# US 10,308,887 B2 · Method for conducting a hydrothermal carbonization reaction

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- Number: US 10,308,887 B2
- Document ID: US10308887B2
- Status: Granted
- Kind: B2
- Application number: 15/596,577
- Filed: 2017-05-16
- Published: 2018-08-23
- Granted: 2019-06-04
- Earliest claimed: 2017-02-20
- Assignees: AVA Green Chemistry Development GmbH
- Applicants: AVA Green Chemistry Development GmbH
- Inventors: Stepan Nicolja Kusche
- Web page: https://patentgrep.com/patent/US10308887B2

## CPC

- C10L 9/086: {Hydrothermal carbonization}
- C10B 45/00: Other details
- C10B 49/02: with hot gases or vapours, e.g. hot gases obtained by partial combustion of the charge
- C10B 53/02: of cellulose-containing material (production of pyroligneous acid C10C5/00)
- C10L 5/447: {Carbonized vegetable substances, e.g. charcoal, or produced by hydrothermal carbonization of biomass}
- C10L 2290/06: Heat exchange, direct or indirect
- C10L 2290/148: of steam
- C10L 2290/24: Mixing, stirring of fuel components
- C10L 2290/48: Expanders, e.g. throttles or flash tanks
- C10L 2290/58: Control or regulation of the fuel preparation of upgrading process
- C10L 2290/60: Measuring or analysing fractions, components or impurities or process conditions during preparation or upgrading of a fuel
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02E 50/30: Fuel from waste, e.g. synthetic alcohol or diesel
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
- C10B: DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS (cracking oils C10G; underground gasification of minerals E21B43/295)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

During hydrothermal carbonization, biomass is converted to biocoal. The reaction yield depends on the reaction conditions, including duration of the carbonization reaction or time period within which the slurry composed of water and biomass remains in the reaction tank and is exposed to pressure and temperature. These conditions should be selected so that the greatest possible dry residue of carbonized material remains in the slurry. It has been shown that the dry residue amount changes during the carbonization reaction with a curve that is similar, to a great extent, to that of the slurry pH value. Because determining the dry residue is difficult during the ongoing reaction, but determining the pH value can be easy during the entire reaction period, the reaction is terminated at a maximum of the pH value corresponding to a maximum of the biocoal dry residue, to the greatest possible extent.

## Claims

### Claim 1

A method for conducting a hydrothermal carbonization reaction comprising:
(a) supplying biomass to a reaction tank;
(b) creating reaction conditions with regard to pressure and temperature required for allowing a hydrothermal carbonization reaction to take place by introduction of steam and maintaining the reaction conditions for a reaction period;
(c) forming a slurry during the reaction period from the steam and the biomass that are introduced;
(d) monitoring the slurry with regard to progression of pH value of the slurry; and
(e) terminating the hydrothermal carbonization reaction as soon as a determination is made that a maximum of the pH value has been reached.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the progression of the slurry is determined continuously or at discrete time intervals, using at least one measurement probe assigned to the reaction tank, and noted in a database, wherein a process controller compares a current pH value with preceding measurement values from an identical measurement series within the reaction period, and triggers a termination signal when a decrease in pH value that follows an increase phase occurs.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the at least one measurement probe is disposed close to a bottom of the reaction tank.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the progression of the slurry is determined continuously or at discrete time intervals, using at least one measurement probe assigned to a bypass of the reaction tank, and the pH values are noted in a database, wherein a process controller compares a current pH value with preceding measurement values from an identical measurement series within the reaction period, and triggers a termination signal when a decrease in pH value that follows an increase phase occurs.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the slurry is mixed in the reaction tank during the reaction period.

### Claim 6 (depends on 1)

The method according to claim 1, wherein measurement begins when the reaction conditions of hydrothermal carbonization, with regard to pressure and temperature, have been reached and biomass and steam have already been introduced into the reaction container.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the hydrothermal carbonization reaction is terminated by bringing the slurry out of the reaction tank into a cooling tank via pumping or pressure equalization.