Energy
Heat Recovery Systems & Specialty Heat Exchangers (Pulp & Paper - Kraft)
Heavy Liquor Heaters
The Heavy Liquor Heater is a shell and tube unit with the liquor within the tubes. The unit may be installed in either a slightly inclined horizontal position or a vertical position.
Benefits of indirect black liquor heating are:
- Liquor temperature is maintained more closely than a direct unit, giving better combustion control.
- No dilution of the liquor with steam condensate, resulting in an increase in firing solids or evaporator/concentrator capacity.
- Allows recovery of the clean steam condensate.
- Minimization of risk in diluting the black liquor below the safe firing concentration.
Liquor re-circulation is utilized to maintain velocity within the heater at varying boiler operating rates. The additional pressure drop of the heater is taken up by the recirculation pump.
Options available include the use of Reynolds Enhanced Heat Transfer (REX) technology. REX inserts are spiral blades inserted through the length of each tube to promote turbulence at lower fluid velocities. Where applicable, this technology allows the total amount of recirculated flow to be reduced. Benefits include reduction in pumping horsepower by as much as 45% and improvements to fouling and scaling resistance.
Batch Blow Heat Recovery
The collection of the NCG from the digester blow requires the efficient condensing of the blow vapours without relief to the atmosphere or the intake of ambient air into the system. The batch blow releases a large amount of heat in a short time resulting in a high condensing water demand, thus most systems are direct contact condensing.
Our systems are designed to take a batch process and turn it into a continuous heat source. A system will include pressure and vacuum relief devices, a cyclone separator for removal of entrained fibre, a direct contact primary co-current condenser, an accumulator tank, an indirect secondary condenser, heat recovery, and a condensing water supply pump.
Vent Gas Heat Recovery
The A.H. Lundberg Vent Gas Heat Recovery System (HRS) provides high efficiency heat recovery from an industrial plant's waste gases normally vented to atmosphere. The system is applicable to flue gas as well as hot gases vented from process operations.
Digester Liquor Heaters
Heating the cooking liquor using external, indirect heat exchangers gives improved operation and reduced K# variability of the digester operation. Our Digester Liquor Heaters are vertical arrangement units specially designed to tolerate repeated thermal and hydraulic shock inherent in these services.
Kraft Continuous Digester Heat Recovery
For continuous digester systems, the heat is recovered from extraction liquor flash tanks and the steaming vessel. In mills pulping softwood, the continuous digester heat recovery system serves as the first stages to turpentine recovery.
Fiber is removed from the vapor using a cyclone separator and then the vapor is condensed either directly or indirectly. A shell and tube condensing system will be of counter-current design while a direct contact system will be two-stage with the first stage being a co-current direct contact condenser and the second stage is a counter-current shell and tube unit.
Chlorine Dioxide Heaters and Coolers
To reduce energy cost both for chilling the absorption water and heating the chlorine dioxide solution, A. H. Lundberg Systems recommends the use of heater exchangers to optimize energy consumption in the bleach plant.
Our Chlorine Dioxide Solution Heater will save on chilling capacity for water to the absorption tower by exchanging heat with the chlorine dioxide solution from the tower. The cold chlorine dioxide solution is heated by the incoming absorption water, consequently the water now going into the chiller is cooler and requires less chilling capacity. In addition, the chlorine dioxide solution is warmer, reducing steam requirement in the bleach plant. Our Bleach Plant Chlorine Dioxide Solution Heater is used to exchange heat between the chlorine dioxide solution and filtrates, reducing the steam demand in the bleach plant.
A.H. Lundberg Systems provides shell and tube units for these services, installed in a slightly inclined horizontal position, to accommodate safe removal of any gases released from the chlorine dioxide solution.
Surface Condensers
A.H. Lundberg supplies surface condensers for many different types of gases and operating conditions. Horizontal and vertical orientation designs are given consideration. Condensers may be designed on a stand alone basis or be integrated into a mass transfer column.
Our experience includes the design and supply of dirty steam condensers, foul condensate condensers, reflux condensers, organic vapour condensers, and condensers containing high percentages of non-condensible gases.