US 2006/0213810 A1 · Apparatus and process for controlling temperature of heated feed directed to a flash drum whose overhead provides feed for cracking

Abstract

An apparatus and process are provided for cracking hydrocarbonaceous feed, wherein the temperature of heated effluent directed to a vapor/liquid separator, e.g., flash drum, whose overhead is subsequently cracked, can be controlled within a range sufficient so the heated effluent is partially liquid, say, from about 260 to about 540° C. (500 to 1000° F.). This permits processing of a variety of feeds containing resid with greatly differing volatilities, e.g., atmospheric resid and crude at higher temperature and dirty liquid condensates, at lower temperatures. The temperature can be lowered as needed by: i) providing one or more additional downstream feed inlets to a convection section, ii) increasing the ratio of water/steam mixture added to the hydrocarbonaceous feed, iii) using a high pressure boiler feed water economizer to remove heat, iv) heating high pressure steam to remove heat, v) bypassing an intermediate portion of the convection section used, e.g., preheat rows of tube banks, and/or vi) reducing excess oxygen content of the flue gas providing convection heat.

Claims26

Dependent claims

1-11. (canceled)

A process for cracking hydrocarbonaceous feed that comprises:

(a) preheating said feed in a first tube bank of a convection zone of a furnace, said feed being introduced to said first tube bank through at least one of
(i) an upper hydrocarbon feed inlet, and
(ii) a lower hydrocarbon feed inlet;
(b) mixing the hydrocarbon feedstock with water and steam added to the first tube bank via one or more inlets for introducing water and steam and removing said heated mixture stream through an outlet in said first tube bank, the water and steam being added in respective amounts which control the temperature of said heated mixture stream;
(c) further controlling said temperature of said heated mixture stream by at least one of:
(i) regulating the temperature of a second tube bank of said convection zone positioned beneath said first tube bank, by introducing high pressure boiler feed water through an economizer inlet and withdrawing boiler feed water of greater heat content through an economizer outlet;
and
(ii) regulating the temperature of a third tube bank of said convection zone positioned beneath said first tube bank by introducing high pressure steam through an inlet for high pressure steam, heating said high pressure steam, mixing desuperheater water with said high pressure steam to cool said high pressure steam, reheating said high pressure steam and withdrawing superheated high pressure steam from said third tube bank through an outlet;
(d) directing said heated mixture stream by a bypass line substantially external to said convection zone for receiving said heated mixture stream from said first tube bank to a fourth tube bank positioned beneath said second tube bank and said third tube bank, which fourth tube bank comprises an inlet connected to said bypass line and an outlet for directing a partially liquid effluent to a vapor/liquid separator;
(e) flashing said effluent from said fourth tube bank effluent in said vapor/liquid separator external to said convection zone to provide a liquid bottoms phase and an overhead vapor phase;
(f) directing said overhead vapor phase to a fifth tube bank of said convection zone positioned beneath said fourth tube with an inlet for receiving overhead from said vapor/liquid separator and an outlet in order to further heat said overhead vapor phase;
(g) cracking said further heated overhead vapor phase in a radiant zone beneath said convection zone, which includes a plurality of burners producing flue gas passing upwards through the radiant zone and convection tube banks, to provide a cracked effluent;
and
(h) withdrawing said cracked effluent from said radiant zone.

11 more elements

Dependencies are inferred from the claim text.

Facts

Application

11/445,006Filed 1 Jun 2006

Priority

21 May 2004

Published

28 Sep 2006

Term ends

Not estimatedThe source records don’t support an estimate.

Classification16 codes

C10G 9/20
Apparatus: tube furnaces
C10G 9/16
In pipes or coils with or without auxiliary means, e.g. digesters, soaking drums, expansion means: preventing or removing incrustation
C10G 9/206
Tube furnaces: controlling or regulating the tube furnaces
C10G 27/12
With oxygen or compounds generating oxygen: with oxygen-generating compounds, e.g. per-compounds, chromic acid, chromates

Apparatus and process for controlling temperature of heated feed directed to a flash drum whose overhead provides feed for cracking

Life of this patent

Apparatus and process for controlling temperature of heated feed directed to a flash drum whose overhead provides feed for cracking

Life of this patent

Abstract

Claims26