Off-gas incinerator control

Patent metadata

Field	Value
Publication number	US-2019282991-A1
Application number	US-201716301884-A
Country	US
Kind code	A1
Filing date	May 4, 2017
Priority date	May 24, 2016
Publication date	Sep 19, 2019
Grant date	—

Abstract

A process provides for minimizing an amount of fuel gas utilized in an absorber off-gas incinerator and better control of emissions. The process provides for less temperature deviations in the absorber off-gas incinerator firebox and for less deviation in an amount of oxygen in the absorber off-gas incinerator stack gas.

First claim

What is claimed is:

1 . A process for operating an off-gas incinerator, the process comprising:
introducing a flow of a reactant stream into an ammoxidation reactor; determining an amount of hydrocarbon in the reactant stream and determining a feed rate of the reactant stream; conveying a reactor effluent from the ammoxidation reactor to an absorber; supplying an absorber off-gas from the absorber to an absorber off-gas incinerator; and supplying fuel gas and air to the absorber off-gas incinerator; wherein the absorber off-gas, fuel gas, and air are supplied to the absorber off-gas incinerator in amounts to maintain about 6 kg or less NO x in an absorber off-gas incinerator stack gas per ton acrylonitrile produced and about 3.5 kg or less non-methane hydrocarbon in absorber off-gas incinerator stack gas per ton acrylonitrile produced.

2 . The process of claim 1 wherein a temperature in the absorber off-gas incinerator is maintained within about 10° F. of the temperature set point of the absorber off-gas incinerator.

3 . The process of claim 1 wherein the hydrocarbon in the reactant stream is selected from the group consisting of propane, propylene, isobutene, isobutylene and mixtures thereof.

4 . The process of claim 3 wherein the hydrocarbon is propylene.

5 . The process of claim 1 wherein the process provides about 5 volume % or less oxygen in an absorber off-gas incinerator stack gas.

6 . The process of claim 1 wherein the process maintains about 3.5 kg or less CO in the absorber off-gas incinerator stack gas per ton acrylonitrile produced.

7 . The process of claim 2 wherein the absorber off-gas incinerator temperature set point is a minimum temperature necessary to achieve less than the required amounts of NO x , non-methane hydrocarbon, and/or CO in the absorber off-gas incinerator stack gas.

8 . A process for operating an off-gas incinerator, the process comprising:
introducing a flow of a reactant stream into an ammoxidation reactor; determining an amount of hydrocarbon in the reactant stream and determining a feed rate of the reactant stream; conveying a reactor effluent from the ammoxidation reactor to an absorber; supplying an absorber off-gas from the absorber to an absorber off-gas incinerator; and supplying fuel gas and air to the absorber off-gas incinerator; wherein the absorber off-gas, fuel gas, and air are supplied to the absorber off-gas incinerator in amounts to maintain a temperature in the off-gas incinerator within about 10° F. of a temperature set point of the off-gas incinerator.

9 . The process of claim 8 wherein the temperature in the off-gas incinerator is maintained within about 5° F. of the temperature set point of the off-gas incinerator.

10 . The process of claim 8 wherein the hydrocarbon in the reactant stream is selected from the group consisting of propane, propylene, isobutene, isobutylene and mixtures thereof.

11 . The process of claim 10 wherein the hydrocarbon is propylene.

12 . The process of claim 8 wherein the process provides about 5 volume % or less oxygen in an absorber off-gas incinerator stack gas.

13 . The process of claim 8 wherein the process maintains about 6 kg or less NO x in the absorber off-gas incinerator stack gas per ton acrylonitrile produced.

14 . The process of claim 8 wherein the process maintains about 3.5 kg or less non-methane hydrocarbon in absorber off-gas incinerator stack gas per ton acrylonitrile produced.

15 . The process of claim 8 wherein the process maintains about 3.5 kg or less CO in the absorber off-gas incinerator stack gas per ton acrylonitrile produced.

16 . The process of claim 8 wherein the ammoxidation reactor has a propylene conversion rate of about 95 to less than about 100%.

17 . The process of claim 8 wherein the reactor effluent from the ammoxidation reactor is conveyed to a quench column and a quench column effluent having a temperature of about 65° C. to about 85° C. is conveyed to the absorber.

18 . The process of claim 8 wherein absorber off-gas has about 5 weight % or less water.

19 . The process of claim 8 wherein the absorber off-gas incinerator temperature set point is a minimum temperature necessary to achieve less than required amounts of NO x , non-methane hydrocarbon, and/or CO in the absorber off-gas incinerator stack gas.

20 . A process for operating an off-gas incinerator, the process comprising:
introducing a flow of a reactant stream into an ammoxidation reactor; determining an amount of hydrocarbon in the reactant stream and determining a feed rate of the reactant stream; conveying a reactor effluent from the ammoxidation reactor to an absorber; supplying an absorber off-gas from the absorber to an absorber off-gas incinerator; and supplying fuel gas and air to the absorber off-gas incinerator; wherein a set of manipulated variables includes fuel gas flow to the absorber off-gas incinerator and the air flow to the absorber off-gas incinerator, and a set of controlled variables includes an amount of oxygen in the absorber off-gas incinerator stack gas and a temperature in the absorber off-gas incinerator, wherein controlling at least one set of controlled variable includes adjusting manipulated variables, wherein feedforward variables are used to change the manipulated variables.

21 . The process of claim 20 wherein feedforward variable include the amount of hydrocarbon in the reactant stream and the feed rate of the reactant stream.

22 . The process of claim 20 wherein the process includes controlling the amount of oxygen in the absorber off-gas incinerator stack gas and the temperature in the absorber off-gas incinerator based on model predictive control to determine simultaneous control actions for manipulated variable in order to optimize at least one set of parameters while controlling at least one set of controlled variables.

23 . The process of claim 20 wherein the process provides a temperature in the absorber off-gas incinerator within about 10° F. of a temperature set point of the off-gas incinerator.

24 . The process of claim 23 wherein the temperature in the absorber off-gas incinerator is maintained within about 5° F. of the temperature set point of the absorber off-gas incinerator.

25 . The process of claim 20 wherein the hydrocarbon in the reactant stream is selected from the group consisting of propane, propylene, isobutene, isobutylene and mixtures thereof.

26 . The process of claim 25 wherein the hydrocarbon is propylene.

27 . The process of claim 20 wherein the process provides about 5 volume % or less oxygen in an absorber off-gas incinerator stack gas.

Assignees

• Ineos Europe Ag

Inventors

• Shouche Manoj Shrikant
• Mcdonel Timothy Robert
• Couch Jay Robert

Classifications

• F23G2209/14

  Gaseous waste or fumes · CPC title

• F23G2207/30

  Oxidant supply · CPC title

• F23G2207/20

  Waste supply · CPC title

• F23G7/06 Primary

  of waste gases or noxious gases, e.g. exhaust gases (exhaust apparatus for engines with means for rendering the exhaust innocuous, e.g. by thermal or catalytic conversion, F01N3/08; combustion of uncombusted material from primary combustion within apparatus for combustion of solid or fluent fuel F23B {, of non combusted material from primary combustion of solid fuels; of gases produced by primary combustion of solid fuels F23B90/04}, F23C) · CPC title

• F23G5/50

  Control or safety arrangements · CPC title