《大气污染防治原理》作业机翻

注：只有作业题目机翻，没有答案。

第1次作业

Fundamentals of Air Pollution Engineering

2.2

A high-volatile bituminous coal has the following characteristics:

高挥发分烟煤具有以下特点：

It is burned in air at an equivalence ratio of 0.85. 500 × 10⁶ W of electric power is produced with an overall process efficiency (based on the input heating value of the fuel) of 37 %.

它在空气中以0.85的当量比燃烧。产生500 × 10⁶ W的电力，整体工艺效率（基于燃料的输入热值）为37%。

(a) Determine the fuel and air feed rates in kg s^-1.

确定以kg s^-1为单位的燃料和空气进料速率。

(b) Determine the product gas composition.

确定产品气体成分。

(c) Sulfur dioxide is removed from the flue gases with a mean efficiency of 80% and the average output of the plant is 75% of its rated capacity. What is the SO₂ emission rate in metric tonnes (10³ kg) per year?

从烟道气中去除二氧化硫的平均效率为80%，工厂的平均产量为其额定容量的75%。每年以公吨（10³ kg）为单位的SO₂排放量是多少？

2.5

Methanol shows promise as an alternate fuel that could reduce nitrogen oxide emissions. The reduction is attributed to lower flame temperatures. Compare the adiabatic flame temperature for combustion of pure methanol at φ = 1 with that of methane (Problem 2.4). Initial fuel and air temperatures are 298 K. The enthalpy of formation of liquid methanol is \(\Delta h_f^\circ\) (298 K) = -239,000 J mol^-1.

甲醇作为替代燃料显示出前景，可以减少氮氧化物排放。降低归因于较低的火焰温度。将φ = 1时纯甲醇燃烧的绝热火焰温度与甲烷燃烧的绝热火焰温度进行比较（问题2.4）。初始燃料和空气温度为298 K。液体甲醇的形成焓为\(\Delta h_f^\circ\)（298 K）= -239,000 J mol^-1。

2.6

The bituminous coal of Problem 2.2 is burned in air that has been heated to 590 K. To estimate the maximum temperature in combustion, compute the adiabatic flame temperature for stoichiometric combustion assuming complete combustion. The specific heats of the coal carbon and ash may be taken as \(\bar c_{pc}\) = 1810 and \(\bar c_{pa}\) = 1100 J kg^-1 K^-1, respectively. The ash melts at 1500 K with a latent heat of melting of \(\Delta \bar\hbar_m\) = 140 J kg^-1.

问题2.2的烟煤在已加热到590 K的空气中燃烧。为了估计燃烧的最高温度，假设完全燃烧，计算化学计量燃烧的绝热火焰温度。煤炭和灰分的比热分别取\(\bar c_{pc}\) = 1810和\(\bar c_{pa}\) = 1100 J kg^-1 K^-1。灰分在1500 K熔化，熔化潜热\(\Delta \bar\hbar_m\) = 140 J kg^-1。

2.9

A fuel oil containing 87% C and 13% H has a specific gravity of 0.825 and a higher heating value of 3.82 × 10¹⁰ J m³. It is injected into a combustor at 298 K and burned at atmospheric pressure in stoichiometric air at 298 K. Determine the adiabatic flame temperature and the equilibrium mole fractions of CO, CO₂, H₂, H₂O, O₂, and N₂.

含87% C和13% H的燃料油比重为0.825，热值较高，为3.82 × 10¹⁰ J m³。将其注入298 K的燃烧室，并在298 K的化学计量空气中在大气压下燃烧。确定绝热火焰温度和CO、CO₂、H₂、H₂O、O₂和N₂的平衡摩尔分数。

Air Pollution Control Engineering

P66, 1

The range of droplet sizes in a cloud was determined to be as follows:

云中液滴大小的范围确定如下：

a. Determine the number median diameter.

确定数中值直径。

b. Determine the mass median diameter.

确定质量中值直径。

c. Determine the Sauter mean diameter.

确定Sauter平均直径。

d. What weight fraction of the sample is represented by drops greater than 20 μm in diameter?

直径大于20 μm的水滴代表样品的重量分数是多少？

e. What is the population density of the 20-23 μm grade?

20-23 μm等级的人口密度是多少？

f. Can the distribution be reasonably well described as log-normal? (Hint: try plotting Δn/Δln d_p vs ln d_p; also try the upper-limit function). If so, find the two constants for the distribution.

分布是否可以合理地描述为对数正态分布？（提示：尝试绘制Δn/Δln d_p vs ln d_p；也尝试使用上限函数）。如果是，请找出分布的两个常数。

P66, 5

The spray from a certain nozzle gave a drop-size distribution which was log-normal, with an AMD of 240 microns and a standard geometric dispersion of 2.00. For this spray:

来自某个喷嘴的喷雾给出了对数正态分布的液滴尺寸分布，AMD为240 μm，标准几何色散为2.00。对于这种喷雾：

a. What fraction of the total surface would be on drops between 100 and 200 microns in diameter?

直径在100到200 μm之间的液滴占总表面的几部分？

b. What is the value of the “surface to diameter” mean \(\bar D_{1,1}\)?

“表面对直径”的值是什么意思\(\bar D_{1,1}\)？

c. What is the value of the maximum population density?

最大人口密度的值是多少？

d. At what size does this value occur?

这个值出现的大小是多少？

P133, 1

The particle size distribution of a certain dust, as obtained by an analysis conducted partly by a Coulter Counter and partly by an Anderson Impactor, may be represented by two straight lines on a log-probability plot. These lines intersect at 5.5 μm and 19.5% finer-than, with the Coulter portion having a σ_g = 0.205, and the Anderson portion a σ_g = 11.1, with the Anderson covering the finer range. This dust is to be collected by a device which has a grade efficiency performance given by the following equation:

通过部分由Coulter Counter和部分由Anderson Impactor进行的分析获得的特定粉尘的粒度分布可以用对数概率图上的两条直线表示。这些线在5.5 μm和19.5%处相交，Coulter 部分的σ_g = 0.205，Anderson部分的σ_g = 11.1，Anderson覆盖更精细的范围。该粉尘将由具有以下等式给出的分级效率性能的设备收集：

where d_p is in microns. For this operation, find:

其中d_p以微米为单位。对于这个操作，找到：

a. the “cut diameter”;

“切割直径”；

b. the overall efficiency;

整体效率；

c. the particle size distribution of the dust emitted;

排放粉尘的粒度分布；

d. the rate of emission, per 100 kg of dust fed.

每100 kg粉尘的排放率。

P133, 4

The grade efficiency of a certain gravity (settling chamber) collector was found to be 20% on particles of a certain size and 81% on particles twice as large. Assuming the particles obey Stokes Law, what type of model might represent this collector performance? Would your answer be the same if the grade efficiencies were 25% and 50% respectively?

发现某种重力（沉降室）收集器的分级效率对于特定尺寸的颗粒为20%，对于两倍大的颗粒为81%。假设粒子服从斯托克斯定律，什么类型的模型可能代表这种收集器性能？如果成绩效率分别为25%和50%，您的答案是否相同？

P133, 5

The power consumption of a certain collector was measured as 15 kW. It was processing a stream of gas having an average molecular weight of 32, at 300 ℉ and 15.2 psia, through a duct 18’’ by 36’’ in cross-section at an inlet velocity of 50 ft/sec.

某个收集器的功耗测量为15 kW。它在300 ℉和15.2 psia下以50 ft/sec的入口速度通过横截面为18英寸 × 36英寸的管道处理平均分子量为32的气流。

Find: (a) the pressure drop across the collector;

求：(a) 集热器两端的压降；

(b) the number of inlet velocity heads of frictional energy loss.

(b) 摩擦能损失的入口速度头数。

P133, 7

It has become necessary to control the emission of cement dust from the kiln of a Portland Cement plant in which the operating conditions are as follows: temperature = 250 ℉; pressure = 1 atm; feed rate to kiln = 5 tons/hr; emission rate of dust (uncontrolled) = 230 lb/ton of feed; air flow = 159,600 acf/ton of feed. The dust may be regarded as equivalent of Stairmand Fine. The emission regulations are given in Chapter 1.

有必要控制波特兰水泥厂水泥窑的水泥粉尘排放，其操作条件如下：温度 = 250 ℉；压力 = 1 atm；窑的进料速度 = 5 tons/hr；粉尘排放率（不受控制）= 230 lb/ton饲料；空气飞行 = 159,600 acf/ton饲料。灰尘可被视为等同于Stairmand Fine。排放法规在第1章中给出。

a. Select some possible kinds of collection equipment which might be considered in order to meet this requirement. Indicate their relative costs and power consumption.

选择一些可能被考虑的收集设备来满足这个要求。说明它们的实际成本和功耗。

b. What will be the grain-loading in the feed to the collection system?

收集系统的饲料中的谷物装载量是多少？

c. Could a cyclone collector be used in any way? If so, or if not, assuming the inlet duct to be 2.28 ft by 1.09 ft, and the value of N = 9 inlet velocity heads, estimate the pressure drop across the cyclone, and the power consumption for the operation.

可以以任何方式使用旋风收集器吗？如果是，或者如果不是，假设入口管道为2.28 ft×1.09 ft，并且N = 9入口速度头的值，估计通过旋风分离器的压降和操作的功率消耗。

第2次作业

旋风除尘器

1

(a) A certain cyclone installation is collecting particles of sp.gr. = 2.5 using an inlet velocity of 50 ft/s. What inlet velocity would be required to collect particles of sp.gr. = 1.5 with the same grade-efficiency? How will the pressure drop compare with the original value?

(a) 某旋风分离器装置使用50 ft/s的入口速度收集sp.gr. = 2.5的颗粒。收集sp.gr. = 1.5且具有相同品位效率的颗粒所需的入口速度是多少？压降与原始值相比如何？

(b) The cut-diameter for a Swift high-efficiency design cyclone operating under a certain set of conditions is 2.0 μm and the pressure drop is 3.0'' H₂O. What would be the cut-diameter and the pressure drop for a Stairmand design of the same diameter D, operating at the same flow rate, temperature, grain-loading, etc.?

(b) 在特定条件下运行的快速高效设计旋风分离器的切割直径为2.0 μm，压降为3.0'' H₂O。在相同流速、温度、谷物负载等条件下，相同直径D的楼梯设计的切割直径和压降是多少？

2

A cyclone designed to operate at 20 ℃ with a flow rate of 10,800 std. cu.ft./min of air, collecting solid particles of 1.5 gm/cm³ density, has a cut-diamter of 1.96 μm. Estimate the collection grade-efficiency of particles 1.96 μm if this same cyclone were operated at 200 ℃ at a flow rate of 5000 scfm, collecting the same material. The cyclone is of high-efficiency Stairmand configuration and is 5 ft in body diameter.

旋风分离器设计为在20 ℃下运行，空气流速为10,800 std. cu.ft./min，收集密度为1.5 gm/cm³的固体颗粒，切割直径为1.96 μm。如果相同的旋风分离器在200 ℃下以5000 scfm的流速运行，收集相同的材料，则估算1.96 μm颗粒的收集级效率。旋风分离器为高效楼梯结构，体直径为5 ft。

电除尘器

1

Using the conditions and values specified for Eqn. (7.9), together with appropriate values for C_i calculate values of the size-dependent term C_iq_i^*/d_pi in Eqn. (7.3) after 1 sec for particle sizes in the neighborhood of 0.2 μm. Show that this term goes through a minimun value. Compare the particle size at which this minimum occurs with that obtained from Eqn. (7.13).

使用方程式（7.9）中规定的条件和值，以及适当的C_i值，计算方程式（7.3）中粒径在0.2 μm附近1秒后的尺寸相关项C_iq_i^*/d_pi的值。表明该项经过一个最小值。将出现该最小值时的粒径与从等式（7.13）中获得的粒径进行比较。

4

Refer to Example 1 in this chapter:

请参阅本章中的示例1：

(a) What is the value of the effective migration velocity (or precipitation rate parameter)?

有效迁移速度（或降水率参数）的值是多少？

(b) What is the “cut” diameter?

“切割”直径是多少？

(c) What value of a “mean” particle size could be used to represent the overall performance? Does this correspond to any of the “means” defined in Chapter 2? How does it compare with Cooperman's t_mean given by (7.22) and (7.23)?

“平均”粒径的什么值可以用来表示总体性能？这是否符合第2章中定义的任何“方法”？它与（7.22）和（7.23）给出的库伯曼t_mean相比如何？

(d) Estimate the value of the overall collection efficiency if the rate of gas flow were to double during operation.

如果运行期间气体流速加倍，则估计总收集效率的值。

7

The fly-ash from a pulverized coal fired furnace has a particle-size-distribution such as given in Feldman's table just below Eqn. (7.19), and a density of 2.5 gm/cm³, It is emitted at the rate of 170 lb/ton of coal fired in a flue gas stream (Mol. Wt. = 28.1) of 14.7 × 10⁶ cu.ft./hr at 300 ℉ and 1 atm. A collection system is to be designed to meet the emission regulation of 0.10 lb/million BTU. The coal used has a heating value of 12,800 BTU/lbm and is fired at the rate of 35 tons/hr. Consider the use of an electrostatic precipitator (either with or without a primary collector ahead of it) for this purpose. Estimate the collecting surface required and propose an arrangement for the plates: number in parallel, spacing, height, length and number of compartments.

煤粉炉飞灰的粒度分布如方程式（7.19）下方的费尔德曼表所示，密度为2.5 gm/cm³，以170 lb/ton煤的速率排放，在300 ℉和1 atm下以14.7 × 10⁶ cu.ft./hr的烟气流（摩尔重量 = 28.1）燃烧。收集系统的设计应满足0.10 lb/million BTU的排放规定。所用煤的热值为12800 BTU/lbm，燃烧速度为35 ton/hr。为此，考虑使用静电除尘器（有或没有初级收集器）。估计所需的收集面，并建议板的布置：平行数量、间距、高度、长度和隔室数量。

过滤器

1

(a) Repeat the calculations for the conditions of the example of fiber-bed filtration given in the text, except use velocities of 60 fpm, and of 80 fpm. Note the interplay between the face velocity values and L, A, and ΔP for each filter.

对文中给出的纤维床过滤示例的条件重复计算，但使用60 fpm和80 fpm的速度除外。注意每个过滤器的面速度值与L、A和ΔP之间的相互作用。

(b) For the conditions of this same example, assume that there is also present an image force brought about by the presence of 90 electronic charges per particle, and that the dielectric constant of the fibers is rather large. Estimate what effect this would have upon the filter dimensions for the case of 40 fpm face velocity.

对于该相同示例的条件，假设还存在由每个粒子90个电子电荷的存在而产生的镜像力，并且光纤的介电常数相当大。估计在面速度为40 fpm的情况下，这会对过滤器尺寸产生什么影响。

(c) Again with reference to the same example, how would the results of the original case for 100 fpm be affected if the required efficiency were to be 95%?

再次参考同一示例，如果要求的效率为95%，100 fpm的原始情况的结果会受到怎样的影响？

2

A dust-laden air stream of 10,000 acfm at 70 ℉ and dust concentration of 2.3 gm/m³ is passed through a fabric filter consisting of 49 bags in parallel, each bag 20 ft long and 1 ft in diameter. Cleaning is by mechanical shaking of all the bags at the same time. Tests indicate that the pressure drop is 3.28'' H₂O twenty minutes after shaking, and 3.53'' H₂O forty minutes after shaking. Determine:

在70 ℉下，10000 acfm的含尘气流和2.3 gm/m³的粉尘浓度通过由49个平行袋组成的织物过滤器，每个袋长20 ft，直径1 ft。通过同时对所有袋子进行机械振动进行清洁。试验表明，振动20分钟后的压降为3.28'' H₂O，振动40分钟后的压降为3.53'' H₂O。确定：

(a) air/cloth ratio in use during filtration;

过滤过程中使用的空气/布比率；

(b) the values of S_E and K₂;

S_E和K₂的值；

(c) time required to reach a ΔP = 4.0'' H₂O；

达到ΔP = 4.0'' H₂O所需的时间；

(d) amount of dust collected when ΔP reaches 4.0'';

ΔP达到4.0''时收集的粉尘量；

(e) the time required to reach ΔP of 4.0'', if an identical arrangement of 49 bags is added in parallel with the present arrangement.

如果与当前布置平行添加49个行李的相同布置，则达到ΔP 4.0''所需的时间。

4

Refer to Problem 7 of Chapter 7. For the conditions stated there, consider the design of a baghouse filter system to collect the fly-ash. Assume that the fabric will be fiberglass. Make a preliminary design and compare it with that for the electrostatic precipitator design done for that problem.

参见第7章的问题7。对于那里所述的条件，考虑袋式除尘器系统的设计来收集粉煤灰。假设织物是玻璃纤维。进行初步设计，并将其与针对该问题进行的静电除尘器设计进行比较。

湿式洗涤器

2

A gravity spray tower 3 m high is operating at a liquid-to-gas ratio of 1 l/m³ with a drop diameter of 400 μm. The gas velocity is 0.1 of the drop terminal velocity which is 157 cm/s. The operation is at 20 ℃. What is the grade efficiency for particles of 1 μm diameter, having a density of 2.0 gm/cm³?

3米高的重力喷雾塔以1 l/m³的液气比运行，液滴直径为400 μm。气体流速为滴头流速的0.1，即157 cm/s。操作温度为20 ℃。直径为1 μm、密度为2.0 gm/cm³的颗粒的分级效率是多少？

4

A Venturi scrubber is to be designed to collect dust from an asphalt stone drier. The dust has a mass median diameter of 1.8 μm and a density of 2.6 gm/cm³. The uncontrolled emission rate is 2310 kg/hr, but state regulations require that this be reduced to a maximum of 25 kg/hr. The air flow is 20,000 acfm at 250 ℉. No additional data are available. Assuming a throat velocity of 150 ft/s, make a preliminary determination of the necessary L/G value, and of the maximum pressure loss in the throat. Discuss the additional data and calculations which would be required to make a final design of the Venturi.

文丘里洗涤器用于收集沥青石干燥器中的灰尘。粉尘的质量中值直径为1.8 μm，密度为2.6 gm/cm³。非受控排放率为2310 kg/hr，但州法规要求将其最大值降低至25 kg/hr。250 ℉时的空气流量为20000 acfm。没有其他可用数据。假设喉部速度为150 ft/s，初步确定必要的L/G值和喉部的最大压力损失。讨论文丘里管最终设计所需的额外数据和计算。