Ceramic Valves for Waste Incineration Desulfurization

Waste incineration desulfurization process flow

KOWOV ceramic valves are used in the desulfurization systems of waste incineration and waste-to-energy plants, where abrasive slurries and corrosive media challenge conventional valve performance. This application overview covers slurry control at reactors and atomizers, relevant operating conditions, and customer references for flue gas purification service

Flue Gas Treatment for Waste Incineration

Focus on Desulfurization

Operating Conditions

Unlike the conventional wet flue-gas desulfurization systems commonly used in coal-fired power plants, waste-incineration facilities may employ an atomized semi-dry desulfurization process. Ultrasonic atomization reduces the slurry droplet size from approximately 1,500-3,000 μm to 50-80 μm, producing a fine mist that significantly increases the gas-liquid contact area. This accelerates SO₂ absorption and improves desulfurization efficiency

However, high flow velocities and suspended solid particles intensify erosion and corrosion inside pipelines and valves, placing demanding requirements on valve materials, sealing performance, and service life

Operating Parameters

Item	Value	Item	Value
Medium	Lime slurry / alkaline absorbent slurry	Phase	Solid-liquid two-phase flow
Operating Pressure	6-16 bar	Nominal Pressure	PN16 / Class 150
Differential Pressure	≤6 bar	Nominal Diameter	DN25-DN200
Operating Temperature	<100°C	Thermal Conditions	No significant thermal shock
Medium Characteristics	Corrosive and abrasive	Solids Content	Approximately 25%

Medium Details

Lime slurry, chloride ions, fly ash, reaction products, and other suspended abrasive particles

Chemical Composition

Contains approximately 600 ppm chloride ions, creating a risk of electrochemical and localized corrosion

Solids Content

Approximately 25%, forming a high-solids solid-liquid two-phase flow

Particle Size

Approximately 10-100 μm. Fine particles intensify erosion of the valve internals and sealing surfaces

Unique Operating Challenges

Combined Erosion and Corrosion

High-velocity corrosive slurry containing suspended solids continuously impacts valve internals, damaging the protective oxide film and exposing the metal substrate. Mechanical erosion, chemical attack, and electrochemical corrosion act simultaneously, accelerating material loss and sealing-surface failure

Chloride-Induced Localized Corrosion

Dissolved chlorides and sulfates penetrate coating defects and attack the metal substrate. During shutdowns, evaporation and salt crystallization generate localized stresses, promoting pitting, cracking, blistering, and lining delamination. Repeated wet-dry cycling further accelerates this damage

Degradation of Non-Metallic Linings

Flue gas and slurry can cause rubber and resin linings to swell, soften, blister, crack, or delaminate through chemical degradation and media permeation. Once the lining is damaged, the underlying metal loses protection and corrodes rapidly

Acid Dew-Point Corrosion

Metal oxides in fly ash may promote the conversion of SO₂ to SO₃. When SO₃ combines with water vapor, sulfuric acid mist can form. If the operating temperature falls below the acid dew point, severe low-temperature corrosion may occur, especially in the presence of HCl and HF

More Severe Than Conventional Power-Plant FGD

Waste-incineration flue gas contains complex and highly variable components, including HCl, HF, SOₓ, fly ash, and heavy-metal salts. High dust loading, elevated moisture, chloride enrichment, and frequent wet-dry cycling make the operating environment more corrosive and abrasive than conventional coal-fired power-plant FGD service

Keywords: Waste Incineration, Semi-Dry Desulfurization, Lime Slurry Atomization, Chloride Corrosion, Abrasive Slurry, Wet-Dry Cycling, Acid Dew-Point Corrosion

Process Pain Points and Improvement Opportunities

Conventional Valve Materials and Types

Commonly used valves include globe valves, eccentric butterfly valves, and plug valves, typically manufactured from 316L stainless steel. More demanding services may require Hastelloy C-276, hard-seated plug valves, or ceramic-lined valves. However, conventional metal valves still experience rapid deterioration in highly abrasive and chloride-rich slurry service

Problems with Conventional Valves

Lime slurry contains highly abrasive suspended solids, while chloride-rich condensate creates a strongly corrosive environment. Their combined action causes erosion, localized corrosion, sealing-surface damage, internal leakage, and increased operating torque

Short Replacement Cycles

Based on typical field experience, conventional control valves may require replacement after approximately 6-10 months, while on-off valves may last only 12-30 months, depending on the valve position and operating severity

Losses Caused by Shutdown Maintenance

Reduced incinerator load or bypass operation lowers flue-gas treatment capacity and increases environmental compliance risks
Emergency maintenance, cleaning, temporary piping, and spare-parts replacement increase operating costs
Repeated flushing increases water, electricity, and chemical consumption
Frequent shutdowns and restarts accelerate thermal cycling and shorten equipment life
Reduced treatment capacity can restrict waste throughput and result in lost operating revenue

Industry Pain Points and Improvement Opportunities

Waste-incineration desulfurization imposes much higher requirements for corrosion resistance, erosion resistance, sealing reliability, and control accuracy than conventional power-plant FGD. Frequent valve failures have become a major obstacle to continuous and stable system operation, creating strong demand for improved valve materials and designs

Keywords: High Lifecycle Cost, Short Service Life, Frequent Maintenance, Environmental Compliance Risk, High Water and Chemical Consumption, Restricted Waste-Treatment Capacity

Why Choose Ceramic Valves?

Superior Abrasion and Erosion Resistance

Structural ceramics with hardness above HRA90 provide excellent resistance to abrasive slurry and high-velocity particle erosion
Their chemically stable, low-adhesion surfaces reduce particle buildup, galling, and surface fatigue

Superior Corrosion Resistance

Structural ceramics resist acids, alkalis, salts, and complex process liquids, greatly reducing chemical attack and pitting
Unlike metals, ceramics are not susceptible to electrochemical corrosion and offer excellent resistance to chloride-induced damage

All-Ceramic Trim Design

A smooth, dead-zone-free flow path reduces particle accumulation and valve blockage
The ceramic ball and seats maintain stable sealing geometry after prolonged erosion, providing reliable tight shutoff
Specially designed ceramic trim can provide equal-percentage or quick-opening flow characteristics for slurry control applications

Extended Service Life

Typical Reference Service Life: Control Valves: ≥3 Years
On-Off Valves: ≥7 Years

Longer service life reduces replacement frequency, unplanned downtime, spare-parts consumption, and overall lifecycle costs

Conclusion

Ceramic slurry valves address the combined challenges of corrosion, abrasion, erosion, and particle scouring. They have been successfully applied in waste-incineration flue-gas desulfurization systems, particularly in lime-slurry circulation and atomization-related pipelines, improving sealing reliability, service life, and plant availability

End Users

Yangzhou Domestic Waste Incineration Power Plant, China, since 2010
Kelin Environmental Resources (Suzhou) Co., Ltd., China, since 2021
Dongguan Jinghuan Environmental Protection Power Plant, China, since 2011
Tianjin Teda Environmental Protection Power Plant, China, since 2012

In the harsh working conditions of waste incineration desulfurization, the project initially selected imported single-seat valves, double-seat valves, and plug valves from renowned European and American brands. However, the limestone slurry is highly abrasive, and the high chloride ion flue gas and its condensate are highly corrosive. These factors cause severe internal and external corrosion and erosion of the valve, especially in the sealing surface, resulting in most metal valves failing after only 2-3 months of use, and some even failing within half a year

KOWOV ceramic valves have been operating stably in the desulfurization system of Huaibei Waste Incineration Power Plant for more than 5 years, fully demonstrating the excellent performance of ceramic valves in resisting corrosion, wear, and high-speed scouring. They have been successfully applied in key control positions such as reactors and atomizers, becoming the optimal choice for such working conditions

Conclusion: Actual Service Life