FI129404B

FI129404B - Process for the manufacture of a lignin component, lignin component and its use and product

Info

Publication number: FI129404B
Application number: FI20116253A
Authority: FI
Inventors: Mauno Miettinen
Original assignee: Upm Kymmene Corp
Priority date: 2011-12-09
Filing date: 2011-12-09
Publication date: 2022-01-31
Also published as: FI20116253A7; FI20116253L

Abstract

Keksintö koskee menetelmää ligniinikomponentin valmistamiseksi ligniinimateriaalista happokäsittelyllä, joka menetelmä käsittää: ligniinikomponentin muodostamisen ligniinimateriaalista käsittelemällä ligniinimateriaalia vähintään yhdessä happokäsittelyvaiheessa; ja tuhkan ja/tai hiilihydraattien vähentämisen ligniinikomponentissa optimoimalla vähintään yhtä happokäsittelyvaihetta prosessiparametrien kombinaation avulla, joka käsittää viipymäajan, lämpötilan ja pH-tason. Lisäksi keksintö koskee vastaavaa ligniinikomponenttia, ligniinikomponentin käyttöä ja tuotetta.The invention relates to a method for producing a lignin component from a lignin material by acid treatment, the method comprising: forming a lignin component from the lignin material by treating the lignin material in at least one acid treatment step; and reducing the ash and / or carbohydrates in the lignin component by optimizing the at least one acid treatment step by a combination of process parameters comprising a residence time, temperature and pH level. The invention further relates to a corresponding lignin component, the use of a lignin component and a product.

Description

A METHOD FOR MAKING A LIGNIN COMPONENT, A LIGNIN COMPONENT AND ITS USE AND A PRODUCT

FIELD OF THE INVENTION The invention relates to a method for manu- facturing a lignin component. Further, the invention relates to a lignin component and a use of the lignin component. Further, the invention relates to a prod- uct.

BACKGROUND OF THE INVENTION Known from publication WO 2006/031175 is a method for separation of lignin from black liquor. From WO 2009028969, US 2003156970, US 2011297340, EP 0364632 and US 2004244925 are known different methods for making a lignin product.

OBJECTIVE OF THE INVENTION The objective of the invention is to disclose a new method for manufacturing a lignin component. An- other objective of the invention is to produce a lig- nin component with improved properties and a product comprising the lignin component.

SUMMARY OF THE INVENTION O The method for making a lignin component from A a lignin material according to the present invention N is characterized by what is presented in claim 1. N The lignin component according to the present

I T 30 invention is characterized by what is presented in 0 claim 21. Lo S The use of the lignin component according to 5 the present invention is characterized by what is pre- N sented in claim 22.

The product according to the present inven- tion is characterized by what is presented in claim

23.

BRIEF DESCRIPTION OF THE FIGURES The accompanying figures, which are included to provide a further understanding of the invention and constitutes a part of this specification, illus- trate some embodiments of the invention and together with the description help to explain the principles of the invention. In the figures: Fig. 1 is a flow chart illustration of a method according to one embodiment of the present in- vention, Fig. 2 is a flow chart illustration of a method according to another embodiment of the present invention, Fig. 3 is a flow chart illustration of a method according to another embodiment of the present invention, Fig 4 is a flow chart illustration of a meth- od according to another embodiment of the present in- vention, Fig. 5a and 5d show lignin structures in cakes of comparative lignin components, and — Fig. 5b and 5c show lignin structures in O cakes of lignin components according to the present a invention. n 30

DETAILED DESCRIPTION OF THE INVENTION i A In the method of the present invention a lig- © nin component is made from a lignin material (1) by a = 35 mild acid treatment. According to the invention, a N lignin component (3) is formed of lignin material so that the lignin material (1) is treated in at least one acid treatment stage (2a,2b) and the at least one acid treatment stage is optimized by means of a combi- nation of process parameters comprising retention time, e.g. long retention time, temperature, e.g. high temperature, and pH level, e.g. sufficient low, in or- der to decrease ash and/or carbohydrates in the lignin component, and preferably in order to remove undesired substance from the lignin component and to purify the lignin component.

One embodiment of the method of the present invention is shown in figure 1. Another embodiment of the method of the present invention is shown in figure

2. Another embodiment of the method of the present in- vention is shown in figure 3. Another embodiment of the method of the present invention is shown in figure 4.

The invention is specially based on improving properties of the lignin component. When the lignin ma- terial is acid treated at one or more acid treatment stage by optimizing retention time, temperature and pH level, then the properties, such as purity, dry solids content, filterability, amounts of carbohydrates and ash, of the lignin component can be improved. Further, odour in the lignin component can be decreased. Then it is provided the lignin component which is suitable to use in typical and special applications.

— In this context, a lignin material refers any O material or composition containing lignin. The lignin AN material may contain one or more material components. N 30 In one embodiment suitable and desired additives can - be added into the lignin material to form a desired = lignin component.

A In one embodiment the lignin material in- © cludes material which is selected from a group con- = 35 sisting of lignin from alkaline pulping process, kraft N lignin, lignin from soda process, lignin coming from a process in which lignin 1s separated the raw material by a solution including suitable chemicals and their combinations. In one embodiment the lignin material in- cludes flash precipitated lignin. In one embodiment flash precipitated lignin is obtained after (Co, precipitation. Preferably, flash precipitated lignin is formed as disclosed in patent application PCT/FI2011/050896.

In one embodiment the lignin is precipitated from the black liquor by a continuous process with CO; at 3 - 8 bar overpressure. In one embodiment the lig- nin is separated by a flash precipitation lignin sepa- ration method, such as disclosed in patent application PCT/FI2011/050896. In one embodiment of the present invention the lignin is flash precipitated lignin. The term “flash precipitated lignin” should be understood in this specification as lignin that has been precipi- tated from black liquor in a continuous process by de- creasing the pH of a black liquor flow, under the in- fluence of an over pressure of 200 - 1000 kPa, down to the precipitation level of lignin using a carbon diox- ide based acidifying agent, preferably carbon dioxide, and by suddenly releasing the pressure for precipitat- ing lignin. The residence time in the above method is under 300 s. The flash precipitated lignin particles, — having a particle diameter of less than 2 pm, form ag- O glomerates, which can be separated from black liquor AN using e.g. filtration. The flash precipitated lignin N 30 can be purified and/or activated if needed for the N further processing. The flash precipitated lignin has = many advantages, e.g. activity, dispersability, solu- A bility, drainability and preservability. In one embod- © iment of the present invention, the lignin component = 35 is a flash precipitated kraft lignin. Preferably, the N flash precipitated kraft lignin is undrained. There-

fore the lignin has higher activity, and the lignin can be re-dissolved. The lignin needs only a very sim- ple re-dispersing stage when it is added e.g. into an adhesive mixture. Also control of the amount of water 5 in the lignin based composition is easier when the re- dispersing is easier. Further, the lignin is easier to handle in the process because the lignin is not dusty. Preferably, the flash precipitated kraft lignin has dry matter content of 50 -— 80 %.

In one embodiment the lignin material is treated chemically and/or mechanically before the at least one acid treatment stage of the present inven- tion. In one embodiment the lignin material is precip- itated before the at least one acid treatment stage.

In one embodiment the lignin material is re-slurried before the at least one acid treatment.

In this context, a lignin component means product formed from lignin material in at one or more stages. Term “lignin component” is already used after the first treatment stage.

In this context, a carbohydrate refers any carbohydrates, especially hemicellulose.

In one embodiment the at least one acid treatment stage is acid washing (2a). In the acid washing an amount of ash can be decreased in the lig- nin component. Further, in the acid washing filtera- — bility of the lignin component can be enhanced. Fur- O ther, in the acid washing dry solids content of the AN lignin component can be improved. Improved dry solid N 30 content of filter cake leads to lower energy consump- N tion in drying and to lower consumption of water in = washing to reach same purity. Also dryer can be small- A er, which leads to savings in investment. Savings in © water consumption is important, since likely washing = 35 water must be circulated back to evaporation plant. N Also certain dry solid content is needed to maintain processability of lignin cakes. For applications re- quiring no drying, for example burning, the low con- tent of water in filter cake is a benefit.

In one embodiment the at least one acid treatment stage is acid hydrolysis (2b). In the acid hydrolysis an amount of carbohydrates can be decreased in the lignin component. Further, in the acid hydroly- sis an amount of ash can be still decreased in the lignin component. It is important that lignin softens before or during acid hydrolysis; then carbohydrates can be removed from the lignin component and the lig- nin component can be purified. The softening is pref- erably performed slowly in correct temperature to pre- vent condensation of lignin and formation of char. The softening can be carried out at wide pH range.

In one embodiment the lignin material (1) is treated at two acid treatment stages in which first stage is acid washing (2a) and second stage is acid hydrolysis (2b). The first stage can be a typical acid washing. Preferably, the second stage is a purifica- tion stage.

In this context, the acid washing refers to any acid washing method. In one embodiment the acid washing is performed with HS50,4, other acid or other suitable acidifying chemical. The optimization of the invention affects positively consumption of HSO. or — other acid or other acidifying chemical. O In this context, the acid hydrolysis refers AN to any acid hydrolysis method. In one embodiment the N 30 acid hydrolysis is performed by means of H2S504, or oth- N er suitable acidifying chemical, typically in the = presence of water. A In one embodiment the lignin material is © treated in the at least one acid treatment stage with = 35 H2S04.

N

In one embodiment the method comprises two ac- id treatment method steps. In one embodiment the first step is a removal of ash and the second step is a re- moval of carbohydrates. In one embodiment the first step is a increasing of dry solids content in the lig- nin component and the second step is a removal of car- bohydrates from the lignin component. In one embodiment the first step comprises a removal of ash and increas- ing of dry solids content in the lignin component, and the second step is a removal of carbohydrates from the lignin component.

In one embodiment the method comprises a pre- treatment step before the at least one acid treatment stage. In one embodiment the lignin material is re- slurried in the pre-treatment step. In a preferred em- bodiment the pre-treatment step is a softening step of lignin in which the lignin is softened and structure of the lignin is modified. An acid is able to hydrolyze carbohydrates in lignin after the softening step.

Preferably, in each acid treatment stage of the invention a suitable combination of temperature, retention time and pH level is selected. The selected combination varies based on acid washing or acid hy- drolysis. The process conditions are selected such that lignin does not alternate into carbon or char during the acid treatment.

— Preferably, long retention time is used in O the acid treatment according to the invention. In one AN embodiment the retention time is over 1 hour. In one N 30 embodiment the retention time is over 4 hours, prefer- N ably over 6 hours, and more preferable over 8 hours. E: In one embodiment the retention time is over 16 hours. A In this context, retention time means time of © the treatment stage. The retention time does not in- 3 35 clude a filtration time.

In one embodiment the temperature is over 60 °C during the treatment stage. In one embodiment the temperature is over 70 °C, preferably over 72 °C, more preferable over 73 °C, and most preferable over 75 °C. In a preferred embodiment pH level is suffi- cient low during the treatment stage. In one embodi- ment the pH level is under 3.5, preferable between 2 -

3. In one embodiment the pH level is under 2.0, pref- erably between 0.5 - 1.5. In one embodiment the pH level which is between 2 - 4 can be used. In one embodiment the pH level is between 0.5 - 4.0, preferably 0.8 — 1.5, the temperature is be- tween 80 — 130 °C, preferably 80 — 105 °C, and the re- tention time is between 2 - 60 hours, preferably 6 - 30 hours, at the at least one acid treatment stage, e.g. at the acid hydrolysis stage. Temperature is be- low glass transition point of lignin. In one embodiment the pH is between 2.5 -

3.5, temperature is between 65 — 80 °C, preferably be- tween 70 - 80 °C and more preferable about 70 °C, and retention time is over 1 hour at the acid washing stage. Increasing temperature and/or retention time and/or decreasing pH level dry solid content and fil- terability may be improved. In one embodiment the lignin material is treated in the at least one acid treatment stage and — the at least one acid treatment stage is optimized by O means of process parameters selected from retention N time, temperature, pH level, mixing, oxidizing and N 30 their combinations. In one embodiment combination of - selected process parameters is optimized in the at & least one acid treatment stage. In one embodiment com- A bination of selected process parameters is optimized © in each acid treatment stage. = 35 In one embodiment the acid treatment stage is N adjusted by means of process parameters in order to increase low molecular weight lignin fragments. If harsh reaction conditions, e.g. temperature over 70 *C, retention time over 8 hours and pH level between 1 = 1.5, is applied in the acid hydrolysis then low mo- lecular weight lignin can be obtained with improved yield.

In one embodiment, when the pre-treatment is made before the acid treatment so in the pre-treatment retention time is below 2 hours, temperature is be- tween 55 - 70 C and pH is between 9 - 10.5. In one embodiment, when the pre-treatment is made before the acid treatment so in the pre-treatment retention time is below 2 hours, temperature is between 55 - 75 °C and pH is between 9 - 10, and in the acid treatment retention time is over 8 hours, temperature is between 70 - 80 C and pH is below 3.5. In an alternative em- bodiment, when the pre-treatment is made before the acid treatment so in the pre-treatment retention time is over 8 hours, temperature is between 60 - 75 °C and pH is between 9 - 10, and in the acid treatment reten- tion time is below 2 hours, temperature is between 65 - 80 ”C and pH is below 3.5.

It is important for the invention that long retention time is used at least in one stage. Alterna- tively, the long retention time can be used in more than one stage. The long retention time can be used at — the acid treatment stage, e.g. in the acid washing O and/or in the acid hydrolysis, and/or in the pre- N treatment step.

N 30 In one embodiment the formed lignin component - (3) is filtrated at the filtration stage (4a,4b) after a. at least the latest acid treatment stage (2a,2b). In A one embodiment the formed lignin component is filtrat- © ed after each of the at least one acid treatment stag- 3 35 es.

In this context, the filtration refers to any filtration method which can be used in the filtration of the lignin. Preferably, in the filtration the lig- nin component is washed by water and pressed and op- tionally air-dried. The filtration can be performed by any suitable filtration device. In one embodiment the formed lignin component is filtrated by pressure filtration or vacuum filtration. In one embodiment pressure is between 10 - 20 bar, preferably 13 — 17 bar and more preferable about 15 bar in the pressure filtration.

Preferably improved filterability, especially better filtration rate, achieved by means of the opti- mization leads to smaller pressure requirement in the filtration and to shorter filtration time. Then cheaper filters, e.g. based on size and type of device, may be used.

In one embodiment the pH level is adjusted just before the filtration, especially if shorter re- tention time is used in the acid treatment stage.

In one embodiment temperature is over 50 % and pH is between 2 to 4 during the filtration.

In one embodiment the lignin material is treated in the at least one acid treatment stage such that dry solids content of the lignin component can be increased over 5 %, preferably 5 - 15 %, more prefera- — ble about 10 - 15 3, as compared with standard lignin O component formed by a known acid washing method. In AN one embodiment dry solids content of the lignin compo- N 30 nent is over 60 %, preferably over 70 %, more prefera- N ble between 70 — 90 % and most preferable between 70 - E: 80 %. A In one embodiment the lignin material is © treated in the at least one acid treatment stage such 3 35 that carbohydrates content of the lignin component is under 1.0 %, preferably under 0.5 3, more preferable under 0.2 % and most preferable under 0.1 %.

In one embodiment the lignin material is treated in the at least one acid treatment stage such that ash content of the lignin component is under 1.0 %, preferably under 0.5 %, more preferable under 0.2 3 and most preferable under 0.1 3.

In one embodiment proportion of lignin dis- solved during the at least one acid treatment stage is adjusted by means of process parameters selected from retention time, temperature, pH level, mixing effi- ciency, mixer type, oxidation and their combinations.

Then low molecular weight lignin component can be achieved. In one embodiment proportion of lignin dis- solved is adjusted during the acid hydrolysis stage.

In one embodiment the additional oxidation is made after the filtration in which an acidic filtrate is additionally oxidized.

In one embodiment the lignin component is ad- ditionally oxidized during the acid treatment stage, e.g. at the acid hydrolysis stage. The additional oxi- dation may be performed by means of air, oxygen, other oxidizing agent or their combinations in order to sta- bilize structure of the lignin component, to increase purity of lignin and to remove odour.

The lignin component (3) obtainable by the method of the present invention can be used as compo- N nent in manufacturing a final product selected from N activated carbon, carbon fiber, lignin composite, e.g. N 30 lignin-plastic composite or lignin-fiber composite, N binder material, phenolic component, dispersion agent z and their combinations.

© The final product or product comprises the S lignin component of the present invention. Preferably, = 35 pure lignin component according to the present inven- N tion is needed in the manufacturing of the activated carbon and carbon fibers.

The method according to the present invention provides the lignin component with good quality. When improving the purify and increasing dry solids content of the lignin component so then it may be provided better properties of the lignin component and the fi- nal product.

The present invention provides an industrial- ly applicable, simple and affordable way of making the lignin component from the lignin material. The method according to the present invention is easy and simple to realize as a production process. The method accord- ing to the present invention is suitable for use in the manufacture of the different lignin components from different lignin materials.

EXAMPLES The invention is described in more detail by the following examples with reference to accompanying figures 1 - 4 and ba-d.

Example 1 In this example and in figure 1, a lignin component (3) is formed by an acid treatment.

A starting lignin material (1), which is flash precipitated lignin, is treated by two acid treatment stages (2a, 2b). The first stage (2a) is an N acid washing stage and the second stage (2b) is an ac- N id hydrolysis stage. Process conditions are following = at the first stage: temperature about 70 °C, retention N 30 time over 1 hour and pH level about 3. The acid wash- E ing is performed with H,S0,. Process conditions are n following at the second stage: temperature over 70 °C, A retention time over 8 hours and pH level between 1 - — 1.5. The acid treating in hydrolysis is performed with a 35 H2S04.

The lignin component (3) is filtrated after each acid treatment stage (2a,2b) by pressure filtra- tion (4a,4b). Temperature is over 50 °C and pH is about 2 to 4 during the filtration.

The lignin component can be additionally oxi- dized during the acid treatment stage.

In these tests it was discovered that it may be produced the lignin component with excellent prop- erties. The formed lignin component has low ash and carbohydrates contents. It was discovered that the ash content can be reduced during the first stage. Fur- ther, the ash content can be still reduced during the second stage. It was discovered that the carbohydrates content can be mainly reduced during the second stage but a part of carbohydrates can be reduced during the first stage. By means of high temperature, long reten- tion time and low pH lignin is softened. After soften- ing, acid is able to hydrolyze carbohydrates and oxi- dize accessible part of lignin into soluble compounds.

Carbohydrates may be removed during the acid treat- ment.

Further, it was discovered that dry solids content of the final lignin component cake can be in- creased and filterability can be enhanced already at the first stage. Dry solids content of the lignin com- ponent can be increased over 5 % as compared with — standard lignin component. The lignin component has O ash content below 0.1 % and carbohydrates content be- AN low 0.2 %. Further, at least part of inorganic sulphu- N 30 re was removed at the acid hydrolysis stage. Further, N by means of acid hydrolysis may be increased glass = transition temperature of lignin and/or decomposition 2 temperature of lignin.

Further, in these tests it was discovered that the special good optimization results were achieved by two stages process. Example 2 In this example and in figure 2 a lignin com- ponent (3) is formed by an acid treatment.

A starting lignin material (1) is treated by one acid treatment stage which 1s an acid washing stage (2a). Process conditions are following: tempera- ture is about 70 °C, retention time over 1 hour and pH level is about 3. The acid washing is performed with H2S04.

The lignin component (3) is filtrated after acid washing by pressure filtration (4a). Temperature is over 50 °C and pH is about 2 to 4 during the fil- tration.

In these tests it was discovered that the formed lignin component has low ash content but carbo- hydrates content has not decreased, such as in example

1. It was discovered that the ash content can be re- duced during the acid washing.

Example 3 — In this example and in figure 3, a lignin O component (3) is formed by an acid treatment.

A A starting lignin material (1) is treated by N 30 one acid treatment stage which is an acid hydrolysis N (2b). Process conditions are following: temperature E over 70 °C, retention time over 8 hours and pH level a between 1 - 1.5.

O The lignin component (3) is filtrated after = 35 acid hydrolysis by pressure filtration (4b). Tempera- N ture is over 50 °C during the filtration.

In these tests it was discovered that it may be produced the lignin component with good properties. The formed lignin component has low ash and carbohy- drates contents. It was discovered that the ash con- tent and carbohydrates content can be reduced during the acid hydrolysis. Example 4 In this example and figure 4, a lignin compo- nent (3) is formed by an acid treatment.

A starting lignin material (1) is treated firstly at a pre-treatment stage (5) in which is made a re-slurry step, and secondly at an acid washing stage (2a) in order to produce a lignin component. Af- ter the acid washing the lignin component is filtrated (da).

In the tests 1 - 4 the pre-treatment is car- ried out so that short retention time and high pH are used. Then, in the acid washing long retention time and low pH are used.

In the tests 5 and 6 the pre-treatment is carried out so that long retention time and high pH are used. In the acid washing shorter retention time and low pH, about 2.5, are used. It was discovered that during the pre-treatment of tests 5 and 6 soften- ing and particle growth of the lignin is happened — thanks to long retention time. Therefore, shorter re- O tention time is sufficient in the acid washing.

N N 30 Process conditions are described in table 1.

N = a

O

O 3 35

Table 1 Test T5, t5, T2a, t2a, Tfilt, | pH during | Average ‘C h °C h ‘C long re- | cake tention dry matter, i Jeo ja Jeo [10 Jeo Jz.s lass | 2 Jes ja [77 [13 Jeo jos [ma | 8 [73 [17 Jeo |i [so [o.s [72.7 | Je les Jas los (ja. fos jos — Jess | in which T5 is temperature of the pre-treatment t5 is retention time of the pre-treatment T2a is temperature of the acid washing t2a is retention time of the acid washing Tfilt is temperature of the filtration In these tests it was discovered that it may be produced the lignin component with good cake dry matter.

In tests 1 - 4 it was discovered that the cake dry matter can be increased when the temperature of the acid washing was over 70 °C, retention time of the acid washing was long and pH was low, about 2.5. 5 Further, in tests 5 —- 6 it was discovered a that the cake dry matter can be increased when the N temperature of the pre-treatment was over 70 °C and N retention time of the pre-treatment was long. x 20 It was discovered that it is important for E the invention that long retention time and temperature O over 70 °C are used in at least one acid treatment © stage. > Two lignin components of the present inven- tion have been shown in figures 5b (Test 2) and 5c

(Test 5) (SEM images). By way of comparison figures ba (Test 1) and 5d (Test 6) (SEM images) show structures of comparative lignin components. Improvements in fil- terability and cake dry matter between Test 1 and Test 6 is mainly due to enhanced agglomeration. Improvement in cake dry matter between Test 6 and Tests 2 - 5 is due to softening of lignin and re-structure into big- ger single particles. Example 5 In this example and figure 2, a lignin compo- nent (3) is formed by an acid treatment.

A starting lignin material (1) is fre- slurried, and after then the lignin is treated at an acid treatment stage (2a) in order to produce a lignin component. After the acid treatment the lignin compo- nent is filtrated (4a).

Delay between the re-slurry and the acid treatment is about 1 hour and temperature is about 60 — 65 C.

Process conditions of the acid treatment are described in table 2. In the tests 3 - 4 the acid treatment is carried out so that long retention time and low pH are used. Tests 1 and 2 are comparative tests. In test 1 low temperature and short retention time are used. In test 2 low temperature and long re- — tention time are used.

S

N n 30 = a

O

O 3 35

Table 2 Test | T2a, | t2a, | Tfilt, | pH Average ‘C h ‘C cake dry matter, a Jeo [a Jeo [2.5 Jans | 2 leo [10 Jeo [2.5 [47.5 | 3 [27 [13 Jeo [2.5 [5.8 | in which T2a is temperature of the acid treatment t2a is retention time of the acid treatment Tfilt is temperature of the filtration In these tests it was discovered that it may be produced the lignin component with good cake dry matter.

In tests 1 - 4 it was discovered that the cake dry matter can be increased when the temperature of the acid treatment was over 70 °C, retention time of the acid treatment was long and pH was low, about 2.5. Example 6 In this example and figure 1, a lignin compo- nent (3) is formed by two stage acid treatment. = A starting lignin material (1) is re- < slurried, and after that the lignin is treated at two- N 20 stage acid treatment (2a, 2b) in order to produce a N lignin component.

The first acid treatment stage in - this example is test 5 in Table 1. The first stage is E an acid washing and the second stage is an acid hy- 2 drolysis.

After each acid treatment stages the lignin O 25 component is filtrated (4a, 4b). > Lignin cake from the acid washing stage was re-slurried for 1 hour at 60 —- 70 °C.

The pH of the lignin slurry was adjusted just before the acid hy- drolysis stage. Process conditions of the acid hydrolysis are described in table 3.

Table 3 Test | T2b, | t2b, | pH 700 °C | Carbo- Mw, Acid ‘C h ash of | hydrates, | g/mol | used, lignin, | % dry kg/t % dry lignin 2 [120 [2 [3.6]0.00 [0.37 — [sia jo | 2 leo [1 |[2.0]0.00 [0.60 [4180 [13 | 3 los [1 [1.s]0.00 Jo.z [4200 [25 | a los [a [1.5[0.09 Joao [aso | | 5 — [105 [16 [1.5]0.05 —|[<o.o2 [sea | | 6 leo [a [1.0]0.33 Jos [4340 [150 | 7 leo [17 [1.0]0.09 [0.09 — [4000 | — | le leo |2 ([o.slo.os [0.29 — |asso [540 | in which T2b is temperature of the acid hydrolysis t2b is retention time of the acid hydrolysis Tfilt is temperature of the filtration Test 9 with T2b of 140 °C, t2b of 1 hour and pH of 3.5 resulted in the formation of char, which ad- N 15 hered to reactor walls. N In these tests it was discovered that it may N be produced the lignin component with good ash content N and carbohydrates content. Starting lignin material I for the hydrolysis tests, so Test 5 in Table 1 had E 20 carbohydrates content of 0.73 %. In tests it was dis- O covered that the ash and carbohydrates content can be © decreased when the temperature of the acid hydrolysis > was high, over 75 °C, retention time of the acid hy- drolysis was long and pH was low. Long retention time in the acid washing stage shortens the time needed in the acid hydrolysis stage. Molecular weight of the lignin after the acid hydrolysis reveals that exten- sive condensation was not encountered. The consumption of sulphuric acid increases rapidly when pH is below

1.

The method according to the present invention is suitable in different embodiments to be used for making the most different kinds of lignin components from different lignin materials. The lignin component according to the present invention is suitable in dif- ferent embodiments to be used in different final prod- ucts.

The invention is not limited merely to the example referred to above; instead many variations are possible within the scope of the inventive idea de- fined by the claims.

N O N N PP N

I jami a 0

LO N

O Oo

N

Claims

1. A method for making a lignin component from a lignin material by an acid treatment, the meth- od comprising: - forming the lignin component from the said lignin material by treating the lignin material in at least one acid treatment stage so that at least one acid treatment stage is an acid washing; and - optimizing the said at least one acid treatment stage by means of a combination comprising a re- tention time of over 6 hours, a temperature of over 70 °C and a pH level of less than 3.5 in the acid treatment stage; and - filtrating the acid treated lignin material after each acid treatment stage, in order to decrease ash and carbohydrates in the lignin component.

2. The method according to claim 1, wherein at least one acid treatment stage is an acid hydroly- sis.

3. The method according to claim 1 or 2, wherein the method comprising: treating the lignin ma- terial in two acid treatment stages in which the first stage is acid washing and the second stage is acid hy- drolysis. -

4. The method according to any one of claims O 1 to 3, wherein the method comprising: treating the N lignin material in the at least one acid treatment N 30 stage such that dry solids content of the lignin com- N ponent is increased over 5 % as compared with standard E lignin component. 0

5. The method according to any one of claims A 1 to 4, wherein the method comprising: treating the = 35 lignin material in the at least one acid treatment N stage such that carbohydrates content of the lignin component is under 0.2 %.

6. The method according to any one of claims 1 to 5, wherein the method comprising: precipitating the lignin material before the at least one acid treatment stage.

7. The method according to any one of claims 1 to 6, wherein the lignin material comprises material which is selected from a group consisting of lignin from alkaline pulping process, kraft lignin, lignin from soda process, lignin coming from a process in which lignin is separated from the raw material by a solution including suitable chemicals and their combi- nations.

8. The method according to any one of claims 1 to 7, wherein the lignin material comprises flash precipitated lignin.

9. The method according to any one of claims 1 to 8, wherein the method comprising: treating the lignin material in the at least one acid treatment stage with H2SO..

10. The method according to any one of claims 1 to 9, wherein the retention time is over 8 hours.

11. The method according to any one of claims 1 to 10, wherein the temperature is over 75 °C.

12. The method according to any one of claims 1 to 11, wherein the pH level is between 0.5 - 1.5.

13. The method according to any one of claims 1 to 12, wherein the pH level is between 0.5 - 4.0, N the temperature is between 80 - 130 C and the reten- N tion time is between 2 - 60 hours in at least one acid = 30 treatment stage. N

14. The method according to any one of claims Ek 1 to 13, wherein the method comprising: filtrating the * lignin component by pressure filtration or vacuum fil- O tration. = 35

15. The method according to any one of claims S 1 to 14, wherein the method comprising: adjusting the pH level just before the filtrating.

16. The method according to any one of claims 1 to 15, wherein the temperature is over 50 °C and the pH level is between 2 to 4 during the filtration.

17. The method according to any one of claims 1 to 16, wherein the method comprising: treating the lignin material in the at least one acid treatment stage; and optimizing the at least one acid treatment stage by means of process parameters selected from re- tention time, temperature, pH level, mixing, oxidizing and their combinations.

18. The method according to any one of claims lto 17, wherein the method comprising: adjusting pro- portion of lignin dissolved during the at least one acid treatment stage by means of process parameters selected from retention time, temperature, pH level, mixing efficiency, mixer type, oxidation and their combinations.

19. The method according to any one of claims 1 to 18, wherein the method comprising: additionally oxidizing the lignin component or acidic filtrate.

20. The method according to any one of claims 1 to 19, wherein the method comprises a pre-treatment step before the at least one acid treatment stage.

21. A lignin component formed of a lignin ma- terial by an acid treatment, wherein - the lignin component is formed from the lignin material by treating the lignin material in at N least one acid treatment stage so that at least N one acid treatment stage is an acid washing and a = 30 retention time of over 6 hours, a temperature of N over 70 °C and a pH level of less than 3.5 are =E used in the said acid treatment stage, and by * filtrating the acid treated lignin material after O each acid treatment stage in order to decrease = 35 ash and carbohydrates in the lignin component, S and

- the lignin component has decreased ash and carbo- hydrate contents, and the lignin component con- tains under 0.1 % of ash and under 0.1 % of car- bohydrates.

22. A use of the lignin component obtainable by the method of any one of claims 1 - 20, as compo- nent in manufacturing a final product selected from activated carbon, carbon fiber, lignin composite, binder material, phenolic component, dispersion agent and their combinations.

23. A product comprising the lignin component obtainable by the method of any one of claims 1 to 20.

24. The product according to claim 23, wherein the product is selected from activated carbon, carbon fiber, lignin composite, such as lignin-plastic composite and lignin-fiber composite, binder material, phenolic component, dispersion agent and their combi- nations.

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