EP0686180A1

EP0686180A1 - Method of producing coke for the iron and steel industry

Info

Publication number: EP0686180A1
Application number: EP94909066A
Authority: EP
Inventors: Joachim F. Meckel; Friedrich RÖSNER; Friedhelm Kerstan
Original assignee: Veba Oel Technologie und Automatisierung GmbH
Current assignee: Veba Oel Technologie und Automatisierung GmbH
Priority date: 1993-02-26
Filing date: 1994-02-25
Publication date: 1995-12-13
Also published as: DE4306057A1; CA2157052A1; AU6206794A; JPH08509509A; WO1994019425A1; DE4490891D2

Abstract

Proposed is a method of producing coke for use in the manufacture of iron and steel, in particular foundry coke, by mixing charge coal and about 0.5 to 10 %, relative to the coal in the water-free and ash-free state, of a binder, and then coking the mixture. The aim is to produce coke with a relatively low reactivity, the highest possible unit density, the highest possible carbon content and the largest possible lump size. Used as the binder is a vacuum-hydrogenation residue produced in the vacuum distillation stage of the hydrogenation of short residues or heavy oils derived from crude oil, with the addition of an additive consisting of porous carbon bodies made, in particular, of material derived from coal.

Description

Process for the production of coke for the iron / steel industry

The invention relates to a method for producing coke for the iron or steel industry, in particular cast iron reok coke.

Charges which are already suitable without admixtures to give a coke with the desired property values, such as a certain lump size and a certain abrasion behavior, are hardly available to the extent necessary. In order to obtain the desired property values, it is known in coke production, in particular in foundry coke production, to add about 5% petroleum-derived pitch, based on the water-free and ash-free coal, to the feed coal, which can already be a mixture of several coal components and coke breeze .

This binding material is particularly indispensable when foundry coke with a high carbon content is to be produced, since then coke breeze is also used as an essential input coal component.

The petroleum-based pitch is comparatively expensive.

From US-A-4, 234, 387 a manufacturing process for metallic coke is known, in which a coking coal mixture with unfavorable coking properties is mixed with a binding agent, which is used, for example, as a vacuum distillation residue from the hydrogenation of heavy oils or bi ¬ tumen arises; however, the vacuum distillation residue from the hydrogenation of bitumen from tar sands is preferred.

£ RSrtrrßLATT REGE This binder is used in amounts of up to 20 percent, preferably between 5 and 15 percent (based on the coking coal mixture). The starting mixtures thus produced for the coking process have comparatively moderate dilatation and contract values. However, the stronger the contraction, the greater the sintering effect of the finely divided coking coal particles at the beginning of the gas expulsion of the coking coal, ie before it softens. The subsequent dilation as a result of the expansion during the further outgassing of the coking coal is to a considerable extent responsible for the construction of the coke framework. The cokes produced by this known method therefore have a comparatively low stability factor and a comparatively low hardening factor - this means low drum strength and relatively high abrasion.

Proceeding from this, the teaching of the patent claim solves the problem of producing a coke for the iron / steel industry with a relatively low reactivity, as high a piece density as possible, as high a carbon content as possible and as large a piece as possible.

The invention extends, inter alia, the basis of the binders which can be used and, preferably, uses a particularly inexpensive binder which is as little harmful to health as possible.

Experiments have shown that the binder according to the invention leads to the same coke properties as when using so-called petropech, the binder according to the invention being considerably cheaper and containing extremely little carcinogenic ingredients. In principle, the method according to the invention can also be used successfully in the production of blast furnace coke. The decisive factor is the additive in conjunction with the other hydrogenation feedstocks, to which the additive is preferably added in 1 to 3% by weight, based on the entire hydrogenation feedstock. This additive consists of porous carbon bodies which, in particular, consist of carbon-based material and whose inner surface area is as few as possible a few hundred, typically 300 2 m / g.

Surprisingly, this additive not only has a reaction-stabilizing and quality-increasing effect on the hydrogenation products, but also acts as a constituent of the vacuum hydrogenation residue as a scaffold for the coke structure in the coking process according to the invention.

Porous carbon bodies can be produced in a wide variety of ways and are generally known; however, their effects on the quality of coke, in particular for the iron / steel industry in connection with the process according to the invention, were in no way foreseeable.

The hydrogenation of petroleum and petroleum-derived products, such as heavy oils and vacuum residues is known per se and, inter alia, in the book of hydrogenation technology "Catalytic pressure hydrogenation of coal, tars and mineral oils" by Dr. Walter Krönig, Springer-Verlag, 1950. The hydrogenation conditions vary depending on the feed to be hydrogenated. In any case, it is carried out with the addition of hydrogen at elevated pressure and temperature, typical reaction conditions being 100 to 300 bar system pressure at temperatures between 200 and 500 ° C. wear. This high-pressure hydrogenation is preferably carried out in a so-called bottom phase reactor. The product stream leaving the bottom phase reactor consists of oils, solids and gases and is subsequently described, for. B. in a hot separator, separated into two phases, namely a top product and a bottom product. The bottom product is separated from distillable oils in a subsequent vacuum column (vacuum hydrogenation residue).

According to the invention, the use of the hydrogenation residue which is obtained in the hydrogenation by the so-called VCC process (\ / EBA-C_ombi-C_racking process) is particularly preferred. The latest status of the VCC process was presented at the DGMK main conference in 1990 in Münster / estal under the title "New aspects of the VCC process" by Dr. Klaus Niemann published. There is therefore no need to describe it here.

Embodiment

A large-scale VCC plant with 95% conversion processes the starting materials shown in Table 1 and produces the products shown in Table 2. The feedstocks are specified in Table 3 and the products in Table 4. The solidified vacuum hydrogenation residue from the vacuum column to be used according to the invention has the chemical-physical properties and grains shown in Table 5 and was subsequently used in a large-scale test on a coking plant as a binder of the input coal, consisting of a mixture of

32.4% of a low-volatile coal with poor coking properties (non-coking coal),

48.6% of a medium-volatile coal with good coking properties (prime coking coal) and 14.0% coke breeze and 5% by weight of the vacuum hydrogenation residue,

added to make foundry coke. The coking coal mixture and the coke properties obtained after a 33-hour cooking time are shown in Table 6. The results obtained with the vacuum hydrogenation residue used as a binder according to the invention (right column of Table 6) were compared with the normal operating results of the kokerei (Petropech as a binder) according to the prior art (Table 6, left column) .

The coking took place in several ovens of a large-scale coke oven battery (Otto type, chamber width 450 mm,

3 chamber height 5.10 m, chamber length 13.1 m, volume 27.64 m).

This large-scale experiment was preceded by many small-scale experiments with the binder according to the invention and other mixing ratios in the order of 3 to 7% binder based on the water-free and ash-free coal used. These small-scale experiments were carried out as optimization requests in comparison to the use of the conventional binder.

Coke output could be increased by the invention; as Table 6 makes clear.

The binder according to the invention contains surprisingly little polycyclic aromatic hydrocarbons. Table 1

Feed material kε / h

Vacuum residue 166,666 additive 1,667

Fresh hydrogen 7,042 turbine condensate 12,750

Total 188,125

Table 2

Products k £ / h

MD gas 8,384 LP gas 13,045 Off gas 18

Naphtha 24,081

Gas oil 86,563

Vacuum gas oil 31,525

Vacuum hydrogenation residue 9.203 sour water 15.306

Total 188,125 Table 3

Specification of the input materials

Vacuum residue: Arabian Light

TBP intersection ° C 565 +

Density (15 ° C) kg / dm3 1.022

Carbon wt% 84.38

Hydrogen wt% 10.30

Sulfur wt% 4.34

Nitrogen wt% 0.38

Oxygen wt% 0.6

Ash weight Ψc approx. 0.02

Solids not specified

Nickel ppm. Weight 25

Vanadium ppm. Weight 114

Iron not specified

Asphaltene weight% 10

Conradson Carbon wt% 20.3

viscosity

50 ° C cSt 150,500

100 ° C cSt 1,589

Additive: porous carbon body made of carbon-derived ₂ material with an inner surface of about 300 m / g (practically not changed by the hydrogenation, as far as can be seen)

Fresh hydrogen

Hydrogen (H2) min. 99.6 mol%

Nitrogen (N2) max. 0.2 mol%

Methane (CH4) max. 0.1 mol%

Ethane (C2H6) max. 0.1 mol% Table 4

Specification of the products

MD / ND gas: internal use

naphtha

- TBP boiling range C5 + -180 ° C

- sulfur <20 ppm

- nitrogen <20 ppm

- Gap gasoline / gas oil

(ASTM D86 95/5%) min. 15 ° C

Gas oil

- TBP boiling range 180-343 ° C

- sulfur <100 ppm

- Water content <50 ppm

- Cetane number> 38

- Overlap gas oil / vacuum gas oil

(ASTM D86) 95/5% max. 30 ° C

Vacuum gas oil

- TBP boiling range 343 ° C +

- sulfur <600 ppm

- nitrogen <600 ppm

- aniline point -

- Metals <1 a.m.

solidified hydrogenation residue

(contains the additive used)

- TBP boiling range 524 ° C +

^β analysis

C 86.0% by weight

H 6.0% by weight

O 0.5% by weight

N 1.0% by weight

S 2-5 (2-4) wt%

Inorgan. Components 4.0 (2-4) wt%

Solids (Tuolol insoluble) 20-40 Table 5

⁰ Chemical-physical properties

Density 1,300-1,500 kg / m3

(at 15 ° C)

Bulk density 500-700 kg / m3

Pour point 150 ° C

Flash point <200 ° C

Ignition temperature <470 ° C

Softening point 120-160 ° C

Calorific value 36 MJ / kg

Calorific value 37 MJ / kg

Volatile components 40-70%

⁰ grain analysis

6.3 mm approx. 6% by weight

6.3-3.15 mm approx. 40% by weight

3.15-2.00 mm approx. 20% by weight

2.00-1.00 mm approx. 17% by weight

1.00-0.5 mm approx. 5% by weight

0.5 mm approx. 10% by weight

RULES 26)

Claims

Claim

Process for the production of coke for iron / steel production, in particular foundry coke, by mixing charcoal and from about 0.5 to 10%, based on the water- and ash-free charcoal, a binder and subsequent coking which is used as the binder a vacuum hydrogenation residue which is obtained in the vacuum distillation of the hydrogenation when petroleum-derived vacuum residues or petroleum-derived heavy oils are hydrogenated with the addition of an additive consisting of porous carbon bodies, in particular of carbon-derived material.