Patent Application
20120121239
The invention relates to a device for processing substances, in particular digestate or digestate mixtures and more generally to the processing of substances that are to be processed for treatment by application of heat.
Various devices are used, for example, for post-processing of digestate or a mixture of digestate and other substances from a process, e.g., a fermentation process. In the post-processing, the digestate, which arrives with a temperature of about 35° C. from the process, is post-processed for a certain amount of time at a higher temperature level. As a rule the digestate includes a large amount of liquid, in particular water, often at a level greater than 50%, requiring additional processing of the digestate in order to significantly lower the water content, so that composting, in particular, becomes possible.
To accomplish the required heating, an airflow that has been heated up in a tube is often blown through a floor plate of a processing container into the area of the digestate. This measure is to achieve a homogeneous distribution of the heated medium air in the digestate, such that it is heated as much as possible by the air. This process is very drawn out due to the low specific thermal capacity of air, because air that cools down when passing through the digestate must be collected as exhaust air and reheated before it can be blown into the inlet of the processing container. Using this procedure, heating up the digestate requires a large number of cycles. It also means that a great amount of energy is required to heat up the air, with this energy requirement increasing with the number of required cycles.
It is therefore the objective of the invention to provide a device of the aforementioned kind that works significantly more effectively with regard to the required processing period and associated energy requirements.
This objective is achieved by a device for processing digestate or digestate mixtures (2), wherein the device includes a floor (3) for placing the digestate (2), whereby the floor (3) is gas-permeable, and whereby the floor (3) includes an inlet device (4) that can be connected to a line (6) for introducing a gaseous medium into the floor (3). The floor (3) configured such that the gaseous medium can flow through at least parts of the floor (3) for aerating the digestate (2), whereby a heating device (6b) is provided in the line (6) for the purpose of heating the gaseous medium that is flowing through the line (6). At least one heating element (5) is provided in the floor (3) of the device. The heating heating element (5) is configured and arranged to be in contact with said digestate material (2).
In one embodiment, the floor (3) is part of a container (1) for receiving the digestate or the digestate mixture (2). The container (1) may include at least one outlet device (1a) for discharging a gaseous medium that is located in the container (1). In another embodiment, the inlet device (4) for introducing the gaseous medium is connected to a line (6). The outlet device (1a) and the inlet device (4) may be fluidly connected to each other via line (6) for recycling of the gaseous medium from the outlet device (1a) to the inlet device (4).
In yet another embodiment, the line (6) may be switched such that is can be fed alternatively or in addition to the gaseous medium coming from the outlet device (1a), with fresh air from the outside of the container (1).
In another embodiment, the heat-up of the digestate or the digestate mixture (2) may be carried out at least in part by heating the floor (3) of the container (1) using a heating element, whereby the heating element is different from the gaseous medium.
According to the invention, a heating device is provided in the bottom of the device which can be a part of the processing container. In this manner, a heated area is available through the bottom for the substances to be processed, in particular digestate, this area heating the substances “from the bottom” with a significantly reduced energy consumption. Thus, heating the substances becomes significantly more effective. In addition, with closed containers significantly fewer cycles are required for reheating the exhaust coming out of the container than with the conventional method.
The invention will now be explained in detail based on the exemplary embodiments shown in
The device shown in
When taken from the fermentation process, the digestate material typically has a temperature of about 35° C., which needs to be raised to a significantly higher temperature level for processing. This increase occurs using the gas supplied via line 6, or the air supplied in this manner, respectively, which enters the container 1 via the permeable floor 3 and which is in this manner distributed under pressure in the digestate material 2. In addition, a heating device 5 is provided in the floor in direct proximity to the digestate 2 and is preferably provided in the floor 3, with a heating substance that is heated via the heater 5a flowing through it using a pump 5b. In this manner, the substrate to be processed is heated due to direct heat conduction. The supplied air (or gas) enters the container 2 as shown by the arrows P, and is distributed in the digestate material 2, flows through it and also heats it, and can be recirculated again (via valve 6d back into heater 6a) as cooled down exhaust air via the outlet 1a. This avoids a heat loss of the air through long transport paths and reduces energy consumption. The same energy can thus affect a significantly better heat-up of the digestate 2.
Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.
