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4-3 Water head loss of filter课程教案、知识点、字幕

在上一节我们学习了快滤池的基本工作过程

而要深入了解过滤过程,就需要了解其中水头损失的变化

首先给大家介绍清洁滤料层水头损失的计算

在过滤开始时,滤层是干净的

水流通过干净滤层的水头损失称为清洁滤层的水头损失

或者称为"初始水头损失"

我们可以用这个公式进行计算

其中v是滤速,l_0是滤层厚度,m_0是滤料孔隙率

如果是非均匀滤层,则可按筛分曲线分成若干层

取相邻两筛子的筛孔孔径的平均值作为各层的计算粒径

计算各层水头损失,然后求和得到整个滤层的总水头损失

计算公式如这个式子所示

其中公式中的p_i为粒径为d_i的滤料质量占全部滤料质量的比例

过滤一旦开始,滤料层就会截留杂质,导致在过滤过程中水头损失发生变化

这个变化过程难以用理论公式进行描述

但可以通过设置测压管,来测定过滤过程中滤池各个部分的水头损失变化

这里,为了便于理解,假设在过滤周期内,滤池的水位和滤速都不变

滤池的总水头H可以由以下几部分组成

其中Ht代表滤料层的水头损失,由这两测压管的液位差进行计算

h_1是承托层和配水系统水头损失,由这两个测压管的液位差进行计算

第3项h_t代表出水滤速控制阀的水头损失

第4项是流速水头,第5项h_2为剩余水头

滤层的水头损失H_t可以进一步用清洁滤层水头损失H_0

加上t时刻的滤层水头损失增值△Ht来进行计算

下面,我们来看看在一个过滤周期中各项水头损失是如何变化的?

在某个时刻t,随过滤的进行,滤层中截留的杂质逐渐增加

导致滤层水头损失从清洁滤层的初始水头损失H_0增加到了H_t

但由于承托层和配水系统在整个过滤过程中基本上是干净的

只要滤速不变,h_1就不会发生变化

同时流速水头也不变

因此为了保持滤速不变

滤层水头损失从H_0到H_t的这部分增值只能通过调节出水滤速控制阀门来弥补

即控制阀门的阻力必须从原来的h_0减少到h_t,此时剩余水头h_2仍可保持不变

H_t随时间的变化曲线反映了滤层截留的杂质量与过滤时间的关系

这里我们假设H_t随时间呈线性增加

当运行到e点,出水滤池控制阀门阻力h_t变为最小值h_T

即控制阀全开时,滤层水头损失增加到了H_T

此时过滤时间为T,这就是过滤周期

如果此时继续过滤,则剩余水头h_2就要被开始动用

运行到m点,过滤时间达T'时

剩余水头h_2被全部消耗完,此时滤池达到最大允许水头损失

如果再继续过滤,过滤出水量就会减少

因此T'是滤池的最大可能过滤周期

但在实际运行中,过滤周期到T时滤池也就停止运行了

这节介绍了滤池过滤周期中水头损失的变化

下一节将介绍滤池的过滤操作方式

Water and Wastewater Treatment Engineering: Physicochemical Technology课程列表:

Chapter 0 Introduction

-0-2 Water treatment process

--0-2 Water treatment process

-0-3 Wastewater treatment process

--0-3 Wastewater treatment process

-Chap 0 Homeworks

Chapter 1 Coagulation and flocculation

-1-1 Introduction

--1-1 Introduction

-1-2 Properties of colloids

-- 1-2 Properties of colloids

-1-3 Mechanisms and process of coagulation and flocculation

--1-3 Mechanisms of coagulation and flocculation

-1-4 Coagulant and coagulant aids

-- 1-4 Coagulant and coagulant aids

-1-5 Kinetics of coagulation and flocculation

--1-5 Kinetics of coagulation and flocculation

--Announcement

-1-6 Factors affecting the coagulation performance

--1-6 Factors affecting the coagulation performance

-1-7 Facilities for coagulation and flocculation

--1-7 Facilities for coagulation and flocculation

-Chapter 1 Homeworks

Chapter 2 Sedimentation and clarification

-2-1 Introduction

--2-1 Introduction

-2-2 Discrete particle settling

--2-2 Discrete particle settling

-2-3 Flocculent settling

--2-3 Flocculent settling

-2-4 Zone settling

--2-4 zone settling

-2-5 Rectangular settling tank

--2-5 Rectangular settling tanks

-2-6 Process calculation of rectangular settling tanks

--2-6 Process calculation of rectangular settling tanks

-2-7 Vertical Flow (up-flow ) and radial flow settling tank

--2-7 Vertical Flow (up-flow ) and radial flow settling tank

-2-8 Plated sedimentation tank

--2-8 Plated sedimentation tank

-2-9 Clarification pool

--2-9 Clarification pool

-3D interactive demonstration for settling tanks

--Method for browser setting

--Up-flow settling tank

--Clarification pool

--Circular settling tank

-Chapter 2 Homework (part 1)

-Chapter 2 Homework (part 2)

Chapter 3 Air floatation

-3-1 Introduction

--3-1 Introduction

-3-2 Theoretical foundation of air floatation

--3-2 Theoretical foundation of air floatation

-3-3 Pressurized dissolved air flotation

--3-3 Pressurized dissolved air flotation

-Chapter 3 Homework

Chapter 4 Filtration

-4-1 Introduction

--4-1 Introduction

-4-2 Structure and process of conventional rapid filter

--4-2 Structure and process of conventional rapid filter

-4-3 Water head loss of filter

--4-3 Water head loss of filter

-4-4 Filtration method of filter

--4-4 Filtration method of filter

-4-5 Filter media

--4-5 Filter media

-4-6 Water distribution system

--4-6 Water distribution system

-4-7 Filter backwashing

--4-7 Filter backwashing

-4-8 Siphon filter

--4-8 Siphon filter

-4-9 Gravity valveless filter

--4-9 Gravity valveless filter

-4-10 Movable hood filter

--4-10 Movable hood filter

-3D interactive demonstration for filtration tanks

--Usage and description for 3-D demonstration

--Method for browser setting

--Conventional rapid filter

--Siphon filter

-Chapter 4 Homework

Chapter 5 Disinfection

-5-1 Introduction

--5-1 Introduction

-5-2 Influence factors of disinfection

--5-2 Influence factors of disinfection

-5-3 Chlorine disinfection

--5-3 Chlorine disinfection

--Correction

-5-4 Chlorine dioxide disinfection

--5-4 Chlorine dioxide disinfection

-5-5 Ultraviolet disinfection

--5-5 Ultraviolet disinfection

-Chapter 5 Homework

Chapter 6 Ion-exchange

-6-1 Ion-exchange resin

--6-1 Ion-exchange resin

-6-2 Properties of ion-exchange reactions

--6-2 Properties of ion-exchange reactions

-6-3 Properties of cation exchange resin

--6-3 Properties of cation exchange resin

-6-4 Properties of anion exchange resin

--6-4 Properties of anion exchange resin

-6-5 Softening system using ion exchange

--6-5 Softening system using ion exchange

-6-6 Desalination system using ion exchange

--6-6 Desalination system using ion exchange

-6-7 Ion-exchange equipment

--6-7 Ion-exchange equipment

-6-8 Treatment of industrial wastewater by ion-exchange method

--6-8 Treatment of industrial wastewater by ion-exchange method

-Chapter 6 Homework

Chapter 7 Membrane separation

-7-1 Introduction

--7-1 Introduction

-7-2 Principle and characteristics of electrodialysis

--7-2 Principle and characteristics of electrodialysis

-7-3 Configuration of electrodialysis unit

--7-3 Configuration of electrodialysis unit

-7-4 Operating parameters for electrodialysis unit

--7-4 Operating parameters for electrodialysis unit

-7-5 Principle and process of reverse osmosis

--7-5 Principle and process of reverse osmosis

-7-6 Operating parameters for reverse osmosis

--7-6 Operating parameters for reverse osmosis

-7-7 Principles and characteristics of UF and MF

--7-7 Principles and characteristics of UF and MF

-7-8 Design of ultrafiltration and microfiltration process

--7-8 Design of ultrafiltration and microfiltration process

-Chapter 7 Homework

Chapter 8 Redox method

-8-1 Fundamental knowledge and classification

--8-1 Fundamental knowledge and classification

-8-2 Ozonation

--8-2 Ozonation

-8-3 Photo-catalytic oxidation

--8-3 Photo-catalytic oxidation

-8-4 Supercritical water oxidation

--8-4 Supercritical water oxidation

-8-5 Electrolysis

--8-5 Electrolysis

-Chapter 8 Homework

Chapter 9 Adsorption

-9-1 Introduction

--9-1 Introduction

-9-2 Adsorption equilibrium and adsorption isotherm

--9-2 Adsorption equilibrium and adsorption isotherm

-9-3 Adsorption breakthrough curve

--9-3 Adsorption breakthrough curve

-Chapter 9 Homework

4-3 Water head loss of filter笔记与讨论

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