ° C.

The shell material normally has a size of 1 to 10 mm, in which oat shells have a size of 2 to 7 mm. This means that a similar straw material can be used and mixed with a powdery starch material after grinding down to a size of 1-10, preferably 2-7 mm. Thus, the term shell here includes straw material milled in this manner.

Claims (7)

528 657 REQUIREMENTS Use of a free-flowing biofuel mixture of starch flour and cereal husks, characterized in that the starch flour obtained from wheat, barley, rye, tritical, oats, rice, maize and / or potatoes is mixed with the husks obtained from the process of peeling cereals, cereal grains , rye, tritical, oats, rice and / or maize, which are then optionally pelleted and / or formed into briquettes and used as fuel for combustion either to generate direct heat or to generate electricity. Use according to claim 1, wherein the content of starch flour ranges from 20% (w / w) up to 80% (w / w), and the remainder is peel. Use according to claim 1, wherein the content of starch flour ranges from 30% (w / w) up to 70% (w / w), and the remainder is peel. Use according to claims 1-3, wherein the starch flour consists of at least one of the following; wheat, barley, rye, tritical, oats, rice, maize, potatoes or a mixture thereof and mixed with the cereal husks obtained from wheat, barley, rye, tritical, oats, rice or maize or a mixture thereof. Use according to claims 1-3, wherein the starch flour and the cereal shells are obtained from oats. Use according to claims 1-5, in which the ash melting temperature is higher than 1000 ° C. 7. The production of energy for the generation of direct heat or electricity by burning a free-flowing biofuel mixture containing starch flour obtained from wheat, barley, rye, tritical, oats, rice, maize and / or potatoes mixed with cereal husks obtained from the cereal peeling process such as wheat, barley, rye, tritical, oats, rice and / or maize in proportions ranging from 20% (w / w) shell 80% (w / w) flour (based on dry weight) to 80% (w / w) shell / 20% (w / w) flour, where the mixture is optionally formed into pellets and / or briquettes or used directly in the form of loose particles for combustion.