APPARATUS AND A METHOD FOR RECOVERY OF MEAL

Abstract

The present invention relates to a process for continuous manufacture or recovery of meal and oil from organic material. More specifically the present invention relates to a device and a method for regulating the energy usage and distribution of energy within the system for maintaining continuous production of meal and oil.

Claims

1-20. (canceled)

21. A method for recovery of meal from organic material, the method comprising; transferring the material to a pre-dryer for evaporating a portion of the water phase from the material, said pre-dryer being a steam boiler receiving external energy to heat up the material in the pre-dryer and generate steam, and transferring the material to a secondary dryer for removing more of the water phase from the material; wherein the removal of water in the secondary dryer is a two-step process of: transferring the steam generated in the pre-dryer to the secondary dryer to heat up the thermal surfaces of the secondary dryer and thereby the material in the secondary dryer, and blowing dry air though the secondary dryer, where it blends with the material during evaporation and the air exits saturated out of the secondary dryer.

22. The method according to claim 21, wherein the material is heated up in one or more cookers before it is transferred into the pre-dryer.

23. The method according to claim 22, wherein heating is performed in two steps in a pre-cooker to pre-heat the material and in a cooker to heat the material further.

24. The method according to claim 21, wherein a steam generated in the pre-dryer is partially directed to a cooker, where it condenses on thermal surfaces on/around the cooker.

25. The method according to claim 21, wherein water condensate from the secondary dryer and cooker is transported to the pre-cooker to pre-heat the material.

26. The method according to claim 22, wherein an oil phase is separated from the material in a separating device after heating the material in one or more cookers and prior to transferring it into the pre-dryer.

27. The method according to claim 21, wherein the energy provided to the pre-dryer is sufficient for performing the steps thereof.

28. The method according to claim 21, wherein material is transferred into pre-dyer to keep constant weight of material in the pre-dryer.

29. The method according to claim 21, wherein fixed external energy is introduced to the pre-dryer and more material is pumped into the secondary dryer if the water content of the meal is too low.

30. The method according to claim 21, wherein fixed external energy is introduced to the pre-dryer and less material is pumped into the secondary-dryer if the water content of the meal is too high.

31. The method according to claim 21, wherein the water content of the air leaving the secondary dryer is reduced in a water scrubber.

32. The method according to claim 21, wherein the organic material is from fish.

33. The system according to claim 21, wherein the organic material is from meat.

34. An apparatus for recovery of or meal from raw material, the apparatus comprising; a pre-dryer for removing a portion of the water phase from the material, said pre-dryer being a steam boiler receiving external energy to heat up the material in the pre-dryer and generate steam, and an secondary dryer for removing more of the water phase from the material in, wherein the secondary dryer comprising a heat exchange element to receive steam generated in the pre-dryer to heat up the material in the secondary dryer, and the secondary dryer further comprising an air inlet for receiving dry air being blown into the secondary dryer, where it blends with the material during evaporation and an air outlet for directing saturated air out of the secondary dryer.

35. The apparatus according to claim 34, further comprising one or more cookers to heat up the material before it is transferred into the pre-dryer.

36. The apparatus according to claim 35, wherein heating is performed by a pre-cooker to pre-heat the material and in a cooker to heat the material further.

37. The apparatus according to claim 34, further comprising separation device 3 for separating the oil phase from the material.

38. The apparatus according to claim 34, further comprising a piston pump for loading the material into the cooker.

39. The apparatus according to claim 34, wherein a piston pump is positioned after the cooker to pump the material into the separation device.

40. The apparatus according to claim 38, wherein the piston pump comprises a stirring means to bring the material to a homogenous state before it is transported into the separation device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0039] The present invention will become more fully understood from the detailed description given hereinafter and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention. The embodiments shown in the drawings are explained with reference numbers. The term system is used here below when describing the interplay of the method and the apparatus.

[0040] FIG. 1 shows a schematic drawing of system for recovery of fish meal and oil from raw material, where the route of the material through the system is shown as well as the input energy and the distribution of energy through the system. The mechanical components of the system comprise a preparation device, such as a hasher (not shown), a cooker 1, a cooker 2, separating station 3, a pre-dryer 4 and a secondary dryer 5. The figure shows an embodiment of the invention where the only component receiving external energy is the pre-dryer 4 (being a steam boiler) and explains how the energy usage and distribution of energy within the system is controlled for maintaining continuous production of fish meal and oil. The figure also shows a water scrubber 6, which is used to cool down air coming from the secondary dryer 5. The route of the material through the system is shown with lines and arrows from raw material entering the cooker 1, separation of the oil phase from the water/solid phase in the separating station 3 and removal of the water phase in the pre-dryer 4 and the secondary dryer 5 before delivering the solid phase (dry meal) at the end of the process. The figure also shows how the input energy is transformed into steam and condense for driving the remaining components of the system. The energy distribution and the management of the system will be further explained in drawings 2-4, showing that the components of the process and generation of high quality low-heat generated fish meal is actually regulated by fully using the energy in the system.

[0041] FIG. 2 further explains the route of the material through the system. The raw material is most often processed by some kind of preparation device (not shown) to grind the raw material before it undergoes the process of boiling, separation of the oil phase from the rest and then evaporation of the water phases to deliver the meal. The raw material is then pumped into the cooker 1, which is a tube-boiler in this embodiment. The material is pre-heated in a cooker 1 to around 35 C. The material is guided into the cooker 2 by some transport means, such as a winding tube. The material heats up to around 85 C. in the cooker 2 as it moves towards an out-feed opening together with a precipitate of bones and sand. The precipitate is separated from the material before the oil phase is separated from the solid/water phase in a separating station. The heat of the material decreases from 80 C. to between 50-60 C. during the separation phase (shown as approximately 55 C. in the drawing). The material comprising the water/solid phase is transported from the decanter 3 to the pre-dryer 4 by a transfer means such as a screw conveyor (not shown).

[0042] The pre-dryer of the system heats the material to around 100 C. by heating the inner surface of the pre-dryer. Therefore, it is important to continuously scrape the material from the inner surface of the cylinder in order to prevent the material from burning if it stays to long adherent to the inner surface. The pre-dryer can be positioned on load cells and subjected to constant weighing to regulate the in-feeding into the pre-dryer. A pump is positioned between the pre-dryer 4 and the main evaporator/dryer 5. This pump may function as the main controller the material through the whole unit. In this part of the process, the consistency of the material is high. In the pre-dryer, up to about 70% of the water that is removed by boiling. The remaining material proceeds as a slurry to the secondary dryer 5, where the rest of the water to be removed evaporates, leaving the meal at 40 C. as it exits the device and the process.

[0043] The after-dryer/secondary dryer 5 is built as a cylinder with a centrally arranged rotor along the cylinder. The material which enters the secondary dryer is a slurry paste and devices such as scrapers can be used to rotate the paste to interact with the air-phase therein. The slurry paste material is 100 C. as it enters the secondary dryer, but as the paste reacts with the air phase and the hot surfaces of the cylinder the heat leaves the paste with the water molecules. The dry meal (8% water) is around 40 C. as it leaves the system and as the meal leaves the secondary dryer it passes through a grinder to grind the meal.

[0044] FIG. 3 demonstrates the utilization of input energy in the system and re-use of that energy to perform the process of the unit for generating high quality low-heat generated meal. Instead of following the material through the system, the route of the energy is followed in this drawing. As the pre-dryer is a steam boiler, the terms steam boiler or pre-dryer are used equally for the purpose of describing the drawings. The steam boiler/pre-dryer 4 receives energy from a source outside the system. The steam boiler heats the inner surface (the cylinder) of the pre-dryer. The steam (100 C.) generated in the steam boiler is transported therefrom to the secondary dryer 5 and to the cooker 2. The steam condenses in part on the thermal surfaces of the secondary dryer and the energy released by heating the secondary dryer is used to trigger the phase change therein. To keep the phase change in process and to remove the stem formed, air @ 20 C. is circulated through the secondary dryer. The air blends with the slurry and meal through an action of a rotor (not shown). Due to the phase change of the temperature of the blend is maintained @ 50 C., but in that manner energy flows continuously into the blend through thermal surfaces of the secondary dryer. The air leaving the secondary dryer is 60 C. and is blown through a washing tower (see FIG. 4). In the secondary dryer, about 60% of steam from the pre-dryer 4 is condensed, while the rest of steam continues to the cooker 2 and condenses on its thermal surfaces. The energy, which is released in the cooker 2 heats the material from 35 C. to 85 C. in the cooker 2. The water condensate from the secondary dryer 5 and cooker 2 is transported to the cooker 1 and the energy released from the condensate is used to heat the raw material in cooker 1 from 5 C. up to 35 C. and condensed water directed out of the system at 30 C.

[0045] The heat of the material decreases from 80 C. to between 50-60 C. during the separation phase in the decanter 3. The material is transported from the decanter 3 to the pre-dryer 4 by a transfer means such as a screw conveyor (not shown). The screw-conveyor can be positioned inside the piping or casing which is heated by a portion of the steam generated in the pre-dryer 4. This is to prevent further loss of temperature in the material.

[0046] FIG. 4 shows how air from the secondary dryer is cooled down according to one embodiment of the present invention. The secondary-dryer in this embodiment is built as a cylinder with a centrally arranged rotor along the cylinder. Around the rotor is a coat/cover 7, where steam from the pre-dryer is condensed in the cover. The slurry paste material entering the secondary dryer is rotated in the cylinder to allow it to interact with air which is blown into the cylinder at the entry end of the secondary dryer. In this embodiment the air is at 20 C. when it is blown into the secondary dryer and the slurry paste material is 100 C. as it enters the secondary dryer. The reaction of the material with the drying air and the hot surfaces of the cylinder causes evaporation from the material and energy leaves the system in the form of saturated air, which is between 50 and 60 C. as it leaves the secondary dryer 5. Although most of the meal leaves the secondary dryer 5 as grinded material, some fine meal particles leave the secondary dryer 5 with the air. The fine meal is separated in a air washing tower (water scrubber) or cyclone 7 and is either directed to join the grinded meal from the secondary dryer or is stored separately. The water scrubber 6 receives air from the secondary dryer 5 at a temperature of about 60 C. The air is cooled down to around 20 C. and then directed again into the dryer 5 to further dry the half-dry paste from the pre-dryer 4. Although a water scrubber is shown herein, warm humid air can simply be blown out of the secondary dryer 5 and dry air can be injected into the secondary dryer to aid with the evaporation process according to the present invention.

[0047] The present invention covers further embodiments with any combination of features from different embodiments described above. Reference signs in the claims are provided merely as a clarifying example and shall not be construed as limiting the scope of the claims in any way. The present invention also covers the exact terms, features, values and ranges etc. in case these terms, features, values and ranges etc. are used in conjunction with terms such as about, around, generally, substantially, essentially, at least etc. (i.e., about 3 shall also cover exactly 3 or substantial constant shall also cover exactly constant). The terms a, an, first, second etc do not preclude a plurality