US2033644A - Retort lining - Google Patents

Description

COMPOSITIONS, F COATING 0R PLASTIC, Patented Mar; 10, 1936 I I I D S T The present invention relates to material for lining retorts, stills, fractionators, and like appaw ratus in which high temperature, and often high pressure, hydrocarbon vapors are generated for the proper fractionating of petroleum and for tilliie separation of sulphur, coked particles and the All retorts subject to pressure'require steel or iron in their structures and it is found that under the usual operating temperatures the impurities are highly corrosive, this being particularly true of the sulphur. H a a Again it is found that fine coke particles or free carbon particles are thrown out of the va pors and these find their way into the most minute crevices of still linings.

A wide variety of linings are employed for this work and these naturally provide, or quickly develop, cracks which permit gases and coke par-v ticles to enter. In this way, even if the lining succeeds in adhering to the metal walls, sulphur vapors are free to reach and attack the iron walls. Again the action of coke particles seems to be that of continually crowding into the interstices and further acting to break down the lining.

Thirdly, some linings which are fairly satisfactory in other respects do not withstand the destructive action required when coke accumultions are being chipped off after a period of op-. eration. It is common practice, after hours of operation, for workmen to enter the retort and chip off coke accumulations with chipping hammers. .It is therefore essential that the lining be capable of withstanding this action without developing cracks which would subsequently admit sulphur to the steelfwalls. s

From the foregoing it is apparent that a problem presents itself quite distinct from that encoun-' tered with ordinary linings for resisting corrosion of metal walls. Petroleum retort linings which are hard and dense at the outset readily crack. Others that meet some of the requirements do not withstand the action of chipping hammers when coke accumulations are being removed. Still others, which possess some of the necessary characteristics cause the coke to combine with the structure of the lining in such marmer that the coke is not readily parted therefrom and the lining is often badly damaged in attempts to remove the coke.

Again, linings which, under conditions other than those encountered in petroleum retorts, are satisfactory, fail in the presence of hydrocarbons which throw off fine coke or carbon particles.

2,033,644 an'ronrnmn za chimes L. Newport and Herbert G. Smith, ,1. 1 ,1 Los Angeles, Calif.

No Drawing. Application September 15, 1933, Serial No.689,620. Renewed January 29, 1936 4 Claims. (01. 196-133) i This is believed to be due to the fact that these particles enter most minute crevicesand gen-' PAT ENT" erate destructive pressures which further en'- large the cracks until finally, both coke and sulphur find their way between the steel walls and the lining.

It is the primary object of this invention to provide a retort lining, particularly for this class of work, which is resistant to acid and sulphur vapors; secondly which is economical and readily applied; thirdly which strongly adheres to steel walls and which after long use will permit of coke accumulations being removed without cracking the lining; and fourthly which will withstand the usual temperature changes without loosening" or cracking.

- In addition to the foregoing requirements, it

is obvious that a long lived lining must adhere to the walls at all points in such manner that.

particles working into the structure of the lining will not build up between the lining and the steel wall of the retort and so act to corrode the steel while loosening the lining.

Retorts for the fractionating of petroleum are of course lined when cool and it becomes another object of the invention that the lining be readily applied. When the still is heated it is obvious that the metal walls undergo expansion sulphur vapors or particles from passing thru it to the lining, and the final tensile strength and other physical properties essential for the successful removal of coke accumulations without damage.

Accordingly, in carrying out the present invention we provide a retort lining which possesses the qualities essential for convenient application and for successfully withstanding the initial conditions; the material used having the peculiar property of being acted upon by certain elements in the petroleumto result in a new material possessing the physical and chemical characteristics required to stand up under all usual conditions subsequently encountered.

In carrying out the present invention inone particular application we employ a plastic mixture composed approximately 50% by weight of cement or binder and 50% by weight of a material or mixture comprising a high percentage Per cent Portland cement by weight 50 Shredded mineral wool by weight 33.3 Diatomaceous earth by weight -16.?

These ingredients are mixed with .just enough water to produce a plastic mixture ready for application. Where added plasticity is required to aid in ready application asmall amount of clay particularly a gelatinous clay, may be added but care is always exercisedso that the clay will not reduce the voids of the finished material.

This mixture whenappliedto a steel surface in plastic condition will be found to adhere readily, although of course any of the usual expedients such as .wiremesh'may be used as a supporting element. The plastic mixture will be found to adhere closely. to metal walls both when applied and after it has dried.

Usually stills or retorts are down no longer than necessary and it isfound that heat can be applied to the still within 24 .hours after application of the lining. Both during drying, as well as during the initial application of heat, the lining is found to be suitably resilient and does not crack or spall; this property being most essential to final success.

When quite dry-however this mixture would not ordinarily possess the required tensile strength, and tests prove-that it is not impervious to gases. In the initial mixing of a batch the wool and diatomaceous earth becomes dispersed thru the mixture in suchmanner that when it is set, the cement forms: a net-work of suitable strength, while, due to the characteristics of the wool and the diatomaceous earth the lining is relatively porous and elastic while capable of acting as afilter for thefinest of coke particles.

Chemically the wool is practically balanced between the acid and basic, being-composed essentially of calcium and silica, in equi-molecular proportions. While the temperatures to which the lining is usually subjected in petroleum fractionating do not usually exceed 950 degrees F. the chemistry of the complete lining is believed to be important.

After the lining has been'in use, the linings are still intact after more than one year of use,

.it is found that the entire structure of the lining changes by reason of the original lining becoming impregnated with carbon and sulphur. When so impregnated the lining has increased strength, and if such is possible, adheres even more firmly to steel walls and becomes seemingly an integral part thereof.

On the outer surface of this lining coked residue will build up in a hard formation which may be chipped away at intervals without damage to the underlying lining, and a distinct cleavage is usually manifest between the lining proper and the incrustations which form.

While in the initially dried lining, before the retort is put into operation, a cross section of as to absorb sulphur vapors, and the accumulation of this foreign material in the interstices of the lining finally results in a hard, dense and relatively impervious lining adhering firmly to the metal walls and finally excluding sulphur and other corrosive vapors from the steel surface to the extent that months of operation show no apparent corrosion. The lining thus formed is of course highly resistant to the action of the very elements of which it is partially composed.

We are not limited to the specific ingredients or the specific proportions mentioned and we find that other ingredients and proportions will carry out the invention, although we do find that mineral wool is ideal for providing a suitably resilient structure and as an adsorbent for coke and sulphur. The scope of our invention is therefore not limited to the foregoing specific ingredients and proportions and same may be varied within the scope of the appended claims without departing from the spirit of our invention.

We claim:

1. In combination with a petroleum processing vessel, a lining comprising: a mixture of mineral wool and a cementitious binder so proportioned as to promote impregnation of the lining with particles liberated from petroleum vapors undergoing a cracking process in .the vessel.

2. In combination with a petroleum processing vessel, a lining comprising: a mixture of mineral wool, diatomaceous earth and portland cement proportioned to promote impregnation of the lining with particles liberated from petroleum vapors undergoing a cracking process in the vessel.

3. A combination of a petroleum processing vessel and a lining, the lining comprising a mixture of mineral wool and a cementitious binder impregnated with coke particles.

4. A combination of a petroleum processing vessel and a lining, the lining comprising a mixture of mineral wool and portland cement proportioned to provide intersticial spaces for accumulation of solid particles precipitating from petroleum being cracked in the vessel.

CHARLES L. NEWPORT. HERBERT 0. SMITH.