Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
FIRE FIGHTING PROCESS IN FLAMMABLE LIQUIDS DEPOSITS THROUGH SMOTHERING, COOLING AND TRANSFERENCE
Document Type and Number:
WIPO Patent Application WO/1996/023548
Kind Code:
A2
Abstract:
For the extinction of fires in flammable liquids (fires Class B) - with partial recovering of the product under risk - consists summarily of: (1) Normal Storage Tank (RN) to be considered as the hit one; (2) pipes for the liquid drainage through the bottom of the Normal Tank (V1 to V2); (3) heat exchange winglets equipped pipe, immersed in the water of artificial lake, to cool the liquid; (4) Emergency Storage Tank (RE), of similar characteristics as the burning one (RN); (5) valves (V1, V2, V3, V4) and motor-pumps (B1, B2) to operate the Process - all of them motorized and with operation/signalling remote action; (6) temperature indicator (TM1, TM2) and liquid level devices (NMAX1, NMAX2, NMIN1, NMIN2), which operate electrical alarm and Process remote action automation circuits; (7) Return Circuit (V4 to V3) - of the liquid, direct to the original Tank - without using the cooling stage - but equipped with all other resources as those of drainage (or transference) one.

Inventors:
DE CASTILHO PAULO ARTHUR LEMOS (BR)
Application Number:
PCT/BR1995/000062
Publication Date:
August 08, 1996
Filing Date:
December 14, 1995
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CASTILHO PAULO ARTHUR LEMOS DE (BR)
International Classes:
A62C3/06; (IPC1-7): A62C/
Foreign References:
US5163517A1992-11-17
Download PDF:
Description:
FIRE FIGHTING PROCESS IN FLAMMABLE LIQUIDS DEPOSITS THROUGH SMOTHERING, COOLING AND TRANSFERENCE

1 - The Fire Combat in Flamable Liquids Deposits Process, whose Patent is requested in this document, is supported by the physical-chemical phenomena in which it is based and in the application of currently used equipments. 2 - The preocupation in developping a simple and highly efficient Process for this objective and application had its origin in the worlwide newspapers registrations of such fires, which are frequent even in Oil Refineries. Such fires usualy result in very heavy losses in equipments, tanks, and fuel, because they have been extinguished only after the total consumption of the flammable liquid involved. This results from the low efficiency of the present combat means available in opposition to the enormous quantities of liquid and the extra high combustion temperatures faced.

3 - BASIC PRINCIPLES OF FIRES

3.1 - Combustion is the quick chemical compound of a combustible with oxigen followed by heat and luminous energy liberation. This corresponds to a quick oxidation. 3.2 - The combustion requirements -

The following elements are necessary to create a combustion:

1. a mixture of fuel and air (in vapor condition) , in adequate proportions; 2. exposition of fuel particles to the oxigen, lasting sufficient time to allow their combustion;

3. maintain the combustion zone at a temperature higher than that of fuel's ignition one;

4. or, in an abridged manner: fuel, oxigen and heat. 3.3 - On the other side, oxidant reactions that occurr in fires are chieffly exothermic.

That is where the extreme difficulties in applying the usual resources to extinguish fires on so big deposits as that in Refineries - such as water/water fog/vapor/ chemical or

mechanical foams - come from, usualy resulting high money losses not only in fuel but also in equipments and materials involved.

4 - This Process to be patented in supposed to be applied to a already started fire, no mater of its origin: it is not a prevention mean but a fire combat one.

5. PROCESS DESCRIPTIVE REPORT

The present Process, whose Patent is requested, is characterized by three Steps (A.R.T.) in rigorous succession order, as follows:

5.1 - Smothering - of the burning fuel, by means of leading it out of the storage tank through its bottom end;

5.2 - Cooling - the liquid by means of making it flow under a mass of water (an artificial, perhaps decorative lake) of wide surface area;

5.3 - Transferring (recovering) - the liquid to other similar tank.

Observing this sequence, and eliminating one of the indispensable fire feeder elements by means so simple as possible, will this Process not only overcome the conditions present in a big dimensions fire - and extinguish it - but also allow the recovering of most part of the liquid involved and the protection of the fired tank and his equipments. According to the drawings, there are siimmarily: 5.1.1 - The smothering is obtained by discharging the flamable and already burning liquid through the bottom end of the storage tank (or reservoir) ; this is the point. The liquid placed out of contact from the atmospheric oxigen burns no more. It is advisable that the bottom of the tank could be conical, in order to turn easier the liquid flow out of the tank and quicker the reduction of the surface still in contact with oxigen.

NOTICE - It is useful to remember that only the liquid's highest layer that is in contact with the oxigen in the air, can burn. The fire spreading to the immediate lower layers would be done by means of the temperature rising above the one of the liquid's ignition temperature, added by its vapors releasing-

5.1.2 - The liquid's cooling is obtained by both means; gravitational and forced circulation through a pipe equipped with metallic heat diffusion winglets immersed into mass of water (artificial lake) with sufficient volume and superficial area to maintain water below its boiling temperature and, consequently, below that one of the pumped liquid surely below its ignition one. Circulation, aeration, and automatic renew of this refrigeration water - just when a fire is started - would be an additional resource to assure the improvement of present Process efficiency.

5.1.3 - The transference (recovering) of the liquid, already sufficiently cooled, is obtained guiding it to a standby (or emergency) storage tank with similar characteristics and same capacity of the one involved in the fire accident.

Due to the same reasons, this standby tank will have the same operational resources which allow the inverse circuit works to later return the recovered liquid to the original tank.

6 - Essential Process Elements -

6.1 - The clarifying drawings attached, although not including Process elements technical sizes, or dimensions, nor automatization or control diagrams, contain at least sufficient information to the complete Process characterization, its understanding and operation. So we have:

6.2 - Foreseen, the Process is completely automated allows immediate start so long as the liquid reaches the pre-determined limit temperature; although where possible, manual operation functions would be accesible as an additional means.

6.3 - Electrical energy supply must be of the same usual characteristics as that of the region where the tanks are installed, so allowing immediate interchange of replacement of any of its components, and will be supported by an automatic starting emergency generator.

6.4 - The essential components, according to the

electrical layout - simplified to a single normal tank - are:

6.4.1 - Normal Tank or Reservoir (RN) , where the fire is supposed to start; it is equiped with electrical circuits drivers, as:

2 couples of liquid's maximum temperature (TMI) thermo¬ electric relays (normal plus reserve) ; 2 liquid's maximum level (N Max 1) indicators (normal plus reserve) ; 2 liquid's minimum level (N Min 1) indicators (normal plus reserve) ;

6.4.2 - Motor operated valve (V I).

6.4.3 - Drainage and transference pipe

6.4.4 - Transference motor-pump (Bl) . 6.4.5 - Artificial lake with adequate area and depth.

6.4.6 - Steel pipe equipped with heat diffusion wings to refrigerate the liquid inside it, immersed in water (as in 6,4,5 above)

6.4.7 - Motor-operated valve (V 2) . 6.4.8 - Emergency Tank or Reservoir (RE), equipped with electrical circuit drivers similar to the Normal Tank (RN) , but identified as follows: 2 couples of liquid's maximum temperature (TM 2) thermo¬ electric relays (normal plus reserve) ; 2 couples of liquid's maximum level (N Max 2) indicators (normal plus reserve) ; 1 liquid's minimum level (N Min 2) indicators (normal plus reserve) .

6.4.9 - Manual started liquid's return circuit, containing:

1 Motor-operated valve (V4) ; 1 Return motor-pump (B 2) ; 1 Motor-operated valve (V 3) .

7 - PROCESS OPERATION - Starting a fire in a flammable storage tank (RN) , the normal/reserve (TM 1 - fig. 2) thermo electric relays will close electrical circuits and simultaneously trip:

7.1 - luminous and sound alarms at Refinery's Operation

Room;

7.2 - open the burning storage tank's (RN) bottom valve (V 1) ;

7.3 - start of the drainage and transference otor- pump (B 1) ;

7.4 - open of the emergency storage tank's (RE) bottom valve (V 2) , where the liquid will be relocated.

8. - Due to the physical-chemical principles in which the Process is based, only the liquid's supperficial layer will be burning.

9. - Adjacent layers retreat, through the bottom, will avoid the possibility of its contact with the oxigen in the atmosphere, and will lead, in later moments, to lesser quantities of liquids capable of burning in the damaged Normal Storate Tank (RN)

- so less quantities of liquid as the higher can be the velocity applied to its transference. 10. - Refrigeration of the liquid, due to its circulation inside the mass of water of the artificial lake, will assure its temperature to be maintained below its critic value, known as that of auto-ignition, inside the Emergency Storage Tank (RE) . 11.- When the Minimum Level (N Min 1) in the Normal Storage Tank (RN) is reached, the pertinent electrical contact will open and the Process will stop. 12.- The recovered liquid, expected to be in its major portion, will be contained inside the Emergency Storage Tank (RE) . It will be at the Refinery Control disposal to be returned to the Normal

Storage Tank (RN) , by means of manual started operation liberated by both Maximum (N Max 2) and Miminum (N Min 2) Level Indicators, as soon as the working conditions of the damaged tank (RN) can be recovered and when the global safety allows.

13.- The pumping of the liquid in its return to the

Normal Storage Tank (RN) may be started, when the Maximum (N Max 2) and Minimum (N Min 2) Level

Indicators are closed. The starting will be done by manual means (preferably) or by remote control; otherwise, valves V3 and V4 openings and motor-pump (B 2) start are free to be remotely set.

14.- Return pumping will be automatically stopped by the Emergency Storage Tank's (RE) Minimum Level Indicator (N Min 2) , resulting in motor- pump shut-off and valves V3 and V4 closed.

15.- Ample advantages not only in saving raw-materials but also equipments, operation time, and labor force will be obtained with the application of the present Process.