WO2018158717A1

WO2018158717A1 - Loading system for pyrolysis machines

Info

Publication number: WO2018158717A1
Application number: PCT/IB2018/051303
Authority: WO
Inventors: Antonio La Gatta; Umberto La Gatta
Original assignee: K-Teck SA
Current assignee: K-Teck SA
Priority date: 2017-03-03
Filing date: 2018-03-01
Publication date: 2018-09-07
Anticipated expiration: 2019-09-03
Also published as: WO2018158717A9

Abstract

System for loading a pyrolysis reactor with organic matrices of various nature and/or waste material to be used on pyrolysis machines, constituted by an outer cylinder provided with a feeding hole, an inner cylinder serving as a shutter, said cylinders being such as to slide into each other, a head provided with gaskets and fixed to the inner cylinder. The inner cylinder is connected to an actuator of the electrical or hydraulic type with a control unit connected to a position and/or speed and/or pressure sensor.

Description

LOADING SYSTEM FOR PYROLYSIS MACHINES

TECHNOLOGICAL SECTOR

The industrial sector, among others, requires efficient and reliable loading and transport systems. There are some systems, such as those normally used in pyrolysis plants, which are a drop or screw type, and at the same time require more or less precise dosing systems to ensure optimal operation of the system in which they are integrated. Due to their intrinsic complexity and the nature of the material being loaded, often such systems are subjected to frequent scheduled and extraordinary maintenance, with inevitable downtimes.

PRIOR ART

Pyrolysis plants, which mainly use wood chips or wood pellets for biomass, use drop or screw type biomass reactor loading systems, also called passive systems, having to adopt techniques and complex mechanisms so as to prevent introducing excessive amounts of material, and the simultaneous release of synthetic gas or syngas, produced by the process itself. As noted, these systems are very complex, expensive, and subject to prolonged downtime, due to the frequent maintenance necessary and for the no less frequent jamming phenomena. They also have complexities and uncertainties regarding the amount of material introduced. Another limitation of the current systems, and not only of the drop type, but also for example of the belt type, or those with closed or semi-closed screw systems, is the operating range depending on the size and the purity of the material to be loaded. In fact, recommended ranges limit the operation of such systems with different materials. Other limitations of the current systems are related to the lower effectiveness in the sealing of the reaction chamber. On one hand this leads to the loss of highly flammable syngas and on the other the intake of air and therefore oxygen in the chamber producing a combustion reaction and not pyrolysis. This in turn affects the efficiency of the process and the nature of the syngas. DESCRIPTION OF THE INVENTION

The main innovation of this system compared to those of the known art, is that the system is active, that is, the loaded material is conveyed mechanically during the entire loading phase. This makes the loading system independent of the size of the loaded/conveyed matrix/biomass. In addition, due to its specific configuration and thanks to specific technical devices the system is able to overcome the limitation of mechanical jams, and if oversized components get through it is able to fragment/shear them, automatically reducing them to a conveyable size.

The system is substantially composed of two coaxial cylinders, a piston head and a drive system which can be of the electric (linear motor, screw motors), hydraulic, or pneumatic type.

The thick external cylinder, the thickness of which is optimized for the tangential pressures to which it will be subjected, is static. It has a suitably sized hole with a specific shape to cut the material and optimize the forces that push the material inside, through which the material to be transported enters. The shape of the entry hole is designed to generate a radial force towards the center which produces a biomass containment effect during the injection process. At an opposite end, there is the piston anchoring system (electric/hydraulic/etc.) which will transmit the motion to the inner cylinder. The walls of this cylinder are rectified, lapped, quenched, and chromed to ensure that the surface is unaltered over time from the abrasive/corrosive action of the transported material.

The inner cylinder is itself composed of two components, a cylinder that acts as a shutter, and a head, "piston head" that will have multiple functions. It breaks up the material that could not pass into the loading system because of its size. Its tolerances make it possible to keep the walls of the external cylinder clean of the residues of the matrix/biomass. It also houses pneumatic/oleodynamic expansion gaskets that keep the system under pressure. The sealing system is controlled by means of the valves which control when to put the system under pressure and when to release the pressure. This method of control prevents the seals from breaking, in fact if they were fixed, when they pass through the hole for loading they would tend to expand and in the subsequent closing phase would be cut by the system itself, losing effectiveness. In our system, the gaskets in the resting phase are inside their seats and thus are not subject to cuts and breaking during the material loading phase. Once the feed hole is free, the system automatically pressurizes the gaskets which, when expanded, will adhere to the inner walls of the outer cylinder, creating the seal. This seal control system also facilitates maintenance since during the replacement phase putting the gaskets under pressure pushes them out of their seat, making the replacement operation quick. The specific shape of the "piston head" also allows one or more digital probes to be housed inside to measure various parameters. Particular channels allow, if necessary, the injection of fluids into the loading system, when the material is being conveyed to the pyrogasification reactor. These channels can also be used for the collection and analysis of the syngas before sending it to the combustion process. The pneumatic/oleodynamic expansion sealing system seals the inlet channel and thus prevents syngas from escaping, and does not allow air, and therefore the oxygen in it, to enter the combustion chamber. All this translates into greater safety for the environment, people, and the location in which the system will be installed. The piston head is in turn equipped with a "head punch" which, under normal conditions of use, creates a channel inside the loaded material, thereby reducing the internal tensions due to the pressure exerted during loading. Thus it prevents material from compacting and creates less friction on the walls of the outer cylinder, but in extreme conditions it is used as a ram, to break up accumulated material.

The internal cylinder acts as a shutter for the material feed hole on the outer cylinder. The combined work of the hole on the external cylinder and the inner cylinder, their sizing and reciprocal positioning, facilitate the loading of a very accurate amount of material that can be transported inside the reaction chamber. The system allows such precise control as to allow the quantity of material to be dosed with absolute accuracy. The internal cylinder has inserts made of self- lubricating material so as to prevent contact between metal surfaces and at the same time to minimize friction between the materials in contact, thus requiring less energy for their operation. The system may be driven by different types of motors, as described above, which may be of an electrical, oleo-dynamic, or pneumatic nature, but if required in special cases can also be of the manual type. The precise control of feed rates is another innovation introduced in systems of this type, enabling the precise control of the pyrolysis reaction and therefore the thermal process taking place in the reactor, thereby allowing the quantity and quality of the syngas produced to be modulated. The system can be installed in various types of plants, whether new or existing. It can be mounted in various positions, whether horizontal, vertical or with more or less wide angles of inclination, either positive or negative. This makes the system flexible and high performance. The few components it is made of make it reliable and with a very low maintenance cycle.

Moreover, the forward speed of the piston is proportional to its position because while the system must ensure continuous feed, the density of the material increases with the forward movement of the piston.

The system therefore uses a predictive logic or a feedback logic. In the predictive logic a simple third order polynomial function of the following type is defined V = f(P)=a+bP+cP^A2+dP^A3 where V is the Speed, P is the position, and a, b, c, and d are experimentally determined coefficients that depend on the geometry of the cylinder and the material. In most simplified applications, a=l, b=-0.9, c=0, and d=0 can be used.

P=0 cylinder open P=l cylinder closed

In this case V is the piston speed normalized to 1 V=0 stopped piston V=l maximum feed speed.

In contrast, in the feedback logic the feed speed is a PID function of the piston thrust, that is the reaction force of the material acting on the piston.

V = f(S)=pS+dS'+i*integral (S), where V is the piston forward speed and S is the thrust exerted by the piston, p, d, and i are the proportional, integrative and derivative coefficients of the PID function.

In brief, the control systems introduced make it possible to take into account not only the reactor feed speed, but also the speed depending on the matrix/biomass used, since the behavior of the latter can vary considerably depending on different parameters such as particle size, humidity, specific density, elastic modulus, etc. PREFERRED EMBODIMENTS OF THE INVENTION

The preferred embodiment of the system is a system for loading and conveying wood and non-wood biomasses, inside the chambers in which the pyrolysis and/or combustion process is carried out. Nevertheless, this system can be used in all those cases where there is a need to convey certain quantities of materials, reduce the phenomenon of compacting and break up any components with dimensions that are not suitable for the size of the chamber, even of another nature, and where there is the need to control the speed of advancement of the same.

By way of example, the following drawings are attached.

Figure 1 shows an overall view of the system,

Figure 2 shows the external cylinder,

Figure 3 shows the inner cylinder,

Figure 4 shows the head punch,

Figure 5 shows the piston head with the relative sections.

As regards the above and the attached drawings the following claims are expressed.

Claims

1. Loading system for a pyrolysis reactor, suited to load organic matrices of various nature and/or waste material to be used on pyrolysis machines, characterized in that it comprises an outer cylinder provided with a feeding hole, an inner cylinder serving as a shutter, said cylinders being such as to slide one inside the other, a head provided with gaskets and fixed to the inner cylinder, and wherein said inner cylinder is connected to an actuator of the electrical or hydraulic type with a control unit connected to a position and/or speed and/or pressure sensor.

2. System according to claim 1, characterized in that the gaskets of the head are pneumatic/hydraulic expansion gaskets.

3. System according to claim 2, characterized in that it is managed by an electronic control which, according to the position of the inner cylinder, allows the expansion of the head gaskets to be activated.

4. System according to claim 3, characterized in that it is capable of detecting possible breakages of the head gaskets by monitoring the pressure drop in the gasket feeding pipes.

5. System according to claim 1, characterized in that it comprises at least one punch connected to the head and intended to be used to break down any agglomerated material.

6. System according to claim 1, characterized in that the outer cylinder and/or the punch are provided with a hole for the injection of the process fluids.

7. System according to claim 1, characterized in that the surfaces of the cylinders are rectified and/or hardened and/or chromed and/or provided with hard metal inserts.

8. System according to claim 1, characterized in that the inner cylinder is provided with inserts made of a self-lubricating material.

9. System according to claim 1, characterized in that it is provided with probes suited to be used to collect technical data and/or syngas samples.

10. System according to claim 1, characterized in that it allows the advance speed V of the inner cylinder to be controlled according to the quantity of material needed by the reactor positioned downstream, through a suitable external control signal or in a predictive manner according to the polynomial equation V=f(P)=a+bP+cP^A2+dP^A3, where V is the speed of advance of the inner cylinder and P is the position of the latter.