Line Heaters

Design Conditions Required | Sizing Info | Technical Info | Picture Gallery

KW International’s Water Bath Indirect Line Heaters have a proven track record in the oil and gas industry. With a variety of applications from heating of natural gas to the heating of sour crude they provide a dependable resource in processing petroleum products. Indirect heaters transfer heat to the process stream through a heat transfer medium surrounding both the firebox and the process flow coil. Water bath indirect heater has a temperature range of 60°F to 190°F.

Design Conditions Required

Gas Flow Rate MMSCF / Day
Well Shut In Pressure
Well Flowing Pressure
Sales Line Pressure
Oil Rate BBL / Day
Water Rate BBL / Day
Flowing Temperature
Specific Gravity
Sour Gas
CO2

Sizing Information

Sizing information is proprietary to KW International, please call 1-800-845-WIND or click here to submit a Sales Inquiry Form.

Technical Information

Heaters

The heating of natural gas, condensate and crude oil is an essential process step for nearly every oil and gas production lease or processing facility. Several types of heaters have been developed in order to accommodate the various applications. KW International offers the following types of heaters:

Water Bath Indirect Heaters
Salt Bath Indirect Heaters
Oil Bath Indirect Heaters
Steam Bath Indirect Heaters
Steam Generators

Indirect Fired Heaters

Indirect heaters transfer heat to the process stream through a heat transfer medium, surrounding both the firebox and the process flow coil. Variations are required in the equipment design and accessories furnished, depending upon the bath media and process requirements. Therefore, the four types of indirect heaters are distinguishable by the heat transfer medium they are designed to use.

Direct Fired Heaters

Direct-fired units are those in which the heat released is transferred directly across the firetube wall to the process fluid. The process fluid in the steam generator is water. The process fluid in direct-fired heaters can be crude oil, crude-oil water emulsions, aqueous amine solutions, etc. The shells of these units are designed as pressure vessels under either Section IV or Section VIII, Division I, of the ASME Code. Section IV of the ASME Code applies only to steam generators that operate in the 0-15 pounds pressure range.

All heaters have two basic elements - a shell and a firebox. Indirect heaters have a third element, which is the process flow coil. All heaters have standard accessories such as burners, regulators, relief valves, thermometers, temperature controllers, etc. Optional accessories are available.

Heater Shell

The heater shell consists of a steel cylinder, flanged on both ends with two saddle-type supports. It has a fill connection on the top centerline and a drain connection on the bottom. A fuel gas preheat coil is installed along one side of the shell. Connections are also provided in the shell for a thermometer and a temperature controller. The heater shell is the basic vessel into which the firebox and coil are assembled. It holds the water bath, which surrounds both the firebox and coil. The flow coil and firebox are inserted into the shell from opposite ends, thereby facilitating their removal and replacement without interfering with each other.

The Firebox

The firebox normally consists of single or multiple “U” shaped firetubes fabricated from heavy-wall pipe. When assembled, it is in the lower portion of the shell, positioned on one of the removable flange end plates. This assures that the heat released in the firetube will be transferred to the water in the lower part of the heater, causing thermal circulation of the bath. All welded joints in the firetube are made by approved welding procedures and carefully inspected to assure high quality.

The Coil

The flow coil is the only portion of the heater that operates under more than atmospheric pressure. Flow coils are fabricated from seamless pipe and in strict accordance with API Specification 12K. The flow coils are attached to their flange plate so that the entire coil is above the firebox. This places the coil in the hottest portion of the water bath, thereby assuring rapid and efficient heat transfer. The surface area for heat transfer is carefully balanced with the firebox output to assure the transfer of the rated heat capacity. The coil consists of a series of straight tubes connected with 180o return bends to form a continuous path for the process fluid.

Water Bath Indirect Heaters

Water bath indirect heaters have a long history of successful application in the oil and gas industry. They have been applied to a variety of operations, ranging from the heating of natural gas to the heating of sour crude. The heater consists of three basic elements - the firebox, shell, and flow coil. These elements are carefully designed for each standard size. The firebox is designed to rapidly transfer the heat released by the burning fuel to the water bath. The flow coil is designed to safely contain the process fluid and transfer the required heat from the water bath to the process streams. A variety of coils are available for each firebox size, to allow a selection for the most economical and efficient combination.

Applications

Water bath indirect heaters have been used for a wide variety of applications in the oil and gas industry. A few of the more common applications are as follows:

Heating natural gas prior to regulation to prevent the formation of frost rings around the buried line downstream of the regulation station. This prevents ground heaving and pavement buckling.
Heating high-pressure natural gas prior to pressure reduction to prevent the formation of natural gas-water hydrates in the line downstream of the choke or regulator.
Heating a natural gas-condensate wellstream prior to separation, with or without an associated pressure reduction, so as to control the separation temperature, prevent the formation of hydrates, and assure good gas-liquid separation.
Heating of crude oil to maintain its temperature above the paraffin pour-point and to reduce its viscosity for easier handling in further lease processing.
Heating a natural gas wellstream to maintain it above its hydrate-forming temperature from the well to the processing point even though reduction of wellstream pressure is minimal.

Sales Features

Specifically designed to heat gases or liquids safely, over a wide range of pressures, without resorting to a high-pressure shell or a special design for each application.
Combustible fluids are heated in a flow coil by the hot water bath, completely isolated from the firebox.
The firebox is always immersed in fresh water, resulting in long life and elimination of coking and burnout problems. A clean metal surface rapidly transfers the firebox heat to the water bath.
A low tube-wall temperature of the flow coil, resulting from the uniform heating of the water bath, reduces scaling inside the flow coil. Hot spots will not develop to cause coil failure.
The entire flow coil is positioned above the firebox in the hottest portion of the water bath.
A wide range of interchangeable flow coils are available for each size of heater. This allows the easy selection of proper coil arrangement to satisfy heat transfer surface area and pressure drop requirements. Coils can be fabricated in accordance with Section VIII, Division 1, ASME Code, if requested.
Flow coils can be easily changed out of a heater to satisfy changing field conditions or applications, since they are supported independently of the firebox.
There are no intervening baffles or obstructions between the firebox and flow coil to restrict the rapid movement of thermal convection currents in the water bath.
The vapor conservation hatch cover on the shell minimizes water vapor losses, assuring a minimum of water make-up and a safe water level. The volume of the water bath has been kept to a minimum to provide rapid heat transfer.
Fuel gas preheat coils are incorporated in the heater to prevent fuel line freeze-up when large pressure reductions are required across the fuel gas regulator.
Burner and pilot light assemblies are specifically designed to match the firebox capacity and to provide safe, dependable, and efficient operation even under varying loads and adverse weather.
Controls, parts, and accessories are selected for dependability, safety, and simplicity. These enable the heater to operate unattended for long periods of time and in adverse weather.
A wide range of standard firebox ratings are available starting at 250,000 BTU/hr.
A broad selection of optional accessories are available to improve operations and to meet specific customer requirements, such as: flame arrestors, long-nose adjustable chokes, pressure regulators, fuel gas safety shut-off valve, fuel gas "Safe-Trap", shell insulation, pilot light safety shut-down control, etc.
Indirect heaters are designed in accordance with API Specifications 12K.
Firing controls, burner design, and firebox surface area are carefully matched to provide maximum thermal efficiency and energy conservation consistent with best engineering principles.
The heaters are Ideally suited for offshore and remote locations because of inherent safety and dependability. Numerous units are currently operating on offshore platforms and isolated locations.
Burner, fuel gas manifold, and controls are pre-piped in the shop prior to shipment to eliminate shortages and to facilitate field hook-up.
Heaters can be housed easily with only slight modification.

How It Works

Fuel gas is burned within the horizontal "U"-shaped firebox immersed in the lower portion of the water bath. Heat released by the burning fuel gas is quickly transmitted through the firebox wall to the water bath, maintaining it at the desired temperature.

The fluid to be heated (wellstream, natural gas, oil, water, etc.) is conducted through the flow coil of the heater which is immersed in the upper portion of the water bath. Heat is transmitted from the hot water bath through the tube-wall to the fluid inside the flow coil.

The heater temperature controller maintains the water bath temperature at the desired level by controlling the firebox fuel gas supply. A temperature of 190°F is considered the optimum temperature at which the bath of this type heater should operate. At temperatures above 190°F, water loss can be expected to increase. A water bath temperature of 190°F provides the designer with the temperature to use in MTD calculations for an optimized coil selection. Heaters in service can be and should be operated at water bath temperatures less than 190°F when inlet condition and/or outlet temperature requirements allow.

Operating the bath temperature at the minimum temperature required to give hydrate protection in either the pipeline or separator not only saves fuel, but provides maximum liquid recovery in the downstream equipment.

Standard Components and Accessories (subject to change without notice):

KW International Flame Arrestor
1 - Flanged cylindrical heater shell
1 - Removable "U"-bend type firebox w/cover plate
1 - Firebox stack
1 - Removable wellstream flow coil w/cover plate. Coil connections are either screwed or beveled for welding.
1 - Fuel gas preheat coil
1 - High efficiency burner w/pilot light
1 - Fuel gas manifold (pre-piped in shop)
Fuel gas "Safe Trap" with internal high level safety shut down valve
Fisher 630 "Big Joe" Regulator
Fisher 620 Regulator
1 - Low pressure strainer and drain valve
1 - Main fuel gas line block valve
1 - Pilot gas block valve
1 - 2" Dial face 0-60 psig pressure gauge with isolating valve
1 - Lot of pipe, pipefittings, copper tubing and tubing fittings for hookup
1 - Thermostat
1 - Diaphragm operated fuel gas control valve
1 - 3" Dial face thermometer, 20-240 F
1 - Low pressure fuel gas regulator
1 - 8" Vapor conservation, pressure/vacuum vent valve for shell fill connection
Paint: One coat of standard primer and one coat of pallet tan

Optional Accessories and Design Features:

KW International Down-draft Diverter
KW International Stack Arrestor
High bath temperature shutdown thermostat
Diaphragm operated fuel shutdown valve
Energy conserving shop-installed fiberglass shell insulation with aluminum jacketing and vapor barrier.
Pilot flameout safety shut down control
Short nose chokes (fixed orifice, manual hand wheel, or pilot and diaphragm operated)
Long-nose adjustable choke (manual hand wheel or pilot and diaphragm operated)
Special wellstream coils of required size, including multi-pass and working pressures in excess of 10,000 psig. Connections may be flanged, beveled for welding, screwed, or special end.
Shop-installed choke and piping tie-across between coil passes. Welded-in (non-removable) flow coils and/or fireboxes.
Structural steel skid and shop skid mounting.
Special paints and coatings

Water Bath Indirect Heaters: Sizing

Several general considerations must be reviewed before proceeding to the sizing problem, as they can have an appreciable effect upon the final heater selection. These considerations are as follows:

Natural gas hydrate formation
Joule-Thompson Effect (temperature drop verses pressure drop)
Choke type and installation
Use of antifreeze compounds
Use of corrosion inhibitors
Use of energy-saving shell insulation

Some of these are involved only with natural gas heating problems; i.e., natural gas hydrates and the Joule-Thompson Effect. The others can apply also to crude oil heating problems

Natural Gas Hydrates

Natural gas hydrate formation is a phenomenon that is encountered with high-pressure wellstreams and causes freeze-up and line plugging at temperatures well above 32F. Hydrates are very similar to snow in appearance. The following guidelines are given:

The wellstream must have free-water present and in contact with the natural gas before hydrates can form.
The wellstream must be near the predicted hydrate formation temperature for a given pressure.

Natural gas hydrates are very loosely linked compounds of the natural gas components and water vapor. However, there are known instances where hydrates have been encountered at temperatures as much as 10 above and below those predicted.

Natural gas hydrates are particularly troublesome in pipelines and gas process equipment. They can cause flow stoppage, reduce line capacity, and cause physical damage. Slugs of gas hydrates moving through a pipeline at normal gas velocities can produce high impact forces on valves, orifice plates, strainers, and other equipment that impede their movement. Hydrate slugs traveling from the line into scrubbers, separators, and compressors can likewise cause serious internal structural damage. Therefore, natural gas hydrates must be avoided to maintain flow. Each sizing problem should have both the inlet and the outlet conditions checked.

Joule-Thompson Effect

Another phenomena encountered with high-pressure natural gas wellstreams is the Joule Thompson Effect. A reduction in wellstream temperature occurs when the wellstream pressure is rapidly reduced, such as when the wellstream passes through a choke or specially designed control valve. This is referred to as the Joule-Thompson Effect or auto-refrigeration effect. It is probable that in reducing to sales line pressure; this effect will lower the wellstream temperature into the region of hydrate formation. Each application must be reviewed to determine the Joule-Thompson Effect. The temperature downstream of a choke can be predicted with reasonable accuracy using the upstream temperature, the initial pressure, and the final pressure. If the wellstream has more than 10 bbl/mmscf, the temperature drop across the choke due to pressure reduction should be reduced 5 F for each additional 10 bbl/mmscf.

Choke Installation

Chokes are specially designed valves for handling high differential pressures across the seat and stem. They are manufactured in two basic types, differentiated from each other by the body style; i.e., the "Long-Nose Choke" or long body style, and the "Tee Type Wing Value" or short body pattern. The long-nose choke was developed for use with the water bath indirect heater. The long body extension between the side inlet and the bottom outlet allows a portion of the choke to be immersed into the hot water bath. This places the seat of the choke where it is warmed by the hot water bath, keeping hydrates melted-out of the choke. The "Tee Type Wing Valve", or short body pattern choke, is normally the choke used on wellheads, on inlet lines to separators, and on heater coil outlets, etc. With this choke, the wellstream must be preheated sufficiently to prevent formation of hydrates immediately downstream of the choke; otherwise, problems will be encountered with hydrate plugging and freeze-off.

The location of the pressure-reducing choke will affect the selection of the flow coil. If the inlet gas pressure is 2000 psig or less, it is normally advantageous to install the choke on the inlet of the heater which results in a lower gas temperature in the flow coil. This takes advantage of a larger temperature differential between the gas and the hot water bath. The coil area is inversely proportional to the mean temperature difference. Mean temperature difference is the logarithmic average temperature between the water bath and the inlet and outlet temperatures of the process stream. Therefore, the required area would be less than if the pressure reduction were taken on the heater outlet.

The area required with the choke on the inlet is less than half that required with the choke on the coil outlet. Additional cost savings can be achieved by using a lower pressure-rated coil downstream of the choke. For example, a 2" standard weight coil could be substituted for a 2" XHy coil.

It is normally necessary, when the inlet gas pressure is above 2000 psig., to preheat the wellstream ahead of the pressure reducing choke. The flow coil, in this case, would be a split or double-pass coil with two inlets and two outlets extending through the cover plate. The long-nose choke is installed on the inlet to the second pass. The outlet of the first pass is piped to the side connection or inlet of the choke. There are two advantages to this arrangement: (I) A larger MTD is utilized to keep the surface area smaller; (2) The cost can be reduced by using a lower working-pressure pipe for the second pass.

Antifreeze Compounds in the Water Bath

It is quite common to put antifreeze compounds in water bath heaters to prevent physical damage to the unit in the event of pilot light, burner, or fuel system failure. The dependability of the controls and accessories furnished by KW International is excellent, but this does not rule out the possibility of a malfunction. Ethylene glycol is the most prevalent antifreeze in use today. The maximum concentration should never be higher than 50% glycol by volume. However, the use of ethylene glycol must be considered when sizing the coil because the increased viscosity and change in other bath properties results in a lower over-all heat-transfer coefficient commonly called "U" factor. For a 50% glycol solution, the "U" factor can be reduced as much as 20%. This requires a proportional increase in surface area of the coil with the same bath temperature. There is one compensating advantage - the bath temperature can be raised to 220 F (sea level) without boiling. The higher available MTD partially offsets the reduction in heat transfer coefficient.

Corrosion Inhibitors

Most ethylene glycol solutions marketed today contain corrosion inhibitors. The corrosion inhibitor should be replaced annually. Heaters containing only fresh water should have a corrosion inhibitor added on an annual basis. The pH should be periodically checked to keep it in the neutral or slightly basic range (pH of 7 or 8). There are a number of compounds, which may be used as corrosion inhibitors. KW International will recommend a suitable compound upon request. Corrosion inhibitors do not influence the sizing or selection of the flow coil. They aid in reducing scaling and maintaining a clean transfer surface on both the firebox and the coil. This will prolong the life of the heater.

Energy-Saving Shell Insulation

The present-day emphasis on energy conservation has developed new interest in insulating heater shells to conserve fuel and lower operating costs. Heat losses from a water bath indirect heater are normally estimated as equal to 10% of the required process heat. In northern regions and higher elevations, the loss can be as high as 20% of the process heat. Insulating the shell with 1-1/2 inches of a dense fiberglass blanket and covering with an aluminum jacket with a vapor barrier can reduce this loss to less than 1% of the required process heat. This amounts to an appreciable savings in operating cost. Lease operators are encouraged to insulate their units.

Oil Bath Indirect Heaters

Oil bath indirect heaters are specially designed units, which take advantage of other heat transfer media to heat natural gas and other process fluids to the range of 250F to 400F. Heat transfer medias or "oils" such as; Mobiltherm, Hydrotherm, Dowtherm, Therminol, etc. having low vapor pressures at temperatures up to 550F can be utilized effectively in units similar to water bath indirect heaters without resorting to pressure retaining shells.

Oil bath indirect heaters are designed to operate with both the flow coil and firebox immersed in the heat transfer oil. Since heat transfer oil has some vapor pressure and expands at temperatures in the 450F to 550F range, an expansion tank is furnished to allow full utilization of the shell for the flow coil and keeps exposure of the hot oil to the atmosphere at a minimum. Careful consideration must be given to the vapor pressure and thermal expansion characteristics of the heat transfer oil when designing the heater. It is necessary; therefore, to know which heat transfer oil is to be used by the customer. Units are designed, sized, quoted, and fabricated upon application because of the variance in media used and process requirements.

Oil bath indirect heaters are similar to water bath indirect heaters in that they are closed heating systems, requiring little make-up, and having the same three basic components: shell, firebox, and coil.

Applications

Reboiler for gasoline or light hydrocarbon stabilizers or fractionators such as those used with low-temperature separation units or small gasoline plants.

A process heater for heating a natural gas stream or refinery gas stream prior to further processing. It is possible to heat the gas stream up to 400F.

A process heater for petrochemical plant units. Would be suitable for temperature-sensitive organics, which require uniform heating and control of the maximum temperature to prevent decomposition.

Preheating waxy hydrocarbon liquid prior to processing.

Features

Designed to heat gases and liquids safely with hot oil, over a wide range of pressures at temperatures ranging from 250F to 400F without resorting to direct firing or to a high pressure shell.

The single or multiple "U" shaped fireboxes are specifically designed to always operate immersed in the heat transfer oil and with a moderate flux to assure long life, freedom from coking, and burnout.

The fireboxes are removable for periodic inspection of firebox and shell.

The flow coils are custom designed to provide the required heat transfer area at minimum cost. Flow coils are positioned above the firebox in the hottest portion of the oil bath to assure rapid heat transfer.

Flow coils are removable for periodic inspection and cleaning, if required. Uniform tube-wall temperature, as a result of being immersed in the hot oil bath, reduces the possibility of inside scaling and coking of the coil.

Burner and pilot light assemblies and fuel gas manifold assemblies are designed and field-proven to match the firebox capacity. Components are carefully selected to provide safe, dependable, and highly efficient operation under varying loads and adverse weather.

Units are furnished with 3" minimum insulation and aluminum jacketing with vapor barrier to conserve heat and to protect personnel.

A wide selection of optional accessories are available as extra-price items, such as: flame arrestors, fuel gas "Safe-Trap", stack arrestors, flow coil outlet temperature controller, pilot light flame-out shut-down, fuel gas regulators, etc.

Standard Components and Accessories

KW International Flame Arrestor

1- Removable firebox

1- Wellstream flow coil removable with screwed or beveled-for-welding end connections.

1- Stack

1- Expansion tank

1- Shell with one end flanged and the other with coil manway

1- High efficiency burner w/pilot light

1- Fuel gas manifold (pre-piped in shop)

Fuel gas "Safe-Trap" with high-level safety shutdown

Fisher 630 "Big Joe" Regulator

Fisher 620 Regulator

1- Low pressure strainer and drain valve

1- Main fuel gas line block valve

1- Pilot gas block valve 1-2" Dial face, 0-60 psig pressure gauge with isolating valve

1- Lot of pipe, pipefittings, copper tubing and tubing fittings for hook-up

1- Temperature controller w/separable socket

1- Diaphragm operated fuel gas control valve

1- High temperature shutdown thermostat w/separable socket

1- 3" Dial face thermometer, 50 -500 F

1- Low-pressure fuel gas regulator

1- 8" Vapor conservation, pressure/vacuum vent valve

Paint: One coat of standard primer Insulation: Shop installed 3" thick energy conserving, insulation and aluminum jacketing with vapor barrier.

Optional Accessories and Design Features

KW International Down-draft Diverter

KW International Stack Arrestor

Pilot flameout safety shutdown control

Short nose chokes (fixed orifice, manual hand wheel, or pilot and diaphragm operated)

Special wellstream coils of required size, including multi-pass and working pressures in excess of 10,000 psig. Connections may be flanged, beveled-for-welding, screwed, or special end.

Shop installed choke and piping tie-across between coil passes

Welded-in (nonremovable) flow coils and/or fireboxes

Structural steel skid and shop skid mounting

Special paints and coatings

Heat transfer media or oil

Special insulation per customer specification high temperature thermostat

High temperature thermostat w/diaphragm operated fuel gas shut-off valve

Salt Bath Indirect Heaters

Salt bath indirect heaters are similar to both the water bath and steam bath indirect heaters in that they have the same three basic Components- shell, firebox, and flow coil. Instead of fresh water as the heat transfer medium as is the case with the water and steam bath units, the salt bath heater uses a chemical salt. The flow coil and the firebox are immersed in the molten salt with the firebox in the lower or bottom section of the shell and flow coil in the upper section.

The operating temperature range of the chemical salt bath is 400F to 800F. This elevated lower limit is necessary as the salt itself is a solid crystalline material and does not begin to melt into a liquid until it is heated to 288F. Since oil bath indirect heaters can be used to heat streams up to 400F the normal application of the salt bath heater would be where required outlet stream temperatures are from 400F to 750F.

For outlet stream temperatures in the range of 350F to 400F either an oil bath or a salt bath heater could be used. However, a salt bath heater is more costly than an oil bath heater because of the type of construction required; they are larger for any given heat output size; and the salt is more expensive than heat transfer oil.

Applications

Regeneration gas heaters for dry bed adsorption units designed either for dehydration or hydrocarbon recovery duty where regeneration temperature above 500 F is required.

Reboilers to furnish bottom heat for stabilizers or liquid fractionators where elevated temperatures are required.

Features

Straight thru firetube construction eliminates the need for the "floating stack" used in conventional salt bath heaters.

Firetube design provides more efficient utilization of firetube area for heat transfer to salt.

Expansion bellows on each end allow for differential expansion between shell and firetube during start up.

Carbon steel flow coils in salt bath isolates the fluid being heated from the source of heat, eliminating hotspots and providing a "safe heat" feature.

Three inch thick fiberglass insulation with aluminum jacket and vapor barrier.

Salt fill hatches with insulated removable cover.

Salt drain connection (plugged).

How It Works

Fuel gas is burned within the straight thru firetubes. The heat released by the burning gas is quickly transferred through the firetube wall to the molten salt. Because of its high thermal conductivity, the molten salt efficiently passes the heat into the flow coil thru conduction and convection. As the process stream (liquid or gas) passes thru the flow coil, it picks up heat thru the coil wall. The temperature of the stream being heated can be controlled by setting the required bath temperature, or by controlling the temperature of the stream itself. Protection from overheating the bath and/or the process stream is provided by a high temperature shut-down controller located in the salt bath.

Standard Components and Accessories

KW International Flame arrestors (one on each firetube)

1- Insulated and jacketed shell.

1- Custom designed straight thru firebox w/expansion joints (also may be more than one fire tube).

1- Custom designed flow coil fabricated from seamless pipe with beveled-for-welding ends.

1- High efficiency burner w/pilot light (1 set for each firetube).

1- Stack (1 for each firetube)

1- Fuel gas manifold (pre-piped in shop) with:

1- High pressure fuel gas regulator

1- Fuel gas "Safe-Trap" with internal high-level safety shutdown valve.

1- Low pressure strainer and drain valve

1- Main fuel gas line block valve

1- Main pilot gas line block valve

1- 2" dial 0-60 psig pressure gauge as isolating valve

1- Lot of pipe, pipefittings, copper tubing, and tubing fittings for hookup

1- Thermostat for bath temperature control w/separable socket

1- Thermostat for high bath temperature override w/separable socket

1- Diaphragm operated fuel gas shut-off and control valve

1- 3" dial thermometer 200-1000 F with thermowell

1- Low-pressure fuel gas regulator

2- 20” dia. salt fill hatches w/covers (3 in larger units)

1 set- 3" fiberglass insulation w/aluminum jacket and vapor barrier

Optional Accessories and Design Features

KW International Down-draft diverter (one on each stack)

KW International Stack arrestor (one on each stack)

1- Pilot failure safety shutdown 1-Separate diaphragm operated fuel gas shut-off valve for pilot failure and/or high bath temperature.

1 set - special heating coils per customer's requirement w/flanged ends

1- structural steel skid including mounting heater on skid w/pre-piping as required

Steam Generators

Steam generators were developed to provide a source of low-pressure steam for heating crude oil tanks and other lease heating requirements. They consist of only a shell and a firebox. They can be used to supply steam to heat exchangers in the crude production line, heating coils in storage tanks, heating coils in emulsion treating tanks, and even for heating buildings and offices on the lease. They are particularly advantageous when multiple heat loads can be consolidated and supplied by one highly efficient central heat source.

Most of the systems using steam generators are closed systems with very little make-up water required. They can be used on open systems with additional equipment such as boiler feedwater controller, blow-down system and feedwater treatment units. These are necessary to prevent scale formation and to assure that steam losses are made up.

Applications

A source of steam to heat an emulsion treater or to heat a coil in a treating tank where corrosive crudes are processed.

A source of steam to heat an emulsion treater or to heat a coil in a treating tank where the possible source of ignition must be located remotely from the process area.

Central steam heating source for a battery of crude oil emulsion treaters. This method improves overall thermal efficiency of installation and saves energy.

Central steam heating source for offshore platforms where sources of ignition must be located away from the production equipment.

A source of steam to heat small buildings and offices.

A source of steam for heat exchanging with natural gas or crude oil wellstream prior to further processing.

A source of steam for heating the reboiler or bottom section of a low-pressure stabilizer or fractionator.

How it Works

Fuel gas is burned within the horizontal "U" shaped firebox immersed in fresh water. Heat released by the burning gas is quickly transmitted through the firebox wall to the water bringing it up to its boiling point and evaporating it to form saturated steam.

Normally, this steam is then piped to a heat exchanger or coil where it is used to heat a gas, liquid, or solid, depending upon the application. Here, the steam loses its latent heat of vaporization and condenses. The condensate returns to the steam generator where it enters at the bottom and is reheated to form more steam.

As steam is formed in the steam generator, the temperature increases until it reaches the desired maximum level, at which time the pressure stat shuts off the fuel supply to the firebox. As the steam is condensed in the outside heating system, the temperature begins to lower and the pressure stat correspondingly opens the fuel gas line to the burner, producing more steam.

A low water level safety shut off is furnished to shut off the fuel gas in event the steam generator water level drops below the safe operating level. Energy saving insulation is furnished as a standard item.

Steam Generator Sizing

The sizing of steam generators requires determination of the process heat load. Select a unit having a firebox capacity equal to or greater than the required heat load. Sizing of the heat exchanger or equipment used to transfer the steam heat to the process should be referred to the engineering department or to the heat exchanger manufacturer.

Standard Components and Accessories

KW International Flame Arrestor

1- Removable firebox

1- Section IV, ASME Code shell

1- ASME steam relief valve

1- Stack

1- High efficiency burner w/pilot light

1- Fuel gas manifold (pre-piped in shop)

Fisher 620 Regulator

Fisher 630 "Big Joe" Regulator

Fuel gas "Safe-Trap" with high-level safety shut-down

1- Low pressure strainer and drain valve

1- Main fuel gas line block valve

1- Pilot gas block valve

1- 2" Dial face 060 psig pressure gauge with isolating valve

1- Lot of pipe, pipefittings, copper tubing and tubing fittings for hookup.

1- Low water level safety shut-off

1- Liquid level gauge

1- Pressure stat

1- Diaphragm operated fuel gas control valve

1- Steam pressure gauge w/siphon lead and isolating valve

1- Fuel gas preheat coil

1- Fuel gas regulator

1- Set of energy conserving, shop installed, fiberglass shell insulation w/aluminum jacketing and vapor barrier

Paint: One coat of standard primer and one coat of aluminum

Optional Accessories and Design Features

KW International Stack Arrestor

KW International Down-draft Diverter

Pilot flameout safety shut-down

Automatic water make-up controller (boiler feedwater control) Blow-down system

Low water level safety shut-off

Structural steel skid and shop skid mounting

Special paints and coatings

Direct Fired Heaters

Direct-fired heaters are generally used in multi-unit oil treating systems either to heat the crude oil wellstream direct or to maintain a hot water wash system in a gun barrel-treating tank. They have also been used on oil pipelines as suction heaters to reduce the crude oil viscosity and improve the pump performance.

The unit consists of a pressure vessel shell and a removable firebox.

Applications

Heating crude oil wellstreams prior to entering a gun barrel or treating tank.
Heating circulating water or naturally produced brines in a thermo siphon heating system for a gun barrel or treating tank.
Heating crude oil from storage tank prior to pumping into a pipeline to keep paraffin in solution, or to improve pump efficiency by reducing viscosity.
Use as a portable heater for tank clean up, or to heat and circulate tanks before transferring into the pipeline

Features

Easy to install, hookup, and maintain.
Firebox is removable to facilitate periodic inspection and cleaning without disturbing the flow line to and from the heater.
Smooth rounded firebox surface discourages deposition and accumulation of sediment, providing long life and high efficiency.
Sturdy shell and support construction of horizontal types permit these units to be either skid mounted or trailer-mounted for use as a portable lease heater. The horizontal's low silhouette, removable stack, plus simple, rugged, and dependable controls are additional reasons why these units are ideal portable heaters.
Burner and pilot light assemblies are carefully designed and selected to match the firebox capacity and provide dependable efficient operation even in adverse weather.
Temperature controls and other accessories are specifically selected for accurate, dependable, and trouble-free operation.
Wide range of standard firebox ratings available, starting at 250,000 BTU/Hr.
Full length inlet liquid distributor assures uniform distribution of the fluid the full length of the firebox. The result is uniform heating of the fluid without channeling or hot spots

How It Works

Fuel gas is burned within the horizontal "U"-shaped firebox immersed in the liquid to be heated. Heat released by the burning fuel gas is quickly transmitted through the firebox wall to the liquid. The liquid to be heated enters the heater through the inlet distributor, which releases it uniformly throughout the length of the firebox and immediately below the firebox. The liquid is carried upward by the thermal convection currents and is heated by the heat released from the firebox the temperature controller maintains the liquid temperature at the desired setting by controlling the fuel gas supply to the burner assembly. The heated liquid leaves the heater through the connection on top of the unit.

Note: Operation of vertical direct-fired heater is the same except for shell configuration.

Direct Fired Heaters Sizing

Sizing of direct-fired heaters requires only the determination of the process heat load so that a firebox capacity can be selected. Process heat load calculations for other fluids should be referred to the engineering department for recommendation. Add 10% to the process heat load for the uninsulated shell losses and then select a unit with a firebox capacity equal to or greater than the total heat load.

Standard Components and Accessories

KW International Flame Arrestor
1- Removable firebox
1- Heater shell, Section VIII ASME Code
1- Stack
1- High efficiency burner w/pilot light
1- Fuel gas manifold (pre-piped in shop)
Fisher 630 "Big Joe" Regulator
Fisher 620 Regulator, Energy conserving, shop installed, fiberglass shell insulation with aluminum jacketing and vapor barrier
Fuel gas "SafeTrap" with internal high-level safety shutdown valve.
1- Low pressure strainer and drain valve
1- Main fuel gas line block valve
1- Pilot gas block valve
1- 2" Dial face 0-60 psig pressure gauge with isolating valve
1- Lot of pipe, pipefittings, copper tubing, and tubing fittings for hookup
1- Thermometer, 3" dial face 20-240F w/ss socket
1- Inlet distributor pipe
1- 3" Dial face 0-50 psig pressure gauge w/isolating valve
1- Fuel gas preheat coil
1- Fuel gas regulator
1- Thermostat w/separable socket
1- Diaphragm operated fuel gas control valve
Paint: One coat of standard primer and one coat of pallet tan topcoat

Optional Accessories and Design Features

KW International Down-draft Diverter
KW International Stack Arrestor
Pilot flameout safety shutdown
Low-level safety shutdown
High temperature safety shutdown thermostat with separable socket (high temperature safety shut-down.)
High temperature safety shut-down thermostat w/separable socket and diaphragm operated fuel gas shut-down valve
Hinged stack w/tie-down and support (On horizontal portable units) Structural steel skid and shop skid-mounting Trailer and trailer mounting Special paints and coatings

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Cut-Away View