DE102007059982B4 - Pyrolysis system for carbonaceous feedstocks - Google Patents

Abstract

Pyrolysis system for carbonaceous feedstocks, comprising
a) a pyrolysis reactor (1),
b) a heating section (3) for heat transfer particles (10) and
c) a closed circuit of the heat transfer particles (10) through the pyrolysis reactor and the heating line, wherein
d) the heating section burner (11, 20), wherein the burners are heated with pyrolysis gas and
e) low-oxygen waste gases from the combustion can be introduced into the pyrolysis reactor (3) and form an oxygen-poor pyrolysis atmosphere in the latter,
characterized in that
f) the heating section has forced conveying means for the heat transfer particles (10).

Description

The Invention relates to a pyrolysis system for carbonaceous feedstocks, in particular regenerative biomass such as herbal substances, according to claim 1.

In a pyrolysis system of the type mentioned is pyrolysis, d. H. a thermal treatment with exclusion of carbon Input materials such as biomass (eg energy crops, lignocellulose etc.) or waste materials such as plastics etc., which are present to pyrolysis products, d. H. to solid pyrolysis, liquid or vaporous Pyrolysis condensate and gaseous Pyrolysis gas decomposes.

The Proportions of the aforementioned pyrolysis products are due to the composition and residual moisture of the starting materials in combination with various Process parameters, in particular the pyrolysis temperature, the pyrolysis time (Reaction time) and the heating and Abkühlparametern influenced.

The Pyrolysis temperature determined from the decomposition temperature and decomposition kinematics of the starting materials and is within the range between 400 and 600 ° C.

at the pyrolysis time (reaction time without heating and cooling periods) A distinction is made between areas that can be assigned to a process management.

A Fast pyrolysis - too known as flash pyrolysis a pyrolysis time below about 10 seconds pure reaction time. It serves to implement carbonaceous feedstocks such as Biomass with a particularly high yield of liquid pyrolysis condensate (Pyrolysis oil, bio-oil) and small amounts of solid pyrolysis and pyrolysis gas. A Fast pyrolysis takes place, for example, with biomass as feedstock preferably around 500 ° C, typically a proportion of pyrolysis condensate of 40 to 80% by weight and to biokoks (pyrolysis coke) of only 10 to 30% by weight established. In particular, wood and straw (lignocellulose) too over 50% to 80% to bio oil Liquefy (pyrolysis condensate).

From about 10 seconds reaction time, the fast pyrolysis goes into the area the so-called intermediate pyrolysis, in which, with increasing pyrolysis time, the proportions of the solid Pyrolysis coke and the pyrolysis gases to the detriment of the liquid ingredients increase.

Usually is the pyrolysis of the other two pyrolysis, the Pyrolysis and the pyrolysis condensate separated and becomes so z. B. as a fuel for the aforementioned pyrolysis usable.

The remaining liquid Pyrolysis condensate and pyrolysis are used as a mixture of these Components to an oil sludge (Bioölschlamm, Slurry) fed by the rapid pyrolysis of an entrainment gasification, where the said products in a substoichiometric oxygen stream atomized and to be gassed. For example, can be with an air flow gasification at high temperatures and pressures a virtually tar- and methane-free Produce crude synthesis gas at high sales, especially in a subsequent Synthesis to fuels and / or chemical precursors advantageous is.

pyrolysis systems of the type mentioned include a pyrolysis reactor in which the input materials are entered and as mentioned above thermally be converted to pyrolysis products.

In the EP 1 217 318 A1 a system for the thermal treatment of materials is described, comprising at least one reaction zone in a heated with heating means rotary kiln with at least one rotary screw. The rotary screw is heated by its own integrated heating medium and serves to transport the materials to be treated as well as additional heat-conducting particles through the rotary kiln. However, the particles do not serve for a heat input into the reaction zone, but rather an efficient heat transfer from the two heating means to the materials to be treated in the reaction zone.

In contrast, in the DE 10 2005 037 917 A1 describe a method for rapid pyrolysis of lignocellulose, in which the aforementioned particles are not only provided for heat distribution in the reaction zone, but in particular for the heat input, ie the heat transfer into the reaction zone. The particles are externally heated and introduced with the lignocellulose in the reaction zone, wherein the lignocellulose is heated in the reaction zone of particles. For an external heating of the particles, a countercurrent heat exchanger is proposed, wherein these flow through the particles and a flue gas stream in the opposite direction.

The said systems, in particular the heaters for a not taking place in the reaction zone heating of the aforementioned particles, have in a design on an industrial scale a size that for transport and / or mobile use z. B. are too large as a truck body. In particular, the previously turned on Countercurrent heat exchangers are realized as a drop tower for the particles and usually have a minimum height of 3 m.

From that Based on the object of the invention is a pyrolysis system of the type mentioned above for modify carbonaceous feedstocks so that they are already conceptually for the realization of compact decentralized systems is suitable. Furthermore, the modification is intended to achieve better adjustability and controllability of the heat energy flow over the Heat transfer particles in the pyrolysis reactor and thus a production of pyrolysis coke be made possible with adjustable particle size.

The Task is using a pyrolysis system with the characteristics of the first Patent claim solved. The back related to this Subordinate claims advantageous embodiments of the pyrolysis again.

The Pyrolysis system comprises at least one pyrolysis reactor and a Heating section for heat transfer particles, in a closed circuit through the pyrolysis reactor and the heating section are routed. It is essential, however, that the heating section for heating the heat transfer particle Burner, wherein the burner can be heated with pyrolysis gas and low oxygen emissions from combustion in the pyrolysis reactor can be introduced. The exhaust gases form a low-oxygen in the pyrolysis reactor pyrolysis, by B. preferably as an exhaust gas stream through the pyrolysis reactor be directed. The heating line is, if not a sheath the entire pyrolysis system encloses, by a volume in one casing educated. Furthermore, between housing and pyrolysis reactor a Connection provided. The housing and the connection to the pyrolysis reactor form a gas barrier and prevent gas exchange with the environment and thus a pour in from oxygen over the heating section in the pyrolysis reactor.

The Pyrolysis products leave the pyrolysis reactor after pyrolysis preferably in two streams, d. H. in a first fluid stream as pyrolysis condensate and pyrolysis on the one hand and in a second solid stream as a pyrolysis coke with the heat transfer particles on the other hand. It follows in a capacitor a separation of the first Material flow in liquid or aerosol-shaped Pyrolysis condensate and gaseous Pyrolysis. The pyrolysis gas is then preferably the burners of Pyrolysis system fed as fuel. Likewise, a separation takes place pyrolysis coke and heat transfer particles, preferably by means of sieves or magnetic separators. The pyrolysis condensate and the pyrolysis coke then become a suspension together (Slurry) mixed.

Preferably is at least one of the burners in the interior of the heating section or directed in the area immediately before the heating, wherein the hot ones Fuel gases the heat transfer particles in the heating section. More preferably, at least one of these burners is aimed directly at the heat transfer particles. Further preferably leads the cycle of heat transfer particles in or in front of the heat transfer line by at least one flame of a burner, d. H. all heat transfer particles go through in the heating or immediately before in the circulation at least one area of influence of the flame of a burner. In order to it will too on the heat transfer particles attached and consumed oxygen.

The Fuel gases go through together with the heat transfer particles the heating, transfer while continuing to heat to the heat transfer particles and afterwards as low-oxygen (as burned) exhaust gases together with the heat transfer particles introduced into the reactor.

To Passing through the heating section and before the exhaust gases (and the heat transfer particle) in the pyrolysis reactor, a measurement of the residual oxygen takes place in the exhaust through a lambda probe. This will be the oxygen consumption determined by the combustion and as a controlled variable of the combustion control (Control unit) supplied. These Arrangement is used for permanent combustion control, resulting in advantageously inhomogeneities of the burner fuel, d. H. the pyrolysis gas detectable and taken into account in the scheme are. The inhomogeneities based z. B. on a non-homogeneous composition of the carbonaceous Starting materials, the pyrolysis fluctuating conditions the pyrolysis products, d. H. Pyrolysis gas, pyrolysis and pyrolysis condensate can cause.

A optional temperature measuring device (eg thermocouple or pyrometer) In the area of the lambda probe measures the temperature of exhaust gas and / or Heat transfer particles before entering the pyrolysis reactor. Also, the temperature that the Specifies pyrolysis and thus for the packaging of the Pyrolysis products (eg in the current setting of the particle size) can be used, flows optional in the regulation of combustion with.

Combustion control takes place via a burner control. If the burners are directed into the interior of the heating section or into the area immediately before the heating section, a Control additionally via an addition of oxygen into the interior or immediately before the heating, ie there is a combustion control over the combustion mixture oxygen or air to fuel (pyrolysis gas).

According to the invention the heating section forced conveyor for the Heat transfer particles, more preferably at least one screw conveyor. With that the heat transfer particles forced in a particularly advantageous manner in the heating and in the context of the aforementioned cycle in an adjustable defined Time warmed up. Another advantage is the heating of the heat transfer particles as a bed or at least in permanent Contact with other heat transfer particles, with which heat between the particles is preferably interchangeable is and the heat transfer particles with the same or almost the same temperature, the heat transfer path leave and enter the reaction zone of the pyrolysis reactor.

As well gives the screw conveyor in the pyrolysis reactor exactly before the pyrolysis.

in the The result is a pyrolysis system that is characterized by an exact Verfahrensführbarkeit and thus exactly assemble pyrolysis products such. Legs reproducible particle size of the pyrolysis coke also with inhomogeneous starting materials characterized by the employment The heating section described is the realization of a compact design allows.

The Pyrolysis system is suitable for the implementation of pyrolysis with carbonaceous feedstocks with virtually all pyrolysis temperatures known in the art and times, in particular between 400 and 600 ° C, preferably between 500 and 550 ° C as well Pyrolysis times between preferably 1 and 200 seconds, more preferred between 5 and 100 seconds, more preferably between 10 and 120 Seconds. The process comprises a cycle for heat transfer particles, these being in a first step in the heating by a burner flame operated with the pyrolysis gas produced and heated in the exhaust gas, in a second step together with the exhaust gas and the carbonaceous feedstocks in the Pyrolysis reactor are introduced, the exhaust gases are the oxygen-poor pyrolysis form. The feedstocks then pyrolyze to pyrolysis products, wherein the pyrolysis gas used as fuel for the burner flame becomes.

The Invention will be described below with embodiments with reference to Figures closer explained. It demonstrate

1 a first embodiment of the pyrolysis system with indirect heating of the heating section,

2 a second embodiment of the pyrolysis system with indirect heating of the heating section,

3 a detailed view of the separator for a separation of pyrolysis and heat transfer particles according to 1 and 2 such as

4 an alternative separation device for a separation of pyrolysis coke and heat transfer particles in the in 3 corresponding detail view.

The pyrolysis system of the embodiments according to. 1 and 2 includes a pyrolysis reactor 1 and a heating section 3 of the aforementioned type, each equipped with forced conveyors.

The pyrolysis reactor each has a feed for heat transfer particles 5 and starting materials 6 and one derivative each for fluidic and solid pyrolysis products 7 respectively. 8th as well as one auger each 2 as a promoter for the heat transfer particles and the starting materials. The conveying direction 9 points in the direction of the derivatives 7 and 8th , where a separation of the material flow in a solid and a fluidic partial flow of material 12 respectively. 32 he follows.

The heating section 3 also includes a screw conveyor 4 for heat transfer particles 10 as well as burners 11 . 20 as a heating agent. The screw conveyor connects a collecting container 18 via a gastight feed 5 for heat transfer particles. The sump has its own burner 20 for heat transfer particles 10 on. Furthermore, in the field of gas-tight feed a lambda probe 33 for detecting the residual oxygen in the exhaust gas, preferably also used a temperature measurement.

The heat transfer particles 10 preferably comprise at least two heat transfer particle fractions which differ in their particle diameter. This has several advantages over one-size heat transfer particles. On the one hand, the heat transfer particles in the heating section take on a denser packing density (bulk density) and thus generally contain a higher specific heat energy density, but can also be heated more homogeneously due to the higher contact surfaces. On the other hand, they have a different heat absorption and heat release dynamics (heat capacity and heat transfer rate), whereby the Wärmeabgabege speed of the heat transfer particles on the feedstock in the pyrolysis reactor controllable and optimized in terms of isothermal pyrolysis as possible. The latter effect can also be realized within the scope of the invention by heat transfer particle fractions which differ in the thematic material behavior, in particular the heat capacity and / or the thermal conductivity, instead of or in addition to the particle size

In the 1 illustrated embodiment differs from the in 2 disclosed design in the arrangement of the burner 11 to the heating section. While the burners in 1 below the heating section 3 arranged the housing desselbigen illuminate from outside and heat, the burner gem. 2 used in the housing wall of the heating, wherein the flames of the burner are directed from above into the volume of the heating and also their exhaust gases from the heating via the supply of heat transfer particles 5 into the interior of the pyrolysis reactor 1 reach.

In contrast, the in 1 illustrated embodiment only one in the sump 18 directed burner 20 up, through the fuel gases in the volume of the heating 3 can reach. Because the heat transfer particles 10 in the collection container 18 already heated, counts in the context of at least this embodiment, the sump 18 to the heating section 3 ,

The solid pyrolysis products are present as pyrolysis coke, by the derivative 8th initially as a solid particle mixture with the heat transfer particles 10 in the fluidic partial flow of substances 12 jointly supplied to a separator for separating heat transfer particles and solid pyrolysis products.

In the example finds a first separation in a sieve 34 instead of. This is a first separation of a first heat transfer particle fraction 13 comprising the heat transfer particles having a particle diameter above the mesh size. To ensure that with the first heat transfer particle fraction no or only small amounts of pyrolysis coke 14 with is separated, the mesh size of this sieve 34 larger than the largest particle diameter of the pyrolysis coke 14 adjust. Since the pyrolysis system is designed as a mobile plant and for different starting materials and thus vary the particle sizes of the pyrolysis coke, the mesh size of the screen is preferably designed to be variably adjustable.

Are as in the embodiments provided at least two heat transfer particle fractions 13 . 19 provided with different particle sizes, is the sieve 34 for the deposition of the subsequent heat transfer particle fractions, a second sieve, in the examples a rotary sieve 16 nachzuschalten. In this, the fractions with smaller particle sizes from the unseparated part of the partial stream of material 15 separated and as a second particle fraction 19 in a second collection container 22 fed. The separated pyrolysis coke 14 on the other hand, it becomes a mixing chamber 28 fed.

The second heat transfer particle fraction 19 is then via an example snail-driven transport unit 17 from the second collection container 22 in the first collection container 18 implemented, there with the first heat transfer particle fractions 13 mixed and under the influence of the burner 20 and a combustion air supply 21 preheated (cf. 3 ). In this case, advantageously also a possibly still adhering to the heat transfer particles residues of pyrolysis products and / or oxygen is burned with. The exhaust gases are then shared with the heat transfer particles 10 comprising all heat transfer particle fractions 13 . 19 from the screw conveyor 4 through the heating section 3 promoted.

Is one of the heat transfer particle fractions 13 . 19 magnetic, the magnetic fraction separation separator is preferably a magnetic heat transfer particle magnetic deposition apparatus instead of a sieve.

Do all heat transfer particle fractions have a particle size above the mesh size of the sieve 34 on, a downstream rotary screen is not required. The pyrolysis coke can be fed directly to the mixing chamber.

If all heat transfer particle fractions have a particle size below the maximum particle sizes of the pyrolysis coke, magnetic separation devices in combination with magnetic heat transfer particles or exclusively one or more rotary screens connected in series are preferred 16 the aforementioned type instead of an adjustable sieve 34 , From these, the pyrolysis coke is then fed to the mixing chamber.

The derivation for fluidic pyrolysis products 7 serves for the withdrawal of the fluidic partial stream of material from the pyrolysis reactor 1 to a capacitor 23 , preferably a membrane separation device for a liquid / gas separation. In this there is a separation of the liquid and gaseous pyrolysis, the pyrolysis of the pyrolysis gas. The temperature of the fluidic pyrolysis products is to avoid evaporation effects, which could interfere with a reliable separation to choose below the boiling temperature of the pyrolysis condensate, preferably between 30 and 90 ° C, preferably between 40 and 80 ° C, more preferably between 50 and set 70 ° C.

The pyrolysis gas leaves the condenser via a gas line 24 and is either another use such. B. a Kreisgasauskopplung 26 supplied and / or for the energy supply of the pyrolysis system, ie for combustion as a fuel flow 25 for the burners 11 and 20 diverted.

The pyrolysis condensate is in turn from the condenser 23 via a condensate line 27 into the mixing chamber 28 where it is mixed with the pyrolysis coke to a suspension, the so-called. Slurry and as Slurrystrom 29 a forwarding (transport or storage) is forwarded to a subsequent preferred entrainment gasification.

The pyrolysis takes place in the pyrolysis reactor 1 instead, which is preferably arranged horizontally at least but at most 10 ° inclined to the horizontal (see. 1 and 2 ). On the other hand serves the heating 3 , in which no significant chemical reaction (possibly the combustion) is to take place, the bridging of a difference in height from the collecting container 18 for supplying heat transfer particles 5 for the heat transfer body. Consequently, the heat transfer particles bridge a slope as they pass through the heating path; the heating path has a corresponding inclination to the horizontal, preferably between 10 and 60 °, more preferably between 20 and 50 °, more preferably between 30 and 40 °. If the space conditions allow it and the aforementioned inclination is not too large, the two collection can be 18 and 22 gem. 3 also to a collection container 18 gem. 4 summarized, wherein the location of this common collecting container according to the second collection. 1 to 3 equivalent. A transport unit 17 would then no longer necessary, but the heating has a higher inclination to the horizontal.

1

pyrolysis reactor

2

Auger of the pyrolysis reactor

3

heating-up

4

Auger the heating section

5

Feed for heat transfer particles

6

Feed for feedstocks

7

derivation for fluidic pyrolysis

8th

derivation for solid pyrolysis

9

conveying direction

10

Heat transfer particles

11

burner

12

solid Material partial flow

13

first Heat transfer particle fraction

14

pyrolysis coke

15

Not separated part of the partial material flow

16

rotary screen

17

transport unit

18

Clippings

19

second Heat transfer particle fraction

20

burner in the collection container

21

Combustion air supply

22

second Clippings

23

capacitor

24

gas pipe

25

fuel flow

26

Cycle gas extraction

27

condensate line

28

mixing chamber

29

Slurrystrom

30

direction of rotation the screw conveyor in the heating section

31

direction of rotation the screw conveyor in the pyrolysis reactor

32

fluidic Material partial flow

33

lambda probe

34

scree

Claims (14)

A pyrolysis system for carbonaceous feedstocks, comprising a) a pyrolysis reactor ( 1 ), b) a heating line ( 3 ) for heat transfer particles ( 10 ) and c) a closed loop of heat transfer particles ( 10 ) through the pyrolysis reactor and the heating line, wherein, d) the heating section burner ( 11 . 20 ), wherein the burners are heatable with pyrolysis gas and e) low-oxygen exhaust gases from the combustion in the pyrolysis reactor ( 3 ) can be introduced and in this form a low-oxygen pyrolysis atmosphere, characterized in that f) the heating section forced conveying means for the heat transfer particles ( 10 ) having. A pyrolysis system according to claim 1, wherein the heating section ( 3 ) a screw conveyor ( 4 ) as compulsory conveying means. Pyrolysis system according to claim 1 or 2, wherein the heating section ( 3 ) is formed by a volume in a housing, wherein at least one burner ( 11 ) opens into the volume. Pyrolysis system according to one of the preceding claims, wherein the heating section ( 3 ) via a gas-tight feed for heat transfer particles ( 10 ) into the pyrolysis reactor ( 1 ). A pyrolysis system according to claim 4, wherein the feed is a lambda probe ( 33 ) for detecting the oxygen content in the feed. A pyrolysis system according to claim 5, comprising a control unit for the burners ( 11 . 20 ) using the oxygen content. A pyrolysis system according to any one of the preceding claims, wherein the pyrolysis reactor is one each for a heat transfer particle feed ( 5 ) and feedstocks ( 6 ), one derivation each for fluidic and solid pyrolysis products ( 7 respectively. 8th ) and funding ( 2 ) for the heat transfer particles ( 10 ) and the starting materials. Pyrolysis system according to one of claims 2 to 7, wherein the conveying means ( 2 . 4 ) in the pyrolysis reactor ( 1 ) and in the heating section ( 3 ) each comprise at least one rotatable screw conveyor. Pyrolysis system according to one of the preceding claims, wherein between pyrolysis reactor ( 1 ) and heating line ( 3 ) at least one separating device ( 16 . 34 ) is provided for separating heat transfer particles and solid pyrolysis products. A pyrolysis system according to claim 9, wherein the separators are a sieve ( 34 ). A pyrolysis system according to claim 9 or 10, wherein the sieve ( 34 ) has an adjustable mesh size. A pyrolysis system according to any one of claims 9 to 11, wherein the heat transfer particles ( 10 ) at least two different heat transfer particle fractions in size and / or material composition ( 13 . 19 ) and dividing device ( 16 . 34 ) comprises a sieve or other separating device for each heat transfer particle fraction. Pyrolysis system according to one of claims 9 to 12, wherein the separator is a magnetic deposition device for magnetic Heat transfer particles includes. Pyrolysis system according to one of the preceding claims, wherein a capacitor for the separation of fluidic pyrolysis products in pyrolysis condensate and pyrolysis gas is provided, wherein the pyrolysis gas of the combustion supplied is.