Method of online control of a slag forming gasification process and plant for a gasification process

Patent metadata

Field	Value
Publication number	US-11499105-B2
Application number	US-202016845449-A
Country	US
Kind code	B2
Filing date	Apr 10, 2020
Priority date	Apr 15, 2019
Publication date	Nov 15, 2022
Grant date	Nov 15, 2022

Abstract

A method of online control of a slag-forming process of gasification of a carbonaceous solid fuel, especially coal, in a gasification reactor with supply of a gasifying agent and a moderator is provided. Certain embodiments relate to a gasification process for producing a product gas including carbon monoxide and hydrogen from a solid fuel, to a computer program for online control of the slag-forming gasification process, and to a plant for conducting a gasification process for producing a product gas including carbon monoxide and hydrogen from a solid fuel. Certain aspects of the invention combine an online solid fuel analysis with a process model in order to operate a gasification process for solid fuels by the feed-forward principle at the thermodynamically optimal operating point. The invention permits the establishment of the operating point in real time in order to react to rapid variations in the composition of the solid fuel. Certain embodiments also permit the complete automation of the gasification process.

First claim

The invention claimed is:

1. A method of online control of a slag-forming process of gasification of a carbonaceous solid fuel, in a gasification reactor with supply of a gasifying agent and a moderator, the method comprising the steps of:
a) defining the quantity of a product gas to be produced by the gasification process;
b) conducting an online solid fuel analysis on a solid fuel sample taken prior to entry of the solid fuel into the gasification reactor by means of an online solid fuel analyzer to determine an ash content and an ash composition of the solid fuel prior to entry into the gasification reactor;
c) reading out operating data of the gasification reactor by means of a process control system;
d) processing the data from the online solid fuel analysis and the operating data of the gasification reactor in a process model to ascertain an operating point of the gasification reactor while simultaneously achieving a product gas quantity defined, wherein the process model:
i. determines an operating temperature of the gasification reactor based on the ash composition ascertained by the online solid fuel analysis in order to enable essentially complete outflow of slag out of the gasification reactor, wherein the operating temperature corresponds to a calculated ash liquidus temperature;
ii. determines a required mass flow rate of solid fuel based on the ash content ascertained by the online solid fuel analysis; and
iii. determines a required mass flow rate of gasifying agent and moderator based on operating data of the gasification reactor; and

e) adjusting the operating point of the gasification reactor by means of the process control system for control of the gasification process.

2. The method according to claim 1 , wherein steps b) to e) are repeated continuously in order to continuously adjust the operating point of the gasification reactor depending on variations in the ash content and in the ash composition of the solid fuel over time.

3. The method according to claim 2 , wherein steps b) to e) are repeated at an interval of 10 seconds to 300 minutes.

4. The method according to claim 2 , wherein steps b) to e) are repeated at an interval of 1 minute to 60 minutes.

5. The method according to claim 2 , wherein steps b) to e) are repeated at an interval of 5 minutes to 10 minutes.

6. The method according to claim 1 , wherein the operating temperature of the gasification reactor is calculated on the basis of a thermodynamic model for determination of the ash liquidus temperature as a function of the ash composition.

7. The method according to claim 1 , wherein the operating temperature of the gasification reactor is calculated on the basis of an artificial neural network model for determination of the ash fluid temperature as a function of the ash composition, wherein the operating temperature is above the calculated ash fluid temperature.

8. The method according to claim 7 , wherein the operating temperature is 50 to 100 K above the calculated ash fluid temperature.

9. The method according to claim 1 , wherein the online solid fuel analysis in step b) is conducted with the aid of a method selected from the group consisting of:
(a) prompt gamma neutron activation analysis (PGNAA),
(b) laser induced breakdown spectroscopy (LIBS), and
(c) x-ray fluorescence analysis (XRF).

10. The method according to claim 1 , wherein the ash content and the ash composition are determined on the basis of typical oxidation ratios of the analysed elements that form inorganic compounds.

11. The method according to claim 1 , wherein the method comprises the determination of the organic content and the organic composition of the solid fuel and the determination of the water content of the solid fuel prior to entry into the gasification reactor, and the ash content, the ash composition, the organic content, the organic composition and the water content of the solid fuel are used in the process model to ascertain the overall composition of the solid fuel.

12. The method according to claim 11 , wherein the overall composition of the solid fuel is used to ascertain the net calorific value and/or the gross calorific value of the solid fuel.

13. The method according to claim 11 , wherein the organic content and the organic composition and/or the water content of the solid fuel are determined by means of the online solid fuel analyser in step b).

14. The method according to claim 1 , wherein the method comprises the determination of the bulk density of the solid fuel prior to entry into the gasification reactor.

15. The method according to claim 1 , wherein the method comprises the determination of the time interval between the taking of the solid fuel sample and the entry of the solid fuel represented by the solid fuel analysis into the gasification reactor in order to adjust the operating point ascertained in step d) at the time of entry of the solid fuel represented by the solid fuel analysis into the gasification reactor by means of the process control system in step e).

16. The method according to claim 1 , wherein the solid fuel is selected from an element from the group comprising coal, biomass, sewage sludge, refuse derived fuel and mineral-contaminated plastics.

17. The method according to claim 1 , wherein the solid fuel sample for conducting the online solid fuel analysis is provided in particulate form, preferably in dust form.

18. A computer program loaded into the memory of a computer for conducting step d) in the performance of the method according to claim 1 .

Assignees

• Air Liquide

Inventors

• Graebner Martin
• Baran Adrianna
• Oers Evrim
• Moench Hans-Peter

Classifications

• C10J2300/0903

  Feed preparation · CPC title

• C10J3/723 Primary

  Controlling or regulating the gasification process · CPC title

• C10J2300/06

  Modeling or simulation of processes · CPC title

• C10J2300/1612

  CO2-separation and sequestration, i.e. long time storage · CPC title

• C10J2300/0956

  Air or oxygen enriched air · CPC title