FIELD OF THE INVENTION

The present invention relates to the portable carbonization test apparatus / pilot coke oven. More particularly, the present invention proposes a fully automatic bench scale carbonization test apparatus / pilot coke oven with improvised box charging mechanism and coke cooling mechanism.

BACKGROUND OF THE INVENTION

It is well known that the coking coal is charged in coke ovens for carbonization to obtain the final product of coke and associated by-products like volatile hydrocarbons, coal chemicals, tar etc. For the study of coking behaviour of coal charge, the bench scale /pilot coke oven tests are carried out.

To carry out these tests, generally pilot coke oven of 200~300 kg coal charging capacity are used. This requires larger amount of coal charge, and, also, to complete one set of test it takes about 24 hours and involvement of 5 to 6 technical people. Prior to start the test such ovens requires 48 hrs heating cycle. Therefore, for quicker and less expensive tests a smaller, bench scale pilot coke ovens are used. Under this test pre-crushed coal (~ 80 % are less than 3.2 mm size) are kept inside a steel box or directly charged as cake and heated in the hot muffle furnace with controlled heating rate until the centre coke mass temperature reaches about 1000 0C. Gas generated during this process is taken out through a chimney and incinerated. After attaining the desired temperature, the box filled with red hot coke is taken out and quenched with water, and used for further laboratory tests. Such bench scale system with 2 to 30 kg charging capacity is common in various laboratories. During this test various constraints like uncontrolled rapid heating, leakage from furnace doors, non alignment of chimney, inefficient burning of by-product gas effluents etc, are faced. To counter these limitations, smaller bench scale coke ovens are designed by the present inventors with improvised coking and cooling facility with less than 6 hrs charging cycle with 1 to 2 man-power requirements.
With the improved design of the coke oven proposed herein all the above stated constraints have been sorted out.

Some of the relevant prior patents on the field are stated below as references :-

Indian Patent 269041 dated 21/02/2006 (SAIL) discloses a system for coal carbonization automation and process control in pilot coke oven. The invention was directed to achieve uniform carbonization all through the oven throughout the coking process and facilitate monitoring of the pressure etc.

CN87210932U discloses a coal coking furnace for the production of coke oven gas and tar.

WO2006103043A1 discloses a method and device for the carbonisation of coke with a high volatile content.

OBJECTS OF THE INVENTION

The principal object of the present invention is directed to provide a laboratory scale fully automatic electro-mechanical carbonisation test apparatus to simulate the coking process with commercial coke ovens.

A further object of the present invention is directed to provide an improved mechanism in the carbonisation test apparatus to reduce man power and time requirement for the carbonization test.

A still further object of the present invention is directed to provide a suitable carbonisation test apparatus which requires lesser quantity coal samples to complete the carbonization test.

A still further object of the present invention is directed to provide a suitable carbonization test apparatus which have less gas leakage during the carbonization test.

A still further object of the present invention is directed to provide a mechanism in the carbonization test apparatus for efficient door sealing for the furnace.
A still further object of the present invention is directed to provide a suitable carbonization test apparatus for proper incineration of the gases which are generated during the carbonization test.

A still further object of the present invention is directed to provide a suitable carbonization test apparatus for automatic heating control for the carbonization test.

A still further object of the present invention is directed to providing a suitable carbonization test apparatus in which coal can be charged in varying degrees of bulk density.

A still further object of the present invention is directed to provide a suitable carbonization test apparatus with foundation for furnace for the carbonization test.

A still further object of the present invention is directed to provide a mechanism in the carbonization test apparatus to obtain the desired centre coke mass temperature of the coal charge during charging.

A still further object of the present invention is to provide an improved carbonization test apparatus wherein the coke is cooled with N2 / Air without much burning of the coke.

SUMMARY OF THE INVENTION

In accordance with the stated objectives, the present invention discloses an integrated dry quenching bench scale coke oven used for lab scale carbonization test by including a number of features which provide more ease in carbonization test. In the existing bench scale carbonization systems there are door leakage problems while in the present invention a vertical lifting door has been provided which gives minimum leakages as well as required space to operate. Further, no significant openings are provided at any other face except opening at the top for the chimney. Due to its specially designed charging box system dry quenching can be done with air also with significantly low burning losses.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Fig. 1 illustrates the left side elevation view of the apparatus in accordance with the present invention;
Fig. 2 illustrates the right side elevation view of the apparatus in accordance with the present invention;

DETAILED DESCRIPTION OF THE INVENTION

Coke is a solid carbon fuel and carbon source used to melt and reduce iron ore in the production of steel. Coking ovens have been used for many years to convert coal into metallurgical coke. During the coking process, finely crushed coal is heated under controlled temperature conditions to de-volatilise the coal and form a fused mass of coke having a predetermined porosity and strength. Because the production of coke is a batch process, multiple coke ovens are operated simultaneously.

The melting and fusion process undergone by the coal particles during the heating process is an important part of coking. The degree of melting and degree of assimilation of the coal particles into the molten mass determine the characteristics of the coke produced. In order to produce the strongest coke from a particular coal or coal blend, there is an optimum ratio of reactive to inert entities in the coal. The porosity and strength of the coke are important parameters and are determined by the coal source and / or method of coking. For the estimation of the expected coke quality from the specified coal blend, especially if coals being used are new for the commercial ovens, it is required to conduct laboratory scale carbonisation tests to avoid any possible damage to the commercial ovens.

For the study of coking behaviour of coal charge, the bench scale coke oven tests are done. Under this test pre-crushed coal (~ 80 % are less than 3.2 mm size) are kept inside a steel box and heated in the hot muffle furnace with controlled heating rate until the centre coke mass temperature reaches to 1000 Deg. C. Gas generated during this process is taken out through a chimney and incinerated. After attaining the desired temperature, the box filled with red hot coke (a solid coherent mass generated from the destructive distillation of the bituminous coal in the absence of air) is taken out and cooled either with water or with passive gas (dry cooling), and used for further laboratory tests. For small scale tests where coke samples generated are very less quantity, focus is given for minimum manual interference and least variation in testing method. When coke sample are cooled with water there is always a chance of sample breakages and variation in results. Therefore this system of dry quenching facility has been developed where cooling can be done using passive gas (N2).

In an exemplary embodiment, the coal is kept into a steel box and heated (up to 11000 C) from two sides only (as done in coke ovens) as shown in the accompanying Fig. 1 and Fig. 2 .

The details of the components of the invented carbonization test apparatus (Fig. 1 and Fig. 2) are given below-
1-chimney burner, 2 - pusher ram, 3,4 - motor driven assembly for pusher movement, 5 - coking furnace, 6 - coking chamber entry door, 7- pusher plate, 8 -chimney for gas exit, 9 - gas incineration system, 10 - dry quenching system, 11- cooling chamber door, 12 - cooling gas re-circulating system, 14,15 - heating side of coking chambers, 16 - structure , 17- charging box, 18,19,20 - trolley for box movement, 21 - arrangement for gas cooling, 22- coking chamber.
According to the invention there is provided a fully automatic bench scale carbonization test apparatus including integrated dry quenching system comprising:
a steel box configured to be heated up to 11000 C which is covered from all sides after keeping the coal charge inside;
a coking furnace with two sides wall heating facility;
a dry / gas cooling chamber for coke cooling ;
an automatic heating control and regulation system;
a fully automatic coking and cooling system.

The carbonization test apparatus of the invention includes a vertical moving door.

The said automatic heating control and regulation system are adapted to multi-level segmented heating in the furnace.
In the carbonization test apparatus a dry cooling chamber is included.
The carbonization test apparatus further includes a platform mounted frame structure.
In the carbonization test apparatus the furnace body and door are made of welded heavy-duty mild steel.
In the carbonization test apparatus the refractory lining of the box and the door is configured for withstanding continuous temperature up-to 11000 C.
In the carbonization test apparatus a hole made of high alumina tube is provided at the top of the furnace to insert a chimney for taking out the gas.
The said chimney is equipped with a heating coil for incineration of the gases.

In the carbonization test apparatus the cooling chamber is designed in such a manner that coke in the box can be cooled with air also, by recalculating and cooling of the quenching gas.

This system is helpful in simulating commercial oven heating. The box (Fig. 1, part 8) is covered from all sides after keeping the coal charge inside. There is a hole onto the cover of the box at the middle for the exit of the gases during the carbonization. Another hole (dia. 40 mm) is required at the front face of the box, at the height 100 mm from bottom. The hole will be connected with the inner compartment of the box with conical shape pipe as shown in the drawing. Purpose of this arrangement will be, to insert the thermocouple properly and to minimize the gas leakage from the box through this hole. Accordingly, there should be two holes required at the furnace body– one at the top and another at the side of the furnace. These holes should be aligned with the holes. The proposed system will have three major parts –
1. Structure
2. Coking furnace and
3. Dry cooling system

1. Structure
• The Whole system will be mounted on platform and beam (refer to the drawing). It will consist of electrically operated lifting and moving systems.
• The furnace will be mounted on the top of the platform. the coal charged box (total weight about 60 Kg) will be lifted on the platform with the help of either a jib crane or other suitable mechanical arrangement as illustrated in the drawing .
• After coking, both the doors will be opened and hot box will be pushed with the help of pusher and it will be fed in the quenching tower (discussed in coming lines)
• Pusher will be operated using electrical and mechanical arrangement as shown in the drawing.

2. Coking furnace
• The proposed furnace will be used for the evaluation of coking of coals. For this purpose, coal will be kept into a metal box and shall be heated (up to 1100 0C) from two sides only (as done in coke ovens).
• To avoid heating from the front and back side of this box, compartments have been created in both sides that will be filled with suitable heat insulators. This will help in simulating commercial oven heating.
• The box is covered after keeping the coal charge inside. There is a hole onto the cover of the box at the middle for the exit of the gases during the carbonization, .
• Another hole is required at the front face of the box, at the height 100 mm from bottom. The hole will be connected with the inner compartment of the box with conical shape pipe as shown in the drawing. Purpose of this arrangement will be, to insert the thermo-couple properly and to minimize the gas leakage from the box through this hole.
• Accordingly, there are two holes at the furnace body– one at the top and another at the side (onto the front door) of the furnace.
• The purpose of the hole at the top of the furnace is to insert a chimney for exit and incineration of the gases, generated during the coal carbonization test. The hole at the front door of the furnace will be used to insert the thermo-couple inside the coal charge.
• There are three thermo-couples (with sheath) required – one for the temperature monitoring & control of furnace temperature (inside), second for the centre coke mass temperature measurement and, the third for over temperature protection.

3. Dry cooling system
• The dry cooling system consists of a rectangular cuboids box (approximate dimensions in mm: 650 L X 400 w X 600 H) with sufficient space for coal charge box keeping and cooling. The cooling box is made of proper inner lining to withstand temperature of 1100 0C to 100 0C for 6 hours
• Under this arrangement, once the coking is completed, both doors of the furnace will be opened and the and hot coal charged box will be pushed using pusher mounted on another side of the furnace. Once hot coal charged box containing hot coke is shifted into the cooling box, the cooling box will be shifted back and attached to the N2 gas line and inlet / outlet of gas circulating line.
• Cooling chamber door is made air tight so that once it is closed it should not ingress oxygen from outside to minimize burning losses.
• From the bottom of the cooling tower two inlets provision are made, one for supplying pressurised N2 gas and another for inlet of circulated gas to be provided.
• From the top of the cooling tower a provision for the outlet for hot N2 gas (re-circulating) is to be provided as per the drawing.
• This hot N2 gas (re-circulating) is cooled through copper tube cooling system which consists of a spray from top and then tubes are passed through water tank to cool the gas further or to be provided similar type heat exchanger.
• This cooled gas is again re-circulated using a pressure pump / compressor.
• A provision for makeup N2 gas from cylinder has also been provided.
• Thermo-couples at the inlet / outlet of the gas have been provided to measure the cooling efficiency of the system.
• Regulation knob has been provided at the inlet of the gas .

INVENTIVE STEP
The inventive steps and features of the system of carbonisation test apparatus are:
1. There was no lab scale coke oven / carbonisation test apparatus available using the concept of dry quenching system using not only with inert gases but also with air.
2. Due to the fact that its door moves vertically upward this system operates in less space.
3. This innovation consists of special type of chimney which ensures complete burning of the gases produced during carbonization.
4. Programmable heating in multiple segments.
5. Dry quenching along with gas re-circulating facility to utilize minimum cooling gas requirement.
6. Fully automatic system with minimum manual interference.
7. Cooling of box packed with coke is done in the inert cooling chamber, that will enhance the box life and reduce the burning loss.
8. A roller type base is introduced in the cooling chamber for easy movement of the metal box and proper distribution of the circulating cooling chamber.
9. Separate provision for N2 supply to control and minimize use of nitrogen.

Although the foregoing description of the present invention has been shown and described with reference to particular embodiments and applications thereof, it has been presented for purposes of illustration and description and is not intended to be exhaustive or to limit the invention to the particular embodiments and applications disclosed. It will be apparent to those having ordinary skill in the art that a number of changes, modifications, variations, or alterations to the invention as described herein may be made, none of which depart from the spirit or scope of the present invention. The particular embodiments and applications were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such changes, modifications, variations, and alterations should therefore be seen as being within the scope of the present invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.

WE CLAIM:

1. A fully automatic bench scale carbonization test apparatus including an integrated dry quenching system comprising :
- a steel box configured to be heated up to 11000 C which is covered from all sides after keeping the coal charge inside;
- a coking furnace with two sides wall heating facility;
- a dry / gas cooling chamber for coke cooling ;
- an automatic heating control and regulation system;
- a fully automatic coking and cooling system.

2. The carbonization test apparatus as claimed in claim 1, which includes a vertical moving door.

3. The carbonization test apparatus as claimed in claims 1 and 2, wherein the automatic heating control and regulation system are adapted to multi-level segmented heating in the furnace.

4. The carbonization test apparatus as claimed in claims 1 to 3, wherein a dry cooling chamber is included.

5. The carbonization test apparatus as claimed in claims 1 to 4, wherein the apparatus further includes a platform mounted frame structure.

6. The carbonization test apparatus as claimed in claims 1 to 5, wherein the furnace body and door are made of welded heavy-duty mild steel.

7. The carbonization test apparatus as claimed in claims 1 to 6, wherein the refractory lining of the box and the door is configured for withstanding continuous temperature up-to 11000C.
8. The carbonization test apparatus as claimed in claims 1 to 7, wherein a hole made of high alumina tube is provided at the top of the furnace to insert a chimney for taking out the gas.

9. The carbonization test apparatus as claimed in claims 1 to 8, wherein the chimney is equipped with a heating coil for the incineration of the gases.

10. The carbonization test apparatus as claimed in claims 1 to 9, wherein the cooling chamber is designed in such a manner that coke in the box can be cooled with air also, by recalculating and cooling of the quenching gas.