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10 Ways to Minimize Grate Wear in a Waste-to-Energy Boiler

Thermal and mechanical grate wear increases maintenance costs. If the grate is not operated correctly, or if combustion is not properly managed, wear accelerates and there is risk of substantial damage. As a fuel, waste tends to be unpredictable and varies over time. It presents challenges for the plant, and can cause mechanical, thermal and chemical wear.

Reagent Preparation and Dewatering in a Wet FGD System

If limestone consumption must be increased to improve SO2 removal, the reagent preparation and dewatering systems may be undersized. In most cases, higher SO2 removal requires a finer grind than what older systems were originally designed to achieve.

Bid Evaluation Example

The example below provides a comparison between two industrial boiler bids where one bidder has a higher price but with a unit that has higher efficiency. Bid 1 guarantees 86.5% efficiency with a price of $10,400,000. Bid 2 guarantees 87.5% efficiency with a price of $11,200,000.

Limestone Forced Oxidation System Upgrades

A wet FGD can be converted to forced oxidation using the existing reaction tank, or in some cases, an external oxidation tank can be used. This conversion will minimize scaling from utilization of stable system chemistry and creating a saleable byproduct which will decrease disposal costs.

Mist Eliminators and Mist Eliminator Wash System

Older generation ME wash system designs tended to not effectively wash all surfaces of the MEs when compared to current designs. Fixed grid ME wash headers can be retrofitted in place of retractable lance-style wash systems or fixed grids that were ineffective in washing the ME surfaces.

Factors that Affect ESP Collection Efficiency and Ways to Improve Performance

This article will review several design and operational problems that will negatively affect the collection performance of an ESP. It will also outline potential modifications to help improve performance and efficiency.

Basics of Electrostatic Precipitator (ESP) Operation

Gas velocity between the plates is also an important factor in the collection process since lower velocities permit more time for the charged particles to move to the CEs and reduce the likelihood of migrating back into the gas stream (re-entrainment). A series of CE and DE sections is generally necessary to achieve overall particulate collection requirements.

Design for Constructability

Since construction costs for some projects can exceed 50% of a total project, the cost of labor presents both the greatest opportunity and greatest risk for almost any project. A design for constructability seeks to minimize impacts and improve productivity through the elimination of rework and/or corrective action, improve material deliveries, and incorporate some type of modularization.

Upgrades to Wet FGD Absorber Spray Headers

Spray header support systems are another area for potential upgrades. Older generation spray header designs used a support system that was prone to breakage which causes the header sections to fail and fall to the bottom of the absorber.

Boiler Operations That Affect Efficiency (Part 1)

Fuel is a major cost in boiler operation. It is therefore important to minimize fuel consumption and maximize steam production. Although a boiler’s efficiency is primarily a result of its design, the operator can maintain or significantly improve efficiency by controlling losses to the stack and losses to the ash pit.

A Numerical Modeling Example – Sorbent Injection Systems

To minimize the amount of sorbent used, it must be injected into the flue with a properly engineered lance that effectively disperses it into the gas, and the flow conditions in the flue must be sufficient for the particles to stay suspended for the required residence time to complete the desired absorption.

Engineered Approaches in Construction, and Construction Methods

Modern construction methods include modularized components that are erected on short timetables. To reduce construction and shipping costs, leaner designs of support steel components have become the norm. As a result, the calculation of imposed erection loads has become even more critical.

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